A non-uniform heat transfer evaluation method for dry-joint assembled exterior walls

Abstract

The present invention discloses a method for evaluating the non-uniform heat transfer of dry-jointed assembled exterior walls, comprising the following steps: S1: focusing on the joints, testing or simulating the heat transfer behavior of dry-jointed assembled exterior walls to obtain the temperature distribution on the interior wall surface; S2: determining the impact range of the non-uniform heat transfer caused by the dry-jointed wall panel joints based on the temperature distribution on the interior wall surface; S3: calculating the cumulative temperature difference ratio T' on the interior wall surface; and S4: comparing the cumulative temperature difference ratio T' on the interior wall surface with 0.8 to evaluate the non-uniform heat transfer of the prefabricated building exterior wall. The present invention can quantitatively evaluate the impact of the joints on the heat transfer non-uniformity of the prefabricated building exterior walls constructed using dry-jointing methods.

Description

Technical Field

[0001] The present invention relates to the technical field of building thermal engineering and building energy conservation, and in particular to a non-uniform heat transfer evaluation method for dry-type connection assembly exterior walls. Background Art

[0002] Prefabricated buildings are an important way to achieve building industrialization and are in line with the concepts of sustainable development and a circular economy. In recent years, prefabricated buildings have been widely promoted and applied, showing a rapid and steady development trend.

[0003] The connections between prefabricated components in prefabricated buildings can be categorized as wet or dry. Dry connections are widely used during construction due to their ease of construction and high assembly efficiency, and are the future trend in prefabricated building development. When prefabricated components are dry-connected, numerous joints are created between the components, with joint widths ranging from approximately 15 to 35 mm. Currently, joints are typically treated by filling with waterproofing adhesive and insulating mortar, but their heat transfer characteristics differ significantly from those of the main structure, creating thermal bridge-like properties. This can significantly impact the uniformity and unidimensionality of heat transfer within the wall, as well as the building's energy consumption. Joints between exterior wall components in prefabricated buildings are more common and numerous than thermal bridges in traditional buildings. The uneven heat transfer caused by these joints, resulting in thermal bridges, has a significant impact on the building's thermal performance.

[0004] Currently, thermal and energy-saving calculations and designs for dry-type prefabricated walls are based on the traditional uniform wall model, ignoring the significant non-uniform heat transfer characteristics of dry-type prefabricated walls. Whether the wall conducts heat uniformly has a significant impact on heat transfer calculations and analysis, as well as the overall thermal characteristics of the wall. Therefore, selecting appropriate methods to accurately evaluate the wall's non-uniform heat transfer is of great significance to the thermal design of prefabricated buildings. Summary of the Invention

[0005] In order to overcome the above-mentioned deficiencies of the prior art, the object of the present invention is to provide a method for evaluating the non-uniform heat transfer of dry-connected assembled exterior walls, which can quantitatively evaluate the impact of the joints of the exterior walls of prefabricated buildings constructed by dry connection on the non-uniform heat transfer of the wall.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for evaluating non-uniform heat transfer in dry-joint assembled exterior walls comprises the following steps;

[0008] S1: Focusing on the joints, the temperature distribution on the inner surface of the exterior wall is obtained by testing or simulating the heat transfer law of the dry-connected assembled exterior wall;

[0009] S2: Determine the impact range of non-uniform heat transfer caused by dry-jointed wall panel joints based on the temperature distribution on the inner wall surface of the exterior wall;

[0010] S3: Calculate the cumulative temperature difference ratio T' of the inner wall surface of the exterior wall;

[0011] S4: Compare the cumulative temperature difference ratio T' between the inner and outer wall surfaces with 0.8 to evaluate the non-uniform heat transfer of the prefabricated building exterior wall.

[0012] In step S1, the temperature distribution curves at different distances from the inner surface of the wall are derived and recorded as t (x) .

