Ecological project home made

[Chris_Workshop]

Hello,

I come here to share my project of air cooler (rather than the inappropriate term of air conditioning but which is however mostly used when we speak of a cooling device) ultra economic but nevertheless effective (at least I hope) manufacturing house from elements mostly recovered. So economical that a solar panel of about 100W will be able to operate it.
Rather than a long talk, here is the exhibition of the principle and the beginning of the work in video. later the fan speed will be managed by an Arduino board.

[Forhorse]

The idea is not bad, we are almost in the concept of the Canadian / Provençal well hydraulic. Too bad it's not generalizable.

[sicetaitsimple]

Why not so effectively we have a large reserve of fresh water, which does not seem to me very common.

That said, I have no idea of ​​the thermohydraulic characteristics of a car fan / radiator assembly. Certainly we can do and look at what it gives, it's an approach. But to calculate the cooling potential under this completely different regime (15 ° water inlet, let's say 25 to 30 ° air inlet) might be a prerequisite. It is still necessary to have at least an order of magnitude of the main values ​​characterizing the equipment (flow rates, exchange surface, etc.).
I'm afraid that even if it works perfectly from a "mechanical" point of view, the thermal performance will be a little disappointing. But that's just a hunch, so much the better if I'm wrong!

[ENERC]

Very good idea!
For sizing: a car that supplies 20 kW of average power to the wheel dissipates at least 20 kW in the radiator for about 60 ° C of temperature variation. (20% of the energy goes into the radiator: https://entretien-voiture.ooreka.fr/ast ... -du-moteur)
If you allow 10 ° C temperature difference in the assembly (from 15 ° to 25 ° C) it is 3 kW anyway.
Let's stay on a power of 2 kW of air conditioning.
You need a water flow of: 2000 / 4.18 / 10 -> 47 grams per second, or 172 liters per hour. The pump will do them widely.
The uncertainty remains on the airflow that is huge in a car as soon as the speed increases.

[Chris_Workshop]

I have already done some calculations.

Regarding the amount of water and its location, it is impossible for it to be heated by the contribution of heat that will be pumped by the radiator.
The temperature of the water will not increase or it will increase infinitesimally. It takes 1 calorie to raise the temperature of 1 gram of water of 1 ° C and 1 calorie = 4,18 joules.
There is 20000 liters of water in the tank. so 2x10 power 7 grams of water. Therefore it takes 83,6 mega joules to raise these 20m3 1 ° C water. That is the equivalent of 23,2 kW.h. This means that it would be necessary to provide a power of 23,2 kW during 1h to raise the temperature of 1 ° C in the tank assuming that it is perfectly isolated. But this reserve is in contact with a surface of 32,5m² of concrete. himself in contact with the ground up to a depth of 5m. So even with such power we would not be able to heat this water in reality.

After the radiator will be far from being able to provide such a thermal power. As far as I'm concerned, I rely on an estimate from the small 7000 BTU air freshener I have at the moment. The air coming out is cooled to 15 ° C precisely. But clearly my system will be very superior. Already the radiator exchange surface of 306 is almost 6x higher than that of the cooler (665x350mm against 220x180mm is 2325cm² against 396cm²). In addition the blower part of the cooler does not break 3 paws to a duck. The 2 306 fan coils clearly stir more air, but then much more. While you hardly feel the breath of the cooler at 1m, you have hair in the wind at the same distance from the fans. So the top I'm quiet.

Another advantage over the cooler, the window will be closed while he needs it to be open to pass the hot air exhaust pipe and to introduce air to compensate for the air coming out of this pipe . Just that, it greatly hampers the performance of the cooler. My system will work all windows closed so.

In spite of all this small cooler of which I speak happens to make pass the temperature of a room of 22m ² of 31 ° C to 27 ° C in 4h. Not so bad. It is given for 7000 BTU (walnut unit which I do not control but which would be equivalent to 0,293W). So a priori but without warranty 7000 BTU correspond to 2051W. Maybe experts will give us details on it. Meanwhile I expect that my system will be at least as good as this little cooler. Therefore if it sends 2kW thermal in the tank it is not near to warm the water that it contains as demonstrated above. These 2000W will be easily distributed in the surrounding soil.

