Continuous Use Profile
•This example could represent an industrial process which is operated for two continuous shifts a day.
•Hot water is used at a maximum rate of 3.3 gpm or 198 gph. (It is important to establish maximum flow rate and water temperature rise in order to select a heater model.)
•In this example heater recovery is most important as the system for all practical purposes is an instantaneous one. That is, it heats the water at the rate it is being used.
•If a tank type water heater is used, the tank size is minimum . . . just large enough to put the heat into the water.
III.Equipment Performance
Recovery Capacity Tables
Recovery capacity tables are the published results of laboratory tests which establish the ability of a heater to raise the temperature of a given volume of water a certain number of degrees within a given time period.
Recovery tables are prepared for all State commercial water heaters regardless of the type fuel used. In each instance the thermal efficiency of the particular type heater has been taken into consideration.
The tables shown here are representative for the types of heaters produced by State using a variety of fuels. In this publication, for electricity, recovery at 1 kW for various temperature rises is shown. The table can then be used without regard to model number as all electric heaters are considered 100% thermal efficient.
Recovery Capacity |
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| Recovery Capacities Gas Tank Type |
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Calculated at |
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Thermal Efficiency of |
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| Gal. | Btu/Hour |
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@ 94% | Model | Cap. | Nat. & Prop. | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 110 | 120 | 130 | 140 | |
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| 100 | 150,000 | 570 | 427 | 342 | 285 | 244 | 214 | 190 | 171 | 155 | 142 | 131 | 122 | ||
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| Recovery Capacities Electric Tank Type |
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@100% | Kilowatts* | Btu |
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(kW) | Produce |
| 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 110 | 120 | 130 | 140 | |
| 1.0 | 3,413 |
| 13.6 | 10.3 | 8.1 | 6.8 | 5.8 | 5.1 | 4.5 | 4.1 | 3.7 | 3.5 | 3.3 | 3.0 |
*1 KW = 1000 Watts
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