[0013] In step S2, the range of influence of the non-uniform heat transfer caused by the joint is calculated as follows:

[0014] Under steady-state conditions, the temperature difference ratio ξ at any point of the enclosure structure satisfies the following formula:

[0015]

[0016] For the inner surface of the enclosure structure, the temperature difference ratios ξ1 and ξ1' at the normal location and the non-uniform heat transfer location satisfy the following formula:

[0017]

[0018]

[0019] The location of the non-uniform heat transfer area must satisfy the following formula:

[0020]

[0021] Where, t f1 is the indoor ambient temperature, ℃; t f2 is the outdoor ambient temperature, ℃; t P is the temperature of any point P on the inner surface, °C; t1 is the inner surface temperature of the normal part, °C; t'1 is the critical temperature of the surface in the area affected by non-uniform heat transfer, °C;

[0022] The critical surface temperature t'1 within the non-uniform heat transfer affected area can be obtained from equations (1) to (4), thereby determining the non-uniform heat transfer affected area.

[0023] In step S3, since the uneven heat transfer of the wall is manifested in two aspects: the distance of the thermal bridge and the temperature difference between the joint and the main body of the exterior wall, the cumulative temperature difference ratio T' is calculated by combining the influence of the two. The calculation method is shown in formula (5):

[0024]

[0025] Where, t (x)is the wall temperature distribution function, ℃; t0 is the temperature value of the main part, ℃; l is the coordinate of the area affected by non-uniform heat transfer, m; L is the coordinate of the main part, m.

[0026] The T' is the ratio of the cumulative temperature difference T in the area affected by the non-uniform heat transfer to the cumulative temperature difference T0 of the entire wall. It reflects the severity of the temperature change on both sides of the wall caused by the joint and is used to reflect the non-uniform heat transfer of the wall caused by the joint. The larger the temperature change on both sides caused by the joint, the larger T, which makes T' larger and the more non-uniform the heat transfer of the wall.

[0027] In step S4, when T'>0.8, the wall heat transfer is uneven.

[0028] Regarding step S4, there is also a method for evaluating the significance of the non-uniform heat transfer effect of the wall. This evaluation method is derived from Fourier's law, takes into account the additional heat flow caused by non-uniform heat transfer, and reflects it through the indicator "non-uniform equivalent heat transfer coefficient KT";

[0029] When there is no internal heat source in the wall, the total heat passing through the wall is Q sum The calculation is as shown in formula (6), that is, the total heat passing through the wall is composed of the heat flow of the main body and the area affected by non-uniform heat transfer:

[0030]

[0031] Thus, the average heat transfer coefficient of the wall is Formula (7):

[0032]

[0033] Then, the non-uniform equivalent heat transfer coefficient K T It can be expressed as formula (8):

[0034]

[0035] In the above formula, is the average heat transfer coefficient of the wall, W / (㎡·K); K T is the non-uniform equivalent heat transfer coefficient, W / (㎡·K); Q sum is the total heat passing through the wall, W; K P is the main heat transfer coefficient, W / (㎡·K); F P is the area of the main part of the wall, m2; F T is the area of each non-uniform heat transfer part of the wall, m2; ΔT is the temperature difference between the inner and outer surfaces of the wall, °C; A is the sum of the areas of the non-uniform heat transfer part and the main part of the wall, m2;

[0036] From the above formula, we can simplify and derive formula (9):

[0037]

[0038] Where l0 is the width of the area affected by non-uniform heat transfer, m; q (x) is a function of heat flux density, which can be obtained through Fluent simulation; F T0 is the area affected by non-uniform heat transfer, m2; h is the wall height, m; x0 and x1 are the starting and ending coordinates of the thermal bridge influence distance.

[0039] Beneficial effects of the present invention:

[0040] This paper quantitatively evaluates the uneven heat transfer caused by dry-joint exterior wall joints using the wall's cumulative temperature difference ratio, T'. Orthogonal experiments confirm that uneven heat transfer occurs when T' exceeds 0.8 for prefabricated walls. This evaluation method is unaffected by the type and construction of the prefabricated wall; the heat transfer uniformity of the wall can be determined solely by the temperature distribution of the wall's inner surface. Understanding the impact of joints on wall heat transfer uniformity can aid in improving joint construction to reduce heat loss and optimize wall thermal performance.

