Recovering energy from excess heat at Gevalia’s roasting-house in Gävle

• Main Author: Zambars, Agnis
• Format: Others
• Language: English
• Published: Uppsala universitet, Naturresurser och hållbar utveckling 2013
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-236761

This thesis examines the roasting process at Gevalia’s coffee roasting house in Gävle and describes the possibilities to recover the energy in roasting gasses that are released into the atmosphere from the factory’s chimneys. The roasting gasses leave the factory’s chimneys at temperatures upwards of 370 °C in large volumes all year round. It is possible to extract energy from them via an economiser. The extracted energy can then be used to replace Gevalia’s consumption of district heating. The estimated potential for energy extracted from the roasting gasses is approximately 10 GWh per year. The monetary gain can be estimated up to 5 million SEK annually if it is possible to sell excess heat into the local district heating grid. It remains uncertain if it is possible to sell the excess heat due to a number of regulations and other external factors. Should this not be possible, the factory can still cover their own heating demand through heat recovery from roasting gasses. An alternative solution to economiser is absorption cooling in order to produce refrigeration. This process, however, is more complicated. There is also a very limited number of cooling consuming elements within the factory. A planned extension of the local district cooling grid in the area could make this a more viable alternative. The estimated potential for cooling production is approximately 7,6 GWh per year.