A novel solar-assisted ground-source heat pump (SAGSHP) with seasonal heat-storage and heat cascade utilization: Field test and performance analysis

Abstract

To maintain the energy quality with high temperature and reduce the energy loss of seasonal heat-storage in solar-assisted ground-source heat pumps (SAGSHPs), a novel SAGSHP system with the heat-cascading of borehole heat-exchangers was designed and its field-test was conducted in this paper. The borehole heat-exchangers were divided into two regions: the core region and the peripheral region. The core region can maintain a high temperature (e.g. 45 ℃), which is much higher than in previous studies, and the heat from this region can be used directly, without the operation of a heat pump. The field-test was conducted in a community in the province Shandong, China. The results indicate that a sufficient soil-temperature gradient (the temperature is high in the core but low at the periphery) can be created and maintained.The monthly averaged borehole-wall-temperature difference between the borehole heatexchangers (BHEs) at the core and the periphery can be as high as 30.1 ℃. This means that both cascaded heat-storage and heat-utilization can be realized. In addition, an average performance of CCOP=5.15 and SCOP=4.66 can be achieved. Compared with previous studies, despite the lower CCOP, a higher SCOP can be attained, thanks to heat cascade storage andutilization. The novel approach described in this paper represents a viable alternative for space heating in North China.

Energy and economic evaluation of a solar assisted ground source heat pump system for a north Mediterranean city

“…The type of solar collectors used for the studies of SAGSHP systems range from flat plate collectors (FPC) [16] to PVT collectors [17], while geothermal heat exchangers (GHE) include borehole heat exchangers (BHE) [18] and novel very shallow borefields of some meters deep [11]. These can be paired in numerous combinations, on top of many available system topologies (hydraulic connection of systems) and control strategies [19][20][21][22][23]. It can be concluded that, SAGSHP systems is a complex technology involving many aspects and their design is a site-specific matter, with no established approach.…”

A New Solar Assisted Heat Pump System with Underground Energy Storage: Modelling and Optimisation

“…The use of solar-assisted ground source heat pumps is presented by Sun et al in [2]. To maintain energy efficiency and allow the annual average Coefficient Of Performance (COP) of the heat pump, it is equal to 4.66.…”

The design of a seasonal heat storage system with a geothermal heat pump for a residential building in Tehran

“…Thermal energy storage offers various opportunities in the design of renewable energy systems. One of those is seasonal storage of thermal energy under the ground, as well as using solar-assisted ground-source heat pump (SAGSHP) which is a kind of innovative approaches to preserve energy quality, reduce the demand for fossil fuel energy and minimize the waste of energy derived from heating and cooling of the buildings (Reda, 2015; Carbonell et al , 2014; Sun et al , 2020). The idea of using ground source heat pump (GSHP) systems was developed in the late 1940s (Crandall, 1946; Ingersoll, 1948).…”