Solar access for New York City, NY

[From the U.S. Government Printing Office, www.gpo.gov]

KEN
5468.8
.S6
P67
1988

SOLAR ACCESS STUDY FOR NEW YORK CITY

Prepared by:

Brent M. Porter, Architect, and Associates

for The City of New York, Department of City Planning,
Waterfront and Open Space Division,
Holly Haff, Director

Consultants:

Fred S. Dubin, P.E.
Henry Markus, A.P.A.
Gerard George

Staff:
Brent M. Porter, A.l.A.; Principal
Peter Kraljic
Rene Alvarez
Arthur Valente

April, 1988

C. . ... ,ATVE.T OL COMMERCE NOA/
COASl' SEFRV'!CK CENTER
22. SOUTH HOFSOIX AVENUE
CHAtL.'TON, SC 29405-2413

LL
,4
. . ,- _. :tlt o f (?;:,an

/.,L

ACKNOWLEDGEMIVENTS

The preparation of this report was financially aided through a
Federal grant from the Office of Ocean and Coastal Resource Management.
(OCRM), National Oceanic and Atmospheric Administration under the
Coastal Zone Management Act of 1972, as amended.

The New York State Department of State (DOS), as administrator of
the New York State Coastal Management Program, selected this study for
funding and has provided New York City with support and advice. In
particular, we extend our appreciation to Catherine Cousins of OCRM and
George Stafford and Neil MacCormick of DOS.

CT,-,~~~~~~~~~~~~~~~~~~

TABLE OF CONTENTS

Introduction
SECTION I
What is Solar Energy? Page 9
What is Solar Access? I10
History of Solar Access 1 0

SECTION 2
Solar Facility Site Criteria and Methodology 17
SECTION 3
Application of Siting Criteria and Methodology 27
SECTION 4
Economic Impact of Providing Solar Access 64
SECTION 5
Legal Evaluation of Providing Solar Access 79

SUMMARY OF FINDINGS -- Conclusion 87

BIBLIOGRAPHY 89
APPENDICES
Appendix I Inventory of existing solar in NYC 92
Appendix 2 Construction of a solar envelope 96

LIST OF MAPS

I Coastal Zone Management Map Page 6

2 Annadale-Huguenot, Staten Island, within
Freshwater Wetlands Map for Richmond County 32

3 STUDY AREA, Annadale-Huguenot 33

4 Plan I, Annadale-Huguenot 40

5 Plan 2, Annadale-Huguenot 41

6 STUDY AREA, East River Landing 47

7 East River Landing, property lines and dimensions 48

8 Plan I, East River Landing 54

9 Plan 2, East River Landing 58

LIST OF TABLES

I Solar compatible street trees Page 44

2 a Plan I Proposed height restrictions at each corner
of blocks (height of each solar pole) 55

2 b Plan 1, Comparison of proposed height restrictions
at each corner of each block under
as-of-right zoning 57

3 Plan 2 Proposed height restrictions at each corner
of blocks 60

4 Energy conservation comparison of conventional house
to Brookhaven House 65

5 Annual comparison of costs and savings 66

6 Diminishing return of insulation 67

7 Monitored results, Brooklyn Union Gas Solar House 70

8 Comparison of savings between conventional office
building and dlaylighted office building 74

9 Comparison of energy consumption 76

1 0 Photovoltaics 77

1 1 Azimuth and altitude of the sun 99

LIST OF FIGURES

I Solar poles which cast shadows. Page 1 2
2 Altitude and azimuth 1 9
3 Topography and solar access 20
4 Solar envelope as a "tent" over solar poles 22
5 Maximum mass diagrams, Hugh Ferriss, 1916 24
6 Solar plane 25
7 "Sun chart" with solar window partially blocked 28
8 Photographing a "solar window" 29
9 Comparative methods of projecting the sun's position 30
10 Solar window,Annadale-Huguenot site/southeast corner 37
1 1 Solar window,Annadale-Huguenot site/southwest corner 37
1 2 Solar envelopes, Annadale-Huguenot site 38
1 3 Solar window,East River Landing site/southwest corner 50
14 Solar window,East River Landing site/2:00 PM blockage 50
15 Each block as one building bulk 55
16 Each block as two building bulks 59
17 Construction of solar envelope 98
1 8 Modified solar envelopes, East River Landing site 100
1 9 Solar envelopes, Annadale-Huguenot site, including
dividing larger solar envelope into smaller envelopes 104

. . .. . iiiiiiii i

Map I. COASTAL ZONE MANAGEMENT MAP
Study Area I, Annadale-Huguenot Study Area 2, East River Landing
Ref.: From report, "Waterfront Revitalization," Dept. of City Planning

INTRODUCTION

This study, undertaken through the Coastal Energy Impact Program
jp~ (CEIP), arose as the result of the growing national interest in energy
conservation generated by the 1970's energy crisis. The study examines
the feasibility of using solar energy as an alternative energy source,
reducing the city's reliance on foreign oil, and alleviating the building of
future power generating facilities which could impact the coastal zone.
The goal of this study is to recommend mechanisms to guarantee solar
access and yet allow for the largest possible building bulk on a land parcel
without shading neighboring properties during specified times.
The study's primary objective is to investigate solar access potential
for new developments in two selected sites within the New York City
coastal zone: I) East River Landing site in Lower Manhattan, and 2)
Annadale-Huguenot on Staten Island (See Map I. Coastal Zone Management
Map.); and to examine the feasibility of implementation mechanisms to
guarantee solar access.
To understand how solar access might be used at these two sites, the
following aspects were studied:
a. The evaluation of the opportunities, constraints and cost
implications of hot water, space heating and electrical generation solar
energy systems as well as passive solar energy (such as sunlight through a
window) for residential and business uses;
b. The development of site criteria and methodology to evaluate the
solar energy potential of the waterfront sites;
c. Application of the siting criteria and methodology for two sites
along the waterfront; and

d. The review of legal alternatives for providing solar access to the
two sites under consideration.

A six-phased research project on solar access for two designated
waterfront sites was conducted. Section I reviews the solar access
literature and defines the terms and concepts used in the methodology

developed to evaluate solar access potential. Section 2 sets forth the
solar access siting criteria and methodology selected for application to
the New York City sites. The two sites are described in Section 3, and the
findings of the application of the criteria and methodology are discussed.
In Section 4 the economic impact of solar access is evaluated. Legal
mechanisms for implementing solar access are described in Section 5. A
summary of findings and conclusion follows Section 5. In Appendix I, an
inventory of New York City solar energy users and the effectiveness of
their solar systems is presented. In Appendix 2 the methodology of
constructing solar envelopes is shown in detail.

SECTION I
WHAT IS SOLAR ENERGY?

Solar energy is energy emanating from the sun that is released as it
strikes an object's surface. The amount of solar energy that is generated
depends on the tilt of the earth, the sun's location in degrees Latitude from
the North or South Pole, and the earth's topography. Solar energy radiation
can exist in two forms -- beam or diffuse. Beam radiation refers to direct
sun rays that produce shading patterns as the sun rays strike an object.
Diffuse radiation does not emanate from a point source, i.e., the sun, but is
the residue of reflected solar energy from clouds, earth and water.
Solar energy is generally collected by active or passive solar
systems. Active solar collectors intercept the solar radiation but require
other sources of energy such as electricity to distribute and store the
collected heat. A common example of an active system is a roof-mounted
solar collector covered with glass that allows water or air to flow through
the collector to a storage system, such as a hot water tank, which holds
the solar heat. Another example of an active system is photovoltaic cells
that convert solar energy into electricity.
Passive solar collectors are those parts of a building which absorb
solar heat directly or indirectly without the use of another energy source.
An example is sunlight passing through a glass window and producing heat
by striking an interior wall. Passive solar energy is commonly found in a
south-facing room with ample window area and enough bricks or concrete
in the walls and floor to absorb and retain the heat from sunlight. One
common passive solar technique involves the construction of a greenhouse
or a sunspace on a building's southern exposure. The greenhouse functions

F~~~~~~~~~~~~~

in the same fashion as the collector in an active solar energy system; the
heat is collected, absorbed and stored for use in the greenhouse to make it
energy self-sufficient. A sunspace is physically similar to a greenhouse,
but it provides heat to adjacent areas in the building. The greenhouse and
sunspace are glass-enclosed rooms or balconies with sufficient "thermal
mass" (i.e., the bricks or concrete) to absorb and retain heat. If there is
insuffient thermal mass, overheating occurs.

WHAT IS SOLAR ACCESS?
Solar access is the legal mechanism that ensures sunlight will reach
a building for a designated period of time without obstructing sunlight to
adjacent properties.

HISTORY OF SOLAR ACCESS
Using solar energy to provide heat is not a new concept. Years ago,
houses in New England were strategically situated to take advantage of the
sun's energy for heating purposes. In the middle of this century, however,
as abundant and cheap energy sources became increasingly available,
buildings and communities were developed without regard to solar energy.
Today, with the increased cost of conventional fossil fuels, interest
in the use of the sun's heat is reemerging. However, the value of solar
M ~facilities that harness solar energy diminishes as access to direct'
sunlight is decreased.
One of the first guarantees of solar access was contained in the
English common law doctrine of "ancient lights" which held that windows
of private residences that had access to sunlight for a given period of
time created a presumptive easement of light in perpetuity. The first

1 0

serious investigation of solar access as a tool in planning began with
research on the design of school buildings in the 1880s. Maurice Javal, a
French opthalmnologist, proposed that school buildings be set within a
protective zone which limited adjacent structures to a distance twice
their height from the school buildings to assure access to sunlight. Other
studies followed, many proposing mechanical methods for assessing and
requiring adequate provision of daylight to schoolrooms.
In 1923, utilizing the results of a number of these studies, J.M. and
Percy Waldrarn elaborated a method for measuring and predetermining
daylight illumination within buildings. The analytical method they devised
was the precursor of the Waldram diagram, which is simply a means of
measuring the effect of building configuration on the amount of light and
air penetrated to the street. The Waldrarn diagram is drawn in a vertical
format (See Figure 6.). The Waldramn diagram has been made a part of the
bulk regulations for zoning in Midtown Manhattan and has long been in use
in town planning in Great Britian.
In the last two decades, numerous researchers have examined the
issue of solar access. William A. Thomas of the American Bar Foundation,
Chicago, Illinois, extensively reviewed laws pertaining to solar access and
drafted model legislation in 1978.1 Thomas' model legislation provided
legal alternatives for cities and counties to enact solar access through
covenants, easements and zoning. Gail Boyer Hayes wrote the SOLAR
ACCESS LAW book which is the most thorough reference on solar access;
she updated Thomas' research by expanding upon his concepts.2 Ms. Hayes'
research was followed by two workbooks by Martin Jaffe which illustrated
how solar access concepts could be used as planning tools.3 Jaffe's work
focused upon low-density solar access. Jaffe repeated solar law

definitions provided by Thomas, as Hayes did, but was the first to develop
the term "solar pole" and provide clear diagrams of this term, as shown in
Figure I. Jaffe used each pole to represent any object above ground that
will cast a shadow without shading a neighboring property.

I
/
! ~ m~ J

Fig. I. SOLAR POLES WHICH CAST SHADOWS.

