surface temperatures

asked 2018-08-19 15:12:15 -0500

day9914
425 ●1 ●9

updated 2018-08-20 09:53:46 -0500

I'm simulating a building with openstudio and I'm not including cooling systems. However, I have a problem with the surface temperatures, at night, the temperature inside and outside the building reaches up to 13 ° C and the ambient temperature is at 21 ° C. I understand that a surface that is not receiving any kind of cooling with equipment, reach a lower temperature at room temperature.

I've been with this problem for several weeks. Can anybody help me ?

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answered 2018-08-20 02:33:43 -0500

Avi
4300 ●2 ●11

I believe that the ground is cooling down your model. In E+ (and OS) if you don't enter ground temperature into the model the default values might cool down the building.

In the case of ground coupled small to medium house, it might be that the default ground model is cooling down the house. You can start by changing the Site:GroundTemperature:BuildingSurface to the year average outside air temp.

If you further read in the above link to the Input Output Reference you will find that it is better to use the Slab or Basement program to calculate ground temperatures.

I would recommend on using the foundation Kiva you can read more about that here.

Depending very much on the site weather (dry and cloud less) night sky temperatures can also result in heat loss enough to bring the zone temperature below outdoor air temperature, but only in special cases with a weak roof, and this is not likely to draw the zone ~8C below the air temperature.

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Hi, Avi. Thanks for your answer, it effectively changes the temperature of the floor and the indoor air temperature is closer to the outside air temperature. I would like to ask you something else. The element only has one floor and the roof material of the building is made of metal (zinc) and this at night is very cold with a surface temperature of 14ºC. I changed the floor temperature, but the roof temperature did not change. I do not know if this is because it is a metal with a great thermal conductivity, however, the temperature of the surface does not have to be less than the ambient temp