got a new fridge, learned an energy saving tip from the old one

oil pan 4 · 09-01-13, 01:47 PM

So we got a new refrigerator.

The old one was rated to use $60 a year in power, but I think those were 1993 dollars.

What I learned upon decommissioning the old fridge:
Part of the problem with the old one was its insolation had started getting saturated with water, because after I cleaned it out, unplugged it and let it sit with doors open for a day it started popping and cracking as if large chunks of ice were thawing and expanding, then soon enough it dripping from everywhere it seemed like.
Then when I thought it was done I put the hand truck under it and tilted and started to move it water started running out the refrigerator door seem.

So if your refrigerator, deep freeze, or fridge converted deep freeze has been in service more than a few years you may want to consider working out something to where you can put all your foods elsewhere, unplug it and let it sit with doors open and a catch pan under it for several days if not a week.
Setting it out side in direct sunlight during summer would be best.

This fridge is a lot bigger than the old one, freezer is much bigger, this should allow me to clean out the deep freeze put everything in the new unit and unplug the deep freeze and mothball it, that will save a good bit of power. (I hate deep freezes, my girl loves them for some reason)

Now that the new unit has been up and running for a few days I am going to install one of my Kill-A-watt meters to get a base line for power usage.

Once I get a base line I would like to mod it to make it more efficient.
Main thing I am thinking is wrap it with something to keep the heat out, but it cant be too ugly.

Also I might raise it up off the floor a few inches and see if that will allow for better condenser air flow, if so I figure it will reduce dust build in the condenser and give me enough room to clean under the fridge.

Daox · 09-10-13, 12:01 PM

So, how is the new fridge working out? What kinda power is it sucking down?

chantling · 09-10-13, 06:35 PM

Before you spend any money on insulating materials, you might want to try whatever you've got on hand first, even if it's ugly, to make sure you'll actually save energy. I recently wrapped mine in the foil-faced 3/4" polyiso sheeting, figuring that the foil side out would almost look like stainless (if the lights are off and you squint a bit) and if it didn't work out I could use the sheets on the solar water heater I'm never going to start.

Took 2 and a half sheets to wrap everything but the doors. Doesn't look too bad, although it's fairly obvious. I ran the fridge on the Kill-A-Watt for 3 weeks prior to get a baseline, then ran it for 2 weeks after wrapping it before comparing the readings. If there's a difference in energy usage, it's so small as to be almost imperceptible. After the first week energy usage was up slightly; after the second week it was down slightly. I can't find the numbers now, but it was something like .12 a month saved, and I couldn't be sure usage wouldn't bounce back up again after another week. The slight savings might have been random noise in the data. At $45 for three sheets, that's an extremely long ROI.

I was extremely surprised, as the refrigerator sides were always very cold to the touch, so much so that they sometimes had condensation on them. I fully expected some very decent savings. I was careful not to block the airflow, and the shell itself is very well sealed. Don't know what the issue is. I think very old fridges would benefit from this more than newer models. YMMV.

Daox · 09-12-13, 08:40 AM

Chantling, would you mind starting a thread showing us how you modified your fridge?

AC_Hacker · 09-12-13, 10:26 AM

Quote:

Originally Posted by oil pan 4

Main thing I am thinking is wrap it with something to keep the heat out, but it cant be too ugly.

Before you start wrapping your new refrigerator, look behind it to see if there are external condenser coils, where it can dump heat energy. If no coils there, check to see if they are down in the compressor area. If they aren't there, then they are built into the walls, back and top of your unit. These areas will not feel warm unless your compressor has been running a bit. I have an IR non-contact thermometer (Harbor Freight $10) and when my unit has been running a while, these areas are very easy to measure.

If you wrap a refrigerator that has internal coils, you will drastically lower its efficiency.

-AC_Hacker

Daox · 10-09-13, 10:23 AM

Any updates on how the new fridge is doing?

oil pan 4 · 10-11-13, 01:15 AM

This is not a large external condenser unit.
I wanted one with a large passive condenser but the only fridges that still have this are small apartment size fridges.

For the first few days the new fridge was using around 2kwh a day. I have not reset the kill-a-watt meter and over the last month the average has dropped below 1kwh a day.
It takes at least several days to cool all foam I think.

I did raise the new fridge up off the floor a few inches, simply left the underside hand truck protectors from the factory installed.

stevehull · 10-11-13, 09:07 AM

Had to buy a new chest freezer for my livestock business (grass fed grass finished beef). Bought one (25 cubic feet) that claims to only use $65 worth of annual electricity (computed at $0.012 per kWhr). And yes, the side of the freezer where the compressor is gets hot as the coils are just underneath the metal "skin" of the freezer.

I got out our LDR infrared imager and saw that the top edge of the front, sides and back, for the top foot also have these coils. Nothing on the top or bottom of the unit.

So, the project is to put some two inch "pink board" (closed cell foam) underneath it and on top. This is a significant fraction of the total surface area (35%) and I can get scraps of the foam from projects we do at no cost. Will just tape it down on the lid top and put the freezer on top of the foam. This will add significantly to the R value and the cost is almost nothing.

I was thinking of measuring the kWs used before and after the addition of the top and bottom foam, but lifting a full freezer off the foam just ain't 'gonna happen! Furthermore, the freezer is in the garage and the outside air temp varies widely at this time of year.

My question - do you think I should put in shims on the four corners on the bottom of the freezer to prevent collapse of the foam board? I put about 600 lbs. of beef in it (freezer weight about 150 lbs.) this comes out to a load of about 42 lbs. per sq. foot. My feeling is that the foam will not collapse . . . .

Steve

Daox · 10-11-13, 09:30 AM

You should start a thread on the freezer mod when you get to it Steve.

