Firstly, the Gas fridge uses about 330gms of Gas/24hr period.
They don't work on much of an angle. Efficiency decreases from only a few degrees from verticle and about 30degrees is absolute max. However, unless you are heeled over for a very long time, this has never been an issue yet for us. It maintains it's Coldness for a substantial time.
The issue of Gas is not a problem, as long as you follow some important points. Ensure you purchase
a fridge that has a Gas shut of system due to Flame out. Some Gas appliances
can even have CO2 sensors, but I have no idea if any Gas fridge makers use such.
You MUST ensure you have an exhaust
vent OUTSIDE the boat. You do not want the exhaust
venting into a confined space. Although we do not use an exhaust, the space it vents into is large and is not closed off. So a fresh air cycle is always maintained. The second point to that, is that the hot air MUST have a place to escape so as fresh air is drawn into the flame area to keep it going.
The next very important point is to have good ventilation around the heat exchanger
. This is the most difficult point to achieve on most boats. We have a vent at the bottom and at the top so as air circulates and cold air is drawn up from the bildge. The colder the air is, the more efficient the fridge becomes. In the heat of summer, we found the fridge was not getting cold enough. I fitted a temporary fan to the back to circulate air, and the unit worked perfectly again.
The two and threeway versions have electric
elements to create the heat. This is where I believe the entire system falls over for a boat. DC will draw approx 17A @ 12V. That's all the time. The elements do not cycle with the fridge thermostat. And that's the other down point for both DC and AC. The elements are on 24/7 while you have the system switched on. These elements eventually fail. We have had our going 24/7 for two years now, and I now notice a big difference in heat from the aging AC element compared to the other two means of heating
As an example of what these can do, I placed a four ltr container of Seawater in the ice box and it was frozen solid in a couple of hrs. It takes a bit to feeze Saltwater.
I also have two other units. One is a 230V only Freezer
. It runs fromt he inverter
and has been the best buy of all our cooling equipment
. It was just a standard small lightweight freezer
that way cheap
. And it works just fine and is very light on current
draw. The other is a fridge box with a Waeco refer unit that uses the Danfoss 12V compresor system and the fan/cooling unit in the cooling
box. It doesn't have all that much grunt. I expected a little better. Especially as it draws the same current
as the 230V Freezer.
Hope that helps.