Experimental analysis of the thermal entrainment factor of air curtains in vertical open display cabinets for different ambient air conditions

This study presents a three-dimensional Computational Fluid Dynamics (CFD) simulation of the air flow pattern and the temperature distribution in a refrigerated display cabinet. The thermal entrainment is evaluated by the variations of the mass flow rate and thermal power along and across the air curtain considering the numerical predictions of abovementioned properties. The evaluation on the ambient air velocity for the three-dimensional (3D) effects in the pattern of this type of turbulent air flow is obtained. Additionally, it is verified that the longitudinal air flow oscillations and the length extremity effects have a considerable influence in the overall thermal performance of the equipment. The non uniform distribution of the air temperature and velocity throughout the re-circulated air curtain determine the temperature differences in the linear display space and inside the food products, affecting the refrigeration power of display cabinets. The numerical predictions have been validated by comparison with experimental tests performed in accordance with the climatic class n.° 3 of EN 441 Standard (Tamb = 25 °C, φamb = 60%; νamb = 0,2 m s−1). These tests were conducted using the point measuring technique for the air temperature, air relative humidity and air velocity throughout the air curtain, the display area of conservation of food products and nearby the inlets/outlets of the air mass flow.

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EXPERIMENTAL ANALYSIS IN INDOOR THERMAL ENVIRONMENT IN TASK AND AMBIENT AIR-CONDITIONING SYSTEM USING STAND-ALONE PERSONAL HEAT PUMP UNIT

Journal of Architecture and Planning (Transactions of AIJ) ◽

10.3130/aija.59.29_2 ◽

1994 ◽

Vol 59 (463) ◽

pp. 29-37 ◽

Cited By ~ 2

Author(s):

Kexin LI ◽

Hisahiro ITO ◽

Nobuo NAKAHARA

Keyword(s):

Heat Pump ◽

Experimental Analysis ◽

Air Conditioning ◽

Thermal Environment ◽

Ambient Air ◽

Pump Unit ◽

Air Conditioning System ◽

Indoor Thermal Environment ◽

Heat Pump Unit

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Development of a Rapid Survey Method of Sampling and Analysis for Asbestos in Ambient Air

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096400 ◽

1972 ◽

Vol 30 ◽

pp. 630-631 ◽

Cited By ~ 2

Author(s):

R. E. Heffelfinger ◽

C. W. Melton ◽

D. L. Kiefer ◽

W. M. Henry ◽

R. J. Thompson

Keyword(s):

Neutron Activation ◽

Ambient Air ◽

Survey Method ◽

Potential Hazard ◽

Transmission Microscopy ◽

Comparative Analyses ◽

Asbestos Fibers ◽

Controlled Conditions ◽

Unequivocal Identification ◽

Identification And Quantification

A methodology has been developed and demonstrated which is capable of determining total amounts of asbestos fibers and fibrils in air ranging from as low as fractional nanograms per cubic meter (ng/m3) of air to several micrograms/m3. The method involves the collection of samples on an absolute filter and provides an unequivocal identification and quantification of the total asbestos contents including fibrils in the collected samples.The developed method depends on the trituration under controlled conditions to reduce the fibers to fibrils, separation of the asbestos fibrils from other collected air particulates (beneficiation), and the use of transmission microscopy for identification and quantification. Its validity has been tested by comparative analyses by neutron activation techniques. It can supply the data needed to set emissions criteria and to serve as a basis for assessing the potential hazard for asbestos pollution to the populace.

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Application of Electron Optics to Characterization of Particulate Pollutants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009508x ◽

1972 ◽

Vol 30 ◽

pp. 364-365

Author(s):

J. B. Moran ◽

J. L. Miller

Keyword(s):

Air Quality ◽

Quality Standards ◽

Ambient Air ◽

Hazardous Substances ◽

Fuel Additives ◽

Ambient Air Quality ◽

Air Quality Standards ◽

Emission Standards ◽

Stationary Sources ◽

Ambient Air Quality Standards

The Clean Air Act Amendments of 1970 provide the basis for a dramatic change in Federal air quality programs. The Act establishes new standards for motor vehicles and requires EPA to establish national ambient air quality standards, standards of performance for new stationary sources of pollution, and standards for stationary sources emitting hazardous substances. Further, it establishes procedures which allow states to set emission standards for existing sources in order to achieve national ambient air quality standards. The Act also permits the Administrator of EPA to register fuels and fuel additives and to regulate the use of motor vehicle fuels or fuel additives which pose a hazard to public health or welfare.National air quality standards for particulate matter have been established. Asbestos, mercury, and beryllium have been designated as hazardous air pollutants for which Federal emission standards have been proposed.

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Electron Microscopic Characterization and Quantitation of Air Borne Particulate Matter with Special Emphasis on Asbestos

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095042 ◽

1972 ◽

Vol 30 ◽

pp. 356-357

Author(s):

Peter K. Mueller ◽

Glenn R. Smith ◽

Leslie M Carpenter ◽

Ronald L. Stanley

Keyword(s):

Electron Microscopy ◽

Light And Electron Microscopy ◽

Ambient Air ◽

Quality Standard ◽

Primary Objective ◽

Cellulose Ester ◽

Main Concept ◽

Electron Microscopic ◽

Air Samples ◽

Diffraction Patterns

At the present time the primary objective of the electron microscopy group of the Air and Industrial Hygiene Laboratory is the development of a method suitable for use in establishing an air quality standard for asbestos in ambient air and for use in its surveillance. The main concept and thrust of our approach for the development of this method is to obtain a true picture of fiber occurrence as a function of particle size and asbestos type utilizing light and electron microscopy.We have now available an electron micrographic atlas of all asbestos types including selected area diffraction patterns and examples of fibers isolated from air samples. Several alternative approaches for measuring asbestos in ambient air have been developed and/or evaluated. Our experiences in this regard will be described. The most promising method involves: 1) taking air samples on cellulose ester membrane filters with a nominal pore size of 0.8 micron; 2) ashing in a low temperature oxygen plasma for several hours;

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