A solar water heater comprises two major types which are closed loop systems and open loop systems. The system has a collector, pipelines and storage tank. A system with a capacity of 100-300 liters is suitable for domestic application. In clear sunny day it raise the temperature of cold water to 80C but it works poorly in partially clouded and rainy days.
A solar water heater is made up of a collector that collects solar energy and a storage tank which is insulated serving the purpose of storing hot water. Solar water heater utilizes solar energy. Risers are used for heating up water before delivering to the storage tank. During sunny day the absorber panel found in the collector increases the temperature of the water to 80 C. the whole system is made up of storage tank, pipelines and solar collector.
1. Types of solar water heating structures
- Closed loop systems which are made up of heat exchangers for protection from hard water obtained from boreholes in low temperatures in cold areas.
- Open loop systems: either forced circulation system or thermosyphon are used, water present in the system are exposed to the atmosphere during the heating process. These systems are appropriate for small institutional and domestic systems so long as the water is of good quality. Forced circulation systems uses electrical pumps to facilitate circulation of water via the collectors and the storage tank.
2. Flat plate collectors solar water heating system
Flat plate collector is made up of insulated metallic box with a glass sheet cover at the top. Absorber sheet are present at the inner side containing water channels. In this system the radiation from the solar is assimilated by flat plate collector.
3. Evacuated tube collector solar water heater
This consists of double-layered borosilicate glass tubes. The outer side of the interior tube is made of best quality absorbing and selective coating material which aids in absorbing the radiation from the solar system and transmit heat to the water flowing through the inner tube.
4. Features of solar water heater
A solar water heating system changes cold water into hot water with the aid of solar energy from the sun. The following are the highlights of its features.
- Depending of the strength of the solar radiation, condition of the weather and the efficiency of the system a temperature of 80 degrees Celsius can be attained.
- Installation of the system can be made on an open ground, building terrace or at the rooftops, no shading is required for proper sun rays absorption.
- It generates hot water during good sunny days but it cannot in rainy days.
- Larger tanks are made of anti-corrosive coat at the inner side while smaller tanks are made of stainless steel.
- A system with a capacity of 300 liters is suitable for domestic purposes.
- Advantages of this heating system.
It replaces electrical geyser for residential applications, almost 1500 electricity units are saved annually.
Avoids utility cost on generation
The use of 100 solar water heater with a capacity of 100 liters contributes to a load of 1MW saving on the cost of generation.
Solar water heater is environmental friendly it prevents harmful production of carbon dioxide. This prevents the related health hazard of harmful pollutants.
A solar water heater works effectively in clearly sunny days and poorly in partially clouded and rainy days. It changes cold water into hot water, its applications is accompanied by merits; it saves on cost of fuel, prevents environmental pollution and saves on generation cost.