Fast calculation method for transient cooling and heating of shelters

Abstract

The present invention belongs to the field of temperature control technology for shelters, and particularly relates to a method for rapidly calculating the transient cooling and heating performance of shelters. The technical solution is as follows: a method for rapidly calculating the transient cooling and heating performance of shelters, comprising the following steps: S1: establishing a first-order transient differential heat transfer equation; S2: introducing average thermal properties of the equipment to establish a higher-order differential transient heat transfer equation; and S3: performing order reduction processing on the higher-order differential equation and solving it using MATLAB. The present invention provides a method for rapidly calculating the transient cooling and heating performance of shelters. Numerical calculations are performed based on the shelter's performance requirement of "reaching the target temperature within a specified timeframe." In temperature control design, the method comprehensively considers the time-scale effects of air conditioning power, bulkhead insulation performance, cabin equipment, and air heat absorption and release. This method allows for intuitive display of cabin temperature changes over time and rapid iterative optimization calculations of transient cabin temperature changes.

Description

Technical Field

[0001] The present 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 workspace, the shelter is widely used in medical care, emergency communications, industrial control, and other fields. Particularly in the medical rescue field, due to its strong thermal insulation and constant temperature control capabilities, it can be deployed in extreme high and low temperature environments. In addition to its overall heat transfer coefficient and the requirement for a constant temperature under extreme temperature conditions, the shelter also specifies temperature ramp times and cutoff temperature requirements under extreme temperature conditions. This ensures that the cabin reaches a comfortable temperature for occupants or a temperature for normal equipment startup and operation within a specified time under extreme temperature conditions.

[0003] Currently, key aspects of cabin temperature design (air conditioning selection and insulation design) rely primarily on numerical calculations of steady-state power consumption and general-purpose fluid flow calculation software. However, these numerical calculations only consider steady-state conditions and fail to account for temperature rise and fall times. Commonly used fluid flow calculation software, when addressing cabin temperature control issues involving air conditioning, suffers from incomplete considerations, complex modeling, and lengthy calculation times, leading to excessively high optimization iteration costs. For example, icepak cannot perform heat dissipation simulations that consider air conditioning power limits, 6sigma Room's air conditioning environment calculation module cannot perform transient simulations, and cradle and starCCM+, among others, are prohibitively expensive in terms of modeling and transient calculation time. These methods fail to fully account for the impact of transient temperature change requirements on the design, nor can they rapidly iterate and optimize the accompanying air conditioning characteristics and bulkhead insulation characteristics in the transient cabin temperature control calculations.

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

[0005] To address the aforementioned problems in the prior art, the present invention aims to provide a rapid calculation method for transient cooling and heating in a shelter. This method performs numerical calculations based on the shelter's index requirement of "reaching the target temperature value within a specified time." In temperature control design, this method comprehensively considers the effects of air conditioning power, bulkhead insulation performance, cabin equipment, and air absorption and release on the cabin temperature over time. This method enables intuitive display of cabin temperature changes over time and rapid iterative optimization calculations of transient cabin temperature changes.

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

[0007] The rapid calculation method for transient cooling and heating of a shelter 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: Establishment of the total heat transfer differential equation;

[0013] S2: Introduce the average thermal physical properties 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 the transient heat balance equation of the equipment;

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

[0017] S3: High-order differential equation reduction and MATLAB solution:

[0018] S31: Equation decomposition and reduction;

[0019] S32: Use MATLAB's Runge-Kutta algorithm to quickly solve.

[0020] This invention addresses the challenges of transient temperature rise and fall assessment and rapid transient numerical calculation in modular cabin temperature control design, specifically designed for modular cabins. Numerical calculations are performed to address the modular cabin's performance requirement of "reaching the target temperature within a specified timeframe." In temperature control design, this invention comprehensively considers the temporal impact of air conditioning power, bulkhead insulation, cabin equipment, and air heat absorption and release. This invention visually displays cabin temperature changes over time and allows for rapid iterative optimization of transient cabin temperature changes.

[0021] The present invention establishes a transient temperature field state equation with the characteristics of cabin temperature control, and solves the problem of quantitatively calculating temperature changes on a time scale when the cabin 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 that includes the equipment, air conditioning, cabin, and cabin air, which improves the accuracy of transient calculations and expands the scope of application under conditions where the influence of equipment cannot be ignored.

