Preparing building cooling systems for a carbon-free future
Preparing building cooling systems for a carbon-free future lead image
Heat-driven refrigeration systems, which operate on waste heat rather than electricity, currently cost less compared to traditional refrigerators. However, as the world reduces its carbon emissions, so too does it reduce the waste heat from those emissions, making the operation of heat-driven refrigeration systems—which were originally suitable for many multistory buildings—more expensive.
Through simulations, Xu et al. proposed a new method of refrigeration, which partially couples an ejector and a compressor in a heat-driven refrigerator to significantly reduce the waste heat needed to generate the cooling effect. Based on their simulations, the authors showed the system increased efficiency by more than 20% compared to a traditional heat-driven refrigeration system.
To obtain their results, the team compared the thermodynamics and financial costs of their new system to a traditional one, and developed an advanced exergy model that included real, ideal, and mixed cycles to quantify how these improvements.
“Advanced exergy analysis also finds that the order of improvement potential is compressor, evaporator, condenser, and ejector, according to the sum of avoidable exergy destruction,” author Xi Shen said. “The sensitivity analysis of the ejector components’ efficiencies reveals that once the efficiencies of ejector components reach a certain point, the performance no longer improves.”
The authors plan to compare their simulations with experimental results.
“When establishing a real cycle, the efficiency of each component can be determined in conjunction with experiments to obtain more accurate information on component improvement,” Shen said.
Source: “Energy and advanced exergy analyses of novel ejector-compressor partially coupled refrigeration cycle for buildings with less solar energy,” by Yingjie Xu, Songlin Huang, Jiafeng Wang, Mengjie Song, Jiaqi Yu, and Xi Shen, Journal of Renewable and Sustainable Energy (2022). The article can be accessed at https://doi.org/10.1063/5.0102885 .
