Effect of Building Shape And Neighborhood Design On Solar
Potential And Energy Performance
NSERC Smart Net-Zero Energy Building Strategic Research Network
Réseau De Recherche Stratégique Du sur les bâtiments a consommation
énergétique net zéro
Caroline Hachem, PhD, B. Arch, MSc. Arch., MSc. Eng.
Postdoctoral fellow, NSERC Smart Net-zero Energy Buildings Strategic
Research Network Concordia University
Vancouver
Edmonton Calgary
Toronto
Halifax Montreal
Ottawa
Lat 53 N Degree-days 5212
PPVV ppootteennttiiaall ooff CCaannaaddaa aanndd SSNNEEBBRRNN 29 researchers from 15 Universities, NRCan, Hydro Quebec, Gaz-Metro, building industry leaders
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� Building design plays a key role in influencing energy consumption of neighbourhoods.
� Some design parameters can significantly affect the solar potential and energy performance of houses and neighborhood ►► They should be implemented since the ddeessiiggnn ssttaaggee.
This presentation assumes that we have the possibility to design a whole solar neighborhood, or a cluster of buildings in a neighborhood.
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Path Towards Net Zero Energy Neighborhood
DDeennssiittyy
Energy efficiency measures
BBuuiillddiinngg sshhaappee
Solar Potential
SSiittee llaayyoouutt
Integration of PV or PV/T
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A holistic systematic design approach for
solar neighborhoods is required
PPrrooggrraamm
11.. HHoouussiinngg ddeessiiggnn Building envelope Geometrical parameters Roof design-ready for the iinntteeggrraattiioonn ooff ssoollaarr ccoolllleeccttoorrss
22.. NNeeiigghhbboouurrhhoooodd ddeessiiggnn Road layout Density: Row and spacing effects
3.. TToowwaarrddss MMiixxeedd UUssee NNeeiigghhbboouurrhhooooddss
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Trade-off between using higher insulation and larger south facing window area. Optimal value of insulation is selected to balance between the increase in cost and
energy saving.
45% reduction
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Insulation and South Window Effect
DDwweelllliinngg SShhaappeess
Effect of window properties
Reduction of 40% Reduction of 50%
Hea
ting
load
(kW
)
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Insulation and South Window Effect
DDwweelllliinngg SShhaappeess
0°-30° - increase of heating load by 8% 30°-60° - increase of heating load by 30%
Increase of heating load
by 30%
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Orientation DDwweelllliinngg SShhaappeess
L
The aspect ratio should be selected to compromise between heating and cooling loads
Expected to be higher with larger windows on West and East
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13
DDwweelllliinngg SShhaappeess Aspect Ratio
S
30° 30°
30°
30°
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Orientation Solar neighbourhood design
Important to design the larger facade of the building with a near
south orientation
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� Deviation from rectangular shape leads to increase in heating load, however Ø Proper design of facades and windows can reduce the energy use Ø Non rectangular shapes may counterbalance the increase of heating load
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DDwweelllliinngg SShhaappeess Geometry
Heating consumption is
reduced dramatically for
shapes like U and H when the south
window constitutes 50% of the façade.
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� Deviation from rectangular shape leads to increase in heating load, however Ø Proper design of facades and windows can reduce the energy use Ø Non rectangular shapes may counterbalance the increase of heating load
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DDwweelllliinngg SShhaappeess Geometry
DR=1/2 DR=3/2 DR=1
0
500
1000
1500
2000
2500
3000
3500
Rectangle L (DR=1/2) L (DR=1) L (DR=3/2)
heat
ing
Loa
d 8% 19%
25%
Depth Ratio (DR)
Number of shading facades Reducing the energy use
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DDwweelllliinngg SShhaappeess Geometry
� BBuuiillddiinngg sshhaappeess lliikkee iinn sshhaappeess,, HH aanndd TT sshhaappeess hhaavvee llaarrggeerr ssoouutthh ffaacciinngg rrooooff aarree ffoorr tthhee ssaammee fflloooorr aarreeaa aanndd tthheerreeffoorree hhaavvee tthhee ppootteennttiiaall ttoo iinntteeggrraattee llaarrggeerr PPVV ssyysstteemm..
