Post occupancy study to validate the thermal comfort performance of chilled ceiling systems for an energy efficient building in the tropics
Tan, Wei Zhi
Date of Issue2016
School of Civil and Environmental Engineering
Energy Research Institute @ NTU
The warm tropical climate in Singapore calls for high demands in air-conditioning to maintain comfortable indoor environments for building occupants. This has placed air-conditioning as the largest energy consumer in buildings, taking up half of all building energy requirements. The rising concern in environmental and energy resource sustainability has thus motivated the need to find new energy efficient air-conditioning solutions for building cooling needs. The most common air-conditioning system adopted by buildings in Singapore is the Variable Air Volume system. This system was designed to handle large volumes of air, which consequently results in its high energy consumption. Hence in recent years, an increase in studies on air-conditioning with better energy efficiencies is observed in the tropics. A promising candidate to appease today’s concerns is the chilled ceiling system that has been popular in the temperate climates around the world, in terms of its energy efficiency and thermal comfort performance. Energy efficiency is achieve by the reduced mechanical ventilation requirements. Chilled ceiling systems also gets an upper hand with its additional advantages in thermal comfort and operational performances. It was realised that many studies of chilled ceiling systems including a feasibility study conducted in Energy Research Institute @ NTU, has not considered the possibility of deviation in thermal comfort due to changes in weather or seasonal patterns throughout the year. Thermal comfort evaluation done previously might hence be incomprehensive to an extent. Therefore, the objective of this paper is to verify if changes in weather patterns between the dry and wet periods affects thermal comfort in a chilled ceiling cooled space. Thermal comfort evaluation was conducted using the CBE thermal comfort tool, thermal environment satisfactory survey and AC’s performance compliance evaluation based on ASHRAE Standard 55-2013 (ASHRAE, 2013) and Singapore Standard SS553:2009 (SPRING Singapore, 2009). It was revealed that there is a significant change in thermal comfort between the different weather types. Although the system was qualified to be able to provide satisfactory thermal comfort, there were still minor operational issues identified during dry periods. In conclusion, observations proved that the thermal comfort in a chilled ceiling cooled office changes with weather patterns variations. Hence, it is recommended that future studies conduct thermal comfort evaluation for different weather periods to yield a comprehensive analysis. Finally, to increase the adoption of the system, future research are encouraged to expand on new areas of chilled ceiling system studies which includes the performance stability, maintenance cost and scale applicability of chilled ceiling systems.
Final Year Project (FYP)
Nanyang Technological University