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Modelling phase change domestic hot water storage tanks

asked 2014-12-04 07:05:32 -0500

updated 2015-08-03 20:01:05 -0500

I'm looking for a simple approach rather than the BCVTB and Matlab approach used in this paper presented at eSim 2014, since it needs to be built into a larger piece of software without adding any new dependencies.

The idea I had was to model a second tank which is only available to be charged once the first tank is at the melting point of the PCM and so acts like it's storing the latent heat of the phase change. Is this an approach anyone has tried? Am I missing any obvious flaws here? Or is there a better approach you can suggest?

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answered 2014-12-05 13:31:37 -0500

The two tank approach may work, but you may have difficulty controlling that. Another option to consider is making a custom fluid using FluidProperties:* that has a specific heat profile similar to the phase change material. I'm envisioning a separate plant loop for the phase change tank with a heat exchanger to the regular loop, but again, you may have difficulty controlling all the parts. Another options is to use a normal tank with equivalent storage capacity and operate it within a narrow temperature range. Ultimately, you have to question what different the phase change material will make in the overall energy use, or whether it's just a way to pack more storage into a smaller volume.

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The FluidProperties custom fluid looks like it may be what I was looking for.

Jamie Bull gravatar image Jamie Bull  ( 2014-12-06 07:33:34 -0500 )edit

Thanks for your answer, it's helped me with thinking about what's required. To clarify, our interest is in power requirements across the year more than total energy, so storage is an important factor. The availability of PCM storage with particular properties could make a big difference to how much load can be shifted at various times of year when used with an ASHP for example. I think the normal storage tank operating only above a cut-in temperature is the way to go but I'm having difficulty picturing how to lay it out and control it (as you suggested might be the case).

Jamie Bull gravatar image Jamie Bull  ( 2014-12-18 08:10:36 -0500 )edit

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Asked: 2014-12-04 07:05:32 -0500

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Last updated: Dec 05 '14