Heat recovery system at the Ottakringer brewery

The brewery in Ottakring produces around 740,000 hectoliters of beerper year. The annual energy requirement of the brewery amounts approximately 16,000 MWh.

For several years the brewery successfully worked on the improvement of the energy efficiency for the production process. The heat recovery measures will make a significant contribution to CO₂ savings.

Currently, the energy is supplied by a gas-fired boiler with a steam and a hot water supply (~ 120 ° C).

Within a further energy optimization, AEE INTEC developed a concept for the integration of a heat recovery system for the support of the hot water system.

Specifically, the supply of the existing hot water system was extended by the integration of waste heat from the chillers. This achieves a substitution of the energy supply of natural gas. By the successful implementation, a very good multiplying effect of the method to other breweries can be considered.

Usually about 1,900 MWh of energy are needed to heat the annual required amount of hot water of 25,000 m³ from 15°C to 80°C. With the integration of heat recovery, about 335 MWh of steam (or 420 MWh of natural gas, with a system efficiency of 80%) will be saved. In the Future, 84 tons of CO₂ can be avoided by the implementation annually (250 t_CO2 / GWh_nat.gas ^[1]).

Since the brewing process is only Monday to Thursday in operation and the bottling process from Monday to Friday, excess energy at weekends is stored in an additional hot water tank for a more efficient use of heat recovery. For the heat recovery system itself, a buffer with a volume of 30m³ is sufficient.

So that the waste heat from the chiller can be used efficiently, a buffer tank of 30m³ is required to cache the hot water produced by the waste heat. The hot water cannot be used immediately due to the alternating operation of the brewhouse and must be stored between the brews.

During the weekend in which there is no production, the buffered hot water can be used to the necessary refilling of the hot water tank in the brewhouse (100 m³) and the hot water tank (200 m³).

In this way a meaningful and efficient use of waste heat is ensured not only during the week but also on weekends.

Projektkonsortium und Funktion im Konsortium
AEE INTEC: Erstellung eines umfassendes Energieoptimierungskonzeptes.

[1] Kommunalkredit Public Consulting & Lebensministerium (2013) Betriebliche Umweltförderung, Förderungsberechnung, Version 03/2013