Expansion machine for a low power-output steam Rankine-cycle engine

Badr, O.; Naik, S.; O’Callaghan, Paul; Probert, S.D.

doi:10.1016/0306-2619(91)90024-r

Cited by 63 publications

(43 citation statements)

References 6 publications

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“…For a low power-output system (<1 kW) such as this, positive-displacement expanders may be favoured over turbomachines (as discussed Section 1.2). Thus, for all simulations, an isentropic efficiency of 75% is used which is typical of those reported for small-scale positive-displacement machines [10,25,[30][31][32][33][34][35]. The pressure at the expander exit is set to be equal to the saturation pressure at State 1 (see Section 2.2.3).…”

Section: Orc Expandermentioning

confidence: 99%

An assessment of solar-powered organic Rankine cycle systems for combined heating and power in UK domestic applications

2015

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h i g h l i g h t sA domestic-scale combined solar heat and power (CSHP) system is simulated in the UK climate. The CSHP system comprises a solar collector array, an ORC engine and a hot-water cylinder. An exergy analysis, parametric study and annual performance assessment are performed. An average electrical power of 89 W plus an 86% hot water coverage are demonstrated. A total system cost as low as £2700 and a levelised cost electricity of 44 p/kW h are reported. a b s t r a c t Performance calculations are presented for a small-scale combined solar heat and power (CSHP) system based on an Organic Rankine Cycle (ORC), in order to investigate the potential of this technology for the combined provision of heating and power for domestic use in the UK. The system consists of a solar collector array of total area equivalent to that available on the roof of a typical UK home, an ORC engine featuring a generalised positive-displacement expander and a water-cooled condenser, and a hot water storage cylinder. Preheated water from the condenser is sent to the domestic hot water cylinder, which can also receive an indirect heating contribution from the solar collector. Annual simulations of the system are performed. The electrical power output from concentrating parabolic-trough (PTC) and non-concentrating evacuated-tube (ETC) collectors of the same total array area are compared. A parametric analysis and a life-cycle cost analysis are also performed, and the annual performance of the system is evaluated according to the total electrical power output and cost per unit generating capacity. A best-case average electrical power output of 89 W (total of 776 kW h/year) plus a hot water provision capacity equivalent to $80% of the total demand are demonstrated, for a whole system capital cost of £2700-£3900. Tracking PTCs are found to be very similar in performance to non-tracking ETCs with an average power output of 89 W (776 kW h/year) vs. 80 W (701 kW h/year).

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Section: Orc Expandermentioning

confidence: 99%

An assessment of solar-powered organic Rankine cycle systems for combined heating and power in UK domestic applications

2015

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“…Available options of volumetric expanders include reciprocating and rotary expanders, but this last solution, which is often based on the Wankel concept [2,4], shows implementation difficulties [1], while reciprocating SEs result in an easier design and construction [5].…”

Section: Introductionmentioning

confidence: 99%

“…The use of small-scale Water Steam RCs that are characterised by a small steam flow rate, shifts the expander technology from turbomachines towards volumetric machines [2], since some of the major problems of using turbines as expanders in small-scale RCs are their very low efficiency, high production costs, especially for multistage turbines, and the possibility of a rapid erosion of the turbine's blades due to the moisture content in the expanding steam [3].…”

Section: Introductionmentioning

confidence: 99%

Preliminary design and controlling strategies of a small-scale wood waste Rankine Cycle (RC) with a reciprocating steam engine (SE)

Badami

Mura

2009

Energy

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“…Of the positive-displacement expanders, common designs include rotary-vane expanders with reported isentropic efficiencies that range from 25% to 35% [9], helical screw expanders with reported isentropic efficiencies that range from 30% to 85% [9,10], and scroll expanders with reported isentropic efficiencies that range from 30% to 70% [11]. The research performed in this investigation pertains to quantitatively understanding the performance of a novel form of expander.…”

Section: Introductionmentioning

confidence: 99%

Naturally-Forced Slug Flow Expander for Application in a Waste-Heat Recovery Cycle

Witt

Hugo

2014

Energies

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This paper investigates a slug-flow expander (SFE) for conversion of high-pressure gas/vapor into kinetic energy of liquid slugs.The energy transfer from high-pressure to kinetic energy is quantified using thrust plate measurements. Non-dimensional thrust data is used to quantify performance by normalizing measured thrust by thrust for the same water flow rate at zero air flow rate. A total of 13 expander configurations are investigated and geometries with the shortest cavity length and the smallest exit diameter are found to result in the largest non-dimensional thrust increase. Results show that thrust augmentation increases with the initiation of slug flow in the SFE. The analysis performed on the normalized thrust readings suggested that as the water and air flow were increased to critical conditions, the liquid slugs produced by the SFE augmented the thrust measurements. The final performance evaluation was based on linear regression of the normalized thrust measurements where slug flow was generated for each SFE architecture. Greater magnitudes of the slope from the linear regression indicated the propensity of the SFE to augment thrust. This analysis confirmed that for the SFE configurations over the range of values investigated, the SFE increased thrust up to three times its original value at no air flow. Given the inherent multiphase nature of the slug-flow expander, application to systems involving expansion of wetting fluids (water as part of a waste-heat recovery system) or air with water droplet formation (as part of a compressed-air energy storage system) could be considered.

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Expansion machine for a low power-output steam Rankine-cycle engine

Cited by 63 publications

References 6 publications

An assessment of solar-powered organic Rankine cycle systems for combined heating and power in UK domestic applications

An assessment of solar-powered organic Rankine cycle systems for combined heating and power in UK domestic applications

Preliminary design and controlling strategies of a small-scale wood waste Rankine Cycle (RC) with a reciprocating steam engine (SE)

Naturally-Forced Slug Flow Expander for Application in a Waste-Heat Recovery Cycle

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