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In this day and age there is no need to have a wasteful and expensive electric or a gas water heater.
For the past 40 years the development of environmentally responsible technology has been very slow. Unfortunately it was branded "Alternative Technology", a name which tended to suggest a novelty to be humoured rather than technology to be taken seriously. In Britain at a time when millions were being spent each year on developing nuclear power the total annual budget for environmentally responsible technology was about threepence halfpenny and a couple of marbles.
Years ago I visited the "Alternative Technology Centre" in Wales an exciting place that displayed and researched a broad range of the latest energy efficient technology that was available at the time such as windmills, Pelton wheels (high tech water wheels), solar heaters, ram pumps, high efficiency insulation, double glazing, photo voltaic cells, solar heaters and hand operated tooth brushes. Hidden away in the Welsh mountains the centre was out of sight and out of mind for most people.
It was a dangerous place to go in those days, in a world that didn't trust anyone who didn't conform to the natural laws of bigotry you could be easily branded as one of those tie dye hippy types or, even worse, a morris dancer! Mind you I have always been a bit of a rebel, I once walked into a shop in Western New South Wales and dared to ask for a loaf of brown bread. The bloke sneered at me and said ".... you one of them there health freaks or something?" I escaped by the skin of my teeth that time.
Finally the world is now waking up and things are changing, you can now buy brown bread in New South Wales, the name "Alternative" has been dropped and windmills are springing up across the world. Finally we are seeing some real effort being put into developing what we should be calling "Essential Technology".
We have to realise, however, that there is one inescapable fact - if new technology is to succeed it has to be widely accepted and to do that it must be practical, convenient and affordable. "Affordable" is particularly important and the low cost of traditional "dirty" energy sources has been a stumbling block making environmentally responsible energy sources unable to compete financially.
Certainly the disappointingly low uptake of solar energy is a case in point and can be directly attributed to the high cost of solar collector systems (for both hot water and electricity generation). Several studies carried out in Australia years ago came up with the same result. A solar hot water system would pay for itself in 7 years but the tank would rust out in 8. Of course no one would ever suggest that solar heater manufacturers, fearful of an impoverished future rummaging through rubbish bins, were purposely following a policy of built in obsolescence.
Perhaps we should look at solar water heaters in more detail another time.
But now there is a sensible, practical and, most importantly, low cost way that most of us can heat our water.
Known as the (click here Air Conditioner Water Heater) it is a simple device that takes the heat that is normally thrown away by an air conditioner and uses it to heat water. The heater consists of an insulated water tank very similar to a standard electric water heater. Instead of a heating element the tank has a heating coil from the air conditioning system which heats the water.
Only two hours of running time of your air conditioner will heat a 100 litre tank of water to 65 degrees centigrade. Is this hot enough? Well most solar heaters work on a maximum of 60 degrees, any hotter than this is considered dangerous should an unsuspecting child turn on a hot tap.
Unlike a solar hot water heater these heaters can work both night and day. They are considerably cheaper than solar water heaters and in fact cost very little more than a standard electric water heater.
Once installed they require no energy to operate. The hot water is free. These units are available with an electric heating element should you think you might need electric heating as a back up.
So how do they work?
Let us start by looking at a standard split air conditioner. An air conditioner is a heat pump, it removes heat from your house. It has a heat exchanger in a unit mounted on an internal wall of your house which collects heat. It has another heat exchanger which disposes of this heat outside your house.
The key to the system is the rather clever refrigerant stuff (we often wrongly call it freon, Freon is in fact the DuPont trade name for CFC based refrigerants that are ozone depleting and banned). So what is this refrigerant stuff, is it a gas? Like other gases if you compress or remove heat from a refrigerant it will turn into a liquid.
Or is it a liquid? Like other liquids if you heat it it will boil and change into a gas by absorbing the heat.
Refrigerants are special in that they boil well below room temperature.
So in our air conditioner we have a length of pipe containing refrigerant gas. In our outdoor unit the gas is compressed to turn it into a liquid. As it changes to liquid (it unboils so to speak) it gives off heat which a fan blows away. The refrigerant liquid now moves around the system to our wall mounted indoor unit, here the pressure is released and the liquid boils evaporating back into a gas and absorbing a lot of heat from the room. A fan draws air from the room and blows it over the heat exchanger pipe so the evaporation of the refrigerant removes the heat from it. The refrigerant, now a gas, returns to the compressor unit to be compressed into a liquid again.
In the Air Conditioner Water Heater the pipe in which the gas is compressed goes through the water heater before it goes through the outdoor heat exchanger. The heat given off as the gas is compressed directly heats the water. The heat is literally pumped out of the refrigerant into the water.
This is far more efficient than a standard electric water heater in which an electric heating element converts electrical energy to produce heat. An air conditioner is a heat pump, it doesn't produce heat, it moves heat. This is why an air conditioner typically uses only a quarter of a kilowatthour of electrical power to produce a full kilowatthour of cooling in your house and, with the addition of an air conditioner water heater, a full kilowatthour of heating for your water at the same time.
Air Conditioner Water Heaters are sound technology, they are very simple, low cost and highly effective.
There is another significant advantage here in Bali. Our electrical supplies are often very unreliable and many of us suffer electrical drop outs due to power surges as high demand items such as water pumps and heaters switch on and off. An air conditioner water heater removes the high electrical consumption of an electric water heater from our systems and so can reduce our electrical problems.
...and the bottom line:
A standard electric water heater takes about 4.2 kilowatthours of electricity to heat a 100 litre tank of water from 24 degrees centigrade to 60 degrees centigrade. A kilowatthour of electricity currently costs 1,340 Rupiah.
If you use a tank of hot water every day this will cost you about 2 million rupiah a year. This means the air conditioner water heater will pay for itself in about 2.5 to 3 years - a considerably faster pay back than a solar hot water system which may take 6 to 12 years to pay for itself depending on the model you buy.
If you are, like me, a person who has learned to live in this wonderful climate without air conditioning obviously you will have to go solar.
For you frosty types that have air conditioners running there are two brands of air conditioner water heaters available in Bali, Wika and Rifan, and domestic systems come in 75 litre (one bathroom) and 100 litre (two bathroom) sizes.
These days this is safe technology, the dangerous days are gone when "Alternative" people dressed in anoraks and balaclavas held secret meetings in the back rooms of dingy pubs and whispered phrases like "The one armed striptease artist likes hers sunny side up" which of course means "I would like to buy a solar panel."
Phil Wilson
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