Hi. We have a place in the Victorian Alps powered by micro-hydro and solar. Long story short: in the middle of summer, when it's in the 40's, we're making 800w to 1kw when the sun is shining, enough for a very low-wattage a/c unit to help one room get through the day. Trouble is, it's nearly impossible to find the power draw in watts of a/c units. Even the retailers have to break a box open and read the darn things. Energy efficiency, BTUs, etc. are indeed important...but watts is too. Does anyone have any suggestions on how to find the lowest wattage a/c unit available in Oz?
Air Conditioning off grid
(45 posts) (18 voices)-
This link shows a very comprehensive discussion about solar powered air conditioning:
http://entropyproduction.blogspot.com/2005/10/solar-thermal-cooling.htmlThermally driven air conditioners could have some advantages. However the limitation is actually getting rid of the heat at the other end of the process.
Posted Saturday 1 Aug 2009 @ 3:10:29 am from IP # -
Sunshine
Memberjeffe01,
Airconditioners with inverter technology are the most efficient.
I find that Airconditioners usually have a maximum current rating, so if you ahve the maximum figure in amps, then you can work out the max power usage.
e.g. my unit is 9.1 amps, so using P=VI, the the power= 240v x 9.1 Amps= 2184wattPosted Saturday 1 Aug 2009 @ 1:38:32 pm from IP # -
ghostgum
MemberIf you are in the Victorian Alps, then at 1000m above sea level, the temperature will be 6-9 degrees cooler than the plains, or about 31-34 degrees C. For this, you don't actually need an air conditioner (at least you don't if you like warm temperatures). Controlling radiant heat (shading over windows etc., radiant barrier in roof) is the first step, if you haven't already done it.
In Victoria, the really hot days have dry air, so an evaporative cooler would also work with the available power, provided you have enough water.
If you have the available space, and are allowed to dig, then a long air pipe buried 2m under the ground will allow you to pull in slightly cooler air.
Posted Sunday 2 Aug 2009 @ 11:43:22 pm from IP # -
In response to jeffe01. If you go to the Australian Government site http://www.energyrating.gov.au and surf your way to the air conditioning section. There is a column for the Energy input in KW. This will tell you what energy is required to run the various units. Generally retail stores do not have this information at there ready. Sites such as ours http://www.1stchoiceairconditioning.com.au do. I find that the more information that you can post for the customer the easier it is for both parties.
Posted Wednesday 19 Aug 2009 @ 8:05:55 pm from IP # -
Air conditioning off grid can cost real money, apparently.
"The amount the U.S. military spends annually on air conditioning in Iraq and Afghanistan: $20.2 billion, according to a former Pentagon official."
http://www.npr.org/2011/06/25/137414737/among-the-costs-of-war-20b-in-air-conditioningI wonder how much air conditioning the Australian contingent in Afghanistan costs?
Posted Wednesday 29 Jun 2011 @ 2:42:21 am from IP # -
From the above site:
Posted Wednesday 29 Jun 2011 @ 3:19:28 am from IP # -
gazmo88
MemberNot actually electric (although if it has pumps it will need a bit of leccie) but these guys:
http://www.solarsatisfaction.com.au/mention this product:
http://www.eco-kinetics.com/solar-products-and-services/solar-air-conditioning.htmland also mention that the ANU are working on an Oz designed solar air conditioner:
http://news.anu.edu.au/?p=912Given that the ANU article was from 2009 the technology has probably been given / sold / stolen, to/by some foreign bunch. Seems to be the way.
The idea _sounds_ good (my kero fridge was fantastic, no moving parts wish I still had it) and one of the problems of a solar array is the excess heat produced in summer if it is sized for winter ......
but I have no idea if any of this really works.
Posted Wednesday 29 Jun 2011 @ 4:16:40 am from IP # -
Jeffbloggs
MemberAir-conditioned tents? I hope they have some sort of insulation in between...even an inflatable one would be better...
Gazmo
Thanks for the links..interesting. It would seem to operate on similar principles to the vortex tube:
http://www.newmantools.com/vortex.htmIt produces both heat and cold, but requires a compressor to achieve this. The question with the Solar AC system is how did they manage to construct a efficient solar thermal compressor?
Posted Wednesday 29 Jun 2011 @ 4:39:54 am from IP # -
gazmo88
MemberSorry, I have no idea how it works.
I assumed it was the same as an old ammonia fridge.
It looks very interesting, but its at the bleeding edge of technology in terms of its marketing which means for sure that both the risks and prices will be high.
