Dynamic air conditioning load prediction method for non-enclosed tall spaces based on thermal stratification

Abstract

The present invention discloses a method for predicting the dynamic air-conditioning load in a non-enclosed tall space based on thermal stratification. The method includes first defining the initial values of environmental analysis parameters; then obtaining the air flow deflection degree in the air-conditioning area according to the interlayer temperature distribution in the central block and the air-conditioning area; next, based on the inner wall surface temperature and the air flow deflection degree in the central space at the current moment, obtaining the interlayer temperature distribution in the central block and the air-conditioning area at the next moment; obtaining the inner wall surface temperature in the central space at the next moment based on the total heat balance equation and the interlayer temperature distribution in the central block and the air-conditioning area; and finally obtaining the air-conditioning load in the air-conditioning area based on the interlayer temperature distribution. The present invention is used to predict the convective heat transfer dynamic load from the non-enclosed tall space around to the surrounding air-conditioning areas, realizes the dynamic calculation of air temperature and wall surface temperature, and finally obtains the prediction result of the convective heat transfer dynamic load from the non-enclosed tall space around to the surrounding air-conditioning areas through the convective flow rate and air temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of dynamic prediction of heating and cooling loads in high and large space buildings, and particularly relates to a method for predicting dynamic air-conditioning loads in non-enclosed high and large spaces based on thermal stratification. Background Technique

[0002] In engineering, buildings with an indoor net height greater than 10m and a volume greater than 10,000m 3 are generally defined as high and large space buildings. In high and large space buildings, there is a common thermal environment phenomenon of uneven vertical air temperature distribution indoors, which is usually defined as vertical thermal stratification. Heat stays at the top of the space for a long time, while the air temperature at the bottom of the space is often low, which will not only interfere with the thermal comfort of users, but also easily increase the energy consumption burden of space cooling or heating. Therefore, accurately predicting the heating and cooling loads of such spaces is particularly crucial for environmental creation and space cooling and heating design.

[0003] According to the connection relationship between the space and other surrounding spaces, high and large spaces can be divided into two categories: enclosed and non-enclosed. The former is surrounded by enclosing structures and belongs to a single space, which is common in buildings such as airport waiting halls, terminals, and stadiums. In actual engineering, only the thermal environment of the bottom use area of the space is usually concerned, and the design method of stratified air conditioning is generally adopted; the latter is directly connected to the surrounding activity areas on all sides, and is mostly found in modern large public buildings such as large shopping malls and comprehensive hospitals in complexes. In addition to the thermal environment of the bottom activity area, the thermal environment of the upper space will also interact with the thermal environment of the surrounding air-conditioned areas, and interfere with the thermal comfort and heating and cooling loads of the users in the surrounding air-conditioned areas. Accurately calculating and predicting the dynamic convective heat transfer load in this part has quite important practical value for the energy-saving design of such building spaces and carbon emission reduction in the later operation stage.

[0004] However, there are the following deficiencies in the existing calculation process of heating and cooling loads in high and large space buildings: 1. Ignoring the calculation of the convective heat transfer load of non-enclosed high and large spaces to the directly connected air-conditioned areas around; 2. Or due to the failure to accurately describe the mass and heat transfer processes between non-enclosed high and large spaces and the directly connected air-conditioned areas around during the operation stage, resulting in large errors in load calculation. Summary of the Invention

[0005] In order to solve the problems existing in the background technique, the purpose of the present invention is to provide a method for predicting dynamic air-conditioning loads in non-enclosed high and large spaces based on thermal stratification, which is used to dynamically predict the convective heat transfer load of non-enclosed high and large spaces around to the surrounding air-conditioned areas, so as to solve problems such as the load quantity generated by the convective heat transfer of such spaces to the surrounding air-conditioned areas not being considered in engineering applications, the inaccurate load calculation caused by not considering the thermal stratification situation, and only calculating static loads while ignoring the influence brought by the dynamic changes of the external environment.

[0006] The technical solution adopted by the present invention is as follows, including the following steps:

[0007] Step S1: First, define the initial values of the environmental analysis parameters; the environmental analysis parameters include the interlayer temperature distribution of the central block and the air-conditioning area, and the inner wall surface temperatures of the roof and the ground of the central space.

[0008] Specifically, the space in the high-rise building is regarded as a high-rise space, the height of the high-rise space is greater than 5m, and the volume is greater than 10000m 3 , and a circle of air-conditioning areas directly connected to the central space is arranged around the high-rise space (central space), and the central space and the air-conditioning area are regarded as a non-enclosed high-rise space in the building.

[0009] The high-rise space is evenly divided into M layers of central blocks from bottom to top, and the air-conditioning space is evenly divided into M layers of air-conditioning areas from bottom to top. The central block and the air-conditioning area on the same layer are in the same horizontal direction, that is, the upper surface of the mth layer central block is flush with the upper surface of the mth layer air-conditioning area.

[0010] Step S2: According to the interlayer temperature distribution of the central block and the air-conditioning area at the current moment, obtain the horizontal convective mass flow rate of air between the current air-conditioning area and the central block, and the airflow deflection degree of each layer of the air-conditioning area.

[0011] Step S3: Based on the inner wall surface temperatures of the roof and the ground of the central space at the current moment, and the airflow deflection degree of the air-conditioning area, obtain the interlayer temperature distribution of the central block and the air-conditioning area at the next moment.

[0012] Step S4: Construct a total heat balance equation set, and based on the total heat balance equation and the interlayer temperature distribution of the central block and the air-conditioning area in Step S3, obtain the inner wall surface temperatures of the roof and the ground of the central space at the next moment.

[0013] Step S5: Based on the interlayer temperature distribution of the air-conditioning area at the current moment, obtain the air-conditioning load of the air-conditioning area at this moment.

[0014] Steps S2 to S5 constitute a complete air-conditioning load prediction process at one moment. Continuously update the moment of air-conditioning operation, update the moment n to n + 1 each time, and repeat Steps S2 to S5 multiple times to obtain the air-conditioning loads of the air-conditioning areas at different moments, so as to realize the prediction of the air-conditioning loads of the air-conditioning areas around the central space during the air-conditioning operation process.

[0015] The specific content of Step S2 is as follows:

[0016] Step S2.1: First, according to the interlayer temperature distribution T of the central block a,m(n) and the interlayer temperature distribution T of the air-conditioning area b,m(n)The air horizontal convection mass flow rate M between each layer of air-conditioning areas and the central block is obtained by the following formula ab,m(n) :

[0017]

[0018] T ab,m(n) =(T a,m(n) +T b,m(n) ) / 2

[0019] In the formula, M ab,m(n) represents the air convection mass flow rate between the air-conditioning area on the m-th floor and the central block on the m-th floor at the n-th moment; ρ represents the air density; C d represents the dimensionless correction coefficient for the convection mass flow rate considering viscous forces, usually taking a value of 0.5 - 0.7; C a represents the cross-sectional perimeter of the central block; T a,m(n) represents the interlayer temperature distribution of the central block on the m-th floor at the n-th moment; T b,m(n) represents the interlayer temperature distribution of the air-conditioning area on the m-th floor at the n-th moment; T ab,m(n) represents the mixed temperature of the air-conditioning area on the m-th floor and the central block on the m-th floor at the n-th moment; g represents the acceleration due to gravity; h b,m represents the height of the air contact surface between the air-conditioning area on the m-th floor and the central block on the m-th floor, that is, the size of the contact surface between the air-conditioning area on the m-th floor and the central block in the vertical direction;

[0020] Step S2.2. Next, the airflow deflection degree D of each layer of air-conditioning areas is obtained by the following formula a,m(n) :

[0021]

[0022] In the formula, D a,m(n) represents the dimensionless airflow deflection degree of the convective overflow airflow in the air-conditioning area on the (m - 1)-th floor in the air-conditioning area on the m-th floor at the n-th moment, D a,1(n) =0; h bn,m represents the height of the pressure neutral surface of the air contact surface between the air-conditioning area on the m-th floor and the central block on the m-th floor, h bn,m =1 / 3 - 1 / 2h b,m ;

[0023] Step S2.3. Judge the airflow deflection degree D a,m(n) of the air-conditioning area:

[0024] If the airflow deflection degree D a,m(n) of the air-conditioning area is less than the preset critical threshold, and the critical threshold generally takes 0.255, it indicates that the convective overflow airflow in the air-conditioning area on the (m - 1)-th floor flows into the air-conditioning area on the m-th floor at the n-th moment;

[0025] Otherwise, it indicates that the convective overflow air flow in the air conditioning area on the (m - 1)-th layer at time n does not flow into the air conditioning area on the m-th layer, and the convective overflow air flow in the air conditioning area on the (m - 1)-th layer continues to flow vertically along the original path.

