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					          Prepared by
                                                        CONSTRUCT CANADA DESIGN CHARRETTE
     Enermodal Engineering

                                         SOLAR DESIGN GUIDE
                                                               TORONTO ONTARIO
The Solar Resource           2
                                          • Latitude 43.5°N    Longitude 80°W           Elevation 173 m
Window Design                4
                                          • Electricity Cost $0.06/kWh   $6.15/kW   Gas Cost $0.22/m3
Shading Strategies           7
                                                                                City                      Suburbs
Daylighting                  8
                                  Heating Degree Days                           3650                       4050
Solar Thermal Applications   10   (base 18°C)
                                  Heating Design Temperature                    -18°C                      -20°C
Solar Electricity            11
                                  Cooling Design Temperature       31°C (DB)/23°C(WB)               31°C (DB)/24°C(WB)
Additional Resources         12

                                                     SPONSORED BY NATURAL RESOURCES CANADA
                                                                                                           CONSTRUCT CANADA DESIGN CHARRETTE                                             2

                                                                                                            The Solar Resource:
                                                                                                              Solar Radiation
                                                                                                                  Monthly Solar Radiation (Toronto)

                                                      Incident Solar Radiation (kWh/m²/day)
Solar radiation charts show the
monthly distribution of solar ra-                                                                                                                                   South
diation on five surfaces: vertical                                                            4

surfaces facing north, south and
east/west; horizontal surfaces;
and south-facing surfaces tilted                                                                    South
at 45°. Solar heat gain to a build-                                                                 (vertical)

ing is determined by multiplying                                                              2                   East/West
solar radiation values by the solar
heat gain coefficient for windows                                                             1
(see page 5).                                                                                                                                      North
Use the radiation values for verti-
                                                                                              Jan    Feb     Mar      Apr      May   Jun   Jul   Aug     Sep    Oct    Nov   Dec
cal surfaces to determine solar
gains through windows. Use the
values for a horizontal surface to
determine solar gains through flat                                                                               Seasonal Solar Availability (Toronto)
skylights. Use the values for a                                                                                               kWh/m2
45° tilted, south-facing surface to                                                                                   North          East/West            South         Horizontal   South 45°
design solar DHW systems and
PV systems.                           Winter (October to April)                                                        167                 358              591              492        695

                                      Summer (May to September)                                                        233                 480              414              797        769

                                      Annual                                                                           400                 838             1005              1289      1464
                                    CONSTRUCT CANADA DESIGN CHARRETTE          3

                                     The Solar Resource:
                                       Sun Path Charts

                                           Sun Path Chart, 43° North
                                     Hourly Fraction of Daily Total Sunshine

Sun path charts show the posi-
tion of the sun by month and by
hour of the day. The numbers
within each section of the chart
indicate the fraction of monthly
solar radiation for a particular
hour (assuming that the sky is

To assess the impact of shading
caused by nearby structures,
sketch the southern skyline from
east to west on a sunchart. Add
the monthly values covered by
the shaded portions to determine
the amount of solar radiation not
received due to shading.
                                                               CONSTRUCT CANADA DESIGN CHARRETTE                      4

                                                                     Window Design:
                                                                       Heat Loss
Window heat loss is directly pro-
portional to U-value. Low U-
values reduce peak heating load
and can eliminate the need for                                        Commercial Window U-values
perimeter heating. Conventional
windows have high U-values be-                       Glazing Type                      Frame Type        U-value (W/m2K)
cause of poor glazing, metal
edge-spacers and narrow ther-                                       Conventional Commercial Windows
mal breaks.
                                     Single                                     TB Metal                       6.1
High performance windows have        Double                                     TB Metal                       3.2
at least one low-e coating, an ar-
gon gas fill and an insulating       Double                                     Curtainwall (4 mm TB)          3.5
edge-spacer. High-performance
frames are non-metal (for exam-      Double, low-e                              Curtainwall (4 mm TB)          2.9
ple, fibreglass) or have a mini-                                 High-performance Commercial Windows
mum 12 mm thermal break. The
cost premium for high perform-       Double, low-e, argon, insulating spacer    TB Metal                       2.3
ance windows is approximately
$50/m2 for double-glazed win-        Double, low-e, argon, insulating spacer    Curtainwall (12 mm TB)         2.4
dows and $120/m2 for triple-         Double, low-e, argon, insulating spacer    Insulated fibreglass           1.7
glazed windows.
                                     Triple, low-e, argon, insulating spacer    TB Metal                       1.5
Vision and spandrel panels can
have poor energy performance         Triple, low-e, argon, insulating spacer    Curtainwall (12 mm TB)         1.7
due to minimal thermal breaks.       Triple, low-e, argon, insulating spacer    Insulated fibreglass           1.1
Because of thermal bridging, the
metal pans in spandrel panels
should be thermally isolated from
the building.
                                                               CONSTRUCT CANADA DESIGN CHARRETTE                         5

