## 5.9 B7.6. Large COMMERCIAL Instantaneous, Indirect Gas, and Hot Water Supply Boilers

Energy use for these types of water heaters is given by the following equation.

WHEU = HARL j + PILOT j EFF j × 0.92 j | Equation 38

where

WHEUj = Hourly fuel energy use of the water heater (Btu), adjusted for tank insulation. HARLj = Hourly adjusted recovery load. For independent hot water storage tank(s) substitute

HARLj from Section B3. .

EFFj = Efficiency (fraction, not %). To be taken from CEC Appliance Database or from manufacturers literature. These products may be rated as a recovery efficiency, thermal efficiency or AFUE.

PILOTj = Pilot light energy (Btu/h) for large instantaneous. For large instantaneous water heaters, and hot water supply boilers with efficiency less than 89 percent assume the default is 750 Btu/hr if no information is provided in manufacturer’s literature or CEC Appliance Database.

0.92 = Adjustment factor used when system is not supplying a storage system.