Rapid calculation method for transient refrigerating and heating of shelter

Abstract

The invention belongs to the technical field of shelter temperature control, and particularly relates to a rapid calculation method for transient refrigerating and heating of a shelter. According to the technical scheme, the rapid calculation method for transient refrigeration and heating of the shelter comprises the following steps that S1, a first-order transient differential heat exchange equation is established; s2, introducing average thermophysical parameters of equipment, and establishing a high-order differential transient heat exchange equation; and S3, carrying out order reduction processing and matlab solving on the high-order differential equation. The invention provides a rapid calculation method for transient refrigerating and heating of a shelter, which is used for carrying out numerical calculation aiming at the index requirement of reaching a target temperature value within a specified time in the index requirements of the shelter. Influences of air conditioner power, cabin wall heat insulation performance, cabin equipment, air heat absorption and release and the like on the cabin temperature on the time scale are comprehensively considered, the cabin temperature is visually displayed along with time changes, and iterative optimization calculation of transient changes of the cabin temperature can be rapidly carried out.

Description

Technical Field

[0001] The invention belongs to the technical field of cabin temperature control, and in particular relates to a method for quickly calculating transient cooling and heating of a cabin. Background Art

[0002] As a mobile, temperature-controlled work space product, the shelter is widely used in the military, medical, emergency communications, industrial control and other fields. Especially in the field of military command and medical rescue, it can be deployed in extreme high and low temperature environments because of its strong thermal insulation and constant temperature control capabilities. In addition to its own total heat transfer coefficient and constant temperature requirements under extreme temperature conditions, the shelter also stipulates the temperature requirements for heating and cooling and the cut-off time under extreme temperature conditions, in order to meet the requirements of reaching the comfort temperature of the cabin personnel or the normal startup and operation temperature of the equipment within the specified time under extreme temperature conditions.

[0003] At present, the key links of cabin temperature design (air conditioning selection and insulation layer design) mainly rely on the numerical accumulation calculation of power consumption under steady state and general fluid calculation software. However, the numerical calculation of power consumption only considers steady-state conditions, and does not consider the temperature rise and fall time; when dealing with the temperature control problem of the square cabin with air conditioning temperature control characteristics, the commonly used fluid calculation software has the problem of incomplete consideration of factors, complex modeling, and long calculation time, resulting in the problem of excessively high optimization iteration cost. For example, icepak cannot perform heat dissipation simulation under the air conditioning power limit, the air conditioning environment calculation module of 6sigma Room cannot perform transient simulation, and the modeling and transient calculation time cost of cradle, starCCM+, etc. is too high. The above methods cannot fully consider the impact of transient temperature change index requirements on the design, or cannot perform rapid iterative calculation optimization of the incidental air conditioning characteristics and bulkhead insulation characteristics in the transient calculation of square cabin temperature control.

[0004] Therefore, it is necessary to establish a fast numerical calculation method with the temperature control characteristics of the cabin, so as to realize the design of the cabin's thermal insulation parameters, the selection of air conditioners, and the reasonable configuration of the equipment in the cabin. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide a rapid calculation method for transient cooling and heating of a cabin, and to carry out numerical calculation for the "index requirement of reaching the target temperature value within the specified time" in the cabin index requirement. In the temperature control design, the influence of air conditioning power, cabin wall insulation performance, cabin equipment, air absorption and heat release, etc. on the cabin temperature on a time scale is comprehensively considered, so as to realize an intuitive display of the cabin temperature changes over time, and to quickly perform iterative optimization calculations of transient changes in cabin temperature.

[0006] The technical solution adopted by the present invention is:

[0007] The method for rapid calculation of transient cooling and heating of shelters includes the following steps:

[0008] S1: Establish the first-order transient differential heat transfer equation:

[0009] S11: Transient heat transfer balance equation based on energy flow;

[0010] S12: Calculate the total heat transfer coefficient of the cabin;

[0011] S13: Calculation of logarithmic mean temperature difference of air conditioning heat exchange;

[0012] S14: The total heat transfer differential equation is established;

[0013] S2: Introduce the average thermal physical property parameters of the equipment and establish a high-order differential transient heat transfer equation:

[0014] S21: Calculate the average specific heat capacity of the device;

[0015] S22: Construct transient heat balance equation of equipment;

[0016] S23: Establish a transient heat balance equation including the heat transfer characteristics of air conditioners, shelters, and equipment;

[0017] S3: Reduction of high-order differential equations and solution with Matlab:

[0018] S31: Equation decomposition and reduction;

[0019] S32: Use the Runge-Kutta algorithm of MATLAB to quickly solve.

