[Bldg-sim] EE4: Boiler/Cooling Tower Set Points, and Max Heating COP

RobertWichert robert at wichert.org
Fri Apr 13 07:31:26 PDT 2012


Yes, Hayssam, I have been told the same thing, that the boiler and the 
cooling tower are in the same loop in DOE 2.1.  I don't know enough of 
the code, but whoever wrote it had never heard of hot water reheat with 
a water cooled condenser!

It seems like for that part of DOE 2.1, they only considered water 
source heat pumps and ignored VAV reheat systems.  Or maybe they figured 
that all systems with hot water reheat would be air cooled condensers, 
but that isn't true.


Robert Wichert P.Eng. LEED AP BD&C
+1 916 966 9060
FAX +1 916 966 9068







===============================================


On 4/12/2012 1:22 PM, Hayssam Barhoun wrote:
> Hi Robert,
> What I heard is the DOE2.1 gets unstable and will crash if you have a high temperature setpoint. EnergyPro and EE4 are both DOE2.1 based. That why this limitation exists.
> Also, I believe that the boiler and the cooling tower (in EE4) are on the same loop, and your boiler set point should be set lower than the cooling tower's.
>
> Hayssam Barhoun PEng, LEED AP, PhD, BEMP
> Senior Engineer | Mechanical
> Arup
> 2 Bloor Street East, Suite 2400  Toronto  Ontario  M4W 1A8 Canada
> t +1 416 515 0915 x24427  d +1 647 260 3427 
> www.arup.com
>
>
>
>
> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of RobertWichert
> Sent: Thursday, April 12, 2012 12:57 PM
> To: bldg-sim at lists.onebuilding.org
> Subject: Re: [Bldg-sim] EE4: Boiler/Cooling Tower Set Points, and Max Heating COP
>
> Justin,
>
> Do you have any ideas on how to get around having the cooling tower
> setpoint above the boiler setpoint?  This makes no sense to me with a
> cooling tower cooled condenser  and a boiler heated reheat loop.  They
> aren't even connected!
>
> I agree that the limitation is proper for a heat pump, since you don't
> want the boiler just rejecting heat to the cooling tower, but if the two
> loops are not connected (like a hydronic heating system with a water
> cooled condenser DX system) the limitation doesn't make sense.
>
>
> Robert Wichert P.Eng. LEED AP BD&C
> +1 916 966 9060
> FAX +1 916 966 9068
>
>
> ===============================================
>
>
> On 4/12/2012 12:32 PM, Krauel, Danielle wrote:
>> Justin,
>>
>> You can modify the HEATING-EIR (reciprocal of COP) in the DOE code for all zones to achieve the high COP's of a hybrid heat pump (so that you aren't using electricity (compressors) energy for heating).
>>
>> Kind regards,
>> Danielle Krauel P.Eng., LEED AP
>> Halsall Associates
>> Tel: 613.907.7540 . Toll Free: 1.877.442.5725 x 286 . www.halsall.com
>> Vancouver . Calgary . Sudbury  . Burlington . Toronto . Ottawa . Dubai
>> Best Workplaces in Canada, Five Consecutive Years: 2007 - 2011
>> __________________________
>> A Parsons Brinckerhoff Company
>>
>>
>> -----Original Message-----
>> From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of bfountain at greensim.com
>> Sent: April 12, 2012 3:22 PM
>> To: Justin Elkin; bldg-sim-bounces at lists.onebuilding.org; bldg-sim at lists.onebuilding.org
>> Subject: Re: [Bldg-sim] EE4: Boiler/Cooling Tower Set Points, and Max Heating COP
>>
>> 2) Yup - 8 is as high as you can go.
>>
>> 1) The boiler setpoint (for a heat pump condenser loop) must be lower than the cooling tower setpoint which is set on the cooling tower tab.
>> Brian Fountain
>> bfountain at greensim.com
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