[Equest-users] DOAS with Enthalpy Wheel and Heat Pipe

[Fleming, Joe]

It is my understanding that, the "horseshoe" or "run around" heat pipe is not an option an eQuest.  Model your enthalpy wheel as normal and then what I usually do here is set my supply air up higher than 55 and eliminate humidity control.
A runaround heat pipe will effectively reduce the capacity of the initial system (assuming this is at the start of design).  It will then provide free reheat to a point.  So if you have a system with a 10 ton load at peak, a passive run around heatpipe might bring that load down to 8.5 tons (about 15% from the reduction in delta T across the coil), it will then give you free reheat so you don't overcool the space and have to energize dehumidification systems or electric or hot gas reheat.
So, by raising your supply air temperature from 55 to 62 in equest (or whatever your heatpipe temp rise is), your unit will have a reduced capacity and will not overcool the space (humidity will not be modeled correctly).

This is how I do it, and I am eager to see how others model passive run around or horseshoe type heatpipes.

Good luck!

Joe Fleming
E.I., LEED AP BD+C, BEMP
Mechanical Engineer II

TLC Engineering for Architecture
Your 2030 Challenge Partner

800 Fairway Drive, Suite 250
Deerfield Beach, FL 33441-1816

phone:

954-418-9096

fax:

954-418-9296

direct:

954-418-4591

website:

www.tlc-engineers.com<http://www.tlc-engineers.com/>


[cid:image001.gif at 01CBD1A8.0FB37080]<http://www.tlc-engineers.com/>

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Steve Burley
Sent: Sunday, February 20, 2011 4:31 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] DOAS with Enthalpy Wheel and Heat Pipe

I am trying to model a DOAS with two forms of heat recovery. An enthalpy wheel on the inlet to the AHU and a heat pipe arranged in a "horseshoe" arrangement around the DX cooling coil. Has anyone got any similar examples I can use?

Thanks,

Steven Burley
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20110221/45d3034c/attachment-0002.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.gif
Type: image/gif
Size: 5272 bytes
Desc: image001.gif
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20110221/45d3034c/attachment-0002.gif>