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[EnergyPlus_Support] Re: Insulating the roof



Thanks Richard and David.

David) 
Time ago I started with E+ and made some basic simulations. Then I 
started with DB because it was bougth by the institute and I hae to 
do many simulations that might take me forever if I use E+ (bless and 
curse, E+ is so clearly that it is also too much time wasting). Now 
i'm very dissapointed with DB, I'm writting a topic about now.

Ricard)
I will check the properties of the model exported to an idf. I did a 
simulation with no HVAC, the temperatures are the same.
The cities I'm simulating almost have no winter. Lets say 6 extremely 
hot months, 5 hot to moderate months and 1 cold month. The heatig 
requirements are almost null (actually zero for two of the cities). 
So, the total energy is almost the cooling energy, and it should 
change. I'm writting a topic about.

Daniel

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "David Scheer - L+U" 
<david@...> wrote:
>
> Always, always export your DB model to IDF and run from EnergyPlus 
native and check inputs and summary tables before trusting the DB 
model.  DB is a black box with too many unknowns, while E+ is as 
transparent as it can get.  Use both to take advantage of the clarity 
of E+ and the data management of DB.
> 
>   ----- Original Message ----- 
>   From: Richard Raustad 
>   To: EnergyPlus_Support@xxxxxxxxxxxxxxx 
>   Sent: Tuesday, June 24, 2008 8:14 AM
>   Subject: Re: [EnergyPlus_Support] Insulating the roof
> 
> 
>   Check the construction properties of the roof in the E+ input 
file 
>   generated by DB. Changing the roof insulation in DB should result 
in a 
>   change in the roof properties. If this does not happen you will 
not see 
>   a change in results. Also look at the cooling and heating energy 
instead 
>   of the total energy if you have not done so already. With 
increased roof 
>   insulation, cooling energy use should be reduced and heating 
energy use 
>   will increase. Although I find it hard to believe that changes in 
>   cooling and heating energy offset each other in hot dry climates, 
it is 
>   possible that the total energy did not change significantly.
> 
>   Daniel Solís wrote:
>   >
>   > Hi E+,
>   >
>   > I simulated a house with DesignBuilder in a very hot and dry 
climate.
>   > I insuated the roof with EPS polyestyrene. No matter how much
>   > insulation I used, the results were almost the same.
>   >
>   > In DB forum I got the answer that no matter the climate, the
>   > temperature and HVAC consuption is entirely driven by internal 
gain
>   > and so there is no difference insulating the roof.
>   >
>   > It's all the opposite I have read in the state of the art. 
Even, in
>   > that specific city I got the weather file from, there is a 
government
>   > support for people to insulate their roofs because they have a 
lot of
>   > measurements proving an HVAC reduction of 15-20%.
>   >
>   > Since DB uses E+ as core program, I'm asking you directly what's
>   > happening,
>   >
>   > Thanks,
>   >
>   > Daniel
>   >
>   > 
> 
>   -- 
>   Richard A. Raustad
>   Senior Research Engineer
>   Florida Solar Energy Center
>   University of Central Florida
>   1679 Clearlake Road
>   Cocoa, FL 32922-5703
>   Phone: (321) 638-1454
>   Fax: (321) 638-1439 or 1010
>   Visit our web site at: http://www.fsec.ucf.edu
> 
>   UCF - From Promise to Prominence: Celebrating 40 Years
>



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