Comparison of Solar Thermal Collectors and Solar PV Heat Pump Systems

Abstract This paper presents a comparison between traditional flat plate solar thermal collector systems and solar photovoltaic (PV) heat pump systems. The purpose of this analysis was to determine whether or not heat pump technology has matured to the point that a solar PV system paired with a heat pump could outperform a traditional solar thermal flat plate collector system. To this end, two systems with identical panel footprints of 7.6 m2 (82 ft2) were modelled and analyzed at four different locations being Los Angeles CA, Phoenix AZ, Seattle WA, and Denver CO. The expected energy production and Levelized Cost of Energy (LCOE) for both systems at these locations were determined. The solar fraction for the solar thermal collector systems and PV heat pump systems at the four locations studied were found to be f = 0.44 and f = 0.99 in Los Angeles, f = 0.44 and f = 1.00 in Phoenix, f = 0.21 and f = 0.62 in Seattle, and f = 0.34 and f = 0.90 in Denver. As such, it is evident that the solar PV heat pump systems produced more thermal energy than the solar thermal collectors at all locations tested. The LCOE for the solar thermal collector systems and solar PV heat pump systems at each location were found to be 48.42 ¢/kWh and 36.57 ¢/kWh at Los Angeles, 55.37 ¢/kWh and 36.13 ¢/kWh at Phoenix, 81.47 ¢/kWh and 97.29 ¢/kWh at Seattle, and 52.27 ¢/kWh and 67.50 ¢/kWh at Denver. From these values, it can be seen that the solar PV heat pump systems have a lower LCOE in the warmer climates where ground source heat pumps are not needed but have slightly higher LCOE values in cooler climates where they are. As such, this study has found that solar PV heat pump systems have matured enough to outperform solar thermal flat plate collectors in most situations.