The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Guilherme B. Ribeiro - One of the best experts on this subject based on the ideXlab platform.
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Une nouvelle boucle frigorifique à compression de vapeur pour de hautes températures ambiantes
International Journal of Refrigeration, 2016Co-Authors: Guilherme B. RibeiroAbstract:Refrigeration Equipment as the compressor has had its size reduced and cooling capacity increased in the last years, which leads to a continuous rise of the level of heat flux dissipated through the compressor shell and may cause reliability issues related to the compressor's moving parts. Furthermore, extreme conditions as high ambient temperatures augment the importance of keeping the compressor shell temperature under safe limits. To overcome such difficulties, a novel vapor-compression refrigerating loop was created especially for the compressor thermal management. A cooling unit was assembled using the proposed loop and later compared experimentally with two thermoelectric coolers under ambient temperatures of 25, 35 and 55 °C. The results have shown that the novel refrigerating loop enables the vapor-compression unit to work at a high ambient temperature (55 °C) and nearly a two times higher coefficient of performance (COP) was achieved, when compared to thermoelectric solutions.
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A novel vapor-compression Refrigeration loop for high ambient temperatures
International Journal of Refrigeration, 2016Co-Authors: Guilherme B. RibeiroAbstract:Abstract Refrigeration Equipment as the compressor has had its size reduced and cooling capacity increased in the last years, which leads to a continuous rise of the level of heat flux dissipated through the compressor shell and may cause reliability issues related to the compressor's moving parts. Furthermore, extreme conditions as high ambient temperatures augment the importance of keeping the compressor shell temperature under safe limits. To overcome such difficulties, a novel vapor-compression refrigerating loop was created especially for the compressor thermal management. A cooling unit was assembled using the proposed loop and later compared experimentally with two thermoelectric coolers under ambient temperatures of 25, 35 and 55 °C. The results have shown that the novel refrigerating loop enables the vapor-compression unit to work at a high ambient temperature (55 °C) and nearly a two times higher coefficient of performance (COP) was achieved, when compared to thermoelectric solutions.
Renaud Metz - One of the best experts on this subject based on the ideXlab platform.
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Environmental declaration in compliance with ISO 14025 thanks to a collaborative program of electrical and electronic industry: The PEP ecopassport program
22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013), 2013Co-Authors: Mehrdad Hassanzadeh, Claude Jollain, Serge Theoleyre, Renaud MetzAbstract:The need for environmental product impacts information in the electrical, electronic and HVAC-R (heating, ventilation, air-conditioning, Refrigeration) Equipment industry has merged, due in particular to carbon footprint or Eco design directives increasing requirements based on life cycle assessments. To ensure fair market and reliable information, these environmental declarations should be in compliance with ISO 14025 [1]. Then, the electrical industry stakeholders, on a voluntary basis and with a consensus approach have developed a program called PEP ecopassport. This program, designed for international EEE, ensures compliance with the standard 14025 and provides the detailed rules for electrical Equipment. It carries reflections on the harmonization of environmental indicators for the benefit of downstream users, such as the association for high environmental quality of buildings. The ambition of the program is to provide a common framework to describe the performance environment with a robust LCA. This program is being piloted by a non-profit association. The role of this PEP association is to develop internationally the environmental declaration program PEP ecopassport concerning electrical, electronic and HVAC products. In this paper we develop rules for making PEP according to PEP ecopassport and we make recommendations to achieve the goal of PEP ecopassport program in the context of a medium voltage circuit breaker. (4 pages)
Robert Mcdowall - One of the best experts on this subject based on the ideXlab platform.
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Chapter 9 – Hydronic system architecture
Fundamentals of HVAC Systems, 2007Co-Authors: Robert McdowallAbstract:Publisher Summary This chapter discusses the hydronic system architecture. It considers the pumping, piping, balancing and control of water systems. It introduces the reader to the various hydronic distribution systems and some of their characteristics. The steam systems are explained here and the general operation and some of the advantages and disadvantages of steam distribution systems are detailed. The hot water heating systems are explored with the details of the main piping-layout options, pumping requirements and characteristics. The chapter presents detailed information on chilled water systems including details on the popular piping arrangements and characteristics. Lastly, the open water systems are discussed and the reader gets to know the behavior of a condenser, condenser requirements, and cooling tower operation. The chapter introduces the basic layout options for heating and cooling piping arrangements that distribute water or steam, hydronic circuits. It also provides a brief discussion of the differences in their hydronic characteristics. In each case, a flow of steam or water is distributed from either a central boiler or a chiller, the Refrigeration Equipment used to produce chilled water, to the hydronic circuits. The hydronic circuits circulate the steam or water through the building, where it loses or gains heat before returning to be re-heated or re-cooled.
