Optimization of Heat Losses of Concentric Coaxial Glass Tube Solar Air Collector

2020 ◽  
Vol 01 (02) ◽  
pp. 25-39
Author(s):  
Vishal Dabra
Keyword(s):  
Glass Tube ◽  
Heat Losses ◽  
Solar Air Collector

scholarly journals Tilt optimization of a double-glazed air solar collector prototype

2018 ◽  
Vol 240 ◽  
pp. 04006 ◽  
Author(s):  
Hocine Mzad ◽  
Abdessalam Otmani ◽  
Abdallah Haouam ◽  
Stanisław Łopata ◽  
Pawel Ocłoń
Keyword(s):  
Wind Speed ◽  
Performance Optimization ◽  
Solar Collector ◽  
Heat Losses ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Air Flow Rate ◽  
Solar Air Collector ◽  
Temperature Heat ◽  
Fluid Properties

To understand usage of solar air collector there are factors that have influence on the performance. The goal of this paper is to investigate a solar air collector prototype in order to perform a performance optimization using the possible min imum of equations. The thermal efficiency, fluid outlet temperature, heat increase and heat losses of the collector are calculated depending on the collector geometry, fluid properties, fluid inlet temperature, air flow rate, solar insulation and ambient temperature. The calculations were performed using actual data of temperature, wind speed and the global-horizontal radiation Hh over the year 2011 at the international airport of Annaba city. Comparison of results reveals that optimal efficacy is obtained for south facing panels with an inclination angle ß comprised in the interval [15°, 35°]. These conditions provide a useful energy exceeding 4300 W and an efficiency of about 51 %.

scholarly journals Experimental Investigation of Heat Losses from a Heat Pipe Based Parabolic Trough Collector used for Direct Steam Generation

2021 ◽  
pp. 31-39
Author(s):  
Abiem Louis Tersoo ◽  
Akoshile Clement Olufemi
Keyword(s):  
Experimental Investigation ◽  
Thermal Efficiency ◽  
Glass Tube ◽  
Heat Losses ◽  
Solar Thermal ◽  
Thermal System ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Direct Steam ◽  
Solar Thermal System

The performance of a thermosiphon based parabolic trough collector (PTC) used for direct steam generation depends largely on the heat losses of the solar thermal system. This paper presents an experimental investigation of the heat losses in a thermosiphon based solar thermal system that used a linear receiver with a PTC for the generation of low temperature steam. A locally constructed PTC was used to concentrate sun rays to a linear copper pipe enclosed in an evacuated glass tube and held at the focal line of the PTC to heat water and generate steam. Circulation of the water in the closed-loop solar thermal system was through natural convection. A solar meter was used to measure the incident radiation flux at the experimental site and PT100 temperature sensors were installed at different points of the system to measure the temperature distribution within the system. The thermal efficiency and overall heat losses of the system were investigated by fitting the experimental data to standard equations. The results showed that the instantaneous thermal efficiency of the system was 46.48%, 43.1% and 45.32% respectively for three days examined. The overall heat losses in the system were 1211.95, 974.32 and 911.26 kwh per day respectively for the three days investigated. Heat losses from the tank accounted for over 83% of the losses for all the days examined. The evacuated glass tube reduced heat losses from the receiver to very low values of 2.31, 1.63 and 1.43 KWh per day respectively for the three days tested. The use of a better insulating material on the tank was recommended to reduce convective and conductive heat losses, thereby enhancing the performance of the system.

Performance of a new type of solar air collector with transparent-vacuum glass tube based on micro-heat pipe arrays

Energy ◽  
2019 ◽  
Vol 177 ◽  
pp. 16-28 ◽  
Author(s):  
Teng-yue Wang ◽  
Yao-hua Zhao ◽  
Yan-hua Diao ◽  
Ru-yang Ren ◽  
Ze-yu Wang
Keyword(s):  
Heat Pipe ◽  
Glass Tube ◽  
Micro Heat Pipe ◽  
Solar Air Collector ◽  
New Type

Thermal performance of solar air collector with transparent honeycomb made of glass tube

