Second system extension extension.

[Joeboy]

Well, with no salt to hand I filled a few lidded boxes to a total of 7 ltrs and stuck em in the freezer alongside the 3 types of gin, ice cubes and frozen glasses. Max we see out here is about 4 hours without power, at a push 6. I have a 200ltr water tank on ballcock in the highest part of house that kicks in, multiple usb battery packs and this added coolbox scenario. Keeps it all civilised in the GnT dept along with water for toilets and enough head pressure to run the lower level shower. Beyond that we go to scented candles and the fridge for ice cubes....
I reckon we are good for about 2.5 days.

Are you guys seeing the freezer box photo? Please confirm one way or t'other, thanks.

Not much food to perish in the every of an outage in there!

Holiday freezer Bro, eating's cheating. Want to see the steak fridge?


Freezer here is set to minus 14, will see if we are solid blocks tomorrow. As an aside SWMBO & I have been looking for a second hand chest freezer for the cabin back home. Somewhere to store the end of season bounty. Might do with a couple of solar set ice blocks in it?
P.S, not involved in the brine part of this conversation yet but enjoying reading about it.

[openspaceman]

I can't get my head around the point of the brine yet, I see that it stays fluid at a much lower temperature, which might offset the lower SH, also that water-ice has a poor SH and thermal conductivity which count against it too.
I know that NaOH gives out a lot of heat when you dissolve it, also that CaCl gets cold, but I can't find any way that the salt in brine will mop up a lot of heat in a phase-change. https://en.wikipedia.org/wiki/Enthalpy_ ... f_solution shows that salt has a pretty trivial Enthalpy change on solution compared with big +ve and -ve numbers for other compounds. I don't think that latent heat of fusion is relevant here, although I was surprised to see that you can use latent heat of fusion to predict solubility.

Specific heat is irrelevant in what we are trying to do with a liquid with a melting point at the temperature we wish to keep stable because the temperature hardly changes and specific heat only stores the energy per unit mass per degree change in temperature.

What we are looking to do is store heat as the phase of the brine changes from solid ice to liquid brine.

To change 1kg of ice to liquid requires 334kJ or 0.09kWh, so the temperature of the freezer will stay fairly constant as the ice melts as long as the ice can absorb the all heat in the same way an iced drink stays cold until all the ice has melted

I wondered whether it would be worth using water-ice but with heat conductors threaded through: like several upside-down top-hats of copper bar in the water tray so that the low conductivity of ice doesn't handicap it so much...
A

yes or layers of shallow aluminium trays

[Joeboy]

Well, with no salt to hand I filled a few lidded boxes to a total of 7 ltrs and stuck em in the freezer alongside the 3 types of gin, ice cubes and frozen glasses. Max we see out here is about 4 hours without power, at a push 6. I have a 200ltr water tank on ballcock in the highest part of house that kicks in, multiple usb battery packs and this added coolbox scenario. Keeps it all civilised in the GnT dept along with water for toilets and enough head pressure to run the lower level shower. Beyond that we go to scented candles and the fridge for ice cubes....
I reckon we are good for about 2.5 days.

Are you guys seeing the freezer box photo? Please confirm one way or t'other, thanks.

Not much food to perish in the every of an outage in there!

Holiday freezer Bro, eating's cheating. Want to see the steak fridge?


Freezer here is set to minus 14, will see if we are solid blocks tomorrow. As an aside SWMBO & I have been looking for a second hand chest freezer for the cabin back home. Somewhere to store the end of season bounty. Might do with a couple of solar set ice blocks in it?
P.S, not involved in the brine part of this conversation yet but enjoying reading about it.

Our large ice cubes (3ltr,2ltr,2ltr) were solid the next morning so we are go for a Turkish powercut(which of course wont happen now)! The other benefit we have in the freezing process is that the room a/c is whipping away the fridge freezer radiated heat quickly so the ice forms swiftly. I think I'll do solar powered ice block formation in the chest freezer once I get it. Another way to store and use that solar excess when it is present?

[Joeboy]

First day in many, many months where we didn't max out the stack charge. Ran the stack all the way down to 28% charging the HWT first thing this morning. End of the day we hit 84% SOC, looking forward to the moving up of the groundmount triple next week to max out potential.

[Joeboy]

Day 2 in the rain sequence at home according to the forecasts. Our son uses the house while we are away and like his Mum and Sister likes a good 3 week long shower! This is handy for me as it let's me dump the battery power into the HWT again this morning and see how much we charge from PV in marginal conditions. A great test of the larger array in the sort of scenario it was built for.
Down to 17% soc and pulling 3.240kW from the stack at 08.24 uk time. Will keep going until the inverter starts to draw more than 100W from grid, 22W at the moment..

Gotta love the control that the tech gives.

Edit- 08.35 uk time 12% soc and pulling 3.35kW from batteries and only 22W from grid.
Shut the HWT charging off and we'll see how it goes, left a tiny bit in the battery stack for background load. Only 43W coming in from the Solaredge, must be dark grey skies back there today!

[marshman]

__

[Joeboy]

Please, please send some rain down here, rainfall is only 99mm so far this year - 7 1/2 months !!, last decent "wet" rain was way back in February. Even the Elder and Gorse bushes are starting to wilt. Still no hose pipe ban though !

Oh dear, sorry to read that. Incredible how it can vary so much over a relatively small island. We are rain thru until next Monday at least. I hope it clears then as I have string to move! Fingers crossed for ye, I'll do a raindance!

We have seen a 5% lift in the soc at stack (now 17%).across 2.5 hrs. Background load is about 200W give or take so I'll round that to 0.5kW in 2.5hrs plus the 5%(0.72kWh) makes a total power in/use of 1.22kWh, not bad when the solaredge only accounts for 0.7kWh of that. Good to see the Victron system doing its bit. These are incredibly small figures to be bandying about especially after the great Summer yet these are the ones that interest me most. Its down here we play to keep.the grid at bay.

[nowty]

Please, please send some rain down here, rainfall is only 99mm so far this year - 7 1/2 months !!, last decent "wet" rain was way back in February. Even the Elder and Gorse bushes are starting to wilt. Still no hose pipe ban though !

So unless you get another 151mm in the remaining 4.5 months of the year, the urban myth becomes true and you really are living in a desert.

I know its no joke though.

[Oldgreybeard]

Our water butt has been practically empty for weeks now, the only water in it is coming from the aircon drain. It's trying to rain at the moment, but it's barely enough to dampen down the dust. The forecast thunderstorms haven't arrived - they were supposed to be here around breakfast time.

[marshman]

__