RE: [EnergyPlus_Support] VAV AHU with Reheat Control

For emergency night cooling, you can use a air to air system. In this case, the cooling can be turn on based on the zone thermostat, which can be set different from the day temperature.

For a server room, a window unit would come on, when the main system is off, and the room temperature is too high.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: wanghaojie630@xxxxxxxxx
Date: Wed, 31 Oct 2012 13:53:33 -0400
Subject: Re: [EnergyPlus_Support] VAV AHU with Reheat Control

Thanks for your reply. I actually want to combine mechanical system with night cooling strategy. And I only want the chiller be turned on when zone temperature is larger than a certain value (26 C). And if I only set the thermostat at this temperature, I see the chiller electricity consumption is even larger than when I use mechanical system along.

HJ

On 10/31/2012 1:12 PM, YuanLu Li wrote:

Why do you want to control the chiller water temperture, from the zone thermostat?

You can use a small chiller and/or large chiller to save energy, when the demand changes.

When there is no cooling demand, the chiller is cycled on and off by itself to maintain the water temperature you have specified. (7°C to 12.5°C in plant sizing). You can this temperature.

The master zone theremostat configuration controls the complressor of the air to air AHU system with DX cooling coil.

If you use the zone theremostat to turn off the chlller and let the water temperature to rise to the ODT, there may be a long delay to cool the water down again.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: wanghaojie630@xxxxxxxxx
Date: Wed, 31 Oct 2012 12:14:41 -0400
Subject: [EnergyPlus_Support] VAV AHU with Reheat Control

Hi all,

I wonder if there is a way to control the chiller based on the zone air
temperature when I use VAV AHU with reheat system. People told me that
the the thermostat will only control the damper. The chiller is
controlled by the setpoint manager for deck temperature. If I only want
to control the chiller by zone air temperature, how can I config this
system? Or I can only do this with CAV?

Thanks,

HJ

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