Effect of Building Shape And Neighborhood Design On Solar Potential And Energy Performance

Transcription

1 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 Effect of Building Shape And Neighborhood Design On Solar Potential And Energy Performance

2 2 PV potential of Canada and SNEBRN 29 researchers from 15 Universities, NRCan, Hydro Quebec, Gaz-Metro, building industry leaders Lat 53 N Degree-days 5212 Edmonton Calgary Vancouver Montreal Ottawa Toronto Halifax

3 3 3 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 design stage. This presentation assumes that we have the possibility to design a whole solar neighborhood, or a cluster of buildings in a neighborhood.

4 TOWARDS NET ZERO ENERGY COMMUNITIES

5 5 Energy efficiency measures Integration of PV or PV/T Solar A holistic systematic design approach for solar neighborhoods is required Potential Building shape Density Site layout Path Towards Net Zero Energy Neighborhood

6 6 1. Housing design Building envelope Geometrical parameters Roof design-ready for the integration of solar collectors 2. Neighbourhood design Road layout Density: Row and spacing effects 3.. Towards Mixed Use Neighbourhoods Program

7 BUILDING DESIGN

8 8 45% reduction Dwelling Shapes Insulation and South Window Effect

9 9 45% reduction 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. Dwelling Shapes Insulation and South Window Effect

10 10 10 Effect of window properties Reduction of 50% Heating load (kw) Reduction of 40% Dwelling Shapes Insulation and South Window Effect

11 11 Orientation Aspect Ratio Dwelling Shapes

12 12 Increase of heating load by 30% increase of heating load by 8% increase of heating load by 30% Dwelling Shapes Orientation

13 13 Expected to be higher with larger windows on West and East L The aspect ratio should be selected to compromise between heating and cooling loads Dwelling Shapes Aspect Ratio

14 Important to design the larger facade of the building with a near south orientation S Solar neighbourhood design Orientation

15 15 Ø Ø 15 Deviation from rectangular shape leads to increase in heating load, however Proper design of facades and windows can reduce the energy use Non rectangular shapes may counterbalance the increase of heating load Dwelling Shapes Geometry

16 16 16 Heating consumption is reduced dramatically for shapes like U and H when the south window constitutes 50% of the façade. Ø Ø Deviation from rectangular shape leads to increase in heating load, however Proper design of facades and windows can reduce the energy use Non rectangular shapes may counterbalance the increase of heating load Dwelling Shapes Geometry

17 17 Reducing the energy use 3000 heating Load Number of shading facades Depth Ratio (DR) % % % DR=1/2 Rectangle DR=1 L (DR=1/2) L (DR=1) L (DR=3/2) DR=3/2 Dwelling Shapes Geometry

18 18 Benefits of non rectangular shapes Living area Living area Living area Living area Building shapes like in shapes, H and T shapes have larger south facing roof are for the same floor area and therefore have the potential to integrate larger PV system. Dwelling Shapes Geometry 18

19 19 Benefits of non rectangular shapes Living area Living area Living area Living area Living areas in shapes like L, U and T shapes have less depth penetration of solar radiation which is beneficial for daylight and passive heat Dwelling Shapes Geometry 19

20 20 Reduction of wasted space for circulation and vestibules, which can save land area Dwelling Shapes Geometry

21 21 Different tilt angle Optimal radiation for summer and winter 20% more roof area (a) (b) Optimal tilt angle approximates the latitude of the location Optimal orientation is near south Photovoltaic Integration Tilt Angle

22 22 Reduction of 12% Photovoltaic Integration Orientation

23 NEIGHBORHOODS

24 24 Ø Ø Ø Solar community concepts allow for: non-rectangular or rectangular house shapes and designs, appropriate BIPV roof designs, optimal design passive solar gains. These designs affect significantly the peak demand and the peak generation of electricity. U1 U2 U1 U3 U2 U3 U1 U3 U2 (a) U4 U3 U4 U2 U3 U2 U4 U5 U5 U1 U4 U3 U2 U2 U1 U5 U1 U1 U5 U3 U1 U5 U4 U3 U2 (b) U1 U5 U4 U3 U2 (c) 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 Solar neighbourhood design: Optimizing solar potential

25 25 25 Solar access principles are not applied: openings are toward the street (north facing) Increase of heating load by 60% Difference of heating load 3% Increase of heating load by 7% S S Increase of heating load by 60% The average heating load is not significantly affected by the layout of streets provided solar access is respected. Solar neighbourhood design Road layout

26 26 Example of trade -off between different building shapes, land area and energy efficiency POA r S S (a) (b) (c) Load (kwh) Average Cooling Total Area of land Average Heating 680 R R(O-45) V-SW Solar neighbourhood design Road layout

27 27 27 Cooling consumption (kwh) Heating consumption (kwh) A D 2D up to 35% reduction of heating load can be achieved in attached units Solar neighbourhood design Density- Effect of Spacing

28 28 28 (a) (b) Height Living area Living area The distance between rows is dependent on the height of the shading buildings (about 2 times) Solar neighbourhood design 2 times Height Density- Effect of Spacing

29 29 29 Generation of 62% of the total energy use BIPV Systems Solar collectors Seasonal thermal storage Generation of 80% of the total energy use Some house shapes (e.g L-shape) are more beneficial in a specific site layout. BIPV Systems District heating olar Neighbourhood Design

30 30 Shape of housing units a) General site considerations b) Minimizing total area for a given functional area. 30 c) Energy considerations Passive and 30 Active solar design. General S o Orientation: within the optimal S range. Otherwise, trade-offs in shape design should be made. Rectangular shapes: Self -Shading shapes: 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. Design Guidelines

31 31 Two shading wings S Living area 2 times Height Height Living area 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 times the height of the shading building. High density Attached units o The same design recommendations as detached units. Design Guidelines

32 32 Suggested modification S No windows on south facades, aspect ratio is small Garage covering the south facades Example of Design

33 Thank You