Simulation method of mixed refrigerant

Abstract

The invention discloses an analogue simulation method for mixed refrigerants, which comprises the following steps of: A, calculating thermophysical parameters, namely calculating the thermophysical parameters of the mixed refrigerants in different proportions on the basis of a phase equilibrium model and a Peng-Robinson state equation; b, typical proportion screening: screening a plurality of groups of mixed refrigerants with typical mixing proportions according to the thermophysical parameters calculated in the step A; and C, simulation verification is conducted, specifically, simulation verification is conducted on the multiple sets of typical mixing proportions through an air conditioner analogue simulation system, and corresponding circulating refrigerating capacity, circulating heating capacity and compressor power consumption parameters are obtained. The simulation model is established by utilizing a computer system, simulation verification is performed after typical mixing proportions are pre-screened, material object investment is not needed in the early stage, the cost is low, and the computer is short in operation period and simple to operate.

Description

Technical Field

[0001] The invention relates to the field of mixed refrigerants, and in particular to a simulation method for mixed refrigerants. Background Art

[0002] China's energy structure will undergo fundamental changes. For air-conditioning systems, it is urgent to find refrigerants with lower global warming potential (GWP). In the field of central air-conditioning in my country, there is a mature refrigerant system (R410A), and some companies are also trying to use R32 as a new central air-conditioning refrigerant, but because its GWP value is still as high as 676, it can only be used as a transitional product for central air-conditioning refrigerants. R290 refrigerant has become the first choice for future air-conditioning systems due to its superior environmental and thermodynamic properties. However, due to its flammability, related safety risks and charging capacity, the application of R290 refrigerant is limited to residential air-conditioning systems.

[0003] By precisely combining R290 and R32 in a specific ratio to create a new refrigerant mixture to replace the traditional R410A refrigerant, an effective solution is provided for the problems previously emphasized. However, the boiling points of refrigerants R32 and R290 are quite different, and they are typical non-azeotropic mixtures. After mixing, there will be a temperature glide problem caused by the boiling point. Therefore, the selection of the mixing ratio of refrigerants R32 and R290 has become an urgent problem for various manufacturers to solve.

[0004] The existing method is to prepare mixed refrigerants of different proportions in the laboratory and conduct simulation experiments on the mixed refrigerants of different proportions through the air-conditioning system. This method has a long cycle, cumbersome operation, and requires a lot of manpower and cost, and has certain limitations. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects in the background technology and provide a simulation method for mixed refrigerants. A simulation core is established by using a computer system, and simulation verification is performed after pre-screening a typical mixing ratio. No physical investment is required in the early stage, the cost is low, and the computer operation cycle is short and the operation is simple.

[0006] To achieve the above object, the present invention provides the following technical solution: a mixed refrigerant simulation method, comprising the following steps:

[0007] A. Calculation of thermophysical parameters: Calculation of thermophysical parameters of mixed refrigerants with different proportions based on the phase equilibrium model and the Peng-Robinson state equation;

[0008] B. Typical ratio screening: based on the thermophysical parameters calculated in step A, multiple groups of mixed refrigerants with typical mixing ratios are screened;

[0009] C. Simulation verification: Through the air conditioning simulation system, multiple groups of typical mixing ratios are simulated and verified to obtain the corresponding cycle cooling capacity, cycle heating capacity, and compressor power consumption parameters.

[0010] Preferably, the thermophysical property parameters in step A include critical pressure, critical temperature and latent heat of vaporization.

[0011] Preferably, the specific calculation process of step A is:

[0012] A1. Set the critical temperature T of single component R32 in the mixed refrigerant ci , critical pressure P ci , liquid phase molar coefficient x i , the critical temperature T of single component R290 cj , critical pressure P cj , liquid phase molar coefficient x j , binary mixed interaction coefficient k ij , step size 0.0001;

[0013] A2. Calculation formula based on single component synergistic attraction The formula for calculating the volume term Calculate the synergistic attraction term a of single component R32 and R290 respectively ci 、a cj and the covolume term b i , b j , where: R is the universal gas constant; its value is 8.314 J·mol-1·K-1, T c is the single component critical temperature; P c is the single component critical pressure;