Another thing that may be slightly applicable would be this:
http://www.sola-mate.com/
but the cooling would be available at night which would mean your excess solar energy would need to be stored which rather complicates things
Thanks, I'd never heard of that vortex tube thing before.Posted Wednesday 29 Jun 2011 @ 8:34:32 am from IP # -
There is an Australian academic and business group dealing with solar cooling.
http://www.ausscig.org/index.htmlPosted Wednesday 29 Jun 2011 @ 11:00:00 am from IP # -
Thanks to all who have posted replies. My apologies for my tardy response, but for some reason I didn't receive email notices that the discussion was live.
It's 42 degrees outside, so clearly at 650m its bloody hot! Already have well insulated roof, floor (300mm), and 150 mm walls and dual glazed windows, sun shades, and white Corey roof. Stays no hotter than 29 inside on hottest days, but that can still be a tad warm. Already have pushed the limit in terms of new fangled things like graywater , solar, hydro, composting toilet, etc, and tired of battling stuck in the mud councils, workmen, etc, so just wanting an old fashioned AC unit that as efficient as possible. Will keep trying and checking the provided links. Thanks so much to all!
Posted Monday 7 Jan 2013 @ 9:27:29 am from IP # -
wlb
MemberHere's a cut and paste from a reply I made on a similar thread yesterday.
You might find this interesting.
http://us.sanyo.com/HVAC/HVAC-Solar-Integration-Offgrid-SolarIt works very well. I've been corresponding with Dave for a few years and got to know him reasonably well. He experimented with this unit which is theoretically undersized for the job, with Sanyo's (USA) approval. They were satisfied with the results and so honour the warranty.
Unfortunately Sanyo withdrew from the Australian market after the Panasonic takeover a few years ago, and in typical fashion, Panasonic won't comment about a suitable alternative in their local range. A similar unit should also work but it would be without warranty.
I'll be looking into it again for our place, once I've finished my PV system upgrade.
Posted Tuesday 8 Jan 2013 @ 2:46:09 am from IP # -
Jeffbloggs
MemberWowsers this thread has been "asleep" for a long time! It was 2009 when jeffe01 started it and he only got back here in 2013 to take a look if anyone commented? lol that's funny. Time must go really slow up in those Victorian mountains!
One for the record books I think!
Posted Tuesday 8 Jan 2013 @ 3:08:41 am from IP # -
Ok. Ok. The bloody Yank of the Bundar forgot where he posted. I'll be 59 next week. Early Alzhiemers.
Anyway, found that site re Sanyo. Looks like a good solution, as 300 W in am and pm would be fine, and 1100 in the middle of a sunny day, likewise. But googled the crap out of it, to no avail. Long gone, I reckon. So, still stuck with trying to find a split or window system in Oz, where it says the watts it uses (or the amps for that matter, after which I can figure it out X V). Shouldn't take too much to take it from the current 28 tops inside when its 42 outside (I built the damn place well). I did try the 1st choice site, but it seems to be gone. And the Guv. site is, surprise!, very confusing and I couldn't find the info I wanted. Go ahead, laugh away. But if you have an Apple computer question, try me!
Posted Tuesday 8 Jan 2013 @ 3:17:57 am from IP # -
Jeffbloggs
MemberHey Jeff01
No harm intended, I'm not having a go at you. It was meant to be a polite ironic laugh, because typically responses are pretty slow on the forum at times...just not that slow! But on your "watts" of air-con dilemma I'd advise you to purchase a "inverter" type airconditioner which has a variable speed compressor. That way regardless of the maximum current draw it has, you can throttle it down by increasing the temperature setting and the compressor will draw less current accordingly. You can then follow PV output if you monitor them both. Samsung sell good units under $1000 each for the big 8kW output ones, and about $700 for the 3kW output smaller ones. I bought 4 big ones (8kW output) from the Good Guys at $800. I'd go for the smaller one if you have restricted power.
BTW due to the COP typically being around 3 or so you can just divide the output cooling/heating Watts by 3 to get a rough approximation of the watts it consumes to drive the compressor/air-con.
Posted Tuesday 8 Jan 2013 @ 3:38:36 am from IP # -
No harm taken, amigo. I was being ironic, as well! By now this Septic Tank is used to the Aussie sense of humor. Great info on the inverter type etc. If you divide 3kw output by 3, that gets you 1kw, which works for me for only maybe 3 hours a day in summer. And if I can dial it down to 300W early and late, perf! I'll check into it! Thanks!
