CN103452206A - Civil building self-heat-insulation wall and heat transfer process computing method of same - Google Patents

Abstract

The invention discloses a civil building self-heat-insulation wall and a heat transfer process computing method of the same. The heat-insulation wall comprises an interior brick wall layer close to the indoor side, an exterior brick wall layer close to the outdoor layer and an overlap brick layer, and the interior brick wall layer, the exterior brick wall layer and the overlap brick layer consist of a plurality of interior wall bricks, exterior wall bricks and overlap bricks respectively. The interior wall bricks are parallel to the corresponding exterior wall bricks, the overlap bricks perpendicular to each of the interior wall bricks and the exterior wall bricks are arranged at two ends thereof, and the interior brick wall layer, the exterior brick wall layer and the overlap brick layer surround to form an air layer. By optimized design of a wall enclosure structure, heat insulation properties of an exterior wall are improved without changing a traditional brick and building block production mode, the requirements on heat transfer coefficients of the exterior wall in the southern China are met, and cost for engineering construction can be saved; meanwhile, an excellent heat insulation effect can be achieved, and building energy consumption can be lowered.

Description

The diabatic process computational methods of a kind of civilian construction self heat insulation wall and this body of wall

Technical field

The present invention relates to construction engineering technical field, particularly the diabatic process computational methods of a kind of civilian construction self heat insulation wall and this body of wall.

Background technology

Due to building always conduct heat energy input 80% by heat transfer across wall loss, therefore, the improvement of thermal performance of building envelope has very important significance for building energy conservation.Adopt appropriate space enclosing structure parts and rational construction measure can meet the various requirements such as insulation, heat insulation, daylighting, ventilation, both guaranteed indoor good physical environment, reduced again energy consumption, this is the primary condition that realizes building energy conservation.

The factor that the energy-saving design of space enclosing structure relates generally to has exterior wall, roof, door and window, curtain wall etc.Exterior wall is the main body of architectural exterior-protecting construction, and its heat-insulating property directly affects the heat consumption of building, and external wall energy-saving occupies very important position in building energy conservation, and the heat transfer heat consumption of exterior wall accounts for the 23%-34% of building total heat consumption according to statistics.Southern area (Xia Redong cryogenic region, hot summer and warm winter region) residential building, public building have carried out strict restriction to the thermal transmittance limit value of external wall respectively for this reason.Visible enhancing exterior wall thermal property has important function for building energy conservation.

The method that urban architecture is mainly laid heat insulating material by exterior wall improves the exterior wall thermal property, but can cause construction cost to increase owing to laying heat insulating material, and this has seriously restricted the popularization of the civilian space enclosing structure power-saving technology of some rural areas tradition.

Summary of the invention

The object of the invention is to: for the problem of above-mentioned existence, provide under a kind of condition not changing traditional brick block production model, can play good heat insulating effect and reduce the civilian construction self heat insulation wall of building energy consumption and the diabatic process computational methods of this body of wall.

The technical scheme of the technology of the present invention is achieved in that a kind of civilian construction self heat insulation wall, it is characterized in that: the outer brick wall layer and the overlap joint brick layer that comprise the interior brick wall layer near an indoor side, a close outdoor side, described interior brick wall layer, outer brick wall layer and overlap joint brick layer are comprised of some internal wall bricks, exterior wall tile and overlap joint brick respectively, described internal wall brick is arranged in parallel with corresponding exterior wall tile and is provided with it overlap joint brick at its two ends with being arranged vertically, and described interior brick wall layer, outer brick wall layer and overlap joint brick layer surround into air layer.

Civilian construction self heat insulation wall of the present invention, scribble respectively dope layer on its side corresponding with outer brick wall layer at described interior brick wall layer, the inside wall that contacts with air layer, and the emissivity of coatings of described dope layer is less than or equal to 0.4.

Civilian construction self heat insulation wall of the present invention, its described internal wall brick, exterior wall tile and overlap joint brick are all standing and are putting, and are staggered.

