Energy Analysis Techniques

Author(s):  
Clive Beggs
2018 ◽  
Vol 10 (12) ◽  
pp. 4448 ◽  
Author(s):  
Samuel Domínguez-Amarillo ◽  
Jesica Fernández-Agüera ◽  
Juan Sendra ◽  
Susan Roaf

Although energy analysis techniques can contribute to substantial energy savings in housing stock retrofitting operations, the outcomes often deviate significantly from the predicted results, which tend to overestimate potential savings by overestimating the starting energy baselines, particularly in southern Europe. This deviation can be largely attributed to occupant practice relating to the use of air conditioning facilities and the temperatures at which occupants feel comfortable. The patterns observed differed widely from standard values. In this study environmental variables, primarily indoor air temperature both with and without HVAC, were monitored in occupied dwellings for a full year. The data gathered were supplemented with surveys on occupants’ temperature-related behaviour to define comfort patterns. The findings show that the standards in place are not consistent with actual comfort-accepted patterns in medium- to low-income housing in southern Spain, where energy consumption was observed to be lower than expected, mostly because occupants endure unsuitable, even unhealthy, conditions over long periods of time. A new user profile, better adjusted to practice in southern Europe, particularly in social housing, is proposed to reflect the current situation.


2002 ◽  
Vol 459 ◽  
pp. 245-276 ◽  
Author(s):  
MANUEL GAMERO-CASTAÑO ◽  
VLADIMIR HRUBY

We use time-of-flight and energy analysis techniques to measure in a vacuum the charge, specific charge and stopping potential of primary and satellite droplets generated by electrosprays of tributyl phosphate solutions. This information, of interest in itself, is subsequently analysed to obtain the following relevant parameters of the jet emanating from the Taylor cone: the velocity of the fluid at the breakup point, the voltage difference between the liquid cone and jet breakup location, and the most probable wavelength for varicose breakup. A large fraction of the electrospray needle voltage is used to accelerate the jet. Indeed, for the solutions of lowest electrical conductivities studied here, the voltage difference between electrospray needle and jet breakup location becomes approximately 90% of the needle voltage. In addition, the pressure of the jet fluid at the breakup point is negligible compared to its specific kinetic energy. The specific charge distribution function of the main droplets produced in the varicose breakup is remarkably narrow. Hence, the limiting and commonly accepted case of varicose breakup at constant electric potential is not consistent with this experimental observation. On the other hand, a scenario in which the electric charge is bound to the jet surface seems to be a good approximation to simulate the effect of charge on capillary breakup. It is also found that the effect of viscosity on the formation of droplets is paramount in electrosprays of moderate and high electrical conductivity. We expect that these measurements will guide the analytical modelling of cone-jets.


2020 ◽  
Vol 17 (1 Jan-Jun) ◽  
pp. 19
Author(s):  
C. Álvarez-Macías ◽  
L. Salgado-Conrado ◽  
J. De la Cuz Canul ◽  
And M. Rivero Corona

In this paper, we present a comparison of classical theory with video analysis techniques to teach kinetic and potential energy of a device with a boomerang effect as an observable and measurable concept. The device can store energy through an elastic band when it rolls downan inclined plane and can release the energy when it rolls on a horizontal surface; hence, the name Boomerang. In theoretical terms, the details of energy charge and discharge processes are analysed with Newton’s laws and Lagrangian method. The experimental results were recorded with cell phone cameras and processed with an open-source video analysis software, called ’Tracker’. The comparison shows relevant concepts about kinetic and potential energy, which can help the student to overcome some of the typical student misconceptions.


2017 ◽  
Vol 77 (12) ◽  
Author(s):  
C. Alduino ◽  
K. Alfonso ◽  
D. R. Artusa ◽  
F. T. Avignone ◽  
O. Azzolini ◽  
...  

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