We would like to create a working group focusing on enhancing chiller plants. This WG will have a specific focus on improving loop tagging and system groupings.

Looking forward to working with everyone, and seeing all the creative solutions to these complicated problems.

-Sean Stackhouse

Hi, I just wanted to repeat a proposal I gave earlier this year that we decided should get rolled into the chiller plant working group. Please see the discussion here: http://project-haystack.org/forum/topic/486

I've quoted the main proposal below as well:

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Hi,

Due to the many different formats of heatExchanger:

• condenser water <-> chilled water
• primary chilled water <-> secondary chilled water
• primary hot water <-> secondary hot water
• secondary hot water <-> tertiary hot water
• and more...

I think it would be very helpful to have tags that generalize the heatExchanger operation among all these situations. I propose that two more tags are included, just for heat exchangers:

• hotSide
• coldSide

This would be the hot/cold side of the heat exchanger when the heat exchanger is in operation. Of course, the other tags should still be present. So for example, on temps in a primary hot water <-> secondary hot water heat exchanger, you may have the points:

• primary hot water hotSide entering temp sensor
• primary hot water hotSide leaving temp sensor
• secondary hot water coldSide entering temp sensor
• secondary hot water coldSide leaving temp sensor

On a condenser water <-> chilled water heat exchanger, you may have the points:

• condenser water coldSide entering temp sensor
• condenser water coldSide leaving temp sensor
• chilled water hotSide entering temp sensor
• chilled water hotSide leaving temp sensor

By using these tags, we no longer need to know the different types of water that the heat exchanger serves, greatly simplifying calculations like hotSide and coldSide dTs or heat exchanger approaches.

Let me know what you think! Thanks!

@Jay Herron - First, I know this is an old topic but I do like the hotSide and coldSide tags. For a waterside economizer HX in a chiller plant the condenser, evaporator, leaving, and entering work. But for CHW HX's in hi-rises to separate pressure boundaries both sides are chilled water so we need the hotSide, coldSide definitions as well as for hot water systems.

On another subject I want to revisit the topic of the tagging conventions used for the common piping between the cooling towers and chillers. I am not sure this is the best place for this post but I do think it is related since the CT’s and Condenser’s are heat exchangers and the hotSide and coldSide tags may be appropriate.

In the discussion here: https://project-haystack.org/forum/topic/35 it seems to hit all around the subject but does not define the condenser water common piping sensors.

In the Chillers documentation here: https://project-haystack.org/doc/Chillers under section 22.2 there is a paragraph that covers “Condenser water between Chillers/Cooling Towers” but does not include the temperature sensors.

Please point me in the right direction if I have missed something in my searches.

Grated that, at least in our markets, typically the Condenser Water Supply refers to the water from the CT’s to the Chillers and Condenser Water Return refers to the water returning back to the CTs. However I have run in to those that see it opposite and are all very passionate about their perspective. In any case there is not a Supply or Return tag defined for chiller plants as we are using entering or leaving which would not be definitive as to which pipe the water is in. So if there is nothing specifically defined I would like to propose one of two options:

1. Use leaving to represent the water leaving the CT’s and entering to represent the water entering the cooling towers in the common pipe; or vice versa depending on popular vote. In either case document this in the “Condenser water between Chillers/Cooling Towers” paragraph of Section 22.2 so it is clearly defined.
2. Use coldSide to represent the water leaving the CT and hotSide to represent the water entering the cooling towers in the common pipe. Document this in the “Condenser water between Chillers/Cooling Towers” paragraph of Section 22.2

Hey everybody - wondering what the status is on this? I don't see any hotSide or coldSide tags published, and was wondering if there was any more discussion that I missed.

Additionally, has anybody proposed a concept for modeling piping loops as its own type of equip? I see this as potentially beneficial in two ways:

1. Ability to create pumpingPlant or something similar and associate it with a particular loop. A pumpingPlant would just consist of multiple pumps, but would allow you to capture more information related to the sequencing of the different pumps within the pumpingPlant. This pumpingPlant would then maybe reference the loop as an equipRef or similar.
2. I feel like it might be easier to understand the relationships between heat exchangers as well.

Curious to others thoughts. Thanks.

Hey guys,

The existing chiller modelling is okay for simple applications, but people have been having trouble when applying it to more complex chiller applications, such as multi-stack chillers, chillers with heat-recovery, or even just those that expose refrigerant data. One of the main issues seems to be that we only model the entire chiller, rather than allowing modeling of the individual chiller components.

As a first-stab at addressing this, I'd like to suggest the following proposal:

• Formalize compressors as equips:
  • compressor-motor is new equip
  • chillerMechanism is changed to compressorMechanism
  • absorption-chiller is now a chiller subtype
  • compresses is added as an equipFunction
• Formalize condensers as equips:
  • condenser is a new heat exchanger subtype
  • condenses is added as an equipFunction
• Formalize evaporators as equips:
  • evaporator is a new heat exchanger subtype
  • evaporates is added as an equipFunction
• Chiller children adjustments:
  • chiller children should be adjusted to reference condenser, evaporator, and compressor points.

I'm interested in any feedback! To get people started, I do have the following question:

• After this, condenser will be quite a loaded tag, denoting an equipment type, as well as a type of water. This is how it is used colloquially though. Does anyone have concerns with this?

Thanks, and let me know what you think!