[0026] In different seasons, the sorting method of the air conditioning areas is different: in summer, the sorting method of the air conditioning areas is from top to bottom, that is, the top layer is the 1st layer and the bottom layer is the M-th layer; in winter, it is the opposite, that is, the bottom layer is the 1st layer and the top layer is the M-th layer.

[0027] The specific steps of step S3 are as follows:

[0028] Step S3.1: First, according to the horizontal convective mass flow rate M of the air at the current time n ab,m(n) , and the inner wall surface temperatures of the central space roof and the ground, the interlayer temperature distribution T of the central block at the next time n + 1 is obtained according to the following formula: a,m(n+1) :

[0029] M a,m-1(n) -M a,m(n) -M ab,m(n) +M in,m(n) = 0

[0030] c p M a,m-1(n) T a,m-1(n+1) -c p M a,m(n) T a,m(n+1) -c p M ab,m(n) T a,m(n+1) +C B A a (T a,m-1(n+1) -T a,m(n+1) )

[0031] -C B A a (T a,m(n+1) -T a,m+1(n+1) )+h r A r (T r(n) -T a,1(n+1) )+h f A f (T f(n) -T b,M(n) )+c p M in,m(n) T ab,M(n) = 0

[0032] Among them, M a,m(n) represents the mass flow rate flowing vertically from the central block on the m-th layer into the central block on the (m + 1)-th layer at time n, M a,0(n) = 0; M in,m(n)Represents the air mass flow rate flowing into the central block in the air-conditioned area at time n, M in,m(n) Is formed by the convective overflow airflows in each layer of the air-conditioned area and only appears on the Mth layer. The value on the remaining floors is 0; c in,m(n) ; c p Represents the specific heat capacity of air; C B Represents the convective heat transfer coefficient of the vertical temperature difference between adjacent layers of the central block, usually taking a value of 2.3; A a Represents the air contact area between adjacent layers of the central block; A r Represents the inner wall area of the roof of the central space; A f Represents the inner wall area of the ground of the central space; h r Represents the convective heat transfer coefficient between the roof of the central space and the air in the topmost central block; h f Represents the convective heat transfer coefficient between the ground of the central space and the air in the bottommost central block; T r(n) Represents the inner wall temperature of the roof of the central space at time n; T f(n) Represents the inner wall temperature of the ground of the central space at time n; M represents the total number of layers of the air-conditioned area / central block;

[0033] Due to the density difference, the convective overflow airflows in each floor of the air-conditioned area usually flow vertically after overflow. Therefore, it is regarded as the air flow interlayer area between the central space and the surrounding air-conditioned areas. After judging whether the airflows deflect at each floor in step S2, based on their actual flow states at time n, the heat conservation equation needs to be written as follows and the vertical temperature distribution of the equation at time n is calculated, that is, T c,m(n) of the data set;

[0034] Step S3.2. Then, according to the airflow deflection degrees of each layer of the air-conditioned area, the temperature distribution of each layer of the contact block is obtained by processing according to the following formula. The contact block represents the area where the air in the air-conditioned area and the central block are in contact with each other:

[0035] c p M ab,m(n) T a,m(n+1) +c p M ba,m(n) T b,m(n) +c p M c,m-1(n) T c,m-1(n+1) -c p M c,m(n) T c,m(n+1)

[0036] -c p M cb,m(n) T c,m(n+1) -c p M in,m(n) T c,M(n+1) = 0

[0037] M ba,m(n) = M ab,m(n)

[0038] wherein, T c,m(n+1) represents the air temperature distribution of the contact block in the m-th layer at the (n + 1)-th moment; M ba,m(n) represents the convective overflow mass flow rate of the air-conditioning area in the m-th layer at the n-th moment; M c,m(n) represents the mass flow rate flowing from the contact block in the m-th layer to the contact block in the (m + 1)-th layer at the n-th moment; M cb,m(n) represents the mass flow rate flowing from the contact block in the m-th layer to the air-conditioning area in the m-th layer at the n-th moment;

[0039] In the above formula, the mass flow rate M of the contact block flowing to the air-conditioning area cb,m(n) is taken as follows:

[0040] If the convective overflow air flow in the air-conditioning area of the (m - 1)-th layer at the n-th moment flows into the air-conditioning area of the m-th layer, then M cb,m(n) = M ab,m(n) + M c,m-1(n) ;

[0041] If the convective overflow air flow in the air-conditioning area of the (m - 1)-th layer at the n-th moment does not flow into the air-conditioning area of the m-th layer, then M cb,m(n) = M ab,m(n) ;

[0042] Step S3.3. Then, according to the temperature distribution of the contact block, the interlayer temperature distribution T of the air-conditioning area at the next moment (n + 1) is obtained according to the following formula b,m(n+1) :

[0043] c p M cb,m(n) T c,m(n+1) + c p M s,m(n) T s - c p M ab,m(n) T b,m(n+1) - c p M cb,m(n) T b,m(n+1) = 0

[0044] M s,m(n) = M ab,m(n)

[0045] wherein, M s,m(n) represents the supplementary air flow mass flow rate of the air-conditioning supply air to the air-conditioning area in the m-th layer at the n-th moment; T s represents the set temperature of the air-conditioning area.

[0046] The specific step S4 is as follows:

[0047] Step S4.1: First, construct a rectangular closed enclosure structure around the central space. The six enclosure panels of the enclosure structure are respectively arranged at the six boundaries of the central space, and the central space is rectangular in shape. Take the two enclosure panels at the top and bottom of the enclosure structure as two enclosure units respectively, and evenly divide the four enclosure panels around the enclosure structure into M enclosure units along the vertical direction. Therefore, a total of 4M + 2 enclosure units are divided. Then, use a division plane perpendicular to the thickness direction of the enclosure unit to evenly divide the enclosure unit, so that the enclosure unit is divided into multiple discrete layer structures with uniform distribution of thermophysical parameters, and take all the division planes, the inner wall surface and the outer wall surface of the enclosure unit as the discrete surfaces of the enclosure unit.

[0048] The inner wall surface and the outer wall surface of the enclosure unit are respectively two wall surfaces symmetrically distributed along the thickness direction of the enclosure unit. The discrete surfaces are counted from the inner side to the outer side of the enclosure unit. The inner wall surface of the enclosure unit is used as the first discrete surface, and the outer wall surface of the enclosure unit is used as the Kth discrete surface, where K is the total number of discrete surfaces.

