1. Energy use in Buildings
Week 3

2. Where are we?

3. Understanding Energy
“The ability to do work”
Energy
Measured in Joules (J)
Power
Measured in Watts (W)
= 1 J/sec
>>kWh

4. Understanding Energy
Example: kWh/day/person
108.42
239.00
194.47
50.91
122.96
51.67
17.22 21.14
0
50
100
150
200
250
300
kWh/day/person
Energy use (kWh/day/person)

5. Understanding Energy
Example: Honda Wave 120km
Vietnam average energy
consumption = 21.42kWh/pp

6. Your ecological footprint
http://myfootprint.org/

7. Energy consumption through
Buildings >> ELECTRICITY
When designing a green building, how do we
know how much electricity our buildings will
actually save?

8. Energy consumption through
Buildings >> ELECTRICITY
How do we know how much electricity our
buildings will save?
Energy Model:
- Comparison with a Baseline Model
- Comparison with a Benchmark

9. Electricity consumption
Johor Bahru Case Study, Residential House
*Kubota, Tetsu et al, "Energy Consumption and Air-Conditioning Usage in Residential
Building of Malaysia”, 2011

10. *Kubota, Tetsu et al, "Energy Consumption and Air-Conditioning Usage in Residential
Building of Malaysia”, 2011

11. Electricity consumption
Hong Kong Data, Residential
*Hoang Kong Energy End Use Data Report 2012, The Energy Efficiency office

12. Electricity consumption
Hong Kong Data, Office

13. Electricity consumption
Hong Kong Data, All buildings + Transport
*Hoang Kong Energy End Use Data Report 2012, The Energy Efficiency office

14. Electricity consumption
Hong Kong Data, Renewable Energy
*Hoang Kong Energy End Use Data Report 2012, The Energy Efficiency office

15. Electricity consumption
Hong Kong Data, Renewable Energy
*Hoang Kong Energy End Use Data Report 2012, The Energy Efficiency office

16. Renewable Energy
What types of Renewable energy are available?

17. Solar – Photovoltaics, Solar Hot
Water
Transparent Photovoltaics, CSIRO Energy Centre, Newcastle Australia

18. Solar –
Photovoltaics
- Building Integrated
Photovoltaics
(BIPV)
- Big C Green Square
PV cells on carpark
shade structure &
roof
- Green One UN
House will produce
>17% of its own
electricity

19. Photovoltaic Cells Cost and other
Considerations
- Crystalline silicon solar cell prices have
fallen from $76.67/Watt in 1977 to an
estimated $0.74/Watt in 2013
(Swanson’s Law prices fall 20% for every
doubling of production capacity)
- As of 2011 the cost of PV has fallen
below Nuclear Power
- Current developments achieving
efficiency of 44%, commercially available
cells are 14-22% efficient

20. Solar – Concentrated Solar (Thermal)
Power
Spain CSIRO Energy Research Centre, Newcastle AU

21. Solar Hot Water

22. Solar Hot Water
- Can easily supply
domestic hot water
needs in houses in
Southern Vietnam
- Northern Vietnam
may need to use
higher capacity
system to
compensate for
days without much
sun * 2011 Edition Handbook for Green Housing

23. Wind Power
Large scale wind farming High Altitude Wind

24. Wind Turbines integrated in
buildings?
147m tall Strata Building, London
Offsets 8% of power in building (equivalent to mechanical and electrical services)

25. Wind Turbines integrated in
buildings?
240m tall Bahrain World Trade Centre
11-15% of power generated by wind turbines

26. Wind Turbines integrated in
buildings?
309m tall Pearl River Tower, Guangzhou, China (SOM 2011)
Combined with PV the renewable energy generated is <10% of building energy needs
Wind turbines are a powerful green symboll

27. Hydropower?

28. Tidal or wave power?

29. Biomass? Biofuel? Geothermal?

30. Cogeneration
Heat Recovery

31. Air Conditioning
- Coefficient of Performance (COP)
* LOTUS NR V1.1

32. Air Conditioning
- Window and through wall system

33. Air Conditioning
- Split System

34. Air Conditioning
- VRF (Variable Refrigerant Flow)

35. Air Conditioning
- Chilled Beam (passive/active) & Chilled Slab
- >>Not good for tropical or humid climates

36. Lighting

38. BUT…it doesn’t matter how efficient
you are
It also comes down to the
occupants, maintenance, controllability, automata
bility and the design of the space
What are some factors that could be more
important than the efficiency of systems and
equipment?

39. BUT…it doesn’t matter how efficient
you are
Consider (AC):
- Floor area
- Air Leakage
- Individual thermal controls
- Zoning
- Set points (thermostat)
- Cleaning of filters
- Maintenance
- Building Automated System
- Thermal comfort

40. BUT…it doesn’t matter how efficient
you are
Consider (Lighting):
- Size of space
- Daylighting
- Lighting level
- Task lighting
- User controllability
- Timer lighting
- Sensor lighting
- Automated lighting
- Switch zones
- Hours of operation