This was brought up by Bruce a while back but the recent heat wave here has spiked my interest in the idea again.
I see there are a few different commercial systems being offered for this now, mostly industrial scale.
My original concept was to freeze a chest type unit full of water. The reason I rejected it initially was that I could not find a freezer with sufficent power to freeze it's capacity in 12-24 hours.
I have had a rethink on this as I can see that while it may not be possible to cycle a unit in perpetuity, It may provide some days off offset cooling.
Here even in summer the AC is not required every day and this would give a chance for a unit to take the time to freeze to solid and the invested energy to be used when needed. Even if it did not see through an entire hot weather event or only supplied cooling some days it would be advantageous.
So Bruce et al, I'd like to get some ideas and feed back.
First thing I am unable to find ( despite a variety of search terms in google) is how much energy in kwh is in a Litre of water when frozen or ice, whichever the correct paramater would be? I saw something that suggested that the energy storage was less than I thought, about 46.5 KW in 500L of Ice. that would be 1-2 Days cooling here.
If I can figure the accurate amount, I'll have a much better idea of cooling capacity.
Looking at some freezers, I see the small ones seem to have the same motor power as the larger ones... at least on some brands. Wondering about the tradeoff here. Would it be better to try and freeze a smaller amount of water faster or have a larger reserve that takes longer to recover? Spose that would depend on what the cycle rate may be. Ideally having multiple smaller units would effectively invest more power into a given amount of water than one larger unit.
My other concern is that ice expends when it freezes. If I fill a freezer up or to say 80%, will the expansion go up to the vacant area or will it push out the sides and push the freezer unit apart? I'm thinking up from freezing ice cubes etc but not sure that freezing and amount of water from the bottom up to a couple of feet will be the same.
Finally, How would the brains trust suggest setting up such a unit?
My thoughts are to have some coiled pipe ( NOT copper because I simply have an aversion to every Fker on YT using a copper coil as a HE!
) but something like that plastic water pipe for home use PTFE? or having a look at cutting an expansion coil out of a large AC unit my mate has a stack of with say 1/2" to 3/4 in/outlets or a car heater core or 3 which are also 3/4".
Through this I would run an antifreeze/ Brine soloution so the exchange medium did not freeze and stop the show in it's tracks. From there I'd have a circulation pump and send the chilled water through a radiator/ heater core and back to the Freezer HE.
I'm wondering if anything special would have to be done to ensure good convection and cold transfer to the HE in the freezer unit. Minds vision is the internal HE would be frozen in the ice and as the coolant is circulated the internal HE is warmed melting the surrounding ice and the water then surrounding it is chilled by the ice. Question is of this would take place quick enough with something like heater cores or a long length of Tube would be needed to give a larger melting area.
I can see the HE at some point being surrounded by many Cm of water before there is any actual ice and wondering about the transfer of water through said water.
Anything to be aware of or alternative setup suggestions?
Next idea would be how to set one of these up?