The introduction (exergy), as a parameter to evaluate energy value, stipulates the "value" of energy from both "quantity" and "quality" and solves the problem that there is no parameter in the thermodynamics for a long time to evaluate the energy value alone Has changed people's traditional viewpoints on the nature of energy, the loss of energy and the conversion efficiency that can be achieved, and provides the scientific basis for thermal analysis. At the same time, it also profoundly reveals the essence of deterioration and degeneration of energy in the process of conversion, indicating the direction for rational use of energy. The function of a heat pump is to draw heat from the environment and pass it on to a heated object (a hot object). At present, foreign heat pump technology has been widely used, and is still growing. With the national emphasis on energy conservation and environmental protection, the development and promotion of heat pumps in our country have also been rapidly developed. In our field of HVAC, heat pumps, especially compression heat pump has a very wide range of applications. In this paper, the exergy analysis is applied to the application of compression heat pump in heating system. Exergy and Energy For a long time, people were accustomed to measuring the value of energy from the amount of energy, regardless of what energy it consumed. As we all know, different forms of energy, the value of their power use is not the same. Even in the same form of energy, under different conditions also have different abilities. Although "enthalpy" and "internal energy" have the meaning and dimension of "energy", they do not reflect the quality of energy. However, "entropy" is closely related to the "quality" of energy, but it can not reflect the "quantity" of energy and there is no direct "quality" of energy. In order to be able to use it economically, it is necessary to adopt the same measure that reflects both the quantity and the "qualitative" differences between the various energies. Exergy is just such a thermodynamic physical quantity that scientifically evaluates the value of energy. 1.1 The concept of exergy and fire The energy of all forms is not the same as the ability to switch to advanced energy. If you use this conversion capacity as a yardstick, you can evaluate the pros and cons of various forms of energy. However, the size of the conversion capacity is related to the environmental conditions and is also related to the degree of irreversibility of the conversion process. Therefore, in fact, under the given environmental conditions, the theoretically maximum conversion capacity can be used as a measure of energy taste, which is called Exergy. It is defined as follows: When the system reversibly changes from an arbitrary state to a state that is in balance with a given environment, it can theoretically be infinitely converted into energy of any other form of energy, which is called exergy [1] . Since the most complete conversion is possible only in the reversible process, it can be assumed that (exergy) is the minimum useful work or theoretically minimum useful work theoretically done in a reversible process under given environmental conditions. Correspondingly, everything that can not be converted to exergy is called Anergy. Any energy E consists of two parts, Ex and A, ie E = Ex + An 1.2 Energy Conversion Rules From the viewpoints of exergy and fire, energy The conversion law can be summarized as follows: (1) (exergy) and (fire) the total amount of conservation, that is, we often say that the principle of conservation of energy. (2) (fire no) can no longer be converted to (exergy), otherwise it will violate the second law of thermodynamics. (3) reversible process does not appear devalued deterioration, so the (exergy) the total conservation. (4) In all practical irreversible processes, inevitable devaluations can occur. Exergy will be partially "degenerated" into "extinction" and become exergy losses. Because this kind of degradation can not be compensated, the exergy loss is the real loss in energy conversion. (5) The exergy value of isolated systems does not increase, but only decreases, at most, the same, that is, the exergy reduction principle of the isolated system. So (exergy), like entropy, can be used as a criterion for the natural process directionality. 1.3 Heat (Exergy) If the temperature of a system is higher than the ambient temperature, when the system reversibly changes from any state to a state that is in balance with the state of the environment (aka "dead state"), the heat Q is released, The outside world to make the greatest usefulness. This maximum useful work is called ExQ heat. If the heat Q is obtained from a constant temperature heat source whose thermodynamic temperature is T, the maximum work Wmax that can be obtained from the heat when the ambient temperature is T0 is the heat ExQ is heat (exergy) having the following properties: (1) heat (Exergy) is the maximum amount of useful work that can be converted by the system's heat. (2) The amount of heat (exergy) is not only related to the size of Q, but also to the system temperature T and the ambient temperature T0. (3) The same quantity of Q, with different heat (exergy) at different temperatures T, the higher the T is, the greater the exergy is when the ambient temperature is determined. (4) Heat (exergy) is the same amount of process as heat, not state quantity. Exergy balance and exergy analysis When we analyze the energy of a thermal system, we hope to find out the parts and causes of the loss through the analysis of the process of energy morphological changes, the quantitative calculation of the effective use of energy and the loss In order to propose improvements and forecast the improved results. We usually use the energy balance analysis is divided into heat balance (enthalpy balance) analysis and (exergy) balance analysis of two. 2.1 (Exergy) balance and (exergy) loss of energy conservation is a common law, the energy balance of payments should be maintained. However, exergy is only an available part of energy, and its income and expenditure are generally unbalanced. During the actual conversion process, some of the available energy can be converted into unusable energy and the exergy will be reduced, which is called Exergy loss. This does not violate the law of conservation of energy. Exergy balance is the sum of (exergy) and exergy loss (unavailability energy). Supposing that the input exergy across the system boundary is Exin, the exergy output is Exout, the system exergy loss is Ii and the external work is W, then their equilibrium relationship is ΣExin + W = Σ Exout + ΣIi (Exergy) balance not only considers the amount of energy, but also take into account the quality of energy. In considering the exergy balance, the key is the need to write down the exergy losses in order to maintain balance. Among them, the internal irreversible (exergy) loss term is not reflected in the heat balance. Therefore, there is a qualitative difference between the two methods of analysis. However, there is an intrinsic link between the two and the exergy balance is based on heat balance. 2.2 Exergy Analysis and Exergy Efficiency The usual caloric balance and energy conversion efficiency do not reflect the degree of exergy utilization, so we introduced the concept of exergy efficiency. Exergy efficiency and energy conversion efficiency are defined similarly, except that exergy efficiency is the ratio of earnings (exergy) to payments (exergy). With the concept of exergy efficiency, we can set up an exergy balance for a given thermal system and perform exergy analysis of it to achieve the following objectives: (1) Quantitatively calculate energy (fire Use) of the various income and expenditure, utilization and loss situation. Revenue and expenditure balance is the basis, the flow of energy to include revenue items and a variety of loss items, according to the proportion of the distribution can be divided primary and secondary. (2) Through the calculation of efficiency, to determine the effect of energy conversion and the degree of effective use. (3) Analysis of energy use