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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.
1

Maximizing capacity of underground mine water chilling machines rejecting heat into a limited supply of water pumped to surface

Wright, Clifford Dale 26 July 2016 (has links)
A project report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2016 / Underground chilling installations have an important role in deep mining operations because the total cost of cooling a mine is minimized when underground machines deliver as high a proportion of the required cooling as practicable. Thus the refrigerating load of an underground installation should be maximized to the extent permitted both by the environment in which the installation operates, and by the physical characteristics of the machines in the installation. This study analyses how, and to what extent, the refrigerating load of older, already installed water chilling machines rejecting heat into a limited supply of return water may be maximized through configuration of their water circuits and capacity control of their compressors. Multiple-machine installations are simulated in a range of scenarios, using the thermodynamically efficient series-counterflow arrangement, to predict both the potential maximum refrigerating load and the expected refrigerating load of such installations. The simulation results indicate significant potential for installations to chill water more efficiently and thus deliver larger, maximized, refrigerating loads. For scenarios where a larger-than-design flowrate of return water is available, so permitting machines to be operated with little or no capacity control, the simulated chilling efficiency and thus the expected refrigerating loads tend toward, and in some cases almost match, the potential maximum values. For simulations in which compressor capacity control is used to prevent the return water temperature from exceeding its maximum permitted value, expected refrigerating loads fall short of their potential values, by varying amounts, due to the low machine cycle efficiency caused largely by reduced compressor isentropic efficiency at part load. For a limited supply of return water for heat rejection, the simulations indicate that load maximization efforts should focus on the machines in an installation being connected in a series-counterflow arrangement and operated, as far as practicable, at or near full capacity to create the best prospect for approaching potential maximum refrigerating load.
2

Natural ventilation in buildings: the development of a component

Hahn, Philip Mitchell January 1983 (has links)
M.Arch.
3

Functional model and second law analysis method for energy efficient process design: applications in HVAC systems design

Harutunian, Vigain 28 August 2008 (has links)
Not available / text
4

Ozone interactions with HVAC filters

Zhao, Ping 28 August 2008 (has links)
Not available / text
5

Evaluation of possibilities for processes integration in ventilation equipment / Procesų integravimo vėdinimo įrenginiuose galimybių vertinimas

Misevičiūtė, Violeta 06 February 2012 (has links)
The dissertation investigates the issues of efficient energy use in building engineering systems possibilities by applying processes integration. Indoor climate formation systems are indicated as signally energy use building engineering systems. Traditional methods for evaluation of heat transfer in heat exchangers tender limited solutions for efficiency use of energy in them. The main object of dissertation is to evaluate processes integration method application possibilities for determination and improving of public buildings engineering systems. The dissertation also focuses on combine the possibilities of processes integration in building engineering systems with minimizing exergy streams in the systems. The paper approaches a few major tasks: determination of problematic building engineering systems, equipment and processes by viewpoint of energy efficiency, analysis of ventilation design solutions, creation of algorithm for exergy input minimizing in building engineering systems processes by combination of thermodynamical and Pinch analysis methods. The dissertation consists of four parts including Introduction, 4 chapters, Conclusions and References. The introduction reveals the investigated problem, importance of the thesis and the object of research and describes the purpose and tasks of the paper, research methodology, scientific novelty, the practical significance of results examined in the paper and defended statements. The introduction ends in presenting the... [to full text] / Disertacijoje nagrinėjamos procesų integracijos metodo taikymo galimybės sprendžiant efektyvaus energijos vartojimo pastatų inžinerinėse sistemose problemas. Tarp pastato inžinerinių sistemų darbe išskiriamos ženkliau energiją naudojančios, mikroklimatą pastatuose formuojančios sistemos. Klasikiniai tyrimo metodai, skirti šilumos mainams šilumokaičiuose, kurie atlieka šilumos perdavimo funkciją, nagrinėti pateikia gana ribotus sprendinius, kaip efektyviai naudoti energiją juose. Pagrindinis disertacijos tikslas – įvertinti procesų integravimo metodo taikymo galimybes viešųjų pastatų inžinerinių sistemų termodinaminiam efektyvumui nustatyti ir gerinti. Disertacijoje taip pat siekiama derinti procesų integracijos galimybes inžinerinėse sistemose siekiant minimizuoti eksergijos srautus jose. Darbe sprendžiami keli pagrindiniai uždaviniai: probleminių, energinio efektyvumo požiūriu, pastato inžinerinių sistemų, įrenginių ir procesų jose nustatymas, vėdinimo sistemų projektinių sprendimų ypatybių nustatymas, algoritmo, skirto procesų eksergijos sąnaudoms mažinti pastato inžinerinėse sistemose sudarymas derinant termodinaminės ir Pinch analizės metodus. Disertaciją sudaro įvadas, keturi skyriai, rezultatų apibendrinimas, naudotos literatūros ir autorės publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas... [toliau žr. visą tekstą]
6