In a 1980 report, Ralph Knowles and Richard Berry presented to the
City of Los Angeles a new alternative to solar access.4 They addressed
several issues concerning the trade-off between development potential and
solar access protection for moderate-density commercial and residential
development. This report concluded that closely spaced structures will
not shade each other if properly planned.
Ralph Knowles was one of the first to apply planning criteria to solar
access. He developed the concept of the solar envelope for use as a tool
for site analysis at the Univeristy of Southern California between 1969 and
1971, and published in ENERGY AND FORM in 1974.5 A solar envelope is
defined as the maximum volume which can be built upon a property within
which a building will not shade adjacent lots or buildings. Knowles'
impact has been in low-to medium-density urban areas such as Los
Angeles, which implemented the solar envelope as a zoning and design
mechanism in a medium-density area, the Park Mile Plan Study area.6
A study conducted in 1981 by Stuart White et aL found an abundance of
solar access opportunities in New York City.7 The city has many
south-facing walls along streets that run in an east-west direction, which
create buildings with a predominant southern exposure. South-facing
walls present many solar access opportunities because they naturally
receive more sunlight than other walls. The study also concluded that
conventional high-rises have less heat loss than single-family residences
on a per-square-foot basis. Conventional high-rises have less surface area
exposed on a per-square-foot basis than free-standing structures and
therefore experience less heat loss. Daylighting, the use of sunlight for
the illumination of interior spaces, another form of passive solar energy,
can reduce the consumption of electricity used for artificial lighting. The

White study suggests that passive solar energy has far more potential than
other local solar experts had thought. (For an inventory of active solar
energy collectors in use in New York City, see Appendix I.)
In 1984, Oregon enacted enabling legislation for counties to zone for
solar access. These counties in turn were permitted to recommend to the
cities under their jurisdiction to enact solar access legislation. Over
twenty municipalities enacted solar access zoning provisions. Portland

passed an ordinance assuring single-family homes access to sunlight on
their south walls. In March of 1985, the Oregon Department of Energy
published an easy-to-read handbook, entitled THE SOLAR ACCESS TOOL
KIT.8 The handbook included model subdivision zoning and model solar'
covenants and easements.
Massachusetts created a Multi-Family Passive Solar Program in 1979
which continued through 1983.9 The program became the national model
for construction of passive solar heating and cooling of multi-family
buildings because it was the first to go beyond single-family houses.
Recently, a number of simulation techniques, many in use since the
early 1970s, have attracted attention for their ability to demonstrate the
effect of building configuration on light and air through the photographic
manipulation of solid models. One such method is that developed by Peter
Bosselmann, the director of the Environmental Simulation Laboratory at
the University of California at Berkeley. The Berkeley simulator uses a
modelscope which contains a collection of miniature lenses and prisms
that allow the scope to be driven through small-scale physical models
with video or still cameras attached to produce the perception of traveling
'through an environment at ground level. The simulator also uses a "solar
fan," a plexiglas sleeve that shows where and how buildings cast shadows

at different times and in different seasons.1 0
The research by Bosselmann is being used to assist in the
implementation of a new ordinance for downtown San Francisco.1 1
Bosselmann's work integrates solar access and daylighting for the
downtown buildings with other urban design criteria.
In 1983, Brent M. Porter et al. studied sunlight and open space
opportunities at Greenacre Park, East 51st Street, New York City, in
response to a proposal to build a high-rise at 805 Third Avenue. "Before"
and "after" sunlight and shading were demonstrated by comparing a scale
model depicting the existing conditions at the site with a scale model
depicting the proposed new development. The results of the simulation
were presented by William Whyte at a New York City Board of Estimate
(BOE) hearing. The simulation demonstrated that the top four stories of
the proposed new high-rise would create excessive shading. Based on this
conclusion as well as other factors, the BOE denied the top four stories of
the high-rise. On-site photographs taken after the 805 Third Avenue
development was completed show the resultant impact and the accuracy of
the simulation using a scale model. Without the additional four stories,
the sunlight is preserved throughout much of the autumn, winter and
spring at lunchtime when the park is frequented by the public. Although
the high-rise at 805 Third Avenue blocks sunlight after approximately 2:00
PM, its total impact on solar access is less than what would have occurred
had the top four floors been added.
More recently, in May of 1987, a precedent was set when the property
owner south of Greenacre Park donated his right to build more bulk on his
property by granting an easement to the New York Landmarks Conservancy
to protect the park.12 The donation marks the first use of this type of

easement intended to protect and maintain the quality of an urban open
space which is very dependent upon sunlight.
These examples of solar access criteria, methodology and
implementation found in the literature provide the background to develop
an approach appropriate for New York City.

SECTION 2
SOLAR FACILITY SITE CRITERIA AND METHODOLOGY

This section provides the siting criteria and methodology for the
application of solar access to selected low- and high-density sites in New
York City. The siting criteria is a set of guidelines that are incorporated
into a methodology which helps determine the solar access potential of a
particular site.
SITING CRITERIA
The siting criteria selected to preserve solar access are: southern
exposure, solar window, latitude, topography, structure and bulk, lot and
building orientation, street configuration, and shading. All of these terms
will be discussed in their relationship to solar access.
Southern exoosure -- New structures should have southern exposure
to maximize solar energy during the winter months. A southern exposure
is necessary to maximize the amount of sunlight received between 10:00
AM to 2:00 PM throughout the year when sun rays provide the most heat
measured in BTUs per square foot. (BTU is "British Thermal Unit" which is
the standard unit of measure of heat.)
Solar window -- Any solar energy system must "see" the sun. The
space between the solar facility and the sun moving in its arc across the
sky is called a solar window (See Figure 7 and Figure 8.). It is the solar
window, the solar facility's unobstructed view of the sun, that must be
protected for the solar energy system to be effective. To compute the
necessary solar window for a particular area involves the determination of
the sun's altitude at solar noon at the winter and summer solstices when
the sun is at its highest position in the sky on the shortest day of the year,

1 7

December 21, and at its highest position in the sky on the longest day of
the year, June 21. This determines the highest elevation of the top and
bottom curves of the solar window. The sun's position at other hours of
the day complete the top and bottom curves.
On December 21, the winter solstice, the sun is in its lowest position
in the sky throughout the day, and structures or trees cast their longest
shadows of the year. If on this day solar facilities can be protected from
shadows for a six-hour period beginning three hours before solar noon and
ending three hours after solar noon, then shadows will not pose problems
for solar facilities during the remainder of the year when the sun's
altitude is higher.
Solar noon determines the lower limit of solar window for a given
location. Solar noon is the time when the sun reaches its highest position
and its radiation will be most direct. However, solar noon does not exactly
coincide with local time. For example, in New York, the sun rises over the
eastern tip of Long Island almost one-half hour before it rises over
Buffalo. To find solar noon, simply determine the time halfway between
sunrise and sunset. This information can be found in local newspapers.
Low solar altitudes may affect structures in an adjoining area due to
long shadows. Therefore, an alternate date in November or January when
the sun's altitude is incrementally higher could be used to determine this
lower limit and will only slightly limit yearly solar access. The upper
limit of the solar window is determined by the sun's altitude at solar noon
on June 21, the summer solstice, and is especially critical when
determining whether high, nearby buildings block sunlight.
Once the solar window's upper and lower limits are determined, it is
then necessary to determine the eastern and western boundaries of the

solar facility which must also be protected. In New York City, solar
facilities should be protected from approximately 45 degrees east of true
South to approximately 45 degrees west of true South. The availability of
sunlight to a solar collector from 9:00 AM to 3:00 PM will establish
southeast and southwest solar window boundaries that accommodate
approximately 85 per cent of the sun's available energy striking the earth
on a particular site.
Latitude -- Latitude, expressed in degrees, establishes the distance
north or south of the equator where a particular land area is located and
determines the sun's altitude and azimuth angles where solar radiation
will be available. Altitude is the sun's position at a point perpendicular
above the horizon and measured vertically in degrees. Azimuth is the sun's
position from that point dropped down to the horizon and measured
horizontally in degrees from true North (See Figure 2.). New York City is
located at 40 degrees North Latitude, which is within the feasibility range
of receiving substantial direct sunlight, and the shadows cast by building
or trees will be less as compared to higher latitudes. At higher latitudes,
for example at a location further north, the sun's lower position in the sky
will cause buildings or trees to cast longer shadows.

>0 SUN

Fig. 2. ALTITUDE AND AZIMUTH.

Toooaraohv -- The term "topography" refers to all the physical

features of an area including the relief and contour of the land. Topography
is important because it affects the amount of solar energy reaching a

particular site and affects the shadow lengths that are projected by
adjoining structures and trees. Unlike latitude, which is constant,
topography is the lay of the land and can cause local variations in available
access to sunlight and impingements on sunlight because of the effect of
shadow length.
In general, access to sunlight is easier to protect on south-sloping
areas, where the land is more perpendicular to the sun rays, than it is to
protect on flat areas or on difficult north-facing slopes. Buildings, trees
and other objects will cast shorter shadows on south-facing slopes, as
seen in Figure 3.

VUN
North South

Shadow Shadow Shadow
Length Length Length
1~~~~~~ 3

Fig. 3. TOPOGRAPHY AND SOLAR ACCESS
Note: The same size tree will cast a longer shadow on flat areas (3) than
on a south-facing slope (2), and will cast a much greater shadow on a
north-facing slope (I).

Structure and bulk -- Bulk is the term used to describe the size and
shape of buildings or other structures, and their relationships to each-
other and to open areas and lot lines. Configurations of structure and bulk
should be evaluated for their shading effect. Factors that are considered
in structure and bulk evaluation for solar access are roof heights,
mandatory setbacks, and allowable projections. For example, different
roof heights might cause excessive shading to lower buildings, or

apartment balconies which are allowed might shade windows which need
to receive passive solar energy.
Lot and buildina orientation -- Individual lots should be designed to
accommodate appropriate lot-building relationships. The lots should
provide the availability for buildings to be oriented toward the south
without shading their neighbors to the east and west. Zoning regulations
for rearyards, sideyards or setbacks may limit the flexibility to orient
buildings for the best use of solar energy. On larger sites or in special
districts appropriate orientation will be easier to accommodate.
Street confiauration -- To allow buildings to have long walls facing
south, the streets should be oriented in an east-west direction while
limiting the number and length of north-south streets.
Shading -- Shading by neighboring buildings must first be considered
to see if any impingement on solar access exists. Secondly, trees and
shrubs should be sited to maintain solar access. Partial shading of active
solar facilities can result in substantial reductions in efficiency. On the
other hand, passive solar facilities such as space heating and cooling rely.
on the effective management of shade; no shade in winter but necessary
shade in summer. Deciduous trees, which drop their leaves during the
autumn and grow new leaves in the spring, are ideal for this purpose.

Trees located on the southern and western sides of a structure allow
substantial amounts of sunlight for solar space winter heating and provide
shade for summer cooling.

METHODOLOGY
A comprehensive methodology that incorporates the siting criteria to
* ~~facilitate solar access for a particular area is the solar envelope.
A solar envelope is the shape which defines the maximum volume
which can be built upon a property within which a future building will not
shade adjacent properties and buildings. A solar envelope is analogous to a
circus tent above a property that restricts the height and shape of the
structure underneath it, as seen in Figure 4.
A "modified solar envelope" is a solar envelope which is constrained
to allow limited shading to adjacent properties and buildings, a condition
brought about by difficult, high-density development conditions.

Fig. 4. SOLAR ENVELOPE AS A 'TENT` OVER SOLAR POLES.

2 2

The information necessary to construct a solar envelope consists of

the positions of the sun over the site for the yearly period; a map of the
site including existing roads, existing buildings, adjacent properties, and
trees surrounding the site, and the drawing technique.
The tent-like concept of sloping planes to simulate solar access dates
back to the bulk plane provisions of the 1916 New York City Zoning
Resolution. Provisions attempted to insure adequate light and air for
public outdoor spaces and for occupants of buildings. To do this, the bulk
of buildings was decreased as the height of the building increased.
Setbacks governed the decrease of bulk as a building stepped back from its
lot line. The setback angle began several stories above the lot line, but
then the angle sloped inward from each lot line along a street. The result
was a "wedding cake," stair-stepped building configuration. Thus, the

blockage of sunlight was lessened because sunlight could penetrate at the
sides of a building and reach other buildings or urban spaces behind.
Several new skyscrapers of the period, when examined together as an urban
design, in effect create valleys between them. The availability of
sunlight, though impeded by the central core of the building, is spread more
uniformly because of the "valleys." The drawings by Hugh Ferriss in
1916-1917 gave a bold vision of the potential high-rise volumes which
would conform to the angular setbacks (See Figure 5.). Today, the early
zoning provisions are reflected in "sky exposure planes." These planes
incline at various angles. However, the solar envelope's sloping planes
represent a mathematical sum of the sun's rays reaching a site at various

times throughout the year. At a given position of the sun, a plane can
represent an infinite number of sun rays, side by side, and all striking a

site parallel to each other. This is a "solar plans" (See Figure 6.).

- ~24

Jo~~~~~~~~~~~~~~~~~~~~~~~~~~.~~

Fig. 6. SOLAR PLANE.

The solar envelope, to work properly, must be applied to all land
parcels within a selected district. This approach allows lot owners access
to direct sunlight for active and passive solar use.
In developed areas, the infrastructure and shading by existing

buildings as well as the compliance with solar planes must be considered
to determine developable volume. The solar envelope consisting of the
solar planes may cast its shade on streets and open spaces. The "modified
solar envelope" may extend its shade on the lower portion of an adjacent
building in high-density development areas. Once a solar envelope is
generated for a particular site, it maintains a static relationship to the
remainder of the local environment.

The envelope configurations are based on known solar angles; thus, it
is possible to develop computer programs that can generate solar planes,
mathematically add them together, and produce solar envelope volume
when lot size and orientation are known. Envelopes for many lots within
selected districts could be inexpensive to produce and duplicate
graphically.
Solar envelopes should only be applied to sites that currently have
access to solar energy and that can benefit from the preservation of
sunlight to the site for the future through adequate regulations.
The graphic construction of solar envelopes is discussed in Appendix
2.

SECTION 3
APPLICATION OF SITING CRITERIA AND METHODOLOGY

The siting criteria and methodology developed in Section 2 were
applied in two selected sites in the Coastal Zone, Annadale-Huguenot and
East River Landing. These two sites were selected as potential areas for
solar access because of their southerly orientation, unobstructed solar
access, lack of development on-site, and their location within the
boundaries of the coastal zone. The Annadale-Huguenot site in Staten
Island is a low-density residential area in the middle of a 1,080-acre
former urban renewal area. The second site, East River Landing in Lower
Manhattan, will contain a mix of high-density residential and commercial
development built on a decked structure along the FDR Drive.

