Hello

schuimpge

Hello All, after reading a lot here, finally signed up.
Living in Thailand and just starting to get my feet wet in solar and other energy projects.

Living in a town house, so limited space but my goal is to have 2-3kw system somewhere next year.

But my first project will be a bit different and for that I hope some people here can help validate my idea.

Airconditioner..we all know the basics of it, evaporator, cool gas going in the compressor...comes out as a hot gas, the condenser then cools it to a liquid state, goes through an expansion valve and becomes gas again taking up heat to do so.

Now, to help the compressor and condenser, is it possible to use a Peltier-Device.
The hot side connected just before the compressor...heating up the gas to much higher temperature.
The cold side will be connected to the first 1/3rd of the condenser to help cool down the coolant-gas to liquid..

The device can be driven by a battery and solar. Compressor has much less work to do, so your electric bill goes down.
The device should switch on and off with the compressor, so a relay should connect the Peltier circuit on and off.

Hope some people can comment on the idea...

Thanks and regards,
Luc

waynefromnscanada

Re: Hello

Welcome to the forum "schuimpge"
Your idea is a great one - - unfortunately, Peltier devices are very inefficient and most of the solar electric energy needed to run them would be wasted. Compressor type refrigeration is far more efficient. Beyond that, to intentionally preheat the refrigerant gas before it enters the compressor would only make the whole system work harder.
To get some useful gain from your proposed solar array you'd be far better off to use that solar energy to either run your present air conditioner, or if that system is too big, then to run a smaller one which would take some load off the main unit.

schuimpge

Re: Hello

Hello Waine,
Thanks for the reply. I am still toying around with the idea...definitely appreciate your feedback...hope to see your feedback again...

I initially thought of a peltier device aircon, but read indeed that they are very inefficient. But hen started to look at the air conditioning workings and the various phases for the gas. That's how I got initially looking at solar assist systems. They heat the gas but do that after the compressor, not before. So then my thought was to cool the line before the compressor but that's also not right.
Today searched a bit more, and Wikipedia when you search for 'Economizer' told me what I thought of.
Pre-Compressor needs heat....post compressor needs cooling. That's where I thought of the Peltier device again.

Now, I already thought that doing it before the compressor without a pressure valve might cause trouble, because the heated gas will push both ways.....stopping the flow of gas. But in that case,...how about only super heating the gas After the compressor (as a solar assisted aircon does).. The cold side of the Peltier can than be cooled and the cold air pumped around to the evaporator same like the compressor line going there?

Cheers...
Luc

schuimpge

Re: Hello

See, My reasoning here is...normal aircons compress the gas which is then cooled down to liquid state in the condenser coil before it gets to the decompression valve. This normally happens in the last third of the coil.
Solar assist units basically heat the gas after the compressor to such temperature that it turns to a liquid state in the first third of the condenser coil already, which is claimed to reduce the need for the compressor to work as hard as without the assist.

Based on that, if I heat the condenser coil just after the compressor, with a Peltier unit... I would do the same as a solar assist panel.
But the added benefit is that I have a cool side to take care of, which I can route into the evaporator in the house, where it helps cool the room. Small water hose and pump releasing additional cold air into the room.

So I would reach my desired cool temperature faster, thus decreasing my power needs for the aircon...

solar_dave

Re: Hello

I have no experience with this but there are a few companies out there that use a heating collector to increase the efficiency.

http://www.atlantissolar.com/ac_details.html
http://www.solargreen.net.au/solar-thermal-air-conditioners.html