2009 ◽  
Vol 52 (8) ◽  
pp. 2323-2329 ◽  
Author(s):  
ZhiQiang Zhang ◽  
Ran Zuo ◽  
Ping Li ◽  
WenJia Su
Keyword(s):  
Thermal Performance ◽  
Glass Tube ◽  
Solar Air Collector

Exogeneous factors are not necessary in attachment, spreading and polarization of hela cells

1978 ◽  
Vol 36 (2) ◽  
pp. 310-311
Author(s):  
W. Liebrich
Keyword(s):  
Hela Cells ◽  
Calf Serum ◽  
Glass Tube ◽  
Serum Free Medium ◽  
Nacl Solution ◽  
Free Medium ◽  
Minimum Essential Medium ◽  
Serum Free ◽  
All Solutions ◽  
Glass Support

HeLa cells were grown for 2-3 days in EAGLE'S minimum essential medium with 10% calf serum (S-MEM; Seromed, München) and then incubated for 24 hours in serum free medium (MEM). After detaching the cells with a solution of 0. 14 % EDTA and 0. 07 % trypsin (Difco, 1 : 250) they were suspended in various solutions (S-MEM = control, MEM, buffered salt solutions with or without Me++ions, 0. 9 % NaCl solution) and allowed to settle on glass tube slips (Leighton-tubes). After 5, 10, 15, 20, 25, 30, 1 45, 60 minutes 2, 3, 4, 5 hours cells were prepared for scanning electron microscopy as described by Paweletz and Schroeter. The preparations were examined in a Jeol SEM (JSM-U3) at 25 KV without tilting.The suspended spherical HeLa cells are able to adhere to the glass support in all solutions. The rate of attachment, however, is faster in solutions without serum than in the control. The latter is in agreement with the findings of other authors.

Electron sources: Past, present, and future

1993 ◽  
Vol 51 ◽  
pp. 764-765
Author(s):  
David C Joy
Keyword(s):  
Glass Tube ◽  
Source Size ◽  
Electron Gun ◽  
Operating Parameters ◽  
Operational Parameters ◽  
Electron Sources ◽  
Difficult Decision ◽  
Probe Size ◽  
Wide Range ◽  
Overall Performance

The electron source is the most important component of the Scanning electron microscope (SEM) since it is this which will determine the overall performance of the machine. The gun performance can be described in terms of quantities such as its brightness, its source size, its energy spread, and its stability and, depending on the chosen application, any of these factors may be the most significant one. The task of the electron gun in an SEM is, in fact, particularly difficult because of the very wide range of operational parameters that may be required e.g a variation in probe size of from a few angstroms to a few microns, and a probe current which may go from less than a pico-amp to more than a microamp. This wide range of operating parameters makes the choice of the optimum source for scanning microscopy a difficult decision.Historically, the first step up from the sealed glass tube ‘cathode ray generator’ was the simple, diode, tungsten thermionic emitter.

Observation of the Sulphur Atoms in Cu2S Using HREM

1990 ◽  
Vol 48 (1) ◽  
pp. 38-39
Author(s):  
Y.D. Yu ◽  
R. Guan ◽  
K.H. Kuo ◽  
H. Hashimoto
Keyword(s):  
Electron Diffraction ◽  
Tube Wall ◽  
Present Report ◽  
Dynamic Effect ◽  
Glass Tube ◽  
Fluorite Structure ◽  
Point Of View ◽  
Electron Diffraction Analysis ◽  
Sulphur Atom ◽  
Copper Thin Film

We have indicated that the lighter atoms such as oxygen in Cu2O can be observed at the specimen with optimal thicknesses based on the dynamic effect of electron diffraction(1). This rule in principle should hold good for the imaging of other lighter atoms such as sulphur atom in Cu2S. However, this point of view needs further experimentally confirm because up to now only oxygen atoms have been observed in Cu2O and a series of new suboxides of copper and nickel (2). In addition, the sulphur atom is much heavier than oxygen one though is still lighter than copper atom. In the present report we provide such a confirmation.The crystallites of Cu2S shown in Fig.l were obtained by sulfurizing at 300°C of the copper thin film which was sealed in a glass tube with mg sulphur left on the tube wall in a vacuum of about 10-2 Pa. The energy dispersive spectrocscopy analysis indicated that they are the sulfides and the electron diffraction analysis indicated they have anti-fluorite structure.

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