Expanders for micro-CHP systems with organic Rankine cycle

Abstract

ABSTRACT:The continual increases in global energy demand and greenhouse gas emissions call for more and more utilisation of sustainable energy sources, such as solar energy, biomass energy, and waste heat. Solar thermal energy, the heat of biomass combustion and waste heat may be used to drive a combined heat and power (CHP) system.In recent years, several micro-CHP systems with organic Rankine cycle (ORC) suitable for domestic applications (1-10kW e ) driven by solar thermal, biomass-fired boilers and waste heat resources have been investigated. These ORC-based micro-CHP systems have lower operation pressures and temperatures compared to conventional steam-Rankine cycle CHP systems and hence safer for household applications. However, the lack of commercially available expanders applicable to ORC-based micro-CHP systems has hindered the development of these novel CHP systems. This paper summarizes the findings of the market research for the expanders and discusses the selection and choices of the expanders for ORCbased micro-CHP systems. The working principles and the characteristics of several kinds of expanders, including turbine expanders (i.e., turboexpander), screw expanders, scroll expanders and vane expanders, are introduced and evaluated.

Design and experimental investigation of the cogenerative domestic micro power plant with ORC system

“…Przegląd różnych typów ekspanderów, głównie o mocy do 10 kWel, rozwijanych obecnie przez ośrodki przemysłowe i naukowe, został zamieszczony np. w pracy [2]. Żaden z omawianych ekspanderów nie jest jeszcze gotowy do produkcji seryjnej i sprzedaży na większą skalę.…”

Small Scale Organic Rankine Cycle (ORC): A Techno-Economic Review

“…Literature reviews on small-scale expanders propose different configurations [86]. The options available present both pros and cons that complicate the selection of a single "ideal" expander.…”

“…• Freezing point: The freezing point needs to be well below the minimum ambient temperature in the site in which the system is installed, to avoid solidification of the working fluid during periods of inactivity of the ORC plant [85]. • Cycle top pressure: It is important to keep the cycle top pressure well below the fluid critical pressure [86]. This is necessary to prevent the formation of liquid droplets during the expansion process and to overcome instability during vaporization.…”

Effect of resistive load on the performance of an organic Rankine cycle with a scroll expander

“…Qiu et al [11] evaluated several expansion devices for micro-CHP ORC systems including turbine, scroll, screw and vane expanders, and suggested that both scroll and vane expanders are suitable for micro-scale ORC systems with capacity ranging from 1kW to 10kW. Ali Tarique et al [12] stated that a scroll expander is the best choice for small capacities due to the more flexible operation characteristic.…”