Performance
How does your building perform compared with other similar buildings?
Benchmarks
Why do we need a benchmark?
We need to be able to measure the performance of a building. Comparing the energy consumption data with benchmarks can provide an indication on how well your building is performing. For example, energy consumption (kWh) divided by floor area (m2) giving kWh/m2 per annum provides a standard measurement. Large buildings will generally consume more energy compared with smaller buildings. By taking into account the floor area, a better comparison can be made between buildings of different sizes. Using this measurement of kWh/m2, comparisons can then be made to see how well your building is performing compared with other similar types of buildings.
Types of Buildings include:
- Residential
- Commercial (Office Building)
-
Other (Special Purpose)
- Supermarkets
- Hospital
- Schools
Energy Benchmark Example
Different supermarket layouts and different products offered means varying store equipment requirements, such as the number of cooling and freezing cases installed. Energy consumption per square meter of store space varies enormously thoughout the world as illustrated below:
| Supermarket |
Energy Usage kWh/m2 pa |
|---|---|
| Albert Heijn, Netherlands | 312 |
| ICA Kvantum, Sweden | 391 |
| Tops, Malaysia | 523 |
| California, USA | 550 |
| Plaza Vea, Peru | 639 |
| Bi-Lo, USA | 672 |
| CIBSE, Benchmark, UK | 670 |
| Giant, Landover, USA | 878 |
| Typical supermarket, Australia | 1000 |
| A supermarket in Australia (12 months old) | 1800 |
This example shows that there is clearly huge potential to reduce energy consumption in this particular supermarket in Australia. The American stores have a higher energy consumption than the European stores because their product assortment contains more refrigerated and frozen products. They also use more air conditioning systems. Stores in hot and humid regions such as Tops Supermarket in Malaysia require more air conditioning and more powerful cooling and freezing systems. However, in Australia where there is a large amount of open style refrigeration units, there is an excessive amount of energy consumption per square metre compared with other countries in the world.
A new supermarket is being built in Gisborne, 50km North-West of Melbourne in Australia. The store is due to open in Easter 2005. The design incorporates a number of energy efficiency initiatives and the performance will be measured after 12 months data is obtained. This will allow us to see if the actual performance meets the design calculations. This comparison can be used to improve further designs.
See the Coles Supermarkets Project for more information.
Build Green can find methods for you to reduce the energy consumption in your building and your energy bill.
Rating Systems
Rating systems aim to provide an indication of building performance. There are many rating systems around the world.
The New Zealand Green Building Council has two rating tools at present, with others under development:
- Homestar™ (for residential buildings) evaluates the environmental attributes of New Zealand's stand-alone homes in terms of energy, health and comfort, water, waste and more.
- Green Star (for commercial buildings) evaluates the environmental attributes and performance of New Zealand's buildings using rating tool kits applicable to each building type and function.
Here is a selection of the rating systems available in Australia:
- Green Star – Green Building Council of Australia
- FirstRate – Sustainable Energy Authority Victoria (SEAV)
- NatHERS – Nationwide House Energy Rating Scheme
- NABERS – National Australian Built Environment Rating System
- Basix – Building Sustainability Index (NSW Department of Infrastructure, Planning and Natural Resources)
Other rating systems include:
- LEED (USA) – Leadership in Energy and Environmental Design.
- LEED (Canada) – Adaptation of LEED for Canadian climates, construction practices and regulations. One main difference is the use of SI units rather than foot-pound units.
- BREEAM (UK) – Building Research Establishment Environmental Assessment Methodology.
Most of the rating systems are designed for residential and commercial office buildings. There is certainly scope for further development of rating systems for special purpose buildings such as schools, supermarkets, shopping centres and hospitals.
Also, most of the rating systems are based on design data and not actual data. The real performance of a building can only be measured with actual data.
Build Green can provide specific analysis on the characteristics of various types of buildings and recommend measures that will reduce energy consumption.
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