[0014] A3. Set the initial pressure P and calculate the synergistic attraction term a of the liquid phase of the binary mixture according to the Peng-Robinson state equation: c1 , the co-volume term b1 and the liquid phase molar volume v are calculated as follows:

[0015]

[0016] Where: P is the given initial pressure, located at P ci With P cj between; ω is the eccentricity factor; T r is the relative temperature between the current temperature T and the critical temperature Tc, T r =T / Tc;

[0017] A4. Set the gas phase molar coefficient y of R32 and R290 i ,y j , calculate a of the gas phase of a binary mixture c2, the co-volume term b2 and the gas phase molar volume v', the calculation formula is as follows:

[0018]

[0019] A5. Use the phase equilibrium model to recalculate the gas phase molar coefficient y based on the liquid and gas phase molar volumes calculated in the above steps. i ', and with the set gas phase molar coefficient y i Compare; if they are not the same, update the given initial pressure P and repeat steps A3 to A5; if they are the same, continue with step A6;

[0020] A6. Determine sum(y i -1) is less than 0.0001, if not, update k ij , and repeat steps A3 to A6. If the requirements are met, output the binary mixed interaction coefficient k at this time ij ;

[0021] A7. According to the binary mixed interaction coefficient k ij , calculate the corresponding binary mixture thermophysical parameters, including critical pressure, critical temperature and latent heat of vaporization.

[0022] Preferably, in step C, the air conditioning simulation system is composed of a compressor module, a condenser module, a throttling module and an evaporator module connected to each other to form a refrigerant cycle model.

[0023] Preferably, the compressor module constructs a heat balance equation of the refrigeration compressor according to the heat balance relationship between the input power and the output power of the compressor:

[0024] Q case =P m -m com (h d -h s )

[0025] Where: Q case ——Heat exchange between compressor and surrounding environment (W); m com ——Mass flow rate (kg / s); h s ——Compressor inlet enthalpy (J / kg); h d ——Compressor outlet enthalpy (J / kg).

[0026] Preferably, the condenser module calculates the heat dissipation on the condenser refrigerant side and the heat exchange parameters on the air side by establishing an exchange model between the condenser and the heat sink environment, thereby obtaining the cycle cooling capacity. The specific model is as follows:

[0027] Heat dissipation on the refrigerant side:

[0028] Q c,ref=m c,ref (h c,in,ref -h c,out,ref )

[0029] Where: Q c,ref ——heat load of condenser (kw); m c,ref ——Mass flow rate of refrigerant (kg / s); h c,in,ref ——Refrigerant enthalpy at the condenser inlet (kJ / kg); h c,out,ref ——Refrigerant enthalpy at the condenser outlet (kJ / kg);

[0030] Air side heat exchange:

[0031] Q c,a =m c,a (h c,out,a -h c,in,a )

[0032] Where: Q c,a ——Heat exchange capacity on the air side of the condenser (kW); m c,a ——Mass flow rate of air (kg / s); h c,in,a ——Refrigerant enthalpy at the condenser inlet (kJ / kg); h c,out,a ——Refrigerant enthalpy at the condenser outlet (kJ / kg).

[0033] Preferably, the throttling module establishes a mathematical model of the throttling module of the refrigeration system based on the Bernoulli equation and the continuity equation:

[0034]

[0035] Where: m ref '——refrigerant flow rate through the thermal expansion valve (kg / s); A——flow area of ​​the thermal expansion valve; ρ ref ——Density of refrigerant at the inlet of thermal expansion valve (kg / m 3 ); P1——pressure at the inlet of thermal expansion valve (MPa); P2——pressure at the outlet of thermal expansion valve (MPa); C q ——Flow coefficient of thermal expansion valve,

[0036]

[0037] Preferably, the evaporator module calculates the heat absorption parameters of the evaporator refrigerant side and the heat exchange parameters of the air side by establishing an exchange model between the evaporator and the cold source environment and inputting the working parameters of the evaporator, specifically:

