Building shade structure for home ac condenser?

[ds549]

dont think it would help much , your still pullin in the same temp air and if a shedcut down on airflow it would defeat the purpose.

[Stormin Mormon]

Did you read the article on the web site (Link posted a couple days ago)?

It did mention hot air recirc.

[Gideon]

Great idea. That reminds me of the marginally-educated kid working at a retail store about a decade ago. He came up to "help and advise" me when I was looking over power inverters.

He explained to me that they convert 12v DC battery power to

120v AC power. Duh. He also explained his secret idea for unlimited free power: 1) Buy a large 12v battery, a large inverter and a large battery charger. (You see where we are heading already). 2) Hook them in the obvious loop - Inverter attached to battery, battery charger plugged into inverter, and the battery hooked up to the battery charger. Wow! Now he would use the second 120v outlet from the inverter to power anything that he wanted With free power!!

Gideon

[Gideon]

Al,

There is considerable debate about the benefits of shading, although I feel that it is helpful for a few reasons:

1) Modest energy savings which could add up considerably over years. 2) Apperance. A nice screen or planting looks better than than the AC unit.

Keep in mind that factories can often build something better and less expensively than you and I can do on our own. If you decide to add a screen, then consider doing a Google search. I found this quickly, which shows an $80 reasonably attractive unit from Target, on sale now for $40:

Y

It has redwood coloring and a lattice design. The posts have pointed ends which can be driven into the ground. The item description is "Air Conditioner Screen - Natural", which will help you if you have trouble with the link I provided above.

Forty dollars plus shipping. Even if you just get 1% energy savings, you have to come out ahead on the purchase.

Good luck, Gideon

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Thanks, Al Kondo

[Gideon]

Edwin,

I couldn't agree more. The savings from shading may be modest, but Walter's statement is poorly worded at best and poor science at its worst. I assume that he just didn't phrase his reply carefully this time.

A unit located in the sun is constantly picking up thermal energy from the sun. That heat negatively impacts AC operating cost, although there are questions about how much.

Imagine 3 AC outdoor units:

1) The first has a steady mist of cold water hitting the entire exterior of the case. The cold water plus the thermal losses from evaporation cool the case considerably. This is an extreme simulation of "negative solar heating." 2) A normal unit located outdoors. 3) A unit with "modest-BTU" flames hitting all four sides. Point four contractor propane heaters (jet engine style) at the 4 sides of the unit. This is an extreme simulation of solar heating. Provide ambient air from a protected source and path so that it is not being impacted by the heaters.

Which unit will operate most efficiently? Obviously, unit #1 which simulates "negative solar radiation." Next is unit #2. Worst is unit #3 which simulates extreme solar radiation.

Situations 1 and 3 above are extremes, but they illustrate the fact that one cannot honestly say that "efficiency of the condenser is solely dependent on the temperature of the ambient air." It may very well be possible to say "direct solar input on the unit is trivial compared to ambient air temperatures", but that is a very different scientific statement.

Personally, I believe that gains from proper shading are modest (1%-10%), but they are still relatively free and may also add cosmetic benefits. I'm hoping to install a new AC system this year and I'll go with the obvious choice - locating the compressor unit on the North side of the house instead of the back (East) of the house. That is quieter, better looking and certainly has to offer some minor but significant energy savings.

Regarding the study on the impact of shading, it is important to remember that this was a small study conducted by a university.

I interact on a continual basis with university professors and I know that some have a lot of common sense and are good at research. I also know that a lot of them don't know their ass from a hole in the ground and are radically out of touch with the real world. I live in a neighborhood full of PhD types and I spend a lot of time helping them get their lawn mowers started in the Spring, adjusting carbs, examining brakes on the car, helping them avoid getting ripped off my mechanics & contractors, etc. I'm no smarter than the regulars on this newsgroup, but I feel like a DIY genius next to many university types.

One engineer on our street didn't understand why the trash collectors aren't allowed to pick up dehumidifiers. When I mentioned freon and the (alleged) destruction of the ozone layer, he said "yes, but that is for refrigerators and air conditioners. A dehumidifier doesn't need freon." Duh. He is currently having problems with his Harley, which now leaks gasoline out of the carb when it is running. The problem started after he had a performance shop "soup up" his bike. I told him that this is a common problem on Harleys after a new camshaft is installed and the factory original manifold is still on the machine. The overlap between intake and exhaust valves has been radically changed and raw gasoline is getting blown back through the short manifold. My overeducated neighbor won't believe that and prefers to believe the mechanics who say "We didn't break your Harley. Give us a blank check and a couple of weeks and we'll fix it."

Sorry about rambling so much. I'm just saying that you shouldn't believe every over-educated nerd out there. And don't automatically accept every university study as gospel.

One additional point - if the air conditioning is derived from a heat pump setup which provides some or all heating in the winter, then I'd suggest installing one of the following:

1) Deciduous plantings which will drop their leaves in the fall and allow solar input on the unit in the Winter. 2) A wooden screen which can be easily removed and stored in the shed over Winter. You don't want solar input in the cooling season; you do want it in the heating season.

Gideon

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Did the laws of physics change?

Your conclusion that it does not save much may be correct, but your reasoning is incorrect. The sun will cause the condenser and any exposed fins to pick up some heat. The sun has been doing that for many years now. The only question is how much heat is gained and how much can be saved by shading and is there a payback. .

[Chris Lewis]

According to Gideon :

I'd also add in lifespan. In some cases, ie: bright hot sun on plastic parts, shading it may give it a bit longer life.