Scientists in China have developed a novel PV-powered cooling and heating system that combines a water-cooled gas cooler and an air-cooled gas cooler. The system went through a series of simulations and showed it can potentially achieve a coefficient of performance of up to 7.34.
A group of researchers from China has developed a novel heating and cooling system that uses solar PV and battery storage power.
“In this study, an eco-friendly combined heating and cooling system integrated with solar photovoltaic and energy storage is proposed for a commercial supermarket, and the waste heat of the compressor is also recovered for hot water production,” the scientists explained. “The hot water produced by this system can be used in many applications, such as bathing, heating, and other scenarios.”
The scientists simulated the thermodynamic performance and carbon emissions of the system across different regions in China.
The system’s novelty lies in its combination of water-cooled gas cooler (WC) and air-cooled gas cooler (AC). It further uses throttling valves (TVs), an evaporator, a water pump, a PV panel, a battery, a photovoltaic inverter, and a photovoltaic controller. It was assumed to work in a supermarket of 1,866 m2, where the system is at a stable state and the superheat degree of the compress is set to 5 C.
In the proposed system configuration, the working fluid in the system evaporates in the evaporator before entering the compressor and being compressed, with the high-temperature working fluid after compression entering the water-cooled condenser to heat the tap water. The tap water is then heated into high-temperature hot water, which is then pumped into the hot water storage tank as domestic hot water.
“After preliminary cooling in the water-cooled gas cooler, the working fluid enters the air-cooled condenser to dissipate heat to the atmosphere. Then, the working fluid is further cooled and enters the throttling valve. Subsequently, the low-temperature and low-pressure working fluid enters the evaporator to complete the refrigeration cycle,” the academics further explained.
The novel system was numerically simulated across five cities in China, namely Harbin, Beijing, Shanghai, Kunming, and Guangzhou. It was also simulated against a reference system that did not include PV components and lacked an AC, only including the WC for heating.
“The coefficient of performance (COP) of the system initially increases and falls with the rise of discharge pressure, reaching the maximum COP at the optimum discharge pressure. When the discharge pressure is 8.13 MPa, the maximum total COP is 7.34,” said the team. “As a city’s latitude increases, its overall electricity usage tends to decrease. The energy usage can be decreased by 61.8~76.2% compared with the base system.”
The analysis also showed that the emissions reduce with the increase in the latitude of the city. Overall, the carbon emissions are reduced by 51.3~63.3% when the novel proposed system is adopted. “The novel system can lower the discharge pressure compared with the baseline system. The higher ambient temperature, the discharge pressure is reduced more significantly, which can be scaled down to 12.28% at the ambient temperature of 40 C,” the researchers concluded.
The system was presented in “Eco-friendly combined heating and cooling system integrated with solar photovoltaic and energy storage: Thermodynamic performance and carbon emission evaluation,” published in Case Studies in Thermal Engineering. Scientists from China’s Guangzhou Automobile Group, Beijing Jiaotong University, and Tianjin University of Commerce conducted the research.
This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.
Popular content
Source link