whereFor single-family recirculation systems, hourly pumping energy is fixed as shown in Table B-6.
Table B-6. Single Family Recirculation Energy Use (kWh) by Hour of Day
|
Hour |
Non-Demand Controlled Recirculation |
Demand- controlled Recirculation |
|
1 |
0.040 |
0.0010 |
|
2 |
0.040 |
0.0005 |
|
3 |
0.040 |
0.0006 |
|
4 |
0.040 |
0.0006 |
|
5 |
0.040 |
0.0012 |
|
6 |
0.040 |
0.0024 |
|
7 |
0.040 |
0.0045 |
|
8 |
0.040 |
0.0057 |
|
9 |
0.040 |
0.0054 |
|
10 |
0.040 |
0.0045 |
|
11 |
0.040 |
0.0037 |
|
12 |
0.040 |
0.0028 |
|
13 |
0.040 |
0.0025 |
|
14 |
0.040 |
0.0023 |
|
15 |
0.040 |
0.0021 |
|
16 |
0.040 |
0.0019 |
|
17 |
0.040 |
0.0028 |
|
18 |
0.040 |
0.0032 |
|
19 |
0.040 |
0.0033 |
|
20 |
0.040 |
0.0031 |
|
21 |
0.040 |
0.0027 |
|
22 |
0.040 |
0.0025 |
|
23 |
0.040 |
0.0023 |
|
24 |
0.040 |
0.0015 |
|
Annual Total |
350 |
23 |
Multi-family recirculation systems typically have larger pump sizes, and therefore electrical energy use is calculated based on the installed pump size. The hourly recirculation pump electricity use (HEUP) is calculated by the hourly pumping schedule and the power of the pump motor as in the following equation.
|
HEUP = 0.746 × PUMPk × SCHk,m, k ηk |
Equation 42 |
where
HEUPk = Hourly electricity use for the circulation pump (kWh). PUMPk = Pump brake horsepower (bhp).
ηk = Pump motor efficiency.
SCHk,m = Operating schedule of the circulation pump, see Table B-2. The operating schedule for the proposed design shall be based on user input control method. The standard design operation schedule is demand control.