[0020] The present invention solves the problem of transient temperature rise and fall evaluation and rapid transient numerical calculation in the temperature control design of the shelter with the characteristics of the shelter. Numerical calculation is carried out for the "index requirement of reaching the target temperature value within the specified time" in the shelter index requirement. In the temperature control design, the present invention comprehensively considers the influence of air conditioning power, cabin wall insulation performance, cabin equipment, air absorption and release of heat, etc. on the cabin temperature on a time scale. The present invention realizes an intuitive display of the cabin temperature changing over time, and can quickly perform iterative optimization calculations of transient changes in cabin temperature.

[0021] The present invention establishes a transient temperature field state equation with the temperature control characteristics of the shelter, and solves the problem of quantitatively calculating the temperature change on a time scale when the shelter is heated or cooled.

[0022] The present invention introduces the average thermophysical parameters of the equipment in the cabin and constructs a high-order differential equation including the equipment, air conditioning, cabin, and cabin air, which improves the accuracy of transient calculation and expands the scope of application under the condition that the influence of the equipment cannot be ignored.

[0023] The present invention disassembles high-order differential equations, uses MATLAB programming to solve the temperature field state equation of the cabin temperature control system and draws the temperature rise and fall process curves, and solves the intuitive description of the temperature change curve over time under a specific given power.

[0024] As a preferred solution of the present invention, step S11 is specifically as follows:

[0025] According to the transient heat exchange characteristics of the shelter, considering the power output of air conditioning cooling or heating in the cabin, the heat absorption of the air in the cabin, and the heat exchange between the shelter and the external environment, the transient micro-period balance equation is established as follows:

[0026] P rg =P kx +P jh (1-1);

[0027]

[0028] Among them, P rg is the air conditioner output power, P kx P is the heat absorption or heat release power of the air in the cabin, jh is the power loss of heat exchange between the cabin outer wall and the cabin environment, c k is the specific heat capacity of air, m k is the cabin air quality, T k is the average temperature of the air in the cabin, t is the time, K gx Total heat transfer coefficient of cabin, S x is the heat exchange area of ​​the cabin, ΔT jh is the average heat exchange temperature difference between the inside and outside of the cabin.

[0029] As a preferred solution of the present invention, step S12 is specifically as follows:

[0030] When similar box materials and thicknesses are used and actual measurements can be performed, the total heat transfer coefficient value is obtained by actual measurement; when the conditions for measuring the heat transfer coefficient are not met, the local heat transfer coefficient of the bulkhead is calculated first, and then the total heat transfer coefficient of the bulkhead is calculated according to formula (1-3) and formula (1-4);

[0031]

[0032] Among them, K j : is the local heat transfer coefficient within the area of ​​the jth bulkhead of the cabin, in units of W / (m 2 K);

[0033] α N :Heat transfer coefficient inside the cabin, unit: W / (m 2 K);

[0034] δ l: The thickness of the i-th layer of the j-th bulkhead in the cabin insulation wall, in m;

[0035] λ i : Thermal conductivity of the i-th layer of the j-th bulkhead in the thermal insulation wall of the cabin, unit: W / (m·K);

[0036] α w : Heat transfer coefficient outside the cabin, unit: W / (m 2 K);

[0037] The total heat transfer coefficient of the bulkhead is calculated by averaging the area ratios of different materials and structures.

[0038]

[0039] Among them, K gx : is the total heat transfer coefficient of the cabin, unit is W / (m 2 K);

[0040] K j : is the local heat transfer coefficient within the area of ​​the jth bulkhead of the cabin, in units of W / (m 2 K);

[0041] S j : is the area of ​​the jth bulkhead, in m 2 .

