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Engineering ToolBox > Heat Loss from Open Water Tanks
The overall heat loss from an open water tank can be expressed as:
Q = Qevaporation fluid + Qradiation fluid + Qtransmission through walls (1)
The heat loss due to evaporation of water from a surface of an open tank is totally dominant at higher water temperatures. In general heat loss through insulated walls can be almost neglected. Major heat loss can be avoided by covering the surface.
| Water Temperature (oF) | Heat Loss from Liquid Surface (Btu/ft2hr) | Heat Loss Through Tank Walls (Btu/ft2hr) | |||||
| Evaporation Loss | Radiation Loss | Total | Bare Steel Uninsulated | Insulated (inches) | |||
| 1 | 2 | 3 | |||||
| 90 | 80 | 50 | 130 | 50 | 12 | 5 | 4 |
| 100 | 160 | 70 | 230 | 70 | 15 | 8 | 6 |
| 110 | 240 | 90 | 330 | 90 | 19 | 10 | 7 |
| 120 | 360 | 110 | 470 | 110 | 23 | 12 | 9 |
| 130 | 480 | 135 | 615 | 135 | 27 | 14 | 10 |
| 140 | 660 | 160 | 820 | 160 | 31 | 16 | 12 |
| 150 | 860 | 180 | 1040 | 180 | 34 | 18 | 13 |
| 160 | 1100 | 210 | 1310 | 210 | 38 | 21 | 15 |
| 170 | 1380 | 235 | 1615 | 235 | 42 | 23 | 16 |
| 180 | 1740 | 260 | 2000 | 260 | 46 | 25 | 17 |
| 190 | 2160 | 290 | 2450 | 290 | 50 | 27 | 19 |
| 200 | 2680 | 320 | 3000 | 320 | 53 | 29 | 20 |
| 210 | 3240 | 360 | 3600 | 360 | 57 | 31 | 22 |
Heat loss are for open tanks in 60oF still ambient air.