                                                                Window Design:
                                                         Solar and Light Transmission

                                                         Glazing Light Transmission/Solar Heat Gain Coefficient
In the table of window properties
                                                                              (in percent)
to the right, the first number for
each glazing is the glazing visible   Glazing                    Clear      Blue/Green    Spectrally      Grey     Reflective
light transmission. The second                                                            Selective
number is the glazing heat gain
coefficient (SHGC). To determine      Single                    89 / 91       75 / 62       71 / 51      43 / 56    20 / 29
total window values, multiply the
numbers in the table by 0.8.
                                      Double                    78 / 70       67 / 50       59 / 39      40 / 44    18 / 21
Windows with high visible light
transmission maximize the use of      Double,                   73 / 65       62 / 45       55 / 34      37 / 39    17 / 20
daylighting. Windows with low          hard low-e
SHGC reduce cooling loads.
                                      Double,                   70 / 37       59 / 29       53 / 27      35 / 24    16 / 15
Spectrally-selective glazings are      soft low-e, e<0.05
specially designed for high visible
                                      Triple                    70 / 61       59 / 42       53 / 34      34 / 40    17 / 19
light transmission and low solar
heat gain coefficient.
                                      Triple,                   64 / 56       55 / 38       52 / 31      32 / 36    15 / 17
Blue/green or spectrally-selective     hard coat low-e
glazings are preferred to grey
and reflective glazings for day-      Triple,                   55 / 31       52 / 29       50 / 27      30 / 26    14 / 13
lighting design.                       soft low-e, e<0.05
                                                                 CONSTRUCT CANADA DESIGN CHARRETTE                                    6

                                                                    Window Design:
                                                                  Area and Orientation

                                     Window Area = 2.5 X Daylight Factor X Area of Interior Surfaces X (1-Reflectance)
Window area should be large                          Glazing Transmittance X Visible Angle of Sky
enough to provide natural light,
but not so large as to cause glare
and high heating or cooling          Daylight Factor is 1% for low light levels, 2% for typical office lighting, and 4% for bright spaces.
loads. Optimum window area
can be calculated with the equa-     Area of Interior Surfaces is the sum of the area of
tion shown to the right. The rec-    walls, floor and ceilings of a room.
ommended window-to-wall ratio
is usually between 20% and           Reflectance is the solar reflectance of interior sur-
40%.                                 faces. Use 0.7 for light-coloured rooms, 0.5 for
                                     typical offices, and 0.3 for dark-coloured rooms.
Maximize winter solar gains and
minimize summertime heat gains
by placing windows on south-         Visible Angle of Sky is 90° minus angle reduction
facing walls and by avoiding         from overhangs and nearby buildings.
west-facing windows. Place win-
dows on northern walls to provide
daylight without glare.
                                                    CONSTRUCT CANADA DESIGN CHARRETTE                               7

                                                      Shading Strategies

                                                                  Use vertical
                                                                  louvers or      Window Orientation       Shading Strategy
                                        Standard                  fins on east
                                       horizontal                 and west
Sunlight shining through windows       overhang.                                  North                   Usually not needed
can result in high cooling loads
and in undesirable glare. Exterior                                                South                   Overhang,
shading devices are far more ef-                                                                          horizontal louvers,
fective than interior shades at                                                                           trellis over window
controlling solar gains. Over-                                                    East/West               Vertical louvers,
hangs and awnings are best              Drop the                  A sloped
                                        edge for                  overhang                                horizontal slats,
used on south facades. Vertical             less                  has less pro-                           deciduous trees
louvers provide some protection       projection.                 jection.
for east and west facades. De-
ciduous trees planted for sum-
mertime shading should be lo-                                                      Window Treatment         % Reflected
cated to the east and west of a                                                                            Solar Radiation
building, and not due south of a
building.                             A louvred                  A louvred        Light interior blind,          35%
                                       dropped                   overhang
                                                                 provides dif-
                                      edge lets
Interior shades and blinds should       in more                  fuse light.      Light interior blind,          60%
only be used to control glare. Ef-         light.
fective interior treatments include
venetian blinds with their slats                                                  Dark interior blind,           20%
installed upside-down, and                                                        closed
shades installed to pull up from       Break up                   Break up an
                                                                                  Light drapes or                40%
the windowsill.                         an over-                  overhang for
                                        hang for                  less            pleated blinds, open
                                       less pro-                  projection.
                                         jection.                                 Exterior louver                85%
                                       CONSTRUCT CANADA DESIGN CHARRETTE   8


Recommended building plans are
long in the north-south exposure
and have a shallow office plan.
Office depth should not exceed
1.5 to 2.5 times height the of win-
dow head.