[0038] Heat absorption on the refrigerant side of the evaporator:

[0039] Q e,ref =mref (h e,ref,in -h e,ref,out )

[0040] Where: Q e,ref ——Heat exchange capacity of refrigerant in evaporator per unit time (kW); h e,ref,in ——Refrigerant enthalpy at the evaporator inlet (kJ / kg); h e,ref,out ——Refrigerant enthalpy at the evaporator outlet (kJ / kg);

[0041] Air side heat exchange:

[0042] Q e,a =m e,a (h e,a,in -h e,a,out )=m e,a εc p,a (t e,a,in -t e,a,out )

[0043] Where: Q e,a ——Heat exchange of air in the evaporator per unit time (kW); h e,a,in ——Air enthalpy at the evaporator inlet (kJ / kg); h e,a,out ——Air enthalpy at the evaporator outlet (kJ / kg); c p,a ——Specific heat capacity of air at constant pressure (kJ / kg·K); t e,a,in ——Air temperature at the evaporator inlet (K); t e,a,out ——Air temperature at the evaporator outlet (K); ε——Moisture separation coefficient.

[0044] Compared with the prior art, the simulation method of a mixed refrigerant disclosed in the present invention has the following beneficial effects:

[0045] (1) Aiming at the problem of calculating the thermophysical property parameters of the refrigerant R32 / R290 mixture, a thermophysical property calculation equation for the refrigerant R32 and R290 mixture considering temperature glide was constructed based on the phase equilibrium model and the Peng-Robinson state equation. The equation was used to calculate the thermophysical property parameters of the mixed refrigerant, thereby screening several typical groups of mixing ratios. Compared with the traditional ratio experiment, the mathematical model can effectively save a lot of manpower and time investment in the early stage of calculation, thus improving the screening efficiency and quality.

[0046] (2) By establishing a simulation model to simulate the refrigeration cycle process, the optimal mixing ratio is determined by comprehensively considering the unit cooling capacity and COP value. Then the main factors affecting the refrigeration cycle, namely, evaporation temperature, condensation temperature, subcooling and superheat, are adjusted to achieve the purpose of the optimal refrigeration cycle. Compared with the traditional physical air conditioning system cycle simulation, the simulation data acquisition is more intuitive, and the configuration parameters can be adjusted at any time, which is convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a flow chart of calculating the thermal physical property parameters in an embodiment of the present invention;

[0048] Figure 2 It is a framework diagram of the air conditioning simulation system in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] A mixed refrigerant simulation method disclosed in the present invention comprises the following steps:

[0051] A. Calculation of thermophysical parameters: Based on the phase equilibrium model and the Peng-Robinson state equation, the thermophysical parameters of mixed refrigerants with different proportions are calculated. The specific process is as follows: Figure 1 As shown, including:

[0052] A1. Set the critical temperature T of single component R32 in the mixed refrigerant ci , critical pressure P ci , liquid phase molar coefficient x i , the critical temperature T of single component R290 cj , critical pressure P cj , liquid phase molar coefficient x j , binary mixed interaction coefficient k ij , step size 0.0001;

[0053] A2. Calculation formula based on single component synergistic attraction The formula for calculating the volume term Calculate the synergistic attraction term a of single component R32 and R290 respectively ci 、a cj and the covolume term b i , b j , where: R is the universal gas constant, with a value of 8.314 J·mol-1·K-1, Tc is the single component critical temperature, P c is the single component critical pressure;

[0054] A3. Set the initial pressure P and calculate the synergistic attraction term a of the liquid phase of the binary mixture according to the Peng-Robinson state equation: c1 , the co-volume term b1 and the liquid phase molar volume v are calculated as follows:

[0055]

[0056] Where: P is the given initial pressure, located at P ci With P cj ω is the eccentricity factor; T r is the relative temperature between the current temperature T and the critical temperature Tc, T r =T / Tc;

[0057] A4. Set the gas phase molar coefficient y of R32 and R290 i、 y j , calculate a of the gas phase of a binary mixture c2 , the co-volume term b2 and the gas phase molar volume v', the calculation formula is as follows:

