Redundant energy and resource use for household appliances

I've been mulling over the idea of redundant energies and resources for a while now, and dreaming of the ways it could be used to "power" things - or conserve energy. I'm not an engineer or inventor, so I wanted to share these here with your handy people to see if any of these could work - and perhaps if you might have some ideas of your own!

The ideas

1. A fridge using the outside air (in winter) to cool itself. The fridge would have an intake vent to the outside - through a wall. A micro-controller could track temperature both inside and outside of the fridge. When it's cool enough outside, and the fridge requires cooling, the controller could trigger a small fan in the vent to pull cold air into the fridge. I figure powering a micro-controller and a small fan would be a lot more conservative than running the fridge system, although, as I said - I'm not an engineer.

2. A woodstove-top mini-oven. A similar system to the above idea (micro-controller and fan), but using the excess heat of a woodstove or wood furnace to maintain a consistent temperature in a small oven. This could be useful for say - cooking a couple small loaves of bread, or even a single baking tray - using only passive heat energy. The benefits of this over an actual cook stove, would be price and the portability and ability to retro-fit such an appliance.

Notes

I'm thinking the micro-controller is just an easy way to configure a prototype, but I know there's likely an easier/simpler method of opening/closing a vent and running a fan.


Do you have any ideas to utilize redundant energy or resources?

Simon Gooder wrote:
2. A woodstove-top mini-oven.

This might work:  https://www.coleman.com/camp-oven/2000016462.html

Idea 1.
OUR Eco-village on Vancouver Isl. was building homes with cob "cool rooms" that fit your description sort of, although I don't think they were planning to use fans - just airflow. That was almost 10 years ago, so they may have some data for you as to the success or failure of the concept. From your post it sounds like you're heating with wood - just wood? Remember that your fridge "adds" heat to the house when it pumps that heat out of the fridge interior, so if you need some heat to support the house temperature when the wood stove isn't running, it's not a "waste".

Idea 2.
We have a Pacific Energy wood stove. We bought a camping oven - they're flimsy and don't really have the ability to control the heat well. If you've been following the Allerton Abbey upgrades, there's a big difference in the effectiveness of a rocket stove vs a rocket mass heater for doing their designated design tasks. I gave up, because using my electric stove put heat in the house and didn't need to be babied. To change that, I'd need to make a purpose-built mini-oven with some insulation on the top and sides designed to fit the wood stove. (The fact that the wood stove is down a flight of stairs from the kitchen is a factor. I do use the top of the wood stove to preheat pots of water if I'm cooking something like pasta. Again a wood stove *designed* for cooking is a much different thing than one *designed* just for heating.

One thing that pops to mind with the fridge in winter thing is in the winter you want that waste heat from the fridge to do extra work by slightly heating your space.  I think another example are the new heat pump water heaters. They actually act as an air conditioner pulling heat from the room to heat water and as a dehumidifier as well. you can bake on a wood stove already. you put what you want to bake in a pot and raise it above the stove surface a given amount then cover it with a larger pot like a canning pot. You have to experiment to get temperatures right but it works...

I think this is like any kind of heating or cooling; the real gains to be made, is actually in doing the boring stuff.

For instance, a half filled freezer is not as efficient as one that is full. For $1.99 you can go to McDonald's and buy ice that will save about $20 in operating costs in that first month alone...or make your own ice.

Or with a woodstove RMH, pellet stove, etc, after your coffee pot is done brewing, shut it off and leave the decanter on the woodstove RMH, pellet stove, etc to keep it warm instead of letting the burner cycle on and off. Or make cowgirl coffee.

My father took his wood FURNACE (not a woodstove) and ducted it into the back of his electric clothes dryer. When not in use, it was an extra heat register, when in use the electric heater never switched on. That saved a lot of electricity because electricity was just used in flopping the clothes over with the drum.

A block of ice, surrounded by sawdust in a bucket so it will not drip once the ice is melted, will help keep the compressor from coming on in a refrigerator quite so much.

Interesting thoughts! Although There may be some experiments to try with the wood stove/oven add-on, not sure it’s an ideal situation.

Regarding the fridge, while cob house cold room is cool if you have a cob house, I have a fridge. I guess I could just leave my food outside in a Rubbermaid bin to achieve this effect in the winter.

As for Travis’ thoughts on the “full-up freezer” I’ve usually got a full freezer, and I do practice this.

I suppose I’m just thinking of more ways to waste less!

I like the fridge using outside air idea.  I have a rudimentary version with a root cellar in the basement.  It's 34-40 degrees from late October till April.  But we still run our fridge in the kitchen.....  

I think you'd need to build the refrigerator from scratch to make it work.  I believe the freezer compartment and fridge compartment on a "normal" fridge use the same mechanics so if your outside air is 30 degrees the fridge part would be fine but the compressor would still have to run to keep the freezer at 0F.

As for the benefits of the heat from the refrigerator heating your house, I'm thinking there are more efficient ways to add some heat to your house than that.  It's great if it works out to give you cold food and a warm kitchen, but if you had cold food with a fan, the heat could be generated a better way for less electricity.

You would not want to pipe the cold air to the fridge just pipe it to the exterior radiator and increase the refrigeration cycle efficiency. The only way you could pipe the cold air to the fridge would be to get an all fridge unit.  Back in the expensive PV days I had bent the back radiator away from the fridge to add an air gap and shove an inch of foam to increase efficiency. Newer fridges are way better. If you can find an R600 fridge they are even better still.

Good point David!   Would it be even better to modify the radiator piping and have the radiator outside?

personally in the winter time I want every BTU I can in the house. Having said that You could enclose the radiator in sheetmetal and pipe the cold air through it. You have to have some heat though as a lot of compressors don't like the cold.