Posted Tuesday 8 Jan 2013 @ 3:55:57 am from IP # -
Jeffbloggs
MemberNo Probs Jeff01
See maybe it was worth waiting all those years for me to post? lol
All the best.Posted Tuesday 8 Jan 2013 @ 4:02:44 am from IP # -
Buzzman
MemberThis might also be useful:
http://www.youtube.com/watch?v=2FpaSKazhNYOr this might be worth a look:
http://greenprm.com/c.aspx?cid=Solar-Air-ConditioningIt might even be worth looking at boating-related AC units whihc can be 12V or 24V, although most require a cooling water circuit designed as a heat dump, and the circulation pump for these might be an extra current draw too many....
Posted Tuesday 8 Jan 2013 @ 6:29:41 am from IP # -
John Sheridan
MemberCan you power an Air Con directly from the panels, from DC to Ac using an inverter and how much power would you need panel wise and is that safe, like if a cloud went over and the power drops
Posted Wednesday 16 Oct 2013 @ 5:57:48 pm from IP # -
Yep we have batteries and are way off grid. We also have about 1.8kw of pv and also about 200 to 250w of 24 hour a day micro hydro. But neither is enough for the AC units sold in Australia. In the States one can get an AC unit that only draws maybe 750 or 850w. Here, they don't tell you or don't know, but in checking deeper they all seem to draw at least 1200w, even the small window units. That's way too much to run the house, and the AC. So, if I could get a small 240V/50hz window unit that was similar to a US unit, that would work. But the only ones I've found in Oz draw way too much, hence, still seeking.
As for clouds, its pretty much only hot enough when its summer and the sun is out. If it were cloudy, I probably wouldn't need the AC on anyway, as our house is very well insulated and the windows are well shaded. Thanks for the advice, though!
Posted Wednesday 16 Oct 2013 @ 10:05:07 pm from IP # -
David
MemberAh, I have someone that does do AC (he's a fridgie) he does know his stuff, there are a few small split systems that will run on about 800w in Australia, when hes away camping his caravan has an inverter split AC on it which he does run off one of those el-cheapo 900w continuous generators (not inverter type).
As a matter of interest why not add more PV?
Advantage, when you really want to use the A/C is when the sun is most prolific.
It's not that expensive and will enhance production over winter anyway.
you're lucky to have micro-hydro, our new house it's far too flat even for low head.Posted Wednesday 16 Oct 2013 @ 10:28:47 pm from IP # -
David
MemberJohn Sheridan said:
Can you power an Air Con directly from the panels, from DC to Ac using an inverter and how much power would you need panel wise and is that safe, like if a cloud went over and the power dropsNo will not work, battery inverters will not work without batteries & GCI's will not work without a version of the grid available, which if you use the wrong battery inverter that's not designed for AC coupling will become a smoking wreck.
Posted Wednesday 16 Oct 2013 @ 10:35:01 pm from IP # -
If I could find the name and model etc. of that split system at 800w, I'd get it in a heartbeat. If you have any contact info, I'd appreciate it!
Re more PV, adding more PV is of course the ideal solution in an ideal world, especially with prices where they've been. However, Our roof is now full up, which means a ground mount for us. I've been building my place for 13 years, and am pretty much ready to sit back and enjoy for a bit. Digging, pouring cement, building the frame, installing the panels, wiring, BOS bits, etc. just doesn't appeal at present. We have plenty of power for our needs right now, so the easiest thing in my mind is to throw a small AC unit in a window for the 3 hot sunny months, and forget about it the rest of the year. But good question.
Posted Wednesday 16 Oct 2013 @ 11:18:48 pm from IP # -
Benny
MemberThe mitsubishi heavy industry split AC's have been mentioned several times here. I have a 2.5k capacity one that only uses 500W. See data here..
http://www.mhiaa.com.au/index.php/SRK-ZJX-Series.htmlProblem is they seem to have disappeared from the energyrating.gov.au site. Now a Daikin 7star unit comes up top rated.
Posted Thursday 17 Oct 2013 @ 1:45:28 pm from IP # -
John Sheridan
MemberThis one uses 510, it's an In Window box model, but it will cool
http://www.teco.com.au/tww60hfbgjbb
I have the Skinny version, not sure how many watts it uses, never cared, being on grid at the mo0ment.
Posted Friday 18 Oct 2013 @ 6:22:44 pm from IP #
