China’s new hybrid heat pump slashes energy costs by 55% and grid reliance by 75%
Researchers in China have just unveiled a new hybrid wind-solar heat pump that significantly improves energy efficiency and can reduce household energy costs by more than 50 percent.
The innovative heat pump that runs on both wind and solar power was developed by a team of scientists from Shenyang Jianzhu University and Shanghai Jiao Tong University in China.
The new system enhances energy efficiency in residential homes by integrating both thermal and electrical energy storage.
It is also supported by seasonal energy-interaction framework, which features spring ground-source precooling, summer cooling, autumn ground-source preheating and winter heating.
What’s more the the researchers developed an optimized energy management strategy for the heat pump, which they modeled using advanced software tools such as TRNSYS and SketchUp.
Heat pump breakthrough
According to the scientists, the project was based on a low-energy residential building (LERB) in Shenyang, northeastern China. The region’s freezing winters and hot summers provided ideal conditions to test energy performance.
The two-story, 3,603-square-foot (334.8-square-meter) building featured about 1,400 square feet (130 square meters) of roof space suitable for solar panels. The hourly solar radiation at the site ranged from 0 to 0.3 kilowatt-hours per square meter (kWh/m2) over the year.
The researchers integrated 550-watt (W) photovoltaic (PV) modules and three-kilowatt (kW) wind turbines into the system. The setup was supported by a 40-kilowatt-hour (kWh) battery and a water tank with phase-change materials (PCM) for thermal storage.
Meanwhile, the system used two heat pumps, including a ground-source heat pump (GSHP) and an air-source heat pump (ASHP). It additionally included ground-source exchangers (GSEs) to transfer heat between the system and the surrounding soil.
The GSHP drew heat from underground during winter and released excess heat back into the ground during warmer months. The ASHP, in turn, supplemented the system when environmental conditions changed.
A sustainable heat solution
To improve efficiency, the team introduced a two-stage optimization process. The first stage using the on-dominated Sorting Genetic Algorithm (NSGA-II algorithm) determined the ideal system configuration.
The second stage, which was powered by particle swarm optimization, managed battery charge levels on a weekly basis. This allowed the system to automatically balance renewable power generation, heating demand and battery storage, depending on the season.
The researchers then tested four setups to evaluate system performance. They started with a basic system and gradually added the interaction strategy, ASHP, two-stage optimization, PV and finally wind generation.
They discovered that the optimized hybrid system reduced the levelized cost of energy (LCOE) by at least 54.7 percent and increased overall performance by four percent compared to baseline systems. The system independence factor (SIF), a measure of grid reliance, dropped by 75 percent.
Over 10 years, soil temperatures around the ground exchangers fell by only 0.76 degrees Fahrenheit (0.42 degrees Celsius). It helped prevent ground temperature imbalance in long-term GSHP operation.
The optimal wind–PV heat pump setup included 13.12 kW of solar capacity, two wind turbines, 25.46 kWh of battery storage, a 6.17-kw ground-source heat pump and a 29.7-square-foot (2.76-square-meter) water tank.
The study has been published in the journal Energy.