[0049] Obtain the heat balance equations for the inner wall surface, the division plane and the outer wall surface of the enclosure unit according to the following formulas:

[0050] Inner wall surface:

[0051]

[0052] Division plane:

[0053]

[0054] Outer wall surface:

[0055]

[0056] In the formula: τ represents the calculated time step, that is, the difference between the nth moment and the (n - 1)th moment; c p,k(i) represents the specific heat capacity of the material of the kth discrete surface in the ith enclosure unit; ρ k(i) represents the material density of the kth discrete surface in the ith enclosure unit; Δx k(i) represents the thickness of the kth discrete surface in the ith enclosure unit. If the discrete surface has only one adjacent discrete layer, the thickness of the discrete surface is equal to half of the thickness of the discrete layer structure adjacent to the discrete surface; if the discrete surface has two adjacent discrete layers, the thickness of the discrete surface is equal to the average value of the thicknesses of the two discrete layer structures adjacent to the discrete surface; t k(i) represents the temperature of the kth discrete surface in the ith enclosure unit; h k(i) represents the surface convective heat transfer coefficient of the kth discrete surface in the ith enclosure unit; t a,k(i) represents the air temperature adjacent to the surface of the kth discrete surface in the ith enclosure unit; K k(i)Denote the thermal conductivity of the material of the discrete surface of the k-th layer in the i-th enclosure unit; hr j,k(i) Denote the surface long-wave radiation heat transfer coefficient of the discrete surface of the k-th layer in the i-th enclosure unit by the j-th enclosure unit; t j,k(i) Denote the surface temperature of the discrete surface of the k-th layer in the i-th enclosure unit by the j-th enclosure unit; q rad,k(i) Denote the radiant heat obtained on the surface of the discrete surface of the k-th layer in the i-th enclosure unit; K denotes the total number of layers of the discrete surface in the i-th enclosure unit;

[0057] Among the above, the surface long-wave radiation heat transfer coefficient hr j,k(i) Is obtained by processing according to the following formula:

[0058] hr j,k(i) =G k(i),j ·ε k(i) ·σ·(t k(i) 2 +t k(j) 2 )(t k(i) +t k(j) )

[0059] In the formula, G k,j(i) Denote the radiation absorption coefficient of the discrete surface of the k-th layer in the i-th enclosure unit by the j-th enclosure unit; ε k(i) Denote the radiation emissivity of the discrete surface of the k-th layer in the i-th enclosure unit; σ denotes the blackbody radiation constant, with a value of 5.67e-8; t k(j) Denote the temperature of the discrete surface of the k-th layer in the j-th enclosure unit;

[0060] Step S4.2, construct the total heat balance equation set composed of the discrete surfaces of all enclosure units in the central space:

[0061]

[0062] Among them, C represents the total heat storage capacity matrix under the unit temperature change rate; T represents the total temperature matrix; A represents the total heat transfer relationship matrix; B represents the total heat disturbance parameter action matrix; u(n) represents the heat disturbance vector related to the heat process at the n-th moment; Denote the differential matrix obtained by differentiating the temperature variables in the total temperature matrix T;

[0063] In the above formula, the heat disturbance vector u(n) is determined by the interlayer temperature distribution T a,m(n) Of the central block and the interlayer temperature distribution T b,m(n) Of the air-conditioned area, and the expression of the heat disturbance vector u(n) is as follows:

[0064] u(n)=[T e(n) ,T ug(n) ,Ta(n) , T b(n) , q solar(n) , q dir(n) , q dif(n) , q indoor(n) T

[0065] When in winter time, T a(n) = [T a,1(n) , T a,2(n) , …, T a,M(n)

[0066] When in summer time, T a(n) = [T a,M(n) , T a,M-1(n) , …, T a,1(n)

[0067] When in winter time, T b(n) = [T b,1(n) , T b,2(n) , …, T b,M(n)

[0068] When in summer time, T b(n) = [T b,M(n) , T b,M-1(n) , …, T b,1(n)

[0069] In the formula, T e(n) represents the outdoor air temperature at time n; T ug(n) represents the basement air temperature at time n; T a(n) represents the central block interlayer temperature distribution data set; T b(n) represents the air-conditioned area interlayer temperature distribution data set; q solar(n) represents the outdoor net solar radiation intensity at time n; q dir(n) represents the indoor direct solar radiation intensity through the window at time n; q dif(n) represents the indoor diffuse solar radiation intensity through the window at time n; q indoor(n) represents the indoor heat source heat generation at time n.

[0070] Step S4.3: Use the heat disturbance vector u(n) at the current time n to obtain the inner wall surface temperature T r(n+1) of the roof of the central space and the inner wall surface temperature T f(n+1) of the floor of the central space at the next time n + 1.

[0071] In the said step S4.2, the expression of the total heat storage capacity matrix C is as follows:

[0072]

[0073] Among them, C i ​​​​​It represents the heat storage capacity matrix of the i-th enclosure unit, M represents the total number of floors in the air-conditioned area; c p,k(i) It represents the specific heat capacity of the material of the k-th discrete surface in the i-th enclosure unit; ρ k(i) It represents the material density of the k-th discrete surface in the i-th enclosure unit; Δx k(i) It represents the thickness of the k-th discrete surface in the i-th enclosure unit; S i It represents the surface area of the i-th enclosure unit;

[0074] In the said step S4.2, the expression of the total heat transfer relationship matrix A is as follows:

[0075]

[0076]

[0077] Among them, A i It represents the heat transfer relationship matrix of the i-th enclosure unit; A LWR,i,j It represents the long-wave radiation heat transfer matrix between the inner surfaces of the i-th and j-th enclosure units of order K×K; h k(i) It represents the surface convective heat transfer coefficient of the k-th discrete surface in the i-th enclosure unit; K k(i) It represents the material thermal conductivity of the k-th discrete surface in the i-th enclosure unit; hr j,k(i) It represents the surface long-wave radiation heat transfer coefficient of the j-th enclosure unit to the k-th discrete surface in the i-th enclosure unit; hr i,j It represents the radiation heat transfer coefficient of the j-th enclosure unit to the i-th enclosure unit;

[0078] In the said step S4.2, the expression of the total heat disturbance parameter action matrix B is as follows:

[0079] B = [B1, B2, …, B i , …, B 4M+2 T

[0080]

[0081] In the formula: B i It represents the heat disturbance parameter action matrix of the i-th enclosure unit of order K×(2M + 6); k dir,i It represents the proportion of direct solar radiation received through the window on the inner wall surface of the i-th enclosure unit; k dif,i It represents the proportion of diffuse solar radiation received through the window on the inner surface of the i-th enclosure unit; k indoor,i It represents the proportion of heat generated by indoor heat sources received on the inner surface of the i-th enclosure unit. Among them, the outdoor air temperature and outdoor solar radiation directly act on the roof enclosure structure. When the roof is made of transparent material, the solar radiation entering the room will also act on the ground or other indoor wall surfaces.​

[0082] Thermal disturbance parameter action matrix B i It can be split into four parts for representation:

[0083] B i =[B i,1 , B i,2 , B i,3 , B i,4

[0084]

[0085]

[0086] Among them, the number of columns of matrix B i,2 and matrix B i,3 is both M columns.

[0087] In the step S4.3, based on the thermal disturbance vector u(n), the method for obtaining the inner wall surface temperatures of the central space roof and the ground is as follows:

[0088] According to the total heat storage capacity matrix C and the thermal disturbance vector u(n), the inner wall surface temperature distribution T r,f(n) of the central space is obtained according to the following formula:

[0089] T r,f(n) =[T r(n) , T f(n) = DT (n)

[0090]

[0091] Among them, τ represents the calculated time step, that is, the difference between the nth moment and the (n - 1)th moment; T r,f(n) represents the inner wall surface temperature distribution of the central space at the nth moment; Q represents the transition matrix; P represents an invertible matrix composed of the eigenvectors of the transition matrix Q; Λ represents a diagonal matrix with the eigenvalues of the transition matrix Q as diagonal elements; e represents the natural number; ξ represents the time variable; D represents an intermediate matrix, and the number of rows of the intermediate matrix D is the total number of all discrete surfaces in the central space; the number of columns is the total number of all elements in the thermal disturbance vector u(n).

[0092] The specific step S5 is as follows:

[0093] According to the interlayer temperature distribution in the air-conditioned area, the air-conditioning load Q at the current moment n is processed and obtained according to the following formula: ffb,m(n) :

[0094] Q ffb,m(n) =c p ·M cb,m(n) ·|T s,m(n) - T​b,m(n) |

[0095] Among them, Q ffb,m(n) represents the air-conditioning load of the central block on the m-th floor flowing to the air-conditioning area on the i-th floor through convective heat transfer at the n-th moment; M cb,m(n) represents the mass flow rate of the central block on the m-th floor flowing to the air-conditioning area on the m-th floor at the n-th moment; T s,m(n) represents the set temperature of the air-conditioning area on the i-th floor at the n-th moment; T b,m(n) represents the air temperature of the air-conditioning area on the i-th floor at the n-th moment.