Light shelves and clerestory win-
dows (facing north and south)
permit light to reach building inte-
riors. Horizontal skylights are not

Locate windows high on wall-
sabove desk height. Windows
should be wide instead of tall, to
a maximum height of one metre.
Consider separate windows for
exterior views and daylighting:
clear glazing positioned high on
the wall for maximum daylight
and tinted windows positioned
low for view and glare control .
                                                  CONSTRUCT CANADA DESIGN CHARRETTE           9


Daylighting is only effective in
combination with lighting con-
trols. Electric lights should dim or
shut off when sufficient daylight is

Systems that dim lights are rec-
ommended where fine control of
light variations is required, such
as in offices. Systems that switch
lights on and off are less expen-
sive and are recommended
where lighting variations can be
tolerated, such as in common ar-
eas. Electricity savings can be                Electricity Savings Due to Lighting Controls
further increased when occu-
                                       Control Strategy           % Lighting Energy Savings
pancy sensors control lights.
Daylighting sensors should not         Stepped On/Off                            20%
be located in direct sunlight or
directly underneath artificial         Continuous Dimming                        30%
lights.                                Occupancy Sensor                          30%

                                       Stepped and Occupancy                     50%
                                       Dimming and Occupancy                     60%
                                            CONSTRUCT CANADA DESIGN CHARRETTE           10

                                        Solar Thermal Applications

Solar energy can provide up to
60% of domestic hot water
needs. Solar collectors should be           Solar DHW Required Collector Area in m2
installed at a 45° angle facing be-
tween southeast and southwest.
A storage tank of 50 L/m2 of col-     Collector Area = Litres of Daily Hot Water Load
lector is required to store heat                                    50
gained during sunny periods.           Collector Area = 4 X Number of Apartments
The storage tank is usually in-
stalled in a mechanical room as a      Collector Area = Number of Office Workers
preheat to the conventional water                                  5
heater. Solar DHW systems typi-
cally cost $500/m2 installed.

Solarwall is the trade name for a
perforated metal collector in-               Solarwall Required Collector Area in m2
stalled on the south-facing wall of
a building. The collector elimi-
nates the need for conventional       Collector Area = Outdoor Ventilation Air (L/s)
building cladding. The sun heats                                 30
ventilation air as it passes
through the collector; this air is           Collector Area = Floor Area (m2)
then delivered to the building. So-                                  40
larwall systems usually cost
$250/m2, which is less than the
cost of conventional cladding.
                                                  CONSTRUCT CANADA DESIGN CHARRETTE                     11

                                                        Solar Electricity

Photovoltaic (PV) systems con-                            PV System Performance
vert sunlight into DC electricity.
An inverter is required to convert
solar electricity to AC power. In        Peak Electricity Supply (kW) = PV Cell Area (in m2) X 0.12
most cases, electricity produced
in excess of building require-         Annual Electricity Supplied (kWh) = PV Cell Area (in m2) X 200
ments is sent to the electrical grid
and the building receives a credit
for the electricity supplied. PV
systems cost about $1500/m2
and produce power at about
$0.35 cents/kWh.

Building-integrated PV modules
are integrated into building ele-
ments such as awnings, roof
shingles and spandrel panel glaz-
ing. Semi-transparent PV panels
can be used as atria glazing to
reduce solar gains and provide

Photovoltaics are best applied
when electricity demand is re-
duced through energy efficiency
                                            CONSTRUCT CANADA DESIGN CHARRETTE                               12

                                             Additional Resources

                              Sixty energy and resource efficient technologies for commercial buildings.

                               Information and links on green building design.

                                 Information on the federal commercial building incentive program.

                               Technologies used in energy-efficient windows.

                                 Downloadable design guide, “Tips for Daylighting with Windows.”

                                  Downloadable RETScreen software for feasibility assessment of photovoltaics,
                                  passive solar, solar DHW and solar ventilation air heating.

                              Order form for design guide, “Tap the Sun, Passive Solar Techniques and
                              Home Designs.”

    Prepared by
Enermodal Engineering                   SPONSORED BY NATURAL RESOURCES CANADA

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