Procesų integravimo vėdinimo įrenginiuose galimybių vertinimas / Evaluation of possibilities for processes integration in ventilation equipment

Misevičiūtė, Violeta 06 February 2012 (has links)
Disertacijoje nagrinėjamos procesų integracijos metodo taikymo galimybės sprendžiant efektyvaus energijos vartojimo pastatų inžinerinėse sistemose problemas. Tarp pastato inžinerinių sistemų darbe išskiriamos ženkliau energiją naudojančios, mikroklimatą pastatuose formuojančios sistemos. Klasikiniai tyrimo metodai, skirti šilumos mainams šilumokaičiuose, kurie atlieka šilumos perdavimo funkciją, nagrinėti pateikia gana ribotus sprendinius, kaip efektyviai naudoti energiją juose. Pagrindinis disertacijos tikslas – įvertinti procesų integravimo metodo taikymo galimybes viešųjų pastatų inžinerinių sistemų termodinaminiam efektyvumui nustatyti ir gerinti. Disertacijoje taip pat siekiama derinti procesų integracijos galimybes inžinerinėse sistemose siekiant minimizuoti eksergijos srautus jose. Darbe sprendžiami keli pagrindiniai uždaviniai: probleminių, energinio efektyvumo požiūriu, pastato inžinerinių sistemų, įrenginių ir procesų jose nustatymas, vėdinimo sistemų projektinių sprendimų ypatybių nustatymas, algoritmo, skirto procesų eksergijos sąnaudoms mažinti pastato inžinerinėse sistemose sudarymas derinant termodinaminės ir Pinch analizės metodus. Disertaciją sudaro įvadas, keturi skyriai, rezultatų apibendrinimas, naudotos literatūros ir autorės publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas... [toliau žr. visą tekstą] / The dissertation investigates the issues of efficient energy use in building engineering systems possibilities by applying processes integration. Indoor climate formation systems are indicated as signally energy use building engineering systems. Traditional methods for evaluation of heat transfer in heat exchangers tender limited solutions for efficiency use of energy in them. The main object of dissertation is to evaluate processes integration method application possibilities for determination and improving of public buildings engineering systems. The dissertation also focuses on combine the possibilities of processes integration in building engineering systems with minimizing exergy streams in the systems. The paper approaches a few major tasks: determination of problematic building engineering systems, equipment and processes by viewpoint of energy efficiency, analysis of ventilation design solutions, creation of algorithm for exergy input minimizing in building engineering systems processes by combination of thermodynamical and Pinch analysis methods. The dissertation consists of four parts including Introduction, 4 chapters, Conclusions and References. The introduction reveals the investigated problem, importance of the thesis and the object of research and describes the purpose and tasks of the paper, research methodology, scientific novelty, the practical significance of results examined in the paper and defended statements. The introduction ends in presenting the... [to full text]

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