The hourly energy use for instantaneous
gas or oil water heaters is given by Equation
34, where the nominal rating is multiplied by 0.92 to reflect the
impacts of heat exchanger cycling under real world load patterns.The hourly energy use for instantaneous
gas or oil water heaters is given by Equation
34, where the nominal rating is multiplied by 0.92 to reflect the
impacts of heat exchanger cycling under real world load patterns.
|
WHEU = HARLj j EFj × 0.92 |
|
where |
| |
|
WHEUj |
= |
Hourly fuel energy use of the water heater (Btu). |
|
HARLj |
= |
Hourly adjusted recovery load. |
|
EFj |
= |
Energy factor from the DOE test procedure (unitless). This is taken from manufacturers’ literature or from the CEC Appliance Database. |
|
0.92 |
= |
Efficiency adjustment factor |