[0042] As a preferred solution of the present invention, step S13 is specifically as follows:

[0043] In the heat exchange process between the cabin and the outside environment, since the outside environment can be regarded as an isothermal heat sink, and in the process of heating or cooling the cabin by air conditioning, the temperature difference between the outlet air temperature and the return air temperature is large, the logarithmic mean temperature difference is used as the average heat exchange temperature difference of the cabin. The temperature difference calculation formula (1-5) is as follows:

[0044]

[0045] Where, ΔT jh is the average heat exchange temperature difference between the inside and outside of the cabin, in °C;

[0046] T kh is the air supply temperature of the air conditioner, in °C;

[0047] T kr is the return air temperature of the air conditioner, in °C;

[0048] T w is the stable temperature of the external environment, in °C;

[0049] The supply and return air temperatures of the air conditioner are related to the output power and air volume of the air conditioner, and are characteristic parameters of the air conditioner. The average temperature in the cabin is T k, which can be approximated by the air supply temperature T kh and return air temperature T kr The arithmetic mean is substituted, and the relationship between the average heat exchange temperature difference of the cabin and the average temperature in the cabin is finally established as follows:

[0050]

[0051] Among them, V k Air supply volume of air conditioner, unit: m 3 / s;

[0052] ρ k is the air density, in kg / m 3 .

[0053] As a preferred solution of the present invention, step S14 is specifically as follows:

[0054] After combining formula (1-2) and formula (1-6), the transient differential equation for heat transfer in the shelter (1-7) is obtained as follows:

[0055]

[0056] As a preferred solution of the present invention, step S21 is specifically as follows:

[0057] When there are many devices placed in the cabin, the absorption or release of heat by the equipment has a significant impact on the heating or cooling time. The volume and weight of the placed equipment can be known, and the overall average specific heat capacity c of the equipment can be calculated based on the mass specific gravity of the equipment material. s , as shown in formula (2-1):

[0058]

[0059] Among them, c j is the specific heat capacity of material j, in J / (kg.k);

[0060] m j is the mass of material j, in kg.

[0061] As a preferred solution of the present invention, step S22 is specifically as follows:

[0062] The transient heat absorption or release of the equipment is regarded as the change in the internal energy of the equipment, and equation (2-2) is established as follows:

[0063]

[0064] Among them, c s is the average specific heat capacity of the equipment, in J / (kg.k);

[0065] m s is the equipment mass, in kg;

[0066] K k is the cabin air heat transfer coefficient, unit: W / (m 2 K);

[0067] S s is the heat exchange area of ​​the equipment, in m 2 ;

[0068] T ks The temperature of the air near the equipment, in °C;

[0069] T s is the average temperature of the equipment, in °C.

[0070] As a preferred solution of the present invention, step S23 is specifically as follows:

[0071] Since the space inside the shelter is generally relatively small, the local temperature gradient is ignored and the temperature T of the air close to the equipment is approximated. ks The average temperature in the cabin T k Equivalently, transform formula (2-2) into formula (2-3):

[0072]

[0073] Substituting formula (2-3) into formula (1-7) to establish the transient second-order differential equation group considering the influence of the equipment in the cabin on the temperature of the other cabin is as follows:

[0074]

[0075] Among them, α is the equipment heat absorption influence coefficient, and β is the air conditioning performance influence coefficient, which can be calculated according to formula (2-5) and formula (2-6).

[0076] As a preferred solution of the present invention, step S31 is specifically as follows:

[0077] In order to solve the high-order differential equation, the differential equation of formula (2-4) is decomposed into a multivariate low-order differential equation group, and the Runge-Kutta algorithm is used in MATLAB software to quickly solve it. The decomposed equation group is as follows:

[0078]

[0079] Among them, y1' and y2' are the elements to be solved for the two-variable differential equation system;

[0080] T s The initial condition is the ambient temperature;

[0081] The initial condition is 0;

[0082] The air conditioner output power is preliminarily set within the selected range, and based on the specified heating and cooling time, the temperature change value is calculated and the temperature change curve is drawn.

[0083] As a preferred solution of the present invention, step S32 is specifically as follows:

[0084] By using the first-order differential equation solution method in MATLAB software, the differential equation can be quickly solved to obtain the functional relationship between the equipment temperature and time, and then the formula (2-3) can be used to obtain the curve of the internal temperature of the cabin changing with time; using this temperature change curve, combined with the given power of the air conditioner, the functional relationship between the air conditioner, the cabin temperature, and the given time can be quickly constructed, and the genetic algorithm toolbox in MATLAB software can be used to achieve rapid numerical iterative optimization.

[0085] The beneficial effects of the present invention are:

[0086] 1. The present invention constructs a cooling and heating transient temperature field state algorithm under the temperature control characteristics of the cabin air conditioner, and more accurate air conditioner selection and temperature setting calculation.