[0096] Based on the convective flow rate distribution and air temperature distribution at each moment, the dynamic load distribution within the calculation period can be obtained, which is mainly used for dynamically predicting the convective heat transfer load from the non-enclosed tall space around to the surrounding air-conditioning areas.

[0097] The seasons applicable to the method of the present invention are mainly winter and summer when air-conditioning is required. The applicable object of the method of the present invention is a non-enclosed tall space with obvious thermal stratification phenomenon. There is no heating, ventilation and air-conditioning system installed inside the non-enclosed tall space body, and heating, ventilation and air-conditioning systems are installed in the surrounding air-conditioning areas and are directly connected to the large space.

[0098] The prediction method of the present invention clarifies the air heat transfer and mass transfer mechanism between the non-enclosed tall space and the surrounding multi-layer air-conditioning areas. Then, based on the mass and heat conservation equations, the vertical temperature distribution and convective heat transfer amount between the space body and the surrounding air-conditioning areas are solved, and the dynamic calculation of air temperature and wall temperature is realized by combining the state space method. Finally, the prediction result of the convective heat transfer dynamic load from the non-enclosed tall space to the surrounding air-conditioning areas is obtained through the set convective flow rate and air temperature within the calculation period;

[0099] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0100] 1. Based on the mass and heat conservation equations, the present invention solves the vertical temperature distribution and convective heat transfer amount between the space body and the surrounding air-conditioning areas, realizes the dynamic calculation of air temperature and wall temperature, and finally obtains the prediction result of the convective heat transfer dynamic load from the non-enclosed tall space to the surrounding air-conditioning areas through the convective flow rate and air temperature;

[0101] 2. The present invention can be used to predict the convective heat transfer dynamic load from the non-enclosed tall space around to the surrounding air-conditioning areas. Compared with the traditional tall space load calculation method, it solves the problems in engineering applications such as not considering the load caused by the convective heat transfer from this type of space to the surrounding air-conditioning areas, inaccurate load calculation caused by not considering the thermal stratification situation, and only calculating the static load while ignoring the influence brought by the dynamic changes of the external environment. Description of the Drawings

[0102] Figure 1Flow chart of a dynamic air-conditioning load prediction method for non-enclosed tall spaces based on thermal stratification provided by the present invention;

[0103] Figure 2 Schematic diagram of the spatial form section of the non-enclosed tall space involved in the present invention. Detailed implementation manners

[0104] In order to make the objectives, technical solutions and beneficial effects of the present invention clearer and more specific, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0105] The embodiment is the core atrium in a large commercial complex in Hangzhou, Zhejiang Province, and its spatial form and building operation mode are consistent with the characteristics of the non-enclosed tall space involved in the present invention.

[0106] The present invention provides a dynamic air-conditioning load prediction method for non-enclosed tall spaces based on thermal stratification. For this embodiment, the specific implementation steps are as follows:

[0107] Step S1: Set the calculation period and define the initial values of the environmental analysis parameters; the initial values of the environmental analysis parameters include the interlayer temperature distribution T of the central block a,m(0) , the interlayer temperature distribution T of the air-conditioned area b,m(0) , the inner wall surface temperature T of the roof of the central space r(0) , and the inner wall surface temperature T of the ground of the central space f(0) ; the building operation parameters and the basic information of the atrium space in this embodiment are shown in Table 1.

[0108] Table 1: Building operation parameters and basic information of the atrium space in the embodiment

[0109]

[0110] Set the calculation period as the building operation period (10:00 - 22:00) on the typical meteorological day (July 22nd) in summer in Hangzhou, Zhejiang Province, and use the typical meteorological data of this day (outdoor hourly dry-bulb air temperature T e , outdoor hourly solar direct radiation intensity q solar ) as the calculation input conditions, as shown in Table 2.

[0111] According to the actual size of the central space, establish a proportional model in the DeST software and set the materials of each enclosure structure, and simulate the indoor hourly direct radiation q dir passing through the window and the diffuse radiation q dif based on the given meteorological parameters, and at the same time as the calculation input conditions, where the indoor direct radiation passing through the window mainly acts on the ground, and the simulation results are shown in Table 2.

[0112] Table 2: Calculation input conditions from 10:00 to 22:00 on July 22 of the embodiment

[0113]

[0114] Step S2: According to the interlayer temperature distribution of the central block and the air-conditioning area at the current moment, obtain the horizontal air convection mass flow rate between the current air-conditioning area and the central block, and the air flow deflection degree of each layer of the air-conditioning area;

[0115] Step S2 specifically includes the following steps:

[0116] Step S2.1: First, according to the interlayer temperature distribution T of the central block a,m(n) and the interlayer temperature distribution T of the air-conditioning area b,m(n) Process according to the following formula to obtain the horizontal air convection mass flow rate M between each layer of the air-conditioning area and the central block ab,m(n) :

[0117]

[0118] T ab,m(n) =(T a,m(n) +T b,m(n) ) / 2

[0119] In the formula, M ab,m(n) represents the air convection mass flow rate between the mth-layer air-conditioning area and the mth-layer central block at the nth moment; ρ represents the air density; C d represents the dimensionless correction coefficient for the convection mass flow rate considering viscous forces, usually taking a value of 0.5 to 0.7; C a represents the cross-sectional perimeter of the central block; T a,m(n) represents the interlayer temperature distribution of the mth-layer central block at the nth moment; T b,m(n) represents the interlayer temperature distribution of the mth-layer air-conditioning area at the nth moment; T ab,m(n) represents the mixed temperature of the mth-layer air-conditioning area and the mth-layer central block at the nth moment; g represents the acceleration due to gravity; h b,m represents the height of the air contact surface between the mth-layer air-conditioning area and the mth-layer central block, that is, the size of the contact surface between the mth-layer air-conditioning area and the central block in the vertical direction;

[0120] Step S2.2: Then, process according to the following formula to obtain the air flow deflection degree D of each layer of the air-conditioning area a,m(n) :

[0121]

[0122] In the formula, D a,m(n) represents the dimensionless air flow deflection degree of the convective overflow air flow in the (m - 1)th-layer air-conditioning area in the mth-layer air-conditioning area at the nth moment, D a,1(n) =0; hbn,m The pressure neutral plane height, h, representing the air contact surface height between the air-conditioning area on the mth floor and the central block on the mth floor bn,m = 1 / 3 to 1 / 2h b,m ;

[0123] Step S2.3: Judge the air flow deflection degree D a,m(n) in the air-conditioning area:

[0124] If the air flow deflection degree D a,m(n) in the air-conditioning area is less than the preset critical threshold, and the critical threshold is generally taken as 0.255, it indicates that the convective overflow air flow in the air-conditioning area on the (m - 1)th floor flows into the air-conditioning area on the mth floor at time n;

[0125] Otherwise, it indicates that the convective overflow air flow in the air-conditioning area on the (m - 1)th floor does not flow into the air-conditioning area on the mth floor at time n, and the convective overflow air flow in the air-conditioning area on the (m - 1)th floor continues to flow vertically along the original path.

[0126] In different seasons, the sorting method of the air-conditioning areas is different: in summer, the sorting method of the air-conditioning areas is from top to bottom, that is, the top floor is the 1st floor and the bottom floor is the Mth floor; conversely, in winter working conditions, the bottom floor is the 1st floor and the top floor is the Mth floor.

