Utilization of U-shaped finned heat pipe heat exchanger in energy-efficient HVAC systems

Abstract

Energy-efficient Heating Ventilating and Air Conditioning (HVAC) system utilization is necessary to reduce energy consumption in buildings amid the supply difficulties of energy sources and the environmental impacts of high energy use. This study aims to investigate the utilization of a finned U-shaped heat pipe heat exchanger (HPHE) in a vertical configuration to reduce cooling and reheating energy in an HVAC system. The effectiveness of the U-shaped HPHE, coefficient of performance (COP) of the HVAC system coupled with U-shaped HPHE, and dehumidification capability are presented in this paper. The U-shaped HPHE was installed at the inlet fresh airstream ducts wrapped around the cooling coil, and tests were carried out with one-and two-row configurations arranged in eight heat pipes per row. The fresh air temperature and velocity across the evaporator section were varied at the ranges from 30 to 45 °C and 1.5 to 2.5 m/s, respectively. The results show that the two-row U-shaped HPHE significantly affects the precooling and reheating processes in the HVAC system compared with the one-row configuration. The two-row U-shaped HPHE can enhance the coefficient of performance (COP) by 39.9% over the HVAC without HPHE. The highest energy saving for precooling and reheating was 288.1 and 340.2 W, respectively, at 0.080 m3/s air volume and can reduce relative humidity by 21.6%. The investigation implies that the U-shaped heat pipe succeeded in becoming a solution to an HVAC system that requires cooling to reheat the HVAC system.