[0087] 2. The present invention can quickly and quantitatively calculate the temperature rise time curve under given external power conditions in the early stage of the design of the cabin temperature control system, which is convenient for comparing transient temperature control indicators.

[0088] 3. Based on conventional transient calculations, the present invention introduces the average thermal physical parameters of equipment and personnel, constructs a high-order differential equation including equipment and personnel, and provides a solution path, thereby improving the solution accuracy and applicability of temperature control transient calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 It is a structural diagram of the cabin temperature control system;

[0090] Figure 2 is a flow chart of the method of the present invention;

[0091] Figure 3 It is a curve showing the temperature inside the cabin changing with time. DETAILED DESCRIPTION

[0092] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0093] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0094] The technical problems to be solved by the present invention are:

[0095] The present invention solves the problem of transient temperature rise and fall evaluation and rapid transient numerical calculation in the temperature control design of the shelter with the characteristics of the shelter. The present invention carries out numerical calculation for the "index requirement of reaching the target temperature value within the specified time" in the indicator requirements of the shelter. In the temperature control design, the present invention comprehensively considers the influence of air conditioning power, cabin wall insulation performance, cabin equipment, air absorption and release of heat, etc. on the cabin temperature on a time scale. It realizes the intuitive display of the cabin temperature change over time, and can quickly perform iterative optimization calculations of the transient changes in the cabin temperature.

[0096] A transient temperature field state equation with the temperature control characteristics of the cabin is established to solve the problem of quantitatively calculating the temperature change on a time scale when the cabin is heated or cooled.

[0097] By introducing the average thermophysical parameters of the equipment in the cabin, a high-order differential equation including the equipment, air conditioning, cabin, and air in the cabin was constructed to improve the accuracy of transient calculations and expand the scope of application under conditions where the impact of the equipment cannot be ignored.

[0098] By disassembling high-order differential equations and using MATLAB programming to solve the temperature field state equation of the cabin temperature control system and draw the temperature rise and fall process curves, the intuitive description of the temperature change curve over time under a specific given power was solved.

[0099] against Figure 1 The cabin temperature control system shown includes air conditioning, air inlets and outlets, equipment, and cabin wall insulation, and performs transient calculations of internal temperature changes to achieve quantitative display of the final target temperature value within a specified time.

[0100] The calculation flow chart is shown in Figure 2 , the calculation process is as follows.

[0101] 1. Establish the first-order transient differential heat transfer equation:

[0102] 1.1 Transient heat transfer balance equation based on energy flow:

[0103] According to the transient heat exchange characteristics of the shelter, considering the power output of air conditioning cooling or heating in the cabin, the heat absorption of the air in the cabin, and the heat exchange between the shelter and the external environment, the transient micro-period balance equation is established as follows:

[0104] P rg =P kx +P jh (1-1);

[0105]

[0106] Among them, P rg is the air conditioner output power, P kx P is the heat absorption or heat release power of the air in the cabin, jh is the power loss of heat exchange between the cabin outer wall and the cabin environment, c k is the specific heat capacity of air, m k is the cabin air quality, T k is the average temperature of the air in the cabin, t is the time, K gx Total heat transfer coefficient of cabin, S x is the heat exchange area of ​​the cabin, ΔT jh is the average heat exchange temperature difference between inside and outside the cabin.

[0107] 1.2 Calculate the total heat transfer coefficient of the shelter:

[0108] The total heat transfer coefficient in the cabin can be obtained by two methods. When similar box materials and thicknesses are used and actual measurements can be performed, the total heat transfer coefficient value can be obtained by actual measurements according to the method described in GJB2093A-2012. When the above conditions are not met, the local heat transfer coefficient of the bulkhead is calculated first, and then the total heat transfer coefficient of the bulkhead is calculated, which can be obtained by calculation according to formula (1-3) and formula (1-4).

[0109]

[0110] Among them, K j : is the local heat transfer coefficient within the area of ​​the jth bulkhead of the cabin, in units of W / (m 2 K);

[0111] α N :Heat transfer coefficient inside the cabin, unit: W / (m 2 K);

[0112] δ i : The thickness of the i-th layer of the j-th bulkhead in the cabin insulation wall, in m;

[0113] λ i : Thermal conductivity of the i-th layer of the j-th bulkhead in the thermal insulation wall of the cabin, unit: W / (m·K);

[0114] α w : Heat transfer coefficient outside the cabin, unit: W / (m 2 K);

[0115] The total heat transfer coefficient of the bulkhead is calculated by averaging the area ratios of different materials and structures.

