We would like to propose the following Haystack expansion for heat recovery systems (systems composed of a fluid loop that exchanges heat between exhaust and outside air sections):

New or Adjusted Tags

Equip tags

• heatRecovery - Denotes a heat recovery equipment or heat recovery water point
• heatRecoveryRef - A ref pointing to the associated heat recovery equip. Generally used with ahu or exhaust fan equips.

Point tags

• heatRecovery - Denotes a heat recovery equipment or heat recovery water point
• coilHeatRecovery - Denotes air points that are associated with the heat recovery coil in either the ahu or exhaust equipment.
• exhaust - Expanded from its current definition to also denote heat recovery water that is going to or leaving the coil in the exhaust air stream.
• outside - Expanded from its current definition to also denote heat recovery water that is going to or leaving the coil in the AHU outside air stream.

Example Points

heatRecovery equip points

• exhaust entering heatRecovery water temp
• exhaust leaving heatRecovery water temp
• outside water heatRecovery entering temp
• outside water heatRecovery leaving temp
• heatRecovery water bypass valve
• heatRecovery pump status

ahu equip points

• coilHeatRecovery leaving air temp
• heatRecovery entering water temp
• heatRecovery leaving water temp

exhaust equip points

• heatRecovery entering water temp
• heatRecovery leaving water temp
• coilHeatRecovery leaving air temp
• coilHeatRecovery entering air temp

I'm excited to hear peoples' thoughts!!

I support these recommendations with the one exception that we avoid compound tag names like: coilHeatRecovery.

I think separate tags for heatRecovery and coil is more flexible.

There are also heat recovery wheels and this could be modeled with a "wheel" tag and not require yet another "wheelHeatRecovery" tag.

There are many times I add a coil tag to be able to represent temperatures behind a preheat coil, cooling cool, heating coil, etc. I would like to see "coil" added as a standard tag.

@Jay ----I like your use of exhaust and outside. I also have a few other comments, but it might be useful if we talked on the phone for a few minutes to make sure I understand your intent. You can contact me at [email protected]

@Paul ---- I like your recommendation for coil as a separate/standard tag.

@Paul, thanks for the feedback! I also like the idea of having coil as a separate tag.

@Denis, I'd be happy to discuss with you. I'll reach out offline.

Following a good discussion with Denis, I'd like to submit an updated proposal. The main changes and clarifications are:

• Adjusting coilHeatRecovery to heatRecovery. I like the idea of a separate coil tag, but I think it should be left to another proposal because its implications reach far beyond heat recovery systems.
• heatRecovery entering air temp on the ahu is not present in the example points because I interpreted it as equivalent to the outside air temp. If this is not necessarily true, I'm fine with adding this point to the ahu example points.
• heatRecovery water temp points are duplicated on the ahu / exhaust and heatRecovery equips to support cases where a heat recovery loop connects multiple exhaust streams or AHUs.

Here's the new proposal:

New or Adjusted Tags

Equip tags

• heatRecovery - Denotes a heat recovery equipment or a point associated with the heat recovery coil in an ahu, heatRecovery, or exhaust system.
• heatRecoveryRef - A ref pointing to the associated heat recovery equip. Generally used with ahu or exhaust fan equips.

Point tags

• heatRecovery - Denotes a heat recovery equipment or a point associated with the heat recovery coil in an ahu, heatRecovery, or exhaust system.
• exhaust - Expanded from its current definition to also denote heat recovery water that is going to or leaving the coil in the exhaust air stream.
• outside - Expanded from its current definition to also denote heat recovery water that is going to or leaving the coil in the AHU outside air stream.

Example Points

heatRecovery equip points

• heatRecovery exhaust water entering temp
• heatRecovery exhaust water leaving temp
• heatRecovery outside water entering temp
• heatRecovery outside water leaving temp
• heatRecovery pump cmd
• heatRecovery water bypass valve

ahu equip points

• heatRecovery air leaving temp
• heatRecovery water entering temp
• heatRecovery water leaving temp

exhaust equip points

• heatRecovery air entering temp
• heatRecovery air leaving temp
• heatRecovery water entering temp
• heatRecovery water leaving temp

Let me know what you think!

This looks good Jay. I think the best way move it forward is to have a standing AHU working group that "owns" this proposal and all other AHU proposals (I'm assuming this is specific to AHUs?). Would you be willing to lead that working group? Or does someone else want to champion it? If so then lets create new forum post titled "AHU Standing WG" and reference this proposal. Then it will probably take a little bit of massaging to get this into the AHU chapter (and we can figure out plan with pending type system rework)

Hi! the idea of this topic seems very useful. I just wanted to check if it is approved because I couldn't see this heatRecovery tag anywhere. Thanks

a heat recovery system has 4 sides. what is the suggestion for tagging them? is this right?

entering primaryLoop

leaving PrimaryLoop

entering secondaryLoop

leaving secondaryLoop

Hey Ashkan,

Nothing has been standardized on this - the only formal support for heat recovery systems that I know of is heatWheel. Informally, I use the proposed tags above to model run-around-loop heat recovery systems, so under that system the four sides you're mentioning would be:

• heatRecovery exhaust water entering temp
• heatRecovery exhaust water leaving temp
• heatRecovery outside water entering temp
• heatRecovery outside water leaving temp

Please do realize that there is some disagreement within the community and these tags are likely not what the final solution will be. This comment was a great reminder about this proposal though - I'm planning to add it to our next AHU working group discussion.

Thanks!