Solar Heat for Industrial Processes. Operating Plants and Potential for Application

R. Battisti1*, S. Drigo2 and C. Vannoni2

1 Ambiente Italia, Via Vicenza, 5/a 00185 Roma, Italy

2 University of Rome “SAPIENZA”, Department of Mechanical and Aeronautical Engineering,

Via Eudossiana, 18 00184 Roma, Italy

* Corresponding Author, riccardo. battisti@ambienteitalia. it
Abstract

The majority of the solar thermal plants operating today provide hot water to households, for both sanitary purposes and space heating. Although the residential sector offers a huge potential for solar thermal applications, the industrial sector should not be ignored for two key reasons.

First, this sector shows a remarkable relevance, covering about 28% of the total primary energy consumption for final uses in EU25.

Second, a significant share of the heat consumed in the industrial sector is in the low and medium temperature range. About 30% of the total industrial heat demand is required at temperatures below 100 °C and 57% at temperatures below 400 °C. The areas of application with the most suitable industrial processes include cleaning, drying, evaporation and distillation, blanching, pasteurisation, sterilisation, cooking, degreasing and surface treatment.

These two issues make the industrial sector a promising and suitable application for solar thermal energy.

In the paper, both the results of the analysis of the existing solar thermal plants for process heat and the assessment of the application potential will be described. Both activities have been carried out in the framework of IEA SHC and SolarPaces Task 33/IV.

Keywords: Solar Thermal, Industrial, Potential, Process Heat

1. Introduction

Considering the new applications for solar thermal, the industrial process heat at low and medium temperature up to 250 °C is one of the most promising. Industrial sectors such as food, wine and beverage, textile, transport equipment (e. g. car washing), surface treatment (e. g. galvanic) and the chemical require process heat in this temperature range. The areas of application are numerous and include different processes such as cleaning, drying, evaporation and distillation, blanching, pasteurisation, sterilisation, cooking, degreasing and surface treatment. In addition, several built examples showed that space heating of factory buildings has to be considered one of the most promising applications of solar thermal in industry.

A survey on the existing solar thermal plants for industrial process heat (SHIP, Solar Thermal for Industrial Applications) and a review of the potential studies for future applications have been

performed in the framework of the IEA Solar Heating and Cooling Programme and SolarPaces Task 33/IV: the results are summarised in the present paper.

At the end of 2006, the installed solar thermal capacity worldwide [1] was about 118 GWth (168 million m2). Compared with 144 GWel for wind and 5,5 GWel for photovoltaic, solar thermal is helding a leading position among renewables. The majority of the solar thermal plants operating today provide hot water to households. Although the residential sector offers a huge potential for solar thermal applications, the industrial sector should not be ignored for two key reasons.

First, this sector shows a remarkable relevance, covering about 28% of the total primary energy consumption for final uses in EU25 [2]. Second, a significant share of the heat consumed in the industrial sector is in the low and medium temperature range. These two issues make the industrial sector a promising and suitable application for solar thermal energy.