Just an idea, haven’t looked at anything regards cost.

Large freezer to make a big block of ice. Probably underneath the house if built from new, maybe in a large insulated shed. Anyway, big freezer just to make a huge block of ice. Powered overnight from off-peak mains to freeze the block, and then topped up during the day from roof solar panels.

A network of pipes goes through the block of ice, through which air is blown and then the now cool air exhausts into the house at floor level. Hot air from the house is exhausted through the roof.

Would this work as a form of aircon? Assume the house is properly insulated and stuff.

Sure. But efficient?

Compared to a normal heat pump, I’d guess not so efficient.

Michael V said:

Sure. But efficient?

Compared to a normal heat pump, I’d guess not so efficient.

I’d agree with that. Vague memories of studying the Carnot cyle.

Carnot cycle.

D’oh!

party_pants said:

Just an idea, haven’t looked at anything regards cost.

Large freezer to make a big block of ice. Probably underneath the house if built from new, maybe in a large insulated shed. Anyway, big freezer just to make a huge block of ice. Powered overnight from off-peak mains to freeze the block, and then topped up during the day from roof solar panels.

A network of pipes goes through the block of ice, through which air is blown and then the now cool air exhausts into the house at floor level. Hot air from the house is exhausted through the roof.

Would this work as a form of aircon? Assume the house is properly insulated and stuff.

I’ve seen similar systems proposed for large buildings, though they tend to use the cold storage to even out seasonal fluctuations rather than daily fluctuations.

What worries me about your scheme is that a freezer generates heat, the heat created outside the freezer exceeds the cold inside the freezer. So you would run the freezer only when the weather is cold and switch it off when the weather is hot.

I did some CSIRO work on a system that used the latent heat of chemicals other than ice as a passive energy storage mechanism. At night the chemical freezes releasing heat and during the day it melts absorbing heat. The chemical most often seen in the scientific literature is paraffin (or paraffin halides to reduce the fire risk). The second most commonly seen chemicals that can do this are salts that dissolve in their own water of crystallisation. I was looking only at passive energy storages – your idea of adding active energy storage using a freezer is actually a superb idea. Wish I could patent it.

mollwollfumble said:

I’ve seen similar systems proposed for large buildings, though they tend to use the cold storage to even out seasonal fluctuations rather than daily fluctuations.

What worries me about your scheme is that a freezer generates heat, the heat created outside the freezer exceeds the cold inside the freezer. So you would run the freezer only when the weather is cold and switch it off when the weather is hot.

So the freezer needs to be a split system then, with the compressor and other hot parts mounted outside of the freezer room, and only the coolant tubes going inside? Which adds another level of complexity to the engineering of it.

mollwollfumble said:

I’ve seen similar systems proposed for large buildings, though they tend to use the cold storage to even out seasonal fluctuations rather than daily fluctuations.

What worries me about your scheme is that a freezer generates heat, the heat created outside the freezer exceeds the cold inside the freezer. So you would run the freezer only when the weather is cold and switch it off when the weather is hot.

So the freezer needs to be a split system then, with the compressor and other hot parts mounted outside of the freezer room, and only the coolant tubes going inside? Which adds another level of complexity to the engineering of it.

you could use citric acid or ammonium nitrate

when you add citric acid / ammonium nitrate to water it makes the water cold , it’s an endothermic reaction

during the day the water is evaporated by the sun

during the night the citric acid and anmonium nitrate is added to a tank of water where PVC pipes pass air through the mixture, cold water makes cold air

or you could have water slowly dropping into a tank that forms the ceiling

cold air falls from the ceiling during the night

wookiemeister said:

or you could have water slowly dropping into a tank that forms the ceiling

cold air falls from the ceiling during the night

Or wrap the place in hessian, and turn it into a large Coolgardie safe.

Wait…

Isn’t that the principle of evaporative air coolers?

yes. and no good in humid conditions.

or just have a big arse solar system that cools house during the day and makes ice as suggested

JudgeMental said:

yes. and no good in humid conditions.

I use the fans here to cool down. Very humid currently (86% RH). But they work to cool me down. The sweat still evaporates with the breeze. Same principle.

Michael V said:

JudgeMental said:

yes. and no good in humid conditions.

I use the fans here to cool down. Very humid currently (86% RH). But they work to cool me down. The sweat still evaporates with the breeze. Same principle.

you could could have 457 people sponging you down in front of the fan

wookiemeister said:

or just have a big arse solar system that cools house during the day and makes ice as suggested

I have read of a passive zeolite-based system, using the heulandite-laumontite transition, triggered by the sun’s heat.

http://en.wikipedia.org/wiki/Ground-coupled_heat_exchanger

probably one of the most economical.

wookiemeister said:

Michael V said:

JudgeMental said:

yes. and no good in humid conditions.

