![]() We have 8GPM of water with an inlet temperature of 65☏ and outlet temperature of 95☏. ΔT = temperature rise in ☏ (The difference between the minimum inlet temperature and maximum outlet temperature.) The KW equation incorporates a 20% safety factor, allowing for heat losses of the jacket and piping, variation in voltage and wattage tolerance of the elements. This equation is based on the criteria that there is no vaporization occurring in the heater. When calculating the power required to heat a material flowing through a circulation heater, the KW equation shown below can be applied. Step 1: Convert 3000 CFM at 25 psia and 350° F to CFM at standard conditions using the above formula:ģ000 x (25/15) x = 3333 SCFMĬalculations for circulation heater applications The CFM at a higher pressure (P) and inlet air temperature (T) may be calculated as follows:Ī drying oven, operating at 25 psia (10 psi gauge pressure), recirculates 3000 CFM of air per minute through a heater which raises its temperature from 350 to 400° F. Note that CFM is given at standard conditions (SCFM): 80° F and normal atmospheric pressure of 15 psi. Once the volume of air in standard cubic feet per minute (SCFM) and the required temperature rise in ☏ (ΔT) are known, the required kilowatt rating (KW) of the heater can be determined from the following formula: If the volume of the tank is stated in cubic feet (ft³) the formula looks like this: To begin we need to convert the gallons of water to pounds: The tank has R-4 insulation and the minimum ambient temperature is 0☏. KWmaintain = (A x (1/R) x ΔT(☏) x SF)/3412Ī 4’ x 6’ x 12’ tank with 1800 gallons of water needs to be heated from 60☏ to 95☏ in 3 hours. ΔT = difference between the process set point (end) temperature and the start temperature The KW calculation to raise the temperature is as follows:Ĭp = Specific Heat, see examples in the chart Additionally we’ll need the weight of the material to be heated, the specific heat of the material and the time required to heat the material from its start temperature to its end temperature. The KW calculation to raise the temperature of a material in a tank (heat-up) starts with the same information required in the maintain application. ΔT = difference between the process set point temperature and lowest ambient temperatureĪ 42’ diameter x 40’ tall crude oil tank with R-6 insulation needs to be maintained at 75☏ given a minimum ambient temperature of 10☏.Ī = (2 x 3.14 x 21 x 40) + (2 x 3.14 x 21²) See the chart below for typical examples.Use 0.5 as the R-value of an uninsulated steel tank.To calculate the KW required to maintain the temperature of a tank you will need to determine the tanks surface area, process temperature to be maintained, minimum ambient temperature and the R-value of the insulation.Ī (ft²) = 2 x Īfter determining the tanks surface area the maintain KW can be calculated as follows: You can also visit our website and utilize our online calculator look for the free calculator link near the top of the page. Below are the calculations for each application. When selecting a heater for tank heating application you must first determine whether the application requires that the temperature be maintained or if the temperature needs to be raised. 873 Series Quick Ship SCR Control Panel.873 Series Quick Ship Contactor Control Panel. ![]() Some final, 'steady state' temperature will be achieved when:īut it can't be found merely from input power. This loss of heat prevents the temperature of the object from rising and rising, so is actually much desired. This energy loss may be intended (cooled car engines e.g.) or circumstantial (your processor loses energy in a variety of way) This would seem to indicate that if we just keep up the power we could reach any temperature, right?Īs it happens, also with your processor, most heated object do not only receive energy, they also lose energy. Where $T$ is the temperature in $^\circ\text$$ So I researched the net and found that 1 watt is about 1.16194 C
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