Regarding Refrigeration system

[IYYAPPA]

we r using Refregeration fluid 30% glycol and 70 percent water as coolent liquid . Checking if we increase the Glycol water ratio to 40-60 .OR 50-50 GLYCOL WATER ratio. IS t cooling time will reduce .pls suggest. What is plus and minus when we increase the glycol content. Tnanks

 

[Compositepro]

Higher glycol will reduce the heat capacity of the fluid, increase fluid viscosity, and thus lower heat transfer. 50/50 is pretty standard for most applications because it is close to providing the optimum balance of pluses and minuses. Staying under 50/50 is usually better than going over unless you require the lower freezing point. Glycol also costs more than water.

 

[don1980]

For transferring heat, no fluid even comes close to being as good as water. It has an amazing heat capacity. From the perspective of maximizing heat transfer, the ideal concentration of glycol is zero. The only reason glycol is added to coolant systems is because water has the unfortunate property of freezing at 0 degC. Glycol lowers the freezing point of the coolant system so that it can be operated at lower temperatures, without freezing. So, if you need to operate at a lower temperature, then proceed with considering a higher glycol concentration. But, the trade-off will be poorer heat transfer. That's the price you pay for operating at a lower T. To compensate for that, run the coolant at a higher flowrate, or modify the exchanger to acheive a higher heat transfer coefficient. If your system is operating well, and you want to improve the heat transfer, then consider changes to the heat exchangers (to get a higher U value), or consider reducing the glycol concentration if that can be done without getting too close to the freezing point.

 

[georgeverghese]

At higher viscosity, piping friction losses will also increase, so the pump flow (at a given speed) will reduce. As glycol content increases, the viscosity increase will be even more at startup/lower operating temperatures.