National Institute for Land and Infrastructure Management (NILIM), Ministry of Land, Infrastructure and Building Research Institute (BRI), Transport and Tourism, National Research and Development Agency

10. Method for Calculating Primary Energy Consumptions under the Building Energy Code

This chapter shows the logic for calculating primary energy consumptions under the Building Energy Code.
A primary energy consumption under the Building Energy Code, \(E_\{T}\) [GJ/year], should be calculated from the following formula and be a value rounded up to the second decimal place.

\[E_\{ST} = (E_\{SAC} + E_\{SV} + E_\{SL} + E_\{SHW} + E_\{SEV} + E_\{M} ) \times 10^{-3}\]

\(E_\{SAC}\) is a primary energy consumption under the Building Energy Code of air conditioning equipment. The method for calculating the consumption is shown in 10.1. \(E_\{SV}\) is a primary energy consumption under the Building Energy Code of mechanical ventilation equipment. The method for calculating the consumption is shown in 10.2. \(E_\{SL}\) is a primary energy consumption under the Building Energy Code of a lighting installation. The method for calculating the consumption is shown in 10.3. \(E_\{SHW}\) is a primary energy consumption under the Building Energy Code of a hot-waste supply system. The method for calculating the consumption is shown in 10.4. \(E_\{SEV}\) is a primary energy consumption under the Building Energy Code of an elevator. The method for calculating the consumption is shown in 10.5. \(E_\{M}\) is other primary energy consumption. The method for calculating the consumption is shown in Chapter 9

For the coefficient in Appended Table 2 of MLIT’s 2016 Notification No. 265, and the basis for determining the relevant coefficient, refer to the following information.

Technical information on energy consumption performance evaluation that conforms to the 2016 Building Energy Code (non-residential buildings), Building Research Institute (BRI)
*4. Information on Standard Value, 4.1 Information on the standard value of primary energy consumption *Obtain a search key for the database. *https://www.kenken.go.jp/becc/documents/building/Definitions/kaisetsusyo_DefaultSpec_20140602.pdf[https://www.kenken.go.jp/becc/documents/building/Definitions/kaisetsusyo_DefaultSpec_20140602.pdf]

10.1 Primary Energy Consumption under the Building Energy Code of Air Conditioning Equipment

Table 1. Input
Variable name Description Unit Reference

\(CLIMATEZONE\)

Climate zone of the location of the building subject to evaluation

-

Form 0: ⑤ Climate zone under the Building Energy Code

\(ROOMTYPE_{AC,r}\)

Building and room uses of room r to be calculated for air conditioning

-

Form 2-1: ① Building and room uses

\(A_{AC,r}\)

Floor area of room r to be calculated for air conditioning

m2

Form 2-1: ① Room Area

\(n_\{AC}\)

Number of rooms to be calculated for air conditioning

-

Form 2-1: ① Number of total rows for inputting room names

Table 2. Output
Variable Name Description Unit References

\(E_\{SAC}\)

Primary energy consumption under the Building Energy Code of air conditioning equipment

MJ/year

Calculate a primary energy consumption of air conditioning equipment, \(E_\{SAC}\) [MJ/year], from the following formula.

\[E_\{SAC} = \sum_{r=1}^{n_\{AC}} (a_{SAC,r} \times A_\{r} )\]

A coefficient \(a_{SAC,r}\) [MJ/ (m2・year)] is a value that is specified in Appended Table 2 of MLIT’s 2016 Notification No. 265, and a primary energy consumption under the Building Energy Code per floor area. This coefficient is specified for each room use and each climate zone of a room to be calculated for air conditioning. Based on Form 0: Climate zone under the Building Energy Code (\(CLIMATEZONE\) ) and Form 2-1 of room r to be calculated for air conditioning: 2-1: ① Building and room uses (tem:[ROOMTYPE_{AC,r}]), an applicable coefficient \(a_{SAC,r}\) is extracted from Appended Table 2 of MLIT’s 2016 Notification No. 265.

Σ in the formula means the accumulation of primary energy consumptions of all rooms to be calculated for air conditioning in the input sheet. Specifically, primary energy consumptions of all rooms inputted into “Form 2-1 Air conditioning zone input sheet” are accumulated. For a floor area \(A_{AC,r}\) , a value inputted into Form 2-1: ① Floor area is used.

10.2 Primary Energy Consumption under the Building Energy Code of Mechanical Ventilation Equipment

Table 3. Input
Variable Name Description Unit Reference

\(ROOMTYPE_{V,r}\)

Building and room uses of room r to be calculated for ventilation

-

Form 3-1: ① Building and room uses

\(A_{V,r}\)

Floor area of room r to be calculated for ventilation

m2

Form 3-1: ① Room Area

\(n_\{V}\)

Number of rooms to be calculated for ventilation

-

Form 3-1: ① Number of total rows for inputting room names

Table 4. Output
Variable Name Description Unit References

\(E_\{SV}\)

Primary energy consumption under the Building Energy Code of mechanical ventilation equipment

MJ/year

Calculate a primary energy consumption of mechanical ventilation equipment, \(E_\{SV}\) [MJ/year], from the following formula.

\[E_\{SV} = \sum_{r=1}^{n_\{V}} (a_{SV,r} \times A_{V,r} )\]

A coefficient \(a_{SV,r}\) [MJ/(m2・year)] is a value that is specified in Appended Table 2 of MLIT’s 2016 Notification No. 265, and a primary energy consumption under the Building Energy Code per floor area. This coefficient is specified for each room use and each climate zone of a room to be calculated for ventilation. Based on Form 3-1 of room r to be calculated for ventilation: ① Building and room uses \(ROOMTYPE_{V,r}\) ), an applicable coefficient \(a_{SV,r}\) is extracted from Appended Table 2 of MLIT’s 2016 Notification No. 265.

Σ in the formula means the accumulation of primary energy consumptions of all rooms to be calculated for ventilation in the input sheet. Specifically, primary energy consumptions of all rooms inputted into “Form 3-1 Ventilation room input sheet” are accumulated. For a floor area \(A_{V,r}\) , a value inputted into Form 3-1: ① Room area is used.

10.3 Primary Energy Consumption under the Building Energy Code of Lighting Installation

Table 5. Input
Variable Name Description Unit Reference

\(ROOMTYPE_{L,r}\)

Building and room uses of room r to be calculated for lighting

-

Form 4: ① Building and room uses

\(A_{L,r}\)

Floor area of room r to be calculated for lighting

m2

Form 4: ① Room area

\(n_\{L}\)

Number of rooms to be calculated for lighting

-

Form 4: ① Number of total rows for inputting room names

Table 6. Output
Variable Name Description Unit References

\(E_\{SL}\)

Primary energy consumption under the Building Energy Code of lighting installation

MJ/year

Calculate a primary energy consumption of a lighting installation, \(E_\{SL}\) [MJ/year], from the following formula.

\[E_\{SL} = \sum_{r=1}^{n_\{L}} (a_{SL,r} \times A_{L,r} )\]

A coefficient \(a_{SL,r}\) [MJ/(m2・year)] is a value that is specified in Appended Table 2 of MLIT’s 2016 Notification No. 265, and a primary energy consumption under the Building Energy Code per floor area. This coefficient is specified for each room use and each climate zone of a room to be calculated for lighting. Based on Form 4 of room r to be calculated for lighting: ① Building and room uses \(ROOMTYPE_{L,r}\) ) , an applicable coefficient \(a_{SL,r}\) is extracted from Appended Table 2 of MLIT’s 2016 Notification No. 265.

Σ in the formula means the accumulation of primary energy consumptions of all rooms to be calculated for lighting in the input sheet. Specifically, primary energy consumptions of all rooms inputted into “Form 4 Lighting input sheet” are accumulated. For a floor area \(A_{L,r}\), a value inputted into Form 4: ① Room area is used.

10.4 Primary Energy Consumption under the Building Energy Code of Hot-water Supply System

Table 7. Input
Variable Name Description Unit Reference

\(CLIMATEZONE\)

Climate zone of the location of the building subject to evaluation

-

Form 0: ⑤ Climate zone under the Building Energy Code

\(ROOMTYPE_{HW,r}\)

Building and room uses of room r to be calculated for hot-water supply

-

Form 5-1: ① Building and room uses

\(A_{HW,r}\)

Floor area of room r to be calculated for hot-water supply

m2

Form 5-1: ① Room area

\(n_\{HW}\)

Number of rooms to be calculated for hot-water supply

-

Form 5-1: ① Number of total rows for inputting room names

Table 8. Output
Variable Name Description Unit References

\(E_\{SHW}\)

Primary energy consumption under the Building Energy Code of hot-water supply system

MJ/year

Calculate a primary energy consumption of a hot-water supply system, sy\(E_\{SHW}\) [MJ/year], from the following formula.

\[E_\{SHW} = \sum_{r=1}^{n_\{HW}} (a_{SHW,r} \times A_{HW,r} )\]

A coefficient \(a_{SHW,r}\) [MJ/(m2・year)] is a value that is specified in Appended Table 2 of MLIT’s 2016 Notification No. 265, and a primary energy consumption under the Building Energy Code per floor area. This coefficient is specified for each room use and each climate zone of a room to be calculated for hot-water supply. Based on Form 0: Climate zone under the Building Energy Code (\(CLIMATEZONE\) ) and Form 5-1 of room r to be calculated for hot-water supply: ① Building and room uses ([ROOMTYPE_{HW,r}]), an applicable coefficient \(a_{SHW,r}\) is extracted from Appended Table 2 of MLIT’s 2016 Notification No. 265.

Σ in the formula means the accumulation of primary energy consumptions of all rooms to be calculated for hot-water supply in the input sheet. Specifically, primary energy consumptions of all rooms inputted into “Form 5-1 Hot-water supply room input sheet” are accumulated. For a floor area \(A_{HW,r}\), a value inputted into Form 5-1: ① Room area is used.

10.5 Primary Energy Consumption under the Building Energy Code of Elevator

Table 9. Input
Variable Name Description Unit Reference

\(ROOMTYPE_{EV,r}\)

Building and room uses of room r to be calculated for elevator

-

Form 6: ① Building and room uses

\(N_{EV,i}\)

Number of elevators included in elevator system

Number

Form 6: ③ Number

\(L_{EV,i}\)

Load capacity of elevator system

kg

Form 6: ④ Load capacity

\(V_{EV,i}\)

Rated velocity of elevator system

m/min

Form 6: ⑤ Velocity

\(M_{EV,i}\)

Transport capacity coefficient of elevator system

-

Form 6: ⑥ Transport capacity coefficient

\(n_\{EV}\)

Sum of elevator systems

System

Form 6: ② Total rows of equipment names

Table 10. Output
Variable Name Description Unit References

\(E_\{SEV}\)

Primary energy consumption under the Building Energy Code of elevator

MJ/year

Calculate a primary energy consumption of an elevator, \(E_\{SEV}\) [MJ/year], from the following formula.

\[E_\{SEV} = \sum_{i=1}^{n_\{EV}} ( \frac{ L_{EV,i} \times V_{EV,i} \times C_{SEV,i} \times T_{EV,i} \times M_{EV,i} }{860} \times N_{EV,i} ) \times f_{prim,e} × 10^{-3}\]

\(T_{EV,i}\) in the formula is an annual operation time of an elevator system i and specified based on building and room uses of a room r to be calculated for elevator, \(ROOMTYPE_{EV,r}\). The annual operation time of the elevator is assumed to be equal to the annual lighting time of a lighting installation.

A coefficient \(C_{SEV,i}\) is a coefficient for control of standard-set velocity, and deemed to be 1/40. This value is a velocity control efficient when a velocity control method is a variable-voltage and variable-frequency control method (without power regeneration).

Σ in the formula means the accumulation of primary energy consumptions of all rooms to be calculated for elevator in the input sheet. Specifically, primary energy consumptions of all rooms inputted into “Form 6 Elevator input sheet” are accumulated.

\(M_{EV,i}\) in the formula is a transport capacity coefficient of an elevator system i. The transport capacity coefficient is a ratio between a standard 5-minute transport capacity and planned 5-minute transport capacity of an elevator, and is a coefficient to correct a primary energy consumption under the Building Energy Code so that the consumption becomes small apparently if the service level of the elevator is excessively set. The following rule shall apply to the calculation of the transport capacity coefficient.

  • In the case where a building is mainly used for an office etc. or hotel etc., the transport capacity coefficient can be set to 1 if the number of elevator is 2 or less or an elevator is installed to a backyard.

  • In the case where a building is mainly used for those other than an office etc. and hotel etc., the transport capacity coefficient can be set to 1, regardless of the number of elevators.

  • When a planned transport capacity exceeds a standard transport capacity in an office etc. or hotel etc., the transport capacity can be set to 1 if the planned capacity becomes lower than the standard capacity in the number of elevators (Planned number-1).

  • In the case where a building is mainly used for an office etc. and the number of stories in the relevant building is 4 or less or the total of floor areas is 4,000㎡ or less, a value obtained after an average operation time interval ΔT [second] is divided by 30 can be deemed to be a transport capacity coefficient. In the case where the average operation time interval is 30 seconds or more, however, the transport capacity coefficient is set to 1.