Solar Water Heating Systems

Solar Water Heating Systems

Solar water heating systems are a basically simple design. Solar collectors heat water during the day, which is stored in an insulated tank to keep it warm for ongoing use. But freezing temperatures can bring this kind of system to a standstill. But new and improved methods have been developed that allow solar hot water systems to operate effectively even in cold climates. Here is a basic description of how they work.

What kinds of solar water heating systems can be used In cold climates

After a few decades of experimentation with solar hot water systems, most experienced users have decide that the closed loop design is the most effective for climates with freezing temperatures. Because oxygen is eliminated from the system, pumps will not corrode and will have a longer lifespan, saving you time and money for repairs and replacement parts.

The system is filled with an antifreeze solution (propylene glycol) at the time it is installed. It then circulates between the solar collectors (where it is heated by the sun during the day) and the storage tanks, which provide heat during the day and night. There are several smaller components that allow the antifreeze to expand and contract, and which prevent too much pressure from building up in the system, among other things. But the solar collectors, the pump and the tank with heat exchanger are the basic components.

Drainback systems are so named because the solar collectors drain when they are not being used. For this reason, you can use either water or antifreeze in the system. But for maximum assurance that the system will not freeze, people often choose to use antifreeze as an extra precaution, especially in regions that frequently experience temperatures below zero.

Even though the collectors drain when not in use, they drainback system is still a closed loop system. It needs a powerful pump in order to return the drained liquid to the solar collector after it has been drained. But it is a good choice for a homeowner who wants a solar heating system that is easy to maintain.

How effective are solar water heating systems

Solar hot water heating systems are relatively simple to install, easy to maintain and the most cost effective way to introduce your home to solar energy. They can save considerable energy and cost when they replace an electric hot water heater. And they can be successfully used even if you live in a climate where freezing temperatures are common during the winter.

If you live in a climate that does not have freezing temperatures, and your household consists of fewer than five people, you can install a batch heater. This is the least expensive solar water heating option, and it is relatively easy to build if you have the inclination to do-it-yourself. It is simply a water storage tank that also serves as the solar collector.

The tank is enclosed in a glass-covered box that is positioned to allow maximum exposure to the sun. The water in the tank heats up and hot water is available for use. However, it is not the most efficient system, since it takes longer to heat an entire tank of water than to heat a flat panel solar collector. And as the tank cools at night, there is less hot water available for use.

There are two better systems that can be used even in freezing climates. The direct pump system circulates water between a solar collector and a storage tank. With this design, water in the solar collector can heat up faster, and the tank can be insulated for better temperature holding capacity. The pump can be designed to run on electricity from a photovoltaic cell if you want to keep your system completely solar powered.

A thermosiphon system also uses a separate solar collector, along with the pull of gravity. And it allows for the use of an insulated storage tank for more consistent hot water delivery. When using either of these systems in cold climates where freezing is an issue, both the piping and the storage tank should be located indoors and properly insulated to provide hot water even on the coldest days.

What kinds of hot water solar collectors can you build yourself

There are 3 main types of hot water solar collectors commonly used in homes: flat plate and evacuated tube systems. There are a number of different “recipes” for building each kind. But here is a quick description of their similarities and differences.

  • First, there are pool solar collectors. These are usually a type of flat plate design, but there are enough differences between solar pool heating systems and solar hot water heating systems that some explanation is necessary. 
    Pool solar collectors, are usually designed as rows of UV resistant black polypropylene pipe that is heat welded together. Because pool heaters require lower water temperatures than hot water for showers or for heating a house, the collectors do not need to be encased in a box. In fact, the polypropylene plastic is not intended to withstand the high temperatures needed for other domestic hot water use, and should not be enclosed by glass.
    Although solar pool heating systems are about the simplest solar energy system that you can build or install, the solar collectors themselves are not so easy to make. The polypropylene pipe does not respond to adhesives, and the process and equipment needed for heat welding is cost prohibitive for a do-it-yourself project. And using a substitute material may not be wise because of its tendency to break down with ongoing exposure to the sun and chlorine from the pool. For this reason, it is probably easier to buy the solar collectors even if you choose to install the system yourself.
  • Evacuated tube solar collectors are also tricky to build. Although they are used for domestic hot water and for heating a home with hot water, the materials require special handling. They use special glass tubing with double walls. The air trapped between the walls act as insulation, similar to the way dual pane windows trap air for insulation. The innermost tube can be filled either with water or with a heat transfer fluid to prevent freezing in cold climates. Obviously, this kind of system is more complex to build and install than a simple hot water heating system. Again, it might be easier to buy the solar collectors unless you have a lot of skill and confidence.
  • Flat plate solar collectors, also used for residential hot water and heating, are usually easier for a do-it-yourselfer to build. The design is fairly simple and straightforward. Flexible tubing for the water is attached to an absorber plate and positioned inside of an insulated metal box. A glass cover is used, which allows the sun to heat the water. As the water is heated, it is pumped into an insulated storage tank and held for use as needed for bathing or washing dishes. With the help of a good set of instructions, building and installing a hot water system using flat plate solar collectors is a good project for people who are handy and motivated.

Converting your main water heating system to solar energy is not a very difficult task

Solar water heating systems are widely available, easy to install and operate. It will adapt to your water taps without difficulty.Solar water heaters can be more costly to purchase and set up than traditional water heaters. However, by using a solar system to heat your water you will definitely save on your utility bills over time. Savings of 50% to 80% are realistic.

Quite a few ways for heating water using solar energy exist. Making your own solar water heater is also possible. What ever the solution you choose, you should keep in mind that you also need an electric or gas backup water heater for days when there is no sunshine. More info

A solar collector and a storage tank are the heart of the system. Both are located outside in order to receive maximum sunlight during the day
The operating system is straightforward, cold water runs through a circuitry of pipes built in a solar collector. When water inside the pipes becomes hot it flows into a storage tank. At this stage, hot water is ready to be distributed to the pipe network inside the house.
The most common type of solar collector for heating water is the glazed flat-plate collector. It looks like a rectangular flat box covered with a glass top. Inside this box resides a flat black plate called absorber. The role of the flat absorber is to transform the light coming from the sun to heat. Once the flat absorber is hot, water flowing through the tubes becomes hot. The hot water obtained is stored into a well insulated storage tank that will keep it warm and ready to use.

There are two types of solar water heating systems

Active and passive. Active solar heating relies on electrical and mechanical devices like pumps, to push the water inside the tubes and to the storage tank. On passive solar heating systems, the installation angle of the flat plate collector and the storage tank is critical because only gravity makes the water circulates from a side to another. As a result, the water flow can be slow sometimes. Both systems are efficient and at the end of the day, it is a matter of personal choice.
Solar water heating systems offer a simple and affordable solution. It can be set-up quickly and the technology is mature enough to make you decide to use it without any hesitation.. Heating water using solar energy is a clever choice for your pocket and for the environment.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>