Entity

Time filter

Source Type


Cvetkovski C.G.,University of Windsor | Reitsma S.,54 Energy | Bolisetti T.,University of Windsor | Ting D.S.K.,University of Windsor
Sustainable Energy Technologies and Assessments | Year: 2015

The performance of ground source and surface water heat pumps relies greatly on the heat transfer efficiency throughout the ground loop configuration. Typically these are vertical loops and consist of two pipes connected by a U-Bend at the bottom end. The U-Bend section generates vortical structures and turbulence, enhancing the heat transfer process. Two parameters that affect the flow turbulence and vortical structures are the Reynolds number and the Dean number. The isolated effects of the Reynolds and the Dean number are studied. It was found that while the Reynolds number has the greater effect on the average heat flux of the system; the Dean number's influence on the heat flux is greater in the curved section of the pipe. The large vortex structures can last for many diameters downstream of the U-Bend. For the high Reynolds number flow it was shown that increasing the Dean number significantly enhances the longevity of vortex structures. This indicates that enhancing the Dean number in an already turbulent flow will further augment the heat transfer process. © 2015 Elsevier Ltd. Source


Cayci H.,54 Energy
Metrology and Measurement Systems | Year: 2011

A practical method with high accuracy in generation and application of error values for calibration of current transformer test sets is described. A PC-controlled three-phase power source with a standard wattmeter is used for generating the nominal and error test currents while an electronically compensated current comparator is used to provide summation and subtraction of them, precisely. With this method, any ratio error and phase displacement values could be generated automatically and nominal and test currents could be grounded on the test set safely. Because of its high accurate ratio and phase error generating capability, any type of test set regardless of its operating principles could be calibrated. © 2011 Polish Academy of Sciences. Source


Dehkordi S.E.,University of Western Ontario | Schincariol R.A.,University of Western Ontario | Reitsma S.,54 Energy
Renewable Energy | Year: 2015

A major attribute that affects a borehole heat exchanger's performance is its thermal resistance. Internal and borehole thermal resistances, among other factors, depend on the location of pipes in relation to each other and the borehole wall. The internal borehole resistance defines the short-circuit effect between the pipes, and the borehole thermal resistance is an indication of heat exchange ability with the ground. Effective borehole resistance depends on both abovementioned thermal resistance components, and describes the thermal efficiency of the BHE. It is found that the temperatures of the loop fluid and borehole wall respectively are sensitive to pipe separation and borehole diameter. This study confirms that proximity of the pipes to the borehole wall is more important than the pipe separation in reducing the total borehole resistance (i.e. temperature difference between loop fluid and borehole wall). Hence, a tight borehole design, with little spacing between the down-hole pipes, and the borehole wall, is proposed here. In such a design, a narrow borehole diameter is used with no pipe spacers. Through numerical modelling and thermal response testing, this study shows that a tight borehole heat exchanger could provide an acceptable thermal performance while optimizing the drilling and grouting volumes. © 2015 Elsevier Ltd. Source


Alessandrini S.,54 Energy | Ferrero E.,University of Piemonte Orientale
International Journal of Environment and Pollution | Year: 2011

In this work, a Lagrangian particle model able to account for simple chemical reactions between NO and O 3 has been improved to consider the photolysis of NO 2. A system of chemical equations is numerically solved on a Eulerian grid, while the particle trajectories are moved in a Lagrangian frame. The NO x emissions of a power plant in real atmosphere, situated in a complex topography environment, have been considered as a test case. The simulated episodes refer to the diurnal time, when the ultraviolet radiation activates the NO 2. Comparisons between NO/NO 2's concentrations ratio are presented in terms of scatter plots and statistical indexes analysis. Copyright © 2011 Inderscience Enterprises Ltd. Source


Izutsu K.,Nagoya University | Takano M.,Nagoya University | Furuya S.,University of Aalborg | Iida T.,54 Energy
Renewable Energy | Year: 2012

This paper focuses on the critical actors (herein called Driving Actors) and their activities to promote sustainable energy policies and businesses in cases where renewable energy facilities are gradually installed in a local area by changes in lifestyle from one based on fossil fuels to a sustainable one. This paper aims to 1) evaluate activity to promote renewable energy in local community using analytical approaches as an iterative approach and stakeholder analysis, and 2) to propose an analytical framework for the RE implementation process and to describe the important roles of the Driving Actors. We investigated the case of Bizen city in Japan by participant observations. Consequently, Driving Actors are responsible for encouraging RE implementation in the local area. They coordinate and run the RE (Renewable Energy) program to gain experience and know-how as well as create a business scheme, which has business risk due to the absence of effective policies by the national government during the middle phase to promote local success of RE. If the national government implements effective policies to disseminate RE facilities during the middle phase, then the Takeoff phase is ascertained and existing big companies and financial organizations would begin to participate RE businesses. On the other hand, if the national government does not change its policy, Driving Actors must initiate a creative RE project using their expertise in the middle phase. © 2011 Elsevier Ltd. Source

Discover hidden collaborations