Thermodynamic analysis of hydrate-based refrigeration cycle
Journal
Energy
Journal Volume
220
Date Issued
2021
Author(s)
Abstract
Clathrate hydrates (hydrates) have a larger dissociation heat than an evaporation heat of the working fluid of conventional refrigeration systems. This property can be applied to a novel refrigeration system. In this study, theoretical performance analysis of the refrigeration system utilizing hydrates as its working medium was conducted. We modeled the thermodynamic cycle of the hydrate-based refrigeration system composed of following processes: adiabatic compression, hydrate formation at high temperature, adiabatic expansion, and hydrate dissociation at low temperature. Based on the thermodynamic cycle, the coefficient of performance (COP) of the hydrate cycle was theoretically formulated with thermodynamic state functions of the working medium. Using the formula, COP was calculated on the three hydrate forming systems including HFC-32 + cyclopentane (CP) + water, Kr + CP + water, and HFC-41 + CP + water. The analysis based on the calculated results revealed that the dissociation heat of hydrates and the enthalpy change of guest gas were dominant factors to COP and polyatomic molecules would be appropriate for guest gas of hydrates. The maximum COP values on the hydrate cycle were comparable to those of the reversed Rankine cycle. The hydrate-based refrigeration system outperformed conventional refrigeration systems in terms of safety and environmental-friendliness. ? 2020 Elsevier Ltd
Subjects
Dissociation; Gas hydrates; Hydration; Rankine cycle; Temperature; Thermoanalysis; Adiabatic compression; Coefficient of performances (COP); Environmental friendliness; Polyatomic molecules; Refrigeration cycles; Refrigeration system; Theoretical performance; Thermo dynamic analysis; Refrigeration; compression; cooling; enthalpy; evaporation; performance assessment; thermodynamics
SDGs
Type
journal article