[0058]

[0059] A5. Use the phase equilibrium model to recalculate the gas phase molar coefficient y based on the liquid and gas phase molar volumes calculated in the above steps. i ', and with the set gas phase molar coefficient y i Compare; if they are not the same, update the given initial pressure P and repeat steps A3 to A5; if they are the same, continue with step A6;

[0060] A6. Determine sum(y i -1) is less than 0.0001, if not, update k ij , and repeat steps A3 to A6. If the requirements are met, output the binary mixed interaction coefficient k at this time ij ;

[0061] A7. According to the binary mixed interaction coefficient k ij , calculate the corresponding binary mixture thermophysical parameters, including critical pressure, critical temperature and latent heat of vaporization.

[0062] B. Typical ratio screening: based on the thermophysical parameters calculated in step A, multiple groups of mixed refrigerants with typical mixing ratios are screened;

[0063] C. Simulation verification: Through the air conditioning simulation system, multiple groups of typical mixing ratios are simulated and verified to obtain the corresponding cycle cooling capacity, cycle heating capacity, and compressor power consumption parameters.

[0064] The framework structure of the air conditioning simulation system is as follows: Figure 2 As shown, a simulation model of the entire cycle is formed by interconnecting a compressor module, a condenser module, a throttling module and an evaporator module.

[0065] Specifically, the compressor module establishes the parameters in the mathematical model according to the actual working conditions and data, mainly including the suction temperature, suction pressure, exhaust pressure, etc., calculates the exhaust temperature of the compressor, and obtains the suction enthalpy and exhaust enthalpy values. The theoretical specific work of the compressor during operation can be calculated using the enthalpy difference between suction and exhaust, which is:

[0066] In the compressor module simulation, only the compression and transport links are calculated. The calculated transport parameters mainly include: theoretical exhaust volume of the compressor, air delivery volume, mass flow rate, compressor inlet temperature and exhaust temperature. According to the thermal balance relationship between the input power and output power of the compressor, the thermal balance equation of the refrigeration compressor is constructed based on the above parameters:

[0067] Q case =P m -m com (h d -h s )

[0068] Where: Q case ——Heat exchange between compressor and surrounding environment (W); m com ——Mass flow rate (kg / s); h s ——Compressor inlet enthalpy (J / kg); h d ——Compressor outlet enthalpy (J / kg).

[0069] The key to the simulation of the condenser module is to describe the energy transfer and loss inside the condenser, establish the exchange model between the condenser and the heat sink environment, and obtain the results of the condenser simulation calculation by inputting the working parameters of the condenser, including the type of refrigerant, the structure and size of the condenser, the inlet and outlet states, etc., including the temperature distribution, pressure distribution, the heat dissipation on the refrigerant side of the condenser, the heat exchange parameters on the air side, and then obtain the parameters such as the cycle cooling capacity, and then evaluate the performance of the condenser and optimize the design. The specific calculation model is as follows:

[0070] Heat dissipation on the refrigerant side:

[0071] Q c,ref =m c,ref (h c,in,ref -h c,out,ref )

[0072] Where: Q c,ref ——heat load of condenser (kw); m c,ref——Mass flow rate of refrigerant (kg / s); h c,in,ref ——Refrigerant enthalpy at the condenser inlet (kJ / kg); h c,out,ref ——Refrigerant enthalpy at the condenser outlet (kJ / kg).

[0073] Air side heat exchange:

[0074] Q c,a =m c,a (h c,out,a -h c,in,a )

[0075] Where: Q c,a ——Heat exchange capacity on the air side of the condenser (kW); m c,a ——Mass flow rate of air (kg / s); h c,in,a ——Refrigerant enthalpy at the condenser inlet (kJ / kg); h c,out,a ——Refrigerant enthalpy at the condenser outlet (kJ / kg).

[0076] The specific heat of air is a constant, and the enthalpy of air is:

[0077] Δh=c p,a (T out -T in )

[0078] Where: Δh——change in air enthalpy (kJ / kg); c p,a ——Specific heat capacity of air (kJ / k·kg); T in ——Condenser inlet air temperature (K); T out ——Condenser inlet air temperature (K).

