[Equest-users] Water to water geothermal heat pump / Radiators / No cooling / Natural ventilation

[Nick Patsos]

First of all thank you all for your answers once again.

I tried some things, starting by changing the approach of the Loop-to-loop
heat pump to the 2-Pipe loop as you proposed, which is obviously better,
but I don't seem to get the snap temperature correct. There will always be
some unmet cooling or heating hours. Is there a way to minimize these ?

As far as the Systems 9/10 are concerned, I read that these are applicable
only for heated storage or similar spaces. My spaces are normally occupied
and conditioned/ventilated with mechanical or natural ventilation. It is
projected that no cooling will be needed since there is no summer operation
of the building, but since this is not absolutely certain, the approach to
have baseline cooling in the proposed case is better-suited (to my view).
My question is, to what extent should baseline cooling be the 'same' for
proposed ? Should kW/cfm for fans be the same as well?

Regarding ground source heat pumps, do you know if there are any available
curves ready to use in eQuest ?

Also, any thoughts for the implementation of natural ventilation? I've read
about solutions using other software, but unfortunately my knowledge is
limited to eQuest. Is it possible to prove savings to LEED for natural
ventilation using eQuest only ? Has anyone attempted this?

Best regards
Nick Patsos
Mechanical Engineer


On 7 February 2014 18:13, Hall, Brendan <BHall at karpinskieng.com> wrote:

