At Thermaline we work on many custom applications for our customers but one of the applications that comes up frequently is “I want to chill city water from ambient to 40 F to fill my cold liquor tank on the fly”. One of the limiting factors of this application is the glycol chiller. The first question we ask is “what is the max capacity (BTU/HR) of your glycol chiller?”. This is important as this will dictate if we can cool the water down to the desired temp or not, for example:
- City water flow rate: 10 gpm
- Cool from 70 F to 40 F
- Cooling media: 30% glycol at 28 F
- Cooling media flow rate: 20 gpm
- Surface area required: 21.52 sq/ft
- BTU/HR required: 150,044
Now if the glycol chillers max capacity is 75,000 BTU/HR the water temperature outlet is different with the same surface area:
- City water flow rate: 10 gpm
- Cool from 70 F to 55 F
- Cooling media: 30% glycol at 28 F
- Cooling media flow rate: 20 gpm
- Surface area required: 21.52 sq/ft
- BTU/HR required: 75,000
Notice that the surface area remains the same but the max temperature is only 55 F because the chiller can only produce 75,000 BTU/HR, it doesn’t matter how much surface area you add to the heat exchanger the temperature will always stay the same due to the chiller capacity.
There are a couple of solutions if your chiller is undersized:
- Slow the city water flow rate down
- Chill the tank over time to the desired outlet temp
Either way we can come up with a solution for your process, please contact us online today or call (800)767- 6720.
