#742 Refrigerant/Compressor proposal for Chiller/Split System support

Jay Herron Tue 1 Oct 2019

I'd like to make a proposal the improve the taxonomy of chillers, and add in compressors, evaporators, condensers, and split-systems. If this needs a new working-group I'm happy to lead it up.

Breifly, I'd like to propose the following:

  1. A new refrigLoop top-level equipment type is introduced, of which chiller is a subclass
  2. splitSystem is created as another sub-type of refrigLoop
  3. condenser and evaporator are created as equipment sub-types of heatExchanger
  4. compressor is created as a sub-type of motor
  5. chillerMechanism & chillerMechanismType are replaced by compressorMechanism and compressorMechanismType

Functionally, chiller and splitSystem will operate in much the same way as ahu and fan, actuator, or coil. That is to say, typically chiller or splitSystem will include condenser, evaporator, and compressor points under a single equipment. However, if needed, these components can be split out into sub-equipment themselves.

Some questions I have:

  1. How should chiller-absorption be handled, since it's not a compressor feature and therefore wouldn't belong in compressorMechanism. Should we change chillerMechanism options to absorption and compression?
  2. Should coolingTower be a sub-type of evaporator? How would this interact with the heatExchanger tag?
  3. refrigLoop feels clunky, when we haven't defined loops for other fluids. Any ideas on generalizing loops? I almost feel like that's a much larger task that may be best to attack separately.

These changes will formalize some important concepts like condensers, evaporators, and compressors into the taxonomy, allow modeling of split-system equipment, and improve support for multi-stage chillers and air compressor equipment.

Please let me know your thoughts!!

Richard McElhinney Wed 2 Oct 2019

Hi Jay,

I love your enthusiasm for the topic and I agree this is something that is needed. However could I put in a cheeky request?

Could you wait a few days before forming a new working grouo?

I have an article on this very topic coming out in the new Haystack magazine that is about to be published and it deals with some of the ideas you have put forward here and a lot more.

At Conserve It, where I work, we have been modelling chillers and machines in software for over 10 years and have learnt a lot. In my article I am proposing a new model that takes into account chillers and their sub-equip types as well as other machines such as heat recovery machines and heat pumps.

After the article is published me and my team would be more than happy to collaborate on a Working Group. Some of my team are very keen to be involved.

Feel free to contact me offline if you have any questions in the meantime.

Cheers, Richard

Jay Herron Wed 2 Oct 2019

Sure, Richard. I appreciate any input you guys may have, and of course your company's experience and knowledge are appreciated. I look forward to seeing your article, and collaborating in a working group afterward to push the Haystack standard forward.

Jay Herron Tue 21 Jan 2020

Hey Richard, any interest in pushing this forward now that the article has had some time to settle?

If you'd like to outline your recommendations, I'd be happy to combine them with my prior proposal and try to get something out for review from a wider audience.

Richard McElhinney Tue 21 Jan 2020

Hi Jay,

Sure thing, perhaps we could connect offline to discuss before coming back with a recommendation to the community. You can reach me at richard.mcelhinney@conserveitiot.com.

Josiah Johnston Mon 10 May

Hi everyone,

I'm curious about the status & progress of modeling split systems. Can you please send an update and links to relevant articles? I'm having trouble finding the article in question..

Best regards

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