[0041] On the other hand, it is proposed to use the non-uniform equivalent heat transfer coefficient K T To evaluate the significance of the non-uniform heat transfer effect. In the past, when calculating the wall with thermal bridge structure, the weighted average heat transfer coefficient of the thermal bridge part and the wall main body part was used. This method cannot take the influence of the non-uniform heat transfer effect into account, and is particularly inappropriate when the non-uniform heat transfer range is too small. The non-uniform equivalent heat transfer coefficient K in the present invention is T The proposal converts the heat flux increased by the joint thermal bridge into the range of influence of non-uniform heat transfer. Although the joint size is extremely small, the heat loss generated by it can be taken into account, effectively reflecting the impact of the non-uniform heat transfer generated by it on the enclosing structure.

[0042] This invention fills the gap in the research on heat transfer of dry-connected assembled exterior walls, conducts quantitative analysis of the uneven heat transfer of assembled exterior walls, and provides an analysis method for the uneven heat transfer effect, which helps to better guide the thermal and energy-saving design of dry-connected assembled exterior walls. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a structural diagram of the joint area.

[0044] Figure 2 Schematic diagram of the inner wall temperature and heat flux distribution of the phase change thermal storage triple wall.

[0045] Figure 3 Schematic diagram of the wall temperature and heat flux distribution inside the phase change wall containing an air layer.

[0046] Figure 4 Schematic diagram of the wall temperature and heat flux distribution inside the composite Trombe wall.

[0047] Figure 5 Schematic diagram of the wall temperature and heat flux distribution inside the prefabricated sandwich wall.

[0048] Figure 6 Schematic diagram of the temperature and heat flow distribution on the inner wall of a traditional brick-concrete exterior wall.

[0049] Figure 7 Schematic diagram of the building model for energy consumption simulation.

[0050] Figure 8 Schematic diagram of the impact of thermal bridge effect of dry-connected prefabricated wall joints on building energy consumption.

[0051] Figure 9 Schematic diagram of the relationship between wall heat transfer uniformity and building energy consumption. DETAILED DESCRIPTION

[0052] The present invention will be further described in detail below with reference to the embodiments.

[0053] This example selects five dry-joint assembled exterior walls for non-uniformity evaluation and analysis. For comparison, a traditional brick-concrete building with external insulation is also selected for analysis. The structures of the six wall types are the same as in Table 4. During the heat transfer simulation, the joint width between prefabricated wall panels ranges from 15 to 30 mm in increments of 5 mm. The joints are filled with waterproof strips inside and outside. The structure is as follows: Figure 1 The width of structural columns (collectively referred to as joints) in traditional brick-concrete buildings varies from 210 to 300 mm, with increments of 30 mm. The wall dimensions in this case are 3 meters wide and 2.7 meters high.

[0054] S1. Wall heat transfer simulation:

[0055] The heat transfer of each wall is simulated by the fluid dynamics calculation software ANSYS Fluent. The basic parameters and methods of thermal calculation are determined in accordance with the "Code for Thermal Design of Civil Buildings" (GB50176-2016). In this example, the calculation parameters of outdoor air in winter in Shijiazhuang, Hebei Province are taken, and the third-class boundary conditions are used for the internal and external surface constraints of the model, which stipulates the convection heat transfer coefficient between the inner and outer surfaces of the wall and the air and the temperature of the air on the inner and outer surfaces of the wall. The low-temperature side is used to simulate the outdoor environmental conditions. The outdoor thermal calculation temperature in winter in Shijiazhuang is -5.3℃, and the convection heat transfer coefficient is 23W / (m 2 ·K), the high temperature side is used to simulate the indoor environment, the temperature is 20℃, and the convection heat transfer coefficient is 8.7W / (m 2 ·K); Except for the inner and outer surfaces, the model's boundaries are adiabatic. The temperature and heat flow distribution of each wall obtained by simulation are as follows Figure 2-Figure 6 shown.

