Thermal Comfort and Energy Analysis of Fan Coil Unit Cooling Systems in Tropical Buildings

Overcooling is a frequent occurrence in Malaysian buildings, particularly in libraries and classrooms. This study evaluates the thermal comfort of a fan coil unit (FCU) installed in a case study room in Malaysia’s hot and humid climate to detect the problem. On the basis of measurement factors such as temperature, humidity, and airflow, a data acquisition system consisting of sensors and a data logger was selected and installed in the case study room. The measurement data were collected from 8:00 a.m. to 5:00 p.m. for the duration of one week. The cooling load distribution of the case study room was detected from measurement data analysis. 52% of the overall cooling load (9.4 kW) was related to latent loads and 48% to sensible loads. Measuring results indicate that the seminar room’s temperature and relative humidity under the FCU application were 24.3 °C and 77.1%, respectively, values that did not correspond to the thermal comfort level (25 °C and 50% humidity). As a result, it was determined that if room humidity is set to 50%, the room temperature will reach 17 °C, leading to the space being over-cooled. An optimised FCU has been built to achieve the ideal interior atmosphere. Compared to the current FCU, the improved FCU consumes 1.40 times more energy.