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How Demax Solar Thermal Systems Provide Industrial Process Heat
Matching solar thermal output to important industrial temperature ranges (80–400°C)
McKinsey explains that the highest demand for industrial heating (over 50%) occurs at heating requirements below 400 degrees Celsius. Demax therefore focuses their technology for the 400°C range. This is where most of the industrial processes in the United States operate. This flexibility spans across different industries, ranging from food processing plants with heating requirements from 100 to 250 degrees, to chemical manufacturers that typically operate around 300 to 400 degrees. Their modular design means that there is no energy wasted as they meet the requirements of any particular process. Additionally, they provide completely clean heating for the sterilization of equipment, drying of products, and running of distillation processes.
Core technology: Integration of parabolic troughs and evacuated tubes in modular solar thermal arrays.
The Demax system integrates two types of solar technologies. First, parabolic troughs that concentrate the sun's direct rays on heat receiver tubes with outputs of 150 to 400 degrees Celsius, which operate best under direct sunlight. Then, the system uses vacuum sealed evacuated tubes that are great at capturing heat, even when the light is diffuse, which are excellent for lower temperature applications. When implemented as hybrid architectures, research shows efficiency is boosted in as much as 24% over single technology systems. Each module is about 500 square meters in size and generates about 0.5 megawatt thermal energy. This modular design enables firms to deploy units in stages as their production requirements grow or as their plants are upgraded.
Why Low-Concentration CSP Is Better Suited for Industrial Solar Thermal Uses
Benefits compared to high-concentration CSP: More efficient <250 °C operation, lower O&M, superior performance at partial-load conditions
When it comes to operation temperatures about around 250 °C, low concentration CSP is superior to high concentration CSP because it is able to provide improved thermal efficiency in steam applications, including food processing and textile dyeing applications, by about 15 to 25%. The reason for this is that low concentration CSP uses less complicated optics and tracking systems which also means less day to day operational complexity, which in turn results in a 30% reduction in operational maintenance cost, a significant reduction in maintenance downtime, and consistent thermal energy output, despite changing solar radiation conditions throughout the day. A thermofluid stability study conducted in 2023 demonstrated that factories can operate thermally fast during the day and can also be thermally flexible during cloudy days.
Demax's design philosophy focuses on the reliability, thermal integration, modular scalability, and direct thermal delivery method that minimizes loss during electrical conversion.
The engineering team at Demax focuses on three specific areas in their designs. First, delivery methods that are thermal only. They have recorded that approximately 97% of solar energy captured is utilized in direct thermal capture, which is impressive in comparison to other methods. Second, The modular design of their solar thermal arrays allows for easy expansion of the system, which eliminates the need for extensive changes in the system design. Small scale installations start at 500 kWth, however, they can be expanded to multiple megawatts. Additionally, the system components can be operated continuously day after day. Real world testing has demonstrated that their components experience less than 1% degradation per year, even in extreme operating conditions. This combination of design choices allows the manufacturers to have the most important aspects of their systems: consistent and reliable thermal energy generation without the hassle of conventional systems.
Integrating Solar Thermal Systems with Industrial Processes
Example: Solar Thermal system of 1.8 MWth providing 125°C steam for food processing in Spain (2023)
In 2023, a food processing plant in Spain, fitted with a 1.8 MWth Demax solar thermal system, was the first of its kind in the country that was able to produce steam at the 125°C required for the sterilization and cleaning of the steam. This system is integrated with one of the company’s existing boiler systems and it has a large 2300 m2 solar evacuated tube array which was able to provide a natural gas reduction of approximately 28%. This setup results in an annual reduction of approximately 420 metric tons of CO2 emissions. Moreover, with Spain’s high solar irradiation and competitive industrial energy pricing, it was financially viable for the company to operate the system at a full capacity because the installation was economically self-recovering in less than 5 years. This is particularly advantageous for companies where the majority of their thermal energy demands occur during the day and coincide with the availability of solar thermal energy.
Overcoming intermittency: PCM-based thermal storage enabling 6–10 hour dispatchable heat supply
Phase change materials (PCMs) thermal storage helps tackle the intermittency problem of solar energy for industrial use. An example of this is the Spanish factory using salt hydrate PCMs capsules. These PCMs absorb excess heat at about 118 degrees Celsius and release the stored heat as steam at a later time, enabling the factory to operate at night without fossil fuels for backup. This factory has also achieved about 92% annual use of solar energy, significantly higher than the typical 60-70% of other facilities that use solar thermal without any storage. PCM technology has been a true game-changer for manufacturers belonging to the food, pharmaceutical and chemical industries where a constant supply of heat is crucial for operations.
FAQ
What temperature range do Demax solar thermal systems target?
Demax solar thermal systems target industrial heating requirements as low as 400 degrees Celsius.
Why is low-concentration CSP preferred for industrial applications below 250°C?
Above 250 degrees Celsius, operational/maintenance costs, as well as potential heat output fluctuations, are issues. Below 250 degrees Celsius, low-concentration CSP systems are cheaper to operate and maintain, and they are more effective at meeting steady heat output demands, as lows and fluctuations in input heat from sunlight is not an issue.
What are the core technologies in Demax's solar thermal systems?
Demax has modular solar thermal arrays that combine parabolic troughs and evacuated tubes. This technological integration results in a 24 percent gain in efficiency, in contrast to systems that operate using only one technology.
How does the Demax system integrate into existing industrial processes?
With the Demax system, existing industrial processes remain the same, as modifications are made only to the boiler systems. This change allows processes to utilize less natural gas and emit lower amounts of carbon.