Experimental investigation of novel heat exchanger for low temperature lift heat pump

In this paper, the thermal and hydraulic performance of a novel low temperature lift heat exchanger (LTLHX) was experimentally investigated. The novel LTLHX was developed to improve the performance of the conventional plate type heat exchanger (PHX) under low temperature lift operating conditions. The optimized novel LTLHX was fabricated and investigated experimentally with various operating conditions. The heat transfer coefficient correlation and friction factor correlation of the water-side in the novel LTLHX were formulated from the experimental data. The overall heat transfer coefficient of the novel LTLHX with ammonia ranged from 1300 to 2000 W K^-1 m^-2, and the pressure drop per length of the water-side ranged from 4 to 10 kPa m^-1. The refrigerant-side heat transfer coefficient ranged from 2900 to 5000 W K^-1 m^-2, and water-side heat transfer coefficient ranged from 3900 to 5100 W K^-1 m^-2. The overall heat transfer performance of the novel LTLHX was more than double that of the PHX at the same operating conditions. Moreover, the water-side pressure drop of the novel heat exchanger was drastically lower than that of the PHX. It was due to the balanced thermal and hydraulic performance of the novel heat exchanger.