There are two types of solar water heating systems :

a) Forced Flow / Pressurized, which have circulating pumps and controls and Solar storage tanks have an additional outlet and inlet connected to and from the collector.

b) Thermosyphon Systems, In this type water flows through the system and when water gets warm it rises as cooler water sinks. The collector is installed below the storage tank so that warm water will rise into the tank. These systems do not involve any pump and are more reliable.

Solar Water Heaters have several advantages over conventional water heating systems as they:

• Reduce electricity bills: 40% of an average household's energy bill comes from water heating.
• Save interior space: These systems are usually located on rooftops.
• Increase safety: Solar water heaters eliminate the risk of accidents in bathrooms due to electric water heating equipment.
• Hot water all year round: BoroSolar heaters come with an optional electric backup for very cloudy days .
• Quick payback: On average, a good quality solar water heater will have a payback period of 1½ - 2 years in Indian conditions.
• Protect the environment: In today?s environment conscious world, you can make a difference by getting your hot water free from the sun. By replacing an electric water heater with a solar water heater, you can reduce greenhouse gas emissions by up to 3 and 4 tonnes a year ? the equivalent of taking a small car off the road.

Unique Characteristics of Borosil systems :

As previously mentioned, the evacuated tube is the most important component of the solar water heating system.

Currently, all ETC systems in the market are being sold with tubes imported from China. Since the quality of these tubes is inconsistent, the water temperature reached often varies, leading to higher breakages during transit and even after installation. Borosil tubes are made from an ISO 9001:2000 facility and are subject to 100% inspection. The evacuated tubes have to be made from low expansion borosilicate glass. Borosil is the only manufacturer of borosilicate glass in India, and its high quality products are used in laboratories worldwide. The two unique properties of this glass are:

• Resistance to thermal shock: Borosil?s 3.3 expansion borosilicate glass can withstand temperature differentials of up to 180°C, as well as repeated heating and cooling without cracking.
• Resistance to impact: Borosil?s unique 7740 composition of glass with low soda content ensures that the glass is highly resistant to external impact. This makes it ideally suited for use in solar applications where the collectors are exposed to hailstorms, animals, and falling objects.

Solar water heaters require little or no maintenance, while providing hot water all day, every day.