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Hydronic System Architecture
Fundamentals of HVAC IP Book, 2006Co-Authors: Robert McdowallAbstract:This chapter discusses the hydronic system architecture. It considers the pumping, piping, balancing and control of water systems. It introduces the reader to the various hydronic distribution systems and some of their characteristics. The steam systems are explained here and the general operation and some of the advantages and disadvantages of steam distribution systems are detailed. The hot water heating systems are explored with the details of the main piping-layout options, pumping requirements and characteristics. The chapter presents detailed information on chilled water systems including details on the popular piping arrangements and characteristics. Lastly, the open water systems are discussed and the reader gets to know the behavior of a condenser, condenser requirements, and cooling tower operation. The chapter introduces the basic layout options for heating and cooling piping arrangements that distribute water or steam, hydronic circuits. It also provides a brief discussion of the differences in their hydronic characteristics. In each case, a flow of steam or water is distributed from either a central boiler or a chiller, the Refrigeration Equipment used to produce chilled water, to the hydronic circuits. The hydronic circuits circulate the steam or water through the building, where it loses or gains heat before returning to be re-heated or re-cooled.
Jui-sheng Chou - One of the best experts on this subject based on the ideXlab platform.
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Applying Smart Meter and Data Mining Techniques to Predict Refrigeration System Performance
The 9th International Conference on Computing and InformationTechnology (IC2IT2013), 2020Co-Authors: Jui-sheng Chou, Anh-duc PhamAbstract:This study presents six data mining techniques for prediction of coefficient of performance (COP) for Refrigeration Equipment. These techniques include artificial neural networks (ANNs), support vector machines (SVMs), classification and regression tree (CART), multiple regression (MR), generalized linear regression (GLR), and chi-squared automatic interaction detector (CHAID). Based on COP values, abnormal situation of Equipment can be evaluated for refrigerant leakage. Experimental results from cross-fold validation are compared to determine the best models. The study shows that data mining techniques can be used for accurately and efficiently predicting COP. In the liquid leakage phase, ANNs provide the best performance. In the vapor leakage phase, the best model is the GLR model. The models built in this study are effective for evaluating Refrigeration Equipment performance.
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Smart meter monitoring and data mining techniques for predicting Refrigeration system performance
Expert Systems With Applications, 2014Co-Authors: Jui-sheng ChouAbstract:A major challenge in many countries is providing sufficient energy for human beings and for supporting economic activities while minimizing social and environmental harm. This study predicted coefficient of performance (COP) for Refrigeration Equipment under varying amounts of refrigerant (R404A) with the aids of data mining (DM) techniques. The performance of artificial neural networks (ANNs), support vector machines (SVMs), classification and regression tree (CART), multiple regression (MR), generalized linear regression (GLR), and chi-squared automatic interaction detector (CHAID) were applied within DM process. After obtaining the COP value, abnormal Equipment conditions can be evaluated for refrigerant leakage. Analytical results from cross-fold validation method are compared to determine the best models. The study shows that DM techniques can be used for accurately and efficiently predicting COP. In the liquid leakage phase, ANNs provide the best performance. In the vapor leakage phase, the best model is the GLR model. Experimental results confirm that systematic analyses of model construction processes are effective for evaluating and optimizing Refrigeration Equipment performance.
Janet E L Corry - One of the best experts on this subject based on the ideXlab platform.
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microbial contamination of food Refrigeration Equipment
Journal of Food Engineering, 2004Co-Authors: J A Evans, S L Russell, Christian James, Janet E L CorryAbstract:Refrigeration systems in chilled rooms in 15 plants processing a variety of foods were studied. These included plants processing raw meat and salads, Chinese ready meals, dairy products, slicing and packing of cooked meats and catering establishments. An initial survey of total numbers of microbes at a total of 891 sites on evaporators, drip trays and chilled room walls was followed up with a more detailed examination of 336 sites with high counts, selecting for Listeria spp., coliforms, enterococci, Staphylococcus aureus and Bacillus cereus. Temperatures (particularly air on and air off, maximum and near defrost heaters) relative humidity, airflow, layout and cleaning regimes were surveyed. In general, no correlation could be found between any of the physical measurements and the numbers and types of bacteria detected. Maximum mean temperatures in the chilled rooms varied from -1 to +16.9 °C and few chilled units were regularly cleaned. Twenty five percent of sites examined had more than 105 colony-forming units per cm2, although, very few pathogens or faecal indicator bacteria were detected. Listeria spp. were not found and coliforms were found only once, in low numbers. Low numbers of S. aureus or B. cereus were present in 9 of the 15 plants, B. cereus was found on evaporators and associated drip trays in two catering plants and two plants processing cooked meat. Enterococci and S. aureus were found most frequently in a raw red meat slaughterhouse (always in low numbers). In general, microbial contamination was lower in rooms where wrapped rather than unwrapped products were stored. The type of product also affected the degree of contamination, with raw red meat and poultry or dry ingredients giving highest counts, and raw vegetables and cooked products lowest. The work demonstrated that bacteria were present on evaporator cooling coils in all factory cold rooms visited. Although evaporator-cleaning procedures were carried out in some factories as part of routine maintenance these were not shown to be effective at maintaining low levels of bacteria on evaporators. To maintain evaporator hygiene it is suggested that more regular cleaning procedures, possibly by means of automated cleansing systems, should be considered. © 2003 Elsevier Ltd. All rights reserved.