Solar heat exchanger
Posted by Solar energy guru | Filed under Solar thermal solutions
Solar water heating is a pretty old concept that people have been using for more than 80 years. However, with new technology we are able to accomplish this task much more efficiently. We use a solar thermal system to generate heat, and this is usually attached to some sort of fluid delivery system that in turn heats up the water. This is called a solar water heat exchanger, and it is an integral part of many solar water heating systems. Solar water heating can be applied to heating an entire house’s water system, or just to heat a specific body of water, like a swimming pool.
A solar water heat exchanger is, by itself, just a tank that can hold fluid. But that fluid tank has a few features that are essential to making the entire system work correctly. A heat exchanger is necessary when a thermal device transfers heat through a fluid – typically, some kind of anti-freeze like glycol or water. That liquid is capable of expanding under heat, which would place a lot of pressure on the entire piping system. The fluid is necessary because heat stored in gas dissipates too quickly. In order for the heat generated by solar energy to stay in your system, it needs to be transferred through a liquid.
Once the heat has been exerted onto a liquid, that liquid needs to go into a storage container in order to keep its heat from dissipating as well. The heat exchanger acts as a filter into that system. First, the heat exchanger prevents any glycol from entering the general water supply. It also measures the heat of the water to prevent it from getting too hot or cold. If the water is too hot, the heat exchanger closes off to prevent it from entering the house’s hot water supply until it cools off enough to be suitable for human use.
The second thing that the heat exchanger can do is regulate the output of your solar heater. The solar heater can generate a lot of heat, but in many cases, it can be turned on and off as to suit the need of the household. So when the water is too hot, the heat exchanger blocks it off from the rest of the hot water supply. In the same way, the exchanger can also turn the solar panel back on when the water gets to cold. The exchanger doesn’t just work with the solar energy, though, it works with whatever power source you have, so if you’ve split the power between solar energy and normal electricity, the exchange will still work exactly the same.
There are two basic categories of a solar water heat exchanger can be built: single wall and double wall. A single wall heat exchanger has one fluid inside it and another surrounding it on the outside. One fluid is entering your water’s system, and the other comes from your actual heater. The heat is transmitted through the metal of the heat exchanger, and this is how the two flows are kept separate. A double wall heat exchanger is just that: it has two “walls” of metal between the two fluids. This is safer, and keeps more metal between the two fluid supplies, but the additional wall means that the heat doesn’t transfer as easily, so you consume more energy using it.
Many solar water heating systems don’t have heat exchangers. Mostly, these are the newer models, which are made so that they don’t need any exchanger to achieve the function of transmitting heat. This essentially just saves time, money and supplies, as the lack of an exchanger means one less part of your water system that can suffer damage.