Economic and environmental analysis of a novel rural house heating and cooling system using a solar-assisted vapour injection heat pump

An efficient low-carbon system is proposed to meet the heating and cooling demands of rural houses in cold regions. Mini-channel solar panels incorporating a novel multiple-throughout-flowing loop are used for heat collection, whilst a vapour injection air source heat pump (VI-ASHP) is innovatively combined with an underfloor heating and cooling system. To demonstrate the system, a multiple-throughout-flowing mini-channel solar thermal panel array of 36 m2 and a VI-ASHP of 40 kW heating capacity have been built and tested. Subsequently, mathematical models of the solar-assisted VI-ASHP system are established and compared with the experimental data. Based on the validated models, the energetic, economic and environmental performance is investigated under the typical weather conditions for a northern Chinese city (Taiyuan). The results indicate that, for a common rural house employing the proposed novel system, the proportion of the annual heat requirement, cooling load and hot water heating energy provided by solar thermal energy, photovoltaic energy and electricity from the power grid is 74.6%, 6.9%, and 18.5% respectively, thus giving a total energy supply proportion of 81.5% from solar energy. In addition, compared with a coal-powered system, our system has a cost payback period of 6.52 years and a life-cycle net cost saving of 56328.4RMB, thus the proposed system provides a greater economic performance. Furthermore, it can save 5tons of anthracite coal and reduce carbon emissions by 12.1tons annually. The proposed solar-assisted VI-ASHP has the potential to fulfil heating and cooling demands whilst reducing carbon emissions in northern China.