Researchers in Jordan have developed a solar-assisted heat pump system for swimming pool heating at a hotel in the coastal city of Aqaba. They found that the system has a payback time of just 1.94 years and that total profits after ten years of operation can reach about $1.88 million.
January 3, 2022
A group of scientists from Mutah University in Jordan and Amman-based Golden Energy Company have evaluated the energy and economic performance of a PV-powered heat pump system used to heat the swimming pools of a hotel building in the coastal city of Aqaba.
Their simulation assumed the hotel had an average annual electricity consumption of about 6.5 MWh and total electricity costs of JOD591,000 (US$834,000) per year. They assumed that a 408.2 kW PV array with a five-degree pitch will be installed on the hotel’s rooftops. The cost of the PV system was estimated at 244,920 JOD or 600 JOD ($846.20) per installed kilowatt. The total cost of the solar powered heat pump system was estimated at JOD 360,920.
The hotel has a family pool with an area of 310 m2; the main pool with an area of 515 m2; and a spa pool with an area of 380 m2. A significant amount of heat is required between October and March to keep both the indoor and outdoor pools warm. A heat transfer model was used to estimate the performance of the swimming pool heating system.
The model takes into account evaporative and convective heat losses as well as conduction losses, radiation losses and heat losses of the make-up water. “The pool’s ability to dissipate or absorb heat is entirely determined by its location, environmental conditions and time of day or night,” the scientists explained. “The heat transfer balance is also affected by the location of the pool, whether indoors or outdoors.”
It has been found that evaporative heat losses have the greatest impact in all swimming pools, and the thermal energy generated by the PV-powered heat pump, which can provide hot water at temperatures from 35 to 60 degrees Celsius, is mainly used to recover these losses. The effect of other losses, however, was found to be minimal.
According to the scientists, the electricity provided by the heat pump system was able to significantly reduce the energy requirements for electric heating for all months of operation of the family and main pool. Significant savings were also achieved in the spa pool, which can also be heated by a steam boiler powered by liquid gas. Annual savings were estimated to be JOD26,506 and JOD43,891 for the family and main pools, respectively, and JOD17,328 for the spa pool.
“The hotel’s annual electricity requirement is 6,500 MWh with a total cost of 591,000 JOD per year compared to the proposed PV installation which generates approximately 786 MWh per year. It can be calculated that the net electricity consumption would be 5,714 MWh per year for a total cost of 514,000 JOD, that is…[s] The proposed system will save about JOD 185,850 annually from the total electricity bill,” stressed the Jordan Group. “The cash flow value turns positive at the end of the second year and remains positive throughout the ten-year evaluation period. The reason for this is that the total energy production of the system is large, while the initial cost is relatively low.”
The proposed heat pump system was found to have a payback period of just 1.94 years and total profits after ten years of operation were reported to be JOD1,338,931 (US$1.89 million). “A superficial examination of the economic factors of the solar project leads to the conclusion that it is economically justified,” conclude the scientists.
The system design was described in the paper Evaluation of the energy efficiency and economics of a photovoltaic heat pump system, published in Results in Engineering.
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