2.6 Secondary Pump Group¶

2.6 Primary Energy Consumption of Secondary Pump Group¶

The secondary pump group specification is input into Form 2-6 "Secondary Pump Input Sheet", wherein the secondary pump group i should be specified as follows, depending on presence or absence of the input in Form 2-6: (3) Temperature Difference during Cooling and Form 2-6: (3) Temperature Difference during Heating.

1) In the case that values are entered only for Form 2-6: (3) Temperature Difference during Cooling,
Assume that the operation mode of the relevant secondary pump group i is "chilled water pump". The name of secondary pump group i is the same as the string entered in Form 2-6: (1) Secondary Pump Group Name, and the design temperature difference is "Form 2-6: (3) Temperature Difference during Cooling".

2) In the case that values are entered only for Form 2-6: (3) Temperature Difference during Heating,
Assume that the operation mode of the relevant secondary pump group i is "hot water pump". The name of secondary pump group i is the same as the string entered in Form 2-6: (1) Secondary Pump Group Name, and the design temperature difference is "Form 2-6: (3) Temperature Difference during Heating.

3) In the case that values are entered both for Form 2-6: (3) Temperature Difference during Cooling and (3) Temperature Difference during Heating,
There are generated two secondary pump groups: one secondary pump group whose design temperature difference is "Form 2-6: (3) Temperature Difference during Cooling" and whose operation mode is "Chilled Water Pump", and another secondary pump group whose design temperature difference is "Form 2-6: (3) Temperature Difference during Heating" and whose operation mode is "Hot Water Pump". The names of these secondary pump groups should be the same as the string entered in Form 2-6: (1) Secondary Pump Group Name (i.e., there exist two secondary pump groups with the same name in different operation modes).

4) If 1) 2) 3) are not applicable, a calculation error occurs. Either one of Form 2-6: (3) Temperature Difference during Cooling or (3) Temperature Difference during Heating should have a value.

In other words, in case 3), even if there is physically only one secondary pump, the calculation is based on the assumption that there are two separate pumps: one chilled water secondary pump for handling cooling load and another one, a hot water secondary pump for handling heating load.

Table 71. Input
Variable Name	Description	Unit	Reference
\(\Delta \theta_{AC,pump,c,i}\)	Temperature difference of the secondary pump group i during cooling	℃	Form 2-6: (3) Temperature Difference during Cooling
\(\Delta \theta_{AC,pump,h,i}\)	Temperature difference of the secondary pump group i during heating	℃	Form 2-6: (3) Temperature Difference during Heating

Table 72. Output
Variable Name	Description	Unit	References
\(Type_{AC,pump,water,i}\)	Type of water supplied by the secondary pump group	Chilled/hot water	2.6.1

a) If the temperature difference during cooling is positive and there is no temperature difference during heating (not entered),
( \(\Delta \theta_{AC,pump,c,i} > 0 \land \Delta \theta_{AC,pump,h,i} \mbox{ is nothing}\) )

\[ Type_{AC,pump,water,i} = \mbox{chilled water} \]

b) If there is no temperature difference during cooling (not entered) and the temperature difference during heating is positive,
( \(\Delta \theta_{AC,pump,c,i} \mbox{ is nothing} \land \Delta \theta_{AC,pump,ch,i} > 0\) )

\[ Type_{AC,pump,water,i} = \mbox{hot water} \]

c) If the temperature difference during cooling is positive and the temperature difference during heating is positive,
( \(\Delta \theta_{AC,pump,c,i} > 0 \land \Delta \theta_{AC,pump,ch,i} > 0\) )

The calculation is performed twice, assuming that one secondary pump group i has two virtual pumps.

\[ Type_{AC,pump,water,i} = \begin{cases} \mbox{chilled water} & ,(calculation for 1st pump) \\ \mbox{hot water} & ,(calculation for 2nd pump) \end{cases} \]

d) In other cases, the energy consumption of the secondary pump group cannot be calculated.

2.6.1 Secondary Pump Load¶

The load handled by each secondary pump group (secondary pump load) is calculated from the air conditioning load handled by the air handling unit group.

