Figure 312: Energy to demand factors for four commercial building types Definition of Terms The parameters in the above equation are listed in Table 3111. Table 3111: Commercial Water Heater Fuel Switch Calculation Assumptions Component Type Values Source EFbase, Energy Factor of baseline water Variable Default: 0.904 1 heater Nameplate EDC Data Gathering EFfuel, Energy Factor of installed fossil Variable >=0.67 for Natural Gas 5, EDC Data fuel water heater* and Propane Gathering >=0.495 for Oil EFTankless Water Heater , Energy Variable >=0.82 5 Factor of installed tankless water heater DFfuel, adjust, Fossil Fuel Water Heaters Fixed Storage Water Heaters: 7 Derating Adjustment factor 1.0 Tankless Water Heaters: 0.91 Load, Average annual Load in kBTU Fixed Varies DEER Database Thot, Temperature of hot water Fixed 123 °F 2 Tcold, Temperature of cold water supply Fixed 55 °F 3 HW, Average annual gallons of Use Variable Default: See Table 3110 Calculation EDC Data Gathering EDC Data Gathering EnergyToDemandFactor Fixed 0.000178 4 EFNG, base, Energy Factor of baseline Fixed 0.594 5 gas water heater ResistiveDiscountFactor Fixed 1.0 6 Energy Factors based on Tank Size Federal Standards for Energy Factors are equal to 0.97 -0.00132 x Rated Storage in Gallons. The following table shows the Energy Factors for various tank sizes.
Figure 312: Energy to demand factors for four commercial building types Definition of Terms The parameters in the above equation are listed in Table 3111. Table 3111: Commercial Water Heater Fuel Switch Calculation Assumptions Component Type Values Source EFbase, Energy Factor of baseline water heater Variable Default: 0.904 1 Nameplate EDC Data Gathering EFfuel, Energy Factor of installed fossil fuel water heater* Variable >=0.67 for Natural Gas and Propane >=0.495 for Oil 5, EDC Data Gathering EFTankless Water Heater , Energy Factor of installed tankless water heater Variable >=0.82 5 DFfuel, adjust, Fossil Fuel Water Heaters Derating Adjustment factor Fixed Storage Water Heaters: 1.0 Tankless Water Heaters: 0.91 7 Load, Average annual Load in kBTU Fixed Varies DEER Database Thot, Temperature of hot water Fixed 123 °F 2 Tcold, Temperature of cold water supply Fixed 55 °F 3 HW, Average annual gallons of Use Variable Default: See Table 3110 Calculation EDC Data Gathering EDC Data Gathering EnergyToDemandFactor Fixed 0.000178 4 EFNG, base, Energy Factor of baseline gas water heater Fixed 0.594 5 ResistiveDiscountFactor Fixed 1.0 6 Energy Factors based on Tank Size Federal Standards for Energy Factors are equal to 0.97 -0.00132 x Rated Storage in Gallons. The following table shows the Energy Factors for various tank sizes.
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