Thermodynamic Optimization For Natural Gas Driven Vuilleumier Cycle Heat Pump

Due to the great heating consumption, the practical application of heat pump, an energy-efficient product, is significant for keeping sustainable development of energy and environment. Natural gas driven VM cycle heat pump works based on the theory of closed VM cycle using thermal as power with regenerators. In order to promote the comprehensive performance, the present article does optimization based on ideal, actual and quantum VM cycle, respectively.The COP of ideal VM cycle heat pump decreases as the warm temperature increases, and increases as the cold temperature and hot temperature increase, respectively. For a ideal VM cycle heat pump, the maximum hot active volume is larger than the maximum cold active volume, and the maximum molecules in hot chamber is more than the maximum molecules in cold chamber, so the influence of cold temperature on COP is the greatest among three heat sources. For a actual VM cycle heat pump, the COP is better with He than other work fluids. But the value of He is precious, and the refrigerant Ne has the similar operating characteristic, so we can choose He & Ne mix refrigerant instead in some occasion. The ESS calculating results show that 80% of the total heat losses is caused by regenerator losses and piston axial losses.For an endoreversible VM cycle heat pump, although the quantitative results are far more different with different conduction rule, the qualitative results are extraordinarily similar. At the point that heating rate gets max, the COP is not maximum. Analysis shows that as warm temperature increases the heating rate increases and the COP decreases. As the ratio of regenerator time to compress rate increases, the heating rate decreases and COP increases.For quantum VM cycle heat pump, when the amount of ladders on each constant temperature process and population of contiguous ladders is same, the COP gets highest. Based on the constant heat resources, the bigger frequency ratio is, the higher COP we get. Heat losses sharply decreases COP. the expression of similarity coefficient is presented under the condition that the regenerate time is ignored, and the finite-time thermodynamics optimization criterion of quantum VM cycle heat pump is deduced.