Internal temperatures for different constructions

asked 2018-02-26 07:00:07 -0600

Eduardo
11 ●2

updated 2018-02-27 18:50:31 -0600

__AmirRoth__

4446 ●5 ●17 http://bleedinggreenna...

Hello there,

I'm analysing the internal temperature of two models with same characteristics (north orientation, facade colors, shadings). The only difference between them is the construction type: one model has ceramic blocks, and the other one, concrete blocks.

After simulating, i've noticed that the internal temperatures for the model with concrete blocks is lower than the model with ceramic blocks. I'm wondering why this is happening, due to the transmittance of the ceramic blocks.

I've already checked the U factor on both models, aswell as the construction types of every external and internal zone. Also, i've inserted zone infiltration on both models (1 ren/h).

Anyone has any idea of what might be the problem?

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answered 2018-02-27 14:08:02 -0600

Avi
4320 ●2 ●11

To my best understanding the results you are seeing make sense and depend on many other factors you didn't mentioned (apart of the U factor and infiltration factors like solar heat gain and internal gains are crucial). So free running model's temperature make less sense as a benchmark.

If you are after telling which construction would work beter in the sense of energy consumption then I belive you should consider using the ideal load air system which will let you compare the energy needed to maintain the models' thempratures in the comfort zone.

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answered 2018-02-28 10:17:11 -0600

Eduardo
11 ●2

I see. Thanks for the answer!

I'm trying to compare the internal temperature of these two models without any active strategy (such as HVAC), and considering zero internal loads, such as people, lighting and equipment. Basically, i'm trying to extract the hourly internal temperature of these zones. Also, both models have the same solar hear gain.

According to the Tables, the ceramic block model has the U factor of 1.1 W/m².K, while the concrete block model has 2,1. The ceramic block template should not have lower internal temperaturer, due to low transmittance?

My construction for the ceramic block model is: 10 mm ceramic wall + airgap + 10mm ceramic wall + airgap + 10mm ceramic wall + airgap + 10mm ceramic wall. The concrete block has 2,5 cm concrete wall + airgap + 2,5 cm wall.

The construction can consider that much airgap without compromising the results?

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@Eduardo please replace this with a comment under the previous answer, you may have to shorten it. If you have new information about your model, please add that as an 'update' to you original question.

David Goldwasser ( 2018-02-28 11:07:01 -0600 )edit

U gives values for certain enclosures knowing thick. If thick changes, U will change. Conductivity gives values for materials, independently of thick. You are saying you give values about ceramic and concrete blocks, but you must consider air gaps, and I dont know if your U values have account of this. Having account air gaps is not difficult to know U, and to know which solution is better. By the other hand, depending of the weather one solution may be better than the other one for a location.

cirulo ( 2018-03-01 09:03:07 -0600 )edit

I'm simulating both models in São Paulo, Brazil (average temperatures, maximum Outdoor Air Drybulb Temperature is 31,9 ºC). I'm expecting that the ceramic block model will give me a better internal temperature. Is it correct?

I'm using e+ 8.1 for these simulations. Does the version might have such influence on the results?