[Bldg-sim] Insulate the roof in summer without HVAC system yes or no?

[Jeremiah Crossett]

Insulation does trap heat and this is a real issue that happens in the real
world and not just in models.  There was a thread on this form last year
about it and papers posted.  I would suggest you look into phase change
materials rather then insulation- they will absorb the energy and cool the
space down to enhance comfort during the day and release that heat into the
space at night to keep it warm. There is a video of a metal building
install at this link--->
http://www.phasechange.com/index.php/en/install-portfolio/videos

In addition to PCM's I suggest you look into high emissivity / reflectivity
paints or coatings.
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*Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions*
*
120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951
www.phasechange.com
*

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On Fri, Apr 19, 2013 at 5:22 AM, David GARCIA-SANCHEZ <
dgarciasanchez at greenaffair.com> wrote:

> Hi,****
>
> ** **
>
> Thanks for your answer. Yes we have strong internal gains in this hangar
> (we suppose a high rate of lighting gain and a heavy occupant metabolism).
> But, for me is still very strange the fact that we supposed to have natural
> ventilation who it supposed to help control this strong gain. ****
>
> ** **
>
> Even if air temperature is high, the roof temperature is also higher with
> insulation that without insulation.****
>
> ** **
>
> Maybe modeling results are “correct” but one might expect that the
> temperature of wall should get reduced by using a very thin film of
> insulation. Despite the fact of the strong internal gains which are the
> same in both examples,****
>
> ** **
>
> This is a difficult case, where you wonder if the “dynamic model” is in a
> different sense of “reality”****
>
> ** **
>
> Bes regards and thanks again,****
>
> ** **
>
> David GARCIA-SANCHEZ****
>
> ** **
>
> ** **
>
> ** **
>
> *[image: cid:image001.png at 01CD52C2.E1AE1DF0]***
>
> David GARCIA-SANCHEZ****
>
> *green**affair***
>
> Tel. +33 (0)1 46 03 08 02****
>
> Mobile +33 (0)6 78 15 08 09****
>
> 102 avenue Edouard Vaillant – 92100 Boulogne-Billancourt****
>
> *www.greenaffair.com** ***
>
> ** **
>
> ** **
>
> *De :* Álvaro Lapa [mailto:ajlapa at gmail.com]
> *Envoyé :* Friday, April 19, 2013 11:46 AM
> *À :* David GARCIA-SANCHEZ
> *Objet :* Re: [Bldg-sim] Insulate the roof in summer without HVAC system
> yes or no?****
>
> ** **
>
> The increase in temperature (when isolated) could be caused by the
> internal gains. Try to confirm that.****
>
> ** **
>
> 2013/4/19 David GARCIA-SANCHEZ <dgarciasanchez at greenaffair.com>****
>
> Hi all****
>
>  ****
>
> I have a project where I need to model a maintenance hangar,****
>
>  ****
>
> In this project we are evaluating the relevance of insulate the roof to
> improve the comfort level in summer. The hangar has no air conditioned
> system but we use natural ventilation which seems to work well in our model
> (we use IES VE).****
>
>  ****
>
> The problem came when we try to put some insulating material to the actual
> roof (which is composed of only metal sheet of 2 cms). Unlike one might
> expect the temperature in the hangar increases, as the roof temperature.**
> **
>
>  ****
>
> This is to some extent logic, and I know it depends of the insulate type
> and thickness. But we agree (I think) that at least one insulation with les
> of 2cm to the actual roof should give an improvement in at least roof or
> air temperature. I know that insulation can serve as a “trap” of interior
> thermal conditions, so it’s improve HVAC systems performance. But also it
> serves to avoid the external conditions gets-in.****
>
>  ****
>
> I have tried several configurations without success, internal, external
> insulation. ****
>
>  ****
>
> And maybe some of you have already some experience in model this kind of
> configuration. We agree (I think) that I can’t recommend to my architect
> that he shouldn’t insulate its roof, but also I want to explain the
> pertinence of this with a dynamic thermal modeling.****
>
>  ****
>
> Thanks in advance for any advice on this,****
>
>  ****
>
> David Garcia****
>
>  ****
>
> ****
>
> David GARCIA-SANCHEZ****
>
> *green**affair*****
>
> Tel. +33 (0)1 46 03 08 02****
>
> Mobile +33 (0)6 78 15 08 09****
>
> 102 avenue Edouard Vaillant – 92100 Boulogne-Billancourt****
>
> *www.greenaffair.com *****
>
>  ****
>
>  ****
>
>
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