I am not an engineer, so I don’t know if any of the suggestions posted would be worthwhile from a cost/efficiency standpoint.
I do know that the fridge is the single most expensive appliance to run in the typical home ( I assume because it runs 24/7 ). If moving the motor or adding a vent adds even a small gain in efficiency, the aggregate energy savings would be huge.
Whats with the assertion that heat rises? From what I recall from thermo dynamics, heat is transfered by conduction, convection and radiation. Rising was not mentioned.
I will paste a brief quote,
“All the heat from the motor rises - right by and through the area you’re trying to cool.”
I do recall hearing something about warmer air being less dense than the cooler stuff. This could create a slight updraft at the back of the unit that would remove more heat from the coils via convection. However since a properly functioning fridge is airtight, infiltration through the case is unlikely.
Insulation is used to address the conduction route. Fact is the coils at the back are shedding all their heat inches away from the steel outer shell. I would hazard a guess that the machines are engineered with a couple extra inches of fiberglass near these troublesome hot spots.
[Whats with the assertion that heat rises? From what I recall from thermo dynamics, heat is transfered by conduction, convection and radiation. Rising was not mentioned.
]
this is natural convection. this is what cools the coils, I think the motor/compressor has a built in fan, which would be forced convection, but if not would also use natural convection. the air would probally enter from the front, heat from the motor, make a bend at the back, heat further on the coils and float away to heat your house and home. The driving force if it is all natrual convection is the heating of the coils causing a boyant force upwards
[3)The heat from the fridge is not hotter than the ambient air?
Well, since that’s going to happen only a few days a year, no matter where you live, on those days the heat won’t rise. It will be as now. ]
for an a/c to work, the temp of the coils must be higher then the temp of the surrounding media
I think the question is not raising the ref. efficency but keeping the inside of the house cooler in the summer.
I don’t know much about appliances, but I know my new refrigerator was vented because I had to pay extra and saw them work on the roof.
It’s built into the matching cupboards, and looks like the pantry doors, with carved wood and “faux” opalglass “window panes”.
Huge, with a full top-to-bottom freezer side-by-side. I love it.
I’m hoping that this is just a misunderstanding of syntax. While heat itself does not rise, a hot fluid most certainly rises. Ever see a hot air balloon? Same principle. Hot air is less dense than cold air, and thus it will rise off the coils on the back of the fridge. The whole foundation of free convection, as stated by k2dave.
Sailor, I agree with your estimate on differential fridge power consumption, in that it would be low. I guess what I and others are asking is, in addition to that, how much more heat does the A/C need to remove in a ducted vs. non-ducted system? That’s the thing that would be interesting to calculate.
off topic: jamshid, moving the water heater would require redesigning and rebuilding the (large) house because it is gas fired and needs a flue. In any case it would still be in the basement and I am two stories up.
A refrigerator that is built into the cabinets, needs to be vented,but I would think it is vented to the kitchen and not outdoors.
My refrigerator, although not of that type, is (sort of vented in this sense: A fan moves the air along a circuit all under the refrigerator. The air is sucked in from the lower right, goes by the condenser, then the fan, then it is blown over the compressor to cool it and finally over the evaporation tray where the condensate drips and comes out the lower left. So you could enclose this all around s long as you do not block the lower front part.
Well, I think we have pretty much exhausted this topic.
>> how much more heat does the A/C need to remove in a ducted vs. non-ducted system?
Oh, well, off the top of my head let memake up some numbers. My fridge 250W * 0.4 (duty cycle) = 100 W
If your AC has a COP of 2.5 then it requires 40 w to pump that heat out.
AC in the kitchen is a bad idea because of the heat generated by the cooking. You’d need a huge AC to keep the kitchen cool while cooking. better not cook in hot weather 
looks like I’m flogging a dead horse with this one…
Like Sailor said, refrigerators do have fans cooling the compressor and condensor coils. At least mine does; I had to replace the fan motor last year.
Barney111, the load from a refrigerator isn’t that big of a part of a utility bill, at least not mine. If it was, then my electricity bill wouldn’t go up by about 300-400 percent in the summer, this in a small house. If your fridge runs 24/7, I’d have it checked out.
The fact is, a fridge is a very well-built icebox before it’s a fridge; refrigerators don’t need to pump out that much heat. If they did, your kitchen would feel warm near the fridge just as it’s hotter outside near the air conditioning unit.
k2dave elaborates my point quite well. It is not heat that is rising but heated air. This is not mearly a matter of syntax and a re-read of my post will show I do understand how a ballon works.
This reminds me of a simple question that had a simple answer, but a complex explanation.
Q: If heat rises, then why is it cold on the tops of mountains?
A: Heat doesn’t rise.
Good Lord. Where have you seen this? I’ve never seen this in my life, people actually put their refrigerators outside?
Zuma,
You mean to say you’ve never seen a reefer full of beer in a carport?
I pity you.
Everybody knows the heat vents are at the bottom so your toes will stay warm while you’re looking for the leftovers!
[>> how much more heat does the A/C need to remove in a ducted vs. non-ducted system?
Oh, well, off the top of my head let memake up some numbers. My fridge 250W * 0.4 (duty cycle) = 100 W
If your AC has a COP of 2.5 then it requires 40 w to pump that heat out.
AC in the kitchen is a bad idea because of the heat generated by the cooking. You’d need a huge AC to keep the kitchen cool while cooking. better not cook in hot weather ]
I believe the COP (Coeff. of performance) means how much heat is transfered using in this case 250 watts when the compressor is running, but maby someone else can verify thaT
so while the compressor is running you are consumming 250 W of power which gets converted into heat, you are also pumping out an additional 40W of heat. (are you sure that’s all the power a fridge requires?)
Power in + Heat in ----> [heat pump] ----> heat out
the duty cycle refers to the time on average the compressor is running, which I guess would be higher in the summer in a un A/C’ed kitchen then in a A/C’ed kitchen or in the winter.
on a hot day the duty cycle might be more like 0.8, but this is just a guess.
[This reminds me of a simple question that had a simple answer, but a complex explanation.
Q: If heat rises, then why is it cold on the tops of mountains?
A: Heat doesn’t rise]
CSA: (Counter short answer:)
most heat on earth is generated by the sun. The sun radiated the heat in the form of EM radiation. some of the EM is absorbed/reflected by the upper atmosphere. most of the rest passed through the remaining atmssphere where it hits the ground and is absorbed. The ground heats up. Air passing over this ground heats up close to the surface, heating it more then the air above. (note any mtns provide not enough surface area to allow much heating since the air is allways moving). the air at the bottom starts having a boyant force while the cool air wants to sink. how is happens could result in an inversion (not mixing) or a tornado (sudden, violent mixing) or stages inbetween
cornflakes:
I didn’t say that the operating costs of a refrigerator was going to break anyone. I just said it was the most expensive-to-run appliance in the house. And it doesrun 24/7 in the sense that you don’t turn it off and on, like a toaster or a coffee machine.
k2dave, a 250w appliance with a 40% duty cycle generates an average of 100w. To pump 100w out of the room, a heat pump with a COP of 2.5 would use 40w. It can’t get much simpler than that.