Towards thermal design optimization of tubular digesters in cold climates: a heat transfer model.

A cold climate, low cost, tubular digester is monitored and temperatures from different parts of the slurry, greenhouse, and adobe walls are presented, discussing the thermal performance of the digester. The slurry exhibits a vertical gradient of 6°C, with a mean value of 24.5°C, while the ambient temperature varies from 10°C to 30°C, showing the efficiency of the system as a solar heat collector with thermal inertia. A simple time-dependent thermal model is developed using inputs of solar radiation, wind velocity, ambient temperature, and digester geometry. The model outputs include temperatures of the slurry, the biogas, its holding membrane and the greenhouse air, wall and cover. Radiative, convective and conductive heat transfer phenomena are considered between all system elements. The model has 0.47°C (2%) standard error for the average slurry temperature. This model can be used to predict the influence of geometry and materials on the performance of the digester.

[1]  Energía, participación y sostenibilidad , 2006 .

[2]  P. P. S. Gusain,et al.  Renewable energy in India. , 1990 .

[3]  S. C. Bhattacharya,et al.  Renewable energy in India: Historical developments and prospects , 2009 .

[4]  G.P.A. Bot,et al.  Design of A Solar Thermophilic Anaerobic Reactor for Small Farms , 2004 .

[5]  D. L. Nofziger,et al.  Incorporating Temperature Effects on Pesticide Degradation into a Management Model , 1999 .

[6]  Petros Axaopoulos,et al.  Simulation and experimental performance of a solar-heated anaerobic digester , 2001 .

[7]  N. K. Bansal,et al.  Heat loss reduction from the gas holder/fixed gas dome of a community‐size biogas plant , 1985 .

[8]  J. R. Philip.  Environmental Soil Physics, by D. Hillel, Academic Press, San Diego, CA, xxvii+771 pp., ISBN 0-12-348.525-8, ($69.95) , 1999 .

[9]  J. L. Torres,et al.  Comparative study of various models in estimating hourly diffuse solar irradiance , 2010 .

[10]  John Boland,et al.  Modelling of diffuse solar fraction with multiple predictors , 2010 .

[11]  W. Beckman,et al.  Solar Engineering of Thermal Processes , 1985 .

[12]  Aprovechamiento energético de la biomasa , 2006 .

[13]  V.V.N. Kishore,et al.  A heat-transfer analysis of fixed-dome biogas plants , 1989 .

[14]  Thibault Perrigault.  Mejoramiento del comportamiento térmico de un biodigestor low-cost tipo plug-flow , 2010 .

[15]  D. A Stafford,et al.  Anaerobic digestion : proceedings of the First International Symposium on Anaerobic Digestion held at University College, Cardiff, Wales, September 1979 , 1980 .

[16]  Sunil Herat,et al.  Biogas as a sustainable energy source in Nepal: Present status and future challenges , 2009 .

[17]  Bin Chen,et al.  Rural energy in China: pattern and policy. , 2009 .

[18]  W. Swinbank.  Long‐wave radiation from clear skies , 1963 .

[19]  Huang Liming,et al.  Financing rural renewable energy: A comparison between China and India , 2009 .

[20]  B Mattiasson,et al.  EFFECT OF TEMPERATURE DECREASE ON THE MICROBIAL POPULATION AND PROCESS PERFORMANCE OF A MESOPHILIC ANAEROBIC BIOREACTOR , 2007, Environmental technology.

[21]  Lluís Batet Miracle,et al.  Adaptación de biodigestores tubulares de plástico a climas fríos , 2009 .

[22]  J. A. Usmani,et al.  PERFORMANCE CHARACTERISTIC OF A GREENHOUSE INTEGRATED BIOGAS SYSTEM , 1996 .

[23]  F. Dolberg,et al.  On-farm work with low cost tubular plastic biodigesters for resource-poor farmers in Tanzania. , 1995 .

[24]  J. Herrero,et al.  Transfer of low-cost plastic biodigester technology at household level in Bolivia. , 2007 .

[25]  Curt Gooch,et al.  HEAT TRANSFER MODEL FOR PLUG-FLOW ANAEROBIC DIGESTERS , 2005 .

[26]  Gunnar Lidén,et al.  The effect of temperature variation on biomethanation at high altitude. , 2008, Bioresource technology.

[27]  Jay F. Martin,et al.  Methane production in low-cost, unheated, plug-flow digesters treating swine manure and used cooking grease. , 2010, Bioresource technology.

[28]  Laia Ferrer-Martí,et al.  Codigestion of cow and guinea pig manure in low-cost tubular digesters at high altitude. , 2011 .

[29]  J. Martí-Herrero.  Reduced hydraulic retention times in low-cost tubular digesters: Two issues , 2011 .

[30]  Huang Ning-sheng,et al.  Popularizing household-scale biogas digesters for rural sustainable energy development and greenhouse gas mitigation , 2008 .

[31]  Daniel Hillel,et al.  Introduction to soil physics , 1982 .

[32]  J Martí-Herrero,et al.  Design methodology for low cost tubular digesters. , 2012, Bioresource technology.

[33]  I. Ferrer,et al.  Biogas production in low-cost household digesters at the Peruvian Andes , 2011 .

[34]  Frank P. Incropera,et al.  Fundamentals of Heat and Mass Transfer , 1981 .

[35]  J. Marti ´ Herrero.  Reduced hydraulic retention times in low-cost tubular digesters: Two issues , 2011 .