Study on the Effects of Heat Transfer through Glass Walls on Cooling Load

The academic buildings in Universiti Teknologi PETRONAS (UTP) are very unique in its design and are exceptional. One of the things that makes it outstanding is the use of glass as the wall material. Highly glazed buildings are intended to be airy, light and transparent with more access to daylight. However, direct access to sunlight means more heat is gained and this significantly increases the total cooling load of buildings. Thus more energy needs to be supplied through the air conditioning to create a comfort zone for the occupants within. Therefore, a study on the heat transfer through the glass walls and its implication to the buildings’ cooling load would be necessary in order to understand the suitable approach of energy savings. The present research focuses on the effect of heat transfer through glass walls via conduction and solar radiation on buildings’ cooling load. Estimation on energy requirement with respect to solar radiation is calculated. This is done by calculation using equations and data provided in the ASHRAE Handbook. Experiments were also done using solarimeter to get the actual data for solar radiation with and without the presence of shading devices. From the results obtained, the effect of different orientation of the academic building in UTP on the total cooling load is studied. The direction of the sun which rises from the East North East to West North West affected the buildings in Zone 1 in the morning and also buildings in Zone 3 throughout the evening as the sun radiation is emitted directly to the buildings without any blockage. The occupied areas that are located under the main canopy of the academic complex are not exposed to the radiation as they are shaded. Actual measurements prove that the solar radiation emitted by the sun is much lower than calculated value. This is due to several factors which the movement of the clouds being the main reason. The use of shading materials such as window blinds and curtains further reduces the solar radiation up to 53 percent but also significantly reduces the amount of illuminance.