Heat Management Within Alternate Realities

[Questor]

Whenever I have to address a real world problem I try to find the easiest low tech means of doing it. In developing the perfect Hybrid cabin cruiser I want to either eliminate or utilize waste heat/energy to the greatest extent possible.

One of the major energy expenditures of cabin cruisers is air conditioning.This leads to the question, " How can I eliminate waste heat without cranking up the air conditioner to do it ?" .

One major source of waste heat is refrigeration. This reminds of a crisis I experienced in my kitchen laboratory last year. During a heat wave the temperature in the kitchen was almost 100 degrees Fahrenheit even though the air conditioner was running full blast. It took me about one minute to realize that the refrigerator was also running non stop. It didn't take long to figure out that the refrigerator was producing more waste heat than the air conditioner could over come.

In that oppressive heat my first thought was to unplug the refrigerator and let the food rot. It didn't take long to realize that I couldn't afford to do that so I decided to figure out why the fridge was running non stop. The problem was that the waste heat was trapped behind the fridge with no where to go. It was too close to the wall and surrounded on all sides by cupboards.

As soon as I moved the fridge about 6 inches from the wall the fridge began to run quieter but continued running non stop. So the next question was," how do I speed up the removal of waste heat so the fridge won't keep putting out heat as it runs non stop? ".

What I decided to try was installing a very low wattage computer cooling fan from a scrap computer. I installed it on top of the refrigerator so that it could pull air out from behind the refrigerator and push it into the room. Within about 2 minutes the refrigerator shut down. Within about 10 minutes the kitchen temperature began to noticeably drop. Within about an hour the air conditioner shut down as well after the kitchen temperature dropped below its setting.

Ever since that day in the kitchen I've been wondering how many billions of dollars are being wasted in North America to fuel wasteful wars between air conditioners and refrigeration equipment. Installing low wattage refrigeration cooling fans that are tied into ventilation ducts leading out of the home ought to be a building code requirement everywhere that air conditioning is considered a necessity.

Sorry mate, but you are really a idiot!
A completely insane person, with a trend to screw up every sensible topic.

[CatBuilder]

Seriously... I'm with Apex1 here.

Other than the compressor motor's heat, there is NO HEAT COMING OUT OF YOUR REFRIGERATOR THAT WASN'T ALREADY IN THE ROOM!

WTF? THINK a thought experiment through for a second before you open your mouth.

What does a refrigerator do? It removes heat from a box and releases it out through the condenser (the grate in the back). Where does the heat in the box come from??? The damn ROOM! Wake up, man. You're really losing it.

If you took the refrigerator out of the room completely, the ONLY difference in heat you would have in the room would be the heat produced by the compressor's electric motor running.

Why did your kitchen overheat? No, it wasn't your meth lab.... it was the fact that you didn't THINK again and ordered an air conditioner without enough BTU's for your room! Learn to do math. It's not as evil as you make it out to be. It can be your friend. It could have saved you a lot of money wasted on the wrong size air conditioner.

These threads really suck.

Where is the little emoticon for shooting yourself in the head? That's how I feel after reading this....

[hoytedow]

If a refrigerator or an air conditioner run all the time it could be a sign that the unit is low on refrigerant or the condensation coils are dirty and need cleaning or there isn't enough clearance for good air circulation to disperse the heat. These are machines and like all machines need periodic maintenance.

[Questor]

Originally Posted by hoytedow

If a refrigerator or an air conditioner run all the time it could be a sign that the unit is low on refrigerant or the condensation coils are dirty and need cleaning or there isn't enough clearance for good air circulation to disperse the heat. These are machines and like all machines need periodic maintenance.

Poor installation design often results in poor airflow behind refrigerators. As the temperature behind a refrigerator rises the compressor must work ever harder in its attempt to remove heat from the refrigerator.All that extra work imposed upon the refrigerator results in more heat being released into the room. While the refrigerator groans under the ever worsening crisis it becomes transformed into more of a kitchen furnace than refrigerator.

Most people that recognize the refrigerators role in a kitchen heat crisis solve the problem by buying more powerful air conditioners. It makes more sense to improve the efficiency of the refrigerator. My small circulating fan uses less than 2 watts of electricity. Whenever I turn on the air conditioner I bring out my little fan.

[powerabout]

did someone miss the fundmental of refrigeration and that is
moving heat from one place to another

[WestVanHan]

Originally Posted by CatBuilder

Other than the compressor motor's heat, there is NO HEAT COMING OUT OF YOUR REFRIGERATOR THAT WASN'T ALREADY IN THE ROOM!


If you took the refrigerator out of the room completely, the ONLY difference in heat you would have in the room would be the heat produced by the compressor's electric motor running.

Perhaps you could explain what happens to a gas that is pressurized??

Freon,after it's gone through the compressor, is about 55 C or 130F.

[Questor]

Originally Posted by WestVanHan

Perhaps you could explain what happens to a gas that is pressurized??

Freon,after it's gone through the compressor, is about 55 C or 130F.

Now you have me tempted to perform an experiment to see how hot it can get behind a refrigerator. I have seen temperatures behind fridges well over 130 degrees Fahrenheit. I've seen drywall behind fridges that was burning hot. Pressurized fluids travelling around corners pick up heat from the additional resistance plus there is the factor of the overworked motor that is in continual operation.