SITE EVALUATION

Preliminary site evaluation using a "sun chart" (Figures 7 & 8) can
determine whether a solar envelope should be drawn.
The sun chart shows an eye level view of trees and buildings that will
block part of the available sunlight. For example, as seen in Figure 8, a
structure blocking direct sun rays to the property at a particular part of
the day will appear as a protrusion within the frame of the ''solar window."
Photographs taken at each corner of the property and corners of adjacent
properties will record the preliminary site evaluation of the availability-
of direct light. No obstacles appeared through the "solar window" on the
sun chart for the Annadale-Huguenot and East River Landing sites.

8:00 9:00 10:00 11:00 1:00 2:00 3:00 4:00

Solar \ \ . Solar

window window

morn. in.. t-- X'~ afternoon

limit ; limit

Fig. 7. SUN CHART WITH SOLAR WINDOW PARTIALLY BLOCKED.

A solar window is documented by means of phoptography. As Figure 8

shows, a photographic apparatus is needed which will allow the camera to

record the sun chart at a correct scale within the photograph taken at the

site.

This process is similar to other methods for establishing the position

of the sun in relationship to a given site. Following the British example in

which the Waldram diagram was used, similar methods were developed in

the United States in the 1940s through the 1970s (See Figure 9.). Whereas

the Waldram diagram shows how sunlight strikes a vantage point by

presenting the sun's movement in a vertical plane, Americans tended to

show the same information projected on a hemisphere. The sun's

movement from a given vantage point is drawn on the hemisphere as if a
windshield wiper had swept the surface. Libbey-Owens Ford Glass Co.
produced a widely used tool, the Sun Angle Calculator, which in effect
flattened the hemispherical projection to a flat, horizontal plane. More
recently, the sun chart method has brought the return to a vertical format,
except the sun's movement in relation to a vantage point including that of a
camera is curved from east to west similar to the "windshield wiper"
diagram of the hemispherical projection.
In all methods, the positions of the sun in the sky are accurate, but
these positions are plotted differently. Emphasis is placed upon access to
sunlight at the given vantage point spanning from morning until afternoon,
particularly for those hours when most of the sun's energy is emitted.

~~~~~~~~ 9

South

WALDRAM

HEMISPHERE

S
L.O.F. CALCULATOR

SUNCHART

Fig. 9. COMPARATIVE METHODS OF PROJECTING THE SUN'S POSITION.

ANNADALE-HUGUENOT SITE.

Annadale-Huauenot site
The Annadale-Huguenot area is located in the South Richmond special
district of Staten Island and is zoned RI-2 and R3-2 (See Map 2.). The area
is bounded by Desius Street to the north, Arbutus Avenue on the east,
Louise Street on the south, and Kingdom Avenue on the west. In the site's

center are designated wetland areas and open space for passive recreation
(See Map 3.).
The site has a long history of sporadic development starting in the
late 1700's when farmers were attracted to the area for its fertile soil.
The construction of what is now called the Staten Island Rapid Transit
Line (SIRT) spurred development in the mid-1800's along the railway's
right-of-way. Large farms were subdivided into smaller farms, and small
villages sprouted over the area. Annadale-Huguenot, never a rich area,
maintained a steady economy that was ripe for speculative ventures in the
early 1900's.
Land speculators, anticipating an economic bonanza, acquired
properties along the expanded and improved SIRT right-of-way. The
general economic depression of the 1930's caused many of South
Richmond's landowners to default on their property taxes, making New York
City the area's largest landholder.
In the 1960's the city realized that some comprehensive economic
revitalization plan was needed and established the Annadale-Huguenot
urban renewal area in 1969. The plan generally focused on creating
affordable low-density residential housing, public access to large open
spaces, preservation of freshwater wetlands, and maximizing the natural
features of the area for the local and city residents. The designation as
an urban renewal area was eliminated.

AnnadIle -

V A

\~eno 1 5

-~~~~~~~~~~~~~~~~~~a

~~q,~Pri

A B 1~~~~~~~~~

RARITAN BAY

___ N .1~~~~~~~ \g
,~~~~~~~~~'xx~~~~Bah-n ruu

6 ~~(em Cree 0 ~-z-

St Edw" ia

Princes Bay

NORTH

w E STATEN ISLAND

s ~~ Map 2. ANNADALE-HUGUENOT, STATEN ISLAND, within
Freshwater Wetlands Map for Richmond County, No. 4 of 4,
Effective July 23, 1987, Dept. of Environmental Conservation.

3 2

INN4~~~~~~~~~~~~~~~~~
w~~~~~~~~~~~~~~~~~

Map. 3. STUD AREA, ANNADLE-HUGUENO0

3 3~~~~~~~~~

SITE CONSTRAINTS AND GUIDELINES
Zoning
South Richmond Special District zoning and underlying zoning are

listed below:

For RI-2 Detached type of residence

Minimum lot area: 5700 sq. ft.
Minimum lot width: 40 ft. for 1-2 stories
50 ft. for 3 stories
60 ft. for 4 stories
Minimum front yard: 18 ft. in depth
Minimum side yards: 15 ft. total width, 1-2 stories
20 ft. total width,3-4 stories
Minimum width, side yd.: 5 ft.
Minimum rear yard: 30 ft.
Front wall height: 25 ft. sky exposure plane at
I to I ratio (or 45 degrees)
above 25 ft.

For R3-2 Three residence types: Semi- Detached Attached
detached
Minimum lot area:
(1-2 stories) 2375 3800 1 700
(3-4 stories) 3800 4275 2280
Minimum lot width:
(1-2 stories) 24 40 18
(3-4 stories) 40 45 24
Minimum front vards: 18 18 18

Semi- Detached Attached
detached
Minimum side vards:
(1-2 stories) 9 15 10
(3-4 stories) 15 20 10

Min. width/side yard:
(1-2 stories) 9 5 10
(3-4 stories) 15 5 10

Minimum rear vard: 20 20 20
(with 10 ft. rear setback above the first story)

Other restrictions: No building shall exceed a
height of four (4) stories, and
no structure other than the
building shall exceed 50 ft.

Front wall height: 25 ft.

In addition to zoning, the following Department of City Planning
site guidelines were used:
I. Open space and wetlands must be maintained to the maximum
extent practicable.
2. Development must be compatible with the neighborhood

character.
3. Street layout is flexible.
4. Underlying zoning is retained.

Topography
The undevelopable parts of the Designated Open Space slopes to
the south, while the developable land is flat. Thus, objects cast shorter
shadows than if the land was sloping to the north.

Southern Exoosure
The dimensions of the developable sections of the study site were
arranged on an east-west axis, thus permitting maximum building
orientation to the south. The western section of the site has a north-south
elongation. It was necessary to arrange the section with east-west access
roads to create an east-west orientation for maximum southern exposure.
This permits the maximum use of available sunlight for this site.
Solar Window
Sunchart photos showed possible shading from existing trees in
the Designated Open Space for both sections of the site. Trees also partially
shade existing streets bordering the site. Figures 10 and 11 show these
conditions.
Shadina
The western developable portion of the site is shaded by trees
within the Designated Open Space. The western section receives most of its
sun from across the Designated Open Space. The western section receives
most of its sun from across the Designated Open Space. Measures were used
to minimize shading (See Street Confiauration). The eastern developable
section of the site is not shaded by Designated Open Space trees because of
the section's relationship to the Designated Open Space. Sunlight will strike
the eastern section from the west and south and will not have to cross the
tall trees in the Designated Open Space to reach this section.
Street Confiouration
East-west streets were laid out to maximize southern exposure
and minimize shading. Street trees were selected to specifically minimize
shading and to be suitable to the soil and water conditions of the site.

8:00 9:00 10:00 11:00 1:00 2:00 3:00 4:00

....... ~.*' 4 I

J~~Mot

Fig. 10. SOLAR WINDOW, ANNADALE-HUGUENOT SITE.
Sunchart photo at southeast corner of study site.

Fig. 11. SOLAR WINDOW, ANNADALE-HUGUENOT SITE.
Sunchart photo at southwest corner of study site.

Structure and Bulk
Buildings should be as low in height as possible to minimize the.
length and width of shadows. The overall bulk is determined by the solar
envelope as constructed to provide the maximum bulk without shading
neighboring property (See Appendix 2.).
Parcel Size
The size of parcels was determined by the solar envelope as
constructed so that yards and open space catch the shadows from buildings
and trees.
Buildina Orientation
Buildings should be orientated in an east-west direction so that most
walls and windows face south. Buildings should be located in the center of
the lot farthest from their adjoining neighbors to decrease the possibility
of buildings casting shadows on each other. This is seen in the solar
envelope. Its four sides slope outward, diminishing gradually as each side
reaches the ground (See Figure 12 and Appendix 2).

Larger solar envelope... .diided into smaller envelopes.

Figure 12. SOLAR ENVELOPES, ANNADALE-HUGUENOT SITE.

3 8

APPLICATION
Two site plans were constructed to show possible ways of
incorporating all the site criteria and to demonstrate how the solar.
envelope methodology is applied.
Plan 1
The first plan (Map 4) shows traditional land-use patterns of
single-family housing on the west and townhouses on the east. The
single-family structures are individually owned, while the 1R3-2 zoned
townhouses are either jointly (co-ops) or privately owned. The lots are
configured according to site criteria and other solar envelopes. The
streets run in an east-west direction to maximize the advantages of
south-facing walls to catch the sun, and are situated to receive the shade
of the buildings.
Plan 2
The second plan (Map 5) shows large-scale development by one owner.
Building bulk in each zone is shifted or clustered together to create a
varied texture that has many benefits. The sharing of exterior walls will
reduce heat loss, so less heat will be required to warm the homes. Open
spaces and play areas are possible with attached structures. Clustering
also results in fewer roads, which increases open spaces and reduces
development costs that would in turn reduce housing prices.

Is~~~5

'j~~~~5

- - .9 ~~~~~~~~~~~.

* ,~~~~~~~- w~~~~~~~~~i" ~~~~~1

1-~~~~~~~~~~~~~~~~~~~~~~~~~~~~0

gO~~~~~~ 0

4. I -~~~~~~~~~~~~~~~~~~0

NORT

E~~~~~~~~~~~~~~~~~~~~~~~~~

-000,~~~~~~~-

4 \

Common elements in both olans
There are common general elements in both plans. Residences can
shade the street or open spaces at any time as long as the shading is not
cast on neighboring buildings from 10:00 AM to 2:00 PM.
The specific recommendations for street direction, lot size, building
configuration relative to lot size, parking provisions, and control of
placement and species of trees for Annadale-Huguenot are as follows:
I. Lots along east-west streets will meet the requirements of the
South Richmond Special District. Southern exposure for housing along
east-west streets is maximized while maintaining lots 95 to 100 feet in
depth. No housing fronts on north-south streets. A short north-south
street, Stetcher Street, serves to connect three east-west streets with
cul-de-sacs.
2. The cul-de-sacs of east-west streets allow for easy access to
the Designated Open Space without crossing private lots.
3. Parking is provided along east-west streets in the R3-2 zoned
area. Parking for the R1-2 zoned area (single-family homes) occurs within
lots.
4. Current zoning provisions for lot size and yard requirements on a
zoning lot located in R3-2 districts may require some South Richmond
Development District Sub-Area modifications in order to guarantee solar
access and to avoid any shading of one building by another in these
districts. The provision that homes are to be constrained by solar
envelopes is central to any modifications.

R1-2 Zoned Area
The only change to the R1-2 zoned area is the provision for a 20 ft.
front and rear wall height with a setback at a ratio of 1 to 1 (45 degrees)
above 20 ft. This provision will assure that a single-family dwelling
centrally located on the minimum lot size (5700 sq. ft., with 40 ft.
minimum width) will not shade its immediate neighbor's south walls and
roof.
R3-2 Zoned Area
South Richmond Special District

No changes to the minimum lot area and the minimum lot
width. Changes to yard requirements as follow:

Current Drovisions Prooosed chanaes

Minimum front yard of 18 ft. Minimum front yard of 15 ft.
(to allow an increase in the
rear yard requirement)

Minimum rear yard of 20 ft. Minimum rear yard of 30 ft.
for 3-4 stories which have
a 20 ft. front and rear wall
height with a setback at a
1 to 1 ratio (or 45 degrees)
above 20 ft.

Below is a list of options available should implementation become
appropriate in the Annadale-Huguenot area of the South Richmond Special
District of Staten Island. These options are as follows:
1. Establish a condition of sale from the New York City Department
of General Services, Division of Real Property, requiring the new property
owner to obtain authorization from the New York City Planning Commission'
coupled with a text change to Z.R. Sections 107-62 or 107-41.

2. Add a text change to incorporate a Sub-Area designation in the
South Richmond Special District for the Annadale-Huguenot Study Area
including specific yard, building height, and tree type requirements.
Shadina bv Street Trees

To further insure solar access, only deciduous street trees should be
planted in the Annadale-Huguenot Study Area. (The study site lies within
the Special South Richmond Development District in which existing trees
greater than six inches in diameter cannot be removed. Most existing

trees in the study area are deciduous; therefore, their impacts upon solar
access will be minimal.) More deciduous trees should be located on the
southern side of east-west streets so that shadows will be cast into the
streets. Five species are recommended: Callery Pear, Higan Cherry,
American Hornbeam, Amur Maple, and Hedge Maple (See Table 1.).

Table 1. SOLAR COMPATIBLE STREET TREES.

special growth special growth
conditions characteristics
unique soil and water light SMALL ornamental special
conditions TREES qualities uses

_= _.3 TO 301 X

10
_ - X E - . ' - > . _ _ D

Reference: Adapted from "Trees," published by the New York City
Department of Planning.

The five species are solar compatible street trees for New York City's
coastal climate. Characteristics of each are summarized below:

"Pear, Callery" (Pyrus caleryana). The Callery produces an abundance
of foliage in May and in the fall, then sheds its leaves in winter and spring,
thus allowing sunlight to reach solar buildings. This tree is recommended
for streets and windy locations. The tree requires full sun and soil that
retains moisture well, although it can withstand drought.

"Cherry, Higan" (Prunus subhirtella). A deciduous tree which does not
block sunlight in winter and spring, it is tolerant of most soil conditions.
As with any tree planted on the street, it should be watered regularly.
Like all cherries, it needs a location out of the wind, and at least a few
hours of direct sunlight each day. However, it thrives in full sunlight
where it produces its best blossums.

"Hornbeam, American (Carpinus caroliniana). Also called "Ironwood"
or "Blue Beech," this deciduous tree is multi-trunked. The tree is difficult
to transplant, grows slowly, and with its multi-trunks may slightly block
winter sunlight as compared to other trees recommended. When pruned to
a single trunk, it makes a good shade tree in summer.

"Maple, Amur" (Acer ginnala). An extremely hardy, deciduous, rapidly
growing and relatively pest free tree, it is often used when a small shade
tree is desired. It tolerates strong winds, grows in most soils and prefers
a sunny or partially sunny location.

"Maple, Hedge" (Acer campestre). When it is desired to place a tree on
the street and it is to be located immediately north of a building, this tree
is a good alternative. It will thrive in full sun but will grow where only
partial sun is available. Its dense foliage in summer provides a hedge or
screen. It transplants easily and grows in all but the most extreme soil
conditions.

A sixth tree and alternate selection for any of the above street trees
is the "Russian Olive" (Elaeagnus angustifolia). It is multi-trunked, with
slender trunks, limbs and branches. It is usually pest free and tolerant of
drought, strong winds and salt-air conditions. The Russian Olive grows
quickly in a sunny location. Ref.: Adapted from "Trees," op. cit.

East River Landina site
The East River Landing is in the Special Manhattan Landing Development
District. The area is bounded on the north by Maiden Lane and runs 1600 ft.
along the waterfront to the Port Authority heliport. The landing will extend
600 ft. into the East River from the current bulkhead (See Maps 6 and 7.)
East River Landing has many unique features. It will replace now
defunct piers and wharves that were productive in the age of clipper ships.
The area was once one of the major resources that made New York a great
port city. East River Landing is adjacent to the financial district with all of
its high-rises and dark, congested streets. Five streets will cross
underneath the FDR Drive, creating five blocks on the East River Landing,
which will have a southeast to northwest axis. View corridors will be
maintained on existing streets. The construction of East River Landing will
once again unify the downtown area with the waterfront while providing
open space, sunlight to the new buildings and streets, and allowing for
scenic vistas of the harbor.

CONSTRAINTS AND GUIDELINES
The Special Manhattan Landing Development District was established to
strengthen the business core, incorporate housing in Lower Manhattan, take
advantage of the amenities of the East River waterfront and improve
pedestrian circulation. Specific standards apply to each parcel in the
district which generally can be described as a high-density mixed use area.
The Department of City Planning is re-evaluating the special district and
may suggest amendments in the future.

tA 4 ('4 si

C,-.�s;, x

v ~//
- 8~~ s I ppPRK

,~~
r4'~.. A,~!5 * 4'4e -,

