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Re: [TRNSYS-users] TRNBuild Internal Gains



João,
Make sure that the gains are specified in kJ/h and that there is not any kind of multiplication or addition factor on them if you are entering them as inputs (instead of as constant or scheduled values).

There are a few more things to check as well. First, make sure that you have a reasonable value of the thermal capacitance of the zone. By default, TRNBuild sets the capacitance to the thermal capacitance of the air in the zone. In reality, the capacitance ought to be about 5 times the default value. This will cause your zone to heat up and cool down more slowly. Second, make sure that you have not neglected infiltration in your model; outside air always enters a building no matter how well it is sealed. The infiltration rate should probably be somewhere between 0.3 and 0.7 airchanges per hour. In residences, the infiltration rate can be quite a lot higher.

As a check, you can pretty easily compute what the temperature gain of the volume of air in your zone would be since you know what the total equipment and lighting gains are and you know the volume of air.
Kind regards,
 David



On 3/12/2014 12:11, em09008 wrote:
Good afternoon,

I'm having a problem defining the internal gains of a residential house, because as soon as I add them the temperature in each zone increases about 10ºC, which is in my opinion too much...

I believe I have not used exaggerated schedules or equipment power, so I really don't know what could be wrong.

Does anyone know what could possibly be the problem here?

Thank you very much for all your attention.

Best regards,

João Mata
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