The flow rate of the P 0 delta pump is 1600l / h. Since the rising water column that goes to the radiator will make the same weight as the one going down into the tank we are at delta P 0. Since there will be losses due to pipes and other shrinkage I expect 1200l / h. Either a water velocity in pipes Ø15mm of 1,9m / s approximately. With such a speed, such a flow, there is no need for the pipes to be isolated. They will be cold all the time. And even if it's only half, in reality it will not change anything.

So even if it is not tested in real conditions we can not be completely sure, there is still little suspense in the success of this system.

[sicetaitsimple]

I have already done some calculations.

Regarding the amount of water and its location, it is impossible for it to be heated by the contribution of heat that will be pumped by the radiator.
The temperature of the water will not increase or it will increase infinitesimally. It takes 1 calorie to raise the temperature of 1 gram of water of 1 ° C and 1 calorie = 4,18 joules.
There is 20000 liters of water in the tank. so 2x10 power 7 grams of water. Therefore it takes 83,6 mega joules to raise these 20m3 1 ° C water. That is the equivalent of 23,2 kW.h. This means that it would be necessary to provide a power of 23,2 kW during 1h to raise the temperature of 1 ° C in the tank assuming that it is perfectly isolated. But this reserve is in contact with a surface of 32,5m² of concrete. himself in contact with the ground up to a depth of 5m. So even with such power we would not be able to heat this water in reality.

What do you mean? Let's say that your system, under "nominal" conditions (inlet water at 15 °, air to be seen, but say between 25 and 30 °) has a cooling capacity of 2kW.
On 24h, taking your values, the water temperature of your tank will increase by 2 °, and gradually it will spread in the concrete then the earth by slowing the temperature increase gradient of the water, it still continues to increase if it works several days in a row. And once the concrete and the earth warmer, your water will be hard to cool even if the installation stops.

[ENERC]

Take the case of a land that conducts heat well and keeps 15 ° C around the tank.
Concrete has a conductivity of the order of 1 (1,75 if it is armed).
For 35m2 surface, 5 ° C temperature difference between water and earth and 10 cm thick concrete, it gives:
35 * 5 (° C) * 1 (or 1,75) /0.1 (thickness) -> 1750 W.

Clearly the temperature in the tank will rise, but it will depend a lot on the earth around the tank. If it's wet, no worries.

[Chris_Workshop]

Here the basement is what is called platin, ie strata of limestone. It's hard to dig and it stands alone. But it's a colander. It can rain torrents, it by directly in the basement. So old to make cisterns like mine in time, they dug and then smeared the hole with cement that they put on. And by force it crack where the fact that she flees. Not reinforced concrete but not more than 3 or 4 cms in places.
For digging a cellar, the soil is very wet. When we dig we feel the humidity and the stones are slightly greasy to the touch. This is what type of soil it is:

The water in the tank will not heat up as long as you say it because you are making different assumptions about how the system will work. Today in hot weather, I put my mobile air freshener en route to 19 -20h and I stop at 23h 23h30. That's enough, as I said, to bring the temperature of the room down to 26 27 ° C. I think my system will have comparable performance but in any case there is no question of going below 25 ° C. Therefore he will not turn all the time. And so it will not sway as much kW.h as that per day in the tank water. Moreover the more the delta T decreases between the room temperature and the water temperature, the more the efficiency decreases. Therefore the more he will turn the less he will send calories into the tub. And then we must also take into account that the house is well insulated. 10cm of glass wool on the walls and 25 on the ceiling. So the heat does not come back like that. Once the big effort is made to lower to 25 26 ° C, the rest is maintenance and the power sent into the tank becomes much lower. Moreover the maintenance could imagine by turning the fans very slowly.

[sicetaitsimple]

Of course, if you only plan to use it 3 to 4 hours a day, it's different. But in this case the title changes, it is no longer an air conditioning, it is a "cooler" with limited performance in the event of a prolonged heat wave.
In any case good luck and good success!

[GuyGadebois]

Of course, if you only plan to use it 3 to 4 hours a day, it's different. But in this case the title changes, it is no longer an air conditioning, it is a "cooler" with limited performance in the event of a prolonged heat wave.
In any case good luck and good success!

Nothing to do, air conditioning. It's hot? Ben it's hot, it's cold? Ben it's cold. That's eco (no) logy.