Passive & Indirect Solar Water Heating System

Product Overview

Our Passive Indirect Solar Water Heating System provides reliable, clean, and energy-efficient hot water using solar energy. Operating on thermosiphon circulation, it requires no pumps or complex controls.

A closed-loop heat transfer circuit circulates fluid naturally through the collectors and storage tank. Heat is transferred to domestic water via a built-in heat exchanger, keeping water hygienic, scale-free, and safe—ideal for hard water areas.

Durable stainless steel construction, high-efficiency flat plate collectors, and thick insulation ensure long-lasting performance with minimal maintenance.

Technical Specification
Model PIS 150 PIS 200 PIS 300
Tank Capacity (Litres) 150 L 200 L 300 L
Collector Type Flat Plate Collector Flat Plate Collector Flat Plate Collector
Number of Collectors 1 2 2
Collector Area (Approx.) 2.0 m² 4.0 m² 4.8 m²
System Type Passive, Indirect (Thermosiphon) Passive, Indirect (Thermosiphon) Passive, Indirect (Thermosiphon)
Inner Tank (Heat Exchanger) Copper Coil / Stainless Steel Coil (Option) Same Same
Outer Tank Material Stainless Steel (SUS 304/316)** Same Same
External Casing Colorbond / Stainless Steel Same Same
Insulation Polyurethane Foam (PUF) PUF PUF
Insulation Thickness 50 mm (Typical) 55 mm 55 mm
Maximum Operating Pressure 0.8 bar 0.8 bar 0.8 bar
Orientation Horizontal Horizontal Horizontal
Mounting Compatibility Flat Roof / Pitched Roof Flat Roof / Pitched Roof Flat Roof / Pitched Roof
Heat Transfer Mechanism Closed-Loop Natural Thermosiphon Same Same
Temperature Rating (Max.) 90°C 90°C 90°C
Collector Tubing Material Copper Tubes Same Same
Collector Absorber Plate High-Efficiency Selective Coated Plate Same Same
Glazing Material Tempered Low-Iron Solar Glass Same Same
Collector Frame Material Aluminum Alloy Same Same
Tank Heat Preservation Duration 48–72 Hours (Depending on Climate) Same Same
Recommended Household Size 2–3 Persons 3–4 Persons 5–7 Persons
System Weight (Empty) ~110 kg ~150 kg ~200 kg
System Weight (Full) ~260 kg ~350 kg ~500 kg
Tilt Angle Requirement 15°–45° 15°–45° 15°–45°
Heat Transfer Fluid Water / Glycol Mix (for frost protection) Same Same
Warranty 5 Years (Tank & Collectors) Same Same
Illustration