SolairHP Project: First results of summer campaign

The presented work deals with the Solair-HP project, regarding the development and testing of an innovative solar assisted trans-critical CO2 heat pump. It has been developed aiming at reducing the electrical consumptions by means of exploitation of the solar thermal source. In fact, it is equipped with an innovative proprietary photovoltaic hybrid solar panel integrated with a tube heat exchanger to be used during winter as auxiliary heat source. With this technology it is possible to avoid the use of the air finned coils exchanger, and thus to reduce the issues related the ice formation on the fins – i.e. frosting - and the consumptions due to the finned coil’s fan. Moreover, the use of CO2 with its low GWP (Global Warming Potential) together with the possibility to produce electricity using the PVT (PhotoVoltaic and Thermal) makes this solution very eco-friendly, with a low environmental impact and able to fully exploit the renewable energy coming from the sun. It is possible to use also CO2 arising from industrial wastes. The machine can operate in up to six different modes basing on what it is needed by the users, and it can produce at the same time DHW (Domestic Hot Water) and cold water for climatization. The total thermal capacity of the system ranges from 7 kW for cooling, up to 10 kW for heating and it has been developed to be installed in a semi-detached house. For its placement, the heat pump, requires about 10 square meters of free space. The heat pump has been installed in the Casaccia research centre of ENEA in open field, in order to simulate the real operating conditions. A dedicated auxiliary system has been projected and installed to test the heat pump in all the different configurations and at different powers. It is possible to regulate the input/output temperatures as well and the mass flow rates to get a constant and precise value to fulfil the regulation requirements during tests. In the presentation the operating modes of the heat pump are described as well as its advantages over a traditional system. Moreover, some results of its capability are showed for a summer campaign, where more than 5000 working points were recorded. The heat pump performances were analysed at different fan speeds, compressor frequency and lamination valve opening degrees. Its ERR (Energy Efficiency Ratio) and cooling power capacities are described showing preliminary results. Mixed usage tests (cold and hot water) are currently ongoing, and they will be ended before the beginning of winter. The more interesting winter tests, with the heat pump using the PVT system, will be run during next winter and the results will be published further on. The project is currently ongoing and includes among its partners IPSE-lab at ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development), the University of Padova and ENEX (a private corporation, being project leader too). The ENEA IPSE laboratory deals with the Process Engineering and Systems for Energy Decarbonization, belonging to the Division for Energy Production, Storage and Use Division, under the Department for Energy Technologies and Renewable Energy Sources. The project is co-founded by the Italian Ministry for Economic Development for a total funding of 1.4 M€.