Resumen: This project is part of the efforts made by Savonia University of Applied Sciences to plan the future EU-funded combustion research laboratory that will be located on Varkaus Campus (Finland). The main objective of the present thesis was to carry out an optimal design, in technical, environmental and economical terms, of a small-sized bubbling fluidized bed (BFB) boiler, which will be used mainly for research purposes. This design takes as a reference a former BFB boiler that was located at Lappeenranta University of Technology. The efforts have been focused mainly on adapting this reference design to be used for research activities and bringing construction and operating costs down. All the drawings and virtual three-dimensional models of the components have been executed using SolidWords, a computer-aided design program. The result of the design process is an efficient and environmentally friendly boiler that is going to enable numerous testing services and lines of research.