~~~ .�, iC 7~~,

"CR~ ~~~~~'

, 'L, :~ _ -= ~ ~~~--"

"',' ~NORTH
CD~~~~~~~~~~~~~~~~~~~~~T\

-A~
,,~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~'

z ''~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.'
C~'K -r

W YOR B

4,Mp6 TDYRA EATIVELNIG

"�47
or 42' C' '

sr P

�i ', .,.
c-%

0: 4,

0 .4,IF._rX cF' -

4~ ~ 4
NORTH - 'I

-A~~~~~~~~~~~~~~~~~~~~~~~~~~~~~,
-A

-z

. NEW YORK BAY

j00 o0 '.,~L'Fa1S
: II!--- to--
1000 0 1000 2000 FFET �

Map 6. STUDY AREA, EAST RIVER LANDING.

I~~~~

/ I

,1~~~re,
\ji~ ~ - v/ /�I,~o

/~~~~~~~~dr
4/~~~~~~~~~~~roc

~~~~~;UJ~~~~~~~~~ /I) I

\JK .4' -~~~ / kie 0%dl' y
/~~~"aJ
3�~~~~~: bo~~~~~rL~~~(

I /~~~~~~~~~~~~~~~~~~~~~

(~~~.
/ '4)~~~S
'S A/v1

0�~
l,0 N

M'ap 7. EAST RIVER LANDING, PROPERTY' LINES & IESO.

/ P IEN OS

The Department of City Planning guidelines for urban design in this
area include:

I. Provisions for waterfront esplanade and other public open spaces.
2. Retention of view corridors.
3. Extension of street walls.
4. Integration of the new development with an expansion of the
existing street grid of Lower Manhattan.
5. Provision of areas for ferry terminals.

EVALUATION OF SITING CRITERIA
Topography
East River Landing will be built on a flat, pile-supported deck
structure over the water. Thus, the topography is suitable for solar access.
Southern Exr~osure
The waterfront site has an unobstructed southern exposure.
Commerical high-rises to the west of the site limit southwestern exposure
after 3:00 PM during the winter and after 4:00 PM during the summer. The
proposed dimensions of on-site building bulks will partially shade each
other in the afternoon hours after 2:00 PM during the winter and late
afternoon during the summer months.
Solar Window
Sunchart photos showed there were no obstructions blocking the sun
from the east, southeast and south. There are numerous commercial office
towers to the southwest and west that will substantially block the sun
after 3:00 PM in winter and 4:00 PM in summer (See Figures 13 and 14.).

NCN

8:00 9:00 10:00 11:00 1:00 2:00 3:00 4:00

Solar -- -S

wsinol IX ( a r Solar
w i n d o wwindow
morning afternoon
limit

Fig. 13. SOLAR WINDOW, East River Landing site sunchart photo.
(Southwest corner of site looking east)

Fig. 14. SOLAR WINDOW, East River Landing site sunchart photo.
(2:00 PM blockage of sunlight in northernmost part of site)

Shading
Shading of East River Landing will occur primarily after 2:00 PM during
the winter and 4:00 PM during the summer by commercial office towers to
the west of the site. (The northernmost part of the site will be partially
shaded at 2:00 PM, and other parts of the site will be shaded later.)
Proposed buildings on the site will cast shadows on adjacent buildings in
the mid-afternoon during the winter and late afternoon during the summer.
Street Confiouration
The East River Landing street configuration was designed prior to the
study. However, the proposed street pattern will not unduly hinder solar
access protection because there are sufficient northwest-southeast streets
crossing through the site to provide adequate sunlight.
Parcel Size
[Design criteria determined parcel size. Two alternatives are provided;
Plan 1, one parcel per block (Map 8); and Plan 2, two parcels per block (Map
9). Both alternatives, though not designed under solar access siting

criteria, will not hinder the feasibility of solar access. However, with two
,parcels per block, the building bulk envelope for each parcel will be
different in height and shape than the building bulk envelope for one parcel
per block.
Buildina Orientation
Buildings are oriented in an east-west direction as much as possible so
most walls and windows face south to take advantage of available sunlight
provided by solar access zoning. Windows and walls facing northeast and

northwest will not receive direct sunlight.

uflk
Bulk conforms to proposed East River Landing guidelines. The building
bulk is derived from construction of solar envelopes, specifically "modified
solar envelopes," which, due to overall constraints of the site, allow some
shading of neighboring properties. This bulk recommended for each parcel in
Plan 1 and Plan 2 is suitable for solar access goals at this particular site.

APPLICATION
High-rises cast considerable shadows, particularly in the morning and
afternoon hours, which either must be accommodated by I) decreasing the
extent of solar access protection from south walls to rooftop levels; or 2)
restricting the hours of sunlight to 9:00 AM to 3:00 PM, or to 10:00 AM to
2:00 PM at the minimum. Sunlight is best suited for dlaylighting of interior
spaces. To apply the site criteria, a modified solar envelope has been
created to delineate possible building volume and space for development
under each alternative. The envelopes are designed to 1) prevent excessive
shading of adjacent parts of the development during the sunlight hours
specified; and 2) maximize building surfaces exposed to sunlight. The solar
envelope has been adapted to use the unobstructed sunlight over the East
River to the site. The envelope does not protect sunlight after 3:00 PM
because of existing buildings to the west of the site. Thus, no provisions
are made in the proposed envelope to preserve solar access after 3:00 PM.
The bottom seventy (70) ft., equivalent to approximately six floors, of the
high-rises in East River Landing will be shaded during the winter months.
The South Street Seaport and other public spaces will not receive any shade
from the proposed development until well after 2:00 PM. The solar envelope
maximum buildable floor area is 7.5 million square feet of floor space.

Summary of findinas for East River Landina
The following two site plans provide the street wall heights

determined by construction of solar envelopes for 1) each block as one
building bulk (Figure 15); and 2) each block as two building bulks (Figure 16).
The building bulk could be further carved to produce more than one or two

buildings within each envelope. However, the maximum building bulk is
shown by means of the southeast, northeast, northwest and southwest
corners, or solar poles at each of the corners (See Table 2 a, Table 2 b and
Table 3.). The height of each corner is provided, along with other dimensions
on site. In addition to the maximum height recommended at each corner, the
present setbacks provided by underlying zoning for land parcels are

recommended.
Below is a list of options available should implementation become

appropriate in the East River Landing area of the Manhattan Landing District.
They are as follows:
1) Incorporate guidelines for solar access as part of the New
York City Department of General Services, Division of Real
Property requirements from the New York City Private

Development Corporation when East River Landing is made
available for development.
2) Add text changes to the Zoning Resolution to provide for
parcel-by-parcel heights and setbacks within a revised Special District.
3) Add text changes to the Zoning Resolution to incorporate
parcel-by-parcel special permits.

Table 2 a. PLAN 1. PROPOSED HEIGHT RESTRICTIONS AT EACH
CORNER OF EACH BLOCK.

Block 1 Block 2 Block 3 Block 4 Block 5
Location Height in feet

Southwest 160 180 170 190 155
corner

Southeast 250 180 250 190 290
corner

Northwest 130 100 130 90 155
corner

Northeast 130 100 150 90 290
corner

Fig. 15. Each block as one building bulk.

54~
/ st~~~~~~~Y

i~~~~~'
%0 ~~(ast

�~~~~~~~~~~~~~~~~~~~~~~~~~~~~J
S~

/~~~~~~~~~~~,o
"N~~~~~~~~~~ca
Map8. LAN1 ASTRIVRLNIG
54~~~~re/

For Plan 1, heights at each corner of block parcels are provided in
Tables 2b and 3. In Table 2b, as-of-right zoning allows larger buildings
which, in turn, cast excessive shadows on neighboring properties. By
comparison, as shown in Table 2a for Plan 1, the solar envelope constraints
are shown as maximum heights at each corner of a building which covers an
entire block, and with 70 ft. of vertical shading of neighboring properties.
When the modified solar envelope constraints are compared to Table 2b,
as-of-right zoning for Plan 1, it is evident that current zoning allows larger
buildings in all cases except on Block 5. However, under as-of-right zoning,
there is shadow cast on the South Street Seaport from a building on Block 5.
If remaining air-rights were obtained from the South Street Seaport, the
building or buildings located on Block 5 could be much larger. Thus the
shadow cast on the Seaport area would be greater.
Table 2b is based upon the following zoning:
Zoning District C5-3CR, with a commercial/office building Floor Area
Ratio of 18, and a residential F.A.R. of 9, as per Z.R. Section 33-120.5;

1) Sky exposure plane, as per Section 33-432,
initial horizontal setback from property line,
narrow street = 20 ft., and wide street = 15 ft.;
Street wall height = 85 ft. or six stories;
Sky exposure plane ratio, for narrow street = 1.0 to 2.7 ft.
of vertical rise to 1 ft. horizontal setback, and
for wide street = 5.6 ft. to I ft.

2) Alternative required front setbacks, as per Section 33-442,
initial horizontal setback from property line,
narrow street = 15 ft., and wide street = 10 ft.;
Street wall height = 85 ft. or six stories;
Sky exposure plane ratio, for narrow street = 3.7 to I ft., and
for wide street = 7.6 to I ft.

Note: For development under "tower" zoning, there would be no height
restriction if a building occupies only forty (40) per cent of its site.

Table 2 b. PLAN 1. COMPARISON OF PROPOSED HEIGHT
RESTRICTIONS AT A GIVEN SETBACK FROM CORNERS OF EACH
BLOCK UNDER AS-OF-RIGHT ZONING (F.A.R. 18).

Block 1 Block 2 Block 3 Block 4 Block 5

Location Area in square feet

Block size: 55,000 33,825 64,500 62,350 37,700
Floor area: 990,000 608,850 1161000 1122300 678,600

Southwest corner, Distance in feet
setback &
sloped
setback: 10 &7.6/l 10 &7.6/1 15 &3.7/1 10&7.6/I 15&3.7/I

Allowable
height: 300 206 403 404 261
................................... ................................................*....... ................ ................... ............
Southeast corner,
setback &
sloped
setback: 10&7.6/1 10&7.6/1 15&3.7/1 10&7.6/1 15&3.7/1

Height: 300 206 403 404 261

Northwest corner,
setback &
sloped
setback: 10&7.6/1 15&3.7/1 10&7.6/1 15&3.7/1 10&7.6/1

Height: 300 211 393 395 256
................................................... ............... ..... ...............,* , , ,........* ...... ........ ....... ..................
Northeast corner,
setback &
sloped
setback: 10&7.6/1 15&3.7/1 10&7.6/1 15&3,7/1 10&7.6/1

Height: 300 211 393 395 256

/ /~~~~~~~~~~~~~P

pip /1

;iN~Tb, X~C�/ ,��

Ile~~~~~~~~~~~ soGo
k~~~~>~:

4~~~~~~~~~a 9/ PLA 2,E S IERLNIG
58~ //~ 4Py)

Example:
Block 1

Fig. 16. Each block as two building bulks.

Table 3. PLAN 2. PROPOSED HEIGHT RESTRICTIONS AT EACH
CORNER OF EACH BLOCK

Block I Block 2 Block 3 Block 4 Block 5

Location Height in feet

So uthwest
corner 220 280 225 75 225

Southeast
corner 220 280 300 140 420

Northwest
corner 75 145 125 75 225

Northeast
corner 75 145 125 140 225

Block 6 Block 7 Block 8 Block 9 Block 1 0

Southwest
corner 75 300 110 240 75

Southeast
corner 170 300 75 340 190

Northwest
corner 75 120 75 240 75

No rth east
corner 170 120 110 340 190

Note: No portion of a building should pierce any of the sloping
"rooftop" planes which are constructed by connecting the heights
at each corner of block parcels.
6 0

As-of-riaht zonina
The East River Landing site is currently a part of the Special Manhattan
Landing Development District, a Special Purpose District under Section 98
of the Zoning Resolution. The Floor Area Ratio (F.A.R.), the ratio between lot
area and allowable floor area that can be built on a lot, is a mnaximum of 18.0
for C5-3CR, the predominant zoning designation for the East River Landing
site. The residential F.A.R. is limited to 9.0. Sky exposure planes are
determined by provisions under Section 33-432 of the Zoning Resolution,
with "Alternate Required Front Setbacks" provided under Section 33-442.
In Z.R. Section 98-171, a provision exists for sunlight to reach
pedestrian space, but the pedestrian space which is shadowed by adjacent
buildings such as those along Marginal Street or the future East River
Landing are excluded.
Under Special Purpose District zoning, air-rights may be transferred
from a low-density site such as the South Street Seaport to an adjacent
site. However, the new building at the adjacent site cannot exceed an F.A.R.
of 21.6.
At present there are no Special Purpose District zoning provisions
which will help protect solar access at the South Street Seaport located to
the north and northeast of East River Landing. The air-rights above the
Seaport can be purchased for transfer to adjacent properties. Although this
maintains the Seaport's scale, character and height of buildings within its
site, neighboring buildings would grow much larger, robbing the Seaport's
sunlight.

Benefits of conventional zonina
As-of-right zoning permits an F.A.R. of 18 which would allow more
square footage of floor area in a building as compared to a building
constrained by the solar envelope, or specifically the modified solar
envelope (See Appendix 2.). With alternate setbacks and bonuses obtained by
