×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

ERV with added Refrigeration heat recovery

ERV with added Refrigeration heat recovery

ERV with added Refrigeration heat recovery

(OP)
I have that idea to enhance a regular ERV wheel with a refrigeration heat recovery (or rejection in summer). I drew up (attached) how that could look like and wonder if the best and brightest have come across that or have an opinion. Basic idea is:
1. Use ERV wheel to recover some energy and precondition OA
2. Add reversible heatpump to extract heat in EA and warm up OA (Winter operation) or do the opposite in summer (re-cool OA and reject heat to EA).

Potential advantages:
1. potentially better COP of heatpump in cooling since it rejects heat to the EA that is colder than OAT.
2. Potentially high COP to heat OA in winter since we extract heat from relatively warm EA.

Possible issues are:
1. added pressure drop due to condenser/evaporator coils. Obviously an energy simulation needs to determine if there is a net benefit.
2. potential freezing of EA coil if we extract too much heat (I'm in WI)
3. A small heatpump may have less overall efficiency than using a larger more efficient chiller for cooling OA.

Any opinions appreciated. Right now this is a very schematic concept without having done actual calculations for a real-world design.

RE: ERV with added Refrigeration heat recovery

So what do you see as the benefit to linking as you have? An ERW is useful for recovering energy from exhaust air where ventilation is required. It will not heat or cool by itself. A heat pump is is for actually heating or cooling to obtain a desired indoor temperature. There is no direct linkage between the ventilation air flow and the heating or cooling loads so I do not think your proposal is a great idea.

RE: ERV with added Refrigeration heat recovery

(OP)
The heatpump would enhance the ERV wheel recovery, basically increasing effectiveness. Similar could be done by having 2 wheels in a row. so with one wheel 70% recovery, with 2 wheels 90%. Obviously the law of diminishing returns will bite us. The reversing heatpump would do something similar.

But now that I think about it more, 2 wheels probably would be more efficient without compressor, but similar pressure drop.

I wouldn't do a heatpump only, since the ERV will decrease EA humidity and recover humidity for OA. that also would decrease likelihood of freezing EA when the EA coil is in evaporator mode in winter.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources