Absorption air con?

[Bill]

I have been wondering about the posibility of an air-conditioner which works on the same principle as a 3-way fridge. Does anybody know if such things exist?

 

If they do it will solve two problems. The small one of finding an energy source when away from hookup. And the big one of complaints from She Who Must Be Obeyed about compressor noise.

 

 

 

[Guest starspirit]

I have heard of a thing called a heat pump which is basically a refrigeration plant in reverse as it takes warmth from the air outside your home and pumps the heat into the house.

 

I don't recall the details but in the early 80's a friend had a system and he reckoned it worked - although I also recall when he moved he didn't get another, and then we lost touch or I would ask him.

 

I suppose the theory is good but the running costs and internal inefficienies might make it not cost effective - I don't know but I'm sure someone on here does!

[Derek Uzzell]

Bill: If you are asking whether there's a motorhome air-conditioning unit that will run off LPG, then I'm pretty sure the answer is No.

 

There are models that will run off 12V and/or 230V (and some apparently use the heat-pump principle), but, realistically, all of these will require a mains hook-up (or generator) when the motorhome has been 'sited'.

[Bill]

Many thanks for your replies. I was indeed – as Derek suspected - looking for an air con that would work off LPG (or similar).

 

The answer seems to be No, which is rather what I suspected. I'm surprised nobody makes such things as, given the numbers of us northern greyheads who head off to the Med in our dotage, I should have thought there would have been a good market.

 

Incidentally, all fridges and air cons are heat pumps, irrespective of how they achieve that result. Heat, like water, will not flow “uphill”. It will flow only from a hot place to a cold place so, if you want it to go the other way (e.g. from the interior of a fridge to the outside world) you have to pump it.

 

I won't bore you with the physics, but if the difference in absolute temperature (i.e. in degrees Kelvin, not Centigrade) between the source and the sink is only a small percentage of the sink temperature then you can move huge quantities of heat with the application of only a small amount of energy. That means that heat pumps are by far the most energy-efficient way of heating buildings. Unfortunately they are expensive to buy and maintain, so are not money-efficient.

 

Nevertheless, in places like New York which have hot summers as well as cold winters they often use their air cons “in reverse” in winter. The logic is that if you want air con in summer you have to accept the costs involved, so you may as well have the benefit in winter.

 

 

 

[boobabsca]

Hi Bill,

i've been looking into this air-con a little too (although not with that much knowledge!) and am seriously thinking of purchasing a 9000Btu portable air-con unit from Argos for about £160. This favours very well with the cost of fixed air con of around £1300 (not sure of Btu of that though).

 

I'm not fully decided as i'm concerned i'll be for ever moving the thing out of my way.

 

Where are you up to on your quest of Air-con?

 

 

 

 

[tonyishuk]

Be a little wary when you start the aircon using French campsite supply. the startup amperage may trip the supply. (dependimg on what the site have to offer 5 amp may be iffy, 10 amp I suspect will be OK)

[Brian Kirby]

Bill

I think the nearest you'll find are the evaporator type coolers, that blow air over a damp matrix of some sort to get the benefit of evaporative cooling.  They'll all make noise, because the air has to be shifted around by fans, and whatever folk say, fans make noise.  However, they are generally cheaper, and of much lower energy consumption (albeit less efficient at cooling), than aircon units.  The main problem seems to be having to install a water reservoir to keep the matrix damp, and the fact that the cooled air is inevitably more humid than ambient.

The best solution overall, really, is to get your van into evening shade.  That way it will start the night that bit cooler.  If you can get mid-day shade as well, so much the better!  Then, siesta time from 12 - 16:00, stay up till at least midnight, and get up fairly early while it's still cool(ish!).  Or, move North! :-)