MEDIA WORKERS AND TV RESEARCHERS - Please seek permission before posting on this site or approaching individuals found here by phone or email - write to the Editor - mail to nick@off-grid.net


Home Forums General Discussion convert propane fridge to solar

This topic contains 3 replies, has 2 voices, and was last updated by  elnav 6 years, 11 months ago.

Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
    Posts
  • #36642

    elnav
    Member

    Has anyone tried to convert a propane or three way RV fridge to straight solar?

    These fridges do not have a compressor but rely instead on burning propane to create heat for vaporization or electric heaters when plugged into the grid or a battery. The core portion could be heated by concentrated sunlight to heat the refrigerant to the vaporization point. Many area s with abundant sunlight also happen to be in desert area with cool nights. Given adequate insulation these fridges could keep the interior cool overnight and provide cooling during the warmer daytime when refrigeration is needed.

    #40901

    Arkayvee
    Participant

    I know this is an old post, but I have been looking at this

    myself out of curiosity.

    It sounds like you could collect enough heat energy from solar to run

    the absorption cycle, because you are heating ammonia water under

    pressure, just enough to make the ammonia boil out, but not the water.

    The critical temperature of ammonia is around 271 deg F, so it has

    to be less than that, or the ammonia won’t liquefy at any pressure.

    Here is a reference to a paper on a solar powered heat pump that uses

    the ammonia absorption cycle:

    http://tinyurl.com/2azv6f8

    I didn’t buy the paper cause I am cheap, but there it is.

    I think the main problem in getting it to work practically would be

    some way to “throttle” the energy to provide a consistent, steady

    heat source (like a propane burner) to make the ammonia absorption

    cycle run efficiently. That implies some heat storage/heat exchange

    system. Most storage mechanisms that would store that kind of heat

    would be complicated and bulky, compared to carrying a bottle of propane.

    For a fixed installation, however, it might be doable.

    BTW, this is my first post and I am irritated by the damned Amazon ad

    that floats over and blocks the right side of the posting block in my browser

    (Firefox, Ubuntu Linux, 1024×768 resolution LCD). I am having to manually

    size the width so I can see what I am typing. Hope it is readable.

    #40902

    Arkayvee
    Participant

    OK, should have looked some more, a guy has patented the process:

    http://www.freepatentsonline.com/4744224.html

    He uses solar to boil ammonia from ammonia water during the day, to separate out and store up liquid ammonia, then at night he releases the liquid ammonia to perform the refrigeration part by the ammonia turning to gas. Then he runs the gaseous ammonia through water to recover it/absorb it (forming ammonia water) and store it, then the cycle repeats the next day.

    #40904

    elnav
    Member

    Hey Arkyvee I know what you mean because I have the same problem on my Ubuntu machine. Welcome to windoze oriented programming. I complained to web management two months ago about this nonsense but evidently to no avail.

    Real energy conscious people already know Ubuntu runs less energy compared to wondoze because of fewer computation cycles needed for same task but evvidently this is not a priority for a website directed to off grid and energy conserving people.

    As for the patented cycle. He is only able to patent the specific cycle.

    Regarding modulating the heat on a solar driven device. Try shading with blinkers. As long as the reflected or focussed sun rays can exceed the temp needed to boil the ammonia it should work. Practicality suggest this system is best used to freeze blocks or bottles of ice that in turn is used for retaining cold in an ice chest like arrangement if you store food in there.

Viewing 4 posts - 1 through 4 (of 4 total)

You must be logged in to reply to this topic.