[0127] Step S3: Obtain the interlayer temperature distribution of the central block and the air-conditioning area at the next moment based on the inner wall surface temperatures of the central space roof and the ground at the current moment, and the air flow deflection degree in the air-conditioning area;

[0128] Specifically, step S3 is as follows:

[0129] Step S3.1: First, according to the horizontal convective mass flow rate M ab,m(n) of the air at the current moment n, and the inner wall surface temperatures of the central space roof and the ground, obtain the interlayer temperature distribution T a,m(n+1) of the central block at the next moment n + 1 according to the following formula:

[0130] M a,m-1(n) -M a,m(n) -M ab,m(n) +M in,m(n) = 0

[0131] c p M a,m-1(n) T a,m-1(n+1) -c p M a,m(n) T a,m(n+1) -c p M ab,m(n) T a,m(n+1) +C B A a (T a,m-1(n+1) -T a,m(n+1) )

[0132] -C B A a (T a,m(n+1) -T a,m+1(n+1) )+h r A r (T r(n) -T a,1(n+1) )+h f A f (T f(n) -T b,M(n) )+c p M in,m(n) T ab,M(n) =0 where M a,m(n) represents the mass flow rate of the central block in the m-th layer flowing vertically into the central block in the (m + 1)-th layer at time n, M a,0(n) =0; M in,m(n) represents the air mass flow rate flowing into the central block in the air-conditioned area at time n, M in,m(n) is formed by the convective overflow airflows converging in the air-conditioned areas of each layer and only appears in the M-th layer. For the remaining floors, M in,m(n) has a value of 0; c p represents the specific heat capacity of air; C B represents the convective heat transfer coefficient due to the vertical temperature difference between adjacent central blocks, usually taking a value of 2.3; A a represents the air contact area between adjacent central blocks; A r represents the inner wall area of the roof of the central space; A f represents the inner wall area of the ground of the central space; h r represents the convective heat transfer coefficient between the roof of the central space and the air in the topmost central block; h f represents the convective heat transfer coefficient between the ground of the central space and the air in the bottommost central block; T r(n) represents the inner wall temperature of the roof of the central space at time n; T f(n) represents the inner wall temperature of the ground of the central space at time n; M represents the total number of floors of the air-conditioned area / central block;

[0133] Due to the density difference, the convective overflow airflows in the air-conditioned areas of each floor usually flow vertically after overflow. Therefore, it is regarded as the air flow interlayer area between the central space and the surrounding air-conditioned areas. After judging whether the airflows are deflected at each floor in step S2, it is necessary to write the heat conservation equation based on their actual flow states at time n and calculate the vertical temperature distribution of the equation at time n, that is, T c,m(n) data set;

[0134] Step S3.2: Next, according to the air flow deflection degree of each layer of air conditioning areas, the temperature distribution of each layer of contact blocks is obtained by processing according to the following formula. The contact block represents the area where the air in the air conditioning area and the central block contact each other:

[0135] c p M ab,m(n) T a,m(n+1) +c p M ba,m(n) T b,m(n) +c p M c,m-1(n) T c,m-1(n+1) -c p M c,m(n) T c,m(n+1)

[0136] -c p M cb,m(n) T c,m(n+1) -c p M in,m(n) T c,M(n+1) =0

[0137] M ba,m(n) =M ab,m(n)

[0138] Among them, T c,m(n+1) represents the air temperature distribution of the contact block on the m-th layer at the (n + 1)-th moment; M ba,m(n) represents the convective overflow mass flow rate of the air conditioning area on the m-th layer at the n-th moment; M c,m(n) represents the mass flow rate flowing from the contact block on the m-th layer to the contact block on the (m + 1)-th layer at the n-th moment; M cb,m(n) represents the mass flow rate flowing from the contact block on the m-th layer to the air conditioning area on the m-th layer at the n-th moment;

[0139] In the above formula, the mass flow rate M of the contact block flowing to the air conditioning area cb,m(n) takes values as follows:

[0140] If the convective overflow air flow in the air conditioning area on the (m - 1)-th layer at the n-th moment flows into the air conditioning area on the m-th layer, then M cb,m(n) =M ab,m(n) +M c,m-1(n) ;

[0141] If the convective overflow air flow in the air conditioning area on the (m - 1)-th layer at the n-th moment does not flow into the air conditioning area on the m-th layer, then M cb,m(n) =M ab,m(n) ;

[0142] Step S3.3: Then, according to the temperature distribution of the contact block, the inter-layer temperature distribution T of the air conditioning area at the next moment (n + 1) is obtained according to the following formula b,m(n+1) :

[0143] cp M cb,m(n) T c,m(n+1) +c p M s,m(n) T s -c p M ab,m(n) T b,m(n+1) -c p M cb,m(n) T b,m(n+1) = 0

[0144] M s,m(n) = M ab,m(n)

[0145] where M s,m(n) represents the supplementary air flow mass flow of the air supply of the air conditioner in the m - th floor air - conditioned area at the n - th moment to the air - conditioned area of this floor; T s represents the set temperature of the air - conditioned area.

[0146] Step S4: Construct the total heat balance equations. Based on the total heat balance equation and the inter - layer temperature distribution of the central block and the air - conditioned areas in Step S3, obtain the inner wall surface temperatures of the roof and the ground of the central space at the next moment. The specific steps of Step S4 are as follows:

[0147] Step S4.1: First, construct a rectangular - shaped closed enclosure structure around the central space. The six enclosure panels of the enclosure structure are respectively set at the six boundaries of the central space, and the central space is rectangular - shaped. Take the two enclosure panels at the top and bottom of the enclosure structure as two enclosure units respectively, and evenly divide the four enclosure panels around the enclosure structure into M enclosure units along the vertical direction. Therefore, a total of 4M + 2 enclosure units are divided. Then, use a division plane perpendicular to the thickness direction of the enclosure unit to evenly divide the enclosure unit, so that the enclosure unit is divided into multiple discrete layer structures with uniform distribution of thermal property parameters, and take all the division planes, the inner wall surfaces and the outer wall surfaces of the enclosure unit as the discrete surfaces of the enclosure unit;

[0148] The inner wall surface and the outer wall surface of the enclosure unit are respectively two wall surfaces symmetrically distributed along the thickness direction of the enclosure unit; the discrete surfaces are counted from the inner side to the outer side of the enclosure unit. The inner wall surface of the enclosure unit is used as the first - layer discrete surface, and the outer wall surface of the enclosure unit is used as the K - th discrete surface, where K is the total number of discrete surfaces;

[0149] Obtain the heat balance equations of the inner wall surface, the division plane and the outer wall surface of the enclosure unit according to the following formula:

[0150] Inner wall surface:

[0151]

[0152] Division plane:

[0153]

[0154] Outer wall surface:

[0155]

[0156] where: τ represents the calculated time step, i.e., the difference between the nth moment and the (n - 1)th moment; c p,k(i) represents the specific heat capacity of the material of the kth discrete surface in the ith enclosure unit; ρ k(i) represents the material density of the kth discrete surface in the ith enclosure unit; Δx k(i) represents the thickness of the kth discrete surface in the ith enclosure unit. If the discrete surface has only one adjacent discrete layer, the thickness of the discrete surface is equal to half of the thickness of the discrete layer structure adjacent to the discrete surface; if the discrete surface has two adjacent discrete layers, the thickness of the discrete surface is equal to the average value of the thicknesses of the two discrete layer structures adjacent to the discrete surface; t k(i) represents the temperature of the kth discrete surface in the ith enclosure unit; h k(i) represents the surface convective heat transfer coefficient of the kth discrete surface in the ith enclosure unit; t a,k(i) represents the air temperature adjacent to the surface of the kth discrete surface in the ith enclosure unit; K k(i) represents the thermal conductivity of the material of the kth discrete surface in the ith enclosure unit; hr j,k(i) represents the surface long-wave radiation heat transfer coefficient of the kth discrete surface in the ith enclosure unit by the jth enclosure unit; t j,k(i) represents the surface temperature of the kth discrete surface in the ith enclosure unit by the jth enclosure unit; q rad,k(i) represents the radiant heat obtained by the surface of the kth discrete surface in the ith enclosure unit; K represents the total number of discrete surfaces in the ith enclosure unit;

[0157] The above surface long-wave radiation heat transfer coefficient hr j,k(i) is obtained by the following formula:

