[home] [Personal Program] [Help]

---

Session: Poster Session and Sponsors Exhibition
Session starts: Thursday 22 September, 14:00

---

Guoquan Qiu (University of Nottingham)
Gang Pei (University of Nottingham & Univ. of Sci.and Technol. of China)

Abstract:
Biomass-fired or solar-driven micro-scale combined heat and power (micro-CHP) systems with organic Rankine cycle (ORC) have been highly concerned in the latest decade because the electric output (1-10kWe) and the heat output (20-50kWth) generated by the micro-CHP system are very applicable for a household or a little enterprise. The ORC-based micro-CHP system mainly consists of a heat source (e.g. a biomass boiler, solar collectors), an evaporator, an ORC expander, an alternator, a heat recuperator and a condenser. The expander plays a vital role in the ORC-based micro-CHP system; however the lack of commercially available micro-scale expanders (rated 1-10kW) applicable to ORC-based micro-CHP systems has hindered the development of these novel CHP systems. Qiu [1] reviewed various state-of-the-art kinds of micro-scale expander and concluded that scroll expanders and vane expanders are likely the good choices for 1-10 kWe micro-CHP systems. The vane expanders modified from air motors have been applied by Qiu [2]. The micro-CHP system with a 50kWth biomass-pellet boiler can generate 937W electricity (12.52VDC and 74.86ADC) and 47kWth heat which are more or less sufficient to meet the domestic electrical and heating demands [2]. The vane expanders modified from air motors may be feasible in both economic sector and technical sector. Compared with other kinds of expanders, the rotary vane expanders have simpler structure, easier manufacturing and thus lower cost [3]. Air motors are designed to replace electric motors and applied in special spark-prohibited environments [4], accordingly leaking of the air motor-modified vane expanders with ORC fluids is inevitable since they are subject to sealing problems over the big variations of temperature and pressure with the ORC. The leaking may be avoided after the sealant is applicable for the working ORC fluid and the casing of the rotor is designed with less bolt fixing (leaking occurs along the bolts or sealants). So specific mechanical designs and sealing skills may be developed to manufacture the vane expanders with ORC fluids, which should be feasible in technology. This paper presents some leaking problems occurring in applying air motor-modified vane expander and some methods of solving leaking problems. Vane expanders are feasible for ORC-based micro-CHP systems. REFERENCES [1] G. Qiu, H. Liu and S.B.Riffat, “Expander for micro-CHP systems with organic Rankine cycle”, Applied Thermal Engineering, DOI:10.1016/j.applthermaleng.2011.06.008. (Accepted) [2] H. Liu, G. Qiu, Y. Shao, F. Daminabo and S.B. Riffat, “Preliminary experimental investigations of a biomass-fired micro-scale CHP with organice Rankine cycle”, Intl J. of Low-Carbon Technol. Vol. 5, pp.81-87, (2010). [3] B. Yang, X. Peng, Z. He, B. Guo and Z. Xing,“Experimental investigation on the internal working process of a CO2 rotary vane expander”, Applied Thermal Engineering, Vol. 29, pp.2289-2296, (2009). [4] Y.R. Hwang, Y.T. Shen and M.S. Chen, “Dynamic analysis and fuzzy logic control for the vane-type air motor”, J. of Mech. Sci. and Technol. Vol. 23,pp.3232-3238, (2009).