Table 73. Input
Variable Name	Description	Unit	Reference
\(Type_{AC,pump,water,i}\)	Type of water supplied by the secondary pump group	Chilled/hot water	2.6
\(Q_{AC,ahu,c,i,j,d}\)	Daily integrated air conditioning load (cooling) of the air handling unit group j connected to the secondary pump group i on date \(d\)	MJ/d	2.5.5
\(Q_{AC,ahu,h,i,j,d}\)	Daily integrated air conditioning load (heating) of the air handling unit group j connected to the secondary pump group i on date \(d\)	MJ/d	2.5.5
\(Q_{AC,ahu,heat,c,i,j,d}\)	Fan heat generation of the air handling unit group j connected to the secondary pump group i at date \(d\) (during chilled water operation)	MJ/d	2.5.10
\(Q_{AC,ahu,heat,h,i,j,d}\)	Fan heat generation of the air handling unit group j connected to secondary pump group i at date \(d\) (during hot water operation)	MJ/d	2.5.10
\(Q_{AC,ahu,oacool,i,j,d}\)	Load reduction by outside air cooling control of the air handling unit group j connected to the secondary pump group i at date \(d\)	MJ/d	2.5.4

Table 74. Output
Variable Name	Description	Unit	References
\(Q_{AC,pump,i,d}\)	Secondary pump load of secondary pump group i on date \(d\)	MJ/d	2.6.4, 2.7.2

The load handled by each secondary pump group is calculated by totalizing the air conditioning load of the air handling unit groups to which the secondary pump groups supply chilled and hot water, and then adding up the effect of outside air cooling and the heat generated by the air conditioner fans. The subscript j indicates that the calculation should be done for the air handling unit group to which each pump group supplies chilled water.

a) If the secondary pump is a chilled water pump ( \(Type_{AC,pump,water,i} = \mbox{chilled water}\)),

\[ Q_{AC,pump,i,d} = \sum_{j=1} (C_{i,j,d} + H_{i,j,d}) \]

\[ H_{i,j,d} = \begin{cases} Q_{AC,ahu,h,i,j,d} + Q_{AC,ahu,heat,h,i,j,d} - Q_{AC,ahu,oacool,i,j,d} & ,(Q_{AC,ahu,h,i,j,d}>0) \\ 0 & ,(Q_{AC,ahu,h,i,j,d} \leqq 0) \end{cases} \]

The \(C_{i,j,d}\) is calculated as follows, according to the following conditions:

1) If \(Q_{AC,ahu,c,i,j,d}>0 \land Q_{AC,ahu,oacool,i,j,d} \leqq 0\),

\[ C_{i,j,d} = Q_{AC,ahu,c,i,j,d} - Q_{AC,ahu,oacool,i,j,d} + Q_{AC,ahu,heat,c,i,j,d} \]

2) If \(Q_{AC,ahu,c,i,j,d}>0 \land Q_{AC,ahu,oacoo,i,j,d}>0 \land |Q_{AC,ahu,c,i,j,d}-Q_{AC,ahu,oacool,i,j,d} | \geqq 1\),

\[ C_{i,j,d} = Q_{AC,ahu,c,i,j,d} - Q_{AC,ahu,oacool,i,j,d} \]

3) Other than above,

\[ C_{i,j,d} = 0 \]

b) If the secondary pump is a hot water pump ( \(Type_{AC,pump,water,i} = \mbox{hot water}\)),

\[ Q_{AC,pump,i,d} = (-1) \times \sum_{j=1} (C_{i,j,d} + H_{i,j,d}) \]

\[ C_{i,j,d} = \begin{cases} Q_{AC,ahu,c,i,j,d} + Q_{AC,ahu,heat,c,i,j,d} & ,(Q_{AC,ahu,c,i,j,d} < 0) \\ 0 &, (Q_{AC,ahu,c,i,j,d} \geqq 0) \\ \end{cases} \]

\[ H_{i,j,d} = \begin{cases} Q_{AC,ahu,h,i,j,d} + Q_{AC,ahu,heat,h,i,j,d} & ,(Q_{AC,ahu,h,i,j,d} < 0) \\ 0 & ,(Q_{AC,ahu,h,i,j,d} \geqq 0) \\ \end{cases} \]

In the above formula, -1 is used as the multiplier to reverse the sign of the heating load, which has been treated as a negative value, so that it becomes a positive value for the sake of convenience.

