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I then used Equipment controls as described in the answer above to limit the "free cooling" chiller use based on OAT. I used a condenser pump that does not consume energy. I also included the fan power of the real air cooled consenser to the EIR of the real chiller in order to at least approximate the heat rejection energy use.

I think this solution is adequate given the context but I think eQUEST's frictionless compressor curve is underestimating my cooling energy consumption a bit. I will perform more tests when I have a bit mor time.

Thanks for the input!

Unfortunately, for this project the chiller described above was not selected since there are not enough competitors that offer this product. I no longer have the hours to properly simulate this chiller since they have changed the design with a more standard chilled water plant design and require new results anyway. I ended up simulating the chiller with an electric hermetic centrifugal air cooled chiller with 2 compressors and I used standard curves supplied by equest for frictionless compressors. I copied the chiller and made my new chiller water cooled with an EIR of 0.0001.

I am modelling a new construction in eQUEST that uses a fairly new product that I have not seen before. I was wondering if anyone has any experience modelling this Equipment:

It is a remote air cooled chiller (the chiller is in the basment but the condenser is on the roof 4 floors up). It uses frictionless magnetic bearings, it has 2 compressors and it has an option for water side free cooling which I can't seem to find any documentation on how it works exactly.

In eQUEST, I know that I cannot combine an air cooled chiller with the water side economizer option since I need a condenser loop for the water side economizer and I don't think eQUEST has any built-in performance curves for an air-cooled magnetic centrifugal chiller with 2 compressors.

Does anyone have any ideas of the best way to model this?

I am sure this question has been asked many times before in the onebuilding list but I wanted to have it answered here as well. When ASHRAE 90.1 or MNECB/CNEB ask for a performance rating for a cooling system in SEER, how does one convert this SEER value into an EER to be used in eQUEST?

I know equest uses some formula of conversion in the wizards however where does this formula come from? is it really applicable? I am interested in hearing some thoughts on this subject.

Thanks!

Jason