To set up a platform for evaluating energy efficiency of water chiller and water source heat pump systems with EER or COP

the method of the second thermodynamic perfectibility was introduced. The range of thermodynamic perfectibility of room conditioners

water chillers and water-source heat pumps were calculated. The results show that the thermodynamic perfectibility of most water chillers is in the range of 0.3 to 0.5

the efficient products can reach 0.6

but the thermodynamic perfectibility of air to air products is about 0.2

and the thermodynamic perfectibility of air source heat pump water heaters is between water chillers and air to air products. The thermodynamic perfectibility is a useful index for the performance comparison of same or similar production in difference working conditions. The thermodynamic perfectibility analysis indicated that it characterizes the design and manufacturing level of products at present

and can be important foundation for the decision of minimum allowable performance

energy conservation performance and energy efficiency grade of energy efficiency standards for related products.