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

[0024] As a preferred embodiment 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 to the cabin, the heat absorption of the cabin air, and the heat exchange between the cabin body 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 from heat exchange between the cabin outer wall and the environment outside the cabin, 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 the 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 embodiment of the present invention, step S12 is specifically as follows:

[0030] When using a similar box material and thickness, and actual measurement is possible, the total heat transfer coefficient value is obtained by actual measurement; when the conditions for actual measurement of the heat transfer coefficient are not available, first calculate the local heat transfer coefficient of the bulkhead, and then calculate the total heat transfer coefficient of the bulkhead 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 j-block bulkhead of the cabin, unit 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 material of the j-th bulkhead in the cabin insulation wall, in m;

[0035] λ i : thermal conductivity of the i-th layer of material 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 occupied by 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 j-block bulkhead of the cabin, unit W / (m 2 K);

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

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

[0043] During the heat exchange process between the cabin and the outside environment, the outside environment can be regarded as an isothermal heat sink, and in the process of air conditioning heating or cooling the cabin, the temperature difference between the outlet air temperature and the return air temperature is large. Therefore, 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, unit is ℃;

[0047] T kr is the return air temperature of the air conditioner, unit is ℃;

[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 T k, which can be approximated by the air supply temperature T kh and return air temperature T kr The arithmetic mean is used as the substitute, and the relationship between the average heat transfer temperature difference of the cabin and the average temperature inside the cabin is finally established as follows:

[0050]

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

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

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

[0054] By 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 embodiment of the present invention, step S21 is specifically as follows:

[0057] When there are many devices placed in the cabin, the heat absorbed or released by the devices will have a significant impact on the heating or cooling time. The volume and weight of the placed devices can be known, and the overall average specific heat capacity c of the devices can be calculated based on the mass ratio of the equipment materials. 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 embodiment 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 mass of the equipment, in kg;

[0066] K k is the cabin air heat transfer coefficient, unit is 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, unit: °C;

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

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

[0071] Since the space inside the cabin is generally relatively small, the local temperature gradient is ignored and the temperature of the air close to the equipment is approximately T 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) establishes the transient second-order differential equations that take into account the influence of the cabin equipment on the cabin temperature as follows:

[0074]

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

[0076] As a preferred embodiment 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 system, and the Runge-Kutta algorithm is used in MATLAB software to quickly solve it. The decomposed equation system is as follows:

[0078]

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

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

[0081] The initial condition is 0;

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

[0083] As a preferred embodiment 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. Then, formula (2-3) is used to obtain the curve of the internal temperature of the cabin changing with time. By using this temperature change curve and combining it 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. The genetic algorithm toolbox in MATLAB software is 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, which enables 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 cabin temperature control system design, which facilitates the comparison of transient temperature control indicators.

[0088] 3. Based on conventional transient calculations, this invention introduces the average thermophysical parameters of equipment and personnel, constructs a high-order differential equation involving 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 This is a schematic diagram of the structure 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] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only 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 herein 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 rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features therein may be combined with each other unless there is a conflict.

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

[0095] This invention addresses the challenges of transient temperature rise and fall assessment and rapid transient numerical calculation in modular cabin temperature control design. It performs numerical calculations based on the modular cabin's performance requirement of "reaching the target temperature within a specified timeframe." In temperature control design, the invention comprehensively considers the temporal impact of air conditioning power, bulkhead insulation, cabin equipment, and air heat absorption and release. This allows for intuitive display of cabin temperature changes over time and rapid iterative optimization of transient cabin temperature changes.

[0096] A transient temperature field state equation with the temperature control characteristics of the cabin is established to solve the problem of quantitatively calculating temperature changes 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 cabin air was constructed to improve the accuracy of transient calculations and expand the scope of application under conditions where the influence of equipment cannot be ignored.

[0098] By decomposing 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 achieved.

[0099] against Figure 1 The cabin temperature control system shown includes air conditioning, air inlets and outlets, equipment, and bulkhead insulation. It performs transient calculations of internal temperature changes and quantitatively displays 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 to the cabin, the heat absorption of the cabin air, and the heat exchange between the cabin body 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 from heat exchange between the cabin outer wall and the environment outside the cabin, 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 the 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.

[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 are possible, the total heat transfer coefficient value can be obtained by actual measurement 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. It can be obtained by calculation according to formulas (1-3) and (1-4).

[0109]

[0110] Among them, K j : is the local heat transfer coefficient within the area of ​​the j-block bulkhead of the cabin, unit 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 material of the j-th bulkhead in the cabin insulation wall, in m;

[0113] λ i : thermal conductivity of the i-th layer of material 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 occupied by 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 j-block bulkhead of the cabin, unit 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] During the heat exchange process between the cabin and the outside environment, the outside environment can be regarded as an isothermal heat sink, and in the process of air conditioning heating or cooling the cabin, the temperature difference between the outlet air temperature and the return air temperature is large. Therefore, 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, unit is ℃;

[0125] T kr is the return air temperature of the air conditioner, unit is ℃;

[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 T k , which can be approximated by the air supply temperature T kh and return air temperature T kr The arithmetic mean is used as the substitute, and the relationship between the average heat transfer temperature difference of the cabin and the average temperature inside the cabin is finally established as follows:

[0128]

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

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

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

[0132] By 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 heat absorbed or released by the devices will have a significant impact on the heating or cooling time. The volume and weight of the placed devices can be known, and the overall average specific heat capacity c of the devices can be calculated based on the mass ratio of the equipment materials. 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 the 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 mass of the equipment, in kg;