This reminds me of all the people that suggest the best way to cool an over heated kitchen is to leave the refrigerator door open all day. I've never been able to win that argument as they sit in front of the thing with their head inside the fridge.

[powerabout]

Originally Posted by Questor

This reminds me of all the people that suggest the best way to cool an over heated kitchen is to leave the refrigerator door open all day. I've never been able to win that argument as they sit in front of the thing with their head inside the fridge.

The same people that cant get their head around an aircraft has the same glide path regardless of it being heavy or light

[Questor]

Originally Posted by powerabout

did someone miss the fundmental of refrigeration and that is
moving heat from one place to another

Apparently a lot of people have missed the boat when it comes to dealing with the issue of heat generated by refrigerators. It's totally brainless to entrap it with poor circulating potential surrounded on all sides by walls cupboards and whatever else may be on top of the fridge. The longer the heat is trapped in the confined space the harder the fridge works trying to overcome it's own energy as it steadily increases the temperature both in the confined space and the room the fridge is in.

The idiots solution is to buy more air conditioners and burn more electricity to fuel the ongoing wars of both the fridge against itself and the fridge against the air conditioners. It is much more efficient and cheaper to simply ventilate the fridge's heat out of the kitchen while air conditioners are in use.

[WestVanHan]

Originally Posted by Questor

Apparently a lot of people have missed the boat when it comes to dealing with the issue of heat generated by refrigerators. It's totally brainless to entrap it with poor circulating potential surrounded on all sides by walls cupboards and whatever else may be on top of the fridge. The longer the heat is trapped in the confined space the harder the fridge works trying to overcome it's own energy as it steadily increases the temperature both in the confined space and the room the fridge is in.

...a quick post before going fishing.....

All the boats I've seen with larger refrigeration,that are for tropical use,the condensor is either water cooled,or it's been moved out of the cabin.
Gee,wonder why.

That day was 100 degrees...after coming out of the compressor at 130 the gas typically cools to just over 100 at the top....but couldn't...and you're correct in that it was caught in a cycle.

I'd bet the air behind your fridge was 130 to 150....most of which was just radiated back into the rear of your fridge.
Not much would have come in via the closed front.

[CatBuilder]

Originally Posted by WestVanHan

Perhaps you could explain what happens to a gas that is pressurized??

Freon,after it's gone through the compressor, is about 55 C or 130F.

No problem. The heat in the refrigerant after going through the compressor is largely comprised of the heat absorbed while it traveled through the evaporator unit, plus some from the compressor.

As your refrigerant passes through the check valve, it experiences a large pressure drop, which evaporates it. Evaporation allows the refrigerant to take on heat. Re-compressing that vapor into a liquid, the refrigerant will retain that heat it picked up in the evaporator, hopefully, loosing a good amount of it as it passes through the condenser and is returned to a liquid state.

The refrigerant will also have collected heat from the compressor motor and as well as mechanically generated heat from the process.

[CatBuilder]

Originally Posted by WestVanHan

...a quick post before going fishing.....

All the boats I've seen with larger refrigeration,that are for tropical use,the condensor is either water cooled,or it's been moved out of the cabin.
Gee,wonder why.

That day was 100 degrees...after coming out of the compressor at 130 the gas typically cools to just over 100 at the top....but couldn't...and you're correct in that it was caught in a cycle.

I'd bet the air behind your fridge was 130 to 150...which most of just radiated back into the rear of your fridge.

It's all about temperature differences. Of course a condenser will work better if it is colder. His fridge definitely may have had hot air behind it causing a loss in efficiency and a strain on the compressor motor.

However, he said this is what caused his room to be hot and his air conditioner not to work.

That's simply not the case.

The extra heat energy from the refrigerator can, by definition, only as much as the compressor uses in electrical energy. There is no magic creation of heat here, just as there is no magic creation of power from a boat's wake in his other thread.

His air conditioner didn't work because it was sized too small. My guess is his air conditioner wasn't sized for a kitchen, which should always include extra BTUs to cover cooking heat. Discounting the heat from cooking, if he wasn't cooking, than the air conditioner was undersized for his application. The heat the refrigerator made was negligible.

[srimes]

Originally Posted by CatBuilder

However, he said this is what caused his room to be hot and his air conditioner not to work.

That's simply not the case.

The extra heat energy from the refrigerator can, by definition, only as much as the compressor uses in electrical energy. There is no magic creation of heat here, just as there is no magic creation of power from a boat's wake in his other thread.

His air conditioner didn't work because it was sized too small. My guess is his air conditioner wasn't sized for a kitchen, which should always include extra BTUs to cover cooking heat. Discounting the heat from cooking, if he wasn't cooking, than the air conditioner was undersized for his application. The heat the refrigerator made was negligible.

I agree that the a/c was undersized, but it is possible that the refrigerator played a roll is pushing things over the edge. Say the fridge uses 700 watts when running: that's a fair amount of heat, about the same as a space heater on low.

[gonzo]

If you want to make it more efficient, dump the exhaust hot air from the refrigerator outside. A vent would do the trick.