[0158] hr j,k(i) = G k(i),j · ε k(i) · σ · (t k(i) 2 + t k(j) 2 )(t k(i) + t k(j) )

[0159] where, G k,j(i) represents the radiation absorption coefficient of the kth discrete surface in the ith enclosure unit by the jth enclosure unit; ε k(i) represents the radiation emissivity of the kth discrete surface in the ith enclosure unit; σ represents the blackbody radiation constant, with a value of 5.67e-8; tk(j) Represents the temperature of the k-th discrete surface in the j-th enclosure unit;

[0160] Step S4.2: Construct the total heat balance equation system composed of the discrete surfaces of all enclosure units in the central space:

[0161]

[0162] Among them, C represents the total heat storage capacity matrix under the unit temperature change rate; T represents the total temperature matrix; A represents the total heat transfer relationship matrix; B represents the total heat disturbance parameter action matrix; u(n) represents the heat disturbance vector at the n-th moment related to the heat process; Represents the differential matrix obtained by differentiating the temperature variables in the total temperature matrix T;

[0163] In the above formula, the heat disturbance vector u(n) is determined by the interlayer temperature distribution T a,m(n) of the central block and the interlayer temperature distribution T b,m(n) of the air-conditioned area, and the expression of the heat disturbance vector u(n) is as follows:

[0164] u(n) = [T e(n) , T ug(n) , T a(n) , T b(n) , q solar(n) , q dir(n) , q dif(n) , q indoor(n) T

[0165] When it is winter, T a(n) = [T a,1(n) , T a,2(n) ,..., T a,M(n)

[0166] When it is summer, T a(n) = [T a,M(n) , T a,M-1(n) ,..., T a,1(n)

[0167] When it is winter, T b(n) = [T b,1(n) , T b,2(n) ,..., T b,M(n)

[0168] When it is summer, T b(n) = [T b,M(n) , T b,M-1(n) ,…, T b,1(n)

[0169] In the formula, T e(n) represents the outdoor air temperature at the n-th moment; T​​​​​ug(n) Denotes the basement air temperature at time n; T a(n) Denotes the dataset of the interlayer temperature distribution in the central block; T b(n) Denotes the dataset of the interlayer temperature distribution in the air-conditioned area; q solar(n) Denotes the net solar radiation intensity outdoors at time n; q dir(n) Denotes the direct solar radiation intensity through the window indoors at time n; q dif(n) Denotes the diffuse solar radiation intensity through the window indoors at time n; q indoor(n) Denotes the heat generation amount of indoor heat sources at time n.

[0170] In the said step S4.2, the expression of the total heat storage capacity matrix C is as follows:

[0171]

[0172] Wherein, C i Denotes the heat storage capacity matrix of the i-th enclosure unit, M denotes the total number of floors in the air-conditioned area; c p,k(i) Denotes the specific heat capacity of the material of the k-th discrete surface in the i-th enclosure unit; ρ k(i) Denotes the material density of the k-th discrete surface in the i-th enclosure unit; Δx k(i) Denotes the thickness of the k-th discrete surface in the i-th enclosure unit; S i Denotes the surface area of the i-th enclosure unit;

[0173] In step S4.2, the expression of the total heat transfer relationship matrix A is as follows:

[0174]

[0175] Wherein, A i Denotes the heat transfer relationship matrix of the i-th enclosure unit; A LWR,i,j Denotes the long-wave radiation heat transfer matrix between the inner surfaces of the i-th and j-th enclosure units of the K×K order; h k(i) Denotes the surface convective heat transfer coefficient of the k-th discrete surface in the i-th enclosure unit; K k(i) Denotes the material thermal conductivity of the k-th discrete surface in the i-th enclosure unit; hr j,k(i) Denotes the surface long-wave radiation heat transfer coefficient of the j-th enclosure unit to the k-th discrete surface in the i-th enclosure unit; hr i,j Denotes the radiation heat transfer coefficient of the j-th enclosure unit to the i-th enclosure unit;

[0176] In step S4.2, the expression of the total heat disturbance parameter action matrix B is as follows:

[0177] B = [B1, B2, …, B i , …, B 4M+2 ​T

[0178]

[0179] In the formula: B i represents the heat disturbance parameter action matrix of the i-th enclosure unit of order K×(2M + 6); k dir,i represents the proportion of direct solar radiation passing through the window received by the inner wall surface of the i-th enclosure unit; k dif,i represents the proportion of diffuse solar radiation passing through the window received by the inner surface of the i-th enclosure unit; k indoor,i represents the proportion of heat generated by indoor heat sources received by the inner surface of the i-th enclosure unit. Among them, the outdoor air temperature and outdoor solar radiation directly act on the roof enclosure structure. When the roof is made of transparent material, the solar radiation entering the room will also act on the ground or other indoor wall surfaces.

[0180] The heat disturbance parameter action matrix B i can be split into four parts for representation:

[0181] B i = [B i,1 , B i,2 , B i,3 , B i,4

[0182]

[0183] Among them, the number of columns of matrix B i,2 and matrix B i,3 is both M columns.

[0184] Step S4.3, using the heat disturbance vector u(n) at the current time n, obtain the inner wall surface temperature T r(n+1) of the roof in the central space at the next time n + 1 f(n+1) and the inner wall surface temperature T

[0185] of the ground in the central space.

[0186] In step S4.3, based on the heat disturbance vector u(n), the method for obtaining the inner wall surface temperatures of the roof and ground in the central space is as follows: r,f(n) :

[0187] T r,f(n) = [T r(n) , T f(n) = DT (n)

[0188]

[0189] ​where τ represents the calculated time step, i.e., the difference between the nth moment and the (n - 1)th moment; T r,f(n) represents the inner wall surface temperature distribution of the central space at the nth moment; Q represents the transition matrix; P represents an invertible matrix composed of the eigenvectors of the transition matrix Q; Λ represents a diagonal matrix with the eigenvalues of the transition matrix Q as diagonal elements; e represents the natural number; ξ represents the time variable; D represents the intermediate matrix, and the number of rows of the intermediate matrix D is the total number of all discrete surfaces in the central space; the number of columns is the total number of all elements in the heat disturbance vector u(n).

[0190] Step S5: Based on the interlayer temperature distribution of the air-conditioned area at the current moment, obtain the air-conditioning load of the air-conditioned area at this moment; Step S5 is specifically as follows:

[0191] According to the interlayer temperature distribution of the air-conditioned area, the air-conditioning load Q at the current moment n is obtained by processing according to the following formula ffb,m(n) :

[0192] Q ffb,m(n) = c p ·M cb,m(n) ·|T s,m(n) - T b,m(n) |

[0193] where Q ffb,m(n) represents the air-conditioning load flowing from the central block of the mth layer to the air-conditioned area of the ith layer through convective heat transfer at the nth moment; M cb,m(n) represents the mass flow rate of the central block of the mth layer flowing to the air-conditioned area of the mth layer at the nth moment; T s,m(n) represents the set temperature of the air-conditioned area of the ith layer at the nth moment; T b,m(n) represents the air temperature of the air-conditioned area of the ith layer at the nth moment.

[0194] Based on the convective flow distribution and air temperature distribution at each moment, the dynamic load distribution within the calculation period can be obtained, which is mainly used for dynamic prediction of the convective heat transfer load from the non-enclosed tall space around to the surrounding air-conditioned areas.

[0195] Steps S2 to S5 constitute a complete air-conditioning load prediction process at one moment. Continuously update the moment of air-conditioning operation, update the moment n to n + 1 each time, and repeat steps S2 to S5 multiple times to obtain the air-conditioning loads of the air-conditioned areas at different moments, thereby realizing the prediction of the air-conditioning loads of the air-conditioned areas around the central space during the air-conditioning operation process.

[0196] During the set calculation period, the prediction results of the convective heat transfer dynamic load from the non-enclosed tall space around to the surrounding air-conditioned areas in this embodiment are shown in Table 3.