the developer of an East River Landing building, an additional F.A.R. of 3.6 is
possible. Approximately twenty (20) per cent of additional square footage
of floor area would be allowed, resulting in six to eight additional stories.
As shown in Table 2b, the square footage of floor area under conventional
zoning would be increased by approximately twenty (20) per cent for each
block.
Benefits of solar access
Although less floor area would result, the benefit of natural lighting
would be the main advantage of solar access. As will be discussed in
Section 4 following, the economic payback is long for passive solar
strategies, but the energy savings and quality of life in the workplace or in
residences are nonetheless substantial.
The public benefit of solar access to the South Street Seaport is
difficult to estimate in strictly economic terms, but the impact upon the
Seaport due to excessive shading by future buildings built under
conventional zoning can be lessened. Solar access would guarantee ample
sunlight to an important historic place and open space benefits to the public
at large.
Solar zoning would protect adjacent properties as well. Neighbors
would receive much less shadow under solar zoning than under conventional
zoning. This is evident when the modified solar envelope methodology is
applied to each block. The solar envelope is modified because it is

determined by the existing surroundings and site conditions, and it is
increased uniformly in height which limits the shadow cast on neighboring
buildings to be only seventy (70) feet on March 21 and September 21. To the
west and northwest of East River Landing the adjacent properties have
buildings whose loading platforms and service functions occur on the lower
floors facing the East River Drive and the East River Landing site. The
seventy ft. vertical shadow cast on these lower floors under solar access
would be far less than the shadow cast by larger buildings built under
conventional zoning.

SECTION 4
ECONOMIC IMPACT OF PROVIDING SOLAR ACCESS

This section evaluates the economic benefits of using solar energy in
New York City. The economic analysis is broken down by categories:
low-rise residential passive solar, low-rise residential passive solar,
high-rise commercial passive solar, and photovoltaic solar energy.
Passive solar space heating is the most efficient method of harnassing
the sun's energy. Passive systems such as greenhouses or sunspaces (See
Section 1.) are cost effective for heating low- or high-rise residential
buildings, when used with energy conservation techniques. For high-rise
buildings, apartments which face south can make effective use of
greenhouses or sunspaces, unlike those apartments which face north.

Low-rise Residential Passive Solar
Brookhaven National Laboratories and the U.S. Department of Energy
(DOE) monitored a specially designed and constructed solar house. The house
is a two-story, 1500 sq. ft. home, situated in a climate similar to that of
New York City. By using energy conservation measures and passive solar
energy, the house consumed less than one-third of the energy normally
required to heat a conventional house (See Table 4.).

Table 4. ENERGY CONSERVATION COMPARISON OF CONVENTIONAL
HOUSE TO BROOKHAVEN HOUSE.

Annual consumption Conventional house Brookhaven house

Heating oil 675 gallons 175 gallons

Electricity (Data not available) (Data not available)

Payback period 3 to 4 years 8 to 1 0 years

Total energy savings 70 per cent

Note: The Brookhaven House is continually monitored, and savings
are slightly different each year. The savings given above occurred
in 1982-83. Recent savings appear to be even greater.

Economic projections in this study are based upon the "simple payback"
method in which the capital cost is divided by the annual savings to find the
number of years necessary to pay back the capital cost. Other methods
include "present worth" and "discounted rate of return." However, in
projections for three to four years ahead, simple payback is as accurate as
the other methods. Furthermore, these energy measures would not be
implemented unless they have the shorter paybacks (i.e. 3 to 4 years); the
simple payback method is appropriate. The other methods are dependent
upon forecasting of inflation and fuel costs, and since prior studies based on
these methods have often not been validated, they may be less predictable.
At ~~ To assess the contribution of passive solar, a conventional residential
unit without passive solar must be compared to a residential unit which is
first retrofitted for energy conservation and then for passive solar, as
follows in Table 5:

Table 5. ANNUAL COMPARISON OF COSTS AND SAVINGS.

COSTS SAVINGS

Conventional Energy Passive Energy Passive Passive
house, conser- solar conser- solar solar with
annual vation retro- vation energy
consumption applied fitted & conser-
data to annual applied to vation *
data annual data

Space heating (gas):
$ 1200 $ 720 $ 600 $ 480 $ 120 $ 600

Domestic hot water:
240 120 120 120 --- 120

Lights & appliances:
500 400 370 100 30 130

Air conditioning:
150 75 75 75 --- 75

TOTALS $ 2090 $ 1315 $ 1165 $ 775 $ 925

� Note: A passive solar house, as widely defined in design and in contemp-
orary construction, has energy conservation measures, such as ample in-
sulation along with its passive solar features.
Analysis:
Savings from energy conservation: $ 775

Savings from passive solar: 150

Estimated capital costs,energy conservation 7000

Estimated capital costs, passive solar: 3000..
$10,000

Analysis,
continued: Energy conservation payback: $ 7000
= 9 years
775

Passive solar payback: $ 3000
= 20 years
150

Payback with energy conservation
and passive solar combined
(simple payback): $10,000
= 10 years
925

Insulation, whether installed by itself or provided in combination with
passive solar features in a building, must be used in accordance with the
local climate of New York City. Too much insulation entails a long payback
period. The following summary of the actual role insulation plays supports
the findings from Table 5:

Table 6. DIMINISHING RETURN OF INSULATION.
Annual BTU Increased Annual Years for
savings per cost per dollars simple
sq. ft. of sq. ft. savings payback
insulation per sq.ft.

Amount of
insulation by
thickness in
inches:

3 1/2 to 6 3120 $ .16 $ 3.14 5.2

6 to 9 1/2 180 .22 1.84 12.2

9 1/2 to 12 720 .16 .70 22.8
67

The annual space heating cost savings were based on increased
insulation in the walls and roof, reduced air infiltration due to tighter
windows and doors, proper orientation of house to maximize passive solar
energy, correct window size and thermal mass to absorb daytime solar heat
gain for nighttime heating. Annual electrical costs were reduced by
installing energy-efficient appliances such as refrigerator, air conditioner
and laundry equipment, and by utilizing energy-efficient lamps. Domestic
hot water costs were reduced by installing low-flow sink faucets,
insulating jackets on the domestic hot water storage tank, using low-flow
shower heads, and lowering the water temperature.

Low-rise Residential Active Solar
(Solar Domestic Hot Water Heating)

Based upon the survey data (See Appendix 1.), solar domestic hot water
heating was not cost effective. Tax credits from the federal government
and the State of New York covered 40 and 15 per cent, respectively, of the
installation costs. The solar domestic hot water installation showed a
simple payback of more than twenty (20) years, approaching the life of the
solar equipment estimated at twenty-four (24) years. Simple payback was
based upon present day fuel costs. If energy costs escalate in the future,
then the payback will be shorter; if energy costs decline, the payback will
be longer.
Brooklvn Union Solar House case study
The evaluation of the Brooklyn Union Gas solar house confirms that the
solar domestic hot water heating is not economnically viable at present. The
Brooklyn Union Gas solar house case study is summarized in Table 7. Data

from this study indicates that solar energy systems for domestic hot water
heating results in an average savings of forty-seven (47) per cent of
approximately $ 145.00 per year. The financial cost of the installation was
$ 5000. The simple payback was thirty-two (32) years, which exceeds the
expected life of the solar equipment (24 years). Maintenance costs range
from $ 25 to $ 50 per year, thus lengthening the payback period.

Active Solar Space Heatina
Based on the analysis of solar domestic hot water heating, active solar
space heating would be even less cost effective since the collector cannot
be used effectively year-round. Domestic hot water systems do provide
substantial percentages of -- if not all -- hot water needs in summer
months and do operate in winter, while active solar space heating is
unnecessary in summer and has been found to contribute a small percentage
of what is needed in winter.

Table 7. MONITORED RESULTS, THE BROOKLYN UNION GAS SOLAR
HOUSE'S HOT WATER HEATING.

Solar energy system monitored by Brooklyn Union Gas, Brooklyn,NY

Site location: 62 Jacques Avenue, Staten Island, NY
Solar collector svstem data Manufacturer: Ametek
No. of panels: Four (4)
Size of panel: 30 sq. ft.
(estimated)
Storage tank: 120 gallons
Number of persons living in solar house: 3 or 4

Month and year Gallons Total Energy Per cent
used energy provided solar
used in by solar
BTUs in BTUs

March 1983 1945 1593000 826000 48
April 1983 2162 1330000 492000 63
May 1983 2330 1275000 389000 69
June 1983 1544 823000 67000 91
July 1983 1448 790000 28000 96
August 1983 1775 858000 47000 94
September 1983 2101 927000 67000 92
October 1983 *high 2370 1149000 463000 59
November 1983 1568 1132000 640000 43
December 1983 1569 1449000 1055000 27
January 1984 *low 1180 1328000 1094000 17
February 1984 1302 1416000 1100000 22
March 1984 1551 1569000 1100000 29
April 1984 2017 1497000 800000 46
May 1984 2062 1130000 500000 55
June 1984 1770 940000 150000 84
July 1984 1760 970000 250000 74
August 1984 1585 766000 100000 86
September 1984 2030 910000 150000 83
October 1984 1998 1000000 500000 50
November 1984 1942 1069000 650000 39
December 1984 1675 1217000 920000 24
January 1985 1410 1375000 1100000 20
February 1985 1518 1382000 950000 31
March 1985 1719 1453000 800000 44
April 1985 1807 1133000 500000 55

Totals 46,138 30,481,000 14,738,000 47 %

Hiah-rise Residential Passive Solar
The ability of high-rise apartment buildings to benefit from passive
solar access is limited by their access to solar energy. If a building's
south-facing apartments have terraces, the terraces can be enclosed in
glass to form a sunspace/greenhouse which can produce heat in the winter.
North-facing apartments are limited in the amount of extra heat derived
from the sun, and the extra heat which may be obtained in south-facing

apartments is not easily distributed to north-facing apartments.
High-density residential active solar faces the same problems as
low-density residential active solar.
The cost of a sunspace/greenhouse may vary considerably, but it is
estimated as approximately $14,500 for a 17 ft. x 6 ft. glass enclosure. The
savings obtained may range from $ 500 to $ 1200, and assuming an average
savings of $ 850, the simple payback is as follows:
Cost of sunspace glass: $ 14,500

=- 17 years
$ 850

Hiah-rise Commercial Passive Solar
The main energy demand of commercial high-rises is for light and
air-conditioning. Passive solar design can be used to minimize the amount
of artificial light required by offices.
High-density commercial active solar faces the same problems as does
residential active solar. Low-rise commercial does not exist as a land use
in the two selected sites; thus, low-density commercial passive solar
energy was not studied.

The lighting load for a typical office building is five kilowatts per sq.
ft. per year or more. Studies by I) the Ehrenkrantz Group for the New York
State Energy Office, and 2) the Tishman Realty and Construction Company
show electrical consumption savings from solar "daylighting" and energy
efficient lighting. (For comparable studies, the General Proceedings of the
annual International Daylighting Conference provide additional information.)
The Ehrenkrantz Group measured the lighting load available from highly

efficient lighting equipment, which provides 85 footcandles of light, and
found the energy consumption to range from 2.4 to 2.5 watts per sq. ft.
Tishman's evaluation of a new office building, Park Plaza in Newark,
indicated that lighting represented about 25 per cent of the total energy
consumption and about 45 per cent of the total when computers and
computer-related loads were subtracted. Automatic controls that turn
lights on and off by responding to occupancy of each space, provide 50 per
cent and more savings in lighting energy consumption. Thus the lighting load
can be reduced, ranging from 2.5 to 3 watts per sq. ft., by conserving energy.
The Ehrenkrantz Group further projected that passive solar utilization
through daylighting would produce approximately 50 per cent savings beyond
those savings accrued from energy conservation. The reduced load due to
