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eng Rationalization of cooling water consumption in extraction system B-811 LSV
Budžaki, Sandra; Čačić, F.; Miljić, G.
Water (drinkable) is vital natural resource, and during the last few decades it is imperative to reduce its needless consumption. Extraction devices are known for their significant cooling water consumption and laboratory scale devices mainly use drinkable water. Aim of this paper was rationalization of cooling water consumption during extractions in universal extraction system B-811 LSV by recirculating cooling water trough cooling tower. In order to obtain the data for cooling tower design, measurements of cooling water flow, inlet and outlet...
Hrčak ID: 131749


eng Analysis of Cooling Water Systems in a Petroleum Refinery
Matijašević, Lj.; Vučković, A.; Dejanović, I.
An important area in process integration is the development of methodologies to minimize water and energy use in industry. More than 20 % of the energy consumption in industry is associated with cooling and heating water. This paper presents analysis and optimization of a re-circulating cooling water system, with the aim to satisfy any supply conditions for the cooling tower. The part of the atmospheric crude oil distillation unit was chosen for analysis and synthesis of cooling water systems by the Kim and Smith design (KSD) method. The load o...
Hrčak ID: 132454


eng Chilled Water Storage Feasibility with District Cooling Chiller in Tropical Environment
Al Quabeh, Hilal; Saab, Roba; Ali, Mohamed I. H.
The difficulties of efficiently operating a chiller cooling system are manifest in the high-energy consumption under partial-cooling loads. The performance of a chiller cooling system declines when operating away from the optimal design conditions, which is typically 75% of chiller capacity. One pathway has been found to overcome this problem using multiple smaller chillers within the same chiller plant, accompanied by a smart control system that is designed and constructed based on the cooling demand profile. Thermal energy storage integration...
Hrčak ID: 226026


eng Utilization of dissipated heat of power transformers
Trbusic, Mislav; Marusa, Robert; Pihler, Jože; Hamler, Anton
Transformers Magazine Vol. 6, No. 5, 2019
The aim of the article is to provide the reader with the basic concept of the transformer’s heat utilization where a proposed technical solution anticipates the installation of an additional oil-water heat exchanger (ODWF) in the transformer's cooling system. An increase in the transformer’s cooling capacity lowers the oil temperature and reduces the transformer’s loss of life expectancy. In order to estimate the transformer’s oil temperature profile, as well as the heat power potential at the water side of the ODWF cooler, a numerical investig...
Hrčak ID: 228369


eng The importance of thermal design to transformer lifetime
Jarman, Paul
Transformers Magazine Vol. 7, No. 2, 2020
According to the evidence gathered from many large scrapped transformers over the years, some transformers seem to have aged thermally at much higher rates than others. This discrepancy cannot always be ascribed to the operating conditions, and it has become clear that some units have much higher internal temperatures and consequently more rapid ageing than expected. This column explores some of the potential reasons for this, some of the research that has been carried out and some of the considerations and techniques that can be applied to avo...
Hrčak ID: 236746


eng Variable-speed air-forced cooler technology
Siffring, Wolfgang
Transformers Magazine Vol. 3, No. 2, 2016
Advanced air coolers are able to cool transformer oil more efficiently than older systems. Replacement or expansion of cooling plants by a new solution can lead to reduction of oil temperatures by several degrees and have a positive influence on the service lifetimes of oil and therefore transformers. Or, conversely, better coolers can – at the same oil temperatures – enhance the maximum performance of a transformer or allow it to operate at a higher average load. The upgrade or expansion of a cooling system in some cases can eliminate the need...
Hrčak ID: 167665


eng Thermal Designing and Building Transformers for Use with Viscous Fluids
Sundin, David
Transformers Magazine Vol. 1, No. 2, 2014
Since the 1970s, transformers have used special fre resistant fluids that are often more viscous than standard transformer oils. This article looks at the different types of fre resistant oils that have been used, and the changes in transformer cooling design that have been made to accommodate their higher viscosity
Hrčak ID: 186724


hrv Simulacija hlađenja hibridno izrađenog alata za injekcijsko prešanje polimera s prilagođenim rashladnim kanalima
eng Cooling simulation of conformal cooling injection mould insert produced by hybrid manufacturing
Homar, David; Čerče, Luka; Kopač, Janez
Tehnički vjesnik Vol. 24, No. 4, 2017
Hlađenje alata za injekcijsko prešanje polimera izrađenog obradom odvajanjem čestica ima ograničenja, jer su kanali za hlađenje sastavljeni od uobičajenih ravnih rupa. Aditivnom tehnologijom mogu se izraditi rashladni kanali koji su prilagođeni kalupnoj šupljini. Ta vrsta rashladnih kanala naziva se konformni rashladni kanali. Konformni rashladni kanali mogu znatno smanjiti vrijeme ciklusa proizvodnje pri injekcijskom prešanju i znatno poboljšati kvalitetu proizvoda. U ovom istraživanju su dizajnirani i analizirani konformni rashladni kanali ka...
Hrčak ID: 185499


eng Dilatometric analysis of cooling curves for high strength steel X155CrMoV12
Krbaťa, M.; Majerik, J.; Barenyi, I.; Eckert, M.; Čep, R.; Sedlak, J.; Samardžić, I.
Metalurgija Vol. 61, No. 1, 2022
The article deals with phase transformations and austenitizing behavior of the X155CrMoV12 tool steel. Dilatation analyses of a series of samples were performed at various cooling rates, chosen in the range from 10 °C/s to 0,1°C/s. Acquired experimental data were used for evaluation of dilatometric curves in order to map the temperature ranges of phase transformations of the austenite to pearlite, bainite or martensite. All experimental samples from dilatometric analyses were then subjected to microstructural analyses and hardness measurements...
Hrčak ID: 262416


eng A Control Configuration for Temperature Control of a Cooling Crystallizer Based on a Two-level-model Predictive Control
Mortazavi-Manesh, S.; Svrcek, W. Y.
A two-level-model-predictive-control configuration is proposed that incorporates the dynamics of a crystallizer unit in order to track the required temperature cooling trajectory. Dynamic matrix control has been successfully used to control the crystallizer temperature by manipulating both heater and cooler units. The performance of the model predictive control has been evaluated by comparing its performance to a conventional PI control configuration. The results demonstrated excellent and consistent cooling temperature tracking performance by...
Hrčak ID: 49480