Microwave heating

Post in 'The Green Room' started by Ehouse, Apr 13, 2012.

  1. Ehouse

    Ehouse
    Expand Collapse
    Minister of Fire

    Joined:
    Jul 22, 2011
    Messages:
    906
    Likes Received:
    256
    Loc:
    Upstate NY
    While participating in the below thread on electric resistance heat, I happened across a mint condition Amana Radar Range microwave oven from the 50's in a junk shop and it got me thinking. A quick google search turned up industrial apps. and some heating pads and pet beds, but nothing on domestic heating. Does anyone know of any attempts to use this technology for home heating?

    Ehouse
     
    Collapse Signature Expand Signature

    Helpful Sponsor Ads!





  2. Adabiviak

    Adabiviak
    Expand Collapse
    Feeling the Heat

    Joined:
    Dec 7, 2008
    Messages:
    295
    Likes Received:
    22
    Loc:
    Sierra Nevadas, California
    I don't, but I'm thinking that's because it's a little inefficient? You get quick localized heating at the cost of some of this efficiency, so applying it to one's entire house seems like it'd be a little wasteful over the long term. That said, I have never designed a system like that, so I suppose it could be done? Run sub-floor water through a microwave system instead of some other heat exchanger? Those heating pads and pet beds were meant to be put in the microwave and then be taken out while hot, no? They weren't using live microwaves, correct?
     
  3. jimbom

    jimbom
    Expand Collapse
    Combustion Analyzer

    Joined:
    Dec 19, 2010
    Messages:
    1,022
    Likes Received:
    21
    Loc:
    Missouri Ozarks
    Imagine a very well insulated box. Water pipe passes through the box. The water is heated in the box. Electric is supplied to the box. So we have cool water and electricity entering the box and warm water exiting. Since the box is well insulated, there is little loss. So the problem becomes the lowest life cycle cost of changing electrical energy into thermal energy.
     
    Collapse Signature Expand Signature
  4. begreen

    begreen
    Expand Collapse
    Mooderator
    Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    59,193
    Likes Received:
    7,339
    Loc:
    South Puget Sound, WA
    Oh heck, we're organic. Just nuke the interior for 15 second intervals. That will keep you warm. lol But be sure to wear a nylon belt and remove all rings, watches, etc.

    PS: don't do this if you have metal fillings, pacemaker, etc.
     
    Collapse Signature Expand Signature
  5. Ehouse

    Ehouse
    Expand Collapse
    Minister of Fire

    Joined:
    Jul 22, 2011
    Messages:
    906
    Likes Received:
    256
    Loc:
    Upstate NY
    I went to Wikipedia and found this breakdown; at 1100 watts input 700watts of energy is transferred to the food (water) for an efficiency of 64%. 400 watts is dissipated as heat. A Scientific American article lists different efficiency nos. and says an electric stove top burner is slightly more efficient at bringing water to a boil. If some or all of that waste heat could be returned to the system it should improve matters. So, here's a hypothetical system:

    water enters microwave
    microwave heats water /waste heat is used to preheat water supply.
    water is moved to holding tank
    water is circulated through slab for radiant heating
    water returns to microwave being preheated before arrival
    repeat.

    I suspect this would not be as efficient as a regular electric water heater, however there might be other benefits such as faster recovery time.

    I know, I know, I'm looking for a free lunch again. Can't help it.

    Ehouse
     
    Collapse Signature Expand Signature
  6. peakbagger

    peakbagger
    Expand Collapse
    Minister of Fire

    Joined:
    Jul 11, 2008
    Messages:
    2,295
    Likes Received:
    438
    Loc:
    Northern NH
    I heard that the workers at the defense early warning stations in the artic used to stand in front of the dishes to warm up.

    Realistically the Bio-coal plant being built in Maine supposedly uses microwaves to cook the wood
     
    Collapse Signature Expand Signature
  7. Delta-T

    Delta-T
    Expand Collapse
    Minister of Fire

    Joined:
    Feb 27, 2008
    Messages:
    3,144
    Likes Received:
    579
    Loc:
    NH
    there is a tv show my wife likes ...1000 ways to die, who had a story of a gent who would do that, and fell asleep in the dish...woke up dead.
     
    Collapse Signature Expand Signature
  8. Armoured

    Armoured
    Expand Collapse
    New Member

    Joined:
    Feb 6, 2012
    Messages:
    94
    Likes Received:
    5
    Loc:
    Russia
    I believe microwaves work very efficiently and quickly with modest concentrations of water, because they excite those molecules in preference to others. This just happens to coincide with many types of food.

    Once you switch to things that are pure water or mostly water, they're still quick (because fairly powerful) but not especially efficient. As I understand it...
     

Share This Page

Entire Site copyright © 1995-2016 - email to webinfo@hearth.com
Hearth.com and HearthNet are property and trademarks of Hearth.com LLC Advertising Information