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Annex A (Air Conditioning)

A.1 Calculation Method for Thermal Transmittance of Exterior Walls, etc.

The method for calculating the thermal transmittance of exterior walls, etc. (exterior walls, roofs, and floors in contact with outside air) is specified as follows.

Table 152. Input
Variable Name Description Unit Reference

\(MATERIAL_{k}\)

Building material type of the k-th constituent material

m

Form 2-2: (4) Building Material Number, (5) Building Material Name

\(l_{k}\)

Thickness of the k-th constituent material

m

Form 2-2: (6) Thickness
Table 153. Output
Variable Name Description Unit Reference

\(U_{wall}\)

Thermal transmittance of exterior walls, etc.

W/(m2・K)

2.4.2.2, 2.4.2.4, 2.4.2.6

First, the thermal conductivity \(λ_{k}\) W/(m2・K) of the building material type \(MATERIAL_{k}\) is retrieved from the building materials’ database.

The thermal transmittance of an exterior wall \(U_{wall}\) is obtained by the following formula.

\[ U_{wall} = \frac{ 1 }{ \frac{1}{\alpha_{i}} + \sum_{k} \frac{l_{k}}{\lambda_{k}} + \frac{1}{\alpha_{o}} } \]

For the thermal conductivity \(λ_{k}\) of each material, the specified value should be used. However, if the k-th constituent material is an "unsealed air layer", \(l_{k}/λ_{k}\) should be 0.09(m2・K)/W. The influence of thermal bridges in exterior walls, etc. is not considered.

A.2 Calculation Method for the Thermal Transmittance and Solar Heat Gain Coefficient of Windows

The method for calculating the thermal transmittance and solar heat gain coefficient of windows (glass + building fixture) is specified as follows.

Table 154. Input
Variable Name Description Unit References

\(U_{wind,j,input}\)

Thermal transmittance of window

W/m2K

Form 2-3: (2) Thermal Transmittance of Window

\(\eta_{wind,j,input}\)

Solar heat gain rate of window

-

Form 2-3: (3) Solar Heat Gain Coefficient of Window

Building Fixture Type

Form 2-3: (4) Type of Building Materials

Glass type (ex:3WgG06)

Form 2-3: (5) Type of Glass

\(U_{glass,j,input}\)

Thermal transmittance of glass

W/m2K

Form 2-3: (6) Thermal Transmittance of Glass

\(\eta_{glass,j,input}\)

Solar heat gain coefficient of glass

-

Form 2-3: (7) Solar Heat Gain Coefficient of Glass
Table 155. Output
Variable Name Description Unit Reference

\(U_{wind,j}\)

Thermal transmittance of window, etc. j (without blinds)

W/m2K

2.4.2.3, 2.4.2.5

\(U_{wind,j,bl}\)

Thermal transmittance of window, etc. j (with blinds)

W/m2K

2.4.2.3, 2.4.2.5

\(\eta_{wind,j}\)

Solar heat gain rate of window, etc. j (without blinds)

-

2.4.2.7

\(\eta_{wind,j,bl}\)

Solar heat gain rate of window, etc. j (with blinds)

-

2.4.2.7

There are the following three input methods for thermal transmittance and solar heat gain coefficient. If there are multiple entries on Form 2-3, Method 1 shall take precedence, followed by Method 2, and then Method 3.

  • Method 1: Directly input the thermal transmittance and the solar heat gain coefficient of windows, etc. (Form 2-3 (2), (3) ).
  • Method 2: Select the building fixture type and the glass type (Form 2-3 (4) , (5) ).
  • Method 3: Select the building fixture type and enter the thermal transmittance and solar heat gain coefficient of glass (Form 2-3 (4) , (6) , (7) ).

(Method 1) Directly input the thermal transmittance and the solar heat gain coefficient of windows, etc.

The thermal transmittance \(U_{wind,j}\) and the solar heat gain \(\eta_{wind,j}\) of the window without blinds are obtained by the following formula.

\[ U_{wind,j} = U_{wind,j,input} \]
\[ \eta_{wind,j} = \eta_{wind,j,input} \]

When blinds are present, the heat transfer coefficient and the solar heat gain coefficient are calculated individually based on the presence or absence of inputs of \(U_{glass,j,input}\) and \(\eta_{glass,j,input}\).

a) If there is no input for glass performance \(U_{glass,j,input}\), \(\eta_{glass,j,input}\),

\[ U_{wind,j,bl} = U_{wind,j,input} \]
\[ \eta_{wind,j,bl} = \eta_{wind,j,input} \]

b) If there are inputs for glass performance \(U_{glass,j,input}\), \(\eta_{glass,j,input}\),

\[ dR = \frac{0.021}{U_{glass,j}} + 0.022 \]
\[ U_{wind,j,bl} = \frac{1}{ \left( \frac{1}{U_{wind,j,input}} + dR \right) } \]
\[ \eta_{wind,j,bl} = \frac{\eta_{wind,j,input}}{\eta_{glass,j}} \times \left( -0.1331\,\eta_{glass,j}^{2} + 0.8258\,\eta_{glass,j} \right) \]

(Method 2) Select the building fixture type and the glass type.