I am quite sure the foam will be fine without any support.

oil pan 4 · 10-11-13, 11:33 PM

Yes always establish a base line. Once I need to use the kill-a-watt meter some where else I will put the base line data on the back of the fridge in magic marker because I am not going to remember the base line 5 or 10 years from now.

09-01-13, 01:47 PM	#1
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	got a new fridge, learned an energy saving tip from the old one So we got a new refrigerator. The old one was rated to use $60 a year in power, but I think those were 1993 dollars. What I learned upon decommissioning the old fridge: Part of the problem with the old one was its insolation had started getting saturated with water, because after I cleaned it out, unplugged it and let it sit with doors open for a day it started popping and cracking as if large chunks of ice were thawing and expanding, then soon enough it dripping from everywhere it seemed like. Then when I thought it was done I put the hand truck under it and tilted and started to move it water started running out the refrigerator door seem. So if your refrigerator, deep freeze, or fridge converted deep freeze has been in service more than a few years you may want to consider working out something to where you can put all your foods elsewhere, unplug it and let it sit with doors open and a catch pan under it for several days if not a week. Setting it out side in direct sunlight during summer would be best. This fridge is a lot bigger than the old one, freezer is much bigger, this should allow me to clean out the deep freeze put everything in the new unit and unplug the deep freeze and mothball it, that will save a good bit of power. (I hate deep freezes, my girl loves them for some reason) Now that the new unit has been up and running for a few days I am going to install one of my Kill-A-watt meters to get a base line for power usage. Once I get a base line I would like to mod it to make it more efficient. Main thing I am thinking is wrap it with something to keep the heat out, but it cant be too ugly. Also I might raise it up off the floor a few inches and see if that will allow for better condenser air flow, if so I figure it will reduce dust build in the condenser and give me enough room to clean under the fridge.

09-10-13, 12:01 PM	#2
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	So, how is the new fridge working out? What kinda power is it sucking down? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

09-12-13, 08:40 AM	#4
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Chantling, would you mind starting a thread showing us how you modified your fridge? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-09-13, 10:23 AM	#6
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Any updates on how the new fridge is doing? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-11-13, 09:07 AM	#8
stevehull Steve Hull Join Date: Dec 2012 Location: hilly, tree covered Arcadia, OK USA Posts: 826 Thanks: 241 Thanked 165 Times in 123 Posts	Had to buy a new chest freezer for my livestock business (grass fed grass finished beef). Bought one (25 cubic feet) that claims to only use $65 worth of annual electricity (computed at $0.012 per kWhr). And yes, the side of the freezer where the compressor is gets hot as the coils are just underneath the metal "skin" of the freezer. I got out our LDR infrared imager and saw that the top edge of the front, sides and back, for the top foot also have these coils. Nothing on the top or bottom of the unit. So, the project is to put some two inch "pink board" (closed cell foam) underneath it and on top. This is a significant fraction of the total surface area (35%) and I can get scraps of the foam from projects we do at no cost. Will just tape it down on the lid top and put the freezer on top of the foam. This will add significantly to the R value and the cost is almost nothing. I was thinking of measuring the kWs used before and after the addition of the top and bottom foam, but lifting a full freezer off the foam just ain't 'gonna happen! Furthermore, the freezer is in the garage and the outside air temp varies widely at this time of year. My question - do you think I should put in shims on the four corners on the bottom of the freezer to prevent collapse of the foam board? I put about 600 lbs. of beef in it (freezer weight about 150 lbs.) this comes out to a load of about 42 lbs. per sq. foot. My feeling is that the foam will not collapse . . . . Steve __________________ consulting on geothermal heating/cooling & rational energy use since 1990

09-10-13, 06:35 PM	#3
chantling Lurking Renovator Join Date: Sep 2013 Location: Florida Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	Before you spend any money on insulating materials, you might want to try whatever you've got on hand first, even if it's ugly, to make sure you'll actually save energy. I recently wrapped mine in the foil-faced 3/4" polyiso sheeting, figuring that the foil side out would almost look like stainless (if the lights are off and you squint a bit) and if it didn't work out I could use the sheets on the solar water heater I'm never going to start. Took 2 and a half sheets to wrap everything but the doors. Doesn't look too bad, although it's fairly obvious. I ran the fridge on the Kill-A-Watt for 3 weeks prior to get a baseline, then ran it for 2 weeks after wrapping it before comparing the readings. If there's a difference in energy usage, it's so small as to be almost imperceptible. After the first week energy usage was up slightly; after the second week it was down slightly. I can't find the numbers now, but it was something like .12 a month saved, and I couldn't be sure usage wouldn't bounce back up again after another week. The slight savings might have been random noise in the data. At $45 for three sheets, that's an extremely long ROI. I was extremely surprised, as the refrigerator sides were always very cold to the touch, so much so that they sometimes had condensation on them. I fully expected some very decent savings. I was careful not to block the airflow, and the shell itself is very well sealed. Don't know what the issue is. I think very old fridges would benefit from this more than newer models. YMMV.

10-11-13, 01:15 AM	#7
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	This is not a large external condenser unit. I wanted one with a large passive condenser but the only fridges that still have this are small apartment size fridges. For the first few days the new fridge was using around 2kwh a day. I have not reset the kill-a-watt meter and over the last month the average has dropped below 1kwh a day. It takes at least several days to cool all foam I think. I did raise the new fridge up off the floor a few inches, simply left the underside hand truck protectors from the factory installed.

10-11-13, 09:30 AM	#9
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	You should start a thread on the freezer mod when you get to it Steve. I am quite sure the foam will be fine without any support. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-11-13, 11:33 PM	#10
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	Yes always establish a base line. Once I need to use the kill-a-watt meter some where else I will put the base line data on the back of the fridge in magic marker because I am not going to remember the base line 5 or 10 years from now.