solar contribution to lighting is I to 1.5 watts per sq. ft. whenever the space
is being lighted (1800 to 2000 hours per year), at least within an area
comprising 15 to 20 feet in depth around the periphery of an office building.
Skidmore Owings and Merrill designed the Irving Trust Bank building for
the bank's computer facilities to achieve a similar load due to daylighting.
Without task lighting (lighting which directly affects a person's immediate
desk work area) and with a completely sufficient light level of 55
footcandles evenly distributed throughout the space, plus the contribution of

daylighting, the load is 1.3 watts per sq. ft. (Comparable loads sought under
conventional design of energy conserving office buildings range from 2.5 to
2 watts per sq. ft.)
Table 8 demonstrates the economic benefit of reducing energy
consumption due to artificial lighting and the relative impact of daylighting.
The tabulation is based upon the assumption that a new energy efficient
building with daylighting will omit the daytime use of artificial lighting at
the periphery of each floor, which constitutes approximately twenty (20)
per cent of the total floor area. The connected light load of the
non-peripheral interior would likely be reduced from 3 watts per sq. ft. to 1
watt. At the perimeter, the reduction would be even greater. The result
would be approximately 0.4 watt per sq. ft. for an entire floor multiplied by
2000 hours of use per year equals 800 watts or 0.8 kilowatt.

Table 8. COMPARISON OF SAVINGS BETWEEN CONVENTIONAL
OFFICE BUILDING AND DAYLIGHTED OFFICE BUILDING.

Conventional office New office building
building with daylighting from
Annual consumption passive solar

Electrical energy for 1.0 to 3 kilowatts/ .50 to 1.5 kilowatts/
artificial lighting sq. ft./year sq. ft./year

Cost of electrical energy $1.50/sq. ft. at $1.50/sq. ft. at
perimeter perimeter

Capital costs Assuming $3.00 as Assuming $6.00 at
an average cost for perimeter area, yet
lighting installation will be lighting twice
at the perimeter of as much area from
a floor sunlight

The savings and simple payback can be projected as best case and second
best case, as follows:

Best case: For daylighting strategies such as "light
shelf" ( bounces sunlight to the interior),
etc., the most that can be saved would be
$1.50/sq. ft. at the perimeter and an addi-
tional $1.50/sq. ft. for an adjacent interior
area equal to the perimeter area.

$ 6.00 for daylighted building
- 3.00 for conventional building
$ 3.00 differential capital cost

divided by $ 3.00 savings per year = I year
payback

Next best case: For daylighting strategies, assumed savings
would be $.75/sq. ft. at the perimeter and an
additional $.35/sq. ft. for an adjacent
interior area equal to the perimeter area;
equals a total of $ 1.15 savings.;

$ 3.00 differential capital cost

divided by $ 1.15 savings per year = 3 years
payback

To assess the impact of passive solar for high-density areas, a typical
existing office building without state-of-the-art, energy-efficient features
was compared to a new office building with energy-efficient features and
daylighting but not passive solar heating.

The following considerations are taken into account in assessing the
dollar value of the impact of energy conservation and passive solar in
high-rises:
I. An energy-conserving building cannot be actually separated from a
passive solar building. The energy conservation design of the building
envelope (or skin), its orientation, its plan, its windows and other materials
is inherent in a passive solar high-rise.
2. Energy conservation measures can be identified that are not closely
related to passive solar; for example, more efficient lamps, boilers, air
conditioning chillers, cooling towers, heat exchangers, daylighting timers to
switch off artificial lighting when unneeded, and dimmers.
Economic impact is best projected by comparing the energy
consumption measured in British Thermal Units (BTUs) per sq. ft. per year,
as follows in Table 9:

Table 9. COMPARISON OF ENERGY CONSUMPTION.

Conventional office Office building with Office building with
building energy conservation passive solar (with
(without daylighting) daylighting and
energy conservation)

160,000 BTU/sq. ft./yr. 55,000 to 78,000 35,000 to 40,000
BTUs/sq. ft./year BTUs/sq. ft./year

Note: BTU is British Thermal Unit,the energy required to raise a pound of
water one degree Fahrenheit in the temperature range between 62 and 63
degrees Fahrenheit.

The impact of ohotovoltaic systems
Photovoltaic solar systems convert sunlight to electricity.
Consolidated Edison (Con-Ed) is currently monitoring the photovoltaic
experiment at the Citicorps Building in New York City. The project was
jointly funded by Empire State Electrical Energy Research Corporation
(ESEERCO) and Con-Ed. The purpose of the research was to evaluate on-site
performance of an installed photovoltaic system in New York City. Adjacent
to the photovoltaic panels, a weather station measures the solar energy per
square foot.
The facility has a gross collector area of six hundred sq. ft. Each I ft.
x 4 ft. panel is composed of 35 single circular crystal cells. The net area of
cells is 450 sq. ft. The cells are manufactured by Atlantic-Richfield (ARCO)
and were installed in April, 1983.
The photovoltaic cells have a system efficiency of ten (10) per cent;
the estimated overall system efficiency is five to six per cent. The
efficiency includes DC (direct current) to AC (alternating current)
conversion. AC currents are supplied in offices and homes. This means that
for every BTU of thermal energy from the sun, five to six per cent is
converted to electricity at the point of use; in this case, at the office
building.
The peak installed capacity at the office building site is five kilowatts
(equal to 5000 watts) with a generating capacity of 4300 kilowatt hours per
year. Although the facility is for experimental purposes and the capital
costs much greater than a large-scale installation, the photovoltaic system
cost ranged from $14 to $20 per peak watt installed. (A peak watt is the
maximum electrical energy produced on a sunny day at noon.) The
calculations in Table 10 show over a century-long payback period, thus

making photovoltaics unmarketable at this time. Technological advances in
photovoltaics might lead to a more favorable economic payback in the
future.

Tablel 0. PHOTOVOLTAICS.

Generating capacity of 4000 to 4300 kilowatt hours, yielding five
kilowatts or 5000 watts per year, multiplied by the cost per peak
watt installed:
5000 watts x $ 14 = $ 70,000

5000 watts x $ 20 = $100,000

Value of electricity generated:

4000 kilowatt hours x $.15/kilowatt = $ 600 savings

4300 kilowatt hours x $.15/kilowatt = $ 645 savings

Cost divided by value of electricity:
$ 70,000 $ 100,000
= 117 years = 155 years
$ 600 $ 645

Conclusiom
Based upon this study, passive solar energy is effective in low-rise
residential and high-rise commercial buildings. For low-rise residential
buildings, a single family home can save two-thirds to three-fourths of the
energy normally consumed by using passive solar energy and energy
conservation measures. High-rise commercial buildings can achieve
substantial savings through the use of daylighting techniques.
Active solar energy and photovoltaics in all applications for New York
City were found to be uneconomical. Passive solar energy has the shortest
payback period and is the most viable alternative to fossil fuels.

SECTION 5
LEGAL EVALUATION FOR SOLAR ACCESS

This section evaluates the various legal methods that have been
successfully implemented in other parts of the country, such as solar
easement, solar covenant, and solar permits, to protect solar access. The
focus will be on legal alternatives for solar access for New York City, such
as normal height and setback controls, and solar zoning. The following
questions were chosen to evaluate current legal possibilities for solar
access protection:

1. How successful have solar easements and covenants been in
implementing solar access?

2. Will solar envelopes be construed as an unconstitutional
taking of property without due process under the U.S.
Constitution?

3. How can zoning implement solar access?

Landowners have a legal right to sunlight falling perpendicularly on
their land, for a man is said to own his property "from the center of the
earth straight up to the heavens," (Prosser, Law of Torts, Sec. 13).
However, landowners in the United States have no right to receive solar
energy that would reach their land only after slanting across property owned
by others.

Private sector aDoroaches
Private sector approaches such as easements and covenants are
allowed in a number of states. Owners of solar facilities may want a right
to receive sunlight across adjacent land. The alternatives are outright
purchase of adjacent property, purchase of airspace over the property, or
purchase of an easemnent for light across the property. The first two
solutions are expensive in most situations. An easement is a property right
in land belonging to another, and the creation of an easement requires legal
formalities. It cannot be revoked or terminated at will, although it may be
limited to a specified time. In an affirmative easement, for example a
right-of-way, the purchaser has a right to enter the land of the seller to the
extent specified in the easement. In a negative easement the purchaser does
not acquire the right to enter the seller's land, but the seller is restrained
from doing something an the land that would be allowed if the easement did
not exist. An easement for light is a prime example of a negative easement.
The purchaser of the negative easement cannot enter the land restricted by

the easement (restricted land) but can prevent the landowner who is
restricted from interfering with the passage of light according to the
easement forms. For example, the easement owner for light could seek a
court order to remove obstructions that exceeded the height stated in the
easement. Thus, the purchaser is assured of receiving lateral light to the
solar facility. Negative easements, including easements for lights, must be
negotiated among the parties. In urban areas, the easement cost would be
high because it would limit vertical development that accounts for much of
the land value. The costs and difficulties of negotiating satisfactory
agreements between property owners could limit the appeal of easements.

The major advantage to solar easements is that they are usually
permanent and consequently "run with the land." They also require minimal
government involvement and are not affected by zoning changes on adjacent
property.
Solar easement use is simple in theory yet complex in an urban setting.
Even if the parties voluntarily agree to such restrictions, the restriction of
developable airspace over several lots to the south of a solar facility may
be prohibitively expensive. One could envision a complex set of restrictions
where owners are not sure when a violation has occurred. Multiple
restrictions would complicate title companies' ability to certify clear title
as well as realtors' ability to determine the buildable area of a lot.
For new subdivisions, restrictive covenants may be more useful than
solar easements. A covenant is an agreement among parties which acts as a
deed restriction. Developers can insert covenants protecting solar access in
deeds to new buyers, binding lot owners. In fact, some communities grant a
density bonus for the filing of a restrictive covenant against shading from
direct sunlight under their planned unit development (PUD) provisions; (for
example, Lincoln, Nebraska, Design Standards for Zoning Regulations,
adopted in 1979).
Covenants possess the same potential problems as easements because
they both depend on numerous agreements to guarantee solar access.
The other alternatives to private agreements are zoning and
governmental mechanisms to guarantee solar access. In the United States,
Oregon and Maryland now authorize municipal laws protecting and assuring
access to incident solar energy. Other states including Arizona, Michigan
and Illinois are currently considering similar action. The State of New York
amended the zoning enabling statute to provide that zoning regulations of

cities, towns and villages may consider solar energy. The statute stipulates
that municipal zoning regulations could be designed, in part, "to make
provision for," so far as conditions may permit, the accommodation of solar
energy systems, equipment and access to sunlight (General City Law, 20).
Solar zoning must not conflict with the federal constitution. The
Fourteenth Amendment prohibits any state from depriving persons of
property without due process and prohibits states from denying equal
protection of the law. Use restrictions on real property must be reasonably
necessary to achieve a substantial public purpose. When a property owner
challenges a zoning ordinance, the court decides if the restrictions can
reasonably be deemed to promote community purposes, and will include
consideration of the treatment of similar parcels.
Solar zonina
Local governments that implemented solar zoning are Davis and Century
