Method for Calculating Primary Energy Consumption under Japan’s Building Energy Standards (Non-residential Buildings)

3. Evaluation Method of Mechanical Ventilation Equipment

This chapter shows the logic for calculating the primary energy consumption of mechanical ventilation equipment other than air conditioning equipment.

3.1 Introduction

3.1.1 Scope of Application

The mechanical ventilation equipment to be subject to the calculation is of the following types:

Fans primarily used for heat exhaust, dehumidification, and deodorization are defined as mechanical ventilation equipment other than air conditioning equipment, and are subject to calculation.
- Mechanical ventilation equipment installed in a room to be air-conditioned for introducing fresh outside air shall not be considered as mechanical ventilation equipment, but as air conditioning equipment. For example, a total heat exchanger used in combination with a packaged air conditioner, etc., is considered as a part of the air conditioning equipment because it is equipment for introducing fresh outside air, and is subject to calculation for the air conditioning equipment.
- However, for rooms subject to air conditioning that have mechanical ventilation equipment whose main purpose is to exhaust heat, dehumidify, and deodorize (e.g., restrooms and smoking rooms), the part due to fresh outside air should be included in the energy consumption of the air conditioning equipment, and the part due to exhaust heat, etc., should be included in the ventilation energy consumption.
- In the case of cooling the generally ventilated rooms, such as electrical rooms and elevator machine rooms, those types of equipment are considered ventilation equipment and are subject to calculation for ventilation equipment.
Single-phase fans and fans each with a rated output of 0.2 kW or less, as well as fans with a total rated output of less than 5.5 kW, which were not covered by the old standard, shall be included in the calculation under the present standard.
Ventilation equipment that is not in constant operation, such as ventilation equipment in an emergency generator room, or ventilation equipment installed in a conference room to exhaust cigarette smoke (which is not in constant operation due to the balance of supply and exhaust) are excluded from the calculation.
For kitchens, where cooling or heating of supply air is increasingly used, the energy for cooling or heating supply air is excluded from the calculation, and only the fan power of supply and exhaust air for kitchens is included in the calculation.
The dry area in the parking lot is considered as an energy conservation method. If a dry area is provided and the Type 3 ventilation method is used, only the power of the exhaust fan shall be included in the calculation of the ventilation equipment. (The reference values are determined assuming the Type 1 ventilation method.)
If part of the ventilation is provided by natural ventilation, it is assumed that the capacity of the selected ventilation equipment is smaller for this purpose, so no correction is made and the calculation is made using the power consumption of the selected equipment. (Since the reference value is the power consumption assuming there is no natural ventilation, the difference between this value and the design value is the amount of energy saved by natural ventilation.)
When air circulation fan is installed separately from the air supply and exhaust fan to facilitate air movement, if the room in which this fan is installed is an air-conditioned room, the air circulation fan should be accounted for as air conditioning equipment and as a fan power for the air conditioning equipment. If it is a non-air-conditioned room, the air circulation fan should be accounted for as mechanical ventilation equipment and as the fan power of mechanical ventilation equipment.

The following types of mechanical ventilation equipment are excluded from the scope.

Local ventilation equipment in laboratories, etc. (scrubbers, draft chambers, etc.)

3.1.2 Definition of Terms

Mechanical ventilation equipment
Refers to equipment that uses the mechanical power of a fan to supply and exhaust air and to provide ventilation primarily for the purpose of heat exhaust, dehumidification, and deodorization.
Power consumption of mechanical ventilation equipment
The total power consumption of the electric motors and auxiliary modules included in the ventilation equipment when the mechanical ventilation equipment is installed in the building concerned and continuously operated at the planned airflow rate.
Electric motor output of fan
Mechanical rotational energy to operate the fan converted from electrical energy by the electric motor.
Electric motor efficiency
Ratio of motor output to power supplied to the motor (input power).
Load factor
Actual cooling load divided by the required cooling capacity of the air conditioner or package unit. This value is used to calculate the hypothetical power consumption of an alternative ventilation air conditioner.
Coefficients determined according to the control method
Coefficient for considering the energy reduction effect of introducing various controls to improve equipment operating efficiency.