>  A couple things to add:
>
>
>
> -          There is also a heat pump chiller type that you can try, as
> opposed to zone WSHP  units. Either way make sure to get good performance
> data so you can generate custom performance curves, since the standard
> conditions for rating geothermal heat pumps are different than WSHP or air
> cooled heat pumps. There are some default curves in equest for WSHPs that
> are a good starting point though.
>
>
>
> -          It is likely that the engineer ran GLHEPRO or some other
> sizing calculation on the geo loop so you may be able to get good ground
> temperatures from there.
>
>
>
> -          With a two pipe loop it is always important to have the loop
> operation on a schedule or set to "Snap" to lock out cooling in the winter
> and vice versa.
>
>
>
> -          System 9 and 10 are available in 2007 as a addendum.
>
>
>
> -          In the non-cooled spaces I would check and see if there is
> still a minimum ventilation that needs to be maintained year round.
> Otherwise use the system 9 mentioned before, it is a hot water unit heater.
> It is easier and more realistic in my opinion than adding cooling where
> there is none.
>
>
>
>
>
>
>
> Brendan Hall,  PE, LEED AP BD+C
>
> Engineer, Mechanical
>
> karpinski
> ENGINEERING
> 3135 Euclid Avenue
> Cleveland, OH  44115
> P  216.391.3700 Ext 3111
> E  *bhall at karpinskieng.com <bhall at karpinskieng.com>*
> W *www.karpinskieng.com <http://www.karpinskieng.com/>*
>
>
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Bishop, Bill
> *Sent:* Friday, February 07, 2014 10:39 AM
> *To:* Nick Patsos
>
> *Cc:* equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] Water to water geothermal heat pump /
> Radiators / No cooling / Natural ventilation
>
>
>
> Nick,
>
> You could try running your model with water-to-air heat pump systems first
> (DX systems with water-cooled condensers), connected to a Water Loop HP
> loop with rejection to a Ground Loop HX of TYPE = HORIZ-SLINKY-LOOP (or
> whatever is appropriate for your closed-circuit loop, and sized per your
> actual design). A custom Hourly Report will give you the ground loop
> temperatures which you can then use to create the temperature schedule for
> the LAKE/WELL HX.
>
> There is precedent for using the Systems 9/10 from 90.1-2010 for LEED. You
> can probably find the CIRs or other reference in the list archive.
>
> ~Bill
>
>
>
> *From:* equest-users-bounces at lists.onebuilding.org [
> mailto:equest-users-bounces at lists.onebuilding.org<equest-users-bounces at lists.onebuilding.org>]
> *On Behalf Of *Nick Patsos
> *Sent:* Friday, February 07, 2014 10:23 AM
> *Cc:* equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] Water to water geothermal heat pump /
> Radiators / No cooling / Natural ventilation
>
>
>
> Bill thank you very much, I will look into it with the approach you
> describe.
>
>
>
> Regarding the temperature schedule for the GHX, is it possible to
> calculate it somehow? Sure there is limitation to the energy that the
> ground can receive from a closed circuit exchanger in comparison with the
> open loop that can receive any amount.
>
>
>
> The project is for LEED for Schools 2009 so it uses the 90.1-2007, no
> heating only systems there.
>
>
>
> Best regards
>
>
>
> Nick Patsos
>
> Mechanical Engineer
>
>
>
> On 7 February 2014 16:53, Bishop, Bill <bbishop at pathfinder-ea.com> wrote:
>
>  Nick,
>
> You can use a chiller of TYPE = HEAT-PUMP to model W2W GSHP. You attach
> it/them to a CHW loop of TYPE = PIPE2 (a two-pipe loop) that provides
> either hot or cold water but never at the same time, and configure the
> switchover using the Operation and Controls tabs of the loop. You can also
> add condensing boiler(s) to the two-pipe loop and stage them with the W2W
> chiller(s) using Equipment Controls and Load Management in the loop
> Controls tab. The GSHP connection to the ground loop is via a LAKE/WELL CW
> loop, to which you can attach a GROUND-LOOP-HX of TYPE = LAKE/WELL. You
> have to specify the temperatures of the HX in the LOOP-TEMP-SCH (they are
> not calculated hourly like they are for the other GHX types) or eQUEST will
> default to the monthly ground temperatures from the weather file.
>
> I would look into the heating-only Systems 9/10 in 90.1-2010 for spaces
> with no cooling.
>
> Regards,
>
> Bill
>
>
>
> *William Bishop, PE, BEMP, BEAP, LEED AP | Pathfinder Engineers &
> Architects LLP*
>
> *Senior Energy Engineer*
>
> [image: webCertified_logo_colorRGB72DPI.jpg]
>
>
>
> 134 South Fitzhugh Street                 Rochester, NY 14608
>
> *T: (585) 698-1956              *          F: (585) 325-6005
>
> bbishop at pathfinder-ea.com <wbishop at pathfinder-ea.com>
> www.pathfinder-ea.com
>
> [image: earth for signature]Sustainability - the forest AND the trees.
>
>
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Nick Patsos
> *Sent:* Friday, February 07, 2014 7:00 AM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] Water to water geothermal heat pump / Radiators
> / No cooling / Natural ventilation
>
>
>
> Hello all,
>
>
>
> I need your opinions on a very complex system that I have to model for
> LEED in eQuest.
>
>
>
> The system is a water to water geothermal heat pump capable of producing
> hot water for heating and in the summer season chilled water for cooling,
> not simultaneously.
>
>
>
> The hot water is to be used by low-temp radiators (no fans) in spaces or
> FCUs. In some spaces ERV ventilators provide fresh air (constant speed) /
> in some only natural ventilation is provided (significant issues there to
> be discussed in due time).
>
>
>
> There are spaces which have no heating/cooling by FCUs, only radiators
> (with ERVs or without).
>
>
>
> I have made a diagram to give a quick overview picture attached.
>
>
>
> The issues are as follows:
>
>
>
> 1) I tried modelling a Loop-to-loop heat pump system producing both hot
> and chilled water but I find significant consumption in cooling (coincident
> with heating) in the winter months which is highly unusual, thus very
> increased overall consumption in comparison with the baseline packaged VAV
> (PVAVS) system. Any alternatives ?
>
>
>
> 2) For the not cooled spaces I used baseboard heating and as system PVAVS
> cooling (due to the same as baseline cooling condition), I don't know if
> this is the correct approach. For the fan power of PVAVS do I have to use
> the same as baseline kW/cfm ? What about when the system is in heating when
> only baseboards should work (no fans) ? How 's this to be modeled ? Any
> ideas?
>
>
>
> 3) For the geothermal loop, I have a ground loop heat exchanger, now
> modelled as Lake/Well (due to limitations of the Loop to Loop heat pump)
> but in reality it will be a straight pipe closed circuit loop. I remember
> reading about creating a custom temp. schedule to model the exchanger, is
> it possible ?
>
>
>
> 4) Something more obvious than the above but still unsure, is PVAVS in
> eQuest the way to model Packaged VAV with Reheat as in 90.1 ?
>
>
>
> 5) Has anyone successfully tried the Shermad-Grimsrud method for natural
> ventilation in eQuest ?
>
>
>
> As you see, it is really messed up, mostly due to the water-to-water heat
> pump. I know that I'm asking lots of questions in different topics at once.
> Ideas in any of the topics are greatly appreciated.
>
>
>
> Nikos Patsos
>
> Mechanical Engineer
>
>
>
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