an official journal of: published by:
Editor in Chief: RAFFAELLO COSSU


  • Geo Jacob - Department of SciTec, Ernst-Abbe-Hochschule Jena, Germany - Department of Bioenergy Systems, DBFZ Deutsches Biomasseforschungszentrum gemeinnutzige GmbH, Germany
  • Frank Dienorowitz - Department of SciTec, Ernst-Abbe-Hochschule Jena, Germany
  • Nele Jaschke - Department of Bioenergy Systems, DBFZ Deutsches Biomasseforschungszentrum gemeinnutzige GmbH, Germany


Released under CC BY-NC-ND

Copyright: © 2022 CISA Publisher


Composting experiments with heat recovery reveal spatial non-uniformity in parameters such as temperature, oxygen concentration and substrate degradation. In order to recover heat from static compost piles via integrated heat exchanger there is the need to investigate the temperature distribution for placing the heat exchangers and the interaction between heat recovery, substrate degradation and oxygen concentration to ensure quality of composting process. This study introduces a spatial model to predict the variation in controlling parameters such as temperature, oxygen concentration, substrate degradation and airflow patterns in static compost piles with heat recovery using Finite element method (FEM) in COMSOL Multiphysics ® Version 5.3. The developed two-dimensional axisymmetric numerical model considers the compaction effects and is validated to real case pilot-scale compost pile experiments with passive aeration. Strong matching with the real case experiment was achieved. The spatial model demonstrated that the compaction effect is extremely important for realistic modeling because it affects airflow, temperature distribution, oxygen consumption and substrate degradation in a compost pile. Heat recovery did not disrupt the composting process. Case studies revealed strong influence of convective heat loss through the edges and a 10 % improvement of heat recovery rate with ground insulation. The simulation indicates that an optimized placing of heat recovery pipes could increase the average heat extraction by 10-40 %.


Editorial History

  • Received: 26 Feb 2022
  • Revised: 03 Jul 2022
  • Accepted: 03 Aug 2022
  • Available online: 14 Sep 2022


DWD Climate Data Center. (n.d.). Hourly station observations of air temperature at 2 m above ground in °C for Germany, version v19.3. Retrieved 10 10, 2019, from

COMSOL Multiphysics® v. 5.3. (2019). Stockholm, Sweden: COMSOL AB.

Das, K., & Keener, H. M. (1997, March 01). Moisture effect on compaction and permeability in composts. Journal of environmental engineering(3), pp. 275-281.
DOI 10.1061/(ASCE)0733-9372(1997)123:3(275)

Deipser, A. (2014). Prozesssimulation biologischer Abbauprozesse im Bereich der Abfallwirtschaft. Technische Universität Hamburg. Hamburg: Gesellschaft zur Förderung und Entwicklung der Umwelttechnologien an der Technischen Universität Hamburg-Harburg e.V. (GFEU).
DOI 10.15480/882.1181

European Environment Agency. (2017). Energy and mitigating climate change. Retrieved April 1, 2019, from

Finger, S. M., Hatch, R. T., & Regan, T. M. (1976). Aerobic microbial growth in semisolid matrices: heat and mass transfer limitation. Biotechnology and Bioengineering, 18(9), 1193-1218.
DOI 10.1002/bit.260180904

Hamelers, H. V. (2001). A mathematical model for composting kinetics. Wageningen University. Wageningen, Netherlands: Wageningen University.

Haug, R. T. (1993). The Practical Handbook of Compost Engineering. Boca Raton, Florida: CRC Press.
DOI 10.1201/9780203736234

Jaschke, N., & Schmidt-Baum, T. (2021). Heat Recovery of Compost Reactors: Field Study of Operational Behaviour, Heating Power and Influence Factors. Ecological Chemistry and Engineering, 28(2), 201-217.
DOI 10.2478/eces-2021-0015

Liang, Y., Leonard, J. J., Feddes, J. J., & McGill, W. B. (2004). A simulation model of ammonia volatilization in composting. Transactions of the ASAE(5), p. 1667

Luangwilai, T., & Sidhu, H. (2010). Determining critical conditions for two dimensional compost piles with air flow via numerical simulations. ANZIAM Journal, 52, 463-481.
DOI 10.21914/anziamj.v52i0.3753

Luangwilai, T., S. Sidhu, H., & Nelson, M. I. (2012). Understanding the role of moisture in the self-heating process of compost piles. Chemeca 2012: Quality of life through chemical engineering: 23-26 September 2012. Wellington, New Zealand. Retrieved from

Luangwilai, T., Sidhu, H. S., & Nelson, M. I. (2018). One-dimensional spatial model for self-heating in compost piles: Investigating effects of moisture and air flow. Food and Bioproducts Processing, 108, 18-26.
DOI 10.1016/j.fbp.2017.12.001

