Hello everyone,

Currently I am working on designing a chiller system to provide 30 degree Fahrenheit glycol. Evaporating temperature is about 20 Fahrenheit. The total cooling capacity is 80 tons. I plan to use 9 ten-ton refrigeration systems. One unit is a backup. I would like to use scroll compressors in my design. My questions are:

1. At 20 degree Fahrenheit evaporating temperature, which refrigerant is better, R404 or R507? Which refrigerant is more efficient and easier to maintain?

2. I have two options for the condenser: one option is using remote air cooled condenser. The other one is using water cooled condenser and all the 9 chillers share a cooling tower. I wonder which one is the right way to go.

Please advise if you have any ideas about these questions.

Many thanks