Development, experimental validation through infrared thermography and applications of a mathematical model of a direct-expansion solar-assisted heat pump with R290 based on energy, exergy, economic and environmental (4E) analyses

Abstract

The application of renewable sources, such as solar energy, and the use of ecological refrigerants in refrigeration and heating systems contribute to more sustainable development and the reduction of global warming. With this perspective, the main objective of this work is to develop, validate and apply a mathematical model based on the energetic, exergetic, environmental, and economic analysis of a Direct-Expansion Solar-Assisted Heat Pump for the production of Domestic Hot Water operating with R290. Environmental analysis is based on Total Equivalent Warming Impact and economic analysis is based on payback. The proposed mathematical model was validated on an experimental bench with R290 through infrared thermography applied to evaluate the temperature distribution in the evaporator. The influence of environmental parameters on the system with R290 is investigated through simulations. Among the environmental parameters investigated, solar irradiance was the parameter that most contributed to the increase in energy (69.3 %) and exergy efficiency (8.72 %). In addition, the increase in ambient temperature contributed more to the reduction of greenhouse gas emissions (88.6 %) but promoted the longest payback time for the system. Finally, in the tests performed, heating the water at a lower temperature (45 °C) compared to the higher temperature (65 °C) increased energy (25.0 %) and exergy efficiency (2.86 %), contributed more to the reduction of emissions, but increased the payback time.