Solar Energy Collection With Evacuated Tubes

1965 ◽  
Vol 87 (3) ◽  
pp. 270-276 ◽  
Author(s):  
E. Speyer
Keyword(s):  
Solar Energy ◽  
Mass Production ◽  
Air Conditioning ◽  
Tube Wall ◽  
Glass Tube ◽  
Different Temperatures ◽  
Evacuated Tubes ◽  
Liquid Flows ◽  
Evacuated Tube ◽  
Economic Considerations

Engineering and economic considerations are given for nontracking solar energy collectors where the absorbing surface is insulated by an evacuated space. Each collector is a long glass tube, about two in. in dia, silvered in the lower portion. The selectively blackened conduit through which liquid flows is suspended within the evacuated tube, passing through the tube wall at only one end. Prototype tubular collectors were built, and tested when evacuated and when air-filled. The measured efficiencies at different temperatures are given, and the data fitted by empirical equations. Costs per tube and per Btu are given together with an indication of applicability to solar air conditioning. Mass production of these collectors will depend on the indicated demand.

scholarly journals Application of Solar Energy to Continuous Belt Dehydration

1979 ◽  
Author(s):  
B. J. Graham
Keyword(s):  
Solar System ◽  
Natural Gas ◽  
Solar Energy ◽  
Department Of Energy ◽  
Dehydration Process ◽  
Evacuated Tubes ◽  
Evacuated Tube Collectors ◽  
Evacuated Tube

A solar system utilizing a 553-m2 (5950-ft2) array of evacuated tube collectors has been designed to augment the heat supplied by natural gas to a Proctor & Schwartz continuous belt dryer used for processing onions and garlic at the Gilroy Foods plant in Gilroy, California. It has been calculated that the array, which contains 3216 evacuated tubes, will contribute 2.47 × 1012 J/yr (2340 MBtu/yr) to the dehydration process. The system is currently being installed and will be operational for drying in May 1979. This project was sponsored by the U. S. Department of Energy under Contract No. E-(40-1)-5119.

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.

Evacuated Tube Heat Pipe Solar Collectors Applied to Recirculation Loop in a Federal Building: SSA Philadelphia

Solar Energy ◽  
2004 ◽  
Author(s):  
Andy Walker ◽  
Fariborz Mahjouri ◽  
Robert Stiteler
Keyword(s):  
Solar Energy ◽  
Heat Pipe ◽  
Heat Loss ◽  
Heating System ◽  
Hot Water ◽  
Solar Array ◽  
Solar Collectors ◽  
Water Heating ◽  
Evacuated Tube ◽  
Recirculation Loop

This paper describes design, simulation, construction and measured initial performance of a solar water heating system (360 Evacuated Heat-Pipe Collector tubes, 54 m2 gross area, 36 m2 net absorber area) installed at the top of the hot water recirculation loop in the Social Security Mid-Atlantic Center in Philadelphia. Water returning to the hot water storage tank is heated by the solar array when solar energy is available. This new approach, as opposed to the more conventional approach of preheating incoming water, is made possible by the thermal diode effect of heat pipes and low heat loss from evacuated tube solar collectors. The simplicity of this approach and its low installation costs makes the deployment of solar energy in existing commercial buildings more attractive, especially where the roof is far removed from the water heating system, which is often in the basement. Initial observed performance of the system is reported. Hourly simulation estimates annual energy delivery of 111 GJ/year of solar heat and that the annual efficiency (based on the 54 m2 gross area) of the solar collectors is 41%, and that of the entire system including parasitic pump power, heat loss due to freeze protection, and heat loss from connecting piping is 34%. Annual average collector efficiency based on a net aperture area of 36 m2 is 61.5% according to the hourly simulation.

scholarly journals MEASUREMENT OF THE EFFICIENCY OF EVACUATED TUBE SOLAR COLLECTORS UNDER VARIOUS OPERATING CONDITIONS

2012 ◽  
Vol 7 (3) ◽  
pp. 114-130 ◽  
Author(s):  
S. E. Zubriski ◽  
K. J. Dick
Keyword(s):  
Environmental Conditions ◽  
Operating Conditions ◽  
Hot Water ◽  
Heat Transfer Fluid ◽  
Operating Efficiency ◽  
Space Heating ◽  
Solar Collectors ◽  
Auxiliary Equipment ◽  
Evacuated Tubes ◽  
Evacuated Tube

The operating efficiency of evacuated tubes themselves under varying environmental conditions and installation scenarios, independent of water and space heating auxiliary equipment, are not readily available values. Further, Manitoba specific data has not been established. The purpose of this research program was to measure the efficiency of evacuated tube solar collectors under various operating conditions including: the angle of inclination towards the incident solar radiation, heat transfer fluid flow rate, glazing installation, and number of evacuated tubes. The operating conditions and configurations were chosen to represent realistic or probable installation scenarios and environmental conditions. Furthermore, the research aimed to identify the suitability of evacuated tube solar collectors to each of the scenarios. These design values are of use for appropriate sizing of water or space heating systems, system configuration and optimization, and calculation of return on investment. The scope of the research project was limited to the efficiency of various configurations of a 32-tube panel, not the entire solar domestic hot water or space heating system. Thus, factors such as heat loss in the tubing, solar storage tank, and heat exchanger efficiency were not investigated. The findings indicated that efficiency varied by approximately 5% between the different collector configurations, as observed from the overlay graph of results. When the efficiency of a collector is considered within a system it is proposed that effectiveness may be a better measure of overall performance.

