scholarly journals Indoor distribution transformers oil temperature prediction using new electro-thermal resistance model and normal cyclic overloading strategy: an experimental case study

2020 ◽  
Vol 14 (24) ◽  
pp. 5792-5803 ◽  
Author(s):  
Ali Asghar Taheri ◽  
Ali Abdali ◽  
Abbas Rabiee
2020 ◽  
Vol 15 ◽  
pp. 155892501990083
Author(s):  
Xintong Li ◽  
Honglian Cong ◽  
Zhe Gao ◽  
Zhijia Dong

In this article, thermal resistance test and water vapor resistance test were experimented to obtain data of heat and humidity performance. Canonical correlation analysis was used on determining influence of basic fabric parameters on heat and humidity performance. Thermal resistance model and water vapor resistance model were established with a three-layered feedforward-type neural network. For the generalization of the network and the difficulty of determining the optimal network structure, trainbr was chosen as training algorithm to find the relationship between input factors and output data. After training and verification, the number of hidden layer neurons in the thermal resistance model was 12, and the error reached 10−3. In the water vapor resistance model, the number of hidden layer neurons was 10, and the error reached 10−3.


2016 ◽  
Vol 9 (12) ◽  
pp. 4491-4519 ◽  
Author(s):  
Aurélien Gallice ◽  
Mathias Bavay ◽  
Tristan Brauchli ◽  
Francesco Comola ◽  
Michael Lehning ◽  
...  

Abstract. Climate change is expected to strongly impact the hydrological and thermal regimes of Alpine rivers within the coming decades. In this context, the development of hydrological models accounting for the specific dynamics of Alpine catchments appears as one of the promising approaches to reduce our uncertainty of future mountain hydrology. This paper describes the improvements brought to StreamFlow, an existing model for hydrological and stream temperature prediction built as an external extension to the physically based snow model Alpine3D. StreamFlow's source code has been entirely written anew, taking advantage of object-oriented programming to significantly improve its structure and ease the implementation of future developments. The source code is now publicly available online, along with a complete documentation. A special emphasis has been put on modularity during the re-implementation of StreamFlow, so that many model aspects can be represented using different alternatives. For example, several options are now available to model the advection of water within the stream. This allows for an easy and fast comparison between different approaches and helps in defining more reliable uncertainty estimates of the model forecasts. In particular, a case study in a Swiss Alpine catchment reveals that the stream temperature predictions are particularly sensitive to the approach used to model the temperature of subsurface flow, a fact which has been poorly reported in the literature to date. Based on the case study, StreamFlow is shown to reproduce hourly mean discharge with a Nash–Sutcliffe efficiency (NSE) of 0.82 and hourly mean temperature with a NSE of 0.78.


Author(s):  
James Muriuki ◽  
Christopher M. Muriithi ◽  
Living Ngoo ◽  
George N. Nyakoe

2019 ◽  
Vol 887 ◽  
pp. 467-474
Author(s):  
Radoslav Ponechal ◽  
Renáta Korenková ◽  
Daniela Štaffenová

This study solves a problem of the dynamic thermal performance of the residential attic space in moderate climatic zone. Heat loss into the attic space is difficult to be accurately determined by the quasi-stationary method. It depends on the thermal resistance of the ceiling, thermal resistance of the roof, ventilation characteristics and other details, such as the solar absorption of the roofing material or roof orientation. The paper presents results of some parametric simulative calculations, which were calibrated with measurements of air temperature in the attic space during the summer, winter and transitional season. It compares the mean air temperature in the ventilated and non-ventilated attics. The difference between the use of bright and dark color of the roof cover is also compared. An alternative with half thickness of thermal insulation was also simulated. Based on measurements and then the simulation the adjustment factor adjustment factor for heat transfer coefficient was quantified..


Author(s):  
Y Rasihhan ◽  
F J Wallace

A simple, effective and computationally economical piston-liner thermal resistance model for diesel engine simulation is described. In the model, the detailed shape of the piston and its axial movement and interaction with liner nodes are all taken into account. An imaginary node within the piston provides the necessary temperature difference between the piston and the liner nodes for conductive heat transfer, which is expected to reverse its direction with liner insulation. In the liner, an axially symmetric two-dimensional heat-transfer model is used. Later the piston-liner model is tuned for the experimental single cylinder, direct injection, Petter PH 1W engine used at Bath University, against the experimental piston temperature and liner temperature distribution.


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