What is a Heat Exchanger in Solar Water Heaters?

venturist | Mar 31, 2010 |

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Any solar water heater system uses heat exchangers so that solar energy can be transfered and absorbed, only to be used in order to heat water or heat space. A heat exchanger can be created out of bronze, steel, copper, stainless steel, cast iron or aluminum. We see copper being usually used because it is one good thermal conductor while also being highly resistant to corrosion. Let us analyze some common heat exchanger types that you might want to utilize.

There are basically two types of heat exchangers: liquid to liquid and air to liquid. A liquid to liquid solar water heater heat exchanger will use heat-transfer fluid. Solar collectors will be circulated with it. After that heat is absorbed and taken with the help of heat exchangers so that it can reach water in storage tanks. A number of heat transfer fluids will protect the collectors from freezing. Such a liquid to liquid heat exchanger system will use 1 or 2 barriers in order to be properly effective.

Any heat exchanger constructed through a system based on 1 wall will have a tube or a pipe that is always surrounded by fluid. A double wall exchanger will have 2 fluids and walls between them. In most cases a double wall solar water system will be required as the safety provided is higher. Unfortunately we can not find a lot of efficiency in them if there is a comparison to single systems.

Air heater collectors are included in air to liquid systems. Between the solar collectors and the air distribution systems there will be no need of using heat exchangers. The two exchanger systems stand out as being highly similar besides the fact that one uses air and the other liquid.

Sizing is always important whenever you are building solar water heat exchanging systems. If you want everything to be effective size is really important. When you analyze the subject you have to look at heat transfer fluid, temperatures in inlet and outlet, flow rates and the type of heat exchanger that you use. In most cases manufacturers are to give ratings for heat exchangers supplied. Read all the specifications in order to make the best possible decisions.