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Temperature inside the zone isn`t the same as the thermostat setpoint

asked 2015-03-14 23:21:52 -0600

s_pourm's avatar

updated 2015-07-11 20:10:30 -0600

Hi Everyone

I am going to model a simple zone with 2 spaces (one inside wall) in OpenStudio. I am going to find the inside wall surface temperature after a jump in temperature from 0 to 20 DegC. ( for a validation with a heat transfer problem). To do so, I model the temperature step change in thermostat set-point profile. ( from 0Am to 8AM = 0 Degc and after that 20 DegC). But when I look at the results, the minimum zone air temperature is around 12 Degc. why it does not come to zero? ( I do not know its related or not, but what is temperature type limit name? for example temperature 38)

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What is the outdoor temperature?

Dinosaver's avatar Dinosaver  ( 2015-03-15 12:04:56 -0600 )edit

It reads the weather data. regardless of outdoor temperature, I have assigned the thermostat set point to have a 0 DegC indoor temperature.

s_pourm's avatar s_pourm  ( 2015-03-15 12:23:08 -0600 )edit

And applied Ideal Loads systems?

Dinosaver's avatar Dinosaver  ( 2015-03-15 12:44:51 -0600 )edit

Yes I just applied Ideal loads systems

s_pourm's avatar s_pourm  ( 2015-03-15 13:02:49 -0600 )edit

Is it possible you have only set a heating setpoint set for 0C, and it isn't cold enough outside to get the space any colder that 12C.

Also, just for reference, if you model two adjacent spaces as one zone, the interior surface, will become an internal mass object in EnergyPlus. Not sure if that information is important for what you are doing.

David Goldwasser's avatar David Goldwasser  ( 2015-03-16 00:25:42 -0600 )edit

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answered 2015-03-17 09:01:14 -0600

s_pourm's avatar

When you choose the Ideal Loads systems, the minimum Air supply temperature is set to 13C (by default). So I changed this amount(in Idf Editor not OS) by -10 and I got my results.

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Asked: 2015-03-14 23:21:52 -0600

Seen: 458 times

Last updated: Mar 17 '15