Solar water heating systems have become more popular in recent years because of the rising cost of traditional energy sources and concern for the environment. Yet, solar water heating is nothing new. In ancient times, water was placed in urns or bowls in the sun to provide warm water for bathing. During the frontier days of America, water was placed in the sunshine in buckets to heat. Bath tubs in the frontier were often wooden troughs allowed to fill with rain water and heated by the sun during summer months. As early as the late 1800′s, commercial solar water heating systems have been available.
Today, solar water heating systems are mounted on a home’s roof and are quite non-obtrusive. A thin roof plate or several plates to collect the sun’s rays are seen on many homes, both new and old. The owners of these homes enjoy reduced energy bills every single month. They also know that they are using green energy and reducing their impact on the earth’s fragile environment by contributing much less to greenhouse effect and global warming trends.
For many families, solar water heating systems can provide all the hot water required. Location, design, how the solar collectors are positioned and the number and size of the collector boxes will affect the amount of hot water produced. Most families choose to retain traditional water heating capability to provide hot water in periods where the weather results in less hot water production from the solar water heating system.
What makes up a solar water heating system? Most solar water heating systems consist of a hot water storage tank, a solar collector box or boxes which absorb the sun’s rays and energy, and for active water heating systems a pump and controls are required.
Passive Solar Water Heating Systems
A passive water heating system powered by the sun is the simplest solar water heating system available. The water tank is often inside the solar collector box and is stored inside that tank. The water in the storage tank integrated into the solar collector heats and when hot water is turned on, water comes out of the storage tank and into the home. More cold water comes into the tank to fill the tank to capacity. This type of system is best used in mild climates. These systems are also used frequently for heating swimming pools which are only used during the summer in colder climates.
Active Solar Water Heating Systems
An active solar water heating system is the most common type used in the United States. It includes a pump which moves water from the cold water supply into the solar collector which is often made with small copper tubing, and when heated the pump moves the hot water into an indoor, well insulated storage tank for use on demand.
Solar Collector Types
The most common solar collector design used for hot water systems consists of a copper plate, painted black that has water tubes attached to it or placed just above it. As the sun’s rays fall on the plate, they are absorbed creating heat. The heat from the sun warms the water in the tubes that are above or connected to the copper plate. Once the water is heated in an active system, it is moved into the storage tank for use when needed.
Integral solar collectors combine the water heating function into the solar collector panel. This is the method used in most passive solar water heating systems. Some active water heating systems use this design as well, but this is not the most common collector type for home solar water heating systems. These are often used for swimming pool heating rather than for the entire water heating needs of the household.
An evacuated or vacuum tube solar collection system use a group of tubes filled with a liquid, often diluted antifreeze. Because the liquid medium is maintained in a vacuum, little of the absorbed solar heat is lost. The heated liquid is then used to heat water which passes through pipes heated by the evacuated liquid medium. These collectors are almost always roof-mounted and can be used for swimming pool heating, household water needs and even for home heating.
About the Author: Anita van Wyk strives to make make more people aware of the benefits of using solar energy through her website https://facts-about-solar-energy.com/