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Session: New applications: Domestic CHP
Session starts: Tuesday 08 October, 09:00
Presentation starts: 09:40
Room: Willem Burger Zaal

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Tomasz Z. Kaczmarczyk ()
Eugeniusz Ihnatowicz ()
Sebastian Bykuć ()
Grzegorz Zywica ()
Zbigniew Kozanecki ()

Abstract:
In order to meet the directives and the trends indicated by the European Union concerning the systems using renewable energy sources, in the Institute of Fluid-Flow Machinery of the Polish Academy of Sciences in Gdańsk, the idea of constructing a domestic micro power plant appeared. The first investigation of the ORC system was conducted with the use of an expansion valve simulating an expander (microturbine). In the next step, we constructed our own micro steam turbine for the domestic ORC system. The heating cycle has two heat sources that can work independently or in series. The first one is a multi-fuel boiler and the other heat source is a prototypical electric flow heater. The prototypical electric flow heater is designed to heat non-conductive fluids (thermal oil) to the temperature of about 250oC with a low power flow density and the power of 2x24 kW. The prototypical boiler enables combustion of gas fuel (town gas or gas from biomass gasification) or solid fuel in the form of biomass (pellets). The nominal boiler power in biomass combustion (pallets) is around 40 kW. The cooling system of the ORC installation performs two tasks. First, it enables cooling of the thermal oil coming to the evaporator and hence increases the range of adjustment of oil temperature. The other important task of the cooling system is quick cooling of the working medium (HFE 7100) vapour in the condenser (plate exchanger), in a way to obtain the liquid of the temperature of 65oC at the inlet of the circulating pump of the working medium. Four circulation pumps using HFE 7100 as the working fluid were analysed. Namely two commercial pumps (peripheral and gear pumps) and two prototypical pumps of our design (a pitot tube pump and a vortex pump). The ORC system cooperates with a high-speed four-stage radial microturbine whose parameters are as follows: nominal power of 3 kW, nominal rotational speed of 23 800 rpm and isentropic efficiency of about 84%. The turbine shaft is integrated with an electric energy generator and encased in a sealed housing. Given the air-tight construction and the high rotational speed, aerostatic gas bearings powered by a low-boiling medium vapour were used. The microturbine is equipped with a control and measurement system which assures good functioning of the device as well as reception and conditioning of electric energy. The paper presents the results of the experimental investigations of a regenerative ORC system using two heat sources (a multi-fuel boiler and an electric thermal oil heater), equipped with a microturbine and an expansion valve. Acknowledgements The work presented in the paper has been funded from a National Project POIG.01.01.02-00-016/08 Model agroenergy complexes as an example of distributed cogeneration based on local renewable energy sources.