Application Of Solar-ground Coupled Heat Pump With Energy Storage Hot Water System In Residential Building

Because of global energy crisis, the development and utilization of renewable energy has become ahotspot. Solar energy therefore attract everyone’s attention as renewable and clean energy."integration ofsolar energy and building " has become an important issue in the field of building energy conservation. Inthis paper, solar-ground coupled heat pump with seasonal energy storage system was discussed. Thissystem bases on integration of solar energy and building. It increases the depth and breadth of solar energyutilization. And this system overcomes the disadvantages due to solar energy’s low density and instabilitycaused by change of weather and season. SGHPES increases the efficiency of solar energy system.Compared with conventional solar water heating systems, solar-ground coupled heat pump withseasonal energy storage hot water system includes the core of the solar energy collector system, heat pumpsystem and seasonal energy storage system. This paper discussed three different methods of integration ofsolar energy and building: centralized collector-centralized storage, centralized collector-householdstorage and household collector-household storage. Centralized collector-centralized storage is the mostconvenient way to combine with heat pump system and seasonal energy storage system. Due to its simplestructure, low cost and facilitate management, centralized collector-centralized storage should be the firstchoice. Seasonal energy storage is divided into water thermal energy storage, aquifer thermal energystorage, gravel/water thermal energy storage and ground thermal energy storage. Ground thermal energystorage is our main research object, due to its low cost, low environmental requirements and no landoccupation. In order to match the seasonal energy storage system, ground source heat pump system ischosen.This paper studied the usage of solar-ground coupled heat pump with seasonal energy storage hotwater system in residential building. As an example, a SGHPES hot water system was designed for aresidential in Xi’an. Abundant solar energy in sunny days will be stored in the ground. In rainy days and inwinter, when the solar energy collector system can not provide enough energy for water heating, the heatpump system will startup and extract the stored energy from the ground. The pipes buried underground areused to inject and extract energy, and switched between the two states through control system. In this paper,flat-plate collector, U-shaped pipe vacuum tube collector and heat pipe vacuum tube collectors arecompared. The results showed that, in this project, the flat-plate collector covered54m2, and heat pipevacuum tube collector covered50m2, while U-shaped tube vacuum tube solar collector covered7~, which was much larger than the previous two. The cost of flat plate collectors is the lowest. According topreliminary design and calculation, annual energy savings of the system is127454.144MJ, annual simplecost of energy-saving is Rmb17483.58, carbon dioxide emission reductions in the life of the system is50122.82kg, auxiliary heat cost is30.43%lower than gas and77.94%lower than electric.