Heat and electric power production using heat pumps assisted with solar thermal energy for industrial applications

Abstract

Solar thermal devices with large installation areas represent technical, economic, and environmental challenges to design, construct, and operate them. Heat pump assisted with a solar thermal installation (STI) guarantee heat load supply at target temperature of a process, minimizing STI occupied area, environment impacts and associated costs. This paper deals with the design of two heat pumps, each one assisted with a STI. For designing solar network (which together the storage tank makes up the STI), lower irradiance levels than winter period are considered, guaranteeing continuous process operation. For designing each heat pump, two refrigerants with Ozone Depletion Potential of zero and Global Warming Potential of 7 (in one of them) are evaluated. This designing methodology is applied to a second-generation production of bioethanol case study. When heat is generated through a heat pump assisted with STI, the solar network absorber area is reduced by 85%, comparing with required area if only a STI produces heating. The same thing happens to generate electric power. Solar fraction value is one, 81,360 tons/year of not burned bagasse avoids 63,142 tons/year of greenhouse gases emissions. Still always guaranteeing the supply of energy to process, the impacts on environment and soil are minimized.