Re: [EnergyPlus_Support] Calculation of intermittent heating/cooling

["Michael J. Witte" <mjwitte@xxxxxxxx>]

There are multiple ways to turn off heating for a period of time:

1.  Schedule the thermostat heating setpoint to something cold, such as 0C.  
However, this is only works with thermostat control types 1 = Single Heating 
Setpoint, and 4 = Dual Setpoint with Deadband.  With control type 3 = Single 
Heating Cooling Setpoint, this is also the cooling setpoint, so the thermostat 
will request cooling to 0C!

2.  If no heating or cooling is desired (all HVAC systems are off), you can 
schedule the thermostat control type to be 0.

3.  The equipment can be scheduled off.  In the case of PURCHASED AIR, use the 
"heating availability schedule" and "cooling availability schedule" to shut off 
heating or cooling at the desired times.

Any one of the above options can be used.

Regarding the last question, if the space temperature is above the heating 
setpoint in the winter, then the combination of solar gains and internal gains 
(lights, people, equipment, etc.) are more than enough to balance losses 
through the building envelope.  Check the magnitude of these gains, check the 
building surface descriptions (are exterior surfaces set to 
OutsideFaceEnvironment = ExteriorEnvironment, has INFILTRATION been included, 
are the surface thermal properties correct).  

Mike


On 30 Oct 2005, at 7:47, wnstot wrote:

> Hi, everyone,
> I want to calculate a intermittent heating during the winter.
> According to the example of Purchair model, set the heating setpoint to 
> 0C when air conditionor is off, and 22C when it is on using the SINGLE 
> HEATING/COOLING SETPOINT thermostat controls. Therefore, the thermostat 
> will be satisfied when the room air is above 0, and heating will be 
> turned off. This really works, but it brings out another question, 
> during the daytime the room temperature will be increased to over 22C, 
> and the thermostat seems does not works. At many times during the 
> winter, heating is only needed at the first hour when the heating 
> setpoint is change from 0c to 22c, and there is no need for heating at 
> the other time (the room air is very high, about 23-30c).
> Could you give me a hand about this problem?
> Or give me an example of intermittent heating/cooling ?
> 
> Thanks.
> 
> Lei
> 
> 
> 
> 
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> 
> 
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
> 
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
> 
> Attachments are not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
> 
> EnergyPlus Documentation is searchable.  Open EPlusMainMenu.idf and press the
> "search" button.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 
> 
> 



========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx




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