Cooling coil optimisation in hot and humid climates for IAQ and energy considerations

Abstract

In hot and humid climates, the primary challenge is cooling and dehumidification, which needs to be achieved in an energy efficient manner in order to provide adequate ventilation and maintain good indoor air quality. This necessitates a careful consideration of all the related design parameters both on the air handling unit side as well as the chiller side. In this regard, the design of cooling coil plays an important role in obtaining optimal performance. In this paper, the water-side parameters of the cooling coil are studied using a standard coil selection programme with the view of fulfilling the design requirements of airflow, cooling capacity and indoor environmental conditions. Conventional design practices of 6 and 7 °C chilled water supply (CHWS) temperatures and 6 and 7°C chilled water ΔTs are used as reference cases and the following three variations are explored - a) increasing CHWS temperatures and reducing chilled water ΔTs b) larger chilled water ΔTs with constant CHWS temperature and c) increasing CHWS temperature and constant CHW T. Energy simulations are also done to estimate the overall energy performance in these various combinations.