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Strategies for the Design of Domestic Pellet Boilers

2018; Springer Science+Business Media; Linguagem: Inglês

10.1007/978-3-319-91334-6_91

1876-1119

Pedro Ribeiro, Cândida Vilarinho, Manuel Eduardo Ferreira, Eurico Seabra, L. Fraga, José Carlos Teixeira,

Environmental Impact and Sustainability

Domestic and industrial heating are amongst the most attractive applications for biomass as it combines high efficiency and ease-of-use. Boilers and furnaces in this range are usually of simple design and control algorithm while expected to operate over a wide range of thermal loads, typically from up 30% of the nominal load. Such constrainments often limit the overall efficiency of biomass use. In addition, from the manufacturing point of view, a product with flexibility of operation would provide a quasi-universal solution for a wide range of applications. The present paper investigates the influence of the fuel grate dimensions and the heat exchanger design on the thermal efficiency of a 25 kW pellet boiler. The prototype has a controllable independent supply of primary and secondary air and the temperature is monitored at critical locations. The continuous analysis of the flue gases for CO2, NOx, O2 and CO enabled the definition of an operation envelope that resulted in CO emissions as low as 10 ppm, using standard A1 grade pellets as fuel.