[0197] Table 3: Convective heat transfer dynamic load distribution from the non-enclosed tall space to the surrounding air-conditioned areas in the embodiment (unit: W / m2 )

[0198]

[0199]

[0200] In summary, a dynamic air-conditioning load prediction method for non-enclosed tall spaces based on thermal stratification in this embodiment clarifies the air heat transfer and mass transfer mechanism between non-enclosed tall spaces and surrounding multi-layer air-conditioning areas. Furthermore, based on the mass and heat conservation equations, the vertical temperature distribution and convective heat transfer amount between the space body and the surrounding air-conditioning areas are solved, and the dynamic calculation of air temperature and wall temperature is realized by combining the state space method. Finally, the prediction result of the convective heat transfer dynamic load from the non-enclosed tall space to the surrounding air-conditioning areas is obtained by setting the convective flow rate and air temperature within the calculation period. Compared with the traditional load calculation method for tall spaces, it solves problems such as the load caused by the convective heat transfer from this type of space to the surrounding air-conditioning areas not being considered in engineering applications, inaccurate load calculation due to the thermal stratification not being considered, and the impact brought by only calculating the static load and ignoring the dynamic changes of the external environment.

[0201] It should be understood that the above embodiments are only used to illustrate the specific implementation manners of the present invention, enabling those skilled in the art to understand or implement the present invention, and the present invention is not limited thereto. Any modifications, equivalent replacements, and improvements made within the scope of the purpose and claims of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dynamic air-conditioning load prediction method for non-enclosed tall spaces based on thermal stratification, characterized in that Including the following steps: Step S1: First, define the initial values of the environmental analysis parameters; the environmental analysis parameters include the interlayer temperature distribution of the central block and the air-conditioning area, and the inner wall surface temperatures of the roof and the ground of the central space; Step S2: According to the interlayer temperature distribution of the central block and the air-conditioning area at the current moment, obtain the horizontal convective mass flow rate of the air between the current air-conditioning area and the central block, and the airflow deflection degree of each layer of the air-conditioning area; Step S3: Based on the inner wall surface temperatures of the roof and the ground of the central space at the current moment, and the airflow deflection degree of the air-conditioning area, obtain the interlayer temperature distribution of the central block and the air-conditioning area at the next moment; Step S4: Construct the total heat balance equations, and based on the total heat balance equations and the interlayer temperature distribution of the central block and the air-conditioning area in Step S3, obtain the inner wall surface temperatures of the roof and the ground of the central space at the next moment; Step S5: Based on the interlayer temperature distribution of the air-conditioning area at the current moment, obtain the air-conditioning load of the air-conditioning area at that moment; Steps S2 to S5 constitute a complete air-conditioning load prediction process at one moment. Continuously update the moment of air-conditioning operation, and repeat Steps S2 to S5 multiple times to obtain the air-conditioning loads of the air-conditioning areas at different moments, so as to realize the prediction of the air-conditioning loads of the air-conditioning areas around the central space during the air-conditioning operation process.

2. The dynamic air conditioning load prediction method for non - enclosed tall spaces based on thermal stratification according to claim 1, wherein: The specific content of Step S2 is as follows: Step S2.1: First, according to the interlayer temperature distribution T of the central block a,m(n) and the interlayer temperature distribution T of the air-conditioning area b,m(n) the horizontal convective mass flow rate M of the air between the air-conditioning area and the central block of each layer is obtained by processing according to the following formula ab,m(n) : T ab,m(n) = (T a,m(n) + T b,m(n) ) / 2 where M ab,m(n) represents the air convection mass flow rate between the m-th floor air-conditioned area and the m-th floor central block at the n-th moment; ρ represents the air density; C d represents the dimensionless correction coefficient of the convection mass flow rate considering viscous forces; C a represents the cross-sectional perimeter of the central block; T a,m(n) represents the interlayer temperature distribution of the m-th floor central block at the n-th moment; T b,m(n) represents the interlayer temperature distribution of the m-th floor air-conditioned area at the n-th moment; T ab,m(n) represents the mixed temperature of the m-th floor air-conditioned area and the m-th floor central block at the n-th moment; g represents the acceleration due to gravity; h b,m represents the height of the air contact surface between the m-th floor air-conditioned area and the m-th floor central block; Step S2.

2. Then, the airflow deflection degree D of each air conditioning zone is obtained according to the following formula a,m(n) :[[]]END]] where D a,m(n) represents the dimensionless airflow deflection degree of the convective overflow airflow in the air conditioning zone of the (m - 1)-th layer at the n-th moment in the air conditioning zone of the m-th layer; h bn,m represents the pressure neutral surface height of the air contact surface height between the air conditioning zone of the m-th layer and the central block of the m-th layer; Step S2.3, judge the air flow deflection degree D of the air conditioning area a,m(n) for judgment: If the air flow deflection degree D in the air conditioning zone a,m(n) is less than the preset critical threshold, it indicates that the convective overflow air flow in the air conditioning zone of the (m - 1)-th layer flows into the air conditioning zone of the m-th layer at the n-th moment; Otherwise, it indicates that the convective overflow air flow in the air-conditioning area of the (m - 1)-th layer at the n-th moment does not flow into the air-conditioning area of the m-th layer.

3. A dynamic air conditioning load prediction method for non - enclosed tall spaces based on thermal stratification according to claim 1, characterized in that: The specific content of Step S3 is as follows: Step S3.

1. First, according to the air horizontal convective mass flow rate M at the current moment n ab,m(n) , and the inner wall surface temperatures of the central space roof and the ground, obtain the interlayer temperature distribution T of the central block at the next moment n + 1 according to the following formula a,m(n+1) : M a,m-1(n) -M a,m(n) -M ab,m(n) +M in,m(n) = 0 c p M a,m-1(n) T a,m-1(n+1) -c p M a,m(n) T a,m(n+1) -c p M ab,m(n) T a,m(n+1) +C B A a (T a,m-1(n+1) -T a,m(n+1) ) -C B A a (T a,m(n+1) -T a,m+1(n+1) ) + h r A r (T r(n) -T a,1(n+1) ) + h f A f (T f(n) -T b,M(n) ) + c p M in,m(n) T ab,M(n) = 0 where M a,m(n) represents the mass flow rate of the central block in the m-th layer flowing vertically into the central block in the (m + 1)-th layer at time n; M in,m(n) represents the mass flow rate of air flowing into the central block in the air-conditioned area at time n; c p represents the specific heat capacity of air; C B represents the convective heat transfer coefficient due to the vertical temperature difference between adjacent central blocks; A a represents the air contact area between adjacent central blocks; A r represents the inner wall area of the roof of the central space; A f represents the inner wall area of the ground of the central space; h r represents the convective heat transfer coefficient between the roof of the central space and the air in the topmost central block; h f represents the convective heat transfer coefficient between the ground of the central space and the air in the bottommost central block; T r(n) represents the inner wall temperature of the roof of the central space at time n; T f(n) represents the inner wall temperature of the ground of the central space at time n; M represents the total number of layers of the air-conditioned area / central block; Step S3.2: Then, according to the airflow deflection degrees of each layer of the air-conditioning area, process them according to the following formula to obtain the temperature distribution of each layer of contact blocks: c p M ab,m(n) T a,m(n+1) +c p M ba,m(n) T b,m(n) +c p M c,m-1(n) T c,m-1(n+1) -c p M c,m(n) T c,m(n+1) -c p M cb,m(n) T c,m(n+1) -c p M in,m(n) T c,M(n+1) = 0 M ba,m(n) = M ab,m(n) Among them, T c,m(n+1) represents the air temperature distribution of the contact block in the m-th layer at the (n + 1)-th moment; M ba,m(n) represents the convective overflow mass flow rate of the air-conditioning area in the m-th layer at the n-th moment; M c,m(n) represents the mass flow rate flowing from the contact block in the m-th layer to the contact block in the (m + 1)-th layer at the n-th moment; M cb,m(n) represents the mass flow rate flowing from the contact block in the m-th layer to the air-conditioning area in the m-th layer at the n-th moment; In the above formula, the mass flow rate M of the contact block flowing into the air-conditioning area cb,m(n) is obtained as follows: If the convective overflow air current in the air conditioning area of the (m - 1)-th layer flows into the air conditioning area of the m-th layer at time n, then M cb,m(n) = M ab,m(n) + M c,m-1(n) ; If the convective overflow air flow in the air-conditioning zone on the (m - 1)-th floor at the n-th moment does not flow into the air-conditioning zone on the m-th floor, then M cb,m(n) = M ab,m(n) ; Step S3.