[0079] The movement of the refrigeration system in the throttling module is mainly manifested as a drop in pressure and a change in flow rate. Based on the Bernoulli equation and the continuity equation, a mathematical model of the throttling device of the refrigeration system is established. By calculating parameters such as flow, pressure, and flow rate, the movement and changes of the fluid inside the throttle valve are described. The key to establishing a mathematical model of the throttle valve is to calculate the mass flow rate of the refrigerant in the throttle valve. The mass flow rate of the refrigerant in the throttle valve can be expressed by the following formula:

[0080]

[0081] Where: m ref '——refrigerant flow rate through the thermal expansion valve (kg / s); A——flow area of ​​the thermal expansion valve; ρ ref ——Density of refrigerant at the inlet of thermal expansion valve (kg / m 3); P1——pressure at the inlet of thermal expansion valve (MPa); P2——pressure at the outlet of thermal expansion valve (MPa); C q ——Flow coefficient of thermal expansion valve

[0082]

[0083] The flow rate before and after the thermal expansion valve remains unchanged, and the throttling process is rapid. The throttling can be regarded as an adiabatic process, with no heat exchange with the outside world, so the enthalpy values ​​before and after throttling are equal, that is:

[0084] h v,in =h v,out

[0085] Where: h v,in ——Enthalpy of refrigerant at the inlet of thermal expansion valve (kJ / kg); h v,out ——Enthalpy of refrigerant at the outlet of thermal expansion valve (kJ / kg).

[0086] The key to evaporator module simulation is to describe the energy transfer and loss inside the evaporator, establish an exchange model between the evaporator and the cold source environment, and obtain the results of evaporator simulation calculations by inputting the working parameters of the evaporator, including the type of refrigerant, evaporator structure and size, inlet and outlet states, etc., including temperature distribution, pressure distribution, evaporator refrigerant side heat absorption, air side heat exchange and other parameters, and then evaluate the performance of the evaporator and optimize the design.

[0087] Heat absorption on the refrigerant side of the evaporator:

[0088] Q e,ref =m ref (h e,ref,in -h e,ref,out )

[0089] Where: Q e,ref ——Heat exchange capacity of refrigerant in evaporator per unit time (kW); h e,ref,in ——Refrigerant enthalpy at the evaporator inlet (kJ / kg); h e,ref,out ——Refrigerant enthalpy at the evaporator outlet (kJ / kg).

[0090] When the air is cooled in the evaporator, the temperature and humidity change accordingly. At this time, the heat exchange on the air side is:

[0091] Q e,a =m e,a (h e,a,in -h e,a,out )=m e,a εc p,a (t e,a,in -t e,a,out )

[0092] Where: Q e,a ——Heat exchange of air in the evaporator per unit time (kW); h e,a,in ——Air enthalpy at the evaporator inlet (kJ / kg); h e,a,out ——Air enthalpy at the evaporator outlet (kJ / kg); c p,a ——Specific heat capacity of air at constant pressure (kJ / kg·K); t e,a,in ——Air temperature at the evaporator inlet (K); t e,a,out ——Air temperature at the evaporator outlet (K); ε——Moisture separation coefficient, a physical quantity that describes the rate at which a material absorbs or releases moisture when the relative humidity changes. It refers to the ratio of the amount of moisture adsorbed or released by a material per unit area per unit time to the surface area of ​​the material per unit area per unit time.

[0093] The cycle simulation model is used to simulate the energy consumption and environmental performance of mixed refrigerants with different ratios in central air conditioning, and output a series of parameters such as compressor power consumption, cycle cooling capacity, cycle heating capacity, COP and exhaust temperature, which are compared with the simulation parameters of traditional R410a to ensure that the new refrigerant has better environmental performance than R410a while ensuring the refrigeration effect, and better optimize the current production and living conditions of human beings. At the same time, the simulation model can be used to further verify and screen the mixing ratio of R32 and R290.

[0094] As a substitute for the current central air conditioning refrigerant R410a, the R32 / R290 mixed refrigerant has good environmental protection, its ozone depletion potential (ODP) is 0, and its global warming potential is between 20-676, which is significantly improved compared with R410a. In addition, according to the simulation results, when using mixed refrigerants, higher refrigeration performance and lower energy consumption can be provided.

[0095] The simulation is carried out synchronously with the 1:1 mixed R32 / R290 mixed refrigerant and the traditional refrigerant R410a. The performance parameter structure is shown in Table 1. According to Table 1, it can be seen that the 1:1 mixed R32 / R290 mixed refrigerant has better refrigeration effect and energy consumption performance than the traditional refrigerant R410a. This is because R32 and R290 have higher refrigeration performance and lower environmental impact respectively. Mixing them can give full play to their advantages and make up for their respective shortcomings.

[0096] Table 1 Simulation comparison table

[0097] substance R32 / R290 R410a difference Cycle cooling capacity (kW) 1.1892 1.2027 0.011 Circulation heating capacity (kW) 2.1486 2.1437 0.0023 Compressor power consumption (kW) 0.6899 0.7098 0.028 COP 1.72 1.69 0.018 Exhaust temperature(K) 331.5 337.9 0.019 Exhaust pressure(kPa) 2669.5 2972.2 0.102

[0098] Finally, it should be noted that the above embodiments are only preferred embodiments of the present invention and are not limitations on the technical solutions of the present invention. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present invention.

Claims

1. A simulation method for mixed refrigerant, characterized in that The steps include: A. Calculation of thermophysical parameters: Calculation of thermophysical parameters of mixed refrigerants with different proportions based on the phase equilibrium model and the Peng-Robinson state equation; B. Typical ratio screening: based on the thermophysical parameters calculated in step A, multiple groups of mixed refrigerants with typical mixing ratios are screened; C. Simulation verification: Through the air conditioning simulation system, multiple groups of typical mixing ratios are simulated and verified to obtain the corresponding cycle cooling capacity, cycle heating capacity, and compressor power consumption parameters.

2. The simulation method of a mixed refrigerant according to claim 1, characterized in that: The thermophysical property parameters in step A include critical pressure, critical temperature and latent heat of vaporization.

3. The simulation method of a mixed refrigerant according to claim 2, characterized in that: The specific calculation process of step A is: A1. Set the critical temperature T of single component R32 in the mixed refrigerant ci , critical pressure P ci , liquid phase molar coefficient x i , the critical temperature T of single component R290 cj , critical pressure P cj , liquid phase molar coefficient x j , binary mixed interaction coefficient k ij , step size 0.0001; A2. Calculation formula based on single component synergistic attraction The formula for calculating the volume term Calculate the synergistic attraction term a of single component R32 and R290 respectively ci 、a cj and the covolume term b i 、b j , where: R is the universal gas constant; its value is 8.314 J·mol-1·K-1, T c is the single component critical temperature; P c is the single component critical pressure; A3. Set the initial pressure P and calculate the synergistic attraction term a of the liquid phase of the binary mixture according to the Peng-Robinson state equation: c1 , the co-volume term b1 and the liquid phase molar volume v are calculated as follows: a c1 =∑ i ∑ j x i x j a ij ; b1=∑ i ∑ j x i x j b ij ; Where: P is the given initial pressure, located at P ci With P cj between; ω is the eccentricity factor; T r is the relative temperature between the current temperature T and the critical temperature Tc, T r =T / Tc; A4. Set the gas phase molar coefficient y of R32 and R290 i、 y j , calculate a of the gas phase of a binary mixture c2 , the co-volume term b2 and the gas phase molar volume v', the calculation formula is as follows: to c2 =∑ i ∑ j and i and j to ij ; b2=∑ i ∑ j y i y j b ij ; A5. Use the phase equilibrium model to recalculate the gas phase molar coefficient y based on the liquid and gas phase molar volumes calculated in the above steps. i ', and with the set gas phase molar coefficient y i Compare; if they are not the same, update the given initial pressure P and repeat steps A3 to A5; if they are the same, continue with step A6; A6. Determine sum(y i -1) is less than 0.0001, if not, update k ij , and repeat steps A3 to A6. If the requirements are met, output the binary mixed interaction coefficient k at this time ij ; A7. According to the binary mixed interaction coefficient k ij , calculate the corresponding binary mixture thermophysical parameters, including critical pressure, critical temperature and latent heat of vaporization.

