Solar assisted gas cooler integrated system, theoretical and experimental analysis

In recent years, concerns about the health of the Earth have increased public awareness and attention to "green" solutions. Within this framework, we present a study to investigate an innovative CO2 gas cooler which can reduce primary energy consumption. In the refrigeration industry the use of CO2 as the working fluid is increasing continuously and the opportunity to use highly efficient gas coolers is crucial for sustainable plants. LU-VE, in cooperation with Politecnico di Milano, has developed a new range of CO2 gas coolers equipped with solar photovoltaic panels which can produce a large fraction of the energy required to power the electronically commutated (EC) fans of the gas cooler. We did an intensive theoretical study, supported by an experimental campaign, to define the optimum size of the solar panels and the bank of batteries. The system is equipped with an array of batteries and a full regulation system, maximizing the number of working hours using solar energy. The paper describes the new product and the numerical model capable of predicting both the electrical energy needed by the gas cooler and that produced by the PV panels. The experimental campaign for the model validation is also illustrated. The PV panels are an integral part of the CO2 gas cooler, creating a packing device connected both mechanically and electrically to simplify installation on the work site. Finally, a techno-economic analysis is performed, to evaluate the pay-back period in different geographic areas, optimizing the configuration in terms of PV panel area and battery bank size, also considering the possibility of supplying any surplus electricity directly to the grid.