Solar water heating is an underrated way of saving money. It’s not the easiest way to save, and it can take a while, but over a number of years, solar water heating can literally save thousands of dollars. One of the problems that prevent people from accessing more solar energy is that it is an expensive process with a slow payoff, but for those willing to wait, the savings can be incredible. Evacuated tube solar collectors are a method with which people can convert solar energy to heat, and use it to power an entire household’s water heating system.
Evacuated tube solar collectors are a type of solar thermal system – a system that converts sunlight to heat rather than electricity. Evacuated tubes are not the most popular method for heating water, but they can be far more effective than some more popular systems in the right environment. For example, flat-plate solar collectors are the most used solar water heaters, but an evacuated tube collector can produce far more heat and absorbs more light. However, this benefit is undercut by the fact that evacuated tubes are more expensive and complicated systems. They aren’t worth the additional expense in most situations, but in some situations, their benefits sharply outweigh their disadvantages.
Evacuated tubes produce a lot of heat compared to most home solar collectors. They absorb all of that heat from sunlight itself, and not the heat around the system. For that reason, they are much more valuable in cold environments. Because all of their heat is taken from light, they don’t lose any heat from being in the cold, and because they produce more heat, they work better when surrounded by colder temperatures. In a warm environment, like most that commonly have solar thermal collectors, they don’t present any real advantages, because their heat actually has to be limited for human use. But in cold environments, their additional power can be the difference between whether solar water heating is actually a viable solution or not.
Evacuated tube solar collectors are made up of a series of glass tubes that employ a vacuum system when contacted by light. This has the effect of keeping the heat contained within the system, which eliminates much of the heat loss that could occur in cold environments, which both keeps the water warmer and reduces the energy needed to create hot water. The heat within the glass tubes heats up the water or fluid contained within the system, which eventually runs through a heat exchanger of some sort, heating your water supply.
The heat produced by this system actually has to be limited to be used by humans, which is one reason why they are not advantageous in warmer environments – after all, why spend extra money for a more powerful system to do exactly the same thing. The exception for this is for people or companies who want to use this to boil and clean water. In warmer environments, this system produces enough energy to provide a consistent source of boiling water, so some commercial water vendors use it to clean their supply.
In essence, evacuated solar collectors are a very niche product. For most people interested in solar water heaters, a flat-plate system will work just fine and cost less to buy and install. For people in colder environments who have trouble heating their water enough, or who feel that they are paying too much in water heating bills, this can be an excellent option. As with most solar energy systems, it will pay for itself within a few years, the amount depending on how often and well it is used.