3.1.3 Common Constants

Common constants used in this chapter are listed below.

Table 1. Common Constants
Constant Name	Description	Unit	Value
\(\eta_{m}\)	Electric motor efficiency	-	0.75

3.1.4 Input/Output

The inputs and outputs throughout this chapter are shown in the table below.

Table 2. Input
Variable Name	Description	Unit	Input Sheet
\(ClimateZone\)	Regional category of the location of the building subject to evaluation	-	Form 0: (5) Regional Categories in Energy Conservation Standards
\(BuildingType\)	Building Use	-	Form 3-1: (1) Building Use and Room Use
\(RoomType_{i}\)	Room use of room	-	Form 3-1: (1) Building Use and Room Use
\(Motor_{V,i}\)	Presence or Absence of high-efficiency electric motors	Present/Absent	Form 3-2: (4) Presence or Absence of High-Efficiency Electric Motors or Form 3-3: (9) Presence or Absence of High-Efficiency Electric Motors
\(Inverter_{V,i}\)	Presence or Absence of inverters	Present/Absent	Form 3-2: (5) Presence or Absence of Inverters, or Form 3-3: (10) Presence or Absence of Inverters
\(CtrlType_{V,i}\)	Type of airflow rate control	-	Form 3-2: (6) Airflow Rate Control, or Form 3-3: (11) Airflow Rate Control
\(P_{V,fan,rated,i}\)	Electric motor rated output of ventilation fan	-	Form 3-2: (3) Electric Motor Rated Output
\(RoomType_{Vac,j}\)	Room use of the room to be ventilated by the alternative ventilation air conditioner	-	Form 3-3: (2) Room use of the room to be Ventilated
\(q_{Vac,ref,j}\)	Required cooling capacity of the alternative ventilation air conditioner	kW	Form 3-3: (iii) Required Cooling Capacity
\(\eta_{Vac,j}\)	Heat source efficiency (converted primary energy value) of the alternative ventilation air conditioner	-	Form 3-4: (4) Heat Source Efficiency (Converted Primary Value)
\(P_{Vac,ref,pump,rated,j}\)	Electric motor rated output of the pump attached to the alternative ventilation air conditioner	kW	Form 3-3: (5) Pump Rated Output
\(P_{Vac,ref,fan,rated,j,k}\)	Electric motor rated output of the fan k attached to the alternative ventilation air conditioner	kW	Form 3-3: (5) Pump Rated Output
\(P_{Vac,fan,rated,j,k}\)	Electric motor rated output of the ventilation fan k installed in conjunction with the alternative ventilation air conditioner	kW	Form 3-3: (5) Pump Rated Output
\(Type_{Vac,fan,j,k}\)	Type of the ventilation fan k installed in conjunction with the alternative ventilation air conditioner	-	Form 3-3: (6) Type of Fan
\(V_{Vac,fan,j,k}\)	Design airflow rate of the ventilation fan k to be installed in conjunction with the alternative ventilation air conditioner	m³/h	Form 3-3: (7) Design Airflow Rate

Table 3. Output
Variable Name	Description	Unit
\(E_{V}\)	Design primary energy consumption of mechanical ventilation equipment	MJ/year

3.2 Coefficients Determined According to The Control Method of Fans

The various measures taken to improve the efficiency of fan operation are classified into three categories. Based on the type of the measure taken, defines the values of the coefficient \(f_{V,ctrl,motor,i}\) determined by the presence or absence of a high-efficiency electric motor, the coefficient \(f_{V,ctrl,inverter,i}\) determined by the presence or absence of an inverter, and the coefficient \(f_{V,ctrl,type,i}\) determined by the type of airflow control. Duplicate coefficients cannot be adopted from the same category, and one option must be selected from each category to determine the value.

