#486 Heat Exchanger hotSide coldSide tags

Jay Herron Fri 28 Apr

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 Tue 6 Jun

Hi,

Are there any agreeing/dissenting opinions within the community on this proposal? Should this be pushed into a working group proposal, or rolled in as part of the chiller plant working group?

Thanks!

Paul Bergquist Tue 6 Jun

I think it makes sense and would be a good addition.

Eric Loew Tue 6 Jun

I am in favor of this addition.

Brian Frank Wed 7 Jun

I think given there is a new WG to work on chiller piping and stuff, that we should roll it into that so that its evaluated as a whole

Nathan Rona Sun 18 Jun

Not clear to me what is the condenser water <-> chilled water exchanger. Typically I would think you want either:

  1. to exchange condenser water against cooling tower water, not against chiller water (i.e. the water that is chilled by chiller evaporator.
  2. to exchange heat from primary chilled water circuit to secondary chilled water circuit.

Jay Herron Mon 19 Jun

Nathan,

The condenser water <-> chilled water exchanger situation I was considering is when there is a heat exchanger in parallel with a chiller, to allow waterside economizing when the outside air wet-bulb temperature is low enough that the cooling tower can meet the cooling load without the help of a chiller. That is, this heat exchanger would go from cooling tower water to primary chilled water, and the plant could either use the chiller or the heat exchanger.

Your distinction between condenser water and cooling tower water is interesting. I use condenser water and cooling tower water interchangeably above because haystack currently only defines "condenser" water points for cooling towers, but it's not necessarily true that the water going through a cooling tower has gone through a condenser as well. Seems like something to bring up with the chiller plant working group.

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