Table : Water Heater Temperature Setback Assumptions Component Unit Values Source , Energy Factor of water heater Fraction EDC data collection 1 Default: Electric Storage= 0.904 HPWH= 2.0 , value of water heater tank, EDC Data Gathering Default: 8.33 50 gal. EDC Data Gathering , value in Surface Area of water heater tank, Default: 24.99 Table 2119 , Fraction Electric Storage: 0.97 2, 3 Thermal efficiency of electric heater element (equiv. to COP for HPWH) HPWH: 2.1 , Volume of hot water used per day, in gallons/day 7.32 4, 5, 6, 7, 8 gallons Thot_i , Temperature setpoint of water heater °F 9 EDC Data Gathering initially Default: 130 °F EDC data collection 10 Thot_f , Temperature setpoint water heater after setback Default: 123 ETDF , Energy To Demand Factor (defined 0.00008047 11 above) Note: The new Federal standards that go into effect 4/16/2015 will be incorporated into this measure in the 2016 TRM. These can be viewed at: The energy savings and demand reductions are prescriptive according to the above formulae. However, some values for common configurations are provided in Table 264 below. Table : Energy Savings and Demand Reductions Demand Tank Size Energy Type Reduction (˚F) (gallons) Savings () Electric 50 8.33 24.99 10 0.97 0.904 151 0.0125 Storage Electric 50 8.33 24.99 5 0.97 0.904 76 0.0063 Storage HPWH 50 8.33 24.99 10 2.1 2.0 69 0.0057 HPWH 50 8.33 24.99 5 2.1 2.0 35 0.0029
Table : Water Heater Temperature Setback Assumptions Component Unit Values Source , Energy Factor of water heater Fraction EDC data collection Default: Electric Storage= 0.904 HPWH= 2.0 1 , value of water heater tank, EDC Data Gathering Default: 8.33 , Surface Area of water heater tank, EDC Data Gathering Default: 24.99 50 gal. value in Table 2119 , Thermal efficiency of electric heater element (equiv. to COP for HPWH) Fraction Electric Storage: 0.97 HPWH: 2.1 2, 3 , Volume of hot water used per day, in gallons gallons/day 7.32 4, 5, 6, 7, 8 Thot_i , Temperature setpoint of water heater initially °F EDC Data Gathering Default: 130 9 Thot_f , Temperature setpoint water heater after setback °F EDC data collection Default: 123 10 ETDF , Energy To Demand Factor (defined above) 0.00008047 11 Note: The new Federal standards that go into effect 4/16/2015 will be incorporated into this measure in the 2016 TRM. These can be viewed at: The energy savings and demand reductions are prescriptive according to the above formulae. However, some values for common configurations are provided in Table 264 below. Table : Energy Savings and Demand Reductions Type Tank Size (gallons) (˚F) Energy Savings () Demand Reduction Electric Storage 50 8.33 24.99 10 0.97 0.904 151 0.0125 Electric Storage 50 8.33 24.99 5 0.97 0.904 76 0.0063 HPWH 50 8.33 24.99 10 2.1 2.0 69 0.0057 HPWH 50 8.33 24.99 5 2.1 2.0 35 0.0029
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