[Equest-users] VRF Heat Recovery Calculations

[Sharad Kumar]

Hi Travis,

I can understand your problem but the achieved negative cooling load can be
due to the less cooling requirement at that time.
The cooling system is deprived of that part by the heat recovery wheel as a
result of simulation.
The negative cooling load is being seen at the cooler part of year.
Now the heat recovery can use the hot air from the zone and return it back
to the zone and making the cooling system behave like this.
This is happening in only two zones of basement.
So due to the less heating load in those spaces this thing is happening.
Just try to find out those zones in basement and may be believe that
basements could have less cooling requirement.
The negative sign is just the opposite to that nature.
So if the cooling load is negative then it is believed that there is
heating load.If any more issue then may be there is some incorrect input in
the model. like thermostat set-point, heating, cooling or fan schedules.

Thanks,
Sharad.

On Thu, Jul 30, 2015 at 3:57 AM, <equest-users-request at lists.onebuilding.org
> wrote:

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>    1. VRF Heat Recovery Calculations (Travis Miller)
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> ---------- Forwarded message ----------
> From: Travis Miller <tmiller at dcengineering.net>
> To: "equest-users at lists.onebuilding.org" <
> equest-users at lists.onebuilding.org>
> Cc:
> Date: Wed, 29 Jul 2015 22:21:35 +0000
> Subject: [Equest-users] VRF Heat Recovery Calculations
>
> I have created some heat recovery calculations for a VRF system following
> the Energy Trust of Oregon guidelines and I am getting some underwhelming
> savings.
>
>
>
> The project is a 4-story office building, one of the floors is a basement,
> and there is approximately 9000 SF per floor. 1 VRF air cooled unit per
> floor except for the third, where there are two. There might not be enough
> load diversity between zones to generate much heat recovery. One strange
> thing is that I am getting negative elec input to heat/cool numbers
> exported from the CSV hourly reports. Has anybody encountered this before?
>
>
>
> I have attached my excel file for reference (sorry for the size – not sure
> how to compress an excel file). Any feedback would be much appreciated.
> Thanks in advance for your help.
>
>
>
> *Travis Miller, PE*
>
> *DC Engineering*
>
> O: 406-829-8828; x. 209
>
> 123 W. Spruce ST.
>
> Missoula, MT 59802
>
> www.dcengineering.net
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>
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