Question: The refrigeration system on my boat seems to consume quite a bit of electrical power. This can be a problem because it tends to run down the batteries. Is there anything I can do to upgrade my system to reduce this power consumption, short of buying a whole new refrigerator?

Isotherm smart energy control

The Isotherm Smart Energy Control reduces the electrical consumption of marine refrigeration systems that use Danfoss compressors.


Answer: Funny you should ask. I was recently at the IBEX show, an annual industry event that showcases what’s new and exciting for use on boats. It just so happens that this year, the folks at Indel/Webasto, producers of Isotherm refrigeration systems, had a new product entry that really got my attention and could be the answer to your problem. The Isotherm Smart Energy Control system is a real breakthrough, and won an innovation award this year in the electrical system category.  The micro-processor controlled system can be retrofitted to just about any refrigeration system that utilises what is known as a Danfoss compressor. These compressors are used on about 60 per cent of existing systems out in the marketplace today, so it’s not exclusive to Isotherm products. Your existing system may very well use this type of compressor; you’ll need to check that with your refrigerator manufacturer.

The new control system works by more accurately sensing and monitoring two key elements - temperature in the lower section of the refrigerator, and onboard system voltage. Exact parameters can be calibrated via a set of dip switches in the control module (the blue box in the photo). The Danfoss compressor is a three-speed unit, and in a nutshell, the system controller saves energy by adjusting the compressor speed based on the temperature and the voltage available to actually run the compressor motor.

So, what’s the bottom line here? According to the representative from Isotherm that I interviewed, this new control system promises a 30-50 per cent reduction in onboard DC power consumption for the refrigeration system. That’s significant, and in my view certainly worthy of the IBEX Innovation award this product received. Check it out at the link above.

- Ed Sherman