[Equest-users] Daikin heat pump curves

Tue Jun 2 05:58:03 PDT 2015

Dear Sambhav,

I have done some analysis over these curves.
What i found is that only bi-quadratic dependent on T can be imported in
the following place.

[image: Inline image 2]

Also a sample bi-quadratic -T has been pasted below

[image: Inline image 3]

Now the resulting Z is EIR depending upon X (External wet bulb temperature)
and Y (Outside dry bulb temperature) which can be observed in the first
figure, where bi-quadratic dependent on T can be imported.

..................................................................................................................
Also the wet bulb and dry bulb temperature are of air and not of any liquid
(refrigerant or water).

Hence this curve is totally dependent upon the external air and temperature
conditions .Hence as per me the curve can be used for any heat pump.

.......................................................................................................................
Now the part load based EIR curve is bi-quadratic dependent on part load
value. A sample curve is given below.

[image: Inline image 4]

This is bi-quadratic but not dependent upon T else on IPLV or part load
ratio.
Also EIR based on IPLV is calculated by bi-quadratic equations with four
curve coefficients and one variable as part load ratio (IPLV with
efficiencies at various loading percentages). You can surf it on internet.

Hope this can help.

Thanks,
Sharad .Kumar
Green Horizon Consulting LLP
Gurgaon
India.
https://www.linkedin.com/profile/view?id=151208255&trk=nav_responsive_tab_profile

On Tue, Jun 2, 2015 at 1:32 AM, <equest-users-request at lists.onebuilding.org>
wrote:

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>    1. Re: Daikin heat pump curves (Sambhav Tiwari)
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>
> ---------- Forwarded message ----------
> From: Sambhav Tiwari <tiwari.sambhav at gmail.com>
> To: Julien Marrec <julien.marrec at gmail.com>
> Cc: equest-users <equest-users at lists.onebuilding.org>
> Date: Mon, 1 Jun 2015 03:31:49 -0700
> Subject: Re: [Equest-users] Daikin heat pump curves
> These curves are same for all HP units how is it possible
>
> Regards
> Sambhav
>
> On Thu, Jul 17, 2014 at 4:45 AM, Julien Marrec <julien.marrec at gmail.com>
> wrote:
>
>> Hi,
>>
>> I've been trying to model a Daikin VRV system and trying to figure out
>> why I was getting 100 times more space heating in the proposed (VRV) model
>> compared to the baseline model (PTHP). After isolating the problem to the
>> VRV, I found a conversation from March 2014 between a few folks (Byron
>> Burns and Bill Bishop mostly - thank you both!), that basically explained
>> why I was getting the issue: the .inp data from Daikin isn't importing
>> correctly.
>>
>> I just wanted to say that we're in July now, and this still hasn't been
>> fixed (I downloaded the curve from Daikin a few days ago), so if you're
>> having the problem, the fix proposed by Byron and Bill still works. It
>> consists in to replacing the VRV Heating Curve with:
>>
>> "VRV Heating EIR-F-EWB/ODB AC" = CURVE-FIT
>>    TYPE             = BI-QUADRATIC-T
>>    INPUT-TYPE       = COEFFICIENTS
>>    COEFFICIENTS     = ( -1.85025, 0.0620141, -0.000312822, 0.07145853,
>>          -0.0003626328, -0.0007776424 )
>>    ..
>>
>> (at least that's how I understood it and it seems to be working).
>>
>> I've attached the performance curves with repaired Heating EIR for VRV.
>>
>> I'll email Daikin to let them know (again), maybe others will want to do
>> the same so that they realize this is a problem encountered by more than
>> one individual
>>
>>
>> Have a great day,
>> Julien
>> --
>> Julien Marrec, EBCP, BPI MFBA
>> Energy&Sustainability Engineer
>> T: +33 6 95 14 42 13
>>
>> LinkedIn (en) : www.linkedin.com/in/julienmarrec
>>
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