Re: [EnergyPlus_Support] Energy Plus Phase change materials

Thanks for the advise. I am seeing surface temp changes, and the model is showing savings, my concern is that changing the temp/enthalpy sets does not change the value of the savings. If there was even so much as 1 kBtu difference in any of my experiments I would be satisfied in the concept that the model can be adjusted for different thermal proprieties of PCM's. That said I will create a summery of input data and output results and send it to you.

May I ask your experience in modeling PCM's in Energy Plus?

Also the project is to show the difference of bioPCM technology compared to parifn and salt based PCM's, so showing a difference is a must.

So far I have started with example file data, then compared to product test data with no change, altered the specific heat of the material the PCM is applied to, used the product temperature for thermal conductivity, and no change in results.

My latest ideas have been to change the global finite difference algorithm settings, or variable thermal conductivity but the engineering reference and input output guide do not give much info on this possible workaround..

I am thinking of changing from this IDF,HeatBalanceSettings:ConductionFiniteDifference,FullyImplicitFirstOrder,3.0,1.0,0.002;

IDF,HeatBalanceSettings:ConductionFiniteDifference,CrankNicholsonSecondOrder, 1, 1, .01;

As to widen the thermal spectrum, but am very unsure if this makes any sense..

Here is the best data I have

IDF,MaterialProperty:PhaseChange,DrpceilPCM ,0.2,-20,0.1,22,18260,22.1,32000,27,36174,27.5,62941,28,107338,28.5,157508,29.01,180796,29.51,194698,30,201585,31,202659,32,202521,35,202570,40,204475,44.64,208301,60,210000;

I will keep experimenting, summarise and send you the summery..

Thanks for your time

On Sat, Jan 21, 2012 at 8:40 AM, Edwin Lee <leeed2001@xxxxxxxxx> wrote:

Jeremiah:

I don't have enough time right now to go through all your files, but thought I'd make a recommendation. Can you plot or otherwise mine the construction (surface and finite difference nodal) temperatures to make sure that the wall temperature actually makes it into the phase change region of your data? I'll try to keep thinking but I am quite sure the phase change simulation works well (under the model assumptions), and once you have the input data in the right form. I'll try to look at your data as well, but can't right now, sorry.

Good luck,
Edwin

On Fri, Jan 20, 2012 at 17:58, CleanTech Analytics <jeremiah@xxxxxxxxxxxxxxxxxxxxxx> wrote:

I am working on modeling phase change meterials in Energy Plus to model phase change materials, Here is an example what I am working on creating output visualization (once I get the modeling figured out) https://docs.google.com/spreadsheet/ccc?key=0Angnu5sp0FF9dFB6RlNYSkZyMW5MUTd0cmNxZGhpbnc

I ran an experiment with the generic data from the example phase change materials IDF, as well as four varieties of data configuration and bench marked them against an identical building with no phase change materials and was very disturbed at the results.

All buildings with phase change use exactly the same amount of energy!
It makes me wonder if the phase change calculations are not really using the input data, as the energy is the same kBtu for each.. Below is the graph and here are links to my analysis sheets..

Output Data in question https://docs.google.com/spreadsheet/ccc?key=0Ak5Rfmjyon9idHpKQnI5ZVp5T0UxeThNTTVIcUg0aGc

The results piloted below

Any help or advise would be great, as I want to compare phase change products, brands and technologies but if the enthalpy temperature data does not change the outcome then that seems impossible.

--
Jeremiah D. Crossett

CleanTech Analytics

503-688-8951
www.cleantechanalytics.com

This document may contain valuable information proprietary to CleanTech Analytics which is private and confidential. It may not be shared, copied, stored or transmitted in any form without the prior written consent of CleanTech Analytics

--
Jeremiah D. Crossett

CleanTech Analytics

503-688-8951
www.cleantechanalytics.com

This document may contain valuable information proprietary to CleanTech Analytics which is private and confidential. It may not be shared, copied, stored or transmitted in any form without the prior written consent of CleanTech Analytics

Jeremiah D. Crossett

CleanTech Analytics

503-688-8951

www.cleantechanalytics.com

This document may contain valuable information proprietary to CleanTech Analytics which is private and confidential. It may not be shared, copied, stored or transmitted in any form without the prior written consent of CleanTech Analytics

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