Integration of Solar Heating Systems for Process Heat. Generation in Breweries

B. Schmitt*, K. Vajen and U. Jordan

Kassel University, Institute of Thermal Engineering, 34125 Kassel (Germany)
* Corresponding Author, solar@uni-kassel. de


The generation of process heat for industrial applications seems to be a promising market for solar thermal systems. Processes in several industrial sectors consume high amounts of thermal energy at a low to medium temperature level. These boundary conditions are given in the food and beverage industry, especially in breweries. In this paper, basic information are given for the implementation of solar heating systems in breweries.

Using the Hutt brewery in Kassel (Germany) as example, the diversity in brewing processes is shown. Although all breweries consume large amounts of thermal energy for the wort production, every single brewery has to be analysed relatively detailed. To estimate a reasonable integration of a solar heating system, a detailed water and energy balance has to be drawn. The strong influence of the existing or available installations on a solar heating system is shown by two different concepts for the Hutt brewery. Therefore, it will be difficult to develop general guidelines for a suitable implementation of solar heating systems in breweries.

Keywords: solar process heat, industrial processes, brewery, energy efficiency

1. Introduction

By the year 2006, approximately 128 GWth of solar thermal collectors had been installed worldwide. Most of the installed systems were used for domestic hot water preparation, space heating or swimming pool heating [1]. So far approximately 90 solar heating plants with a total capacity of 25 MWth were used for industrial applications, which is a nearly negligible share of 0.02%. Within the framework of IEA SHC Task 33/IV, the potential for industrial applications within the EU 25 was estimated to be between 100 and 125 GWth. This huge potential is based on two facts: Firstly, the industry sector consumes nearly 30% of the total primary energy consumption in the EU25 and secondly, a significant share of the heat consumed in this sector is in the low and medium temperature range [2]. Approximately one third of the total industrial heat demand is required at temperatures below 100°C and nearly 60% at temperatures below 400°C. In some of the industrial sectors, such as food, wine and beverage, transport equipment, textile, pulp and paper, the share of heat demand below 250°C can be as large as 60% [3].

The food and beverage industry is one of the key sectors for solar heating, since processes such as cleaning, drying, pasteurisation, sterilisation or boiling take place at a low temperature range and the overall energy consumption is large [4]. To realise a significant implementation of solar heating systems within this industry sector, it has to be analysed which part of the high heat demand at a low and medium temperature level could be provided by solar heating systems, how to
integrate these systems in already existing processes and finally, how to transfer this knowledge to similar processes or other sectors.

Within the food and beverage sector, breweries show a large heat demand at relatively low temperature levels, but also a large potential for heat recovery. The brewing sector is furthermore interesting because of the large amount of breweries in Europe and especially Germany. All over Europe, there are more than 2,800 breweries, nearly half of them is located in Germany. Almost 85% of all German breweries are small and medium sized companies (SME) with an annual beer production of 50,000 hl or less [5]. In 2006, about 4.3 TWh (15.5 PJ) of energy was consumed in almost 1,300 German breweries, only one fourth of the consumed energy was electricity [6].

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