Heating of solar thermal power stations
Safe plant operation thanks to efficient heat tracing systems
Electrical heat tracing in CSP plants is necessary to prevent molten salt from solidifying or freezing (from 260 °C), heat transfer oil, synthetic oil (15 °C) and water or condensation (0 °C), or to preheat pipes and systems. Its main function is to preheat empty pipes and systems, to maintain the desired temperature throughout the entire process and thus prevent the liquids from solidifying.
Ensure that viscous fluids remain free-flowing and pumpable
An optimally designed heat tracing system converts electrical energy into heat, thereby preventing heat loss from the pipe to the surrounding environment. Electrical trace heating is essential in CSP plants, particularly for the thermal energy storage (TES) system and the plant’s own power supply and emergency power systems.
A carefully planned heat tracing system ensures a smooth process and helps to prevent costly blockages in pipework. A poorly planned heat tracing system can lead to high costs, which may negatively impact the plant’s overall profitability. It is therefore essential to have a reliable and experienced partner who can supply the complete system for your CSP plant, including engineering, commissioning and design.
Accounting for less than one per cent of the total project budget, electric trace heating is a small yet crucial investment and, at the same time, a vital part of the overall project. A lack of experience in this area can lead to major and costly problems and jeopardise the entire project. eltherm offers flexible and cost-effective turnkey solutions, from data transfer through to commissioning; including optimal design and user-friendly operation and maintenance. Selecting the appropriate heating cable for the specific process is essential.
Commonly used technologies, such as parabolic troughs, linear Fresnel reflectors or the Dish-Sterling system, use heat transfer oil to drive the turbine, which then generates electricity. This oil must be maintained at a precise temperature to remain fluid.
Another key area is the heating and temperature control of molten salt. Solar thermal tower power stations, for example, use liquid salt as a heat transfer fluid to improve system performance. The holding or operating temperatures in this application are very high: up to 400° or 565°C, depending on the type of plant. This is where our mineral-insulated ELK-MI heating cables come into play. These cables deliver extremely high power output at the highest operating temperatures and are therefore the best solution for high-temperature applications, even in aggressive environments. They are extremely durable, moisture-resistant and mechanically robust.
The joining of mineral-insulated heating cables is a critical aspect: only high-precision laser welding technology guarantees a secure and reliable joint of consistent quality. eltherm employs this advanced technology as standard for mineral-insulated heating cables. The joints are completely vapour-tight and free from harmful flux residues. Non-soldered joints allow for maximum flexibility. It is even possible to laser-weld stainless steel or Alloy 825. Laser-welded joints reduce both installation costs and service and maintenance costs.
Key facts
- Consistent, reliable temperature control
- Centralised monitoring
- Prevents molten salts from solidifying or freezing
- Reduction in downtime thanks to constant temperature
FAQ
It gets cold at night even in the desert. That is why the salts and the heat transfer oil must be kept at a temperature above 15 °C to protect them from frost during the night
Among other things, components must be heated during transport and storage, as must pipework, valves and pumps, to prevent frost forming at night.
