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International Journal of Chemical Engineering
Volume 2010 (2010), Article ID 627930, 10 pages
http://dx.doi.org/10.1155/2010/627930
Research Article

Energy from Waste: Reuse of Compost Heat as a Source of Renewable Energy

School of Engineering, Institute for Infrastructure and Environment, University of Edinburgh, William Rankine Building, The King's Buildings, Edinburgh EH9 3JL, UK

Received 10 December 2009; Accepted 14 April 2010

Academic Editor: Michael K. Danquah

Copyright © 2010 G. Irvine et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An in-vessel tunnel composting facility in Scotland was used to investigate the potential for collection and reuse of compost heat as a source of renewable energy. The amount of energy offered by the compost was calculated and seasonal variations analysed. A heat exchanger was designed in order to collect and transfer the heat. This allowed heated water of 4 7 . 3 o C to be obtained. The temperature could be further increased to above 6 0 o C by passing it through multiple tunnels in series. Estimated costs for installing and running the system were calculated. In order to analyse these costs alternative solar thermal and ground source heat pump systems were also designed. The levels of supply and economic performance were then compared. A capital cost of £ 11,662 and operating cost of £ 1,039 per year were estimated, resulting in a cost of £ 0.50 per kWh for domestic water and £ 0.10 per kWh for spatial heat. Using the heat of the compost was found to provide the most reliable level of supply at a similar price to its rivals.