1,721,124 research outputs found
HEAT RECOVERY APPARATUS
Full text linkThe subject of the disclosed invention is a heat generator (3) for thermal energy production connected through a conveyor (4; 41, 4101, 42, 43, 4201, 4202, 4203, 4204, 4205) to one or multiple heat sources (2). The hot gases (Fl, F2) generated by said one or multiple heat sources (2) are carried through said conveyor (4) to said heat generator (3) for recovery of their enthalpy content
Apparato di recupero calore
No full textThe subject of the disclosed invention is a heat generator (3) for thermal energy production connected through a conveyor (4; 41, 4101, 42, 43, 4201, 4202, 4203, 4204, 4205) to one or multiple heat sources (2). The hot gases (Fl, F2) generated by said one or multiple heat sources (2) are carried through said conveyor (4) to said heat generator (3) for recovery of their enthalpy content
Energy versus economic effectiveness in CHP (combined heat and power) applications: Investigation on the critical role of commodities price, taxation and power grid mix efficiency
No full textStarting from PES (primary energy saving) and CSR (cost saving ratio) definitions the work pinpoints a “grey area” in which CHP (combined heat and power – cogeneration) units can operate with profit and negative PES. In this case, CHP can be profitably operated with lower efficiency with respect to separate production of electrical and thermal energy. The work defines the R-index as the ratio between the cost of fuel and electricity. The optimal value of R-index for which CHP units operate with both environmental benefit (PES > 0) and economic profitability (CSR > 0) is the reference value of electrical efficiency, ηel_ref, of separate production (national power grid mix). As a consequence, optimal R-index varies from Country to Country. The work demonstrates that the value of R corresponds to the minimum value of electrical efficiency for which any power generator operates with profit. The paper demonstrates that, with regard to the profitability of cogeneration, the ratio between the cost of commodities is more important than their absolute value so that different taxation of each commodity can be a good leverage for energy policy makers to promote high efficiency cogeneration, even in the absence of an incentive mechanism. The final part of the study presents an analysis on micro-CHP technologies payback times for different European Countries
La cogenerazione dell'industria cartaria italiana: stato dell'arte a 6 anni dallo studio Save
No full textAtti del 4O° CONGRESSO ANNUALE ATICELCA Il congresso dell’industria cartaria italiana GARDONE RIVIERA. Gardone Rivera -Toscolano, 28-29 Toscolan
apparato per autoproduzione istantanea, in una imbarcazione, di acqua dolce da dissalazione di acqua salmastra
No full textAPPARATUS FOR INDEPENDENT INSTANT PRODUCTION OF FRESHWATER FROM DESALINATION OF SEAWATER ABOARD SEAFARING CRAFT
No full textAn apparatus (1) for independent instant production, aboard seafaring craft (2), of freshwater (3) through desalination of seawater (4), combining a cogenerator (5), to produce at least electrical energy (6), which comprises a Stirling engine (7) emitting exhaust heat (8); and an inverse osmosis desalination unit (9) operatively associated with the Stirling engine (7) in such a way as to receive at least its exhaust heat (8) and to preheat with it the seawater (4) entering the desalination unit
Performance analysis of two 3.5 kWp CPV systems under real operating conditions
No full textThe paper presents the preliminary operational performance results of the of two 3.5 kWp Concentration PhotoVoltaic (CPV) devices. Each system consists of eight modules installed on a chassis for a total number of 1152 triple junction PV cells whose active area is 5.5 × 5.5 mm. The optics has a total geometrical concentration ratio of 476×. Two solutions for the primary PMMA Fresnel lens were tested, one with constant Fresnel pitch and one with variable pitch. The secondary optics is the same for both systems and consists of a truncated pyramid made of high reflective material. The two-axis tracking system is an azimuth-elevation device driven by two electrical motors and controlled by a sun sensor. Results allow to evaluate the efficiency of the plant as well as significant operational parameters under real outdoor operating conditions. The overall AC electrical efficiency is up to 31% and the power production peak is 2.54 kW. Electric power output has a linear dependency with the available Direct Normal Irradiation (DNI) while the Air Mass (AM) spectrum has a negligible effect on the performance. The system equipped with a variable pitch Fresnel lens performs slightly better (about 3.5% more power) with respect to the one with a constant pitch. The effect of lens fouling has a much higher impact: with a dirty lens the system generates over 12% less power and efficiency decreases by 3–5%, at equal solar irradiation. The performance ratio of the CPV system peaked at 82% and it has a monthly value over 70% in spring and summer months. The tracking mechanism has showed, in the worst scenario, an inaccuracy of 0.26° which is lower than the acceptance angle of the optics (0.4°)
Energy efficiency improvement in oil refineries through flare gas recovery technique to meet the emission trading targets
No full textFlare gas recovery is one of the most attractive methods to improve energy efficiency in oil refineries to decrease greenhouse gas emissions. The recovered gas is used to feed refinery processes, granting advantages in terms of fuel economy and flare stress. This paper presents the results obtained by a feasibility study of a flare gas recovery system in a real refinery; the work focused on: i) the choice and the design of the flare gas recovery system; ii) the gas treatment and reuse; iii) the economic feasibility, and the payback period. An experimental campaign has been performed to evaluate both the composition and the flow rate of the flare gas. Results showed that the flare gas had a strongly variable flow rate and composition due to the different gas species processed in refinery. A methodology for the system selection is presented: a 400 kg/h liquid ring compression device is chosen; its basic design is described as well as the chemical treatments of inert gases and hydrogen sulphide (H2S). The yearly energy recovery was estimated to be 2900 TOE, corresponding to 6600 tons of CDE (Carbon Dioxide Equivalent). Finally, an economic evaluation was carried out, showing a payback period of about 2.5 years
Effect of the Secondary Optics and the Receiver Design on the Performance of a Triple Junction Solar Cell
No full textAbstractIn this paper, the prototype of a compact and small scale HCPV system with two-axis tracking mechanism for building integration purposes is presented and the experimental measurements are reported. The system is composed of 4 groups of optics and photovoltaic cells, each containing 8 receivers. The cells are triple junction III-V (Ga0.5In0.5P, Ga0.99In0.01As and Ge) and they have a circular shape with an active area of 4.15 mm2. The optics consists of a primary and a secondary optics: the former is a PMMA square Fresnel lens (75mm – side) with constant pitch; the latter is a refractive optics (RTP) realized with dielectric material, that i) improves the light homogeneity on the cell area, ii) reduces the negative effects of the sun-tracking misalignment and iii) increases the concentration ratio. The overall geometrical concentration ratio is 1300x. The two-axis tracking system is a tip-tilt type driven by three stepper motors, one for the tip movement and the other two for the tilt movement. The alignment with the sunrays is guaranteed by an algorithm that controls the electrical motors. The HCPV prototype was tested at the Engineering Faculty of Università Politecnica delle Marche in Ancona, Central Italy. The aim of the paper is to present the performance results, both simulated and experimental, of two different secondary optics and to assess the effect of the distance between the primary and the secondary optics on the concentration efficiency. In addition, two different solutions for the 3J cell receiver where tested, the Insulated Metal Substrate technology (IMS) and the Direct Bonded Copper (DBC). The electrical I-V curves are presented in order to assess the performance of the CPV system using the two different solutions. The experimental tests are realized under real outdoor operating conditions, therefore also the direct normal radiation (DNI) was taken into account
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