Search results for "Rating"
showing 10 items of 2021 documents
Absorption equipment for energy savings: A case study in Sicily
2013
Abstract This paper considers a feasibility study on the recovery of the reject heat available from an electric utility with two units operating with 120-MW gas turbines; these units have a heat recovery system that feeds the district heating pipeline of an industrial consortium. Thus, feeding the expeller of the absorption equipment installed in a cooling plant for foodstuff stocking represents an opportunity for the feasibility study. This plant operates at both 0 °C and −18 °C. The feasibility study covers two aspects: (1) the technical feasibility of a suitable absorption cooling plant that uses two separate pieces of absorption equipment working with the pair ammonia–water and (2) the …
Experimental EMF characterization of a secondary substation
2015
This paper presents the results of the experimental EMC characterization of a new medium/low voltage (MV/LV) secondary substation, which was developed in the framework of the research project "NEW CAB ELARC". It has two MV/LV transformers, with total rated power of 1000 kVA. To perform the experimental characterization, firstly an analysis was performed of the Italian and European standards recommendations. Different approaches were highlighted and the most appropriate procedures were identified for the measurement of the magnetic fields emissions, at power systems frequency (50 Hz) in steady-state conditions. A dedicated test lab was set up for the secondary substation characterization. Th…
Oil filled MV/LV Power Transformer Behavior in Narrow Band Power Line Communication Systems
2012
The aim of this paper is to characterize oil-filled power transformers in the narrow-band power-line communication (PLC) frequency range of 50-150 kHz. A new model is proposed for such type of a transformer, in the aforementioned frequency range of interest, in order to study its influence on the signal transmission and to investigate the possibility that the PLC signal can cross the power transformer itself. The new model is simpler than those previously proposed in literature, and it can be used in the whole frequency range available for NB PLC according to the CENELEC EN 50065-1 A-band. In order to validate the model, simulation and measurement results are compared for four oil-filled po…
A novel hybrid polygeneration system supplying energy and desalinated water by renewable sources in Pantelleria Island
2017
Abstract In this paper a thermoeconomic analysis of a novel hybrid Renewable Polygeneration System connected to a district heating and cooling network is presented. The plant is powered simultaneously by solar and geothermal sources, producing electricity, desalinated water, heat and cooling energy. System layout includes Parabolic Through Collector (PTC) field, geothermal wells, Organic Rankine Cycle (ORC) unit and a Multi-Effect Desalination (MED) system. Cooling and thermal demands are calculated by suitable building dynamic simulation models, calibrated for Pantelleria Island. Electrical demand is obtained by measured data. A detailed control strategy has been implemented in order to pr…
Manufacturing tolerances effects on PV array energy production
2014
This paper investigates the tolerance effects of commercial photovoltaic modules in terms of electrical energy reduction of photovoltaic plants. Several commercial modules, having the same rated power, present different power tolerance values. A wide tolerance is an indicator of possible defects or differences in the production process and is responsible of remarkable reductions in the electricity production of photovoltaic plants. In this paper, thanks to the development of a suitable simulation tool, several simulations have been carried out, considering different tolerance and shading conditions for the PV array. Simulation results quantify the peak power value of the different plant con…
On the effects of HV/MV stations on global grounding systems
2016
The METERGLOB project has faced the issue of the identification of Global Grounding Systems. One of the main point of the problem is to define if an interconnection of single grounding systems gives place to a Global Grounding System in any condition and for every kind of ground fault. This paper focuses the attention on what happens in the case of single line to ground fault inside a HV/MV station whose ground electrode is connected to the cable' shields of the MV lines outgoing the station and supplying the secondary substations of a given area.
Economic analysis on dynamic photovoltaic systems in new Italian “feed in tariffs” context
2013
Dynamic photovoltaic generators, based on the application of solar-trackers, are able to give an increment to the electric energy production from solar source. Their realization and maintenance costs are certainly higher than those of fixed ones. In this paper the Authors propose a method to estimate the increment of electrical energy generation that must be guaranteed by a dynamic photovoltaic generator, so as its realization could be more favorable with respect to that of a fixed generator one with the same rated power. This method, developed by means of classical economic indexes like the Pay-Back-Period and the Net Present Value, takes in to account the economic incentives for the PV sy…
Analysis of Air Cycle and Efficiency Evaluation for a Blast Freezing Tunnel Plant
2013
Air refrigerating systems offer a suitable alternative to vapour compression systems. Air can be used as working fluid in gas compression cycles for refrigeration, air conditioning and heat pump systems. This paper gives some results of theoretical investigation into improved air cycles for refrigeration systems and a comparison is made with their performances. The case-study relates to a dual purpose refrigerating plant. A blast freezing tunnel gives the coldest air stream and, in cascade, the air coming out from the tunnel is used in a channel network for feeding a lot of chilling cells. The case-study analysed indicates that there is a real possibility to build plants which will be equip…
An NTC zone compliant knock onset prediction model for spark ignition engines
2015
Abstract Pollutant emissions reduction and energy saving policies increased the production of Spark Ignition (SI) engines operated with gaseous fuels. Natural Gas (NG) and Liquefied Petroleum Gas (LPG), thanks to their low cost and low environmental impact represent the best alternative. Bi-fuel engines, which may run either with gasoline or with gas (NG or LPG), widely spread in many countries thanks to their versatility, high efficiency and low pollutant emissions: gas fueled vehicles, as example, are allowed to run in many limited traffic zones. In the last years, supercharged SI engines fueled with either gasoline or gaseous fuel, spread in the market. Thermodynamic simulations, widely …
Performances Comparison for a Rotating Shaft Suspended by 4-Axis Radial Active Magnetic Bearings via 𝜇 -Synthesis, Loop-Shaping Design, and Sub ( 𝐻…
2011
The control systems applied on active magnetic bearing are several. A perfect levitation is characterized by maintaining the operating point condition that is characterized by the center of stator coincident with the geometric center of shaft. The first controller implemented for this purpose is PID controller that is characterized by an algorithm that leads the amplifier to produce control current until the operating point condition is not reached, this is obtained by an integration operator. The effect of an integrator is essential but not necessary for a centered levitation for example in the robust control characterized by a dynamic model depended on plant of system so that it depends o…