[0056] S2. Thermal bridge impact distance of joints between walls:

[0057] For the inner surface of the maintenance structure, the area affected by the bridge must satisfy formula (4):

[0058] By this formula The critical surface temperature t1' within the non-uniform heat transfer affected area can be calculated, thereby determining the non-uniform heat transfer affected range. The results are shown in Table 1.

[0059] Table 1 The influence range of non-uniform heat transfer of each wall joint

[0060]

[0061] S3. Calculate the cumulative temperature difference ratio T' between the exterior and interior walls:

[0062] Since the uneven heat transfer of the wall is manifested in two aspects: the distance affected by the uneven heat transfer and the temperature difference and heat flow difference between the joint and the main body of the exterior wall, the cumulative temperature difference ratio T' can effectively integrate the influence of these two aspects. According to formula (5) Calculate the cumulative temperature difference ratio T'. The cumulative temperature difference ratios of each wall are shown in Table 2:

[0063] Table 2 Cumulative temperature difference ratio of each wall

[0064]

[0065] S4. Compare the cumulative temperature difference ratio T' between the exterior wall and the interior wall with 0.8 to evaluate the non-uniform heat transfer of the prefabricated building exterior wall:

[0066] As shown in Table 4, the cumulative temperature difference ratio T' of the exterior and interior walls of the four prefabricated walls in this case is greater than 0.8, indicating that the walls exhibit uneven heat transfer due to the influence of the joints. However, the cumulative temperature difference ratio T' of the exterior walls of traditional brick-concrete buildings with external insulation treatment for structural columns is around 0.4, indicating relatively uniform heat transfer.

[0067] In addition, the non-uniform equivalent heat transfer coefficient K T , and evaluate the significance of the thermal bridge effect of the exterior walls of prefabricated buildings and traditional brick-concrete buildings with different structures.

[0068] K of each wall T As shown in Table 3. Non-uniform equivalent heat transfer coefficient K T From formula (9) calculate:

[0069] Table 3 Non-uniform equivalent heat transfer coefficient K of each wall T

[0070]

[0071] From Table 3, we can see that the K T The values are greater than those of traditional brick-concrete buildings. The thermal bridge effect caused by the joints of prefabricated phase change walls containing air layers is the most significant, ranging from about 19 to 21 W / (㎡·K); the K of the joints of the exterior walls of traditional brick-concrete buildings is T The value is the smallest, and the variation range is about 4 to 5W / (㎡·K), which also shows that the external insulation structure can effectively reduce the thermal bridge effect.

[0072] In step S4, it is considered that the wall heat transfer is uneven when T'>0.8. The specific determination method is as follows:

[0073] A comprehensive orthogonal experiment was conducted on the five prefabricated wall structures shown in Table 4 below, with joint widths of 15mm, 20mm, 25mm, and 30mm, respectively. These were compared with traditional brick-concrete buildings with joint (structural column) widths of 210mm, 240mm, 270mm, and 300mm, respectively. The calculations in steps S1 to S3 determined that the critical T' value for uneven heat transfer in prefabricated exterior walls is 0.8. Therefore, if the cumulative temperature difference ratio T' on the inner wall of a prefabricated wall exceeds 0.8, the heat transfer is considered uneven; otherwise, the heat transfer is considered uniform.

[0074] Table 4 Wall structure

[0075]

[0076] In the past, when using the weighted average heat transfer coefficient to calculate the heat transfer of the wall, the influence of small-sized thermal bridges was easily underestimated. Although the joint size of the prefabricated wall using the dry connection method is very small, the thermal bridge effect it produces is more significant. T Evaluation can effectively consider the additional heat flux caused by the uneven heat transfer caused by the joints. For the exterior walls of prefabricated buildings, although the structures of various types of exterior walls are different, K T The calculation can effectively reflect the significance of the non-uniform heat transfer effect caused by the joint, and this method is simpler to calculate.