[0116]

[0117] Among them, K gx : is the total heat transfer coefficient of the cabin, unit is W / (m 2 K);

[0118] K j : is the local heat transfer coefficient within the area of ​​the jth bulkhead of the cabin, in units of W / (m 2 K);

[0119] S j : is the area of ​​the jth bulkhead, in m 2 .

[0120] 1.3 Calculation of logarithmic mean temperature difference of air conditioning heat exchange:

[0121] In the heat exchange process between the cabin and the outside environment, since the outside environment can be regarded as an isothermal heat sink, and in the process of heating or cooling the cabin by air conditioning, the temperature difference between the outlet air temperature and the return air temperature is large, the logarithmic mean temperature difference is used as the average heat exchange temperature difference of the cabin. The temperature difference calculation formula (1-5) is as follows:

[0122]

[0123] Where, ΔT jh is the average heat exchange temperature difference between the inside and outside of the cabin, in °C;

[0124] T kh is the air supply temperature of the air conditioner, in °C;

[0125] T kr is the return air temperature of the air conditioner, in °C;

[0126] T w is the stable temperature of the external environment, in °C;

[0127] The supply and return air temperatures of the air conditioner are related to the output power and air volume of the air conditioner, and are characteristic parameters of the air conditioner. The average temperature in the cabin is T k , which can be approximated by the air supply temperature T kh and return air temperature T kr The arithmetic mean is substituted, and the relationship between the average heat exchange temperature difference of the cabin and the average temperature in the cabin is finally established as follows:

[0128]

[0129] Among them, V k Air supply volume of air conditioner, unit: m 3 / s;

[0130] ρ k is the air density, in kg / m 3 .

[0131] 1.4 The total heat transfer differential equation is established:

[0132] After combining formula (1-2) and formula (1-6), the transient differential equation for heat transfer in the shelter (1-7) is obtained as follows:

[0133]

[0134] 2. Introduce the average thermal physical parameters of the equipment and establish a high-order differential transient heat transfer equation:

[0135] 2.1 Calculate the average specific heat capacity of the equipment:

[0136] When there are many devices placed in the cabin, the absorption or release of heat by the equipment has a significant impact on the heating or cooling time. The volume and weight of the placed equipment can be known, and the overall average specific heat capacity c of the equipment can be calculated based on the mass specific gravity of the equipment material. s , as shown in formula (2-1):

[0137]

[0138] Among them, c j is the specific heat capacity of material j, in J / (kg.k);

[0139] m j is the mass of material j, in kg.

[0140] 2.2 Construct the transient heat balance equation of the equipment:

[0141] The transient heat absorption or release of the equipment can be regarded as the change in the internal energy of the equipment, and equation (2-2) can be established as follows:

[0142]

[0143] Among them, c s is the average specific heat capacity of the equipment, in J / (kg.k);

[0144] m s is the equipment mass, in kg;

[0145] K k is the cabin air heat transfer coefficient, unit: W / (m 2 K);

[0146] S s is the heat exchange area of ​​the equipment, in m 2 ;

[0147] T ksThe temperature of the air near the equipment, in °C;

[0148] T s is the average temperature of the equipment, in °C.

[0149] 2.3 Establish a transient heat balance equation that includes the heat exchange characteristics of air conditioners, shelters, and equipment:

[0150] Since the space inside the shelter is generally relatively small, the local temperature gradient is ignored and the temperature T of the air close to the equipment is approximated. ks The average temperature in the cabin T k Equivalently, transform formula (2-2) into formula (2-3):

[0151]

[0152] Substituting formula (2-3) into formula (1-7) to establish the transient second-order differential equation group considering the influence of the equipment in the cabin on the temperature of the other cabin is as follows:

[0153]

[0154] Among them, α is the equipment heat absorption influence coefficient, and β is the air conditioning performance influence coefficient, which can be calculated according to formula (2-5) and formula (2-6).

