Refrigeration Controls

Having installed refrigeration, now that we have solar panels, I started thinking about a better way to control the refrigeration.

The refrigeration unit I installed came with a basic mechanical thermostat. After freezing the vegetables then melting ice in the freezer while learning how to set the thermostat I decided there must be a better way.

In addition although we have a lot of energy from our panels, there are days that are cloudy and rainy and the refrigerator runs at night when solar power is not available.

I work from the boat and write this blog which is also a drain on power resources when there is no solar energy, so efficient use of power especially at night is a priority.

As refrigeration is the largest use of electricity, its the place to start when looking to conserve energy.

Most refrigeration systems use the Danfoss BD35F, BD50 or BD80 which all include an electronic compressor control which allows the compressor speed to be set by inserting a resistor in the thermostat circuit. Danfoss also offer an expensive AEO compressor controller which saves energy by optimizing the compressor speed. The slower the compressor speed the more efficient the cooling even if it takes longer to reach the set point.

I looked around and could not find an electronic thermostat (so that I could control and display temperature) that would also minimize energy consumption when excess energy is unavailable and quickly cool when excess energy is available. And all at a reasonable price.

Having worked in control of refrigeration for energy savings since 2003, I decided to develop a controller based on components I have used and my experience as a controls/electronics engineer. The result is CoolSaver.


Its a digital thermostat/thermometer that minimizes energy consumption when running from the batteries and maximizes cooling and cooling storage when there is excess power. Similar to the “coasting” principle used by cold plates.

Rather than describe it here, check out which is the official CoolSaver  website. CoolSaver is available in 3 versions.

  • A thermostat/thermometer that uses energy save technology.
  • A thermostat/thermometer without energy save technology, but with the ability to switch to an energy saving temperature and compressor speed manually via dedicated buttons on the front panel.
  • A Digital Thermostat  (for those who want an excellent thermostat and have all the energy they need)

These products are available at and at installers / distributors.

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