Robert Zanelli's scientific contributions
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Publications (8)
This paper presents the analysis of an original design of small hybrid solar plant using Organic Rankine Cycles with hermetic scroll expander- generators. The hot supply is provided from vacuumed collector tubes along the focal line of solar concentrators made of mirror bands fixed on a plane surface (CEP). The plant is integrated with a cogenerati...
This paper describes a 1 to 3.5 kWe hermetic scroll expander generator modified from a standard hermetic compressor, an organic Rankine cycle test facility built to test expanders up to 10 kWe and a set of experimental results using HFC 134a in the dry vapor domain. Peak overall isentropic efficiencies in the range of 63 to 65% for speeds of rotati...
This paper discusses the choice and implementation of bearings for oil-free compressors where the system refrigerant is used as the lubricant in externally pressurised and hybrid bearings. The problems of oil contamination in heat pump application is described followed by methods to produce genuine oil-free hermetic systems. Alternative bearing cho...
Citations
... The structure of the cycle has a single volumetric turbine stage involving an organic fluid with the high temperature kept constant while the lower temperature is variable. The condensation of the organic fluid does not take place at ambient temperature but at a temperature higher than that required by the absorption machine [1,3,4,5] and it is also subject to the average ∆ ℎ . The efficiency can be expressed by the following model where parameters and 1 are determined experimentally. ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/272436818083846-1441965407246_Q64/Daniel-Favrat.jpg)
... The major difficulty of this system is to be able to adequately synchronize the two scrolls while keeping tight clearances to reduce internal leakage. This complexity ended researches [3] about this concept in the 90s. Indeed, the complexity of the mechanism, the precision required for the machining of certain parts and the greater number of parts made the concept less attractive than traditional orbital scroll compressors. ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/272395143479307-1441955471367_Q64/Yves-Perriard.jpg)
... In a study by Moleneaux, hybrid bearing was found to be more suitable as ORC bearing compared to steel bearing (Molyneaux & Zanelli, 1996). The application of hybrid bearing for refrigerant has also been suggested by Jacobson as hybrid bearing shows an optimization of raceway topography to ensure a maximum elastic deformation of the asperities in the Hertzian contact compared to steel bearing (Jacobson & Espejel, 2006). ...
... Wet fluid is usually incompatible with ORC systems; the accumulation of liquid droplets on the turbine blade causes erosion, so it must be superheated. The volumetric expander, on the other hand [24,25], at the inlet taking a high liquid fraction such as screw expander and scroll expander, shows the advantage which allows the design of "wet" cycles [24,26]. To put it another way, wet fluid is projected to be a propitious fluid for ORCs that do not require superheating. ...
