Saving on A/C Costs

[cfg83]

Arminius -

Originally Posted by Arminius

Oh yeah, the least anyone can do to hypermile their air condioner is make sure it's always in the shade.

http://www.fsec.ucf.edu/en/publicati...SEC-PF-302-96/

Based on this, I went ahead and shaded my South Facing wall AC unit with Coroplast, metal construction brackets, hard disk magnets, and zip ties :



This shows the East facing part of the AC that is exposed. The AC will almost never be on in the morning, so I am not worried about this exposure :



This is the West facing side. It is almost totally covered by an aluminum window shade already, so again, I am not worried about it.



I was lucky because I was able to use hard disk magnets to attach the construction brackets to the AC unit. We have a ton of obsolete hard disks at work (200 MB to 4 GB) from recycled PCs. We needed to wipe the data and/or destroy the hard disk. It's much faster to destroy the disk and extract it's "sweet magnetic nectar" than it is to wipe, so I am breaking them up as needed.

By sheer luck the Seagate hard disk magnets screw holes were an exact match to the construction bracket holes :



The right picture allows you to see the bracket holes.
The left picture shows the magnet attached with screws.

This is not true of all hard disk magnets, but it made life much easier for me.

What is great about the magnets is that I didn't have to drill any holes into the AC unit. If the wind picks up too much, I would think that the coroplast shades would "pop off" and fall to the ground, no biggee. However, I think it's more likely that they would "pop off and back" due to the magnetism.

CarloSW2

[RH77]

HDD magnets are a great idea -- strongest magnets I have laying around too...

With your design, have you looked at the airflow for the condenser? I believe the front of the unit (on the outside) is the outgoing hot-air flow from the condensing coil. If you a fresh-air inlet, I think the fins on the side pull that in (optional and not the most efficient setting).

Have you checked for the warm air flow by the front panel? Otherwise, the shade would help. I think one of the links earlier showed a spray with red dye for for unit's stand-alone unit's exhaust fan (the amount of air flow is considerable -- it nearly reached the top of the test home.

I thought about some sort of shading as well, but I'm afraid of choking the flow. It would have to be a tall, awkward looking fence -- but that unit sure bakes (near the Southwest corner with no shade protection). Hopefully the mist is doing something other than scaling the living daylights out of it!

RH77

[ttoyoda]

cfg83
Are you running the ac unit while this sunshade is on?
If so I would suggest that you place the shade away from the condenser at least the diagonal size of the condenser, preferably further. Also, avoid any arrangement that will allow hot air from the condenser to come back around and be sucked in again.

[cfg83]

RH77 -

Originally Posted by RH77

HDD magnets are a great idea -- strongest magnets I have laying around too...

With your design, have you looked at the airflow for the condenser? I believe the front of the unit (on the outside) is the outgoing hot-air flow from the condensing coil. ...

Not yet, I don't want to turn on the $AC$ until I have too. Hrrmmmmmmm, now I wonder if the venting heat will melt the coroplast. Doubtfull, but maybe I need to turn it on under test/monitoring conditions.

... If you a fresh-air inlet, I think the fins on the side pull that in (optional and not the most efficient setting).

I always set the fresh air inlet to draw air from the inside because it will only be on when it is hotter outside. That would be easy to test, however.

Have you checked for the warm air flow by the front panel? Otherwise, the shade would help. I think one of the links earlier showed a spray with red dye for for unit's stand-alone unit's exhaust fan (the amount of air flow is considerable -- it nearly reached the top of the test home.

I thought about some sort of shading as well, but I'm afraid of choking the flow. It would have to be a tall, awkward looking fence -- but that unit sure bakes (near the Southwest corner with no shade protection). Hopefully the mist is doing something other than scaling the living daylights out of it!

RH77

I think (not at home right now) my unit is an 18,000 BTU (1.5 ton) AC unit, so I don't think the flow will be toooooo great. I may increase the space of the vertical panel (see how it angles down and in), but I did the vertical panel last and was a bit more lazy towards the end of the setup.

Ha ha, I just realized I *could* go techno-designer insane if I wanted to. The Coroplast comes with "channels" that could be circulating water. I'll bet it would get dirty/clogged in no time, however.

CarloSW2

[cfg83]

ttoyoda -

Originally Posted by ttoyoda

cfg83
Are you running the ac unit while this sunshade is on?
If so I would suggest that you place the shade away from the condenser at least the diagonal size of the condenser, preferably further. Also, avoid any arrangement that will allow hot air from the condenser to come back around and be sucked in again.

Not sure what you mean by "diagonal size". I can't do anything about the angled aluminum window shading unless I get rid of it completely (it came with the house). I can create more space with the vertical coroplast. It can have more space at the bottom.

I can also buy more spacers and stack them, doubling the effective gap between the coroplast and the AC.

CarloSW2

[Arminius]

Nice job on the shading, cfg83!

[ttoyoda]

Not sure what you mean by "diagonal size". I can't do anything about the angled aluminum window shading unless I get rid of it completely (it came with the house). I can create more space with the vertical coroplast. It can have more space at the bottom.

Sorry, I mean that if you were to measure the diagonal size of the AC unit, like you measure the diagonal size of a TV screen, that you should be at least that far away with any shade. I cannot tell the scale of the AC unit in the photos so I am just scaling from the size of the AC unit. The awning seems OK to me.

[LaneLester]

This thread has me thinking of a way to use the three large solar panels I bought for the Y2K scare (I admit it, I was scared). I have them connected to a controller and four big batteries (two of which have died). I'm thinking I could position the panels to shade the compressor and also drive something (fan? water pump?) to help the compressor. I could lose the batteries since I would only want the thing working when the sun was shining.

Lane

[Tooelecherokee]

I just built a Shade for my AC unit - PVC pipe and shade cloth - looks like it is keeping it about 2Deg cooler in the shade now.. hopefully that will help I have a fin comb in the mail so that I can straighten out the fins that my 3 year old has pressed over and get even better efficiency out of it. I don't know that I would want to spray my system with water the water here is very hard and vinegar doesn't touch it

[cfg83]

LaneLester -

Originally Posted by LaneLester

This thread has me thinking of a way to use the three large solar panels I bought for the Y2K scare (I admit it, I was scared). I have them connected to a controller and four big batteries (two of which have died). I'm thinking I could position the panels to shade the compressor and also drive something (fan? water pump?) to help the compressor. I could lose the batteries since I would only want the thing working when the sun was shining.

Lane

What a cool idea! I have an old Unisolar flexible panel. I should attach a fan to help my AC also.

CarloSW2