[esp-r] Re: Rock Store

[jake.zwart at sympatico.ca]

Hi Paul,

As a graduate of University of Waterloo, my heat transfer and solar
engineering professor was Terry Hollands.  Over the years many graduate
students did research for him and much of this ended up in a program called
WatSol, if I remember correctly.  Included in the lab was a rock storage
tank for storing solar energy.  Basically it used air as the heat transfer
fluid from the solar collectors, and stored it in the rock bed until needed.
Thus the complete solar system could utilize air as the working fluid.  

For one of my heat transfer courses I did some work on modeling the rock
bed.  Not sure if I can dig that up.

I am not sure if rock storage models made it into WatSol.  I believe WatSol
was migrated into ESP-r.  Again I don't know if this is just the solar
collection model of WatSol, or if more functionality was included.

A few years ago when I was in the design stage for our house we contemplated
a ground tube for fresh air preheat.  In the design, you always have some
misgivings, in my case what about summer time when hot humid air will come
into contact with the ground tube and result in condensation.  Initially
ignoring those misgivings I came up with a design.  Then I talked with an
expert that was familiar with ground tube research.  He stated it was never
a good idea, because there was no possible way to prevent mold growth,
particularly for a single dwelling design.  He also pointed out the rather
obvious fact that with a good HRV you are recovering the exhaust heat anyway
so a ground tube is not really giving you anything.  We killed the idea
before implementation based on this information.  So that is the cautionary
part, not knowing what you are doing.

All interesting bunny trails, but if your work needs rock storage models, it
may jog other memories or provide a lead for looking at what ESP-r may be
able to do, maybe things that are not implemented into the user interface.
Others with more familiarity will be able to help far more than I.  My guess
is that the best research for rock storage would be from the late 70's into
the early 80's.

Jake

-----Original Message-----
From: esp-r-bounces at lists.strath.ac.uk <esp-r-bounces at lists.strath.ac.uk> On
Behalf Of Achim Geissler
Sent: May-29-18 11:22 AM
To: 'esp-r' <esp-r at lists.strath.ac.uk>
Subject: [esp-r] Re: Rock Store

Hi Paul,

I would suggest taking a look at the exemplar "cellular_earth" as first
step, this features an earth-bound air pre-heating / cooling duct.
Basically, this could be expanded to a rock storage. However, you would need
to give thought in regard to adapting wall-convective heat exchange values
and also how to "add the rock mass". This could e.g. be done by adding
hanging surfaces in the "duct zones". Flow resistance could be modelled by
reducing opening area between zones, for example.

Hope this gives a starting point / some (possible, not necessarily perfect)
initial ideas.

Best
Achim

-----Ursprüngliche Nachricht-----
Von: esp-r-bounces at lists.strath.ac.uk
[mailto:esp-r-bounces at lists.strath.ac.uk] Im Auftrag von Paul
Gesendet: Montag, 28. Mai 2018 23:26
An: esp-r
Betreff: [esp-r] Rock Store

I cannot figure how to simulate a fan forced rock heat store in esp-r,where
the inlet is fan forced and the outlet is a duct. Any suggestions would be
appreciated.

Thanks,,

Paul


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