In systems where outside air cooling control is enabled, the fan heat generation is assumed to be 0 for days when outside air cooling control is enabled. This is because in a system where outside air cooling is effective, if all air conditioning load is handled by outside air introduction, the apparent air conditioning load is zero. And in this case, if the fan heat generation is added separately, a very small amount of load remains in the calculation, which has a large impact on the energy consumption of the heat source device and the secondary pump. To avoid this, in systems where outside air cooling control is enabled, fan heat generation is ignored for the days when outside air cooling control is effective.

2.6.2 Operating Hours of Secondary Pump Group¶

The operating hours of a secondary pump group is calculated as the total value of the operating hours of the air handling unit groups to which the secondary pump group supplies chilled and hot water.

Table 75. Input
Variable Name	Description	Unit	Reference
\(O_{AC,ahu,i,j,d,t}\)	Operation status of the air handling unit group j connected to the secondary pump group i at date \(d\), time \(t\)	Boolean value	2.5.2

Table 76. Output
Variable Name	Description	Unit	References
\(T_{AC,pump,i,d}\)	Operating hours of the secondary pump group i on date \(d\)	h/d	2.6.4, 2.6.9, 2.6.10
\(O_{AC,pump,i,d,t}\)	Operating status of the secondary pump group i at date \(d\), time \(t\)	Boolean value	2.7.3

The operating hours of the secondary pump group i on date \(d\) \(T_{AC,pump,i,d}\) is calculated by totalizing the operating status of the secondary pump group i at each time during each day, assuming that the secondary pump group i is operating if at least one air handling unit group that supplies chilled/hot water is operating at each time point.

First, calculate the operating status of the secondary pump group i at date \(d\), time \(t\)\(O_{AC,pump,i,d,t}\). For an air handling unit group to which the secondary pump group i supplies chilled/hot water, if \(O_{AC,ahu,i,j,d,t}\) is True for at least one air handling unit group, then \(O_{AC,pump,i,d,t}\) is True, if \(O_{AC,ahu,i,j,d,t}\) is False for all air handling unit groups, then \(O_{AC,pump,i,d,t}\) is False.

The operating hours of the secondary pump group i on date \(d\) \(T_{AC,pump,i,d}\) is calculated by counting the number of hours for which \(O_{AC,pump,i,d,t}\) is True on each day.

2.6.3 Virtual Rated Capacity of Secondary Pump Group¶

The rated capacity of a secondary pump group is defined as the design flow rate multiplied by the design temperature difference.

Table 77. Input
Variable Name	Description	Unit	Reference
\(\Delta \theta_{AC,pump,c,i}\)	Temperature difference of the secondary pump group i during cooling	℃	Form 2-6: (3) Temperature Difference during Cooling
\(\Delta \theta_{AC,pump,h,i}\)	Temperature difference of the secondary pump group i during heating	℃	Form 2-6: (3) Temperature Difference during Heating
\(V_{AC,pump,i,j,rated}\)	Rated flow rate of the secondary pump j belonging to the secondary pump group	m^3/ (h・device)	Form 2-6: (6) Rated Flow Rate
\(N_{AC,pump,i,j}\)	Number of the secondary pumps j belonging to the secondary pump group	Number of devices	Form 2-6: (5) Number of Devices
\(Type_{AC,pump,water,i}\)	Type of water supplied by the secondary pump group	Chilled/hot water	2.6

Table 78. Output
Variable Name	Description	Unit	References
\(q_{AC,pump,i,rated}\)	Virtual rated capacity of secondary pump group	kW	2.6.4, 2.6.5, 2.6.6
\(q_{AC,pump,i,j,rated}\)	Virtual rated capacity of the secondary pump j belonging to the secondary pump group	kW	2.6.5, 2.6.6

The virtual rated capacity of secondary pump j belonging to the secondary pump group i [kW] is obtained from the rated flow rate and design temperature difference by the following formula.

\[ q_{AC,pump,i,j,rated} = \frac{C_w \times V_{AC,pump,i,j,rated} \times N_{AC,pump,i,j} \times \Delta \theta_{AC,pump,i} \times \rho_{w} }{3600} \]

