Re: [EnergyPlus_Support] Sizing warning message on temperature difference

You are using a vav with reheat, right. In clg mode it will reheat to the zone htg setpoint not the zone clg setpoint.

Sent from my iPhone (excuse the brevity)

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On 12.06.2013, at 03:37, Patrick Bivona <patrick.bivona@xxxxxxxxx> wrote:

Hi,

I'm getting this warning message after a run:

** Warning ** SizeZoneEquipment: Supply air temperature (calculated) within 5C of zone setpoint temperature

** ~~~ ** ...check zone thermostat set point and design supply air temperatures
** ~~~ ** ...zone = "ZONE 1F ENTRANCE WEST" first occurrence during cooling load calculations

** ~~~ ** ...predicted zone cooling load = -863.19 W
** ~~~ ** ...zone temperature = 20.00 C

** ~~~ ** ...supply air temperature = 16.00 C
** ~~~ ** ...temperature difference = -4.00000 C

** ~~~ ** ...calculated mass flow rate = 0.21163 kg/s

I understand the general purpose of the temperature difference check: avoid high flow rates.

What I don't understand is why the "zone temperature" is reported as being 20 degC, when my thermostat cooling setpoint is 24 degC.

Am I wrong in assuming that "zone temp" should be the cooling setpoint? If so, why recommend to check the zone thermostat in the warning message?

I'm confused!

Thanks in advanced for your help,
Patrick Bivona

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