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Solar + Fridge + No Battery ?

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  • Solar + Fridge + No Battery ?

    Is it possible to run a "direct drive" refrigerator using only PV Panels, without any battery?

    Direct Drive Fridge SunDazer BFRV55 ...
    https://sunshineworks.com/pages/vacc...-refrigerators

    This technology is great for sunny locations with no battery banks.

    Twin "East & West" 60 Degree Array ...
    http://bucket.sunshineworks.com/down...lar-sizing.pdf
    Last edited by NEOH; 10-12-2017, 04:03 PM.

  • #2
    I would expect them to use a DC supply variable drive motor to maximize efficiency. Bruce Roe

    Comment


    • #3
      Direct Drive and thick insulation = Ultra High Efficiency

      An amazing 83 Hours = 3.5 DAYS of autonomy, at 110 F ambient.
      On cloudy days, don't have to run the genny for the fridge.

      500 WHr consumption per day.

      They claim ...

      Requires only 2 @ East-West PV Panels ...
      a) 150 Watt PV Panel facing 60 degrees East ( approx extra +1.5 hour morning run-time )
      b) 150 Watt PV Panel facing 60 degrees West ( approx extra +1.5 hour evening run-time )
      at 35C / 95F Ambient

      Comment


      • #4
        Looks pretty advanced refrigerator. I wonder what it costs to perform like that only using DC generated directly from pv panels?

        Also it states 490 watt hours per 24 hour period. Why do they provide that information if usable sunlight is at best maybe 12 hours a day using that East West orientation. My guess is that they use batteries when the sun isn't shining.

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        • #5
          Nope, no batteries needed
          No AC Inverter needed.
          PV Panels only - that is the selling feature.
          The fridge consumes 0 Watts from sunset until to sunrise,

          490 WHr per day - easy for me to compare to a normal fridge consuming +/-1,000 WHr per day and usually needs a battery bank at night.

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          • #6
            Not only thick insulated walls, but any refrigeration unit like this should only be a Chest type. Even if you do not plan to open the door after Solar power production, there will be loss around the bottom of the seal. Keeping an amount of frozen water in the unit can help maintain temperature. Either way I would not attempt this project with an inverter involved, this, If it can work at all, would only be accomplished with a Native 24 volt refrigeration unit. I can see using a small 24v battery bank with high LVD setting to cut the compressor after sun goes down. Batteries would only be used to stabilize your DC voltage and protect your compressor. If you plan to do this with a Front load refrigeration unit using an inverter, will not likely work w/o huge battery and over size inverter.

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            • #7
              Originally posted by NEOH View Post
              Nope, no batteries needed
              No AC Inverter needed.
              PV Panels only - that is the selling feature.
              The fridge consumes 0 Watts from sunset until to sunrise,

              490 WHr per day - easy for me to compare to a normal fridge consuming +/-1,000 WHr per day and usually needs a battery bank at night.
              Ok. It does sound very nice but what is the cost for that frig?

              Comment


              • #8
                Originally posted by Logan5 View Post
                Not only thick insulated walls, but any refrigeration unit like this should only be a Chest type. Even if you do not plan to open the door after Solar power production, there will be loss around the bottom of the seal. Keeping an amount of frozen water in the unit can help maintain temperature. Either way I would not attempt this project with an inverter involved, this, If it can work at all, would only be accomplished with a Native 24 volt refrigeration unit. I can see using a small 24v battery bank with high LVD setting to cut the compressor after sun goes down. Batteries would only be used to stabilize your DC voltage and protect your compressor. If you plan to do this with a Front load refrigeration unit using an inverter, will not likely work w/o huge battery and over size inverter.
                Nope, don't need frozen water with his chest fridge (waste of precious space)
                Nope, don't need any batteries
                Nope, don't an LVD to protect the compressor - WHO told you it needs that?
                Nope, don't need an inverter
                ( you can discuss your "battery based" ideas in an alternate thread )

                You are unnecessarily making a very simple idea ( PV + DC Chest Fridge ) into an overly complicated Rube Goldeberg machine
                Can't you see the beauty in the simplicity of this design?
                Last edited by NEOH; 10-12-2017, 09:27 PM.

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                • #9
                  It isn't cheap... $3400 here. I'm not sure how that stacks up for 55L of storage to other options.

                  Some reviews... it seems to work as advertised when transported and set up properly.

                  It looks like a nice design, though.
                  CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

                  Comment


                  • #10
                    Originally posted by NEOH View Post
                    Requires only 2 @ East-West PV Panels ...
                    a) 150 Watt PV Panel facing 60 degrees East ( approx extra +1.5 hour morning run-time )
                    b) 150 Watt PV Panel facing 60 degrees West ( approx extra +1.5 hour evening run-time )
                    Not that it is very important, but the wording made me check. Their diagram is for one panel facing East (90 degrees) and another facing West (270 degrees) both tilted 60 degrees.

                    The reason that they can give one tilt number for all locations is that they are interested in catching the sun at a very low elevation and not at all interested in maximizing anything but length of day. Obviously there is no reason to not swing them a bit more southerly in the winter at higher latitudes.

                    Comment


                    • #11
                      Originally posted by sensij View Post
                      It isn't cheap... $3400 here. I'm not sure how that stacks up for 55L of storage to other options.

                      Some reviews... it seems to work as advertised when transported and set up properly.

                      It looks like a nice design, though.
                      It is a nice design and I am impressed. But unless I had organs that needed to be kept cold I would be spending that $3400 a lot differently and still have cold beer for months.

                      Comment


                      • #12
                        Originally posted by sensij View Post
                        It isn't cheap... $3400 here. I'm not sure how that stacks up for 55L of storage to other options.

                        Some reviews... it seems to work as advertised when transported and set up properly.

                        It looks like a nice design, though.
                        Thank You for finding the price = $3,400
                        https://sundanzer.com/product/bfrv55/

                        Wow, that is way more than I expected.
                        Solar Panels have significantly dropped in price.
                        Lithium Cells have in significantly dropped in price.
                        New ideas are always expensive for early adopters.
                        Some day ... a DC Direct Drive Fridge will be affordable.
                        Maybe when demand is high enough and another vendor manufacturers then competition could lower the price?

                        If the fridge was $750 and then add two Solar Panels - now that would be a deal.

                        In the spec, it states: Requires: 3,500 WHr/m^2 per day

                        Then is this true ... approx 4.4 Hours of sun required per day = 3,500 / 800 ?

                        Comment


                        • #13
                          Originally posted by AzRoute66 View Post
                          Not that it is very important, but the wording made me check. Their diagram is for one panel facing East (90 degrees) and another facing West (270 degrees) both tilted 60 degrees.

                          The reason that they can give one tilt number for all locations is that they are interested in catching the sun at a very low elevation and not at all interested in maximizing anything but length of day. Obviously there is no reason to not swing them a bit more southerly in the winter at higher latitudes.
                          You are correct
                          They suggest that the two Solar Panels point in roughly opposite directions ...
                          Panel #1 points towards the East with a 60 degree tilt
                          Panel #2 points towards the West with a 60 degree tilt
                          ( agreed - adjust compass points as needed for your latitude and season )

                          60 Degrees was selected because at Solar Noon each panel with be at ~50% Power [ cosine(60 degrees) = 0.5 ]
                          This creates a lower peak power but a much wider and very flat power band.

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