Set up For a Solar Powered peltier Refrigerator , Load issues, and Connections

[charlie12419]

Hello everyone newbie here
We made a project study venturing a peltier based Refrigerator having a power source of a solar energy . Upon the experiments. We aim to have 12 V 23 amps fot optimum performance for all of the DC components (4 fans, 1 pump, 4 peltiers ; all parallel connection) of the said Prototype.  Should I connect directly the Loads on An Mppt controller? Will it be able to
Provide 23 amp requirements .

Im searching a lot of resources but most of the set ups have inverters with AC appliances
But our prototype here is in dc

By the way we planned to buy 400 watts solar panel to reach an amount of atleast 22 amp, 30 amp mppt controller, and a
12 v 100 AH battery just to run it for short hours since the refrigerator proposed will run only on daytime ,

( peltiers are dependent on wattage provided on them so they can still do the job but decreased performance so we aims to have atleast 20 amps to make sure it cools inside.

 

[BentleyJ]

Using thermoelectric devices for a refrigerator is very inefficient, in fact I can't think of another way that would waste more energy. Maybe if the heat was recovered to heat water or something like that it would make more sense. 12V x 23A = 276W.

A mini fridge or undercounter model that runs on AC would only use 70W to 100W. That would require an inverter large enough to start the compressor but still would be more efficient than the proposed Peltier method.

 

[charlie12419]

Thankyou for Your Response . Im aware of the COP difference of the Mini fridge compared to Thermo electric based refrigerator. It just that our project was proposed and were instructed to improve more on its effeciency in terms of cooling intervals and Cooling capacity.

We have designed the refrigerator to reach an optimum refrigerating temp in 1 hr consuming 270 watts ...

Yes, it consumes a lot of Energy that's why we planned to use renewable energy as source of Power . Were just struggling for the solar set up to maintain 12 v 23 amp. Can you help me?

 

[BentleyJ]

The most basic set up would be what you described above.
1) Solar panels sized based on Azimuth, Tilt, average solar conditions. Are the panels fixed or are they portable so can be set in the most favorable position? There are online calculators that can help determine how many kWh are expected from solar panels under various conditions and geographic locations.
2) Battery sized to provide sufficient Amp hours for required evening and night run time. Lead acid batteries have about 50% usable capacity while Li types can be discharged 80 to 90% of capacity.
3) Charge controller of sufficient capacity and open circuit voltage tolerance for the PV panel(s) chosen based on considerations listed above.

A 400W PV panel is rated at Standard Test Conditions but under normal operating conditions and temperatures will produce less. This has to be factored in when choosing how many panels. For example, at least 2 x 400W panels would be needed in order to produce a peak output of 600 to 650W and this would only be at the prime periods of the day between 11 am and 2 pm.

Without further design specifications its not possible to provide more specific recommendations.