Cooling load estimation using cooling load temperature different (CLTD) method for ergonomic lecture room

Abstract

Accurate cooling load estimation is essential for achieving thermal comfort and energy efficiency in air-conditioned buildings, particularly in educational facilities with varying occupancy levels. This study estimates the cooling load of a lecture room (BK6) at UniCiti Alam, Universiti Malaysia Perlis, using the Cooling Load Temperature Difference (CLTD) method. Both external and internal heat gains—including heat transfer through walls and glazing, solar radiation, occupants, lighting, equipment, and air infiltration—were evaluated based on local climatic conditions and building characteristics. Cooling load calculations were performed for cases with and without corrected CLTD values to assess their impact on total heat gain. Results indicate that the maximum cooling load occurs at 1:00 p.m., with a total cooling load of 23.62 kW (32 HP) when corrected CLTD values are applied and 24.60 kW (33 HP) without correction. The difference between the two cases was found to be relatively small, at approximately 0.9 kW. The findings confirm that the existing air-conditioning capacity is insufficient to meet the actual cooling demand under full occupancy. In addition, an Excel-based calculation template was developed to facilitate practical cooling load estimation using the CLTD method. The proposed approach provides a reliable and user-friendly tool for Heating Ventilation, and Air-conditioning (HVAC) system sizing and can support energy-efficient design and operation of lecture rooms and similar buildings.