Performance of lithium bromide refrigeration units
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The performance of the cooling unit in the workshop is poor; the temperature of the chilled water output is as high as 29 degrees, which is far from sufficient to meet the requirements. This set of units has been in operation for almost 8 years now; please help identify any issues that exist. (The unit operation parameters are listed in the attachment.) A high chilled water temperature indicates that the evaporation rate of the refrigerant water is insufficient; with a vacuum level of 1.2 kPa, the water evaporates at around 10 degrees Celsius. In my opinion, some lithium bromide has been lost, which reduces the concentration of its aqueous solution. As a result, more heat is required to concentrate the solution and maintain the circulation of the refrigerant water. So, could increasing the temperature of the hot water solve this problem?
For the proper operation of an absorption chiller, the following factors need to be taken into consideration: 1. Whether there is enough heat source for the refrigerant to evaporate; 2. Whether the vacuum level in the system is sufficient; 3. Whether the temperature of the cooling water is low enough; 4. Whether there are any holes in the heat exchanger tubes; 5. Whether the LIBR concentration is within the operational range... These are some suggestions for reference
Can the problem be analyzed based on the data in the state diagram? The temperature of the hot water and the vacuum level of the system can meet the requirements, there are no holes in the heat exchange tubes, and a cooling water temperature of 28.5 degrees is also sufficient. Is there a specified operating range for the lithium bromide temperature?
The temperature of LIBR... I was wondering if you keep records of past operations; by comparing them, it might be possible to identify the root cause of the problem. Also, let me share my own previous experience: for me, the temperature of the ice water was 10°C, and it dropped to 6°C after exiting the system. In your case, the temperatures are 34/28°C – so there is still a decrease, but perhaps the degree of decrease isn’t sufficient (this can only be determined by looking at past operation records). One more thing to note: aside from what I’ve written above, another important factor is “flow rate”. If the flow rates of hot water, industrial water, and ice water change today, then naturally, the temperature of the resulting ice water will also vary... These are just my thoughts shared for your consideration
The temperature of LIBR... I was wondering if you keep records of past operations; by comparing them, it might be possible to identify the root cause of the problem. Also, let me share my own previous experience: for me, the temperature of the ice water was 10°C, and it dropped to 6°C after exiting the system. In your case, the temperatures are 34/28°C – so there is still a decrease, but perhaps the degree of decrease isn’t sufficient (this can only be determined by looking at past operation records). One more thing to note: aside from what I’ve written above, another important factor is “flow rate”. If the flow rates of hot water, industrial water, and ice water change today, then naturally, the temperature of the resulting ice water will also vary... These are just my thoughts shared for your consideration
You’re absolutely right; there is no measurement of traffic, which is the same as in previous operating conditions. I need to go through the previous records; it’s difficult to find them... Has the cooling efficiency of this lithium bromide unit declined over time? We guarantee that both the cold water tubes and the hot water tubes are cleaned once a month, using high-pressure water.
The issue of attenuation… theoretically, it shouldn’t occur. Another point to note is that the quality of the cooling water is also crucial; there might be internal blockages or holes… We have encountered such problems before, so I’m sharing this information with you. -------------------------------------------------------------------------------------------- The simplest approach is to check if past data shows similar patterns. Also, since I’m not aware of the specifics of your ice-water system, it’s possible that the compressor in that system has been adjusted, resulting in a higher temperature of the water entering the system, or perhaps the heat exchanger used for handling ice water is being used more frequently (due to production requirements or weather conditions). I hope you can resolve this issue soon
A cooling water temperature of 25~30 degrees is acceptable; the vacuum level can also be as it is, and the temperature difference of the cooling water is fine as well. A generator temperature of 80 degrees is also acceptable. But the cooling effect is poor, and I don’t know what the liquid level is in each unit on site. It might be that there isn’t enough lithium bromide as you mentioned, or the refrigerant water has been contaminated by lithium bromide; it’s also possible that octanol needs to be added. In summer, the temperature of the circulating water is high; if there are two units, turn them both on.
The manufacturer has been contacted to go to the site to take samples of lithium bromide, so as to make a judgment later :)
If there are any follow-up results, please share them as well ^^
Okay, let’s exchange knowledge with each other*ha:)