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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

An investigation into the effects of lubricating oil on heat pump evaporator performance and possible cycle improvements utilising a regenerative expansion process

Masson, Alan John January 1989 (has links)
No description available.

Theoretical study of an absorption refrigeration system powered by CPC solar collectors for applications at near equatorial latitudes

Babawale, Z. A. January 1988 (has links)
No description available.

Investigation and performance optimisation of multi compressor refrigeration system

Chan, Kuan Yoong January 2002 (has links)
No description available.

Demagnetizing effects in active magnetic regenerators

Peksoy, Ozan. 10 April 2008 (has links)
No description available.

Investigation of the entrainment and infiltration rates through air curtains of open low-front refrigerated display cabinets

Al-Sahhaf, Ahmad Ali January 2013 (has links)
The high energy demand associated with open multi-deck refrigerated display cabinets is a direct consequence of their open design. The interaction between the cold refrigerated air inside the cabinet and the relatively warm air of the supermarket takes place across the air curtain, which serves as a non-physical barrier between the customers and the products. It has been estimated that 70% to 80% of the cabinet’s cooling load is due to ambient air infiltration into the cabinet refrigeration apparatus, which was previously entrained through the descending air curtain. A new generation of display cabinets has immerged in recent years, where the display-to-floor area has increased for the sake of maximizing sales. This modification leaves the air curtain with a larger display opening to seal against. Therefore, the design of such cabinets has now become more challenging, especially when attempting to ensure product integrity and temperature homogeneity while attempting to minimize their energy consumption. In this work, advanced numerical and experimental techniques have been integrated to quantify and also minimize the entrainment rate through the air curtain and the infiltration rate into open low-front refrigerated display cabinets. Experimentally, the Particle Image Velocimetry (PIV) technique has been used to map the velocity profile along the air curtain while the Infrared (IR) Thermography technique has been used to map the temperature profile across the cabinet. The Computational Fluid Dynamics (CFD) technique has been used in both case and parametric studies after confirming its validation with experiment. CFD was found to be a valuable tool for the simulation of open low-front refrigerated display cabinets, and the credibility of the results was assured when the boundary conditions were fine-tuned by experimental data. This thesis has demonstrated a systematic procedure where the entrainment rate through the air curtain can be quantified. The effect of various Discharge Air Grille (DAG) parameters was studied, and it was found that the entrainment rate is highly sensitive to the velocity profile and magnitude at the DAG. A velocity profile with a ramp shape having the maximum velocity near the cabinet yielded the minimum entrainment rate, hence the cabinet cooling load was reduced. In addition, two techniques were introduced for the determination of the infiltration rate of the cabinet. The first utilises the tracer-gas method to determine the specific amounts of ambient dry air and water vapour entering the evaporator coil, and the second uses psychrometrics to quantify the infiltration load as well as the other cooling load components by identifying the various heat transfer processes encountered during the operation of the cabinet. The ambient air infiltrated into the cabinet, although corresponds to 31% of the total mass flow rate, was found to be responsible for at least 85% of the total cooling load of the cabinet. This indicates that low-front cabinet suffer more from infiltration. The contribution of this work is by providing a better understanding towards the entrainment and infiltration processes related to open refrigerated display cabinets. The new techniques introduced in this work can help designers to better assess the impact of different design parameters and quantify the amounts of the entrainment and infiltration rates associated with open low-front refrigerated display cabinets.

The design and development of a magnetic refrigerator

Mand, G. S. January 1987 (has links)
A new tvpe ot macnetic retricerator usine a rotatine belt eeometrv has been desiened and developed. The retricerator u.e. the maenetocaloric ettect. that is. the heat inc or cooline ot a maenetic material on application or removal ot a maen.tic tield. to execute a Carnot cvcle. An antiterromaanetic material. Gadolinium Gallium Garnet, Gd3Gas012 (GGG) , i. used ae the retricerant. This is in the torm ot a belt which run. throuch the bore ot a .uperconduct1na solenoid macnet to execute the cyole. The retricerator has been developed in three staces, Fir.tlv the belt ceometry was de.icned. oonstructed and te.ted. This lead to the development ot the model one retricerator. and ba.ed on the.e results the model two retriaerator was con.tructed. Re.ult •• trom the model two retricerator. show an anomalous temperature increa.e in the .ource recion resul tine trom a re - lIlaenetieation ot the belt. Purthermore. entrained tluid ettects limit the operatinc temperature span. However. the belt concept has been .ucce.etullv realised with it beina operated at trequencie. ot up to 30 rpm in macnetic tields not exceedine "T.

Comparative study of a steam jet refrigeration system and compression refrigeration systems for a central cooling plant

Vachhani, Vasantrai Ambavi, 1936- January 1963 (has links)
No description available.

The economy and commercial possibilities of the small refrigerating plant

Beatty, Philip J. January 1926 (has links)
No description available.

The design and care of refrigerating apparatus

Holland, Archibald Dinsmore 08 1900 (has links)
No description available.

Performance characteristics of various refrigeration expansion valves

Lauderdale, Woodrow Wilson 08 1900 (has links)
No description available.

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