Based on these values, calculate the coefficients determined according to the control method of the fan.

Table 4. Input
Variable Name	Description	Unit	Reference
\(f_{V,ctrl,motor,i}\)	Coefficient determined by the presence or absence of a high-efficiency electric motor	-	3.2.1
\(f_{V,ctrl,inverter,i}\)	Coefficient determined by the presence or absence of an inverter	-	3.2.2
\(f_{V,ctrl,volume,i}\)	Coefficient determined by the type of airflow control	-	3.2.3

Table 5. Output
Variable Name	Description	Unit	References
\(f_{V,ctrl,i}\)	Coefficient determined according to the control method of the fan	-	3.3, 3.4

The coefficient determined according to the control method of the fan is obtained by the following formula.

\[f_{V,ctrl,i} = f_{V,ctrl,motor,i} \times f_{V,ctrl,inverter,i} \times f_{V,ctrl,volume,i}\]

3.2.1 Adoption of High Efficiency Electric Motors

The input values are referenced to Form 3-2 when evaluating ventilation fans, and Form 3-3 when evaluating alternative ventilation air conditioners (fans installed in conjunction with alternative ventilation air conditioners).

Table 6. Input
Variable Name	Description	Unit	Reference
\(Motor_{V,i}\)	Presence or Absence of high-efficiency electric motors	Present/Absent	Form 3-2: (4) Presence or Absence of High-Efficiency Electric Motors or Form 3-3: (9) Presence or Absence of High-Efficiency Electric Motors

Table 7. Output
Variable Name	Description	Unit	References
\(f_{V,ctrl,motor,i}\)	Coefficient determined by the presence or absence of a high-efficiency electric motor	-	3.2

As shown in the table below, the coefficient corresponding to "Absent" shall be applied when a high-efficiency motor is not used, and the coefficient corresponding to "Present" shall be applied when a high-efficiency motor is used.
If no option is specified (the relevant column on the input sheet is blank), "Absent" shall be assumed to have been selected.

Table 8. Coefficient depending on use/or lack of use of a high-efficiency electric motor
Option \(Motor_{V,i}\)	Corresponding case	Coefficient \(f_{V,ctrl,motor,i}\)
Present	When a low-voltage three-phase squirrel-cage induction motor complying with JIS C 4212 is used	0.95
Absent	Other than above	1.00

Since the motor efficiency is assumed to be 0.75, a high-efficiency motor is assumed to have an efficiency of about 0.79 (\(= \frac{0.75}{0.95}\)).

3.2.2 Adoption of Inverters

The input values are referenced to Form 3-2 when evaluating ventilation fans and Form 3-3 when evaluating alternative ventilation air conditioners (fans installed in conjunction with alternative ventilation air conditioners).

Table 9. Input
Variable Name	Description	Unit	Reference
\(Inverter_{V,i}\)	Presence or Absence of inverters	Present/Absent	Form 3-2: (5) Presence or Absence of Inverters, or Form 3-3: (10) Presence or Absence of Inverters

Table 10. Output
Variable Name	Description	Unit	References
\(f_{V,ctrl,inverter,i}\)	Coefficient determined by the presence or absence of an inverter	-	3.2

As shown in the table below, the coefficient corresponding to "Absent" shall be applied when an inverter is not used, and the coefficient corresponding to "Present" shall be applied when an inverter is used.
If no option is specified (the relevant column on the input sheet is blank), "Absent" shall be assumed to have been selected.

Table 11. Coefficient depending on use/ or lack of use of an inverter
Option \(Inverter_{V,i}\)	Corresponding case	Coefficient \(f_{V,ctrl,inverter,i}\)
Present	When a inverter is installed. It also includes cases where there is no automatic control and the system operates on a fixed frequency.	0.60
Absent	Other than above	1.00

Note that "Present" may also be applied when the rotation speed is not automatically controlled by an inverter and the system operates on a fixed frequency.