From the "Window Performance List Database", retrieve the relevant values according to the entered building fixture type and glass type. The values listed in this database were calculated by WindEye, the program that evaluates the thermal performance of openings.

(Reference) Window Performance List Database ( WindowHeatTransferPerformance_H30.csv ):

Table 156. Example when building fixture type is "resin" and glass type is "3WgG06".

\(U_{wind,j}\)=1.95

\(U_{wind,j,bl}\)= 1.82

\(\eta_{wind,j}\)= 0.39

\(\eta_{wind,j,bl}\)= 0.30

(Method 3) Select the building fixture type and enter the thermal transmittance and solar heat gain coefficient of glass.

\[ U_{wind,j} = k_{u,a} \, U_{glass,j,input} + k_{u,b} \]
\[ \eta_{wind,j} = k_{\eta} \, \eta_{glass,j,input} \]
\[ dR = \frac{0.021}{U_{glass,j,input}} + 0.022 \]
\[ U_{wind,j,bl} = \frac{ 1 }{ \left( \frac{1}{U_{wind,j}} + dR \right) } \]
\[ \eta_{wind,j,bl} = k_{\eta} \left( -0.1331\,\eta_{glass,j,input}^{2} + 0.8258\,\eta_{glass,j,input} \right) \]

The coefficients \(k_{u,a}\), \(k_{u,b}\), and \(k_{\eta}\) are determined by the building fixture type as follows.

Table 157. Conversion coefficient to thermal transmittance of windows (for each building fixture type).
Building Fixture Type \(k_{u,a}\) \(k_{u,b}\) \(k_{\eta}\)

Resin(triple glazing)

0.659

0.91

0.72

Resin(double glazing)

0.659

1.04

0.72

Resin(single glazing)

0.659

0.82

0.72

Wood(triple glazing)

0.659

0.91

0.72

Wood(double glazing)

0.659

1.04

0.72

Wood(single glazing)

0.659

0.82

0.72

Metal-Plastic composite(triple glazing)

0.800

0.95

0.8

Metal-Plastic composite(double glazing)

0.800

1.15

0.8

Metal-Plastic composite(single glazing)

0.800

0.88

0.8

金属木複合製(triple glazing)

0.800

0.95

0.8

金属木複合製(double glazing)

0.800

1.15

0.8

Metal-Wood composite(single glazing)

0.800

0.88

0.8

Metal(double glazing)

0.812

1.51

0.8

Metal(single glazing)

0.812

1.39

0.8

A.3 Coefficient for Room Load Calculation

Table 158. Input
Variable Name Description Unit Reference

\(ClimateZone\)

Climate zone of the location of the building subject to evaluation

-

Form 0: (5) Regional Categories in Buildling Energy Codes

\(RoomType_{i}\)

Room use of room

－

Form 2-1: (1) Building Use and Room Use

\(Season_{d}\)

Cooling/heating season (cooling, intermediate, or heating seasons) on date \(d\)

\(m^2\)

2.2.2

\(O_{AC,room,i,d}\)

Operating status of the air conditioner in room i on date \(d\)

Boolean value

2.3.3
Table 159. Output
Variable Name Description Unit Reference

\(a_{tc1,d}, a_{tc2,d}\)

Coefficient for converting steady-state heat gain caused by temperature difference on date \(d\) to room load (cooling)

-

2.4.4

\(a_{th1,d}, a_{th2,d}\)

Coefficient for converting steady-state heat gain caused by temperature difference on date \(d\) to room load (heating)

-

2.4.4

\(a_{sc1,d}, a_{sc2,d}\)

Coefficient for converting steady-state heat gain due to solar radiation on date \(d\) to room load (cooling)

-

2.4.4

The coefficient for load calculation is specified in the following files for each region, room use, and air conditioner operation mode. Note that the coefficient differs depending on whether the previous day was an air-conditioned or non-air-conditioned day.

A.4 Heat Source Characteristics

Table 160. Input
Variable Name Description Unit Reference

\(RefType_{i,j}\)

Heat source device model of the heat source device j belonging to the heat source group

-

Form 2-5: (6) Heat Source Device Model

\(CtrlMode_{AC,ref,i}\)

Operation mode of the heat source group

Cooling/Heating heat source

2.7
Table 161. Output
Variable Name Description Unit Reference

\(a_{ref,q,i,j},b_{ref,q,i,j},c_{ref,q,i,j},d_{ref,q,i,j},e_{ref,q,i,j}\)

Coefficient of maximum capacity characteristic of the heat source device j belonging to the heat source group

-

2.7.8

\(\theta_{ref,q,i,j,min},\theta_{ref,q,i,j,max}\)

Minimum and maximum temperatures of maximum capacity characteristic of the heat source device j belonging to the heat source group

℃

2.7.8

\(a_{ref,p,i,j},b_{ref,p,i,j},c_{ref,p,i,j},d_{ref,p,i,j},e_{ref,p,i,j}\)

Coefficient of maximum input characteristic of the heat source device j belonging to the heat source group

-

2.7.11

\(\theta_{ref,p,i,j,min},\theta_{ref,p,i,j,max}\)

Minimum and maximum temperatures of the maximum input characteristic of the heat source device j belonging to the heat source group

℃

2.7.11

\(a_{ref,x,i,j},b_{ref,x,i,j},c_{ref,x,i,j},d_{ref,x,i,j},e_{ref,x,i,j}\)

Coefficient of partial load characteristic of the heat source device j belonging to the heat source group

-

2.7.13

\(L_{ref,x,i,j,min},L_{ref,x,i,j,max}\)

Minimum and maximum load factor of partial load characteristic of the heat source device j belonging to the heat source group

-

2.7.13

\(a_{ref,t,i,j},b_{ref,t,i,j},c_{ref,t,i,j},d_{ref,t,i,j},e_{ref,t,i,j}\)

Coefficient of water supply temperature characteristic of the heat source device j belonging to the heat source group

-

2.7.14

\(\theta_{ref,t,i,j,min},\theta_{ref,t,i,j,max}\)

Minimum and maximum load factors of water supply temperature characteristic of the heat source device j belonging to the heat source group

-

2.7.14

The coefficients relating to the energy consumption characteristics of a heat source device are specified in "REFCURVE_H28.csv".
The ID that identifies the coefficient is specified in "REFLIST_H28.csv" for each heat source device model.

  • Obtain a specific ID.

Obtain a specific ID from REFLIST_H28.csv using the heat source device model \(RefType_{i,j}\), the operation mode of the heat source group i \(CtrlMode_{AC,ref,i}\), and the type of characteristic (maximum capacity, maximum input, partial load, water temperature).

Example: If the heat source device model is "Water chilling unit (air-cooled)", the operation mode is "cooling source" and the characteristic type is "Maximum capacity", obtain the value (Cq_AS_A) in the "Specific ID" column of the row whose "Device Model" column is "Water chilling unit (air-cooled)", whose "Cooling/Heating" column is "Cooling" and whose "Characteristic type" column is "Capacity ratio".

The correspondence between "Characteristic type" and "Characteristic type value" is as follows.
Maximum capacity →Capacity ratio
Maximum input →Input ratio
Partial load →Partial load characteristics
Water supply temperature →Water supply temperature characteristic

  • Obtain the minimum and maximum values.

Obtain minimum and maximum values from REFLIST_H28.csv using the heat source device model \(RefType_{i,j}\), the operation mode of heat source group i \(CtrlMode_{AC,ref,i}\) , and the type of characteristic (maximum capacity, maximum input, partial load, water temperature).

Example: If the heat source device model is "Water chilling unit (air-cooled)" and the Characteristic type is "Maximum capacity", find the row whose "Device model" is "Water chilling unit (air-cooled)", whose "Cooling/Heating" column is "Cooling", and whose "Characteristic type" column is "Capacity ratio", and obtain the value in the "Lower limit" column (25) as the minimum value, and the value in the "Upper limit" column (40) as the maximum value.
  • Obtain the characteristic coefficients (a, b, c, d, e).

Obtain the characteristic coefficients from REFCURVE_H28.csv using the characteristic ID.

Example: If the Specific ID is "Cq_AS_A", find the row whose "Name" column is "Cq_AS_A", and obtain the value in the column "x4" (0) for a, the value in the column "x3" (0) for b, the value in the column "x2" (0) for c, the value in the column "x1" (-0.0091) for d, the value in the column "a" (1.3185) for e.

If a specific ID is duplicated (e.g. capacity ratio of water chilling unit (air-cooled) during heating), this is a case where the characteristic coefficient varies depending on the input value range. Adopt a coefficient with a minimum and a maximum value that accommodates the input value. If the input value is less than the minimum value of all cases, adopt the coefficient with the smallest "minimum value"; if the input value is greater than the maximum value, adopt the coefficient with the largest "maximum value".