Civilian construction self heat insulation wall of the present invention, overlap joint brick two of its described overlap joint brick layer is respectively near indoor and outdoor.

A kind of diabatic process computational methods of civilian construction self heat insulation wall as described above, it is characterized in that: comprise the heat transfer of air layer body of wall and the heat transfer of overlap joint brick wall body, the heat transfer of described air layer body of wall comprises double teacher: 1. heat passes to the exterior wall outside in the mode of composite heat-exchange, 2. heat passes through exterior wall with heat-conducting mode, 3. inner side of outer wall passes to the interior wall outside in the mode of composite heat-exchange, 4. in the mode of heat conduction, by interior wall, 5. heat passes to indoor environment in the mode of composite heat-exchange to heat; The heat transfer of described overlap joint brick wall body comprises three phases: 1. heat passes to overlap joint brick wall outer side in the mode of composite heat-exchange, and 2. in the mode of heat conduction, by overlap joint brick brick body wall, 3. heat passes to indoor environment in the mode of composite heat-exchange to heat.

Diabatic process computational methods of the present invention is characterized in that:

The heat transfer of a, air layer body of wall:

1. outside wall surface heat convection, exterior surface of wall and air heat are with the complex form heat exchange, and the heat flow density of this process can be calculated with formula (one):

Q=h ₀(t _f0-t _w0) ... (1)

2. exterior wall heat conduction, heat passes through (interior wall is identical with the exterior wall computational methods) from the exterior wall outer surface in the mode of heat conduction, and the heat flow density of this process can be calculated with formula (two):

$q=\frac{t_{w0}-t_{w1}}{{\mathrm{\δ}}_0/{\mathrm{\λ}}_z}$ (2)

3. air space heat exchange, heat passes through air layer in the mode of composite heat-exchange, this process can be regarded the heat transfer free convection in the confined space as, and the air layer in body of wall is vertical wall interlayer, and heat transfer free convection Correlation equations and correlometer formula (three) are as follows:

(3)

Grashof:

$\mathrm{Gr}=\frac{\mathrm{g\α}(t_{w1}-t_{w2}){\mathrm{\δ}}_a^3}{v^2}$ (4)

Can draw the equivalent surface coefficient of heat transfer thus:

$h_e=\frac{{\mathrm{\λ}}_a}{{\mathrm{\δ}}_a}\mathrm{Nu}$ (5)

Body of wall radiating surface thermal transmittance:

$h_r=\mathrm{\ϵ}{C}_b\frac{T_{w1}^4-T_{w2}^4}{T_{w1}-T_{w2}}\×{10}^{-8}$ (6)

So air layer composite heat-exchange surface coefficient of heat transfer:

H ₁=h _e+ h _r(7)

Q=h ₁(t _w1-t _w2) ... (8)

4. interior wall heat conduction, heat passes through (interior wall is identical with the exterior wall computational methods) from the inner wall outer surface in the mode of heat conduction, and the heat flow density of this process can be calculated with formula (two):

$q=\frac{t_{w2}-{\mathrm{<figure-callout\; id="3"\; label="t\; w"\; filenames="130923095429.png"\; state="\{\{state\}\}">t</figure-callout>}}_w}{{\mathrm{\&delta;}}_0/{\mathrm{\&lambda;}}_z+{\mathrm{\&delta;}}_c/{\mathrm{\&lambda;}}_c}$ (9)

5. interior wall is in the face of the stream heat exchange, and body of wall inner surface and air heat are with the complex form heat exchange, and the heat flow density of this process can be calculated with formula (ten):

Q=h ₂(t _w3-t _f1) ... (10)

The heat transfer of b, overlap joint brick wall body:

Overlap joint brick wall inside and outside wall heat exchange design formulas, with the diabatic process of air layer body of wall, is calculated with (ten) according to formula (), and overlap joint brick wall body heat transferring is pressed formula (11) and calculated:

$q^{\&prime;}=\frac{t_{w0}-t_{w3}}{{\mathrm{\&delta;}}_1/{\mathrm{\&lambda;}}_z}$ (11)

C, body of wall average heat transfer:

Can draw the overall coefficient of heat transfer of this body of wall thus:

K=K _ka+K _sb ... (12)

$K_k=\frac{q}{t_{f0}-t_{f1}}$ (13)

$K_s=\frac{q^{\&prime;}}{t_{f0}-t_{f1}}$ (14)

A is the ratio that the hollow wall area accounts for whole wall area, m ²/ m ²;

B is the ratio that the solid wall area accounts for whole wall area, m ²/ m ²;

Heat exchange is calculated and is adopted trial and error procedure, and tentative calculation is crossed each section heat flow density error of range request and is controlled in 5%;

In above-mentioned design formulas, relevant parameter is as follows:

Q is for passing through air layer body of wall heat flow density, W/m ²

H ₀for exterior wall external surface composite heat-exchange coefficient, W/(m ²k)

T _f0for outside air temperature, ℃;

T _w0for exterior wall outer surface temperature, ℃

T _w1for the inner side of outer wall surface temperature, ℃

δ ₀for the thickness of brick, mm

λ _zfor the coefficient of thermal conductivity of brick, W/(m ²k)

H _efor equivalent surface coefficient of heat transfer, W/(m ²k)

λ _afor the coefficient of thermal conductivity of air, W/(m ²k)

The slin emissivity that ε is brick

H ₁for air layer composite surface thermal transmittance, W/(m ²k)

T _w3for interior wall inner surface temperature, ℃

H ₂for body of wall mean thermal transmittance W/(m ²k)

K is body of wall mean thermal transmittance W/(m ²k)

λ _cfor the coefficient of thermal conductivity of cement mortar, W/(m ²k)

Nu is nusselt number

H is the air layer height, m

Gr is grashof number

G is local acceleration of gravity, m ²/ s

α is the coefficient of cubical expansion, 1/K

T _w2for interior wall outer surface temperature, ℃

δ _afor air layer thickness, mm

ν is the dynamic viscosity of air under qualitative temperature, m ²/ s

H _rfor radiating surface thermal transmittance, W/(m ²k)

C _bblackbody coefficient, W/(m ²k ⁴)

T _f1for indoor air temperature, ℃;

Q ' is for passing through overlap joint brick wall body heat current density, W/m ²

δ ₁for the length of brick, mm

δ _cfor the thickness of cement mortar, mm.

The present invention is by the optimal design to masonry wall structure, realized under the condition that does not change traditional brick block production model, the heat-insulating property of exterior wall is improved, in the situation that do not adopt heat insulating material, also can meet the requirement of southern area heat transfer coefficient of outer wall, can save the engineering construction cost on the one hand, the effect that can also play good heat insulating effect simultaneously and reduce building energy consumption.

The accompanying drawing explanation

Fig. 1 is structural representation of the present invention.

Fig. 2 is Calculation of Heat Transfer process flow schematic diagram of the present invention.

Fig. 3 is civilian wall heat transfer coefficient (summer) schematic diagram under different emissivity.

Fig. 4 is civilian wall heat transfer coefficient (winter) schematic diagram under different emissivity.

Fig. 5 is civilian wall heat transfer coefficient under different emissivity (excessively season) schematic diagram.

Mark in figure: 1 is internal wall brick, and 2 is exterior wall tile, and 3 is the overlap joint brick, and 4 is air layer, and 5 is dope layer.

The specific embodiment

Below in conjunction with accompanying drawing, the present invention is described in detail.

In order to make purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the technology of the present invention is further elaborated.Should be appreciated that specific embodiment described herein is only in order to explain the present invention, and be not used in the restriction invention.

