Wrap-around loop pulsating heat-pipe heat exchanger for enhancing the energy efficiency of high-tech cleanroom HVAC systems

To maintain strict temperature, humidity, and cleanliness requirements, the cleanrooms of high-tech semiconductor fabrication plants have heating, ventilation, and air conditioning (HVAC) systems, which require substantial amounts of energy. To reduce energy consumption, this study proposes using a wrap-around loop pulsating heat pipe (WLPHP) heat exchanger comprising a pulsating heat pipe for precooling high-temperature outdoor air to reduce relative humidity. The heat absorbed by the heat-pipe evaporator is then transferred to the condenser and released, reducing the energy required to subsequently reheat the air with an HVAC system. The experimental results reveal that the system reduces the required reheating energy and increased the moisture removal rate per unit energy consumption by an average of 24.8% and 33% compared with a typical heat exchanger. Hence, using the WLPHP heat exchanger in HVAC systems could provide large energy savings.