Everything you need to know about solar water heating systems for your home or commercial use
The use of solar energy for heating water is gaining momentum steadily around the world, thanks to numerous advantages solar energy has on offer. It is not only economical and has the potential to cut down on your monthly power bills, but offers an exquisite range of eco-friendly features, too.
Solar water heaters, also known as domestic hot water systems, is an eco-lavish and cost-efficient way to generate hot water for your everyday residential applications. The fuel they use, i.e. sun energy, is abundant and freely available, and therefore water heaters can be effectively put to use in almost any type of climate.
How They Work
A solar water heating unit includes solar collectors that are generally mounted on your rooftop in an array, and storage tanks. Solar water heating systems are generally of two types,
· Active: which include water circulating pumps and controls
· Passive: which work without a pump or control
1. Active Solar Water Heating Systems
Active solar water heating systems can be further classified under two categories:
· Direct circulation systems
In direct circulation heating units, pumps are used to circulate water through heat collectors and then through your home at points where hot water is required. They come handy and work with high efficiency in climates where it barely freezes.
· Indirect circulation systems
In indirect circulation type water heating units, pumps are used to circulate a heat-transfer, non-freezing fluid through a heat exchanger and the collectors. Heat absorbed by the collectors from solar energy is passed on to the circulating fluid which, in turn, transfer the heat to the water required to be heated. These types of solar units are more fancied in areas where freezing temperatures are common.
2. Passive Solar Water Heating Systems
Passive solar water heating is a cost-efficient, dependable and easy-to-use method to harness the solar energy of the sun for addressing energy requirements at your home or commercial property.
Passive solar water heating supplies around 90 percent of domestic hot water requirements each year. With about one0third of mean power bills accounting to heating water, a solar water heater system is surely a smart choice to make for the environment and your home. Power saving generally pays back for the installation cost of the system in close to 5 years.
While the installation cost of passive water heaters may well be on the higher side, they are more efficient and long-lasting. Passive water heaters come in two different variants:
Integral collector-storage passive systems
These arrangements deliver striking results in climate where it hardly freezes. They are also efficient in residential establishments with considerable daytime where evening hot water is a major necessity.
· Thermosyphon systems
In Thermosyphon systems, water is circulated through the heating system when the warm rises due to sinking of the cooler water. These systems are heavily dependable, however, it is utterly important for the contractors to be vigilant regarding the roof design since the water storage tanks are bulky and heavyweight.
Cold water flows through the pipe towards the batch collector or a solar backup/storage water tank, depending upon which inlet value is open.
Storage tanks and solar collectors
Most water heaters need an insulated hot water storage tank. In addition, solar storage tanks have inlet and outlet linked to the water collector. In a basic two-tank arrangement, the water heater is used to pre-heat the water before it flows into the traditional water tank. On the other hand, the solar back-up water heater is linked to the solar storage in the tank.
· Solar collectors are conventionally of two types:
Flat plate collectors are weatherproofed and insulted boxes containing a dark absorber plate beneath one or more plastic or glass polymer covers. Unglazed collectors, which are generally used for solar heating of pool water, have dark absorber plates made of polymer or metal, with no enclosure or cover casing.
Integral collector-storage systems
Particularly known as ICS or batch systems, these type of collectors flaunt one or more black tube or tank in a glazed, insulated box. Cold water first flows into the collector that provides preheating to the water. The water then flows into the traditional back-up heater, offering a dependable hot water source. These systems must generally be installed in climates with mid-freeze conditions since the external pipes can get frozen due to extremely cold and chilly conditions.
Selecting a Solar Water Heater
The market today has a landslide of water heaters, based on different mechanism and line of action. Since an ideal water heater can help you go green and cut down massive on your monthly power bills, it is important that you work upon the following points before choosing one for your industrial or residential purposes:
· Estimate the energy efficiency and cost of the water heating unit
· Understand the correct system size
· Evaluate the solar resource at your location
· Investigate regulations, covenants and local codes, covenants, and regulations.
Also, it is important for you to understand the requirement and application of different mountings and accessories a water heating unit requires, and how to choose them to ensure you get the best combination of performance and cost efficiency:
· Heat exchangers for the systems
· Heat-transfer fluids for water heating
· Installation and maintenance of the system
The appropriate installation of water heaters relies on numerous factors. These factors comprise of local building code requirements, safety issues, solar resource, climate, etc. and, therefore, it is utterly important to get an expert recommendation from one of your nearest hot water system manufacturer to ensure you get more life, performance and cost-efficiency from your hot water system.