Oh got it Bruce. Compression systems shift heat (or “coolth”) from one place to another. The energy cost to do so ends up being a fraction of the heat moved in terms of watts/joules/etc.
A good example is a basic resistance heater which is COP of 1, meaning 500 watts into the heater makes 500 watts of heat. A mini split might use that same 500 watts to make 1500 watts of heat. It’ll be hotter inside but the outside part of the mini will get cold. You are “pumping” heat rather than “making” it with compression systems.
Well the two systems need some modifications to bring them to more affordable off grid usability. When Matt gets his system worked out, it will provide a source of mechanical refrigeration. Propane fuel is too expensive for an absorption fridge. Matt’s setup should bring the cost down below a grid powered fridge. Also capitalization costs should be cheaper than a grid machine. Buy a used camper with fridge, buy a Matt-o-meter, find free wood for charcoal, and viola, a non grid, mechanical system, operating cheaper then grid.
Now on the other hand, using butane brings the cost of a wood gas powered vapor compression system down below grid too. Vapor-compression components are everywhere and free. Just about every car has a belt drive pump…the trouble has been evacuating the system and rearranging the components to suit the users needs, then refilling with expensive refrigerant. I definitely see some fun experiments on the horizon. Gotta find a source of butane up here tho.
The Norcold I have is the middle road mid sized fridge. Its a good sized fridge not one of those small compact things. I pretty much only run the LP for this fridge. This has a dishwater and it heats its own water so no need to run the hot water heater except for showering. The 40 tank will last three to four weeks. It basically cost about 40 bucks a month in energy cost.
What is the temperature range of the heat source that the absorption fridges need to operate? (specifically the RV ones by like dometic) I don’t think it is super hot, but could you run it on say from the hot water heater?
I’m replying to myself. It looks the dometic uses R717 (refrigeration grade ammonia) at 14-16" of water or roughly 235 psi, which appears to bring the boiling point of ammonia to around 100C. Which is low grade heat, but too hot for a water heater. it is a low pressure steam system.
I don’t know if they are added CO2 or H2O to it to the refrigerant.
On the bright side, if matt can use waste heat to power the fridge, he could in theory also use it for an AC unit, thus he can stay nice n cool all summer. (I’m not implying, he isn’t cool already).
Nice! and yup the more gas that is the used the more charcoal that is produced. So I want this thing constantly running to make as much charcoal as possible to sustain both gas and electric daily.
Summer months use it drive AC to keep cool, winter months, use it for gas heating to stay warm. Then run all other gas appliances in-between, the fridge, on demand hot water heater, stove / oven and clothes dryer. All it has to do is produce a full hopper load for the DFX-S3 daily and that will give 4 hours run time on the 4375 generator. That is enough for a full charge the run the RV 24 / 7. All I need to power is lights and light appliance like the coffee pot, PC, guitar amp etc. Run all the big stuff on gas and anything that has a gas counterpart. Less batteries needed for storage, smaller inverter, smaller charger, smaller generator, smaller gasifier etc.
You could run the coffee pot on steam I was going to make a smart ass comment about moving to an acoustic guitar… But in reality the amp is important. I didn’t quite dump the guitar amp, but I am using a $10 guitar to usb adapter (the $5 ones don’t have the preamp) so I can use guitar-ix software which attempts to model various amps and sound effects then use headphones or reroute it back through the amp.
I was going to make a smart ass comment about moving to an acoustic guitar… But in reality the amp is important. I didn’t quite dump the guitar amp, but I am using a $10 guitar to usb adapter (the $5 ones don’t have the preamp) so I can use guitar-ix software which attempts to model various amps and sound effects then use headphones or reroute it back through the amp.