Thermodynamic analysis of photovoltaic/thermal heat pump based on phase change slurry

Abstract

To explore the feasibility and relative advantages of phase change slurry (PCS) as operating working medium, a solar hybrid vapor compression heat pump based on phase change slurry (PCS-PV/T-VCHP) is constructed by directly combining PCS as operating fluid with evaporator. Furthermore, performance of PCS-PV/T-VCHP under different initial conditions is studied and demonstrated by simulation method. PCS as operating medium has higher PV/PT and total efficiencies, which respectively reach 15.46%/83.17% and 98.63%. PCS has multiple advantages for VCHP applications due to high heat storage density and stable heat release. Under given initial conditions, PV/PT efficiencies are 15.15%–15.77%, 67.63%–84.03% respectively, and the maximum solar efficiency are 98.81%. The minimum and maximum values of VCHP coefficient of performance (COP) reach 2.23 and 5.82 respectively, and total COP is distributed in the range of 3.02 and 23.71. The maximum electrical exergy efficiency and thermal exergy efficiency are 15.77% and 7.57% respectively, and total exergy efficiency ranges from 16.61% to 23.25%. PCS-PV/T-VCHP shows good heating performance in typical cities, COP reaches 1.99–5.87 in selected cities. The feasibility of using PCS as operating fluid to supply heat has been confirmed, and PCS-PV/T-VCHP has significant performance advantages, low emissions and good economy.