Pre-cooling system for air cooled chillers

[farahghanem]

Dear colleagues,

I am trying to model a pre-cooling system for an air cooled chiller. The available feature in the CWL menu adds a pre-cooling system to the return water, however, there is a different kind of pre-cooling system that I have in mind. Which is a condenser pre-cooling system. The following website explains it: http://multigensolutions.com.au/pre-cooling-system/

My approach to this is to lower my design outdoor air DBT and WBT from the heat rejection tab (instead of 41 C down to 29ish C). This would result the chiller COPs at design conditions to exceed the rated conditions and hence improve its performance.

I am wondering if this approach is correct, and how would the chiller work in part-load? My main concern is that although we raised the COP by inputting appropriate design temperatures with the system used, when running the simulation, the chiller would be observing the simulation weather file temperatures, as opposed to what the pre-cooling system is providing it.

Please advice!

Thanks!

[farahghanem]

I don't know what I was thinking, that is obviously not the best approach. I believe the correct way would be to use part-load curves as cooling source and set-up temperature dependencies for the COPs. The data to input into the curve need to be provided by the chiller and precooler suppliers.

Basically I would adjust the part-load efficiency by whatever factor the precooler calculations show.

Anyone has any further ideas or can confirm my method?

Appreciate any help.

[farahghanem]

bump...

While I think I know generally what should be done as explained above (edit curves), it doesn't seem like something easy to do for me. Any help is appreciated.

Cheers!