2022-09-29-REC-min-att - Laserfiche WebLink

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SED Associates Corp Consulting Engineers Option 1 — Standard Electric Water Heater This option would require the use of two (1 -standby) 50 -gallon tanks with 25 kW heating elements/each. The peak demand of each water heaters is 99 GPH, just below the theoretical maximum of 105 GPH. This heater is an immersion type electric resistance heater and is considered to have an efficiency of 100%. Based on the standard calculation for heating water, 25.66 kWH are required. (105 GPH * 8.34 lbs/Gal * (140°F -40°F)) /3413 BTUH/kW = 25.66KWH An estimated annual operation cost based on the provided electrical annual cost $0.23/kWH * 25.66kwh x 833 hours/ yr. =is $4,916.20 annually. The issue with this option is the electric power required to supply them. Each unit requires 66.6 amps of 208/3/60 power, which would go above what is available on the existing service and therefore would require an electrical service upgrade, new panel, and additional circuit wiring for the new water heaters. Approximate Construction Cost: $49,000 (does not include electric utility service upgrades that would include transformer and utility related engineering costs) Option 2 — Package Heat Pump Water Heater This option uses a refrigerant based heat pump with an internal evaporator to either extract/reject heat into the space. The issue with utilizing heat pump water heaters in this application is the space that would be required to house the heaters and the ventilation air that they would need to be ducted to the exterior of the building as the units produce cool air that would reduce the overall efficiency of the units. To produce the same amount of hot water as the existing system two heat pump water heaters with 120 -gallon tanks would be needed. This is due to the lower recovery rate of this type of heater. These heaters are very efficient and have a Co -efficient of Performance (COP) of 4.02. Typical COP range is from 2.0 to 6.0, with 6.0 being the better efficiency. The manufacturer also recommends a minimum of 3,600 FT3 of space per unit for a total of 7,200 FT3. The existing mechanical/electrical space does not have the required volume. This would require that the existing mechanical/electrical space be opened to other areas to get the required volume. Since the men's and women's room are adjacent to this space this is not feasible. In order to determine if this type of water heating system would be a viable option a much more detailed investigative survey and report would need to be made to include an expansion of the building. But based on the current known parameters required, it is our professional opinion that this system is not a viable option. Based on the standard calculation for heating water, 25.66 kWH are required (105 GPH * 8.34 lbs/Gal * (140°F -40°F)) /3413 BTUH/kW = 25.66KWH With a COP of 4.20, the estimated annual operational cost based on the provided electrical cost of $0.23/kWH is $1,171 Approximate Construction Cost: $85,000 (does not include excavation, possible utility company transformer and engineering costs or building modifications necessary to get the volume of space required.)