Air-cooled, frictionless centrifugal chiller with free cooling option in eQUEST

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Hello all,

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

It is a Smardt remote air cooled chiller (the chiller is in the basement 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. I don't have enough information from the equipment spec sheets to model my own curves either.

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

Thanks!

[cid:image001.jpg at 01D0609C.777C3DA0]

Jason Ng_ing. jr. M.Sc.A., LEED green associate
jng at bpa.ca | www.bpa.ca | t: 5143833747x2813

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This spreadsheet was sent to me last year from a Smardt rep for a 90 ton Smardt chiller. It may help.

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Tom that is for a water cooled unit and not applicable to an air cooled
condenserless model.

Jason in a previous position I ran the turbocor testing lab and built all
the compressor maps/ dll?s. I also wrote the original Smardt selection.

If the manufacture is providing both the chiller section and the remote
condenser section then they have the ability to provide the data for you. If
this is a third party condenser with unknown characteristics the model is
going to be harder to create. You might want to just model a stock packages
air cooled unit from their catalog and apply heavy safety factors.

I would suggest making contact with the factory and have them provide
whatever runs you need, make an estimate of the saturation temperature loss
in the discharge and liquid line and bias the model appropriately to reflect
the loss.

If they want the sale and your model will influence the transaction they
should be open to assisting.

Regards Philip

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Hi Philip,

Thanks for the info. Unfortunately, this wouldn't solve the issue of the free-cooling option for this chiller. Even if I could get enough information from the manufacturer to properly model the performance curves, I would have to put an air-cooled chiller in eQUEST which would eliminate the possibility of modelling the free cooling within the software. At this stage of the project, the amount of time it would take to do external calculations based on the hourly results from eQUEST to model the free cooling just wouldn't be worth it.

I was hoping someone could offer a quicker, easier, more approximate solution to take all the characteristics of the chiller into account. Of course, understanding that there will probably have to be some big approximations to be able to do it all.

I had tried simply modelling the chiller with a water cooled condenser but using standard air cooled condenser curves and with a fluid cooler with the approximate power consumption of the condenser fans of the chiller. This way I could add a free cooling option within eQUEST however I feel like this is grossly overestimating my cooling consumption since I am not taking into account the improved part load characteristics of the dual magnetic compressors.

Any other ideas?

Thanks!

[cid:image002.jpg at 01D06228.1A68BCF0]

Jason Ng_ing. jr. M.Sc.A., LEED green associate
jng at bpa.ca

De : Philip Kennedy [mailto:philip at kiltechcontrols.com]
Envoy? : 17 mars 2015 19:21
? : 'Tom Mickley'; Ng, Jason; equest-users at lists.onebuilding.org
Objet : RE: [Equest-users] Air-cooled, frictionless centrifugal chiller with free cooling option in eQUEST

Tom that is for a water cooled unit and not applicable to an air cooled condenserless model.

Jason in a previous position I ran the turbocor testing lab and built all the compressor maps/ dll's. I also wrote the original Smardt selection.

If the manufacture is providing both the chiller section and the remote condenser section then they have the ability to provide the data for you. If this is a third party condenser with unknown characteristics the model is going to be harder to create. You might want to just model a stock packages air cooled unit from their catalog and apply heavy safety factors.

I would suggest making contact with the factory and have them provide whatever runs you need, make an estimate of the saturation temperature loss in the discharge and liquid line and bias the model appropriately to reflect the loss.

If they want the sale and your model will influence the transaction they should be open to assisting.

Regards Philip

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