DC Air Conditioning – Comfort on the water, no generator required

19 Responses

  1. steve says:

    This is not the best article on the Model Y heatpump. However this tech should trickle down to marine use soon. Methonal powered fuel cells, batteries and efficient motors will make the nearly green the near future for boats under 60 ft.


    • Thanks for sharing! There is no doubt that these guys are inventing tech that will eventually make its way to boats. High efficiency heat pumps are the future!

    • Alain Mabru says:

      Not sure what is he talking about, heat pumps, or DC heat pumps, or Dual coil Permanent magnet variable speed compressors, batteries are important without them the air conditioning is useless, but 12v ultra efficient heat pump compressors, PM fans, controls that monitor ever component to deliver the exact capacity need based on the load are also necessary.

  2. Joel says:

    Interesting, are any of the manufacturers working on a chilled water DC system? I would like to add a hydronic heater for year round living in cold places where reverse cycle won’t work.

    • Hi Joel, I haven’t seen any DC systems for chilled water. It’s not really necessary. Direct expansion split systems have much greater efficiency than constantly cooling/heating a water loop. One central condensing unit can be connected to a number of air handlers with refrigeration line sets. Termodinamica is doing this beautifully. Their VRV system can even support heating in water temperatures down to 23F. These systems are very custom, however, and exceed the budget of typical cruisers (like myself).

      Combustion based hydronic heating systems are still a great solution for smaller live aboard yachts up north. We love the Hurricane Heaters.

      • Joel says:

        Phil, thanks much for the reply, you have given me lots to think about.. I’m very interested in the 24v system. I have several questions (I’m looking at complete refit of the air conditioning of my 55foot trawler). Would you recommend I call the Florida office or Boston, my boat is on the Chesapeake.

  3. Grant Jenkins says:

    Phil -good article, and pretty impressive system. Your install also appears nicely done. I’m curious which device you’re using for 12-24VDC conversion, as pictured in the article, and is it fully programmable to deliver the correct charging profile for those battle born batteries? Thanks,

    • Thanks Grant!

      At the moment, we are using the buck-boost 100A converter from Victron Energy. Although we are working with a manufacturer to develop a new DC converter that will be specialized for this application.

      The Victron buck-boost is programmable with software on a PC. We’ve spent a lot of time getting the parameters right. Not just to charge the BB batts properly, but also to protect the 12v house bank.

      • octafish octafish says:

        Hi Phil,

        I have 2 Verado 225hp with the 70amp alternators (x2).

        I connected (1) 30amp victron dc/dc orion + (1) 18 amp victron orion and I’m getting between 35-40amps from each engine into my 600ah lithium bank.

        Voltage read on my smartcraft gauge seems to be steady at 14.2v (as long as I’m running).

        Any other insight you could spare regarding charging from outboards?

  4. JAMES HAUGHEY says:

    Hi Phil, just wondering, how loud are the chillers? I have the webasto dual compressors on 220 v. for comparison.

  5. Carl Nelson says:

    Do you have any experience with the small Frigomar inverter 110v units? The watts look only a little worse than the Termodinamica. As I have a Victron multi a super efficient 110v A/C seems a better idea than 24v. http://www.frigomar.com/en/products/self-contained-unit-inverter-bldc/

    • Hi Carl,

      Yes, the Frigomar units are great and it’s totally reasonable to run them on an inverter. For larger boats, which still desire climate control without the generator running, we often design an inverter based system. That said, at full power, Frigomar units still use quite a bit more watts/btu than some of these other systems. However, they are variable speed and adapt to the heat load by slowing down the compressor and reducing current draw considerably when the boat is down to temp.


  6. Brent Snyder says:

    How can i buy one of these systems ?

  7. Shannon says:

    The dc aircon sounds great how much is a unit to do the cab of a 28ft bayliner

  8. Great article! Whether a large or a small AC unit for boats or enclosures, they make spaces efficiently cool, providing efficient trips despite fluctuating temperatures or heat levels.

  9. Steve says:

    Looking to supplement or replace y Donetic AC on my 2022 Southport 33 DC.

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