Feasibility of solar-geothermal hybrid source heat pump for producing domestic hot water in hot climates

• Published in: International journal of refrigeration Vol. 124; pp. 184 - 196
• Main Authors: Duarte, Willian M., Paulino, Tiago F., Tavares, Sinthya G., Maia, Antônio A.T., Machado, Luiz
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Ltd 01-04-2021; Elsevier Science Ltd
• Subjects: Ambient temperature; Analyse économique; Aquifers; Economic analysis; Ground-Source Heat Pump (GSHP); Groundwater; Heat exchangers; Heat pumps; Heat transfer; Hot climates; Hot water; Hybrid systems; Hybrid-Source Heat Pump (HSHP); Pompe à chaleur géothermique (GSHP); Pompe à chaleur hybride (HSHP); Pompe à chaleur à assistance solaire (SAHP); Pumps; R290; Solar energy; Solar radiation; Solar-Assisted Heat Pump (SAHP); Studies; Temperature; Topology; Water temperature; Water wells; Hybrid-Source Heat Pump (HSHP); Solar-Assisted Heat Pump (SAHP); R290; Economic analysis; Pompe à chaleur hybride (HSHP); Ground-Source Heat Pump (GSHP); Analyse économique; Pompe à chaleur géothermique (GSHP); Pompe à chaleur à assistance solaire (SAHP)
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2020.12.022

•The system used R290 (an environment-friendly refrigerant).•The results showed that the COP of an HSHP mode is better than GSHP, ASHP, SAHP for most environmental conditions.•The best payback was obtained using a SAHP mode.•A case study was also performed considering the climate of three Brazilian cities.
This work presents a study for examining the viability of Solar Geothermal Hybrid Source Heat Pump systems to produce domestic hot water in Brazilian-type climates. The system considered has an open-loop ground-water (aquifer) and an uncovered solar collector that can be used in a separate or connected in series topology. The refrigerant chosen for the heat pump was R290 (propane). This theoretical analysis was made using lumped models for each component of the system. The influence of ambient temperature, solar radiation, water well depth and ground water temperature in the COP, payback and collector efficiency were analyzed. The results showed that the COP of a Hybrid Source Heat Pump was better than other types of heat pump configurations for most environmental conditions, but the best payback was obtained using a Solar-Assisted Heat Pump. A case of study was performed for three different cities in Brazil and the paybacks found were in the range of 2.28 and 4.45 years. The results of COP and payback were compared with other papers and the maximum difference was 10% and 12%, respectively. Considering the scenario of a house that already has a water well, thereby eliminating the drilling cost, the best payback is obtained using a Ground-Source Heat Pump.