Analysis of the feasibility of applying a heat pump system for heating semiconductor clean rooms compared to a boiler system

Abstract

This study analyzed the feasibility of applying the heat pump system as heating equipment for semiconductor clean rooms by comparing it with a boiler. In this study, the annual heating load of the make-up air unit used for clean room heating in Korea was determined through TRNSYS modeling. The energy consumption of both the heat pump system and the boiler was analyzed using an engineering equation solver program and a theoretical calculation model. To implement the heat pump system for clean room heating, a two-stage cascade cycle is employed, utilizing a typical centrifugal chiller as the low-stage heat pump. Consequently, variations in the energy consumption of the cascade heat pump system, influenced by the temperature of the cooling water exiting the condenser of the typical chiller, were observed. After examining cooling water temperatures within the range of 35 to 39 °C with 1 °C intervals, it was determined that the system operated most efficiently at a cooling water temperature of 37 °C. Moreover, when a typical chiller is used as a low-stage heat pump, unlike the boiler, the heat pump system has the advantage of supplying chilled water used to remove heat from the facility. Thus, the application of the heat pump system leads to a reduction in the operating load of the typical chiller system, resulting in energy savings. Additionally, it was confirmed that the cooling water temperature at which the heat pump system can supply the most chilled water while also supplying hot water is 37 °C. After directly comparing the boiler and the heat pump system, it was determined that using the heat pump system resulted in a 11 % reduction in primary energy consumption, a 25 % reduction in carbon emissions, and a 59 % reduction in utility costs compared to the boiler. Furthermore, when considering the reduction in the operating load of the typical chiller system resulting from the chilled water produced by the heat pump system, a more significant energy-saving effect was demonstrated. At this time, the results indicated that the heat pump system reduced primary energy consumption, carbon emissions, and utility costs by 34 %, 44 %, and 70 %, respectively, compared to boilers. Hence, when applying a heat pump system as a heating solution, it is anticipated to exhibit superior performance compared to a gas-fired boiler. Nonetheless, practical implementation requires thorough consideration of diverse variables such as space efficiency and power supply and demand.