City in California; Colorado Springs, Pilken and India County in Colorado;
Albuquerque and Los Alamos in New Mexico; Largo, Fonida; and most recently,
Portland, Oregon. In solar zoning, municipalities define "solar zones" in
which solar use is encouraged. Solar use may be compatible with a variety
of neighborhoods, including commercial, industrial, or residential areas.
Solar zones may be overlaid on existing zoning. Existing zoning categories
such as general commercial or residential are not altered or replaced, but
defined portions of appropriate zones are given an additional solar
classification. Exemptions may be granted for individual lots, or for groups
of lots which are planned together for an energy efficient layout.

All new construction in solar zones could be subjected to strict height
and spacing controls to minimize shading of neighboring properties.

For several years, Los Alamos, New Mexico, has used a
prior-appropriation by permit approach. The ordinance is a zoning
amendment that protects solar collectors from shading by a hypothetical
twelve-foot fence at the lot line between the hours of 10:00 AM to 3:00 PM,
provided that the solar collector is not greater than one-half the floor area

it serves. The ease of application of the permit makes it a viable tool for
protecting solar access. A drawback is that the municipal permit required

to vest rights under this strategy sounds like a rezoning. To be upheld
against an opponent whose development options are restricted, the due
process accorded a rezoning may be necessary, such as public hearings,
notification, and registration.
Larae developments
Special kinds of flexible municipal laws are used to control large
developments that offer innovative approaches. One such law is bonus
zoning where a landowner receives the right to incremental increase of
property in exchange for providing a public amenity. This is often used to
obtain public open spaces without cost to the city and could be adapted to
procure solar use in the development or minimize shading to neighboring
properties.
Cluster zoning could permit a developer to group buildings near the
northern edge of the property and to aggregate the required open space to

the south. Access to both direct and reflected sunlight would be protected
to some degree by the southerly open space; the grouped buildings would
require less heat by protecting each other from the elements.

Advantaoes of solar zonina
1. Zoning is an effective regulatory tool for land use planning. The
addition of "solar zones" could be incorporated into existing zoning laws and
would not add significantly to municipal burdens.
2. Potential solar users would know before deciding whether or not to
install a solar device, whether their property was located in a "solar zone"
and, if so, the nature and extent of the protection which they would receive.
3. In passing zoning laws, cities are in a good position to weigh the
competing interests of both potential solar users and their neighbors and
are likely to limit their restrictions to those which are reasonable for all
parties. Such restrictions may mean, for example, that access is provided in
some areas to permit only solar hot-water heating and not space heating, or
that no protection would be provided in areas expected to develop densely.
4. Solar zoning does not permanently freeze land use, as cities retain
the right to amend all laws in response to changes in local conditions.
5. Adequate enforcement of the solar right would generally occur when
new development is planned, since building permits should not be issued for
buildings which would contravene zoning laws.

Disadvantaces of solar zonina
I. Solar zoning is not a secure protection of solar access, as laws may
be changed at any time.
2. Zoning cannot be established or enforced by individuals but only by
the city and, therefore, provides no protection for isolated solar pioneers.
3. Solar zoning can be only partially successful in existing areas, as
structures cannot be moved to meet new requirements.

Solar zoning offers the best means of integrating solar rights with
land-use planning. The cost of solar easements is likely to be high for
airspace over urban property. The voluntary nature, along with the expenses
and complexities, of restrictive covenants or solar easements offer no
benefits over the solar envelope zoning in urban areas. Restrictive
covenants seem most appropriate in large-scale developments through
imposed deed restrictions on all buyers.
Private alternatives are attractive only when conceptually simplified
and applied to low-density development. To protect solar access for a
single lot, several lots to the south must be restricted by solar easements.
Multiply this easement requirement by several lots, and the result is
multi-layered restrictions over those lots. The restricted lot would have
the same amount of buildable area allowed by the multiple easement
restrictions that would be very similar in shape and volume as a solar
envelope.
Solar zoning achieves the desired results of solar users without the
expense, complexity and time consumption required for restrictive
easements or deed covenants.

SOLAR ACCESS STUDY SUMMARY OF FINDINGS

Numerous local governmental bodies around the country are
investigating the potential for solar energy to replace fossil fuels as an
energy source. One of the prerequisites to achieve this goal is the
protection of direct sunlight to solar facilities. The most effective and
efficient way to preserve people's opportunity to receive sunlight is through
Solar Access Control.
Siting criteria were developed to determine what areas are suitable for
solar energy use and how these areas can be enhanced to take even more
advantage of the sun's free energy. The siting criteria (See Section 2.)
incorporated land-use, transportation, and building bulk elements to
maximize the availability of sunlight to dwellings and buildings.
A methodology (See Section 2.) was developed to incorporate the siting
criteria into a uniform application procedure called the Solar Envelope. The
solar envelope was based upon geometric angles and dimensions to satisfy
the siting criteria's qualifications.
Thus the two selected sites -- Annadale-Huguenot, Staten Island; and
East River Landing, Manhattan -- were evaluated by the siting criteria and
reconfigured by the solar envelope. The result was a workable development
of homes and buildings that were achievable under Solar Access Control.
The investigation of solar energy economics was based upon the
payback periods of the solar energy equipment. The payback period refers to
the length of time investors of solar energy facilities would have to wait
before receiving a full return on their investment in energy-saving
equipment or building features. The payback periods comparing solar energy

equipment to conventional energy systems for both a hypothetical
homeowner and commercial developer were computed in Section 4.
In both test situations, the payback periods in all categories of solar
use -- except for low-rise residential passive solar and for new high-rise
passive solar daylighting -- were longer than those for conventional energy.
Al Therefore, a hypothetical homeowner and commercial developer would find
conventional energy sources more economical than solar energy and would be
unlikely to invest in solar energy facilities.
Although, in general, solar energy is less economical than conventional
energy sources, other considerations make solar energy use attractive.
First, the building features of low-rise residential passive solar can be
easily incorporated in the initial construction of homes, the additional cost
largely consisting of additional materials such as extra masonry to provide
thermal mass. Second, although active solar systems are not economical at
the present, some solar heating for residential and commercial buildings
may have payback periods sufficient for some property owners. Third, solar
domestic hot water heating is an attractive investment when utility
electric rates are high. Fourth, use of solar energy would reduce New York
City's reliance on fossil fuels, which is particularly important in the face of
changing world conditions and fluctuating oil prices. Furthermore, unlike
conventional energy sources, solar energy does not contribute to air
pollution. Finally, solar energy can lower the demand placed upon
conventional utilities by energy consumers.
Solar Access Control is an effective and useful way of preserving
property owners' access to direct sunlight. Current economic conditions,
coupled with the relatively high cost of installing and operating solar
energy equipment in comparison to other energy sources, produce an

unfavorable investment condition for the average person living in New York
City. A monitoring of economic conditions and the ongoing advancements in
solar technology will enable the city, when the appropriate opportunity
arises, to act --thus encouraging the use of solar energy in New York City.

BIBLIOGRAPHY

References:
1 Thomas, William; et al. Overcomina Leaal Uncertainties About
The Use of Solar Enerav Systems. Chicago, Illinois:
American Bar Foundation, 1978.

2 Hayes, Gail Boyer. Solar Access Law: Protectina Access To
Sunliaht For Solar Enerav Svstems. Environmental Law
Institute. Prepared for the Office of Policy Development
and Research, U.S. Dept. of Housing and Urban Development,
and U.S. Dept. of Energy. Cambridge, MA: Ballinger Publish-
ing Co./Harper & Row, 1979.

3 Jaffe, Martin; and Duncan Erley. Site Plannina For Solar Access:
A Guidebook For Residential DeveloDers And Site Planners.
Chicago, Illinois: American Planning Association, 1979.
Available from U.S. Government Printing Office, Contract
H-2573; or from the American Planning Association, 13113.
East Sixtieth St., Chicago, IL. 60637.

Protectina Solar Access For Residential DeveloDment: A
Guidebook For Plannina Officials. Availability same as
above.

4 Knowles, Ralph L. Solar Envelooe Zonina: AoDlication To The
Citv Plannina Process. Los Anaeles Case Studv. Golden,
Colorado: Solar Energy Research Institute (SERI), 1617
Cole Blvd., Golden, CO 80401; June, 1980. Available from
SERI.

Solar Envelooe Conceots: Moderate Densitv Buildina Aooli-
cations. Golden, CO: SERI, April, 1980. Availability same.

5 Knowles.
Enerav And Form: An Ecoloaical Aooroach To Urban Growth.
Cambridge, MA: M.I.T. Press, 1974.
Also see:
Sun Rhvthm Form. Cambridge, MA: M.I.T. Press, 1981.

Knowles, continued.

Also see:
6 City of Los Angeles.
Park Mile Plan. City of Los Angeles Dept. of Planning.
Development map and brochure, 1984; and case study,
Wilshire Boulevard Office Buildina. City of Los Angeles
Dept. of Planning. Solar envelope and building plans
constrained by the solar envelope, 1984-85.

7 White, C. Stuart; Banfield White & Arnold, Inc., Architects;
and Alvin 0. Converse, Dartmouth College. A Case Study
Of The 424 West 33rd Street Aoartment House. Upton,
NY; and Washington, DC: Brookhaven National Laboratory,
Associated Universities, Inc.; and U.S. Dept. of Energy,
July 1981. Available from the National Technical Infor-
mation Service, U.S. Dept. of Commerce, 5285 Port Royal
Road, Springfield, VA 22161. Document No. BNL 51422.

8 Frank, Lynn; Director; John Kaufmann; and Henry Markus.
Solar Access Tool Kit. Salem, OR: Oregon Dept. of Energy,
March 1985. Available from Dept. of Energy, Labor and
Industries Bldg., Room 102, Salem, Oregon 97310.
Telephone: 503-378-4040; toll free, 800-221-8035.

9 Rouse, Roland E. Passive Solar Desian For Multi-Familv
Buildinas Case Studies And Conclusions From
Massachusetts' Multi-Family Passive Solar Proaram.
Boston, MA: Commonwealth of Massachusetts, Executive
Office of Energy Resources, January 1983. Available from
the above office, 100 Cambridge St., Boston, MA.
Telephone: 617-727-4732.

10 Bosselmann, Peter; et aL. Sun And Liaht For Downtown San
Frano.Qis. Environmental Simulation Laboratory, Institute
of Urban & Regional Development, College of Environmental
Design, University of California, Berkeley, CA 94720,
1983.
Available from the Environmental Simulation Laboratory.
Telephone: 415-642-2961, or 642-3208.

11 Porter, Brent M.; and William C. Whyte. Simulation of existing
conditions and impact of proposed development upon
Greenacre Park, East 51st St., NYC; model simulation,
graphic projection, and computer processing, 1983.
Research for the Greenacre Foundation, Rockefeller Center,
NYC. Presented to the City of NY Board of Estimate, 1983.

Also see:
Porter, et aL "Precedent For Sun Rights In New York City,"
Proceedinas. Seventh National Passive Solar Conference,
Knoxville, Tennessee,1982; pp. 617-622.

12 Whyte, William C.; et al. Greenacre Foundation, Rockefeller
Center, NYC, May, 1987.

Additional references:

Olgyay, Victor. Desian With Climate. Princeton, NJ: Princeton
University Press, 1963.

Moon, P. "Proposed Standard Solar Radiation Curves for
Engineering Use," Journal of the Franklin Institute, Vol.
230, No. 5 (November 1940), pp. 4-7.

Hand, Irving F. "Charts to Obtain Solar Altitudes and Azimuths,"
Heatina and Ventilatina Journal, (October 1948), pp. 86-88.