Investigation of solar energy utilization in a novel desiccant based air conditioning system

2012 ◽  
Vol 55 ◽  
pp. 757-764 ◽  
Author(s):  
Ertaç Hürdoğan ◽  
Orhan Büyükalaca ◽  
Tuncay Yılmaz ◽  
Arif Hepbasli ◽  
İrfan Uçkan
Keyword(s):  
Solar Energy ◽  
Air Conditioning ◽  
Energy Utilization ◽  
Air Conditioning System ◽  
Solar Energy Utilization

Heat Stress and School Closings

PEDIATRICS ◽  
1984 ◽  
Vol 74 (2) ◽  
pp. 313-314
Author(s):  
Keyword(s):  
Heat Stress ◽  
Public Schools ◽  
Air Conditioning ◽  
Radiant Heat ◽  
Excessive Heat ◽  
Southern States ◽  
Teachers And Students ◽  
Different Temperatures ◽  
Hot Weather ◽  
American Society

During the last decade, the practice of opening public school in eary August has led to environmental stresses on students and teachers due to extremes of heat and humidity. In the South and Southwest, it is not unusual to have 15 to 20 days of 90°F(32.2°C) and relative humidity of 60% and higher during August. This puts a strain on teachers' and students' adaptability. In surveying eight southern states, J. W. Trieschmann (unpublished data, 1983) found that the availability of air conditioning in public schools ranged from 15% in some states to 30% in others. The smaller, poorer, usually rural school districts had the least access to cooling equipment. Thus, a large school population is at the mercy of the elements. This is especially significant because the majority of this population has been acclimatized to air-conditioned homes and stores, and extremes of heat discomfort are not well tolerated. Heat stress is defined as the overall effect of excessive heat on the human body. The important factors contributing to heat stress are air temperature, humidity, air movement, radiant heat, atmospheric pressure, physiologic factors (handicap or chronic disease), physical activity,1 and time exposure. Under normal conditions, temperature and humidity are the most important elements influencing comfort. The American Society of Heating, Refrigeration, Air Conditioning Engineers (ASHRAE) has published an index for determining heat stress based on human physiology, clothing, and standard room conditions.2 This index, called the "ET" or effective temperature (in Fahrenheit), is a measure of what hot weather feels like to the average person at different temperatures and humidities.

scholarly journals Design and Thermo-Economic Comparisons of an Absorption Air Conditioning System Based on Parabolic Trough and Evacuated Tube Solar Collectors

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3198 ◽  
Author(s):  
Adil Al-Falahi ◽  
Falah Alobaid ◽  
Bernd Epple
Keyword(s):  
Air Conditioning ◽  
Thermal Power ◽  
Lithium Bromide ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Parabolic Trough ◽  
Solar Absorption ◽  
Pumping System ◽  
Economic Analyses ◽  
Evacuated Tube

Solar absorption cycles for air conditioning systems have recently attracted much attention. They have some important advantages that aid in reducing greenhouse gas emissions. In this work, design and thermo-economic analyses are presented in order to compare between two different collector types (parabolic trough and evacuated tube) by water–lithium bromide absorption systems, and to select the best operating conditions. Generally, the system consists of three major parts. The first part is the solar field for thermal power conversion. The second part is the intermediate cycle, which contains a flashing tank and pumping system. The third part is the water lithium bromide absorption chiller. A case study for a sports arena with 700–800 kW total cooling load is also presented. Results reveal that a parabolic trough collector combined with H2O–LiBr (PTC/H2O–LiBr) gives lower design aspects and minimum rates of hourly costs (USD 5.2/h), while ETC/H2O–LiBr configuration give USD 5.6/h. The H2O–LiBr thermo-economic product cost is USD 0.14/GJ. The cycle coefficient of performance COP was in the range of 0.5 to 0.9.

Review of Materials and Environment Management for Solar Thermal Collectors

2014 ◽  
Vol 521 ◽  
pp. 539-542
Author(s):  
Da Yu Zheng ◽  
Juan Zheng ◽  
Xiang Yi Guan ◽  
Jia Zheng ◽  
Yi Ming Zhang
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Pipe ◽  
Research Work ◽  
Solar Thermal ◽  
Senior Managers ◽  
Solar Thermal Collectors ◽  
Evacuated Tubes ◽  
Evacuated Tube Collectors ◽  
Evacuated Tube

To cover the main contributions and developments in solar thermal collectors through focusing on materials, heat transfer characteristics and manufacturing challenges. A range of published papers and internet research including research work on various solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube) were used. Evaluation of solar collectors performance is critiqued to aid solar technologies make the transition into a specific dominant solar collector. The sources are sorted into sections: finding an academic job, general advice, teaching, research and publishing, tenure and organizations. Provides information about types of solar thermal collectors, indicating what can be added by using evacuated tube collectors instead of flat plate collectors and what can be added by using heat pipe collectors instead of evacuated tubes. Focusing only on three types of solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube). Useful source of information for consultancy and impartial advice for graduate students planning to do research in solar thermal technologies. This paper fulfils identified information about materials and heat transfer properties of materials and manufacturing challenges of these three solar thermal collectors. Describes some changes made to improve the environment which have had unforeseen and adverse effects on safety and the reasons why we need more case histories. Also discusses the reasons why there are no permanent solutions to safety problems and the reasons why senior managers should become more involved in safety problems.

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