What is the reason for the high water temperature at the outlet of the water cooling tower?

Why does the chiller keep tripping due to the high water temperature at the outlet of the water cooling tower? Has there been any change in the water temperature at the inlet and outlet of the water cooling tower? It’s normal for the filler to get dirty; of course, the cooling effect will be weaker if the amount of nitrogen contaminants is low. The nitrogen pollution pressure is acceptable; if there is a blockage inside the cold box, the pressure in the upper tower will change. It’s possible to check this by comparing it with previous data.

Because chillers are equipped with interlock protection, they shut down once the temperature exceeds 15 degrees. The outlet temperature of the water cooling tower hasn’t changed much; it’s just relatively high. A nitrogen pollution pressure of around 12–13 is generally appropriate. I wonder if it’s because the water isn’t clean. Have you experienced such a situation due to unclean water? There is no good way to determine the cause at the moment. Is there a problem with the water cooling tower equipment itself?

Generally, chillers do not have such interlock protection; when the inlet water temperature is high, the load on the chiller increases, but the designed water temperature is not achieved. What I mean is to compare whether there is a change in the water temperature at the inlet and outlet of the water cooling tower; since the pressure of contaminated nitrogen is lower than before, the pressure inside the tower will change as well. It’s also possible that dirty water is the cause of this situation. You mentioned that there is a lot of discoloration in the packing inside the water cooling tower, which may have affected the heat exchange between water and air. However, in this case, the opposite occurs: scaling has formed in the packing of the water cooling tower, resulting in high pressure in the system, and this in turn leads to high pressure in the tower. The solution adopted was to reduce the flow rate of water from the chiller units and direct it to the air-cooled tower, while also recycling some of the chilled water. Although the flow rate from the chiller units was reduced, the temperature was lowered, and this approach proved effective. It is recommended to try disabling the interlock protection that triggers shutdown at 15 degrees Celsius.

For supplementation and as a recommendation when parking, open the manhole at the top of the water cooling tower to inspect and clean the sieve plates； When the blockage is severe, water mist will spray out from above the water cooling tower ； The water filter at the inlet of the chiller’s condenser also needs to be cleaned. Additionally, there are issues with the installation quality of the tray plates, which results in uneven water distribution. Attention should also be paid during inspection. Water quality issues should be the main reason. It is highly recommended to check the water cooling tower strainer.

1. Check whether the water temperature at the inlet of the water cooling tower is rising. If the workload on subsequent workstations increases, the temperature of the circulating water rises. 2. Observe whether the temperature difference between the inlet and outlet of the water cooling tower has decreased. If the temperature difference is the same (compared to previous records), then the heat exchange efficiency of the air-cooled tower remains unchanged, ruling out blockages inside the cold box. 3. Is the flow rate of polluted nitrogen normal? If the flow rate is low, the heat exchange efficiency will be poor. 4. Check whether there is severe loss of the refrigerant (ammonia or Freon) inside the freezer. If the refrigerant level decreases, it should be replenished immediately.

Additional note: 5. If there are suspicions regarding the quality of the circulating water, the water supply department can be asked to test a range of parameters such as the turbidity of the circulating water.

Thank you all for your replies. We will clean the packing tomorrow, and then discuss it with you again. Additionally, I came up with a method – I’m not sure if it will work – to draw the air from the outlet of the air-cooled tower during driving from the water-cooled tower; since this air is at high pressure, I want to see if the water temperature will drop. If it does, it means that the pressure of the contaminated nitrogen is the cause of the high water temperature. Everyone, do you think this method is feasible? ? ? I hope everyone can come up with your solutions? If it’s truly feasible, you can give it a try. Last edited in this post by HH3010 on 2009-2-8 at 12:55.]

It’s probably not the case that the nitrogen waste channel is blocked; if that were the case, all your other readings would be incorrect as well. First of all, it would be impossible to establish a balance and the air separation unit couldn’t operate. The problem lies in the opening degree of the valve at the inlet of the circulation pump (I’m not sure whether you use valves at the inlet or outlet for control). In general, the return water from the air cooling tower is controlled by automatic valves based on the water level, while the valve at the pump regulates the amount of water in the circulation system – if this amount is too high or too low, the temperature will rise； I think the blackening of the filler is due to dirty air, the contaminants washed down by the air-cooling tower.

Upstairs, the filler is in the water cooling tower. Furthermore, the blockage is suspected to be in the subcooler or heat exchanger, not in the upper or lower towers; so how can there be an imbalance?

The packing in the water cooling tower is Baffle Rings, and the lower part of the packing has turned black

Our air separation unit has just been started up, and it has now stopped due to this issue. The pressure of dirty nitrogen at the inlet of the water cooling tower remains low at 6-7 KPA, and the temperature at the inlet of the circulating water is consistently 32°. Furthermore, does a low dirty nitrogen pressure necessarily mean that the amount of dirty nitrogen has decreased? Why? This post was last edited by HH3010 on 2009-2-8 16:28.]

It has little to do with water quality issues; the key problem is that the temperature of the water exiting the cooling tower is very high. Most likely, there are blockages in the cooling tower, which reduces the heat exchange efficiency. It is recommended to open the access panels and conduct a thorough inspection

Low pressure does not necessarily mean low flow rate. On the contrary, the lower the pressure, the greater the flow rate, right?

Is there any issue with the packing installation? Is the resistance at an acceptable level? I’ve encountered problems in the past with the packing in air-cooled towers – the manufacturer tried to save money by not providing proper guidance, and the tower was placed in a horizontal position before loading; coupled with improper packing methods, this led to the packing breaking down, increased resistance, and no effective heat exchange. You should definitely investigate the issues related to the packing installation in your air-cooled system. It’s unlikely that the pressure of the polluted nitrogen gas will be exactly the same as what’s specified in the design; as long as your air separation unit can operate in balance, there should be no major problems. Last edited by super1 on 2009-2-9 16:15

1. Check the power of the chiller; if there is sufficient headroom, adjust the chiller’s settings to lower the temperature of the chilled water leaving the chiller； 2. Adjust the amount of contaminant nitrogen to reduce the temperature of the water cooling tower ； 3. Short-circuit air is supplied to the water-cooled tower for operation, ensuring its cooling efficiency. Compare the operating conditions of the 4 air separation units before and after to determine whether the main heat exchanger channels are blocked ；

1. The water distributor is clogged; the pH value of the water is greater than 9. 2. Is there a flange connection behind where the cooling water enters the air-cooling tower, which could cause a disruption in the flow and lead to reduced water distribution by the distributor as well as uneven distribution of water. 3. Check whether the inlet temperature before the cooling water pump is normal – it should generally be below 15 degrees. 4. If the temperature of the gas entering the air-cooling tower is too high, it can cause the packing at the bottom to deform, increasing resistance. 5. Is there a check valve installed at the outlet of the cooling water entering the air-cooling tower? 6. Severe scaling on the packing can increase resistance and reduce the efficiency of heat exchange (this situation occurs quite rarely).