The war between the refrigerator and the furnace

HamRadioRocks · Heavy Crude Joined: Jul 19, 2006 Posts: 106

Everyone knows that running the furnace expends energy directly, since energy (in the form of natural gas, heating oil, propane, wood, or other fuel) is needed for the furnace to work. But there's a secondary effect. The warmer your home is, the more electricity your refrigerator needs to keep the contents inside cold. That's because the refrigerator has to chill the incoming air, and the warmer the inflow is, the greater the energy needed to chill it down.

In other words, there's a neverending war going on between the furnace and the refrigerator, and the result is increased energy use. The furnace is working to heat the air while the refrigerator is working to chill the air.

Thus, lowering the thermostat in winter saves energy in two ways: less energy to run the furnace and less energy to run the refrigerator. Using a programmable thermostat to lower the thermostat further at certain times will extend the energy savings.

I wish there were a way a refrigerator could tap into outdoor air in winter. Since the outside air is cold and dry during most of the winter, little or no energy would be needed to chill it. Also, being able to vent the refrigerator's outflow of hot air to the outdoors in summer would save energy by reducing the energy needed by the air conditioner AND the refrigerator to cool the air.

ohanian · Light Sweet Crude Joined: Oct 17, 2004 Posts: 1023

Your logic is flawed.

Here is why. Imagine that your house does not have a refrigerator. Now your furnace have to work HARDER to make your house warm because an item which gives off heat is missing in your house.

SchroedingersCat · Heavy Crude Joined: May 26, 2005 Posts: 460

Houses used to have a storage cupboard that could be vented to the outside in cold weather. In the winter this was the fridge. Don't know why that ever went away.

I've wondered why commercial places don't do this with the huge coolers for beverages.
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dooberheim

Some large HVAVC systems have "economisers", which are outside air vents that can be used to add to heat or cooling air flows.

Turning down the thermostat will help save energy. In many cases, particularly if you acclimatize and heat with wood, you can completely dispense with the furnace, which solves the problem the other way.

DK
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pstarr

Concerned · Light Sweet Crude Joined: Sep 23, 2004 Posts: 1434

Tanada

If I ever have the financial where with all I want to build an integrated fridge, run the coolant through a heat exchanger to pre-heat the water heater supply tank. The Fridge efficiency goes way up as the coolant/water exchanger is way more efficient than the coolant/air exchanger on the back of a standard fridge. The water heater efficieny also goes up as the water inflow is slightly warmed before heating.
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Concerned · Light Sweet Crude Joined: Sep 23, 2004 Posts: 1434

dunewalker

I agree with ShroedingersCat and pstarr. Living off-grid here in the desert, saving energy in any way conceivable is important. So, I built a cabinet for the fridge, put a sealed door on it, drilled two 4" holes in the floor, one in the upper wall behind the fridge, screened them. Now the fridge is unplugged for most of the winter, as the temps have run to minus 6 degrees F. Ironically, the fridge keeps things inside it from freezing. In the summer, I just keep the cabinet door open & since it's on the northeast side of the cabin, it assists ventilation/cooling. Of cours the fridge is plugged in then, but there is plenty of solar power available during the long days of summer to run it.

TreeFarmer · Heavy Crude Joined: Jun 26, 2007 Posts: 137

Ham it seems like you are taking two separate ideas and trying to meld them into one post. If I understand what you are asking, here is my take on it.

As for the "war" between the furnace and the refrigerator, during the winter this does not matter. You need to heat your home so the "war" only results in your getting some of your heat from your refrigerator and thus needing less heat from your furnace.

Now, when you don't need to heat your house (summer) then the refrigerator acts like a heater by transferring heat from within the refrigerator to outside of the refrigerator plus any heat created from the friction of the refrigerator motor and compressor.

You also mentioned lowering the thermostat in your house, this would be an energy saving move because a cooler house uses less energy to stay at a lower temperature when heating is needed. In this case, your furnace would run less and yes even your refrigerator would run less.

You know, if you use AC in the summer, moving your refrigerator onto your back porch would reduce the amount of work your AC would need to do.

TF

Hagakure_Leofman

This relates to 'cool cupboards'. I think david holmgren had an innovative method of cooling some of his food storage cupboards.

From memory, he installed pipes that ran beneath the soil in his glasshouse and off through the building structure to his cupboards. As the plants were watered, the air in the pipes would cool and circulate through to his cupboards.

Something like that.

I've got a storage room that I'm going to vent from beneath the house (cooler air) and a hot air vent out through the roof. Unfortunately, no basement. Any other methods of cooling these kinds of rooms are invited!

smallpoxgirl · Moderator Joined: Nov 08, 2004 Posts: 4220

snax · Tar Sands Joined: Jan 20, 2007 Posts: 68

On that note, one thing people can and should do to reduce the load on refrigeration is acclimate it's contents if necessary before putting them inside of it.

It is more efficient to let ambient outside temperatures or even the AC system do the cooling than any point of use consumer refrigerator.

shaunpagan

In the house I moved out of 1 1/2 years ago, I built a system that would exchange the heat in my fridge with the cold air outside. I built it out of computer water cooling, beer making, and aquarium parts. The energy usage of my fridge dropped to 1/20th of it's normal use. The fridge would still need to kick on in order to keep the freezer cold, though.

The system I built used a device called a thermo cube. This is a little device that only turns power on when the temperature is below freezing. This went out side. I didn't want my system to operate if the temperature outside was warmer than freezing.

If the temperature was below freezing outside, it would turn on. In the fridge, I had a thermostatically controlled outlet that I purchased from a beer making company. I would set this to 36 degrees and I set the regular fridge temp to 39 degrees.

Inside the fridge and outside, I had two matching radiators with computer fans attached to them. When the fridge called to be cooled, an aquarium pump would circulate glycol (I know, bad inside a fridge) from the fridge through a hole I cut in the back of my fridge, through insulated tubing, to the outside of my house where I had the other radiator. The glycol would then pass back in to the fridge colder than it started.

The best part was that the system was absolutely quiet. The only sound that could be heard was when the fridge was open, the computer fan could be heard.

WisJim