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Marmite the Dog

How feasible would it me to design a heat exchange system to cool houses in the tropics?

We have these systems for heating houses in the UK, but they can also be used to cool. The only problem is that the UK systems use a fairly specialist manifold system, which I think would be too complicated and too expensive for this part of the world. Simplify this and I think you could have a winner.

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watterinja

If it's ok with you, I'll set up a separate heat-pump thread & we can explore the ways the technology can be used.

A byproduct of a air-to-water heat-pump, is that while the water is being heated, the byproduct is cold air which can actually be used to cool a house. In Asia, this is a neat trick, that means you can both heat water for say hotels, homes, as well as providing some cooling load.

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Loy Toy

My mate and I were discussing this topic just last week.

All you need is a;

1. A water tower, a water tank or better still a swimming pool.
2. 2 second hand car radiators.
3. A large fan.
4. Some insulated pipe.
5. And a small electric water pump.

Don't want to give too much away but we are confident we can achieve an air temperature of 22 degrees celcius and that is cool enough for me!

Thetyim

^
Please tell me more
I got everything except #2 & #4

I'm listening

lom

Remove all electric wiring from you aircon's outdoor unit.
Put the unit in your hot water tank.

DrivingForce

better than second hand car radiators would be second hand A/C condensers, they're larger air surface area and can pass more water through the unit but have a better density per square inch for heating/cooling transfer.. ideally if the fans still work you could use them for the same purpose as their design and just use the entire portion of that unit.

If there is a shaded source of water a small simple sump pump would suffice for the water pump and some quick disconnect compression hose end fittings would make it a useful, convenient and professional looking installation.. anyway carry on...

watterinja

If you're referring to aircon condensers (non automotive), then your statement is in error.

Automotive radiator fins have air-side heat-transfer coefficients around 250 W/m2.K, whereas A/C fins are closer to 100 W/m2.K, depending on fin pattern. Air-side heat-transfer dominates an air-liquid heat-exchanger in the ratio 80:20.

A good radiator will perform well, if matched with the correct fan. Don't use an air face velocity of more than 2 m/s if you want to minimise fan power consumption.

Loy Toy

I will keep you posted Thety!

We envisage massive savings with regard to installation costs not to mention electrical energy savings.

watterinja

Be interested to see what your calculated heat-load requirements are. You may find some surprises. Cooling air in a space requires a fair bit of heat-transfer. The air often feels cold on touching the skin, but is not enough to overcome the various room heat-losses & pull-down requirement.

Watch also things like humidity, post cooling & condensation inside the house.

Norton

Sounds like what I had in the US many years ago. Called it a swamp cooler.

El Gibbon

I have also used this type of device in the Arizona and California deserts... The key to optimum usability is a very low ambient humidity something not readily found here in the southern reaches. Might work in the hottest areas of dry Issan though.

Spectacular results were achieved in Arizona even in midday 104 deg. F.

E. G.

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Loy Toy

^^ All of those dynamic reactions have to the considered mate and I am sure the prototype instalation will be modified and according to the results. Bit of fun really and between 2 common sense driven novices.

I will keep you posted also and I appreciate your advice!

^^ Pretty much as we see it but pumping the cool air through floor vents and possibly have cooling pipes in the wall cavities.

We will try various arrangements and piping configurations but firstly will spend our time determining what air temperature consistancy we can achieve and also considering condensation levels.

Norton

watterinja

^^ When you're ready, please advise on your COP.

Norton

Have no advice. I know naught about the thermal characteristics and the like. I do know they are cheaper than air con on energy use but air con does a better job of cooling.

watterinja

That's why I asked for the COP of the system.

It could turn out - horror - to be far worse than an aircon system.

DrivingForce

especially in humid climbs these units are far more efficient in dryer climbs such as deserts where the humidity isn't high enough for the A/C to work effectively.

Norton

As I remember, swamp coolers work well in dry climate 30% humidity range. I had one when I lived in the Mojave Desert and it did cool the house. In high humidity like Thailand I don't think they are very efficient.

Marmite the Dog

I was thinking along the lines of a geo-thermal system, as I'm not a fan of Legionnaire's Disease.

watterinja

A very, very valid point.

What are your thoughts on a geo-thermal system?