PV-Powered Heating and Cooling System for Supermarkets: A Breakthrough in Sustainable Energy Solutions

A team of Chinese researchers has successfully developed an innovative heating and cooling system that harnesses the power of solar energy and battery storage. This cutting-edge technology represents a significant step forward in sustainable energy solutions for commercial buildings.

The scientists behind this project explained, "In this research, we propose an environmentally friendly integrated heating and cooling system for commercial supermarkets, which combines solar photovoltaic technology with energy storage capabilities. Moreover, the system recovers the waste heat generated by the compressor to produce hot water, which can be utilized in various applications, including bathing, space heating, and other practical scenarios." To comprehensively assess the system's potential, the researchers conducted simulations to analyze its thermodynamic performance and carbon emissions across diverse regions in China.

The uniqueness of this system lies in its intelligent integration of a water-cooled gas cooler (WC) and an air-cooled gas cooler (AC). Additionally, it incorporates essential components such as throttling valves (TVs), an evaporator, a water pump, a PV panel, a battery, a photovoltaic inverter, and a photovoltaic controller. The system was modeled to operate in a 1,866-square-meter supermarket, assuming a stable operational state with the compressor's superheat degree set at 5°C.

In the proposed system design, the working fluid first evaporates in the evaporator before entering the compressor for compression. The high-temperature working fluid resulting from compression then flows into the water-cooled condenser, where it transfers heat to tap water, heating it to a high temperature. This heated water is subsequently pumped into a hot water storage tank, ready for use as domestic hot water.

The researchers further elaborated on the system's operation: "After undergoing preliminary cooling in the water-cooled gas cooler, the working fluid proceeds to the air-cooled condenser, where it releases heat into the atmosphere. Following this, the fluid is further cooled and directed to the throttling valve. Finally, the low-temperature and low-pressure working fluid re-enters the evaporator, completing the refrigeration cycle."

To evaluate the system's effectiveness, the researchers conducted numerical simulations in five major Chinese cities: Harbin, Beijing, Shanghai, Kunming, and Guangzhou. They also compared the results with a reference system that lacked PV components and an AC, relying solely on a WC for heating purposes.

According to the research findings, "The system's coefficient of performance (COP) initially rises and then declines as the discharge pressure increases, achieving its peak value at the optimal discharge pressure. When the discharge pressure reaches 8.13 MPa, the maximum total COP reaches 7.34." Additionally, the study revealed that as the latitude of a city increases, its overall electricity consumption decreases. Compared to the base system, the new system can reduce energy usage by an impressive 61.8% - 76.2%.

The analysis also demonstrated a clear correlation between a city's latitude and the system's emissions. Overall, adopting the novel system leads to a substantial reduction in carbon emissions, ranging from 51.3% to 63.3%. The researchers concluded, "Our new system outperforms the baseline system in terms of reducing discharge pressure. Notably, the higher the ambient temperature, the more significant the reduction in discharge pressure. At an ambient temperature of 40°C, the discharge pressure can be decreased by as much as 12.28%." This innovative PV-driven heating and cooling system holds great promise for revolutionizing energy consumption patterns in commercial supermarkets, offering a sustainable and efficient alternative to traditional systems.