I use the fans here to cool down. Very humid currently (86% RH). But they work to cool me down. The sweat still evaporates with the breeze. Same principle.

you could could have 457 people sponging you down in front of the fan

All imported nubile nymphettes? I like the thinking.

(All 457 of them? Or should I put them on shifts?)

>The sweat still evaporates with the breeze.

lucky to ‘ave transition

the Chinese have just have been using pipes in the ground to cool air for buildings for summer and warm air for winter

JudgeMental said:

http://en.wikipedia.org/wiki/Ground-coupled_heat_exchanger

probably one of the most economical.

(Without reading the article), that’s what I got installed at the Walgett Police Station in 1979. Coils buried 3 metres into the ground. Public Works were going to install separate air-cons in each room.

:)

alternative energy magazines go on about this method

some bloke buried a heap of PVC pipes in his garden . you just pp air through them

that is it MV. see it used on Grand Designs quite often.

Michael V said:

JudgeMental said:

http://en.wikipedia.org/wiki/Ground-coupled_heat_exchanger

probably one of the most economical.

(Without reading the article), that’s what I got installed at the Walgett Police Station in 1979. Coils buried 3 metres into the ground. Public Works were going to install separate air-cons in each room.

:)

Wrong, sorry.

The system I convinced Public Works to install was one where the heat pump (air-con) evaporator coils (normally, in a split system, in the air with a fan) were buried in the ground. It changed the efficiency of the system from around 4.5:1 to around 8:1. For both heating and cooling.

Using a solar collector to drive a passive absorption refrigeration cycle would have to be the best bang-for-your-buck, but for simplicity and reliability and ease of installation and control etc. etc. a photo-voltaic panel driving an evaporative cooler would be hard to beat.

JudgeMental said:

that is it MV. see it used on Grand Designs quite often.

Pity termites came up with the design first, otherwise we could patent it.

>a photo-voltaic panel driving an evaporative cooler would be hard to beat.

I’d think so. The more lower speed adjustment the better too IMO, if lower speed does the job and uses less power…..for night too if on mains or batteries.

there’s also the possibility of using the mains water pressure and some volume to generate enough energy to drive a fan, water is there anyway for a vap cooler, and the ‘motor’ outlet/pad wetter/bleed can be used for watering

evaporative is useless in humid conditions. geothermal heat pump run by photovoltaics

http://www.pir.sa.gov.au/__data/assets/pdf_file/0008/90944/DirectUseHVAC2.pdf

Geothermal Heating and
Cooling in Australia

i think you’d waste a lot of water to get enough energy out to power a fan.

>i think you’d waste a lot of water to get enough energy out to power a fan.

dunno, discussed briefly previous what you might get from average household supply, but with vap coolers they don’t need to operate with much airflow at all to cool significantly.

in my circumstance, for example, I have three wall mount vap’ aircons, we generally use one at a time. I notice when I switch them off that the slightest breeze through the pads coming in makes very cool air, so will probably try 110V transformers on the fan motors, (not the pumps that wouldn’t work) see if can’t get lowest setting power (all we generally use) from ~160W down to about half that.

we’re on PV with batteries

in our case it is only the evenings in summer sometimes(rarely) when warm that might have us drawing more than wanted on batteries (I get generator going if extended periods), anyway during those same periods I could have the water exiting the water motor on the aircons do my garden watering

some of the added capacity of vap cooler fans is to counter outside breeze in case there’s wind (pressure) on the open window sides….

often I take the restrictors out of the vap cooler bleeds (it flushes them and stops blocks – they don’t have dumpers) and that bleed I run out onto the lawn to do my watering. Might be >1L/min

There are of course other ways to get airflow, convection, and things that face into the breeze.

if you want airflow without pumps on an evaporative then build a tower and let the cool air falling to pull warm air in through the wet pads. you really aren’t going to get any usable power out of water flow.

I guess all we need to do is wait for someone to come up with nuclear fusion to meet our energy needs

>you really aren’t going to get any usable power out of water flow.

there’s some math that needs to be done regards that

we’d average 70psi pressure here, make the flow 1L/min, someone might come along and explain what the maximum power is that can be extracted from that.

so is 70psi = Head of ~ 53 metres? @ flow 1L/min = .0166L/sec = 9Watts theoretically available?

dunno, based on that i’d need >5L/min maybe

so is 70psi = Head of ~ 53 metres? @ flow 1L/min = .0166L/sec = 9Watts theoretically available?

where does the 9 watts come from?

>where does the 9 watts come from?

….. i’m open to suggestions regards what the power available may be.

anyway shuteye time, getting bit cool here too.