3. Then, according to the temperature distribution of the contact block, the interlayer temperature distribution T of the air-conditioned area at the next moment n+1 is obtained according to the following formula b,m(n+1) : c p M cb,m(n) T c,m(n+1) +c p M s,m(n) T s -c p M ab,m(n) T b,m(n+1) -c p M cb,m(n) T b,m(n+1) =0 M s,m(n) = M ab,m(n) Among them, M s,m(n) represents the supplementary air mass flow rate of the air supply of the air conditioner in the m-th air-conditioned area at the n-th moment to the air-conditioned area on the same floor; T s represents the set temperature of the air-conditioned area.

4. A dynamic air-conditioning load prediction method for non-enclosed tall spaces based on thermal stratification according to claim 1, characterized in that: The specific content of Step S4 is as follows: Step S4.1: First, construct a rectangular closed enclosure structure around the central space. The six enclosure panels of the enclosure structure are respectively arranged at the six boundaries of the central space; regard the two enclosure panels at the top and bottom of the enclosure structure as two enclosure units respectively, evenly divide the four enclosure panels around the enclosure structure into M enclosure units along the vertical direction, then use a division plane perpendicular to the thickness direction of the enclosure unit to evenly divide the enclosure unit, and regard all division planes, the inner wall surfaces and the outer wall surfaces of the enclosure unit as the discrete surfaces of the enclosure unit; Step S4.2: Construct the total heat balance equations composed of all the discrete surfaces of the enclosure units in the central space: Among them, C represents the total heat storage capacity matrix under the unit temperature change rate; T represents the total temperature matrix; A represents the total heat transfer relationship matrix; B represents the total heat disturbance parameter action matrix; u(n) represents the heat disturbance vector related to the heat process at the nth moment; represents the differential matrix obtained by differentiating the temperature variables in the total temperature matrix T; In the above formula, the thermal disturbance vector u(n) is determined by the interlayer temperature distribution T of the central block a,m(n) and the interlayer temperature distribution T of the air-conditioned area b,m(n) and the expression of the thermal disturbance vector u(n) is as follows: u(n) = [T e(n) , T ug(n) , T a(n) , T b(n) , q solar(n) , q dir(n) , q dif(n) , q indoor(n) T ​ When in winter time, T a(n) = [T a,1(n) , T a,2(n) , …, T a,M(n) ​ When it is summer time, T a(n) =[T a,M(n) , T a,M-1(n) , …, T a,1(n) ​ When in winter time, T b(n) = [T b,1(n) , T b,2(n) , …, T b,M(n) ​ When in summer time, T b(n) =[T b,M(n) , T b,M-1(n) , …, T b,1(n) ​ where, T e(n) represents the outdoor air temperature at time n; T ug(n) represents the basement air temperature at time n; T a(n) represents the dataset of the interlayer temperature distribution in the central block; T b(n) represents the dataset of the interlayer temperature distribution in the air-conditioned area; q solar(n) represents the outdoor net solar radiation intensity at time n; q dir(n) represents the indoor direct solar radiation intensity through the window at time n; q dif(n) represents the indoor diffuse solar radiation intensity through the window at time n; q indoor(n) represents the heat generation of indoor heat sources at time n; Step S4.3: Using the thermal disturbance vector u(n) at the current moment n, obtain the inner wall surface temperature T of the roof of the central space at the next moment n + 1 r(n+1) and the inner wall surface temperature T of the ground of the central space f(n+1) .

5. A dynamic air-conditioning load prediction method for non-enclosed tall spaces based on thermal stratification according to claim 4, characterized in that: In Step S4.2, the expression of the total heat storage capacity matrix C is as follows: Among them, C i represents the heat storage capacity matrix of the i-th enclosure unit, M represents the total number of floors in the air-conditioned area; c p,k(i) represents the specific heat capacity of the material of the k-th discrete surface in the i-th enclosure unit; ρ k(i) represents the material density of the k-th discrete surface in the i-th enclosure unit; Δx k(i) represents the thickness of the k-th discrete surface in the i-th enclosure unit; S i represents the surface area of the i-th enclosure unit. In Step S4.2, the expression of the total heat transfer relationship matrix A is as follows: Among them, A i represents the heat transfer relationship matrix of the i-th enclosure unit; A LWR,i,j represents the long-wave radiation heat transfer matrix between the inner surfaces of the i-th and j-th enclosure units of order K×K; h k(i) represents the surface convective heat transfer coefficient of the k-th discrete surface in the i-th enclosure unit; K k(i) represents the material thermal conductivity of the k-th discrete surface in the i-th enclosure unit; hr j,k(i) represents the surface long-wave radiation heat transfer coefficient of the j-th enclosure unit to the k-th discrete surface in the i-th enclosure unit; hr i,j represents the radiation heat transfer coefficient of the j-th enclosure unit to the i-th enclosure unit; In Step S4.2, the expression of the total heat disturbance parameter action matrix B is as follows: B = [B1, B2, …, B i , …, B 4M+2 T ​ Where: B i represents the thermal disturbance parameter action matrix of the i-th enclosure unit of order K×(2M + 6); k dir,i represents the proportion of direct solar radiation received by the inner wall surface of the i-th enclosure unit through the window; k dif,i represents the proportion of diffuse solar radiation received by the inner surface of the i-th enclosure unit through the window; k indoor,i represents the proportion of heat generated by indoor heat sources received by the inner surface of the i-th enclosure unit.

6. A dynamic air conditioning load prediction method for non - enclosed high - rise spaces based on thermal stratification according to claim 4, characterized in that: In Step S4.3, the method for obtaining the inner wall surface temperatures of the roof and the ground of the central space based on the heat disturbance vector u(n) is as follows: According to the total heat storage capacity matrix C and the heat disturbance vector u(n), the inner wall surface temperature distribution T of the central space is obtained according to the following formula r,f(n) : T r,f(n) = [T r(n) , T f(n) = DT (n) where τ represents the calculated time step, i.e., the difference between the n-th moment and the (n - 1)-th moment; T r,f(n) represents the inner wall surface temperature distribution of the central space at the n-th moment; Q represents the transition matrix; P represents an invertible matrix composed of the eigenvectors of the transition matrix Q; Λ represents a diagonal matrix with the eigenvalues of the transition matrix Q as diagonal elements; e represents the natural number; ξ represents the time variable; D represents an intermediate matrix, and the number of rows of the intermediate matrix D is the total number of all discrete surfaces in the central space; the number of columns is the total number of all elements in the thermal perturbation vector u(n).

7. A dynamic air conditioning load prediction method for non - enclosed tall spaces based on thermal stratification according to claim 1, characterized in that: The specific content of Step S5 is as follows: According to the inter - layer temperature distribution in the air - conditioned area, the air - conditioning load Q at the current moment n is obtained by processing according to the following formula ffb,m(n) : Q ffb,m(n) = c p · M cb,m(n) · |T s,m(n) - T b,m(n) | Among them, Q ffb,m(n) represents the air conditioning load amount that the central block of the m-th layer flows to the air conditioning area of the i-th layer through convective heat transfer at the n-th moment; M cb,m(n) represents the mass flow rate that the central block of the m-th layer flows to the air conditioning area of the m-th layer at the n-th moment; T s,m(n) represents the set temperature of the air conditioning area of the i-th layer at the n-th moment; T b,m(n) represents the air temperature of the air conditioning area of the i-th layer at the n-th moment.

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