— Solar Water Heater —

ETC SOLAR WATER HEATERS

ETC solar water heaters use advanced evacuated glass tubes to convert sunlight into heat, providing an efficient and consistent supply of hot water throughout the year. Designed for India’s diverse climates, they perform well even in cold regions, require minimal maintenance, and offer a cost-effective, eco-friendly alternative to traditional water heating systems.

Design

The design of an ETC (Evacuated Tube Collector) solar water heater is simple yet highly efficient. It consists of multiple borosilicate glass tubes, each made up of two concentric glass layers with a vacuum in between. This vacuum acts as insulation, minimizing heat loss and allowing maximum solar absorption.

Each tube contains an inner coated surface that absorbs sunlight and transfers the heat directly to the water flowing through the tubes. The heated water then rises naturally (by thermosiphon effect) into an insulated storage tank, while cooler water from the tank moves down into the tubes to be heated again.

The system usually includes:

• Evacuated glass tubes – for heat absorption

• Insulated water tank – to store hot water for long durations

• Support frame – to hold the tubes at an optimal tilt angle facing south

This design makes ETC systems efficient, durable, and effective even in low sunlight or cold climates, making them ideal for use across India.

Benefits

1. High Efficiency: Works effectively even in cold or cloudy weather.

2. Low Maintenance: Durable glass tubes with minimal upkeep.

3. Long Lifespan: Lasts up to 15–20 years.

4. Cost Savings: Cuts electricity bills by up to 70%.

5. Eco-Friendly: Reduces carbon emissions with clean solar energy.

 Subsidy: Eligible users can get up to 40% government subsidy on installation, making it more affordable.

FPC SOLAR WATER HEATERS

A Flat Plate Collector (FPC) solar water heater uses flat, insulated panels to absorb sunlight and convert it into heat for water heating. It’s a reliable and long-lasting solution widely used in homes, hotels, and industries across India. These systems are ideal for regions with strong sunlight and moderate weather conditions, offering consistent hot water throughout the year.

Design

The FPC solar water heater consists of a flat collector panel made of insulated metal box housing copper or aluminum absorber plates. These absorber plates are coated with a selective coating (usually black chrome or nickel) that helps capture maximum solar radiation while minimizing heat loss.

Each panel is covered with a toughened glass sheet that allows sunlight to pass through but traps heat inside, creating a greenhouse effect. Beneath the absorber plate, copper tubes carry water, which gets heated as the plate absorbs solar energy. The heated water naturally rises (thermosiphon effect) into an insulated storage tank, while cooler water flows back into the collector for reheating.

The entire setup is mounted on a sturdy, south-facing support frame tilted at an optimal angle to maximize solar exposure. This simple yet effective design makes FPC systems durable, weather-resistant, and highly efficient for consistent water heating throughout the year.

Benefits

1. High Durability: Made from corrosion-resistant materials for a long lifespan.

2. Efficient Heating: Performs best in areas with ample sunlight.

3. Low Maintenance: Strong design requires minimal upkeep.

4. Cost Savings: Reduces electricity or fuel costs by up to 70%.

5. Eco-Friendly: Uses renewable solar energy, cutting down carbon emissions.

Subsidy: The Government of India offers up to 40% subsidy on FPC solar water heater installations under renewable energy schemes, making them more affordable for households and businesses.