Abstract:
Sri Lanka has a warm humid climatic condition in low altitudes since it is located
close to the equator. In many commercial buildings located in low altitudes, airconditioning
is used as a popular option for providing the thermal comfort. However,
this option is causing a lot of problems in recent past due to the energy crisis faced by
Sri Lanka. The continuous increase of consumers has shifted the energy generation
from hydropower to fossil fuels. Due to the recent price hikes of the petroleum in the
world market, the electricity tariff rates have also been increased substantially.
Therefore the cost of air-conditioning has increased considerably. With this,
there is a considerable interest to optimize the performance of the air-conditioning
systems. So that energy usage could be minimized.
The reduction of energy used for air-conditioning is not a straightforward task. This
is because it is important to maintain the thermal comfort indoors at an acceptable
level. Therefore, developing strategies to reduce the energy consumed for airconditioning
is important which has to be achieved without compromising thermal
comfort of the occupants. The feasibility of the adjusting starts stop sequence of the
air-conditioning plants was investigated with the aid of computer simulations carried
out for a ten-story building. The effect on thermal comfort was determined by using
the Predicted Mean Vote (PMV) index. It was shown that the number of operating
hours could be reduced without affecting the thermal comfort, especially towards the
end of the office hours. Such saving could be extremely important for countries like
Sri Lanka that is facing an energy crisis amid the need to increase the number of
consumers.
The significance of such energy savings is quantified in terms of the number of rural
houses that could be provided electricity. It is shown that the energy saved by
adjusting the start stop sequence of a ten-story building is sufficient meet the
electricity demand in about fifty rural houses.