Here, the design temperature difference \(\Delta \theta_{AC,pump,i}\) [K] is the temperature difference between the supply and return temperatures of the chilled and hot water to be supplied to the secondary-side air conditioning system (design value of the supply and return temperature difference).

\[ \Delta \theta_{AC,pump,i} = \begin{cases} \Delta \theta_{AC,pump,c,i} & ,(Type_{AC,pump,water,i} = \mbox{chilled water}) \\ \Delta \theta_{AC,pump,h,i} & ,(Type_{AC,pump,water,i} = \mbox{hot water}) \end{cases} \]

Also, \(\rho_{w}\) is the density of water [kg/m³] and \(C_{w}\) is the specific heat of water at constant pressure [kJ/(kg-K)].

The virtual rated capacity of the secondary pump group i is the sum of the virtual rated capacities of the secondary pumps j belonging to the secondary pump group i.

\[ q_{AC,pump,i,rated} = \sum_{j} q_{AC,pump,i,j,rated} \]

2.6.4 Load Factors of a Secondary Pump Group¶

Calculate the load factor of the secondary pump group i.

Table 79. Input
Variable Name	Description	Unit	Reference
\(Q_{AC,pump,i,d}\)	Secondary pump load of secondary pump group i on date \(d\)	MJ/d	2.6.1
\(T_{AC,pump,i,d}\)	Operating hours of the secondary pump group i on date \(d\)	h/d	2.6.2
\(q_{AC,pump,i,rated}\)	Virtual rated capacity of secondary pump group	kW	2.6.3

Table 80. Output
Variable Name	Description	Unit	References
\(L_{AC,pump,i,d}\)	Load factor of the secondary pump group i on date \(d\)	-	2.6.5, 2.6.6

The load factor of the secondary pump group i on date \(d\) \(L_{AC,pump,i,d}\) is obtained by the following formula.

\[ L_{AC,pump,i,d} = \begin{cases} F\left( \frac{ Q_{AC,pump,i,d} \times T_{AC,pump,i,d} \times \frac{1000}{3600} }{ q_{AC,pump,i,rated} } \right) & ,(T_{AC,pump,i,d} > 0)\\ 0 & ,(T_{AC,pump,i,d} = 0) \end{cases} \]

The function F is defined in the same way as for an air handling unit group as follows.

\[ F(L) = \begin{cases} \frac{floor(L \times 10)}{10} + 0.05 & ,(L > 0) \\ L & ,(\mbox{otherwise}) \end{cases} \]

2.6.5 Number of Secondary Pumps In Operation¶

Calculate the number of pumps operating in the secondary pump group i. The number of pumps in operation varies depending on the Presence or Absence of control over the number of devices.

Table 81. Input
Variable Name	Description	Unit	Reference
\(PumpNumCtrl_{AC,pump,i}\)	Presence or Absence of control over the number of devices in secondary pump group	Present/Absent	Form 2-6: (2) Presence or Absence of Control over the Number of Devices
\(N_{AC,pump,i}\)	Number of secondary pumps belonging to secondary pump group	Number of devices	Form 2-6: (4) Determined from the Order of Operation
\(q_{AC,pump,i,rated}\)	Virtual rated capacity of secondary pump group	kW	2.6.3
\(q_{AC,pump,i,j,rated}\)	Virtual rated capacity of the secondary pump j belonging to the secondary pump group	kW	2.6.3
\(L_{AC,pump,i,d}\)	Load factor of the secondary pump group i on date \(d\)	-	2.6.4

Table 82. Output
Variable Name	Description	Unit	References
\(N_{AC,pump,i,d}\)	Number of operating secondary pumps in the secondary pump group i on date \(d\)	Number of devices	2.6.6, 2.6.8

The calculation formula for the number of pumps operating in a secondary pump group differs depending on the Presence or Absence of control over the number of devices. Here, control over the number of devices is defined as a control in which there are two or more secondary pumps in a secondary pump group and the number of operating pumps is automatically adjusted according to the load.

