ERV questions

2 posts / 0 new
Last post

A couple questions regarding an energy recovery system that I am trying to
model. The sequence of operations is attached. Basically it is a glycol
loop energy recovery system. Heat is transferred from exhaust to the
glycol loop, then the glycol loop is routed to the AHUs. The glycol pumps
turn off at outside air temperatures between 46F ? 82F.

What is the best way to model this type of energy recovery system?

What is the best way to model the operating schedule?

Any help is greatly appreciated.


*Mike Campbell, E.I.T., LEED AP O+M*
*Sustainability Specialist*
*Sustainable Solutions Corporation*
Office: 610-569-1047

Mobile: 609-923-1743

*Sustainable Solutions Corporation is WBENC and BCorp Certified.*

*This email message and any attachments are for the sole use of the
intended recipient(s) and may contain confidential and privileged
information. Any unauthorized review, use, disclosure or distribution is
prohibited. If you are not the intended recipient, please contact the
sender by reply email and destroy all copies of the original message and
any attachments.*

MikeSSC's picture
Joined: 2012-04-23
Reputation: 1


You can model a runaround loop by selecting a Sensible HX ERV in the Heat Recovery 1 tab of your air-side systems. Convert your pump power to a kW/cfm value and enter it for the ERV-HX-KW/FLOW in the Heat Recovery 2 tab. The static pressure associated with the coils can go on the Heat Recovery 2 tab, or you can zero it out and incorporate it in the air handler fan static, assuming you don?t have separate fans for the runaround loop airside. You could use OA Exhaust DT for the Control Sequences Operation, with an Operating Mode of OA Heat/Cool (or OA Heating ? keep reading). You could pick a compromise OA-EXHAUST-DT value for the different heating and cooling temperature cutoffs, or you could simulate it as heating-only and use the heating OA-EXHAUST-DT value. (You may not get much benefit on the cooling side, depending on where this project is located. The heating OA cutoff of 46F seems low to me especially if you have 3-way valve bypassing glycol. You may have an unusual system if SAT is always 42F.) Read the help menu descriptions of the various controls keywords to come up with the best strategy.


William Bishop, PE, BEMP, BEAP, CEM, LEED AP | Pathfinder Engineers & Architects LLP
Senior Energy Engineer

[ASHRAE Certified logo - greenshot 2] [cid:image002.jpg at 01CF99D3.09D90340]

134 South Fitzhugh Street Rochester, NY 14608

T: (585) 698-1956 F: (585) 325-6005

bbishop at

[earth for signature]Sustainability ? the forest AND the trees.

Bill Bishop's picture
Joined: 2012-02-25
Reputation: 7