[0077] Uneven heat transfer caused by dry-joint exterior wall joints can impact overall building performance, such as energy consumption. To understand the impact of heat transfer uniformity in prefabricated walls on buildings, we next analyzed the relationship between wall heat transfer uniformity and building energy consumption. We first calculated the heat transfer coefficient of the entire wall before and after accounting for the thermal bridge effect of the joints. Using the energy simulation software Design Builder, we simulated heating energy consumption for walls with different heat transfer coefficients, thereby understanding the relationship between wall heat transfer uniformity and building energy consumption.

[0078] Formulas (10) and (11) are used to calculate the heat transfer coefficient of the wall before and after considering the non-uniform heat transfer effect of the joint. The results are shown in Table 5:

[0079]

[0080]

[0081] Where, is the average heat transfer coefficient of the wall without considering the non-uniform thermal effect of the joint, W / (㎡·K); is the average heat transfer coefficient of the wall without considering the non-uniform thermal effect of the joint, W / (㎡·K); K B is the heat transfer coefficient of the joint, W / (㎡·K); F B is the area of the wall joint, m2; F 影响区域 is the area affected by the non-uniform heat transfer caused by the joint, m2.

[0082] Table 5 Influence of non-uniform thermal effect of joints on heat transfer coefficients of each wall

[0083]

[0084] Energy consumption analysis was performed using the energy consumption simulation software Design Builder. This software can directly define the wall heat transfer coefficient. The heat transfer coefficients of six types of walls before and after considering the joint thermal bridge effect were input and heating energy consumption simulation was performed. The simulated building model is shown in the attached figure. Figure 7 The building is a small 5-story office building located in Shijiazhuang, with a construction area of 1575㎡ and a volume of 4252.5m 3 The building is 13.5 meters high, with a form factor of 0.302, a north-south window-to-wall ratio of 0.185, and an east-west window-to-wall ratio of 0.09. The winter indoor design temperature is set at 20°C, the occupant density is 0.25 (person / ㎡), the occupant activity is 120 (W / person), the equipment load is 13 (W / ㎡), and the equipment load is 12 (W / ㎡).

[0085] The influence of the non-uniform thermal effect of the joints on the energy consumption of the wall is shown in the attached figure. Figure 8 As shown in the figure, when the non-uniform thermal effect of joints is considered, the building heating energy consumption of each wall type increases. Among them, the energy consumption of traditional brick-concrete building exterior walls changes slightly before and after considering the non-uniform thermal effect, with energy consumption increasing by approximately 4 to 5 (kW h) / m2. Prefabricated walls show a larger change in energy consumption before and after considering the non-uniform thermal effect. The building energy consumption of ordinary prefabricated sandwich walls increases by approximately 15 to 25 (kW h) / m2. The increase in building heating energy consumption of the four prefabricated solar wall types is slightly greater than that of ordinary prefabricated sandwich wall buildings. Buildings using composite Trombe walls have the largest increase in energy consumption after considering the uniform thermal effect of joints, approximately 17 to 31 (kW h) / m2.

[0086] In order to more intuitively analyze the impact of uneven heat transfer of prefabricated walls on building energy consumption, the cumulative temperature difference ratio T', a parameter reflecting the uniformity of wall heat transfer, is used as the horizontal axis to analyze the relationship between wall heat transfer uniformity and building energy consumption. The relationship between wall heat transfer uniformity and building energy consumption is shown in the attached figure. Figure 9 As shown in the figure, building energy consumption increases with the increase in the cumulative temperature difference ratio T', that is, the more uneven the wall heat transfer, the greater the building heating energy consumption. Traditional brick-concrete exterior walls have relatively uniform heat transfer, and changes in their column width have no significant impact on building heating energy consumption. The building energy consumption of various prefabricated walls is significantly affected by the uniformity of the exterior wall heat transfer; the uneven heat transfer caused by each 5mm increase in joint width causes the building heating energy consumption of ordinary prefabricated walls to change by approximately 3.2% to 3.9%. Among them, the special structure of prefabricated solar walls containing air layers makes the uneven heat transfer have a particularly significant impact on energy consumption. This is especially true for phase change walls containing air layers. The uneven heat transfer caused by each 5mm change in joint width causes the building heating energy consumption of phase change walls containing air layers to change by approximately 3.2% to 6.7%.