The number of secondary pumps belonging to the secondary pump group i \(N_{AC,pump,i}\) is the x-th lowest number that has been input. (e.g., if 1st-3rd are input, it will be "3").

a) If the load factor is positive ( \(L_{AC,pump,i,d} > 0\)),

a-1) If control over the number of devices is Absent ( \(PumpNumCtrl_{AC,pump,i} = \mbox{no}\) ),

\[ N_{AC,pump,i,d} = N_{AC,pump,i} \]

a-2) If control over the number of devices is Present ( \(PumpNumCtrl_{AC,pump,i} = \mbox{Yes}\)),

\[ N_{AC,pump,i,d} = \min \{ N │ q_{AC,pump,i,d} < F_{pump,q,i}(N) \land N \leqq N_{AC,pump,i} \} \]

\[ q_{AC,pump,i,d} = q_{AC,pump,i,rated} \times L_{AC,pump,i,d} \]

\[ F_{pump,q,i}(n) = \sum_{j=1}^{n} q_{AC,pump,i,j,rated} \]

b) If the load factor is 0 (\(L_{AC,pump,i,d} = 0\)),

\[ N_{AC,pump,i,d} = 0 \]

The function \(F_{pump,q,i}(n)\) means to totalize the virtual rated capacity up to the n-th secondary pump j belonging to the secondary pump group i. In a-2), the minimum number of operating secondary pumps N that satisfies the load of secondary pump group i on date \(d\) \(q_{AC,pump,i,d}\) is obtained.

2.6.6 Load Factor of Single Secondary Pump¶

Calculate the load factor of the single secondary pump j belonging to the secondary pump group i.

Table 83. Input
Variable Name	Description	Unit	Reference
\(PumpNumCtrl_{AC,pump,i}\)	Presence or Absence of control over the number of devices in secondary pump group	-	Form 2-6: (4) Determined from the Order of Operation
\(PumpCtrlType_{AC,pump,i,j}\)	Flow rate control method for the secondary pump j belonging to the secondary pump group	-	Form 2-6: (8) Flow Rate Control Method
\(q_{AC,pump,i,rated}\)	Virtual rated capacity of secondary pump group	kW	2.6.3
\(q_{AC,pump,i,j,rated}\)	Virtual rated capacity of the secondary pump j belonging to the secondary pump group	kW	2.6.3
\(L_{AC,pump,i,d}\)	Load factor of the secondary pump group i on date \(d\)	-	2.6.4
\(N_{AC,pump,i,d}\)	Number of operating secondary pumps in the secondary pump group i on date \(d\)	Number of devices	2.6.5

Table 84. Output
Variable Name	Description	Unit	References
\(L_{AC,pump,i,j,d}\)	Partial load factor of the secondary pump j belonging to the secondary pump group i on date \(d\)	-	2.6.7

If there is no control over the number of devices, it is calculated as follows:

a) If there is no control over the number of devices,

a-1) If the flow rate control method for all secondary pumps j is "rotational speed control",

\[ L_{AC,pump,i,j,d} = L_{AC,pump,i,d} \]

a-2) Other than the above,

\[ L_{AC,pump,i,j,d} = \begin{cases} 1.0 & ,(L_{AC,pump,i,d} \leqq 1.0) \\ 1.2 & ,(otherwise) \end{cases} \]

If there is control over the number of devices, it is calculated as follows.

b) If there is control over the number of devices,

b-1) If the flow rate control method of secondary pump j is "constant flow rate control",

\[ L_{AC,pump,i,j,d} = \begin{cases} 1.0 & ,(L_{AC,pump,i,d} \leqq 1.0) \\ 1.2 & ,(otherwise) \end{cases} \]

b-2) Other than the above,

\[ q_{AC,pump,i,d,CWV} = \sum_{j} \{q_{AC,pump,i,j,rated} \mid j \leqq N_{AC,pump,i,d} \land C_{i,j} \} \]

\[ q_{AC,pump,i,d,VWV} = q_{AC,pump,i,rated} \times L_{AC,pump,i,d} - q_{AC,pump,CWV,i,d} \]

\[ N_{AC,pump,i,d,VWV} = {\mathrm{count}} \{ j \mid j \leqq N_{AC,pump,i,d} \land \lnot C_{i,j} \} \]

\[ q_{AC,pump,i,j,d} = \frac{ q_{AC,pump,i,d,VWV} }{ N_{AC,pump,i,d,VWV} } \]

\[ L_{AC,pump,i,j,d} = \frac{ q_{AC,pump,i,j,d} }{ q_{AC,pump,i,j,rated} } \]

where \(C_{i,j}\) is a boolean value that is True if the flow rate control method of the secondary pump j in the secondary pump group i is a "constant flow rate control", and False if it is a "variable flow rate control".

