9.1. Overview of Solar Heat for Industrial Processes

Industries all over the world use heat. Heat is heat, whether it comes from solar radiation or from fossil fuel combustion. Using solar thermal systems for generating heat for industrial processes is a very attractive avenue since it allows significant reduction in fuel costs and decreases environmental impact due to carbon emissions. Another reason is that a wide range of industrial applications require temperatures from near-ambient to those corresponding to low-pressure steam (<400 ^oC) - the range that fits very well the output temperatures of solar thermal collectors. So why not switch?

The key difference is the dispatchable nature of fossil fuels. Solar heat must be stored to achieve some level of dispatchability, or the industrial process that uses the heat must be flexible to adjust and only use the heat when the solar resource is available. Most often, some combination of a small storage solution along with modifications to the industrial process is the best solution.

At present ~40% of industrial primary energy consumption is provided by natural gas and ~41% by petroleum. So there is a technical potential to increase the share of solar thermal heat and possibly reach the solar thermal deployment in the industrial sector of 33% by 2030 (IRENA, 2015).

Many industries can be potentially benefitted, including but not limited to:

• Chemical processing
• Food production
• Beverage production
• Paper making
• Tanning
• Malt processing
• Desalination
• Textile
• Paint drying
• Masonry curing
• others..

The two key factors to consider in determination of the most suitable solar system for supplying energy to an industrial application are temperature and thermal medium. How much heat does the thermal fluid need to carry? What is the best type of fluid to use in the process?

For example, if hot steam is needed to operate an application, the solar system needs to be designed to deliver temperature significantly over 100 ^oC, and therefore concentrating collectors will be probably required. Or if hot water is needed (e.g. for such applications as desalination or sewage treatment), liquid-based flat plat collectors can be employed.

Learn more details on the status of solar energy implementation in different industries in the following report prepared by International Renewable Energy Agency: