IBPSA Boston Chapter kickoff meeting

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Dear colleagues and friends in the Greater Boston Area,

As recently announced to this list, we will be launching an IBPSA-USA
chapter for the greater Boston area next Tuesday, February 22nd, from
8:00 AM to 9:30 AM, at the Harvard Design School which is located at 48
Quincy Street in Cambridge. We will be in Gund Hall Room 112, right
next to the cafeteria. We have a panel of speakers from IBPSA USA as
well as local practitioners and scholars who will provide short
overviews of the current state of building performance simulation within
their area of expertise as well as their vision of where BPS should be
heading and what role the local chapter of IBPSA USA could play to
facilitate this process. In the future we intend to organize quarterly
morning meetings during which speaker pairs from industry and academia
will share their results and activities related to BPS. We need your
input and I hope that hope many of you in the Boston area will find the
time to join us next Tuesday. We also have a number of board openings to

Autodesk is very kindly providing coffee and pastries for the event
which we will have to order by tomorrow at noon. So, please make time,
join us and RVSP now at www.ibpsa-boston.com

Warm regards,

Christoph Reinhart, Dr. Ing.

Reinhart, Christoph's picture
Joined: 2011-10-02
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The EER of WWHP can vary from 11.8 to 23.3 depending on the water temperature
returning from the well field. Can Trace or Equest model this?

I'm starting to design a lot of geo-thermal systems, but I can't model the
well field performance, my models accuracy will be greatly affected.

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Jeurek's picture
Joined: 2010-10-07
Reputation: 0


eQuest can model a geoexchange field but there are a lot of limitations. There is an upper limit on field size and there are limitations on the plant side as well. You can use a single zone heat pump configuration or try to setup a loop-to-loop heat pump, but that can get nasty.

To do an accurate model of a geoexchange system you'd probably be best off using TRNSYS and/or a manufacturer's software. TRNSYS has a steep learning curve and the manufacturer's software can be a bit of a black box with hidden factors of safety, etc. Also TRNSYS can only do cylindrical fields, which can be a significant limitation in some instances.

I've never tried a geoexchange model in Trace.

Getting an accurate heat pump performance curve can be challenging. To make a good performance map in TRNSYS takes about 50 selections at varying inlet temperatures on both evaporator and condenser sides. Then there is a whole other ball of wax called controls.

What we typically do is model the building and get hourly loads in eQuest. And then transfer the loads to TRNSYS to be modeled there with a field sized using manufacturer software. It's unfortunately a bit of a convoluted process to right size a field, but it is worth it as design costs are much less than construction costs for large fields.

If you have a small field you probably could get away with getting loads out of Trace or eQuest and placing it in the manufacturer's software.

Sorry for the long convoluted answer.

Good luck!


Fred Betz's picture
Joined: 2011-09-30
Reputation: 0

Equest has a model for both the loop field & the heat pump that take into
account the entering and leaving water temperatures from the loop field.
You need to make sure that the correct performance curves are selected for
the heat pump.

Morgan Heater, PE

Morgan Heater's picture
Joined: 2011-10-02
Reputation: 0