[0155] 3. Reduction of high-order differential equations and solution with Matlab:

[0156] 3.1 Equation decomposition and reduction:

[0157] In order to solve the high-order differential equation, the differential equation of formula (2-4) is decomposed into a multivariate low-order differential equation group, and the Runge-Kutta algorithm is used in MATLAB software to quickly solve it. The decomposed equation group is as follows:

[0158]

[0159] Among them, y1' and y2' are the elements to be solved for the two-variable differential equation system;

[0160] Initial conditions:

[0161] T s The initial condition is the ambient temperature;

[0162] The initial condition is 0;

[0163] The air conditioner output power is preliminarily set within the selected range, and based on the specified heating and cooling time, the temperature change value is calculated and the temperature change curve is drawn.

[0164] 3.2 Use MATLAB's Runge-Kutta algorithm to quickly solve:

[0165] Using the first-order differential equation solution method in MATLAB software, the differential equation can be quickly solved to obtain the functional relationship between the equipment temperature and time. Then, using formula (2-3), the curve of the temperature inside the cabin changing with time can be obtained, as shown in Figure 3 Using this temperature change curve and the given power of the air conditioner, the functional relationship between the air conditioner, the cabin temperature and the given time can be quickly constructed, and the genetic algorithm toolbox in the MATLAB software can be used to achieve rapid numerical iterative optimization.

[0166] The present invention is not limited to the above-mentioned optional implementation modes. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that fall within the scope defined by the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A rapid calculation method for transient cooling and heating of shelters, characterized by: The following steps are involved: S1: Establish the first-order transient differential heat transfer equation: S11: Transient heat transfer balance equation based on energy flow; S12: Calculate the total heat transfer coefficient of the cabin; S13: Calculation of logarithmic mean temperature difference of air conditioning heat exchange; S14: The total heat transfer differential equation is established; S2: Introduce the average thermal physical property parameters of the equipment and establish a high-order differential transient heat transfer equation: S21: Calculate the average specific heat capacity of the device; S22: Construct the transient heat balance equation of the equipment; S23: Establish a transient heat balance equation including the heat transfer characteristics of air conditioners, shelters, and equipment; S3: Reduction of high-order differential equations and solution with Matlab: S31: Equation decomposition and reduction; S32: Use the Runge-Kutta algorithm of MATLAB to quickly solve.

2. The method for rapid calculation of transient cooling and heating of a shelter according to claim 1 is characterized in that: Step S11 is specifically as follows: According to the transient heat exchange characteristics of the shelter, considering the power output of air conditioning cooling or heating in the cabin, the heat absorption of the air in the cabin, and the heat exchange between the shelter and the external environment, the transient micro-period balance equation is established as follows: P rg =P kx +P jh (1-1); Among them, P rg is the air conditioner output power, P kx P is the heat absorption or heat release power of the air in the cabin, jh is the power loss of heat exchange between the cabin outer wall and the cabin environment, c k is the specific heat capacity of air, m k is the cabin air quality, T k is the average temperature of the air in the cabin, t is the time, K gx Total heat transfer coefficient of cabin, S x is the heat exchange area of ​​the cabin, ΔT jh is the average heat exchange temperature difference between inside and outside the cabin.

3. The method for rapid calculation of transient cooling and heating of a shelter according to claim 2 is characterized by: Step S12 is specifically as follows: When similar box materials and thicknesses are used and actual measurements can be performed, the total heat transfer coefficient value is obtained by actual measurement; when the conditions for measuring the heat transfer coefficient are not met, the local heat transfer coefficient of the bulkhead is calculated first, and then the total heat transfer coefficient of the bulkhead is calculated according to formula (1-3) and formula (1-4); Among them, K j : is the local heat transfer coefficient within the area of ​​the jth bulkhead of the cabin, in units of W / (m 2 K); α N :Heat transfer coefficient inside the cabin, unit: W / (m 2 K); δ i : The thickness of the i-th layer of the j-th bulkhead in the cabin insulation wall, in m; λ i : Thermal conductivity of the i-th layer of the j-th bulkhead in the thermal insulation wall of the cabin, unit: W / (m·K); α W : Heat transfer coefficient outside the cabin, unit: W / (m 2 K); The total heat transfer coefficient of the bulkhead is calculated by averaging the area ratios of different materials and structures. Among them, K gx : is the total heat transfer coefficient of the cabin, unit is W / (m 2 K); K j : is the local heat transfer coefficient within the area of ​​the jth bulkhead of the cabin, in units of W / (m 2 K); S j : is the area of ​​the jth bulkhead, in m 2 .

