Heat exchange area of the coiled tube
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Seeking help: A coil heater needs to be installed in a water tank with a capacity of 170 tons, in order to heat seawater from 15 degrees to and maintain it at 30 degrees. The temperature at the inlet of the coil is 50 degrees. I’m asking experts to help me calculate the heat exchange area of the coil. This post was last edited by fengtao on 2009-4-8 at 16:34
It’s obvious that the conditions are insufficient; the outlet temperature is unknown, and so is the flow rate, so it’s impossible to do the calculation!
I don’t need this; I just need to know what the required heat exchange area for the coil is
It is related; the value of the heat transfer coefficient is directly proportional to the flow rate. To calculate the heat exchange area, one also needs the logarithmic mean temperature difference and the heat load, but with the given conditions, these two values cannot be determined either. Also, have you added an impeller inside the container to enhance heat transfer? I hope you will complete the content.
I would like to point out here that the principle of this type of heater is similar to that of a quick-heating device; by knowing its capacity and calculating the amount of heat required, and then using an appropriate thermal conductivity value, it is possible to determine the area. I encourage everyone to consult relevant information before providing more detailed responses
But since the mass flow rate or volume flow rate of seawater is unknown, it’s not possible to calculate the heat amount; therefore, it’s also impossible to determine S using the formula Q=KxSx△T, right?
Serial Number – Hot Fluid Side; Serial Number – Cold Fluid Side: 1. Hot fluid inlet temperature; 4. Cold fluid inlet temperature; 2. Hot fluid outlet temperature; 5. Cold fluid outlet temperature; 3. Hot fluid flow rate; 6. Cold fluid flow rate. Generally, it is sufficient to provide 5 of these six values, by selecting the fluid side with the most comprehensive set of data for calculating the heat load. It can be seen that the conditions provided by the poster are insufficient, which is why a calculation cannot be done~
These are the only data I have at the moment, and a friend has calculated that the heat exchange area is just over 59
To select the coil for calculation, it is first necessary to determine 1. whether the heat transfer medium inside the coil is hot oil, steam, or water, as well as their specific heat and enthalpy entropy values. 2. Temperature difference of the oil tank or water tank that needs to be heated. 3. The heating area is calculated based on the diameter and length of the coil. 4. Consider the impact of coil length on the temperature reduction of the medium. This approach should be quite clear; everyone can try to work it out
It’s not clear what other restrictions there may be in the tank; it is recommended to design 5 to 8 sets of cylindrical or single-row heating coils. In actual use, it is possible to turn on or off one or two sets depending on the temperature level in order to regulate it. It is also convenient to remove them for maintenance in case of problems, without affecting production.
We have now designed it with a shell-and-tube heater outside the tank, which is used in conjunction with the water inside the tank for circulation. 60 square meters
The conditions are indeed a bit insufficient; for example, are there any measures for forced convection such as stirring? Slot size? Also, what is the flow rate of water in the tank (how much water enters and exits per hour? It seems from the poster’s wording that it’s not an intermittent operation); also, what is the heating medium and what are the requirements regarding the outlet temperature? These conditions must be provided to perform the calculation.
Let me do the calculations: if the temperature of the water taken out is 20 degrees, then after 1.5 hours of heating, the value should be 148 square units; if heating takes 3 hours, it should be 75 square units. Of course, this is assuming that the heat input per unit of time is sufficient. The heat input per unit time must be able to meet 2.55 million calories. If your boiler is to operate at full capacity, it needs to be a boiler with a capacity of at least 50 tons. One could consider not including the heat from surface evaporation here.
I know there is a type of soda heater that uses steam for direct heating, offering high heating efficiency. Size of the equipment unit: diameter of about 1000 mm, height of about 3 m. The water temperature can be automatically adjusted as required, up to 95 degrees. I think it’s more suitable for the original poster’s needs. This post was last edited by lucky1909 on 2009-4-14 09:00]
Does anyone have any small software for heat exchange that they could share with us so we can learn from it?