3.2.3 Adoption of Airflow Control

Table 12. Input
Variable Name	Description	Unit	Reference
\(CtrlType_{V,i}\)	Type of airflow rate control	-	Form 3-2: (6) Airflow Rate Control, or Form 3-3: (11) Airflow Rate Control

Table 13. Output
Variable Name	Description	Unit	References
\(f_{V,ctrl,volume,i}\)	Coefficient determined by the type of airflow control	-	3.2

As shown in the table below, the coefficient corresponding to "CO and/or CO₂ concentration control" is applied when CO concentration control and/or CO₂ concentration control is used, and the coefficient corresponding to the "Temperature control" is applied when the fan is controlled depending on the inside temperature, and the coefficient corresponding to "Absent" is applied when these controls are not used.
If no option is specified (the relevant column on the input sheet is blank), "Absent" shall be assumed to have been selected.

Table 14. Coefficient depending on the use/ or lack of use of fan control
Option \(CtrlType_{V,i}\)	Corresponding case	Coefficient determined by the type of airflow rate control \(f_{V,ctrl,volume,i}\)
CO and/or CO₂ concentration control	In the case a fan is controlled based on CO and/or CO₂ the concentration in parking lots, etc.	0.60
Temperature control	When a fan is controlled depending on the room temperature in electric room, etc.	0.70
Absent	Other than above	1.00

3.3 Annual Power Consumption of Ventilation Fan

Table 15. Input
Variable Name	Description	Unit	Reference
\(P_{V,fan,rated,i}\)	Electric motor rated output of ventilation fan	kW	Form 3-2: (3) Electric Motor Rated Output
\(f_{V,ctrl,i}\)	Coefficient determined according to the control method of the ventilation fan	-	3.2
\(T_{V,i,r}\)	Annual operating hours of the room r to which the ventilation fan i is connected	hours	B.2

Table 16. Output
Variable Name	Description	Unit	References
\(E_{V,i}\)	Annual power consumption of the ventilation fan	kWh	3.5

\[E_{V,i} = \frac{ P_{V,fan,rated,i} }{ \eta_{m} } \times f_{V,ctrl,i} \times \max_{r}( T_{V,i,r} )\]

where \(\eta_{m}\) is the electric motor efficiency.

3.4 Annual Power Consumption of an Alternative Ventilation Air Conditioner

For the case where an air conditioner or a package unit is used for cooling (using alternative ventilation air conditioner) in a place where ventilation is generally used, such as an electrical room or elevator machine room, obtain the annual power consumption \(E_{Vac,j}\) [kWh] by the following formula.

Table 17. Input
Variable Name	Description	Unit	Reference
\(RoomType_{Vac,j}\)	Room use of the room to be ventilated by the alternative ventilation air conditioner	-	Form 3-3: (2) Room use of the room to be Ventilated
\(q_{Vac,ref,j}\)	Required cooling capacity of the alternative ventilation air conditioner	kW	Form 3-3: (iii) Required Cooling Capacity
\(\eta_{Vac,ref,j}\)	Heat source efficiency (converted primary energy value) of the alternative ventilation air conditioner	-	Form 3-4: (4) Heat Source Efficiency (Converted Primary Value)
\(P_{Vac,ref,pump,rated,j}\)	Electric motor rated output of the pump attached to the alternative ventilation air conditioner	kW	Form 3-3: (5) Pump Rated Output
\(P_{Vac,ref,fan,rated,j,k}\)	Electric motor rated output of the fan k attached to the alternative ventilation air conditioner	kW	Form 3-3: (8) Electric Motor Rated Output
\(P_{Vac,fan,rated,j,k}\)	Electric motor rated output of the ventilation fan k installed in conjunction with the alternative ventilation air conditioner	kW	Form 3-3: (8) Electric Motor Rated Output
\(f_{Vac,ref,fan,ctrl,j,k}\)	Coefficient to be determined according to the control method adopted for fan k attached to the alternative ventilation air conditioner	-	3.2
\(f_{Vac,fan,ctrl,j,k}\)	Coefficient to be determined according to the control method adopted for the ventilation fan k installed in conjunction with the alternative ventilation air conditioner	-	3.2
\(Type_{Vac,fan,j,k}\)	Type of the ventilation fan k installed in conjunction with the alternative ventilation air conditioner	-	Form 3-3: (6) Type of Fan
\(V_{Vac,fan,j,k}\)	Design airflow rate of the ventilation fan k installed in conjunction with the alternative ventilation air conditioner	m³/h	Form 3-3: (7) Design Airflow Rate
\(\theta_{oa,m}\)	Average outside air temperature during intermediate season	℃	B.1
\(T_{V,j,r}\)	Annual operating hours of the room r to which the alternative ventilation air conditioner j is connected	hours	B.2

Table 18. Output
Variable Name	Description	Unit	References
\(E_{Vac,j}\)	Annual power consumption of the alternative ventilation air conditioner	kWh	3.5

\[E_{Vac,j} = ( P_{Vac,ref,j} + P_{Vac,ref,fan,j} + P_{Vac,fan,j} ) \times \max_{r} ( T_{V,j,r} )\]

\[P_{Vac,ref,j} = (\frac{ q_{Vac,ref,j} \times x_{Vac,j} }{ 2.71 \times \eta_{Vac,ref,j} } + \frac{ P_{Vac,ref,pump,rated,j} }{ \eta_{m} } ) \times r_{Vac,ref,j}\]

\[P_{Vac,ref,fan,j} = \sum_{k=1} ( \frac{ P_{Vac,ref,fan,rated,j,k} }{ \eta_{m} } \times f_{Vac,ref,fan,ctrl,j,k} ) \times r_{Vac,ref,j}\]

\[P_{Vac,fan,j} = \sum_{k=1} ( \frac{ P_{Vac,fan,rated,j,k} }{ \eta_{m} } \times f_{Vac,fan,ctrl,j,k} ) \times r_{Vac,fan,j}\]

where \(\eta_{m}\) is the electric motor efficiency.

The annual average load factor of the alternative ventilation air conditioner j \(x_{Vac,j}\) is obtained from the table below.

Table 19. Average annual load factor of the alternative ventilation air conditioner according to the room use of the room to be ventilated
Room use of the room to be ventilated \(RoomType_{Vac,j}\)]	Annual average load factor \(x_{Vac,j}\)
Electric room	0.6
Machine room	0.6
Elevator machine room	0.3
Others	1.00

The operating rate of the alternative ventilation air conditioner j \(r_{Vac,ref,j}\), and the operating rate of the ventilation fan installed in conjunction with the alternative ventilation air conditioner j \(r_{Vac,fan,j}\) are obtained from the table below.

Table 20. Annual operating rate of an alternative ventilation air conditioner and a ventilation fan installed in conjunction with it
Applicable conditions	Annual operating rate of the alternative ventilation air conditioner j \(r_{Vac,ref,j}\)	Annual operating rate of the ventilation fan k installed in conjunction with the alternative ventilation air conditioner j \(r_{Vac,fan,j}\).
When "outside air introduction volume by ventilation fan" is larger than "outside air introduction volume required for outside air cooling"	0.35	0.65
Other than above	1.00	1.00

Here, "outside air introduction volume by ventilation fan" is calculated using the type of ventilation fan k installed in conjunction with the alternative ventilation air conditioner j \(Type_{Vac,fan,j,k}\) and the design airflow rate of the ventilation fan k installed in conjunction with the alternative ventilation air conditioner j \(V_{Vac,fan,j,k }\), as shown in the table below.

