Study on the Optimal Solar Fraction of Solar Water Heating System Combined with Heat Pump Unit for Hot Water Supply in Residential Buildings

This paper presented a new optimal model in which the solar fraction is a key factor that has the double impact on both first cost and operating cost of the compound system, and proposed the optimal operating control strategies based on the characteristic of hot water supply demand in residential buildings, compiled a calculation program using C++ and conducted optimal solving, finally analyzed impact of solar fraction on system energy efficiency and economy and discussed the adaptability of system application.