Analysis of Potential Use of Linear Fresnel Collector for Direct Steam Generation in Industries of the Southwest of Europe

Abstract

Industry sector has an important impact on primary energy consumption at the international level, and solar energy constitutes a real alternative to cover these energy needs partially. Among thermosolar concentration technologies, Linear Fresnel Collector (LFC) technology has some advantages that make it more accessible to industries. With the aim of providing new tools for easier decision-making processes, in the present work, several energy audits were carried out in industries (located in the south-west of Europe, with considerable steam consumptions), quantifying thermal and energy consumptions and defining both work schedules and seasonality. Afterwards, a comparison based on three factors was carried out: Thermal consumption regarding total industry consumption, the performance of the work during the solar schedule, and the quantification of the monthly average concentrated energy for a certain LFC facility. The analysis carried out according to these criteria showed different results for each case, making a global assessment necessary to suitably ponder each factor. This analysis ranked tomato industries as the most suitable for LFC technology, due to the fact that their main operating period was during the months with the highest solar isolation, and the solar schedule was completely integrated in a 24-h working day. Also, industrial waxes and laundries showed a good combination of both facts.Energies 2019, 12, 4049 2 of 15 26% of primary energy consumption [16]. Furthermore, heat generation processes in industry constitute 54% of the total energy consumption in Europe in contrast with 17% of the total energy consumption corresponding to electric uses. This proportion of energy use justifies the implementation of solar thermal-based systems [17].Solar thermal systems harness solar energy for heating, either as hot water for domestic use-domestic hot water and heating-as a heating source for fluids in industrial processes or as steam to produce mechanical energy in a turbine to obtain electrical energy. Solar thermal systems may have concentrators to direct solar isolation that strikes the capturing surface area towards a smaller area (absorber area). This configuration obtains higher temperatures in the heat transfer fluid. These devices achieve solar concentration using specular reflection; thus, only direct isolation is used.There are two different technologies that concentrate direct solar isolation: Point focus type, that concentrates isolation into a single point-solar power tower or Dish-Stirling system-and linear focus type, which concentrates isolation into a linear receptor. Linear focus type reaches higher temperatures, because it concentrates isolation into a larger area. There are two types of linear focus collectors: Parabolic trough collector (PTC) and linear Fresnel collectors [18,19].Several studies have shown LFC (Linear Fresnel Collector) optical quality and thermal efficiency is slightly lower than in the case of PTC, due to the high influence of the angle of incidence and the cosine fa...

Design Factors in Concentrating Solar Power Plants for Industrial Steam Generation

“…In conclusion, it is a very promising technology in the field of industrial steam production, it is adapted to the requirements of this sector and its use can be favorable from a technical and economic point of view [18].…”

“…It is common to work with direct steam systems, but there are some industrial applications in which steam pressure needs are low [18], and in these cases, indirect heating installations that facilitate the control of the steam generation process may be of interest. Thus, the disadvantage of vapor formation inside the tubes is eliminated, and when working with moderate pressures and temperatures, water can be used as HTF, which avoids the environmental or safety drawbacks that characterize thermal oils.…”

“…Apart from the percentage of demand covered by the solar system, the profitability of the installation will be influenced by other factors, for example, the fuel that is intended to be replaced by the plant, its price, the seasonality of consumption [18], or possible subsidies from public administrations.…”

“…However, there are fewer studies focused on the integration of this type of plants in industrial processes, and they mainly target the viability of their use in different sectors and applications, or they focus on specific cases like low-temperature systems and flat plate collectors [14], [15], PTC or hot water production [16], [17]. F. J. Sepúlveda et al conducted a series of energy audits in several industries to analyze the potential for LFC implementation and the influence of different factors like the thermal energy ratio, the fraction of the working schedule that coincides with sunlight time, or the production seasonality [18].…”

Annual Thermal Performance of an Industrial Hybrid Direct–Indirect Solar Air Heating System for Drying Applications in Morelos-México

“…In recent years, solar heating for industrial processes has become an alternative to reduce fossil-fuel-burning and greenhouse gas emissions, making solar heating an issue in energy-related organizations and government agencies worldwide [6]. However, it is necessary to broaden the research to demonstrate the advantages of solar heating in the industrial process [7]. Drying is one of the most energy-intensive processes, representing around 12% of the manufacturing industry's energy consumption [8].…”