Table 21. Outside air introduction volume by a ventilation fan installed in conjunction with the alternative ventilation air conditioner j
Applicable conditions	Outside air introduction volume by ventilation fan
If there is at least one ventilation fan whose fan type is "air supply",	total of "design airflow rates" of ventilation fans whose fan type are "air supply"
If there is no ventilation fan whose fan type is "air supply" and there is at least one ventilation fan whose fan type is "air exhaust",	total of "design airflow rates" of ventilation fans whose fan type are "air exhaust"
Other than above	0

The outside air introduction volume required for outside air cooling \(V_{Vac,oacool,j}\) is obtained by the following formula.

\[V_{Vac,oacool,j} = \frac{ 1000 \times q_{Vac,ref,j} }{ 0.33 \times ( 40 - \theta_{oa,m} ) }\]

The following rules shall be established for determining the required cooling capacity of the alternative ventilation air conditioner j.

If the capacity of the equipment to be installed in the electrical room, etc. is expected to have a capacity margin, the required capacity may be calculated and this value may be entered. For example, if there are installed two units in preparation for a failure and each unit has 100% of required cooling capacity, only the capacity for one unit may be entered. However, the basis for calculating this required capacity must be submitted separately.
For elevator machine rooms, the design heat generation value calculated by the elevator manufacturer, etc. may be used. However, the basis for calculation must be submitted separately.

3.5 Annual Primary Energy Consumption of Mechanical Ventilation Equipment

Calculate the annual primary energy consumption of the mechanical ventilation equipment : \(E_{V}\) [MJ/year].

Table 22. Input
Variable Name	Description	Unit	Reference
\(E_{V,i}\)	Annual power consumption of the ventilation fan	kWh	3.3
\(E_{Vac,j}\)	Annual power consumption of the alternative ventilation air conditioner	kWh	3.4

Table 23. Output
Variable Name	Description	Unit	References
\(E_{V}\)	Design primary energy consumption of mechanical ventilation equipment	MJ/year	-

\[E_{V} = ( \sum_{i=1}E_{V,i} + \sum_{j=1}E_{Vac,j} ) \times f_{prim,e} \times 10^{-3}\]

Annex B (Mechanical Ventilation)

B.1 Average Outside Air Temperature During Intermediate Season

The average outside air temperature during intermediate season \(\theta_{oa,m}\) is defined in the table below for each region category.

Table 24. Input
Variable Name	Description	Unit	Reference
\(ClimateZone\)	Regional category of the location of the building subject to evaluation	-	Form 0: (5) Regional Categories in Energy Conservation Standards

Table 25. Output
Variable Name	Description	Unit	Reference
\(\theta_{oa,m}\)	Average outside air temperature during intermediate season	℃	3.3.2

Table 26. Average outside air temperature during intermediate season
Region	Average outside air temperature during intermediate season \(\theta_{oa,m}\).
Region 1	22.7
Region 2	22.5
Region 3	24.7
Region 4	27.1
Region 5	26.7
Region 6	27.5
Region 7	25.8
Region 8	26.2

B.2 Annual Operating Hours

The annual operating hours of mechanical ventilation equipment are determined for each room use in "Standard Room Use Conditions". Standard room use conditions are specified in the following file, and the applicable schedule is extracted according to the building use and room use of the subject room.

List of building uses and room uses: ROOM_NAME.csv
Reference value of operating hours: ROOM_SPEC_H28.csv

Table 27. Input
Variable Name	Description	Unit	Reference
\(BuildingType\)	Building Use	-	Form 3-1: (1) Building Use and Room Use
\(RoomType_{i}\)	Room use of room	-	Form 3-1: (1) Building Use and Room Use

Table 28. Output
Variable Name	Description	Unit	Reference
\(T_{V,i,r}\)	Annual operating hours of the mechanical ventilation equipment i connected to the room	hours	3.3.1, 3.3.2

Obtain a search key for the database.

Retrieve the search key from ROOM_NAME.csv using the building use \(BuildingType\) and the room use \(RoomType_i\).

Example: If the building use is "office, etc." and the room use is "office Room", the search key is "O-1".

Obtain annual operating hours.

Using the search key, obtain the corresponding value in the "Annual ventilation hours" column from ROOM_SPEC.csv as the annual operating hours.

Example: If the search key is "O-1", the annual operating hours are "0".