As shown in Figure 1, a kind of civilian construction self heat insulation wall, comprise the interior brick wall layer near an indoor side, outer brick wall layer and overlap joint brick layer near an outdoor side, described interior brick wall layer, outer brick wall layer and overlap joint brick layer are respectively by some internal wall bricks 1, exterior wall tile 2 and overlap joint brick 3 form, described internal wall brick 1 is arranged in parallel with corresponding exterior wall tile 2 and is provided with it overlap joint brick 3 at its two ends with being arranged vertically, overlap joint brick 3 two of described overlap joint brick layer are respectively near indoor and outdoor, described interior brick wall layer, outer brick wall layer and overlap joint brick layer surround into air layer 4, described internal wall brick 1, exterior wall tile 2 and overlap joint brick 3 are all standing and are putting, and be staggered.

Wherein, at described interior brick wall layer, on a side corresponding with outer brick wall layer, the inside wall that contacts with air layer 4, scribble respectively dope layer 5, the emissivity of coatings of described dope layer 5 is less than or equal to 0.4.

Specific embodiment:

Embodiment builds overview: the high 3.3m of this external wall body of wall, and wide 10.3m, the brickwork that uses is of a size of 240 * 115 * 53mm.The calculating parameter input parameter is as following table:

The calculating parameter input table

Wherein, the computational methods flow process as shown in Figure 2.

Through above hypothesis, the diabatic process computational methods of civilian construction self heat insulation wall described above, comprise the heat transfer of air layer body of wall and the heat transfer of overlap joint brick wall body, the heat transfer of described air layer body of wall comprises double teacher: 1. heat passes to the exterior wall outside in the mode of composite heat-exchange, 2. heat passes through exterior wall with heat-conducting mode, 3. inner side of outer wall passes to the interior wall outside in the mode of composite heat-exchange, 4. in the mode of heat conduction, by interior wall, 5. heat passes to indoor environment in the mode of composite heat-exchange to heat; The heat transfer of described overlap joint brick wall body comprises three phases: 1. heat passes to overlap joint brick wall outer side in the mode of composite heat-exchange, and 2. in the mode of heat conduction, by overlap joint brick brick body wall, 3. heat passes to indoor environment in the mode of composite heat-exchange to heat.

Wherein, the heat transfer of a, air layer body of wall:

1. outside wall surface heat convection, exterior surface of wall and air heat are with the complex form heat exchange, and the heat flow density of this process can be calculated with formula (one):

Q=h ₀(t _f0-t _w0) ... (1)

2. exterior wall heat conduction, heat passes through (interior wall is identical with the exterior wall computational methods) from the exterior wall outer surface in the mode of heat conduction, and the heat flow density of this process can be calculated with formula (two):

$q=\frac{t_{w0}-t_{w1}}{{\mathrm{\&delta;}}_0/{\mathrm{\&lambda;}}_z}$ (2)

3. air space heat exchange, heat passes through air layer in the mode of composite heat-exchange, this process can be regarded the heat transfer free convection in the confined space as, and the air layer in body of wall is vertical wall interlayer, and heat transfer free convection Correlation equations and correlometer formula (three) are as follows:

(3)

Grashof:

$\mathrm{Gr}=\frac{\mathrm{g\&alpha;}(t_{w1}-t_{w2}){\mathrm{\&delta;}}_a^3}{v^2}$ (4)

Can draw the equivalent surface coefficient of heat transfer thus:

$h_e=\frac{{\mathrm{\&lambda;}}_a}{{\mathrm{\&delta;}}_a}\mathrm{Nu}$ (5)

Body of wall radiating surface thermal transmittance:

$h_r=\mathrm{\&epsiv;}{C}_b\frac{T_{w1}^4-T_{w2}^4}{T_{w1}-T_{w2}}\&times;{10}^{-8}$ (6)

So air layer composite heat-exchange surface coefficient of heat transfer:

H ₁=h _e+ h _r(7)

Q=h ₁(t _w1-t _w2) ... (8)

4. interior wall heat conduction, heat passes through (interior wall is identical with the exterior wall computational methods) from the inner wall outer surface in the mode of heat conduction, and the heat flow density of this process can be calculated with formula (two):

$q=\frac{t_{w2}-{\mathrm{<figure-callout\; id="3"\; label="t\; w"\; filenames="130923095429.png"\; state="\{\{state\}\}">t</figure-callout>}}_w}{{\mathrm{\&delta;}}_0/{\mathrm{\&lambda;}}_z+{\mathrm{\&delta;}}_c/{\mathrm{\&lambda;}}_c}$ (9)

5. interior wall is in the face of the stream heat exchange, and body of wall inner surface and air heat are with the complex form heat exchange, and the heat flow density of this process can be calculated with formula (ten):

Q=h ₂(t _w3-t _f1) ... (10)

The heat transfer of b, overlap joint brick wall body:

Overlap joint brick wall inside and outside wall heat exchange design formulas, with the diabatic process of air layer body of wall, is calculated with (ten) according to formula (), and overlap joint brick wall body heat transferring is pressed formula (11) and calculated:

$q^{\&prime;}=\frac{t_{w0}-{\mathrm{<figure-callout\; id="3"\; label="t\; w"\; filenames="130923095429.png"\; state="\{\{state\}\}">t</figure-callout>}}_w}{{\mathrm{\&delta;}}_1/{\mathrm{\&lambda;}}_z}$ (11)

C, body of wall average heat transfer:

Can draw the overall coefficient of heat transfer of this body of wall thus:

K=K _ka+K _sb ... (12)

$K_k=\frac{q}{t_{f0}-t_{f1}}$ (13)

$K_s=\frac{q^{\&prime;}}{t_{f0}-t_{f1}}$ (14)

A is the ratio that the hollow wall area accounts for whole wall area, m ²/ m ²;

B is the ratio that the solid wall area accounts for whole wall area, m ²/ m ²;

Heat exchange is calculated and is adopted trial and error procedure, and tentative calculation is crossed each section heat flow density error of range request and is controlled in 5%;

In above-mentioned design formulas, relevant parameter is as follows:

Q is for passing through air layer body of wall heat flow density, W/m ²

H ₀for exterior wall external surface composite heat-exchange coefficient, W/(m ²k)

T _f0for outside air temperature, ℃;

T _w0for exterior wall outer surface temperature, ℃

T _w1for the inner side of outer wall surface temperature, ℃

δ ₀for the thickness of brick, mm

λ _zfor the coefficient of thermal conductivity of brick, W/(m ²k)

H _efor equivalent surface coefficient of heat transfer, W/(m ²k)

λ _afor the coefficient of thermal conductivity of air, W/(m ²k)

The slin emissivity that ε is brick

H ₁for air layer composite surface thermal transmittance, W/(m ²k)

T _w3for interior wall inner surface temperature, ℃

H ₂for body of wall mean thermal transmittance W/(m ²k)

K is body of wall mean thermal transmittance W/(m ²k)

λ _cfor the coefficient of thermal conductivity of cement mortar, W/(m ²k)

Nu is nusselt number

H is the air layer height, m

Gr is grashof number

G is local acceleration of gravity, m ²/ s

α is the coefficient of cubical expansion, 1/K

T _w2for interior wall outer surface temperature, ℃

δ _afor air layer thickness, mm

ν is the dynamic viscosity of air under qualitative temperature, m ²/ s

H _rfor radiating surface thermal transmittance, W/(m ²k)

C _bblackbody coefficient, W/(m ²k ⁴)

T _f1for indoor air temperature, ℃;

Q ' is for passing through overlap joint brick wall body heat current density, W/m ²

δ ₁for the length of brick, mm

δ _cfor the thickness of cement mortar, mm.