Luangwilai, T., Sidhu, H. S., Nelson, M. I., & Chen, X. D. (2010). Modelling air flow and ambient temperature effects on the biological self‐heating of compost piles. Asia‐Pacific Journal of Chemical Engineering, 5(4), 609-618.
DOI 10.1002/apj.438

Luangwilai, T., Sidhu, H. S., Nelson, M. I., & Chen, X. D. (2010). Modelling air flow and ambient temperature effects on the biological self‐heating of compost piles. Asia‐Pacific Journal of Chemical Engineering, 5(4), 609-618.
DOI 10.1002/apj.438

Lukyanova, A. (2012). Spatial Modeling of the Composting Process. Edmonton, Alberta: University of Alberta.
DOI 10.7939/R3DN4065R

Malesani, R., Pivato, A., Bocchi, S., Lavagnolo, M. C., Muraro, S., & Schievano, A. (2021, May 1). Compost Heat Recovery Systems: An alternative to produce renewable heat and promoting ecosystem services. (Elsevier, Ed.) Environmental Challenges(4), p. 100131.
DOI 10.1016/j.envc.2021.100131

Mason, I. G. (2006). Mathematical modelling of the composting process: a review. Waste Management, 26(1), 3-21.
DOI 10.1016/j.wasman.2005.01.021

Mason, I. G. (2007). A Study of Power, Kinetics, and Modelling in the Composting Proces. Christchurch, New Zealand: University of Canterbury.
DOI 10.26021/2348

Mudhoo, A., & Mohee, R. (2008). Modeling Heat Loss during Self-Heating Composting Based on Combined Fluid Film Theory and Boundary Layer Concepts. Journal of Environmental informatics, 11(2)

Müller, N. (2017). Untersuchungen zum Betreibsverhalten von Biomeilern. Dresden: Technische Universität Dresden.

Mwape, M. C., Muchilwa, I. E., Siagi, Z. O., & Yamba, F. D. (2020). Design and Performance Evaluation of a Hydronic Type Compost Heat Exchanger. Cogent Engineering, 7(1), 1846253.
DOI 10.1080/23311916.2020.1846253

Nwanze, K., & Clark, O. (2019). Optimizing Heat Extraction from Compost. Compost Science and Utilization, 27(4), 217-226.

Rongfei, Z., Huiqing, G., & Wei, G. (2017). Comprehensive review of models and methods used for heat recovery from composting process. International Journal of Agricultural and Biological Engineering, 10(4), 1-12.
DOI 10.25165/j.ijabe.20171004.2292

Schmidt-Baum, T., Jaschke, N., Stinner, W., Schmidt, D., Windisch, F., Renner, D., & Pohl, R. (2020). IBÖM03: Entwicklung eines Mehrkammerbiomeilers zur effizienten Wärme und Komposterzeugung. Leipzig: DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH.
DOI 10.2314/KXP:176596945X

Sidhu, H. S., Nelson, M. I., & Chen, X. D. (2006). A simple spatial model for self-heating compost piles. ANZIAM Journal, 48, 135-150.
DOI 10.21914/anziamj.v48i0.86

Sidhu, H., Nelson, M. I., Luangwilai, T., & Chen, X. D. (2007). Mathematical modelling of the self-heating process in compost piles. Chemical Product and Process Modeling, 2(2), 8.
DOI 10.2202/1934-2659.1070

Thermal protection and energy economy in buildings - Part 6: Calculation of annual heat and energy use. (2003-01). German Institute for Standardisation.
DOI 10.31030/9258155

Vidriales-Escobar, G., Rentería-Tamayo, R., Alatriste-Mondragón, F., & González-Ortega, O. (2017). Mathematical modeling of a composting process in a small-scale tubular bioreactor. Chemical Engineering Research and Design, I(20), 360-371.
DOI 10.1016/j.cherd.2017.02.006

Wikipedia. (2019, 01 18). Retrieved from Wikipedia:

Wikipedia. (2019, 01 18). Retrieved from

Yu, S. (2007). Heat and mass transfer in passively aerated compost. PhD thesis, University of Alberta, Alberta.
DOI 10.7939/r3-xd82-bk03

Zambra, C. E., Moraga, N. O., & Escudey, M. (2011). Heat and mass transfer in unsaturated porous media: Moisture effects in compost piles self-heating. International Journal of Heat and Mass Transfer, 54(13-14), 2801-2810.
DOI 10.1016/j.ijheatmasstransfer.2011.01.031

Zambra, C. E., Moraga, N. O., Rosales, C., & Lictevout, E. (2012). Unsteady 3D heat and mass transfer diffusion coupled with turbulent forced convection for compost piles with chemical and biological reactions. International Journal of Heat and Mass Transfer, 55(23-24), 6695-6704.
DOI 10.1016/j.ijheatmasstransfer.2012.06.078

Zampieri, P. (2017). Modelling of a technology for heat recovery from the composting process. Milan: Politecnico di Milano. Retrieved from