Living area
BBeenneeffiittss ooff nnoonn rreeccttaanngguullaarr sshhaappeess
Living area
Living area
Living area
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DDwweelllliinngg SShhaappeess Geometry
� LLiivviinngg aarreeaass iinn sshhaappeess lliikkee LL ,, UU aanndd TT sshhaappeess hhaavvee lleessss ddeepptthh →→ppeenneettrraattiioonn ooff ssoollaarr rraaddiiaattiioonn wwhhiicchh iiss bbeenneeffiicciiaall ffoorr ddaayylliigghhtt aanndd ppaassssiivvee hheeaatt
Living area
BBeenneeffiittss ooff nnoonn rreeccttaanngguullaarr sshhaappeess
Living area
Living area
Living area
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DDwweelllliinngg SShhaappeess Geometry
Reduction of wasted space for circulation
and vestibules, which can save land
area
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DDwweelllliinngg SShhaappeess Geometry
(a) (b)
20% more roof area
Different tilt angle Optimal radiation
for summer and winter
� OOppttiimmaall ttiilltt aannggllee aapppprrooxxiimmaatteess tthhee llaattiittuuddee ooff tthhee llooccaattiioonn � OOppttiimmaall oorriieennttaattiioonn iiss nneeaarr ssoouutthh
TTiilltt AAnnggllee
PPhhoottoovvoollttaaiicc IInntteeggrraattiioonn
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Solar community concepts allow for: Ø non-rectangular or rectangular house shapes and designs, Ø appropriate BIPV roof designs, Ø optimal design passive solar gains. These designs affect significantly the peak demand and the peak
generation of electricity.
(c)
(a)
U2
U1
U5 U4
U3 U2
U1
U5 U4
U3 U2
U1 U5 U4
U3
U2
U1 U5
U4 U3 U2
U1 U5
U4 U3 U2
U1 U5
U4 U3
(b)
U3 U2 U1 U1 U3 U2 U1 U3 U2
Solar neighbourhood design: Optimizing solar potential
Hachem C., A. Athienitis, P. Fazio, (2011), Investigation of Solar Potential of Housing Units in Different Neighborhood Designs, Journal of Energy and Buildings, Volume 43, Issue 9, Pages 2262-2273.
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Road layout
Difference of heating load ≤3%
S S
Solar access principles are not applied: openings are toward the street (north facing)
Increase of heating load by 60%
Increase of heating load by 7%
Increase of heating load by 60%
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� The average heating load is not significantly affected by the layout of streets provided solar access is respected.
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Solar neighbourhood design
Example of trade -off between different building shapes, land area and energy efficiency
S 45°
POA r
(a) (c) (b)
Road layout
660
680
700
720
740
760
780
800
820
0
500
1000
1500
2000
2500
3000
3500
R R(O-45) V-SW45
Loa
d (k
Wh)
Average Heating
Average Cooling
Total Area of land
S
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Solar neighbourhood design
Density- Effect of Spacing
0
100
200
300
400
500
600
700
A D 2D
Cooling consumption (kWh)
Heating consumption (kWh)
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� up to 35% reduction of heating load can be achieved in attached units
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Solar neighbourhood design
Living area Living area
Height
≈2 times Height
The distance between rows is dependent on the height of the shading buildings (about 2 times)
(a)
(b)
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Density- Effect of Spacing
Solar neighbourhood design
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Seasonal thermal storage
BIPV Systems
BIPV Systems
District heating
Solar collectors
Generation of 62% of the total energy use
Generation of 80% of the total energy use
� Some house shapes (e.g L-shape) are more beneficial in a specific site layout.
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olar Neighbourhood Design
Shape of housing units a) General site considerations b) Minimizing total area for a given
functional area . c) Energy considerations ‒ Passive and Active solar design. General o Orientation: within the optimal
range. Otherwise, trade-offs in shape design should be made.
o South facing window area. Rectangular shapes: Aspect ratio ‒ of 1.3 to 1.6 should be applied . Self -Shading shapes (like L shape) o Number of shading facades o Ratio of shading to shaded façade
widths (depth ratio), and o Angle enclosed by the wings. Roofs (default hip roof): Key effects : surface area, tilt angle and orientation.
S
30° 30°
30°
30°
Design Guidelines
S
Rectangular shapes: Self -Shading shapes:
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Two shading wings
Living area
Living area
Height
≈2 times Height
S
30° 30°
30°
30°
Design Guidelines
Positioning of housing units on a site. a) Straight road (east west direction) Low density- Detached units o Apply passive solar design for shapes. Minimum
distance between adjacent units (bylaws) High density- Attached units o Attached units are recommended for increased density.
For non-convex shapes configurations, the depth ratio and number of shading facades should be considered.
b) Curved Road Low density- Detached units o Planar obstruction angle (POA) o Orientation around the curve High Density - Attached units o Similar observations as for straight road. Additional
design issues should be addressed. c) Row Configurations Low density ‒ Detached units o Distance between rows of 1.5 - 2 times the height of the
shading building. High density ‒ Attached units o The same design recommendations as detached units.
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EExxaammppllee ooff DDeessiiggnn
S
Garage covering the south facades
No windows on south facades, aspect ratio is small
Suggested modification
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