Heat pumps for energy efficient breweries.

The article analyses and describes the energy flows in a modern brewery, as planned to be realized in the southern part of Norway. Based on the heating and cooling demands a new concept is developed to enable an innovative and efficient surplus heat upgrade, applied to eliminate current fossil fuel burners. Initially focus is given to minimizing the necessary steam demand in the plant, since the energy efficiency can be increased by substituting this high-quality energy source by pressurised hot water, which can be directly produced by heat pumps. As a result of different system evaluations, the final recommendation is to install an energy storage tank and two heat pump systems with different supply temperature levels. Both heat pumps are utilising the residual heat generated in the tank farm (fermentation) and from the residual water. The first system should be an ammonia heat pump followed by a butane heat pump to produce steam, which also can be stored in a steam accumulator. The second unit should be a carbon dioxide heat pump applied to produce water at 100 ºC. The hot water is stored in a stratified tank with water at temperature levels above 85 ºC.