Libby-Owens-Ford Glass Company. Sun Anale Calculator. Toledo,
Ohio: L.O.F. Inc., 1950 to present.

Mazria, Edward. The Passive Solar Enerav Book. Emmaus, PA:
Rodale Press, 1979, 1987.

DiDonno, Ronald; project director; et al. Energy Conservation
Potential In Low-rise, High-density Housing. Prepared for
New York State Energy Research & Development Authority.
Albany, NY: NYS ERDA, 1980. Contract No. 42/EU-RCU/79.

APPENDIX 1

INVENTORY OF SOLAR FACILITIES IN NEW YORK CITY

Active solar energy uses in residential and business settings within
New York City were investigated to determine the various ways solar

energy is collected, stored and used. The goals of the inventory were to
locate as many collectors as possible, to determine how many collectors

actually were in use, to determine the number of businesses and
residences that had working solar systems, and to compute the amount of
money solar collector owners saved by investing in solar energy.
Persons connected to the solar field were solicited to obtain names
of persons and businesses that use solar collectors. These sources
revealed other locations of solar collectors and led to more information

concerning other solar experts and businesses. In addition to the help the
above-mentioned experts provided, old newspaper clippings, federal/
state and city government information sources, area academic
institutions, and regional solar manufacturers were canvassed. Finally, a
city-wide press release was issued that requested the public to report
the locations of any solar collectors to the Department of City Planning.
The Department of City Planning, with the assistance of graduate
students and solar experts, developed a questionnaire. This questionnaire
was used to organize information obtained by telephone interviews with
solar collector owners.
The next step was to contact the solar collector owners. The
Department of City Planning mailed ninety-eight (98) informational

packets to known solar owners which contained a letter describing the
study and a multi-questioned, pre-stamped, and addressed response card.
Owners were asked about the working condition of the solar system and
requested to rate their system on the response card. Respondents were
also asked to indicate whether they would like to have an interview to
discuss their solar energy system.
The Department of City Planning encountered many problems in
locating solar collectors. Solar manufacturers and small solar retailers
within New York were either reluctant to provide addresses, were out of
business, or were unavailable for comment. Only two firms were willing
to retrieve files of past solar installations. Federal, state and city
governments were very cooperative but did not have much substantive
information related to the actual location of solar facilities.
This search into the location of active solar collectors revealed a
number of findings. (Passive solar facilities were not sought.) In 1979,
the cost of installing a solar system for the average house ranged from
$3000 to $6000 after federal, state and city solar energy income tax
credits. The income tax credits are no longer available; a solar system
had to be operational by January 1, 1986, to qualify for federal and state
income tax credits, but the New York State Real Property Tax Law,
enacted in 1977 and amended in 1979, provides a fifteen (15) year real
estate tax exemption for eligible solar and wind energy systems
constructed prior to July I, 1988.
The total number of respondents with current working solar systems
were forty (40) out of the forty-two (42) reported solar systems. In
addition, the inventory provided evidence that some individual owners
have had their solar collectors shaded from direct sunlight by buildings

and tall trees. They expressed an interest in whether New York City plans

to help preserve their solar access.

Inventory results

Summary:

Mailed letters.........98 Working solar units....40

Returned letters to Non-working units...... 2
the agency ...........42
Average age of the
Persons interested in solar collector ....4.63
further interview.... 38
Residential use ...... 41
Actual completed
interviews ...........20 Business use ........... 1

Performance rating of
solar installations:

Excellent ......... 0-20
Good .............. .. 16
Fair ................. 0
Poor................. 5

Location of solar collection systems

Brooklyn:

33 Prospect Pi., 11217 128 State St., 11201
201 6th Ave., 11217 267 6th Ave., 11215
554 1st St., 11215 313 12th St., 1'1215
2171 Cropsey Ave.,11214 150 55th St.
1922-1 Troutman St. 638 Bushwick Ave., 11221
227-6500 16th Ave.,11204 29 Fort Green, 1.1217
14 Pierrepont St., 11201 18 College Pi., 11201
577 6th St., 11215 1410 Bedford Ave., 11216
340 Marine Ave., 11209 2370 E. 29th St., 11229
108 1/2 Douglas St.,11231 1433 E. 57th St.
370-372 Hooper St., 11211

Staten Island:

49 Mohn PI., 10301 62 Jacques Ave., 10306
2400 Manhattan Bldg. 129 Fairfield St., 10308

Queens:

42 E. 221 1st St., 10013 216-32 Rockaway Point Blvd.,
25 E. 221 1st St., 11697 11209
38 E. 221 1st St., 10013 36 E. 221st St., 10013
151-14 Bayside Ave., 11354 29-04 203rd St., 11360
117 E. 222nd St., 11697 217-62 Corbett Rd., 11361
159-39 89th St., 11414 2 E. 220th St., 11697
1807 Hecksher Blvd., 11706 107 E. 222nd St., 11697
126-30 144th St. 118-29 Queens Blvd., 11377
121-17 198th St., 11413 111-32 167th St.
80-30 164th St. 27-32 Humphrey St.
159-39 89th St. 8613 90th St.
29-11 Queens Plaza, 11101

Manhattan:

53 W. 94th St., 10025 313 W. 89th St., 10024
320 w. 11th St., 10014 16 W. 9th St., 10011
924 W.E.A., 10025 43 W. 48th St., 10036
110 W. 81st St., 10024 331 W. 71st St., 10023

28 Hubert St., 10014 333 W. 88th St., 10024
225 E. 30th St., 10015 129 E. 61st St., 10021
274 W. 11th St., 10011 439 W. 22nd St., 10111
381 Park Ave. So.,10010 90 Beekman St.
421 Hudson St., 10014 90 St. at E. River, 10028
777 10th Ave. 59,61 W. 88th St.
62,64 W. 89th St. 56 W. 89th St., 10024
484 W. 12th St., 11215 331 W. 71st St., 10023
114 Washington Pi., 10014 320 W. 15th St., 10011
43 W. 94th St., 10025 25 W. 88th St., 10024
423 W. 22nd St., 110011 52 W. 76th St., 10023
315 W. 92nd St., 10025 44 W. 94th St., 10025
42 W. 12th St., 10011 72 Bank St., 10014
143 W. 95th St., 10025 32 W. 89th St.
19 W. 44th St. 519 E. [lth St.
33 E. 11th St. 353 W. 57th St.
523 E. 5th St. 948 Columbus Ave.
319 W. 89th St. 72 Bank St., 10014
50 W. 11th St., 10011

APPENDIX 2
CONSTRUCTION OF SOLAR ENVELOPE (See Section 2.)

Construction of a solar envelope for a land parcel involves
creating axonometric drawings. Axonometric drawings provide a point of
reference similar to aerial photographs at an oblique angle. An
axonometric diagram shows vertical and horizontal dimensions as they
exist, to scale, in reality. To create an axonometric drawing, a drafting
triangle is used to draw angles and lines. To draw the axonometric
diagram for a solar envelope, the altitude and azimuth angles for New
York City (provided in Table 11) must be used. The following procedure
for drawing the axonometric diagram for a solar envelope first details
the step-by-step method for a "modified solar envelope" and then shows
the longer, more complicated method for constructing solar envelopes at
the Annadale-Huguenot site:

Step 1 -- Locate the corners of the land parcel and mark them.
Then mark the middle of the land parcel and place other marks

equidistant from the middle mark to all the corners and place marks
equidistant from each corner to each corner (See Fig. 17.).

Step 2 -- After completing Step 1, go back to each mark
previously made and using Table 11, draw the azimuth angle from the
mark outwards until the line strikes an adjacent property (neighboring
property lines at ground level). Do not include streets, sidewalks and
greenspaces as adjacent property.

Step 3 -- Duplicate this process eight more times on separate
sheets of transparent paper using all the different azimuth angles
provided in Table 11.
Step 4 -- Where the lines in Step 2 reach the first adjacent
property determine the length of that line. Then multiply the distance by
the tangent of the altitude angle supplied in Table 11. This will
determine --for specific hours-- the maximum height of any building or
tree at that particular point at the marks that were mnade in Step 1.
Thus, a "solar pole" has been constructed on top of each mark that was
made on the original land parcel. Duplicate this process eight more times
for all the times provided in Table 1 1.
Step 5 -- Draw a line from the top of the solar pole to where the
line in Step 1 hits the adjacent property. A cross-section of a solar
plane has been constructed.
Step 6 -- Place all the transparencies of the solar planes on top of
each other. At every location where the solar planes bisect, place a dot
on the paper. After all the bisecting lines have been dotted, draw lines
from the dots outwards to the corners of the property or to the nearest
boundary, whichever is closest to the dot. A solar envelops, or
specifically a "modified solar envelope" is constructed.

This procedure is illustrated as the modified solar envelopes
prepared for the East River Landing site in Figure 18.
The longer procedure is next illustrated f or the
Annadale-Huguenot site, including the division of a solar envelope into
smaller envelopes, in Figure 19.

f.od of l cme rCr . ',r F, CUS arg

Step 1 Step 2
Marking where Azimuth angles as
solar poles are lines drawn on the
site

X,,, I~,- -

Step 3 Step 4 Step 5
Measuring each Measuring each Drawing line from
azimuth line azimuth line & top of solar pole to
calculating the where azimuth line
height of solar hits adjacent
pole property

Fig. 17. CONSTRUCTION OF SOLAR ENVELOPE.

Table 11. AZIMUTH AND ALTITUDE OF THE SUN.
Time of day

Date 9:00 AM and 10:00 AM and 12:00
3:00 PM 2:00 PM Noon

December 21

Azimuth 138.1 150.6 180

Altitude 14.0 20.7 26.5

Tangent of 0.249 0.378 0.498
altitude angle

March 21 & Sept. 21

Azimuth 122.7 138.1 180

Altitude 32.8 41.6 50

Tangent of 0.644 0.887 1.19
altitude angle

June 21

Azimuth 99.8 114.2 180

Altitude 48.8 59.8 73.5

Tangent of 1.142 1.718 3.376
altitude angle

March 21 & September 21
10:00 AM

/<-~~
Fig. 18. MODIFIED SOLAR ENVELOPES, EAST RIVER LANDING.
1 00

I.'

jjr

March 21 & September 21

12:00 noon

Fig. 18, Continued.

101

ttI

A ~ ~ ~~~~~~~A

March 21 & September 21
2:00 PM

1 02

March 21 & September 21
8:00 AM
(Note: Used 9:00 AM for
final solar envelopes.)

Fig. 18, Continued.
103

Note I:Since this part of
the site has a maximum
width of 300 ft.,a maxi-
mum solar envelope can
be constructed; in this
t ,case it measures 300 ft.
by 200 ft.

Note 2:The maximum en-
1460 V. -a X|\velope can be divided as
eight smaller envelopes
\, -to obtain basic lot size
\,, \o of 75 ft. x 100 ft.

20 ft.

Note 3: Where envelope's east
end is shown as a vertical "wall"
some afternoon shading of the
adjacent street is allowable. %/

Note 4: Where envelope's west
end is shown as a vertical "wall"
an option is available for limited
shading of the adjacent open space/
wetlands area.

maximum width of site is 300 ft.

Fig. 19. SOLAR ENVELOPES, ANNADALE-HUGUENOT, INCLUDING
DIVIDING LARGER SOLAR ENVELOPE INTO SMALLER ENVELOPES.

104

The solar envelope for the east part of the Annadale-Huguenot site was
constructed in accordance with procedure developed by Ralph Knowles (See
bibliography.) but adapted by the study team for use in New York City, as
follows:

Step 6 (See Steps 1-5.)
Positioning morning and
afternoon triangles (each
triangle formed in Step 5 Summer, 9:00 AM
by the hypoteneuse of the
solar pole & azimuth line)

NORTH

W E

/ ~ �~ / . ,

/~~ :
s~~~~~~~~~~~~~~~~~~~~~~~

Fig. 19. Summer, 3:00 PM
105

Step 6, Continued

/ \,

Winter, 9:00 AM Winter, 3:00 PM

Step 7
Intersecting afternoon and .
morning triangles to find;
redundancies (parts of the / '
triangles which shade each
other) --

Summer morning intersects afternoon

Fig. 19, Continued.

106

Step 7, Continued

Winter morning intersects afternoon

Step 8
Eliminating redundant parts
of triangles after their
intersection,

Fig. 19. Winter

1 07

Step 9
Establishing the hip lines
and expressing each hip
as a triangle

Summer

Winter

Fig. 19, Continued.

108

Step 10
Intersecting the summer
hip triangle with winter
morning triangles from
Step 6

tAX'\\~~

Fig. 19, Continued.
109

Step II
Intersecting the winter
hip triangle with the summer
afternoon triangles from
Step 6

Step 12
Finding the ridgeline of
the resultant solar envelope

,it

Fig. 19, Continued.
110

The construction process has yielded a maximum solar envelope for the
width of the site (300 ft.). When this solar envelope is subdivided,following
a standard mathematical procedure of similar triangles, a basic lot of 75
ft. by 100 ft. is obtained. (The maximum solar envelope, or a "nesting" of
eight of these basic lots, measures 300 ft. by 200 ft.) Once the envelope is
determined, individual houses or rowhouses can be constructed within the
volume subscribed by the envelope, as follows:

NORTH

W E
20 ft.

Note: If the building
constructed within the
envelope exceeds the
surfaces of the envelope,Il
then the building will
shade adjacent lots.

Fig. 19, Continued.
111~~~~..~.!