Synthesis

The use of computer design tools means that an overall optimization of the building energy design can happen at the drawing table. Extra costs for some building elements can be offset by reduced costs for other elements, such as reduced investment costs for the cooling system caused by a more efficient design building envelope, that reduces the maximum cooling load. Furthermore, using life cycle calculations, extra costs for energy saving features can be offset by savings in energy costs over the life cycle of the building.

The LEO Building has been optimized using the Energy-10 computer software from National Renewable Energy Laboratory, Denver US. Among the many computer design tools available, Energy-10 was chosen, as it is very user-friendly, yet sophisticated, calculating the energy balance of the building hour by hour throughout a year.


The diagram shows the effect of applying the main energy saving features, one by one. It is seen, that reduction of the internal heat gains from lighting and office equipment is of major importance. It is noted, that the increase of the room temperature by one degree only reduces energy consumption by 10% . Therefore it is also very costly to have too low room temperatures in the 20 - 22C region.

The extra costs for the energy efficiency features of the LEO building have been RM 5.0 million, or 10% of the total building costs. With an electricity price presently at 28 cent per kWh, the extra costs will be paid back within the first 10 years of the building lifespan. Energy efficiency is very cost-effective, it should be applied throughout the building sector, and the implementation of Malaysian Standard 1525:2001 for non-domestic buildings is seen to be well justified.