Could we make a practical solar fridge?

Thread starter anorlunda
Start date Sep 9, 2022
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fridge Practical Solar

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SUMMARY

The forum discussion centers on the feasibility of creating a solar-powered refrigerator designed for off-grid living. The proposed design utilizes a chest freezer divided into two compartments, with a variable speed BLDC compressor powered directly by a solar panel. The system aims to store energy in the form of frozen water, ensuring food preservation for up to three days without solar input. Key components include a microcontroller for motor speed regulation and a focus on maintaining efficiency through innovative thermal mass solutions.

PREREQUISITES

Understanding of BLDC (Brushless DC) motors and their applications
Knowledge of thermal mass and phase change materials in refrigeration
Familiarity with solar panel systems and energy storage concepts
Basic principles of refrigeration and compressor operation

NEXT STEPS

Research the design and implementation of variable speed BLDC compressors
Explore the use of phase change materials for thermal energy storage
Investigate solar panel sizing and energy output calculations for refrigeration systems
Learn about the process of retrofitting traditional compressors with DC motors

USEFUL FOR

This discussion is beneficial for DIY enthusiasts, renewable energy advocates, and engineers interested in off-grid refrigeration solutions. It provides insights into practical applications of solar energy in everyday appliances.

Oct 2, 2022

sophiecentaur

Science Advisor

Homework Helper

The Bill said:

Another option is to use a nonimaging solar heat collector (maybe something similar to the evacuated glass tube collectors on solar water heaters) to power an absorption refrigerator.

I think that could be a good way to go. Absorption fridges were popular for camping because they could use gas, 12V or mains, depending on the circumstances.

But what about using a totally thermoelectric (Seebec / Peltier) system, with a solar furnace beamed onto a large area of Peltier panels (pretty cheap and modular) and some thick cable, routed round the house, to similar panels in the fridge?

The temperature of the hot source should be as high as possible, consistent with the panel not getting over-cooked (<320C or less for cheap units). That could be taken care of with a bimetal strip to defocus or deflect the incident sunlight. Efficiency could be a problem but hot weather would supply more cooling than cold - which is the right way round.

Any system with interrupted power supply could use water / ice as a thermal store but, in a static situation, a water tank wouldn't be a problem.