[Equest-users] Free cooling Chiller on eQuest

[Sebastian Carrizo]

Neil,

Thanks for the very insightful response. The system I'm trying to model is
a packaged air cooled/free cooling chiller. I will have to dig deeper into
the specs to see if it works partially or just as eQuest models it.
When setting the parameters for my CT how should I set the range and
approach so that when ambient temp hits -5C then free cooling takes over?

Regards

Sebastian


On Thu, Feb 6, 2014 at 1:07 AM, Neil Bulger <nbulger at integralgroup.com>wrote:

> The water side economizer chiller should be thought of as a
> secondary-cooling device on a CHW loop and will cause many head aches if
> used by itself without any actual chiller object.  On a CHW loop, actual
> chillers are the only elements that can be used to autosize a CHW loop and
> any attached CW loop. Without one, loops will not size and the model will
> crash.
>
> The error you posted is only a partial story so it is hard to know the
> full problem. My guess is you have the WSE chiller on a dedicated cooling
> tower loop, possibly called DEFAULT-CW, and there is no other chiller
> attached to this CW loop. In this case, the CW loop will not size itself
> upon simulation because eQuest does not see the WSE as a primary source of
> cooling. *You can manually size the loop, any pump, and the cooling tower
> and the model should run.*
>
> In a larger picture of accounting for WSE, eQuest can only really capture
> a non-integrated water side economizing (WSE). This setup and control
> scheme means that the WSE heat exchanger will only operate if the cooling
> tower and HX are able to handle the full cooling load. In several
> scenarios, this is a very rare occurrence given standard CHW supply
> temperatures and the low wetbulb temperature required to make this for free.
>
> It is possible to design a system where a WSE heat exchanger only handles
> part of the load and pre-cools the return water before it goes to the
> chillers which handles the remainder. However, it is impossible to model
> such a system in eQuest. EnergyPlus and IES are the best bet for something
> like this and even then, it can be tricky to capture the full benefit. It
> would likely be easiest to post process the eQuest hourly outputs of the
> cooling load if you have a true fully integrated WSE.
>
> Happy eQuesting!
>
> *Neil Bulger, PE* | Energy Modeling Team Manager
>
> *Integral Group *| 427 13th Street | Oakland CA USA 94612
> T 510.663.2070 x235
> c 707.363.3954
>
> integralgroup.com <http://www.integralgroup.com/> |
> nbulger at integralgroup.com
>
>  *Trust* | *Nurture* | *Inspire*
>
> Please consider the environment before printing this email.
>
>
>
> On Wed, Feb 5, 2014 at 1:34 PM, Sebastian Carrizo <
> juan.carrizo at alumni.carleton.ca> wrote:
>
>> Thanks for the quick responses. After setting the parameters to match my
>> design conditions I keep getting the error
>>
>> *Tower: Dummy CT on loop DEFAULT-CW is not needed.  No simulation will be
>> performed.   *
>>
>> Any thoughts?
>>
>>
>> On Wed, Feb 5, 2014 at 3:52 PM, Paul Riemer <Paul.Riemer at dunhameng.com>wrote:
>>
>>> Some of these have an economizer functionality that can operate instead
>>> of or in series with the compressors.  I was excited about this once but
>>> the first pass showed it wouldn't payoff for my project.  If your situation
>>> shows promise, you need a detailed model, and if an eQUEST waterside
>>> economizer will not give you the series functionality, then I wonder if you
>>> could model the modes as separate air cooled chillers in eQUEST with custom
>>> curves for each and staging based on outdoor air or seasonal dates.  Good
>>> luck.
>>>
>>> *Paul Riemer, PE, LEED AP BD+C*
>>>
>>> *DUNHAM*
>>>
>>>
>>>
>>> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
>>> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Bishop, Bill
>>> *Sent:* Wednesday, February 05, 2014 2:33 PM
>>> *To:* Sebastian Carrizo; equest-users at lists.onebuilding.org
>>> *Subject:* Re: [Equest-users] Free cooling Chiller on eQuest
>>>
>>>
>>>
>>> Sebastian,
>>>
>>> It sounds like you're talking about a water-side economizer, which can
>>> be modeled as a WATER-ECONOMIZER, one of the chiller types in eQUEST.
>>>
>>> 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 <%28585%29%20698-1956>              *          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 *Sebastian
>>> Carrizo
>>> *Sent:* Wednesday, February 05, 2014 3:15 PM
>>> *To:* equest-users at lists.onebuilding.org
>>> *Subject:* [Equest-users] Free cooling Chiller on eQuest
>>>
>>>
>>>
>>> Hi all,
>>>
>>>
>>>
>>> I'm trying to model a packaged air cooled/free cooling chiller in
>>> eQuest. I was hoping someone could shed some light as to how one would go
>>> about doing this.
>>>
>>>
>>>
>>> Regards,
>>>
>>> Sebastian
>>>
>>>
>>>
>>> --
>>>
>>> *Juan Sebastian Carrizo*
>>>
>>> M.Eng Sustainable Energy | B.Eng Industrial Engineering
>>>
>>> (c) 647-225-2243 | juan.carrizo at alumni.carleton.ca
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>> --
>>
>> *Juan Sebastian Carrizo*
>> M.Eng Sustainable Energy | B.Eng Industrial Engineering
>>
>> (c) 647-225-2243 | juan.carrizo at alumni.carleton.ca
>>
>>
>>
>>
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>


-- 

*Juan Sebastian Carrizo*
M.Eng Sustainable Energy | B.Eng Industrial Engineering

(c) 647-225-2243 | juan.carrizo at alumni.carleton.ca
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