In b-2), \(q_{AC,pump,i,d,CWV}\) is the total amount of heat [kW] handled by the secondary pump j whose flow rate control method is a "constant flow rate control", \(q_{AC,pump,i,d,VWV}\) is the total amount of heat [kW] handled by the secondary pump j whose flow rate control method is a "rotational speed control", and \(N_{AC,pump,i,d,VWV}\) is the number of operating secondary pumps j whose flow rate control method is a "rotational speed control".

2.6.7 Coefficients Determined by Flow Rate Control Method¶

Calculate the coefficient determined by the flow rate control method.

Table 85. Input
Variable Name	Description	Unit	Reference
\(L_{AC,pump,i,j,d}\)	Load factor of the secondary pump j belonging to the secondary pump group i on date \(d\)	-	2.6.6
\(PumpCtrlType_{AC,pump,i,j}\)	Flow rate control method for the secondary pump j belonging to the secondary pump group	-	Form 2-6: (8) Flow Rate Control Method
\(L_{AC,pump,i,j,min}\)	Minimum flow rate ratio of the secondary pump j belonging to the secondary pump group	%	Form 2-6: (9) Minimum Flow Rate Ratio during a Variable Flow Rate

Table 86. Output
Variable Name	Description	Unit	References
\(f_{AC,pump,i,j,d}\)	Coefficient determined by the flow rate control method of the secondary pump j belonging to the secondary pump group i on date \(d\)	-	2.6.8

The minimum flow rate ratio of the secondary pump j in the secondary pump group i \(L_{AC,pump,i,j,min}\) should be \(L_{AC,pump,i,j,min} = 100\) if the flow rate control method of the secondary pump j is a "constant flow rate control".

The coefficient determined by the flow rate control method of the secondary pump group i \(f_{AC,pump,i,j,d}\) is calculated by the following formula.

a) If \(L_{AC,pump,i,j,d}>1.0\),

\[ f_{AC,pump,i,j,d} = 1.2 \]

b) If \(L_{AC,pump,i,j,d}=0\),

\[ f_{AC,pump,i,j,d} = 0 \]

c) If \(0 < L_{AC,pump,i,j,d} < \frac{L_{AC,pump,i,j,min}} {100}\),

\[ f_{AC,pump,i,j,d} = F_{AC,pump,i,j}\left(\frac{L_{AC,pump,i,j,min}}{100}\right) \]

d) If \(\frac{L_{AC,pump,i,j,min}} {100} \leqq L_{AC,pump,i,j,d} \leqq 1.0\),

\[ f_{AC,pump,i,j,d} = F_{AC,pump,i,j}(L_{AC,pump,i,j,d}) \]

where the function \(F_{AC,pump,i,j}(L)\) is a fourth-degree polynomial expressed as the following formula.

\[ F_{AC,pump,i,j}(L) = a_{i,j} \times L^{4} + b_{i,j} \times L^{3} + c_{i,j} \times L^{2} + d_{i,j} \times L + e_{i,j} \]

The coefficient \(a_{i,j},b_{i.j},c_{i,j},d_{i,j},e_{i,j}\) is the coefficient representing energy consumption characteristic of secondary pump j and is determined by the flow rate control method \(PumpCtrlType_{AC,pump,i,j}\). If \(PumpCtrlType_{AC,pump,i,j}\) is not specified, the control method is assumed to be "constant flow rate control".

