[Equest-users] Question about VRF Condensing Unit Inputs

[Chris Hadlock]

thank you for your response Bhartendu, much appreciated.

Chris

On Wed, Sep 8, 2021 at 12:35 PM Bhartendu Awasthi <
bhartendu.awasthi90 at gmail.com> wrote:

> Chris,
>
> To answer your questions, I am starting with DOE definitions for these
> inputs:
>
>    1.
>
>    Number systems (multiplier): number of separate VRF systems that are
>    represented by the condensing unit. This is effectively a multiplier on the
>    outdoor unit that represents multiple identical VRF systems. All systems
>    are assumed to be equally sized.
>    2.
>
>    Max cap/system: maximum rated cooling capacity of one VRF system
>    represented by the condensing unit.
>    3.
>
>    Number outdoor units: number of outdoor units that are networked
>    together to serve a set of indoor units. All units are assumed to be
>    equally sized.
>    4.
>
>    Cooling capacity: total rated cooling capacity of the condensing unit.
>    If Number outdoor units or Number systems (multiplier) is greater than 1,
>    then the Cooling capacity is the total of all VRF systems defined for the
>    condensing unit.
>
> Cooling capacity = [capacity of one unit] * Number outdoor units * Number
> systems (multiplier)
>
>
> Now, as per my understanding of these definitions, number systems
> (multiplier) and max cap/system represent the inputs for VRF units (PVVT
> and/or DOAS) modelled separately whereas number of outdoor units and
> cooling capacity are condensing unit’s inputs. Based on this, number
> systems (multiplier) will exceed 1 when we are modelling a condensing unit
> which is serving multiple VRF units (PVVT and/or DOAS).
>
>
> So in your case, inputs will be:
>
>    1.
>
>    Number outdoor units: 2
>    2.
>
>    Cooling capacity: 24 Tons (12*2)
>
> Not sure how you have modeled the VRF units, so no comments on the other
> two inputs. I hope it helps.
>
>
> Let us wait and see how fellow eQuesters interpret this.
>
>
> Warm Regards,
>
> *Bhartendu Awasthi*
>
> -------------------------------------------------
>
> LEED AP BD+C, WELL AP, IGBC AP, GRIHA CP
>
> GEM CP, ECBC Design Consultant – PEDA
>
> Energy & Sustainability Consultant
>
> Pithoragarh, Uttarakhand, India
>
> *M*: +91 97846 53604 | *S*: bhartendu_awasthi
>
> *L*: bhartenduawasthi <https://www.linkedin.com/in/bhartenduawasthi> | *T*:
> iam_bhartendu <https://twitter.com/iam_bhartendu>
>
> On Wed, Sep 8, 2021 at 7:57 PM Chris Hadlock via Equest-users <
> equest-users at lists.onebuilding.org> wrote:
>
>> Good afternoon,
>>
>> I'm looking to better understand the Condensing Unit inputs in eQuest
>> 3.65 (build 7175) using DOE 2.3.
>>
>> My project has two (2) 12 Ton condensing units (same capacity) serving
>> approximately 40 zones.
>>
>> I'm trying to better understand the following inputs (and how they
>> relate): "Num system (multiplier)", "Max cap/system", and "Cooling
>> Capacity".
>>
>> Per the screen capture below, is the Max cap/system input the maximum
>> cooling capacity of each condensing unit? So in my case this would be 12
>> Tons?
>>
>> How (if at all) does this relate to the cooling capacity and heating
>> capacity specified under Cooling Performance and Heating Performance
>> (circled in the image below)...is that again the capacity per condensing
>> unit? If so, is this a redundant input to the Max cap/system input
>> specified above?
>>
>> Additionally, can someone provide an example of when the "Num systems
>> (multiplier)" input would exceed 1?
>>
>>
>> [image: image.png]
>>
>>
>> Thanks in advance for any help.
>>
>> ---
>> *Chris Hadlock*
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