How to determine whether the water volume in the circulating water system is sufficient
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As the title suggests, I’m facing a problem: the cooling efficiency of the circulating water system is poor now. The heat exchange area has already been increased, and assuming that area is sufficient, if the cooling effect is still poor, could it be due to an insufficient amount of cooling water? Or are there other issues that haven’t been identified yet? PS: Given the complexity of the system’s piping network, I personally think that the total amount of cooling water available is insufficient. But this is just a guess on my part; I’d like to determine this through calculations. I hope everyone can offer some guidance. Could you suggest what data I should use for these calculations?
It can be determined based on the inlet and outlet water temperatures; if the temperature difference is lower than before, it indeed means that the cooling effect is poor. The first reason is insufficient cooling water volume; it is necessary to switch the heat exchanger and check for any blockages. The second reason is scaling in the heat exchanger pipes; it is necessary to coordinate the circulating water system and adjust the chemical dosing strategy to improve scale control.
Personal opinion: It’s probably not a problem with the water volume; have you considered the operating capacity of the fans and pumps?
Generally speaking, when the heat exchanger is enlarged, the water volume also needs to be increased accordingly; otherwise, the temperature difference between the inlet and outlet water cannot reach its optimal level, that is, the difference is not maximal. In addition to increasing the circulating water volume, it is of course necessary to increase the cooling area and the amount of induced air as well; all these parameters are related to it. If the heat exchange efficiency is poor despite no changes to the heat exchangers or cooling equipment, it indicates that either scaling has occurred, in which case the amount or formula of the scale inhibitor should be adjusted immediately, or it is due to algae, requiring an increase in the amount of the algaecide or a change in its type.
Check the supply and return water temperatures. Poor cooling performance may be due to a reduced cooling capacity of the cooling tower for the return water, which leads to an increase in the feedwater temperature and thus a decline in cooling efficiency. It could also be that scaling in the heat exchanger reduces its heat exchange efficiency.
In a circulating water system, if the cooling fans are running at full capacity yet the outlet water temperature is higher than the design value, it can be determined that the amount of water circulating in the system is insufficient.
The method on the 6th floor is very simple; is it workable?
According to what the poster said, even though the heat exchange area has been increased, the cooling effect remains poor. This indicates that either there isn’t enough water flow in the cooling water, or it’s necessary to lower the temperature of the circulating water; it’s also important to check whether there are any problems with the cooling tower fans. But generally, once a circulating water system is established, the cooling efficiency declines; the most common issue is scaling of the system, which requires cleaning, and the formulation of the chemicals used for treating the circulating water needs to be adjusted!
What type of cooling tower are you using?
Try turning on both the water pump and the fan at full speed; if the temperature still doesn’t drop, then there is a problem. Question 1: A design issue – the circulation volume was set too low, but this is generally unlikely. 2. The system is likely to be scaled. 3. The inside of the heat exchanger is blocked by debris.
In my opinion, it is necessary to consider the temperature factor; if the heat exchange area is sufficient but the water temperature at the outlet of the heat exchanger rises significantly, then it can be concluded that there is not enough water flow. If the heat exchange area is insufficient, the temperature drop on the process side is generally small, and the outlet water temperature on the water side also does not become too high.
Judge it based on the temperature difference. Provided that there are no problems with the heat exchange equipment.
Compare the temperature difference between the inlet and outlet water; if it doesn’t change much, it is likely a process issue or scaling problem.
According to the design specifications for circulating cooling water treatment GB50050, the volume of an open-type circulating cooling water system should be less than 1/3 of the hourly circulating water volume. However, if the circulation rate is too low and the water flow is too slow, it will also affect the cooling efficiency.
It might be due to the water temperature in the circulation system being too high; the temperature can be lowered.
It’s not clear why the heat exchange area has increased – was new equipment installed, or has the load on the system changed? If that’s the case, it is recommended that you calculate the circulating water volume. Otherwise, it is recommended that you check the operation of the system: temperature, flow rate, pressure, and also the scaling in the pipelines mentioned earlier, as all of these can reduce the cooling efficiency.
The poster said the cooling effect is poor; if they’re referring to water, then what is used for circulating water cooling? Cooling towers. Then the one on the sixth floor must be a professional one. I said it was ambiguous. Why? The original poster mentioned increasing the heat exchange surface area, yet the cooling effect wasn’t good; here it probably refers to a poor heat exchange effect, which results in an inability to lower the temperature in industrial applications. (Because I really can’t see what connection there is between water cooling and the heat exchange surface.) At the designed flow rate (when the cooling tower’s capacity to cool water is not an issue), if heat transfer is poor, it can be certain that scaling or sludge accumulation has occurred on the water side of the heat exchange equipment. The original poster might want to take a look: under the normal designed water flow rate, if the water temperature is low and the temperature difference is small, it is likely that scaling and sludge are causing poor heat exchange. If the water temperature is high and the temperature difference is small, then there is a problem with the cooling tower’s capacity; check whether the fans are running at full speed. In both of these cases, the heat exchange efficiency will decrease
This question is too complicated; the original poster didn’t explain the situation clearly
Personally, I don’t think it’s a problem with the amount of cooling water; there is likely some blockage in the pipes
I think we should start from several aspects: first, compare the inlet and outlet water temperatures before and after increasing the heat exchange area; second, check the inlet water temperature of the cooling tower; third, if you feel that the water volume is not sufficient, you can start more water pumps and then compare the cooling effect after increasing the system pressure. Identify where the specific problem lies, and then address it.
6# qzwenwen: In a circulating water system, if the cooling fans are running at full capacity yet the outlet water temperature is higher than the designated value, it can be determined that the amount of water circulating in the system is insufficient.