Modeling of solar-assisted ground-coupled heat pumps with or without batteries in remote high north communities

Many subarctic communities rely entirely on fossil fuels for their energy needs. Solar-assisted ground-coupled heat pumps (SAGCHP) can be a solution to integrate renewable energy sources into their energy portfolios. However, it is currently unknown how such systems could operate in the context of the high North (cold ground, extreme mismatch between insolation and heating need, electricity from diesel). The objective of the paper is to develop a detailed model of a SAGCHP heating a house in Nunavik (Quebec, Canada) in order to gain a better understanding of its potential and limitations. The solar assistance is provided by PVs. Simulations with and without electric storage (batteries) were run. A complex tradeoff between four different modes of operation was obtained depending on the conditions of the system at each time step. For the test case, results show that the ground experiences a weak long-term thermal depletion partly compensated solar energy, but that a significant portion of the PV power production is preferably used by the compressor or stored in batteries rather than stored in the ground as heat. Over ten years, the SAGCHP system reduced fuel consumption respectively by 38.2% (without a battery) and 59.1% (with a battery).

Automated summary

Many subarctic communities heavily rely on fossil fuels for energy, but solar-assisted ground-coupled heat pumps (SAGCHP) can integrate renewable energy sources. However, it is unclear how such systems would operate in the high North with cold ground, mismatched insolation, and diesel electricity. This paper aims to model a SAGCHP heating a house in Nunavik, Canada to understand its potential and limitations. Simulations were conducted with and without battery storage, revealing complex tradeoffs between four modes of operation. Over ten years, the SAGCHP system reduced fuel consumption by 38.2% (without battery) and 59.1% (with battery).