Performance Investigation of refrigerant R-407C as a Replacement to refrigerant R22 in Window Air Conditioner Unit

The present work deal with the experimental study to retrofit the refrigerant R407c with the refrigerant R22 in the air conditioning unit at an ambient temperature range between 30-45°C. The main component of the experimental rig includes a window air conditioner with a refrigeration capacity of 2 Ton refrigeration that used refrigerant R22 as a working fluid in the experimental work. The refrigerant R22 is replaced with refrigerant R407C due to similar operation properties for the two refrigerants. The experimental results displayed the refrigeration effect and coefficient of performance COP of the R22 system are high as with those of the R407C system. The falls in the evaporator and condenser for the R407C system is lower than that of the R22 system. The temperature of discharge in the compressor for the system of refrigerant R22 is greater than that of the R407C system. Moreover, condensation temperature along the tube of the condenser is decreased with the increase of the distance for both refrigerants. The refrigerant R407C may be selected as a good alternate for R22 with an agreement difference in the two refrigerants’ performance. The system did not require replacement for any part of the AC unit.

Time response of FOPID controlled PV based cascaded landsman converter-inverter fed induction motor and electric drives applications

Time Response enhancement utilizing photovoltaic based cascaded Landsman Converter (LC) structure is one of the soft strategies in the recent scenario. The prime function of a DC-DC Landsman converter is to optimize the output power of the photovoltaic array and reduce the output voltage ripples. This paper reveals the demonstration and simulation of the Cascaded Landsman Converter Inverter System (CLCIS) with a PV source. MATLAB Simulink-model for CLCIS has been created utilizing the components of Simulink and closed-loop examinations are performed with PI and Fractional-Order-PID (FOPID) Controllers. The present work deal with the comparison of transient and steady-state time responses of CLCIS with PI and FOPID controllers. The outcomes demonstrate that dynamic reaction is enhanced by utilizing FOPID controller.

Numerical Performance Investigation of Hybrid PV/Thermal System

Promoting reduction of PV temperature plays crucial role in increasing electrical performance. The present work deal with different types of absorber shape for analysing heat transfer phenomena. Serpentine and spiral absorber are using to verify this purpose with different boundary conditions of inlet mass flow rate and inlet temperatures.The recent study was conducted to evaluate the effect of some operating and designing parameters such as solar radiation levels, flow rates, absorber shape and cooling water temperature on the performance of PVT system numerically. Performance of PVT system determined by thermal efficiency, electrical efficiency and the summation of both known as total or PVT efficiency. Solar radiation ranging from 500 W/m2 to1000 W/m2 was introduced and at each, flow rates of water ranging from 0.016 kg/s to 0.05 kg/s. The results show that the performance of PVT increases with a flow rate at all radiation levels. Also the spiral flow absorber gives a higher performance than serpentine absorber where the value of of spiral absorber is increased by about 5.2% compared to the value of serpentine absorber, on the other hand, the rate of heat loss ( decreased by about 10%.Increasing initial cooling water temperature degrades electrical efficiency of PVT system.

Study of Mechanical and Wear Properties of Stir-Cast Al-Si-Cu alloy

The present work deal with an investigation of the mechanical and wear properties of eutectic Al-12.8%Si-2.5%Cu under as cast and homogenized conditions. The alloy was melted in a ceramic crucible, stirred and gravity poured into a metal mold and was then cooled under atmosphere. The stirring parameters include a stirrer speed of 400rpm at a melt temperature of 7500C for about 10 minutes. The cast specimens were homogenized in a nitrogen atmosphere crucible at a temperature of 3500C for 8 hours and furnace cooled to room temperature. The microstructure of as cast and homogenized specimen were studied under SEM. The results of SEM study showed that the Si particles were more evenly dispersed around the a-Al matrix after homogenization. This even dispersion of Si particles led to an increase in the hardness and ultimate tensile strength of the alloy. The dry sliding wear behavior was studied using a pin-on-disc machine. It is seen that the wear rate reduced with increase in sliding speed. The EDAX analysis of worn surface showed the phenomenon of lamination. It is concluded that the oxide layer formation was also a reason for increase in wear resistance of the material.

On the Origin of the Contrast Inhomogeneities Found on In0.52Al0.48As Layers Grown on InP Substrates At High Temperatures

ABSTRACTThe present work deal with the coarse contrast modulation along the <010> directions observed in (100) planar view TEM observations of In0.52Al0.48As layers grown on InP substrates at temperatures higher than 550°C. The most important features of these contrast inhomogeneites are briefly reviewed. Besides, the appearance of the contrast in [011] cross-sectioned specimens is presented and its origin related to precipitates at the layer-substrate interface. The density of precipitates (ρp) has been found to increase as Tg rises, and an approximate value of the activation energy needed to induce the precipitation has been derived from the correlation of ρp and Tg.

Inverse Inelastic Scattering Theory

For inverse scattering theories, it is well known that in order to guarrantee the existence and uniquness of the solution, drastic restrictions must be imposed on the scattering potential or on the scattering data collected from experiments (see for example Newton 1966). The existing theories in their original form such as the Geldfan Levitan or the Marehenko equations therefore cannot be used in a straightforward manner and some further steps toward simplifications have to be considered.In inelastic scattering problems where many coupled channels must be taken into account to construct various elements of the scattering matrix the problem become much more complicated both from the theoretical and experimental point of view. The present work deal only with the energy fixed case and show that a solution can nevertheless be obtained by using on one hand the conventional technique of the Abelian transformation which has been extensively applied in the JWKB approach to the one channel problem (see for example a general review by Buck 1971) with on the other some results obtained recently concerning a system of coupled differential equations (Cao 1982 1).

Doses and methods of distribution of potassium chloride on soybean crop (Glycine max (L.) Merrill) in a red latosol, affecting soil salinity, grain production and chemical composition of leaves

The present work deal t wi th an experiment under field conditions and a laboratory test of soil incubation the objectives were as follows: a. to study effects on soybean grain product ion and leaf composition of increasing doses of potassium chloride applied into the soil through two methods of distribution; b. to observe chemical modifications in the soils incubated with increasing doses of potassium chloride; and, c. to correlate field effects with chemical alterations observed in the incubation test, The field experiment was carried out in a Red Latosol (Haplustox) with soybean cultivar UFV - 1. Potassium chloride was distributed through two methods: banded (5 cm below and 5 cm aside of the seed line) and broadcasted and plowed-down. Doses used were: 0; 50; 100 and 200 kg/ha of K2O. Foliar samples were taken at flowering stage. Incubation test were made in plastic bags with 2 kg of air dried fine soil, taken from the arable layer of the field experiment, with the following doses of KC1 p,a. : 0; 50; 100; 200; 400; 800; 1,600; 3.200; 6,400 and 12,800 kg/ha of K(2)0. In the conditions observed during the present work, results allowed the following conclusions: A response by soybean grain production for doses of potassium chloride, applied in both ways, banded or broadcasted, was not observed. Leaf analysis did not show treatment influence over the leaf contents for N, P, K, Ca, Mg, and CI, Potassium chloride salinity effects in both methods of distribution for all the tested closes were not observed.