4. The method for rapid calculation of transient cooling and heating of a shelter according to claim 3 is characterized by: Step S13 is specifically as follows: In the heat exchange process between the cabin and the outside environment, since the outside environment can be regarded as an isothermal heat sink, and in the process of heating or cooling the cabin by air conditioning, the temperature difference between the outlet air temperature and the return air temperature is large, the logarithmic mean temperature difference is used as the average heat exchange temperature difference of the cabin. The temperature difference calculation formula (1-5) is as follows: Where, ΔT jh is the average heat exchange temperature difference between the inside and outside of the cabin, in °C; T kh is the air supply temperature of the air conditioner, in °C; T kr is the return air temperature of the air conditioner, in °C; T w is the stable temperature of the external environment, in °C; The supply and return air temperatures of the air conditioner are related to the output power and air volume of the air conditioner, and are characteristic parameters of the air conditioner. The average temperature in the cabin is T k , which can be approximated by the air supply temperature T kh and return air temperature T kr The arithmetic mean is substituted, and the relationship between the average heat exchange temperature difference of the cabin and the average temperature in the cabin is finally established as follows: Among them, V k Air supply volume of air conditioner, unit: m 3 / s; ρ k is the air density, in kg / m 3 .

5. The method for rapid calculation of transient cooling and heating of a shelter according to claim 4 is characterized in that: Step S14 is specifically as follows: After combining formula (1-2) and formula (1-6), the transient differential equation for heat transfer in the shelter (1-7) is obtained as follows:

6. The method for rapid calculation of transient cooling and heating of a shelter according to claim 5 is characterized by: Step S21 is specifically as follows: When there are many devices placed in the cabin, the absorption or release of heat by the equipment has a significant impact on the heating or cooling time. The volume and weight of the placed equipment can be known, and the overall average specific heat capacity c of the equipment can be calculated based on the mass specific gravity of the equipment material. s , as shown in formula (2-1): Among them, c j is the specific heat capacity of material j, in J / (kg.k); m j is the mass of material j, in kg.

7. The method for rapid calculation of transient cooling and heating of a shelter according to claim 6 is characterized by: Step S22 is specifically as follows: The transient heat absorption or release of the equipment is regarded as the change in the internal energy of the equipment, and equation (2-2) is established as follows: Among them, c s is the average specific heat capacity of the equipment, in J / (kg.k); m s is the equipment mass, in kg; K k is the cabin air heat transfer coefficient, unit: W / (m 2 K); S s is the heat exchange area of ​​the equipment, in m 2 ; T ks The temperature of the air near the equipment, in °C; T s is the average temperature of the equipment, in °C.

8. The method for rapid calculation of transient cooling and heating of a shelter according to claim 7 is characterized by: Step S23 is specifically as follows: Since the space inside the shelter is generally relatively small, the local temperature gradient is ignored and the temperature T of the air close to the equipment is approximated. ks The average temperature in the cabin T k Equivalently, transform formula (2-2) into formula (2-3): Substituting formula (2-3) into formula (1-7) to establish the transient second-order differential equation group considering the influence of the equipment in the cabin on the temperature of the other cabin is as follows: Among them, α is the equipment heat absorption influence coefficient, and β is the air conditioning performance influence coefficient, which can be calculated according to formula (2-5) and formula (2-6).

9. The method for rapid calculation of transient cooling and heating of a shelter according to claim 8 is characterized in that: Step S31 is specifically as follows: In order to solve the high-order differential equation, the differential equation of formula (2-4) is decomposed into a multivariate low-order differential equation group, and the Runge-Kutta algorithm is used in MATLAB software to quickly solve it. The decomposed equation group is as follows: Among them, y1' and y2' are the elements to be solved for the two-variable differential equation system; T s The initial condition is the ambient temperature; The initial condition is 0; The air conditioner output power is preliminarily set within the selected range, and based on the specified heating and cooling time, the temperature change value is calculated and the temperature change curve is drawn.

10. The method for rapid calculation of transient cooling and heating of a shelter according to claim 9 is characterized in that: Step S32 is specifically as follows: By using the first-order differential equation solution method in MATLAB software, the differential equation can be quickly solved to obtain the functional relationship between the equipment temperature and time, and then the formula (2-3) can be used to obtain the curve of the internal temperature of the cabin changing with time; using this temperature change curve, combined with the given power of the air conditioner, the functional relationship between the air conditioner, the cabin temperature, and the given time can be quickly constructed, and the genetic algorithm toolbox in MATLAB software can be used to achieve rapid numerical iterative optimization.

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