[Equest-users] Heat Recovery from Refrigeration

Rinkesh Shah rinkesh.shah at smithandandersen.com
Wed Nov 23 09:03:48 PST 2011


Thanks to all that replied.

I had two major issues:

1)      Heat recovery on refrigeration only sent the reclaimed heat back into the zones, not the case in my store

2)      Doing a manual calculation using the hourly report would be taking credit where it doesn't exist as building could be in net heating mode as hourly report but AHU on the heat reclaim loop may not be calling for heat (particularly in my case where AHU serving sales area was part of the loop)

The way I ended up working this out was, I modeled the refrigeration as it is without the heat recovery option from the zone details.  This gave me the hourly refrigeration demand from the hourly reports.  Then I modeled the store only with zones that the heat is been recovered into, so that I can get hourly heating demand on for those zones.  Combined the results in a new spreadsheet and took credit for whenever heating was demanded and refrigeration was available.

David: I haven't done the calculation yet on heat reclaimed vs heat rejection from the refrigeration but first look through and it seems to be in the high 60s range.

Smith + Andersen

Rinkesh Shah, B. A. Sc.
Designer - Mechanical
416 487 8151 ext 381
rinkesh.shah at smithandandersen.com<mailto:rinkesh.shah at smithandandersen.com>

4211 Yonge Street Suite 500 Toronto Ontario M2P 2A9
t 416 487 8151 f 416 487 9104  smithandandersen.com

Vancouver  Kelowna  Victoria  Calgary  Edmonton  Toronto  Ottawa  Dubai

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From: Dave Bastow [mailto:dbastow at mcclure-engineering.com]
Sent: Thursday, November 17, 2011 4:09 PM
To: Rinkesh Shah; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] Heat Recovery from Refrigeration

Typically the amount of heat that can be recovered from refrigeration heat reclaim is from 50% to 80% of the total heat of rejection of the refrigeration system.  It varies depending on the outside temperature, which causes the refrigeration system head pressure and associated heat to drop.  Also, the refrigeration load placed on the refrigeration system various with the outdoor ambient air temperature.  If you only have refrigeration cases and walk-ins that are all located inside of a temperature controlled store, then the actual refrigeration load is 70-80% of the typical design BTUH load, because the inside temperature of the building is like maybe 70 degrees F DB and 40 degrees F WB in winter, while the summer design is 75/55.  If you have walk-in coolers that are located outside then the refrigeration BTUH load can be dropped clear down to zero at times, in which cause there is no refrigeration heat reclaim available at all.  You will have to look at your particular situation and use engineering judgment accordingly.

If you model this you should vary the refrigeration load with the outside air temperature and maybe use like 80% of the total heat of rejection for recoverable heat.

David A. Bastow
McClure Engineering, Inc.



From: Rinkesh Shah [mailto:rinkesh.shah at smithandandersen.com]<mailto:[mailto:rinkesh.shah at smithandandersen.com]>
Sent: Tuesday, November 15, 2011 6:06 PM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] Heat Recovery from Refrigeration

Hi eQuesters,

I am modeling a big box store that uses heat reclaim loop to recover energy from their refrigeration load.  The store is to be located in Toronto, Canada.
I was wondering if anyone on these boards has had experience with using heat recovery in the refrigeration section of the zones?

I am hesitant on using the numbers I get from the Heat recovery feature in the refrigeration portion, as I can't see the math behind it.
Help files do not explain how this works and the hourly report doesn't have category specific to heat recovery from refrigeration.

Also if anyone has had experience even with what type of % reduction on the heating, that would be useful too.

Thanks,
Smith + Andersen

Rinkesh Shah, B. A. Sc.
Designer - Mechanical
416 487 8151 ext 381
rinkesh.shah at smithandandersen.com<mailto:rinkesh.shah at smithandandersen.com>

4211 Yonge Street Suite 500 Toronto Ontario M2P 2A9
t 416 487 8151 f 416 487 9104  smithandandersen.com

Vancouver  Kelowna  Victoria  Calgary  Edmonton  Toronto  Ottawa  Dubai

Please reconsider printing this email. Help sustain our resources.

This e-mail message and its attachments contain privileged and confidential information and are intended to be seen and used only by the person(s) to whom it is addressed. Any distribution, copying or dissemination of the information herein by anyone other than the addressee is prohibited. If you have received this message in error, please notify the sender immediately and delete this message.

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