RE: [EnergyPlus_Support] DX Cooling Coil warning

[RRaustad@xxxxxxxxxxxx]

Have you tried using a SetpointManager:SingleZone:Cooling to control  
your cooling coil?

Quoting "James V Dirkes II, PE" <jvd2pe@xxxxxxx>:

> Dear Vinay,
>
>
>
> Standard 90.1 says you must model a heating and cooling system, but does not
> say that it must be operating continuously.  Obviously, most cooling systems
> are OFF during cold weather; this is normal and expected.  I suspect that
> cooling IS available via an economizer control.
>
>
>
> If, for some reason, you actually need to operate your DX system in the
> middle of the winter as sometimes is the case, I'm not sure what to do.  I
> think, though, that you can adjust the coil curves to reflect the actual
> equipment's operation without causing a problem in E+.
>
>
>
> The Building Performance Team
> James V. Dirkes II, P.E., LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
>
>
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Vinay Devanathan
> Sent: Thursday, July 08, 2010 8:54 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: Re: [EnergyPlus_Support] DX Cooling Coil warning
>
>
>
>
>
> Mr. Dirkes,
>
> Thanks for your reply.
>
> But, I have a question. According to Appendix G, should the system not be
> capable of providing heating and cooling throughout the year?
>
> Regards,
> Vinay
>
> On Thu, Jul 8, 2010 at 8:45 PM, James V Dirkes II, PE <jvd2pe@xxxxxxx>
> wrote:
>
>
>
> Dear Vinay,
>
>
>
> .         A simple way to fix this is to assign an availability schedule to
> the cooling coil which is ON only during warmer months.  For the coil below,
> I've used an "AlwaysOn" schedule, but you can create any schedule that you
> like, perhaps similar to the one I show at the bottom.
>
>
>
>
>
>
>
>
>
> The Building Performance Team
> James V. Dirkes II, P.E., LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
>
>
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Vinay Devanathan
> Sent: Thursday, July 08, 2010 8:24 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] DX Cooling Coil warning
>
>
>
>
>
> Hello All,
>
> How do I control a Dx:CoolingCoil from operating when the inlet air
> temperature required no cooling. In my case,
>
> Full load outlet air dry-bulb temperature < 2C. This indicates the
> possibility of coil frost/freeze. Outlet temperature = 1.90 C.
>    **   ~~~   **  ...Occurrence info = RUN PERIOD, 01/16 11:24 - 11:26
>    **   ~~~   ** ... Possible reasons for low outlet air dry-bulb
> temperatures are: This DX coil
>    **   ~~~   **    1) may have a low inlet air dry-bulb temperature. Inlet
> air temperature = 16.946 C.
>    **   ~~~   **    2) may have a low air flow rate per watt of cooling
> capacity. Check inputs.
>    **   ~~~   **    3) is used as part of a HX assisted cooling coil which
> uses a high sensible effectiveness. Check inputs.
>
> this is what happens..
>
> I have a Setpoint Manager (Mixed Air) for the cooling coil outlet node. The
> reference setpoint for this is through Setpoint manager:Singlezone:Reheat.
>
> Could anyone please tell me what is wrong with this?
>
> Thank you very much.
>
> Regards,
> Vinay
>
>
>
>
>
>



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