Flow rate control method \(PumpCtrlType_{AC,pump,i,j}\)	\(a_{i,j}\)	\(b_{i,j}\)	\(c_{i,j}\)	\(d_{i,j}\)	\(e_{i,j}\)
Constant Flow Rate Control	0	0	0	0	1
Rotational Speed Control	0	0	0	1	0

This energy consumption characteristic value was defined based on the results of a field survey conducted by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) in its 2011 and 2012 Building Standard Improvement Promotion Project, Survey Item 36: "Empirical Evaluation of Energy Saving Effects through Optimal Control of Air Conditioning Systems, etc." Here, the rotational speed control is defined as the control in which the pump rotational speed is automatically adjusted by an inverter or other means. If the rotational speed control is used, the minimum flow rate ratio (ratio to rated flow rate) should be set, and if the load factor falls below this minimum flow rate ratio, the load factor should be the coefficient at the minimum flow rate ratio. The reason for assuming that 1.2 times the rated power consumption is consumed during overload, is the same for the airflow rate control method for air handling unit group.

2.6.8 Power Consumption of Secondary Pump Group¶

Calculate the power consumption of secondary pumps belonging to the secondary pump group.

Table 87. Input
Variable Name	Description	Unit	Reference
\(N_{AC,pump,i,d}\)	Number of operating secondary pumps in secondary pump group i on date \(d\)	Number of devices	2.6.5
\(f_{AC,pump,i,j,d}\)	Coefficient determined by the flow rate control method of the secondary pump j belonging to the secondary pump group	-	2.6.7
\(E_{AC,pump,i,j,rated}\)	Rated power consumption of the secondary pump j belonging to the secondary pump group	kW/device	Form 2-6: (7) Rated Power Consumption
\(N_{AC,pump,i,j}\)	Number of the secondary pumps j belonging to the secondary pump group	Number of devices	Form 2-6: (5) Number of Devices

Table 88. Output
Variable Name	Description	Unit	References
\(E_{AC,pump,i,d}\)	Power consumption of the secondary pump group i on date \(d\)	kW	2.6.9, 2.6.10

The power consumption of the secondary pump group i on date \(d\) \(E_{AC,pump,i,d}\) is obtained by the following formula.

\[ E_{AC,pump,i,d} = \sum_{j=1}^{N_{AC,pump,i,d}} \left( E_{AC,pump,i,j,rated} \times N_{AC,pump,i,j} \times f_{AC,pump,i,j,d} \right) \]

2.6.9 Heat Generation of Pumps in the Secondary Pump Group¶

Calculate the heat generation of the pumps in the secondary pump group.

Table 89. Input
Variable Name	Description	Unit	Reference
\(E_{AC,pump,i,d}\)	Power consumption of the secondary pump group i on date \(d\)	kW	2.6.8
\(T_{AC,pump,i,d}\)	Operating hours of the secondary pump group i on date \(d\)	Hour/day	2.6.2

Table 90. Output
Variable Name	Description	Unit	References
\(Q_{AC,pump,heat,i,d}\)	Heat generation of a pump in the secondary pump group i on date \(d\)	MJ/d	2.7.2

The heat generation of the secondary pump is calculated by the following formula.

And \(f_{pump,heat}\) is the heat generation ratio of the pump.

\[ Q_{AC,pump,heat,i,d} = f_{pump,heat} \times E_{AC,pump,i,d} \times T_{AC,pump,i,d} \times 3600 \times 10^{-3} \]

2.6.10 Annual Primary Energy Consumption of a Secondary Pump Group¶

Calculate the annual primary energy consumption of a secondary pump group.

Table 91. Input
Variable Name	Description	Unit	Reference
\(T_{AC,pump,i,d}\)	Operating hours of the secondary pump group i on date \(d\)	h/d	2.6.2
\(E_{AC,pump,i,d}\)	Power consumption of the secondary pump group i on date \(d\)	kW	2.6.8

Table 92. Output
Variable Name	Description	Unit	Reference
\(E_{AC,pump,i}\)	Annual primary energy consumption of the secondary pump group	MJ/year	2.8

The annual primary energy consumption of a secondary pump group \(E_{AC,pump,i}\) is calculated by the following formula.

And \(f_{prim,e}\) is the coefficient that converts one kilowatt-hour of electricity into thermal energy.

\[ E_{AC,pump,i} = E_{AC,pump,e,i} \times f_{prim,e} \]

\[ E_{AC,pump,e,i} = \sum_{d=1}^{365} \left( E_{AC,pump,i,d} \times T_{AC,pump,i,d} \right) \times 10^{-3} \]