[0087] Therefore, although the size of the joints in prefabricated building exterior walls is small, they have a significant impact on the uniform heat transfer of the wall. At the same time, the thermal bridge effect they produce cannot be ignored. Obviously, when the thermal bridge effect of the joints is not considered, the heat transfer coefficient of the wall is low, and the building heating energy consumption is underestimated. The uniformity of heat transfer in prefabricated walls affects building energy consumption. The more uneven the heat transfer, the greater the building energy consumption.

[0088] Figure 2 The heat flux and inner wall temperature distribution of the phase change thermal storage triple wall. The left side shows the heat flux distribution, and the right side shows the wall temperature distribution. Figure 3 The heat flux and inner wall temperature distribution of the phase change wall containing the air layer. The left side is the heat flux distribution and the right side is the wall temperature distribution. Figure 4 The heat flux and inner wall temperature distribution of the composite Trombe wall. The left side is the heat flux distribution and the right side is the wall temperature distribution. Figure 5 The heat flux and inner wall temperature distribution of the prefabricated sandwich wall. The left side shows the heat flux distribution, and the right side shows the wall temperature distribution. Figure 6 The heat flow and inner wall temperature distribution of the traditional brick-concrete exterior wall. The left side is the heat flow distribution and the right side is the wall temperature distribution. Figure 7 The simulated building model. Figure 8 The building energy consumption corresponding to different joint thermal bridge effects. Figure 9 This is the relationship curve between wall heat transfer uniformity and building heating energy consumption.

[0089] The glossary in the document is explained as follows:

[0090] Heat transfer law: the law of heat energy transfer in the wall caused by temperature difference. Dry-type joint wall panel joint: the gap formed between wall components when the prefabricated wall is spliced by dry connection. Non-uniform heat transfer: the heat transfer phenomenon of different intensities on the wall surface and inside the wall. Splicing seam: the connecting gap between wall components, the same as the dry-type joint wall panel joint. Normal parts and non-uniform heat transfer parts: uniform heat transfer and non-uniform heat transfer parts; thermal bridge: reinforced concrete or metal beams, columns, ribs and other parts in the enclosing structure such as exterior walls and roofs. Because these parts have strong heat transfer capacity, dense heat flow and low inner surface temperature, they are called thermal bridges. Thermal bridge impact distance: the range of non-uniform heat transfer in the wall.

[0091] In summary, the method proposed in this invention for evaluating the non-uniform heat transfer of dry-type jointed assembled exterior walls is simple and effective. The evaluation method is not affected by the type and structure of the prefabricated wall. The heat transfer uniformity of the wall can be determined by only the temperature distribution on the inner surface of the wall. In addition, the non-uniform equivalent heat transfer coefficient K is used. T This method evaluates the significance of thermal bridging effects by converting the increased heat flux from joint thermal bridges into the thermal bridge influence range. This allows for the heat loss generated by even the smallest joints, effectively reflecting the magnitude of their non-uniform thermal effects. Furthermore, this application case demonstrates the negative impact of uneven wall heat transfer on building energy consumption. For dry-jointed prefabricated walls, this uneven heat transfer can impact building thermal performance, necessitating the development of a suitable method for evaluating wall heat transfer uniformity.