Result of calculation: as shown in Fig. 3 to 5, as can be seen from the figure, no matter in which, thermal characteristic of wall is good, and (the body of wall mean thermal transmittance is about 0.7W/m in season ²k), substantially meet energy-conserving construction wall thermal technology requirement.As can be seen here, one aspect of the present invention can be saved the engineering construction cost, the effect that can also play good heat insulating effect simultaneously and reduce building energy consumption.

Claims (6)

1. a civilian construction self heat insulation wall, it is characterized in that: the outer brick wall layer and the overlap joint brick layer that comprise the interior brick wall layer near an indoor side, a close outdoor side, described interior brick wall layer, outer brick wall layer and overlap joint brick layer are comprised of some internal wall bricks (1), exterior wall tile (2) and overlap joint brick (3) respectively, described internal wall brick (1) is arranged in parallel with corresponding exterior wall tile (2) and is provided with it overlap joint brick (3) at its two ends with being arranged vertically, and described interior brick wall layer, outer brick wall layer and overlap joint brick layer surround into air layer (4).

2. civilian construction self heat insulation wall according to claim 1, it is characterized in that: scribble respectively dope layer (5) at described interior brick wall layer on a side corresponding with outer brick wall layer, the inside wall that contacts with air layer (4), the emissivity of coatings of described dope layer (5) is less than or equal to 0.4.

3. civilian construction self heat insulation wall according to claim 2 is characterized in that: described internal wall brick (1), exterior wall tile (2) and overlap joint brick (3) are all standing and are putting, and are staggered.

4. according to claim 1,2 or 3 described civilian construction self heat insulation walls, it is characterized in that: overlap joint brick (3) two of described overlap joint brick layer is respectively near indoor and outdoor.

5. the diabatic process computational methods of a civilian construction self heat insulation wall as described above, it is characterized in that: comprise the heat transfer of air layer body of wall and the heat transfer of overlap joint brick wall body, the heat transfer of described air layer body of wall comprises double teacher: 1. heat passes to the exterior wall outside in the mode of composite heat-exchange, 2. heat passes through exterior wall with heat-conducting mode, 3. inner side of outer wall passes to the interior wall outside in the mode of composite heat-exchange, 4. in the mode of heat conduction, by interior wall, 5. heat passes to indoor environment in the mode of composite heat-exchange to heat; The heat transfer of described overlap joint brick wall body comprises three phases: 1. heat passes to overlap joint brick wall outer side in the mode of composite heat-exchange, and 2. in the mode of heat conduction, by overlap joint brick brick body wall, 3. heat passes to indoor environment in the mode of composite heat-exchange to heat.

6. diabatic process computational methods according to claim 5 is characterized in that:

The heat transfer of a, air layer body of wall:

1. outside wall surface heat convection, exterior surface of wall and air heat are with the complex form heat exchange, and the heat flow density of this process can be calculated with formula (one):

Q=h ₀(t _f0-t _w0) ... (1)

2. exterior wall heat conduction, heat passes through (interior wall is identical with the exterior wall computational methods) from the exterior wall outer surface in the mode of heat conduction, and the heat flow density of this process can be calculated with formula (two):

$q=\frac{t_{w0}-t_{w1}}{{\mathrm{\&delta;}}_0/{\mathrm{\&lambda;}}_z}$ (2)

3. air space heat exchange, heat passes through air layer in the mode of composite heat-exchange, this process can be regarded the heat transfer free convection in the confined space as, and the air layer in body of wall is vertical wall interlayer, and heat transfer free convection Correlation equations and correlometer formula (three) are as follows:

(3)

Grashof:

$\mathrm{Gr}=\frac{\mathrm{g\&alpha;}(t_{w1}-t_{w2}){\mathrm{\&delta;}}_a^3}{v^2}$ (4)

Can draw the equivalent surface coefficient of heat transfer thus:

$h_e=\frac{{\mathrm{\&lambda;}}_a}{{\mathrm{\&delta;}}_a}\mathrm{Nu}$ (5)

