Energy and thermal performance of heat pipe/cooling coil systems in hot-humid climates

The objective of this study is to evaluate the magnitude of reduction in cooling and reheat energy when a heat pipe system is incorporated with the cooling coil of an air-conditioning system. The heat pipe/cooling coil (HP/CC) system performance is determined by several parameters that are related to both the air-conditioner cooling coil and the heat pipe physical characteristics as well as the condition of the air entering and leaving the system. In order to appreciate the impact of these parameters and their relative influence on energy consumption and the required indoor air conditions, a simple mathematical model incorporating the parameters of HP/CC is formulated. The model describes the overall system performance at varying entering and leaving air conditions. The model is then applied to a case study as an example of an application to investigate these relationships for a better understanding of the system behaviour and the influencing design parameters. It is evident that due to the coupling nature of the heat pipe and the cooling coil actions, a unique system performance will be obtained for each combination of heat pipe effectiveness and cooling coil by-pass factor. A proper selection of both the heat pipe and the cooling coil characteristics is found to be necessary for a satisfactory performance under the given operating conditions. Copyright (C) 2000 John Wiley and Sons, Ltd.