Claims

1. A method for evaluating non-uniform heat transfer in dry-type joint assembly exterior walls, characterized in that: The following steps are included: S1: Focusing on the joints, the temperature distribution on the inner surface of the exterior wall is obtained by testing or simulating the heat transfer law of the dry-connected assembled exterior wall; S2: Determine the impact range of non-uniform heat transfer caused by dry-jointed wall panel joints based on the temperature distribution on the inner wall surface of the exterior wall; S3: Calculate the cumulative temperature difference ratio T' of the inner wall surface of the exterior wall; S4: Compare the cumulative temperature difference ratio T' between the exterior wall and the interior wall with 0.8 to evaluate the non-uniform heat transfer of the prefabricated building exterior wall; Regarding step S4, there is also a method for evaluating the significance of the non-uniform heat transfer effect of the wall. This evaluation method is derived from Fourier's law, taking into account the additional heat flow caused by non-uniform heat transfer, and is reflected by the indicator "non-uniform equivalent heat transfer coefficient KT"; When there is no internal heat source in the wall, the total heat passing through the wall is Q sum The calculation is as shown in formula (6), that is, the total heat passing through the wall is composed of the heat flow of the main body and the area affected by non-uniform heat transfer: Thus, the average heat transfer coefficient of the wall is Formula (7): Then, the non-uniform equivalent heat transfer coefficient K T It can be expressed as formula (8): In the above formula, is the average heat transfer coefficient of the wall, W / (㎡·K); K T is the non-uniform equivalent heat transfer coefficient, W / (㎡·K); Q sum is the total heat passing through the wall, W; K P is the main heat transfer coefficient, W / (㎡·K); F P is the area of the main part of the wall, m2; F T is the area of each non-uniform heat transfer part of the wall, m2; ΔT is the temperature difference between the inner and outer surfaces of the wall, °C; A is the sum of the areas of the non-uniform heat transfer part and the main part of the wall, m2; From the above formula, we can simplify and derive formula (9): Where l0 is the width of the area affected by non-uniform heat transfer, m; q (x) is a function of heat flux density, which can be obtained through Fluent simulation; F T0 is the area affected by non-uniform heat transfer, m2; h is the wall height, m; x0 and x1 are the starting and ending coordinates of the thermal bridge influence distance.

2. A method for evaluating non-uniform heat transfer for dry-type joint assembly exterior walls according to claim 1, characterized in that: In step S1, the temperature distribution curves at different distances from the inner surface of the wall are derived and recorded as t (x) .

3. The method for evaluating non-uniform heat transfer for dry-type joint assembly exterior walls according to claim 1, characterized in that: In step S2, the range of influence of the non-uniform heat transfer caused by the joint is calculated as follows: Under steady-state conditions, the temperature difference ratio ξ at any point of the enclosure structure satisfies the following formula: For the inner surface of the enclosure structure, the temperature difference ratios ξ1 and ξ1' at the normal location and the non-uniform heat transfer location satisfy the following formula: The location of the area affected by non-uniform heat transfer must satisfy the following formula: Where, t f1 is the indoor ambient temperature, °C; t f2 is the outdoor ambient temperature, °C; t P is the temperature of any point P on the inner surface, °C; t1 is the inner surface temperature of the normal part, °C; t′1 is the critical surface temperature in the area affected by non-uniform heat transfer, °C; The critical surface temperature t′1 in the area affected by non-uniform heat transfer can be obtained from equations (1) to (4), thereby determining the range of non-uniform heat transfer influence.

4. The method for evaluating non-uniform heat transfer for dry-type joint assembly exterior walls according to claim 1, characterized in that: In step S3, since the uneven heat transfer of the wall is manifested in two aspects: the distance of the thermal bridge and the temperature difference between the joint and the main body of the exterior wall, the cumulative temperature difference ratio T' is calculated by combining the influence of the two. The calculation method is shown in formula (5): Where, t (x) is the wall temperature distribution function, ℃; t0 is the temperature value of the main part, ℃; l is the coordinate of the area affected by non-uniform heat transfer, m; L is the coordinate of the main part, m.

5. The method for evaluating non-uniform heat transfer for dry-type joint assembly exterior walls according to claim 4, characterized in that: The T' is the ratio of the cumulative temperature difference T in the area affected by the non-uniform heat transfer to the cumulative temperature difference T0 of the entire wall. It reflects the severity of the temperature change on both sides of the wall caused by the joint and is used to reflect the non-uniform heat transfer of the wall caused by the joint. The larger the temperature change on both sides caused by the joint, the larger T, which makes T' larger and the more non-uniform the heat transfer of the wall.

6. The method for evaluating non-uniform heat transfer for dry-type joint assembly exterior walls according to claim 4, characterized in that: In step S4, when T'>0.8, the wall heat transfer is uneven.

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