High-Temperature Solar Parabolic Trough Collector (PTC)

Parabolic trough collectors (PTC) are an advanced solar energy concentration technology widely used in renewable energy applications, particularly for industrial heat processes. Soliterm, a German company, specializes in designing, manufacturing, and deploying PTC systems to support various industries in reducing their reliance on fossil fuels.

Introduction to PTC Technology

Soltirem's parabolic trough collectors (PTC) utilize curved mirrors to concentrate sunlight onto a receiver tube, where a heat transfer fluid, such as thermal oil, is heated to temperatures between 100–250°C. These collectors are lightweight (13 kg/m²), making them suitable for rooftop and facade installations. They feature precise sun-tracking systems with ±0.1° accuracy for the PTC 1800 model and 0.01° for the overall system, ensuring maximum energy capture.

Key Features of PTC Collectors:

• Lightweight Design: Easy to install and maintain due to their low weight.
• High Precision Tracking: Sun-tracking accuracy of 0.01° (0.1° for the PTC 1800 model) optimizes efficiency.
• Enhanced Reflector Material: Coated aluminum minimizes reflection losses, boosting overall performance.
• Smart Control Systems: Soliterm integrates SCADA technology for remote monitoring and automated optimization.
• Hail Protection and Automatic Positioning: Ensures durability and performance in various weather conditions.

Manufacturing is carried out in a fully automated production facility with six stations, covering welding to packaging. The process is AI-driven, enabling the production of 40,000 collectors annually with a total thermal capacity of 250 MW, ensuring precision and consistency.

Industrial Applications

PTC systems are widely used in industrial applications where high-temperature heat is required. Below is an overview of their applications across various industries:

Process and Temperature Table:

Industry	Process	Temperature Range
Food & Beverage	Drying	30°C - 90°C
	Washing	40°C - 80°C
	Pasteurization	80°C - 110°C
	Cooking	95°C - 105°C
	Cleaning	140°C - 150°C
	Preheating	40°C - 60°C
Textile	Washing	40°C - 80°C
	Bleaching	60°C - 100°C
	Dyeing	100°C - 160°C
Chemical	Cooking	95°C - 105°C
	Distillation	110°C - 300°C
	Other Processes	120°C - 180°C
General Industry	Boiler Feedwater Heating	30°C - 100°C
	Factory Heating	30°C - 80°C
	Process Cooling	up to 60°C

Solar Cooling

Solar cooling technology utilizes heat from renewable energy sources, such as solar power, to drive cooling processes. This method is essential for industrial decarbonization, enabling industries to transition towards sustainable cooling solutions. The primary technologies include adsorption chillers, thermoacoustic cooling (THEAC), steam generation, and electricity production via ORC turbines.

Adsorption Chillers

Adsorption chillers leverage heat-driven adsorption processes to produce chilled water. Unlike absorption chillers, which use liquid solutions, adsorption chillers employ solid adsorbents, such as silica gel.

Working Principle:

Adsorption chillers function in two primary cycles:

1. Adsorption (Cooling) Phase: The adsorbent absorbs water vapor from the evaporator, triggering evaporation and generating a cooling effect. The resulting chilled water (7°C - 12°C) is utilized for air conditioning or industrial cooling.
2. Desorption (Regeneration) Phase: The second adsorbent bed is heated, releasing the absorbed water, which condenses in the condenser. The heat source for desorption is typically solar collectors or waste heat, operating at 50°C - 90°C.

• Cooling Capacity: Ranges from 10 kW to 500 kW, depending on system configuration.

Benefits of Adsorption Chillers:

• Energy Efficiency: Utilizes low-temperature heat sources, reducing dependency on electricity.
• Eco-Friendly: Uses water as a refrigerant, eliminating risks associated with ozone depletion and reducing global warming potential (GWP=0).
• Minimal Electricity Consumption: High efficiency with an Energy Efficiency Ratio (EER) of 33, significantly lowering operational costs. The cooling process does not require significant electricity input, reducing the carbon footprint.

More information: Eco-Prius - Adsorption Chillers - Cooling from Heat

Thermoacoustic Cooling (THEAC)

Thermoacoustic cooling is a technology that converts heat into cooling using sound waves. It utilizes thermoacoustic processes that do not require conventional mechanical components.

Operating Principle:

The THEAC system operates by using heat as a driving energy source to generate sound waves in a closed system. These waves cause compression and expansion of gas (e.g., argon), leading to heat transfer and the cooling effect. Efficient cooling is achieved without the need for synthetic refrigerants.

