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Solar Air Cond

PostPosted: Mon Dec 30, 2013 2:34 pm
by treechange
Hi did several search's here but found no info about them. I read an article that stated a 30% saving in power running costs. Does anyone have real world experience with these, or no more about them. We are planning to build a new house and something like this sounds promising.

Nig :D

Re: Solar Air Cond

PostPosted: Mon Dec 30, 2013 5:43 pm
by Gordon-Loomberah
The best air conditioners to use when off-grid are one of the newer 2-2.5kW reverse cycle inverter units with COP/EER in the 5-6 range. The only solar AC units I have heard of are nowhere near that efficient.

You want the maximum cooling and heating for the energy used, so avoid gimmicks that dont deliver the efficiency.

I'm using solar hydronics for heating ATM, the only energy required is for a fan and the pump, but I will be adding some heat from a wetback wood fired stove at some stage. Pics in my intro thread.

Re: Solar Air Cond

PostPosted: Mon Dec 30, 2013 10:58 pm
by treechange
Thanks for the info.

I should have said that it would be used for cooling only, as all heating will he handled by wood

Nig

Re: Solar Air Cond

PostPosted: Tue Dec 31, 2013 8:03 am
by Windaroo Resort
We tested those ac's with a solar panel (so called) attached side by side with a standard inverter model. We logged temps and power usage. At the end of the day we concluded the solar one was a gimmick but people buy them :o

Re: Solar Air Cond

PostPosted: Tue Dec 31, 2013 2:28 pm
by treechange
Thanks for the info, I will give them a miss.

I need to work out if it is better to use several spilt systems or a ducted to cool the house.

Any thoughts :D

Re: Solar Air Cond

PostPosted: Tue Dec 31, 2013 3:41 pm
by Gordon-Loomberah
Use several 2-2.5kW high COP/EER split units, ducted won't be anywhere near as efficient.

Re: Solar Air Cond

PostPosted: Tue Dec 31, 2013 5:13 pm
by bpratt
treechange wrote:I need to work out if it is better to use several spilt systems or a ducted to cool the house.



Go the extra split systems, much more efficient overall.

Most ducted suck from the one location for the entire house, so you really can't isolate different rooms off, even if they talk about different zones on the ducted.

Re: Solar Air Cond

PostPosted: Wed Jan 08, 2014 6:02 pm
by swampdweller
Definitely split systems with wall or ceiling mounted indoor units will be more efficient. Ducted systems use extra fan energy to overcome air friction in the duct system, and in addition there is always some heat transfer between the duct and the roof or crawl space it is installed in, so the unit has to work harder to overcome this. Duct heat gain (or loss if on heating cycle) can be quite significant. You should also consider 'multi-split' units with 3 or 4 indoor heads on a single outdoor inverter unit, as an alternative to multiple split systems.

As a former air conditioning designer and refrigeration mechanic I have examined the thermodynamic principles of 'solar air conditioners' and asked questions of their promoters as to how they actually work. (I.e., the ones which look like and ordinary aircon with an extra solar panel looking arrangement stuck on somewhere). No promoter has yet given an acceptable answer and these units simply cannot do what they claim, at lease not on cooling cycle. Go for a reputable mainstream brand inverter unit.

Real solar air conditioners can be built using absorbtion cooling or dessicant/evaporative cooling technology with solar (hot water) collectors, but they still really in the development arena at present and are very bulky, complex and expensive. You might also consider indirect evaporative cooling for a low energy option which provides cooling performance similar to refrigerated aircon, quite a simple machine, but still not cheap and a bit bulky. For an example, visit the Seeley International website and click on the Climate wizard icon. The residential unit may not be available as yet, but if you're a bit of a pioneer you might be able to talk to them about running a test bed!

Re: Solar Air Cond

PostPosted: Wed Jan 08, 2014 6:03 pm
by swampdweller
p.s., agree with all other comments above.

Re: Solar Air Cond

PostPosted: Wed Jan 08, 2014 10:33 pm
by Chaff_Cutter
Hi Guys and Gals!, :D

Was looking at these DC compressors, assuming you know a good fridgey?

http://www.masterflux.com/products/sierra/

Plenty of figures in plenty of pdf's but no efficiencys...hmmmm

Plenty of choice, and variable speed, brushless DC motors, etc etc etc

Scotty