4. The simulation method of a mixed refrigerant according to claim 1, characterized in that: In the step C, the air conditioning simulation system is composed of a compressor module, a condenser module, a throttling module and an evaporator module connected to each other to form a refrigerant cycle model.

5. The simulation method of a mixed refrigerant according to claim 4, characterized in that: The compressor module constructs a heat balance equation for the refrigeration compressor based on the heat balance relationship between the input power and output power of the compressor: Q case =P m -m com (h d -h s ) Where: Q case ——Heat exchange between compressor and surrounding environment (W); m com ——Mass flow rate (kg / s); h s ——Compressor inlet enthalpy (J / kg); h d ——Compressor outlet enthalpy (J / kg).

6. The simulation method of a mixed refrigerant according to claim 4, characterized in that: The condenser module establishes an exchange model between the condenser and the heat sink environment, calculates the heat dissipation on the condenser refrigerant side and the heat exchange parameters on the air side, and then obtains the cycle cooling capacity. The specific model is as follows: Heat dissipation on the refrigerant side: Q c,ref =m c,ref (h c,in,ref -h c,out,ref ) Where: Q c,ref ——heat load of condenser (kw); m c,ref ——Mass flow rate of refrigerant (kg / s); h c,in,ref ——Refrigerant enthalpy at the condenser inlet (kJ / kg); h c,out,ref ——Refrigerant enthalpy at the condenser outlet (kJ / kg); Air side heat exchange: Q c,a =m c,a (h c,out,a -h c,in,a ) Where: Q c,a ——Heat exchange capacity on the air side of the condenser (kW); m c,a ——Mass flow rate of air (kg / s); h c,in,a ——Refrigerant enthalpy at the condenser inlet (kJ / kg); h c,out,a ——Refrigerant enthalpy at the condenser outlet (kJ / kg).

7. The simulation method of a mixed refrigerant according to claim 4, characterized in that: The throttling module establishes a mathematical model of the throttling module of the refrigeration system based on the Bernoulli equation and the continuity equation: Where: m ref '——refrigerant flow rate through the thermal expansion valve (kg / s); A——flow area of ​​the thermal expansion valve; ρ ref ——Density of refrigerant at the inlet of thermal expansion valve (kg / m 3 ); P1——pressure at the inlet of thermal expansion valve (MPa); P2——pressure at the outlet of thermal expansion valve (MPa); C q ——Flow coefficient of thermal expansion valve, 8. The simulation method of a mixed refrigerant according to claim 4, characterized in that: The evaporator module calculates the heat absorption parameters of the evaporator refrigerant side and the heat exchange parameters of the air side by establishing an exchange model between the evaporator and the cold source environment and inputting the working parameters of the evaporator, specifically: Heat absorption on the refrigerant side of the evaporator: Q e,ref =m ref (h e,ref,in -h e,ref,out ) Where: Q e,ref ——Heat exchange capacity of refrigerant in evaporator per unit time (kW); h e,ref,in ——Refrigerant enthalpy at the evaporator inlet (kJ / kg); h e,ref,out ——Refrigerant enthalpy at the evaporator outlet (kJ / kg); Air side heat exchange: Q e,a =m e,a (h e,a,in -h e,a,out )=m e,a εc p,a (t e,a,in -t e,a,out ) Where: Q e,a ——Heat exchange of air in the evaporator per unit time (kW); h e,a,in ——Air enthalpy at the evaporator inlet (kJ / kg); h e,a,out ——Air enthalpy at the evaporator outlet (kJ / kg); c p,a ——Specific heat capacity of air at constant pressure (kJ / kg·K); t e,a,in ——Air temperature at the evaporator inlet (K); t e,a,out ——Air temperature at the evaporator outlet (K); ε——Moisture separation coefficient.

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