Experimental investigation on the performance of transcritical CO2 ejector–expansion heat pump water heater system

By Yinhai Zhu, Yulei Huang, Conghui Li, Fuzhen Zhang, P. Jiang. Energy Conversion and Management, 2018

137 citations recorded by the source corpus.

Abstract The effects of hot-water outlet temperature, compressor discharge pressure, compressor rotation speed, and expansion valve opening on the ejector and overall system performance were investigated for tap water outlet temperatures ranging from 50 to 90 °C. The coefficient of performance (COP) of the ejector–expansion heat pump system reaches 4.6 when the tap water outlet temperature is 70 °C, which is 10.3% higher than the corresponding basic cycle. Compared to the basic system, adding an ejector is more effective for the generation of high-temperature hot water. The COP of the ejector–expansion heat pump system increases; however, the COP improvement ratio ΔCOP decreases with the increase in the discharge pressure because of lower pressure lift ratio and ejector efficiency. The COP and ΔCOP increase when the compressor rotation speed decreases under our test conditions; simultaneously, the heat capacity decreases.

Subfields: Biomedical Engineering, Building and Construction, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/785950f4611df332218fd9e69647527b4c578606