Residential solar AC - PeachParts Mercedes-Benz Forum

Whiskeydan · #1 08-03-2006, 01:01 PM

There used to be an absorbtion AC unit made by a company called Servell (I think) that was sold thru the gas company yrs ago.
What ever happened to them?

There are small absorption refridgerators and large industrial units but nothing in the 2-5 ton range. I always wondered why.

Is it not possible to make a solar ac unit? Maybe the collectors would be too large, not hot enough???

I seem to recall a co-op housing building in Austin just off campus that was solar heated and cooled back in the late seventies early eighties. Anyone in Austin familiar with this?

I think it would be a nice versitile package if someone manufactured a glycol cooling unit that was absortion based.

All this heat...

Carleton Hughes · #2 08-03-2006, 01:50 PM

Serval,the same folks who make gas and kero fired ammonia absorption fridges and freezers,yes they DID make solar fired AC units for RV's and third world applications but that was 20 years ago,I think I'll search.

cmac2012 · #3 08-03-2006, 01:53 PM

I'm thinking this will be a major growth industry. It only makes sense. The grid gets most stressed during heat waves. You get your solar cooler going when it's needed most, and the parabolic trough mirror types heat oil of some sort which is circulated through a holding tank. The oil gets up to around 7 or 8 hundred degrees and that acts a bit of an energy resorvoir after the sun goes down, and having some cooling function to cool the house of for bedtime would be a plus.

I'll look later for some of the systems I've found before through web searches. There are people out there doing it.

t walgamuth · #4 08-03-2006, 11:07 PM

i have never seen a solar ac unit. but i have heard of gas units. and my tt has a gas/electric refrigerator.

solar is pretty low grade heat though and it takes a good bit of power to produce cold air so i think maybe the size of the collector required might be prohibitive.

tom w

cmac2012 · #5 08-04-2006, 06:38 AM

If you're thinking of photovoltaic cells, it'd be prohibitive. Parabolic mirrors, trough style is my favorite fantasy preference, collect heat, up in the 700 degree range. Absorption style run on heat. More fancy systems also employ pumps.

I have the wattage per square meter somewhere, I'll dig it up later.

t walgamuth · #6 08-04-2006, 07:25 AM

no i wasnt thinking photovoltiac.

that wuld introduce at least one more exchange so some loss would occurr. but the size of the collector would be somewhat comparable. energy is energy.

tom w

cmac2012 · #7 08-04-2006, 04:24 PM

True. According to what I've found, parabolic trough mirror systems can generate 120 to 170 watts per squar meter. So if you had 20 m2 of mirror, about 40 m2 of land space, thats about 20 feet by 20 feet. At the low figure, that'd be 2400 watts. Ten plots like that, 24 Kw. About 100' x 40'. A little bit of land all right but might be worth it.

t walgamuth · #8 08-04-2006, 11:00 PM

so how many watts to run a 3 ton ac unit? that is 36000 btus.

i am guessing about equal to a football feild. heh heh

tom w

cmac2012 · #9 08-05-2006, 12:36 AM

One thing I'm sure of is I don't know a lot about it. What is a 3 ton AC unit used to cool? A hospital or a house?

Could very well be that 30-50 years from now, energy prices will be really high, and heat waves hotter.

I would much rather have at least one room in a house, say the den in a basement -- major earth insulation -- that could be cooled to 60 degrees during the middle of a 110 degree heat wave, 95 at night, than have nothing at all or have a system dependent on the grid.

The billionaire doctor/inventor whose house I helped build lives way up on a hill in Portola Valley, a little bedroom community just west of Palo Alto and Stanford. We built him a workshop, about 20 x 40 off to one side of the house, and the basement contained a 4 cyl. diesel, 270 Kw generator because being at almost the end of the line, they were way vulnerable to brown/black outs. I guess that would run an AC system but imagine if a silent solar system (not THAT solar system) could be built on the hill below his house? I really think there's going to be some money in this.

fz500sel · #10 08-05-2006, 02:15 AM

I've seen a solar powered little fan thingy on tv that you put inside your vehicle when it is parked. The solar power runs a small fan that is supposed to exhaust the hot air inside your vehicle so that when you finally go back into your vehicle it is not unbearably hot. The commercial shows 2 vehicles parked in the same location. 1 has the solar fan the other doesn't. The one without the fan has an internal temp of 107 degrees fahrenheit, while the one with the fan is only a mere 75 degrees.

Anybody ever try this thing? what are your opinions on it?

cmac2012 · #11 08-05-2006, 04:32 AM

Oh man, I hate to admit it, but I was thinking that one might one to buy and I never, but never go for late night ads on cable.

You have to wonder how well it would hold up at that price, what was it $14.95 and it includes the ginzu knife or something?

If I lived inland where you get the kind of hot car like I used to experience in New Mexico, I'd give it a try. Here in the bay, we don't have that many scorching days.

I'm thinking even better would be a factory installed system like that. They're making flexible solar panels now, quite thin also. Put a decent sized one on the roof and have a thermostat inside the car. You could have a little computer brain on it, as soon as inside temps get a few degress over outside temps, the thing would come on and use the normal ventilation system. The solar panel could double as a battery tender, like the ones that come with VWs only more deluxe.

Rick76 · #12 08-05-2006, 06:57 AM

A few years ago I heard that one of the Japanese cars (I believe it was Mazda) had solar panels built into the sunroof to operate a cooling fan. Thought it was a fabulous idea. Not sure which model(s) or year(s).

t walgamuth · #13 08-05-2006, 11:13 AM

yeah, i was thinking it was vw or audi though.

three tons will do a good sized house. here in indiana. maybe 3000 sf plus basement.

tom w

cmac2012 · #14 08-05-2006, 02:44 PM

Quote:

Originally Posted by Rick76

A few years ago I heard that one of the Japanese cars (I believe it was Mazda) had solar panels built into the sunroof to operate a cooling fan. Thought it was a fabulous idea. Not sure which model(s) or year(s).

What?! Someone stole my idea?? Where's my lawyer's phone #...

iwrock · #15 08-05-2006, 03:04 PM

Quote:

Originally Posted by t walgamuth

yeah, i was thinking it was vw or audi though.

three tons will do a good sized house. here in indiana. maybe 3000 sf plus basement.

tom w

It was Mercedes, and they put it on the E, S, and C class. It was called active ventilation. It had super-efficient solar panels built into the roof just in the front of the sun roof.