Evaluation of efficiency of hybrid geothermal basket/air heat pump on a case study winery based on experimental data

Abstract

In wine-making sector, processes require high cooling loads for short periods; in addition, the climate-dependent energy needs have to be added. In Southern Europe latitude, a combination of Air Source Heat Pumps to cover peak cooling loads and lpg-fired boiler for winter heating is the most common solution for wineries in countryside, which are usually off-gas grid. Shallow geothermal energy coupled to heat pumps could represent a good solution for wine-making sector, and some applications exist in different countries. Nonetheless, because of electricity price and the displacement between high cooling and low heating loads, the investment cost for the geothermal field often is not justified. Some cheap and shallow solutions as geothermal baskets can help to reduce investment costs, but their capacity is limited, so to cover the entire cooling loads represents a significant task. On the other hand, a combination of different technologies could bring to interesting results in terms of cost and CO2 savings. The paper presents an efficiency evaluation of a hybrid solution integrating a Ground Source Heat Pump coupled to geothermal baskets with an Air Source Heat Pump. An experimental campaign − Thermal Response Test − was conducted in the courtyard of a winery. A simulation program tailored on the test results has been realised for the specific case study, in order to optimise the integration between two plants. It was then possible to determine the energy savings connected to the use of the hybrid solution with respect to alternatives, to cover the entire heating and cooling needs of the winery.