• Cooling temperature range: from -25°C to 0°C.

• Cooling capacity: from 25 kW to 250 kW (depending on configuration).

Advantages of Thermoacoustic Cooling:

• Maintenance-free: The absence of moving mechanical parts reduces maintenance requirements.

• Eco-friendly: Uses argon as a refrigerant (GWP=0).

• High durability: The estimated lifespan of the systems is up to 30 years.

More information: Eco-Prius - Thermoacoustic cooler

Steam Generation and Heat Pump Support

PTC (Parabolic Trough Collectors) can be used for direct steam generation or to support industrial heat pumps. With high efficiency in capturing solar energy, they enable steam production up to 130°C.

Operating Principle:

1. Steam Generation: Solar energy concentrated by PTC collectors heats the working fluid, which evaporates, allowing direct steam production for industrial applications.

2. Heat Pump Support: PTC collectors can serve as the lower heat source for heat pumps, raising the working medium temperature and allowing higher steam temperatures, significantly increasing COP. Industrial heat pumps from Ochsner range from 2 kW to 2500 kW.

More information: Eco-Prius - Industrial Heat Pumps

Electricity Generation from ORC Turbines

The Organic Rankine Cycle (ORC) technology enables the conversion of heat into electricity. It is used in combination with PTC collectors to generate energy from renewable sources.

Operating Principle:

Heat from PTC collectors heats an organic fluid with a low boiling point, which evaporates and drives a turbine generating electricity. After passing through the turbine, the vapor condenses, and the cycle begins again.

• Power range: from 10 kW to 1 MW (depending on the system).

Advantages of ORC Turbines:

• Efficiency: Enables conversion of both low and high-temperature heat into electricity.

• Modularity: ORC systems can be scaled to different power levels depending on demand.

More information: Eco-Prius - ORC Organic Rankine Cycle

PTC Concentrating Collectors - Product Line

Parabolic Concentrating Collector PTC 1800

Specifications of Soliterm PTC 1800 collectors:

Feature	Specification
Efficiency	500-700 kWh/m² (depending on conditions)
Weight of parabolic mirrors	13 kg/m²
Power	From 50 kW to 100 MW
Sun tracking accuracy	0.01° (overall system), 0.1° (PTC 1800)
Temperature range	100°–250°C
Thermal power	5 kW (PTC 1800)
Medium	Water / Steam / Thermal oil
Tracking type	Single-axis
Reflective paraboloid	Coated aluminum
Concentration factor	C = 43 (PTC 1800)
Collector length	5020 mm (PTC 1800)
Aperture	1800 mm (PTC 1800)
Weight	130 kg (PTC 1800)
Annual factory production capacity	40,000 collectors, total thermal power up to 250 MW

Cooperation with KfW Bank

Soliterm collaborates with KfW Development Bank, a German development bank that offers export loans for renewable energy projects outside Germany, including in Poland and Europe. KfW specializes in financing sustainable investments such as solar installations, supporting the energy transition. The cooperation includes access to preferential financing conditions, making it easier for companies to invest in Soliterm PTC systems. In Poland, KfW operates through local partner banks, offering loans for renewable energy projects, reducing the entry barrier for businesses (Loan (KfW Renewable Energy Standard)).

Examples of Completed Projects

Soliterm has completed numerous projects worldwide, providing PTC technology to industrial plants, public institutions, and the commercial sector. Examples of implementations include:

1. Beverage production plant in Spain:
   • Application: Water heating for washing and pasteurization processes.
   • Effect: Reduction of natural gas consumption by 30%.
2. Textile factory in India:
   • Application: Water heating for dyeing processes.
   • Effect: Reduction of energy costs by 25% and CO₂ emissions by 200 tons per year.
3. Hospital installation in Germany:
   • Application: Domestic water heating.
   • Effect: Energy savings of 40% and CO₂ emissions reduction by 150 tons per year.
4. Chemical plant in France:
   • Application: Production of process steam.
   • Effect: Reduction of gas consumption by 35% and significant decrease in operating costs.
5. Dairy farm in Austria:
   • Application: Water heating for equipment cleaning.
   • Effect: Reduction of energy costs by 28%.
6. Pharmaceutical factory in Italy:
   • Application: Sterilization processes.
   • Effect: Energy savings of 33%.