Matthias Rommel

Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg, Germany

matthias. rommel@ise. fraunhofer. de

Abstract

A large share of the energy which is needed in commercial and industrial companies for production processes is below 250°C. Solar collectors for the temperature level up to 80°C are already on the market. But new and advanced collector technologies are needed for the higher temperature levels between 80°C and 250°C.

Several new development activities on process heat collectors have been started in the last years. Many, but of course not all of them were somehow linked to Subtask C of the IEA-SHC Task 33/Solar PacesIV "Solar Heat for Industrial Processes" which was carried out under the Solar Heating and Cooling Programme SHC of the International Energy Agency IEA. The paper gives an overview on these collector developments.

Also Fraunhofer ISE is involved in different collector development activities for process heat applications. In order to carry out high quality R&D work in this field together with the solar industry, a new collector testing facility was set up which allows to measure efficiency curves for collector operating temperatures up to 200°C.

Keywords: process heat collectors, industrial process, IEA SHC Task 33, SHIP, collector testing

1. Introduction

As reported by Weiss et al. in [1], the solar thermal collector capacity in operation worldwide in 2006 equalled 127.8 GWth corresponding to 182.5 million square meters at the end of the year 2006. Of this, 102.1 GWth were accounted for by flat-plate and evacuated tubular collectors and 24.5 GWth for unglazed plastic collectors. Air collector capacity was installed to an extent of 1.2 GWth.

The solar heat is mainly used in the household sector for domestic hot water and room heating. In contrast to that, the use in commercial and industrial applications is very limited up to now. On the other hand, the industrial sector in the OECD countries has the highest share of the total energy consumption, at approximately 30%. Solar heat for industrial processes is therefore an important field with a high potential of conventional energy savings, reduction of CO2 emission and economical interest for the solar thermal industry in Europe and world-wide.

A large share of the energy which is needed in commercial and industrial companies for production processes is below 250°C. Solar collectors for the temperature level up to 80°C are already on the market. But new and advanced collector techniques are needed for the higher temperature levels. Especially collectors for operating temperatures between 80°C and 250°C are of interest.