A cold storage air conditioning system with energy-efficient supercooled water ice slurry generation by using heat recovery and regeneration

Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Department of Building Science, School of Architecture, Tsinghua University, Beijing, 100084, China

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Abstract

Ice slurry cold storage technology using supercooled water is considered one of the most efficient methods. In traditional systems, to prevent ice crystal blockage in the supercooled water exchanger, the water from ice tank is typically heated to 0.5°C to melt ice crystals , resulting in a 15%–20 % cooling loss and a potential blockage risk. Although heat regeneration method has been introduced to mitigate cooling loss, the internal heat-cold offset still limits system efficiency. In this study, a novel system integrating both heat recovery and heat regeneration is proposed to improve system efficiency. In the system, return chilled water is used to melt ice crystals, enabling cooling energy recovery and eliminating the heat-cold offset, while the regeneration exchanger is used to decrease the inlet temperature of the supercooled water exchanger, reducing the cooling loss. A mathematical model of the whole system is developed and the system performance under rated operating condition is analyzed. The results indicate the proposed system enhances ice-crystal melting, increases the effective utilization of cooling capacity by 7.14 %, and improves the ice-making COP by 6.1% compared with the traditional system, and increases the system COP by 18.3% and 12.2% compared with the traditional and regeneration systems, respectively.