[0145] K k is the cabin air heat transfer coefficient, unit is 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, unit: °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 transfer characteristics of air conditioning, shelters, and equipment:

[0150] Since the space inside the cabin is generally relatively small, the local temperature gradient is ignored and the temperature of the air close to the equipment is approximately T 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) establishes the transient second-order differential equations that take into account the influence of the cabin equipment on the cabin temperature as follows:

[0153]

[0154] Among them, α is the equipment heat absorption coefficient, and β is the air conditioning performance 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 order 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 system, and the Runge-Kutta algorithm is used in MATLAB software to quickly solve it. The decomposed equation system is as follows:

[0158]

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

[0160] Initial conditions:

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

[0162] The initial condition is 0;

[0163] The output power of the air conditioner is preliminarily set within the selected range, and the temperature change value is calculated based on the specified heating and cooling time, 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 cabin internal temperature changing with time is obtained, as shown in the following example: Figure 3 Using this temperature variation curve and the given air conditioning power, we can quickly build a functional relationship between the air conditioning, cabin temperature, and given time. Using the genetic algorithm toolbox in MATLAB software, we can achieve rapid numerical iterative optimization.

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

Claims

1. A rapid calculation method for transient cooling and heating of a shelter, 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: Establishment of the total heat transfer differential equation; S2: Introduce the average thermal physical properties 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 that includes the heat transfer characteristics of air conditioners, shelters, and equipment; S3: High-order differential equation reduction and MATLAB solution: S31: Equation decomposition and reduction; S32: Use MATLAB's Runge-Kutta algorithm to quickly solve.

2. The method for rapid calculation of transient cooling and heating in a shelter according to claim 1 is characterized by: 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 to the cabin, the heat absorption of the cabin air, and the heat exchange between the cabin body 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 from heat exchange between the cabin outer wall and the environment outside the cabin, 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 the 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.

3. The method for rapid calculation of transient cooling and heating in a shelter according to claim 2 is characterized by: Step S12 is specifically as follows: When using a similar box material and thickness, and actual measurement is possible, the total heat transfer coefficient value is obtained by actual measurement; when the conditions for actual measurement of the heat transfer coefficient are not available, first calculate the local heat transfer coefficient of the bulkhead, and then calculate the total heat transfer coefficient of the bulkhead according to formula (1-3) and formula (1-4); Among them, K j : is the local heat transfer coefficient within the area of ​​the j-block bulkhead of the cabin, unit 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 material of the j-th bulkhead in the cabin insulation wall, in m; λ i : thermal conductivity of the i-th layer of material 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 occupied by 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 j-block bulkhead of the cabin, unit 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 in a shelter according to claim 3 is characterized by: Step S13 is specifically as follows: During the heat exchange process between the cabin and the outside environment, the outside environment can be regarded as an isothermal heat sink, and in the process of air conditioning heating or cooling the cabin, the temperature difference between the outlet air temperature and the return air temperature is large. Therefore, 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, unit is ℃; T kr is the return air temperature of the air conditioner, unit is ℃; 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 T k , which can be approximated by the air supply temperature T kh and return air temperature T kr The arithmetic mean is used as the substitute, and the relationship between the average heat transfer temperature difference of the cabin and the average temperature inside the cabin is finally established as follows: Among them, V k Air supply volume for air conditioning, unit: m 3 / s; ρ k is the air density, unit is kg / m 3 .

5. The method for rapid calculation of transient cooling and heating in a shelter according to claim 4 is characterized in that: Step S14 is specifically as follows: By 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 in 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 heat absorbed or released by the devices will have a significant impact on the heating or cooling time. The volume and weight of the placed devices can be known, and the overall average specific heat capacity c of the devices can be calculated based on the mass ratio of the equipment materials. 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 in 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 the 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 mass of the equipment, in kg; K k is the cabin air heat transfer coefficient, unit is 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, unit: °C; T s is the average temperature of the equipment, in °C.

8. The method for rapid calculation of transient cooling and heating in a shelter according to claim 7 is characterized by: Step S23 is specifically as follows: Since the space inside the cabin is generally relatively small, the local temperature gradient is ignored and the temperature of the air close to the equipment is approximately T 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) establishes the transient second-order differential equations that take into account the influence of the cabin equipment on the cabin temperature 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 in a shelter according to claim 8, 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 system, and the Runge-Kutta algorithm is used in MATLAB software to quickly solve it. The decomposed equation system is as follows: Among them, y1' and y2' are the elements to be solved for the system of two-variable differential equations; T s The initial condition is the ambient temperature; The initial condition is 0; The output power of the air conditioner is preliminarily set within the selected range, and the temperature change value is calculated based on the specified heating and cooling time, 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, 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. Then, formula (2-3) is used to obtain the curve of the internal temperature of the cabin changing with time. By using this temperature change curve and combining it 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. The genetic algorithm toolbox in MATLAB software is used to achieve rapid numerical iterative optimization.

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