Body of wall radiating surface thermal transmittance:

$h_r=\mathrm{\&epsiv;}{C}_b\frac{T_{w1}^4-T_{w2}^4}{T_{w1}-T_{w2}}\&times;{10}^{-8}$ (6)

So air layer composite heat-exchange surface coefficient of heat transfer:

H ₁=h _e+ h _r(7)

Q=h ₁(t _w1-t _w2) ... (8)

4. interior wall heat conduction, heat passes through (interior wall is identical with the exterior wall computational methods) from the inner wall outer surface in the mode of heat conduction, and the heat flow density of this process can be calculated with formula (two):

$q=\frac{t_{w2}-t_{w3}}{{\mathrm{\&delta;}}_0/{\mathrm{\&lambda;}}_z+{\mathrm{\&delta;}}_c/{\mathrm{\&lambda;}}_c}$ (9)

5. interior wall is in the face of the stream heat exchange, and body of wall inner surface and air heat are with the complex form heat exchange, and the heat flow density of this process can be calculated with formula (ten):

Q=h ₂(t _w3-t _f1) ... (10)

The heat transfer of b, overlap joint brick wall body:

Overlap joint brick wall inside and outside wall heat exchange design formulas, with the diabatic process of air layer body of wall, is calculated with (ten) according to formula (), and overlap joint brick wall body heat transferring is pressed formula (11) and calculated:

$q^{\&prime;}=\frac{t_{w0}-t_{w3}}{{\mathrm{\&delta;}}_1/{\mathrm{\&lambda;}}_z}$ (11)

C, body of wall average heat transfer:

Can draw the overall coefficient of heat transfer of this body of wall thus:

K=K _ka+K _sb ... (12)

$K_k=\frac{q}{t_{f0}-t_{f1}}$ (13)

$K_s=\frac{q^{\&prime;}}{t_{f0}-t_{f1}}$ (14)

A is the ratio that the hollow wall area accounts for whole wall area, m ²/ m ²;

B is the ratio that the solid wall area accounts for whole wall area, m ²/ m ²;

Heat exchange is calculated and is adopted trial and error procedure, and tentative calculation is crossed each section heat flow density error of range request and is controlled in 5%;

In above-mentioned design formulas, relevant parameter is as follows:

Q is for passing through air layer body of wall heat flow density, W/m ²

H ₀for exterior wall external surface composite heat-exchange coefficient, W/(m ²k)

T _f0for outside air temperature, ℃;

T _w0for exterior wall outer surface temperature, ℃

T _w1for the inner side of outer wall surface temperature, ℃

δ ₀for the thickness of brick, mm

λ _zfor the coefficient of thermal conductivity of brick, W/(m ²k)

H _efor equivalent surface coefficient of heat transfer, W/(m ²k)

λ _afor the coefficient of thermal conductivity of air, W/(m ²k)

The slin emissivity that ε is brick

H ₁for air layer composite surface thermal transmittance, W/(m ²k)

T _w3for interior wall inner surface temperature, ℃

H ₂for body of wall mean thermal transmittance W/(m ²k)

K is body of wall mean thermal transmittance W/(m ²k)

λ _cfor the coefficient of thermal conductivity of cement mortar, W/(m ²k)

Nu is nusselt number

H is the air layer height, m

Gr is grashof number

G is local acceleration of gravity, m ²/ s

α is the coefficient of cubical expansion, 1/K

T _w2for interior wall outer surface temperature, ℃

δ _afor air layer thickness, mm

ν is the dynamic viscosity of air under qualitative temperature, m ²/ s

H _rfor radiating surface thermal transmittance, W/(m ²k)

C _bblackbody coefficient, W/(m ²k ⁴)

T _f1for indoor air temperature, ℃;

Q ' is for passing through overlap joint brick wall body heat current density, W/m ²

δ ₁for the length of brick, mm

δ _cfor the thickness of cement mortar, mm.

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