Assessment of energy conservation/new energy systems in the brewing industry.

Brandon, B., Renaud, J., Staack, G. and Puskarz, S.

Abstract
The authors begin by pointing out that the United States is an extremely energy intensive society. They maintain that energy conservation is required as there is now a real possibility of an energy shortage and as the cost of energy has rocketed since the early 1970's. In the period 1973 to 77 the cost of oil increased by 170%. In the paper several possible energy conservation or new energy systems for the brewing industry are considered. The paper is a theoretical approach as only the technical and economic aspects of the systems are considered and not the practical problems associated with their installation and use. The paper attempts to formulate an overall analytical technique which can be used to assess the feasibility of implementing energy conservation and new energy systems. The first step in an energy conservation analysis is to determine what energy is currently being used in a system and how that might be reduced either by improved house keeping or investment or both. In this case a mathematical computer model was constructed to describe the various heat transfer mechanisms for the system under review. This included heat conduction within solids, radiation between surfaces and convection between surfaces and fluids. A detailed description is given of the energy model for calculating the optimum insulation thickness for a soak tank in a bottling plant. In most cases, energy conservation is only effected if it can be justified economically. The payback analysis method of economic evaluation is rejected in favour of the life cycle cost method as the former method discriminates against long lived projects by neglecting cash flows beyond the payback year. Many US Government Agencies are using the life cycle cost method for justifying energy conservation programmes. This method of economic analysis is described in detail and the financial assumptions on which the paper is based are outlined. The combined energy and economic analysis was applied to insulation, heat recovery and solar energy systems for pasteurisers and bottle washers. In each case, for example insulation, the various types were described in detail and the value of insulation was comprehensively demonstrated by a series of graphs. This thorough treatment was repeated for heat recovery systems in tunnel pasteurisers and liquid based solar heating systems. The paper concludes that this theoretical analysis works for some systems and would be suitable for many more if the price of fuel in the US increased from the current 55p per imperical gallon!
Keywords: brewing brewing industry electricity energy economisation gas heat insulation solar energy