**1. Introduction**

Industrial sector demands large amounts of energy, two thirds of it is in the form of heat [1]. Of the heat demand in industry, almost half, 48%, is required for high temperature heat (more than 400 °C) mainly in the intensive industries of iron and steel and other minerals, which reach temperatures of up to 1450 °C; chemical and petrochemical, 900 °C; among others, 22% is used for medium-temperature heat (150 to 400 °C) and the remaining 30% is used for low-temperature heat (less than 150 °C) [2]. Currently, only 9% of the heat demand of industrial processes is supplied from renewable energy sources, 79% of solar thermal installations use flat plate solar collectors and evacuated tubes, 11% correspond to the use of paraboliccylinder collectors, and the remaining percentage of other technologies [3]. Chemical Vapour Deposition, CVD, plays an important role in the development and improvement of solar technology. CVD technologies have been innovating for at least 50 years to increase the efficiency of solar energy collection, both from solar cells and, more recently, from evacuated tubes [4].

When a protocol to solar heat for process industrial integration (SHIP integration) is being designed, there are some parameters that determine the solar heat integration potential: a) inherent to the process: energy demand [5], hourly heat

demand profile, seasonal heat demand profile [6], temperature intervals, continuous, semicontinuous or batch processes, different kinds of solar heat (steam, drying, hot water) [7]; b) regarding to the facilities: location [5], surface area availability; c) depending on the expected objectives: solar fraction, outlet temperatures, payback time, lower emissions of greenhouse gases (GHG), saving costs [8]. However, the picture is not complete if the limitations or restrictions that represent serious challenges to overcome to achieve efficient use of solar energy are not given equal importance: a) inherent to the process: higher process heat demand than solar heat produced; b) regarding to the facilities: limited flexibility of the systems, use of outdated or non-optimal technology for process conditions, higher costs of solar heating systems than fossil fuel conventional systems [6]. And all these considerations must in turn take into account energy policy and the associated investment, which can also limit or restrict the optimal use of solar energy: lack of economic support to research and innovation to tuning and updating of technology, lack of standard procedures for the implementation and evaluation of technological systems, difficulty promoting attractive investment and business models for the deployment and integration of renewable energies, and few market incentives [9], prohibitions to produce and distribute renewable heat [10], among other.

industrial sector when the transition towards the use of renewable energies is

expanded by defining some other objectives of industrial interest.

The methodology developed is general and can be used or coupled to medium temperature solar collectors or mixed systems (low and medium temperature solar collector technologies) for a specific application. The range of applications can be

The approach contemplates the integration of solar thermal energy into a real case, using low-temperature solar collectors, specifically, flat plate solar collectors, for the selection, design, and operation of the collector network. On the other hand, the design of the collector network is based on the most critical conditions of the year, which correspond to the winter period and guarantee the supply of the thermal load throughout the year. It is important to mention that the rest of the year there will be surplus energy that can be used in other applications. In the selected case study, two scenarios will be evaluated. In the first scenario, the total supply of the thermal load is considered at the temperature level required by the process, with a solar fraction of one and zero greenhouse gas emissions to the environment. In this scenario there are no space limitations for the installation of the solar collector network. In the second scenario, it is proposed that only 50% of the area required for the total supply of the thermal load is available, reducing the fraction as the generation of greenhouse gases. In this last scenario, it is analysed how the restrictions impact and what implications it has with the rest of the variables such as:

*Main stages that require thermal energy in an industrial process (green colour): Continuous process (a), batch*

sought to replace fossil fuels.

*Solar Energy in Industrial Processes*

*DOI: http://dx.doi.org/10.5772/intechopen.97008*

**Figure 1.**

*process (b).*

**457**

With the technologies that currently exist for the use of solar energy for heat production, the processes that demand low-temperature heat are the most convenient for integrating solar heat [11], besides, when solar storage is introduced, solar fraction increases markedly compared to a process without storage [5].

The evaluation of some of the restrictions or limitations such as: available installation space for the collector network, availability of capital or the low prices of the fossil fuels used and the supply time of the collector network, allows to evaluate the real impact of each scenario when compared with the one where there are no restrictions for the installation of the solar thermal device and thus seek the profitability of the device in whatever the scenario. Next, the proposed methodology for the integration of solar thermal energy with some real restrictions is described.

The objective of this chapter is to make a general approach that includes some real scenarios that arise when solar thermal energy is integrated into industrial processes, whether they operate continuously or in batches.
