The Refrigerator

There is no appliance quite like the humble fridge for causing angst, argument and problems in your solar system. There is no race quite like us Australians with such a thirst for things cold ...

The problem with a fridge is this; a fridge is relentless, it goes day and night and cares not whether the sun is shining or whether it is raining. To exacerbate the problem, come winter when the days are short and the sun is low most fridges reside in a warm kitchen and power use can equal or exceed what is used in summer.

It is likely that your refrigerator will be your single biggest user of power ...

It is also likely that you will regard having a refrigerator as mandatory. I do. Let's look at your choices:

Gas: These devices are still available, work well and are often considered by folk living without power. The advantage is obvious! It needs no electricity to run. Simply hook up a gas bottle, light a flame and away you go.

The disadvantages are not quite so obvious but first and foremost is the cost of gas and the nuisance of having to keep the supply up, next is maintenance and finally if you think burning a flame to make things cold is efficient then you are slightly deluded. Forget gas unless kicking back in a shack up the scrub on the occasional weekend is your forte' and drinking cold stuff is more important than having lights and a telly. The reality is this; it is far cheaper in the long term to have an electric fridge running on solar panels than it is to run a fridge on gas. The only exception is a caravan, motor home, weekender or other place that requires only part time refrigeration.

Electric: The electric fridge is really your only choice and you can go two ways here, DC or AC.

The DC Fridge: For camping and where your requirements are small there are several excellent brands of small DC refrigerator on the market. The efficiency and reliability of these units is outstanding but the space inside them is limited and the smaller units are usually top loading which some may find inconvenient. These units will usually run on either 12 or 24 volts with automatic voltage detection. I am not aware of any that will run on 48 volts.

Another type of DC fridge is the converted AC type. The conversion is usually performed by a refrigeration mechanic using a brand new 'off the shelf" fridge from a major manufacturer. This conversion gives you a wider choice in available models and often allows the choice of something slightly larger than what is available pre made in the local DC fridge shop. The conversion results in much lower power use. The power savings come from the highly efficient but rather expensive DC refrigeration compressors on the market.

The AC Fridge: If you are like most of us, the AC fridge is the easiest to find, the most convenient and what you will choose. This is what I have chosen and you can slip on down to your local appliance store and get one too. It is however prudent to put a little thought into your refrigerator before actually parting with your cash. You want a fridge that will work well in a solar environment, will use the minimum amount of power from your solar system. My choice would be a 230 - 320 litre two door variety with a smallish freezer. If you want your inverter to turn off when the refrigerator is not working this may present an additional challenge. To accomplish this you will need a fridge with manual control and you will have to disconnect any auto defrost device if fitted. It would be a good ides to discuss this with a refrigeration mechanic before purchase!