How Much Gas Shoulda Fridge Use ?

Discussion in 'Motorhome Chat' started by Yorick, Jun 26, 2015.

  1. Yorick

    Yorick Funster

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    Yesterday I weighed the gs bottle then used the Dometic fridge for 24 hours and it used 3 lbs :(

    That was from outside temp (17c) down to 4c. So I suppose it may use a little less the next 24 hours.

    But, and a big but, it will soon be used in the much warmer climes of Spain and Lanzarote. I will be using the solar panels to power it during some of the day, but will still need to use gas overnight. I reckon about half and half.

    I have a 7kg bottle and 4.5 Kg bottle so about 25 lbs, so not gonna last long really

    Maybe it will make more sense to buy a 150w folding solar panel ? I am about to fit a split charge relay, but that will only work on long journeys. We don't plan to do many miles in Lanzarote

    Mucho gracias for all advice :)
     
  2. John Laidler

    John Laidler Funster

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    I think you will struggle even with an extra solar panel. Three-way fridges are not very efficient on electric so apart from it probably won't cool very well the fridge itself might need say something like 120W to work. The answer, not very helpful perhaps, is you need a compressor fridge if you want to run it on solar. With enough panels and batteries it will run 24 hours a day and not need any gas. A small one might only need 50W but you won't get a lot of change out of £500. Alternatively, buy a compressor cool box - but they are no cheaper I fear!
     
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  3. Yorick

    Yorick Funster

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    I have a 150w solar panel so that should be OK for during the day.
     
  4. Jaws

    Jaws Funster Life Member

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    Oddly enough, the way fridges work, the colder it is out side the more gas you will use as it will take more to heat the ammonia and water solution that is in a condensator fridge
     
  5. Yorick

    Yorick Funster

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    Aha, never thought of that :)
     
  6. John Laidler

    John Laidler Funster

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    As ambient temperatures increase an absorption refrigerator becomes much less efficient which is why above around 30°C you need fans to keep them working. This is because the temperature of the condenser fins will be around 40°C so as the ambient temperature approaches this the heat transfer which is needed to cool the hot gas inside slows down. Some industrial abosorbtion refrigerators spray water onto the condenser to cool it. Not sure this would be practical in a MH!
     
  7. Lenny HB

    Lenny HB Funster

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    A bit overoptimistic on the Solar depending on model a fridge can take up to 15 amps, you might stand a chance with 500 watts of panels only on bright sunny days of course.:D
    Have a look at the fridge spec the normally quote gas usage per 24 hours average running. I have noticed that the 8000 series fridge freezer in the current van uses a more gas that the 7000 series one in the last van & doesn't keep as cool, spec says the same for both models.
     
  8. Glandwr

    Glandwr Funster

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    My 3 way fridge freezer was eating gas. Eventually it stopped working on gas, called into an agent in Spain and they got out enough soot to cover a whole row of beans. Guess what, it then started freezing the food in the fridge. £16 new thermostat. Now actual cycling on and off now. It was previously burning gas 24/7 but not efficiently

    Might by worth checking, mine is 10 years old

    Dick
     
  9. trophychap

    trophychap Funster

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    @Yorick

    I know its not a manly thing to do but I read the instruction manual for our Dometic fridge and it actually tells you in hot weather to turn the temp down not up! I.E. if you for example have five bars put it on two rather than five if you follow me. It sounds backwards I know but it does work and also will use less gas, it might just be worth having your flue swept as well.
     
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  10. John Laidler

    John Laidler Funster

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    I suspect that is recognition in high ambient temperatures it can't achieve a low temperature internally, but it will consume a lot of gas running continually in trying to. When throttled back a bit (the thermostat set to a higher temperature) it will use less gas as it won't be running flat out all the time.
     
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  11. Yorick

    Yorick Funster

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    Aha, I'll try that :)
     
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