Experimental tests of the prototypical micro-cogeneration system with a 100 kW biomass-fired boiler

Abstract

Renewable energy based micro cogeneration systems are an interesting option for domestic, agricultural and commercial sectors. In this paper, a dedicated system with a 100 kWth biomass-fired boiler was proposed. Developed system works according to modified Rankine Cycle operation. Steam generated in two shell and tube heat exchangers is used to power steam engine (connected with power generator) and then flows via condenser to degasifier. During the presented tests, the selected parameters of the boiler, oil circuit and steam/condensate circuit were analyzed. As was shown, the maximum thermal power taken from the oil circuit to evaporate condensate and superheat steam was ~105 kWth (it was ~91% of thermal power generated in the boiler). The value steam pressure varied from 2 to 5 bars during operation of the steam engine. Steam mass flow was then equal to ~105 kg/h, what allowed to generate electric power at a level of ~1.05 kWel. Such a low value resulted e.g. from limitations in the oil temperature, limitations in the steam temperature, steam pressure and steam flow, limitations caused by power generator’s construction, as well as other construction and operating parameters.