Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Agricultural and Biosystems Engineering

First Advisor

Stephen J. Marley


An investigation was conducted to determine the performance characteristics of an integrated biofueled boiler energy system for space heating for farmstead applications. The integrated energy system has been recently installed at Iowa State University's McNay Memorial Research Center. The project was initiated to provide information to Iowa farmers and small industries concerning the operation of wood-fired energy systems and the management of domestic energy resources for potential substitution for imported heating energy. The McNay energy system includes the various processes required to convert wood energy on the ground to energy at point of actual use for space heating;Optimum operating conditions for maximum boiler system performance were determined experimentally by employing quadratic central composite design. The three independent variables such as primary air damper (PAD) opening, Secondary air damper (SAD), and depth of fuel bed (DFB) were varied to determine their effect on the wood-fired boiler system efficiency. A total of 20 performance tests were conducted. The seasonal thermal energy delivered for space heating in a farm house and farm workshop was monitored by employing energy measuring instruments and a data acquisition system;Under optimum operating conditions, the boiler system efficiency was found to be 54% while burning green wood chips at 45% moisture on a wet basis. The total seasonal thermal energy delivered for space heating for the farmstead application was 60,836 KWh (219 GJ), and the boiler consumed 60.5 metric tons of green wood chips during the winter season of three and a half months from December 16, 1989 to March 31, 1990;The analysis of energy cost of the wood energy system using net energy analysis and life cycle economic cost analysis showed that the wood energy system has the potential to be competitive with a fossil based system by improving system efficiency and reducing wood harvesting and handling costs.



Digital Repository @ Iowa State University,

Copyright Owner

Amjad Pervez Chaudhary



Proquest ID


File Format


File Size

251 pages