Solar thermal power plants have been widely studied in recent years as solar energy is clean, affordable and largely available. The possibility of converting into electricity with small scale (lower than 10 kWe) Organic Rankine Cycle (ORC) operating at low temperature 130 °C), seems today a viable option. In this paper, the design development prototypal ORC plant (< presented. ORC, equipped scroll expander installed Florence, Italy, powered by parabolic trough collectors (PTC) collector...

The paper presents the results of a research regarding application cogeneration plants, based on organic rankine cycle (ORC), fed with wood residuals. In first part an energy audit companies in furniture industry district, located North-East Italy, is presented. On basis these data typical electricity/thermal demand profile dependent number employees has been determined. order to evaluate potential savings achievable ORC plant, numerical simulation model developed analyse balances components...

The upcoming stricter limitations on both pollutant and greenhouse gases emissions represent a challenge for the shipping sector. entire ship design process requires an approach to innovation, with particular focus fuel choice power generation system. Among possible alternatives, natural gas hydrogen based propulsion systems seem be promising in medium long term. Nonetheless, storage still represents problem terms of cargo volume reduction. This paper focuses issue, considering compressed...

This paper reports the results of an extensive study concerning surge instability in industrial compression system and its dynamic suppression. Both numerical simulations experiments have been used to analyse behaviour under unstable operating conditions compare different control devices for First, characterization is performed over whole range a based on four-stage centrifugal compressor. The unsteady energy associated with cycle employed as index intensity allow quantitative approach...

This paper describes, from a theoretical point of view, the behavior compression systems during surge and effect passive active control devices on instability limit system. A lumped parameter model is used to simulate system described in Part I this work (Arnulfi et al., 1999), based an industrial multistage centrifugal compressor. comparison with experimental results shows that accurate enough describe quantitatively all features phenomenon. movable wall studied order suppress Passive...

In the last years one of main research topics in energy field is represented by Organic Rankine Cycles (ORCs), due to their applicability recovery from waste heat and distributed combined power (CHP) generation, particularly small micro scale systems. One key devices cycle expander: it must have a limited cost (like all other components, order ensure economic feasibility), but also high efficiency, since temperature source often low then efficiency inherently scarce. first part this paper...

This paper describes, from a theoretical point of view, the behaviour compression systems during surge and effect passive active control devices on instability limit system. A lumped parameter model is used to simulate system described in Part I this work (Arnulfi et al., 1998), based an industrial multistage centrifugal compressor. comparison with experimental results shows that accurate enough describe quantitatively all features phenomenon. moveable wall studied order suppress Passive...

This paper reports an experimental investigation on centrifugal compressor surge. The compression system consists of a four-stage blower with vaned diffusers and large plenum discharging into the atmosphere through throttle valve. Measurements unsteady pressure flow rate in plant, instantaneous velocity first fourth stage, are performed during deep surge, at several valve settings three different rotation speeds. Additional tests have been carried out configuration, i.e., without plenum,...

The present paper reports a numerical–experimental study on the dynamic behavior of compression system based multistage centrifugal blower and fitted with an innovative device for suppression surge instability. control is passive type aeroelastic coupling basic hydraulic oscillator. controlled modeled at first by using nonlinear lumped parameter approach. simulated dynamics within wide range operating conditions allows parametric analysis to be performed optimal values parameters singled...

Tackling the climate change by reducing energy consumption is among biggest, most urgent challenges society facing and requires a continuous efficiency improvement of thermal systems. Appropriate design strategies, developed priori then experimentally validated according to suitable test protocols on prototype, are needed in order reach potential saving targets. These strategies can successfully be implemented food service sector, where cooking appliances, particular, present many...

Cavitation is a phenomenon characterised by the presence of vapour bubbles in fluid led local drop pressure. In literature it well known impact on cavitation pressure and temperature pure water, but there are only few studies analysing how certain components detergents additives can influence phenomenon. The could be explained modified viscosity rheology solution also variation tension. Most these effects due to surfactants polymers solution. dynamic pumps an important aspect that needs...

This paper reports an experimental investigation on centrifugal compressor surge. The compression system consists of a four-stage blower with vaned diffusers and large plenum discharging into the atmosphere through throttle valve. Measurements unsteady pressure flow rate in plant, instantaneous velocity first fourth stage are performed during deep surge, at several valve settings three different rotation speeds. Additional tests have been carried out configuration, i.e., without plenum,...

Natural gas is becoming increasingly important to meet the growing demand for energy, guaranteeing a reduction in polluting emissions. Transportation form of Compressed Gas (CNG) could be an alternative traditional transportation by pipeline or, as liquefied gas, ships, but ratio between mass transported and container weight currently too low. One many projects focusing on development innovative lightweight pressure cylinders GASVESSEL, which proposes composite with diameter more than 3 m:...

The paper presents the model of a combined heat and power (CHP) unit, based on variable speed internal combustion engine (ICE) interfaced with photovoltaic (PV) system. This is validated by means experimental data obtained an 85 kWe CHP unit fueled natural gas PV system rated 17.9 kW. Starting from daily load profiles, applied to investigate primary energy saving (PES) integrated + in several operating conditions for different sizes array. results demonstrate dependence performance mode...

The present paper considers the suppression of surge instability in compression systems by means active control strategies based on a high-gain approach. A proper sensor-actuator pair and proportional controller are selected which, theory, guarantee system stabilization any operating condition for sufficiently high value gain. Furthermore, an adaptive strategy is introduced which allows to automatically detect suitable gain needed stabilization, without requiring knowledge compressor plant...

An automatic approach for the multi-objective shape optimization of microgas turbine heat exchangers is presented. According to concept multidisciplinary optimization, methodology integrates a CAD parametric model transfer surfaces, three-dimensional meshing tool, and CFD solver, all managed by design platform. The repetitive pattern surface geometry has been exploited reduce computational domain size, constant flux boundary conditions have imposed better suit real operative conditions. A...