A Parabolic Trough Collector consists of a long, curved reflector (parabolic in shape) that focuses direct solar radiation onto a linear receiver (absorber) tube positioned at its focal line. A heat transfer fluid (HTF), typically synthetic oil or pressurized water, flows through the receiver tube and absorbs the concentrated solar heat.
Technical Specifications
| Parameter | Typical Values |
| Collector Type | Line-focusing, single-axis tracking |
| Concentration Ratio | 15:1 to 45:1 |
| Operating Temperature | 150°C – 400°C |
| Thermal Efficiency | 60% – 75% (depending on design and conditions) |
| Heat Transfer Fluid (HTF) | Synthetic oil, thermal water, steam, or molten salt |
| Tracking System | Single-axis (East–West tracking) |
| Structure Material | Aluminum/steel with glass or polished mirror |
| Receiver Coating | Selective coating to reduce thermal losses |
Applications
- Industrial Process Heat
- Used in industries like food processing, dairy, textiles, and pharmaceuticals for heating, pasteurization, or drying.
- Example: Solar steam generation for cleaning and sterilization.
- Power Generation
- Forms the core technology in solar thermal power plants (CSP) using Rankine cycle with steam turbines.
- Suitable for both standalone and hybridized power stations.
- Desalination
- Provides thermal energy for membrane distillation or multi-effect distillation (MED) systems in coastal or arid regions.
- Hot Water and Steam for Communities
- Community kitchens, hospitals, and educational institutions can use PTCs to supply large volumes of hot water or steam.
- Example: Supplying 1000 litres of boiling water daily for tribal communities in Pachamalai Hills, Tamil Nadu.
- Air Conditioning and Cooling
- When coupled with absorption chillers, PTCs can provide solar-assisted cooling systems for commercial buildings or rural health centers.
Comparison of Solar Collector Technologies
| Parameter | Flat Plate Collector (FPC) | Evacuated Tube Collector (ETC) | Parabolic Trough Collector (PTC) | Solar Dish/Heliostat (Dish/Tower) |
| Technology Type | Non-concentrating | Non-concentrating | Concentrating (Line-focus) | Concentrating (Point-focus) |
| Tracking Required | No | No | Yes (Single-axis) | Yes (Dual-axis) |
| Operating Temp. Range | 30°C – 80°C | 40°C – 120°C | 150°C – 400°C | 500°C – 1000°C |
| Efficiency | 30% – 50% | 40% – 60% | 60% – 75% | 70% – 85% |
| Suitable Applications | Domestic hot water, small-scale heating | Solar water heating, medium temp. uses | Industrial process heat, power gen. | Power generation (CSP), high-temp. heat |
| Cost (relative) | Low | Moderate | High | Very High |
| Installation Complexity | Easy | Moderate | Complex | Very Complex |
| Space Requirement | More area required | Moderate | Less than FPC/ETC for same output | High (large tracking systems) |