Effect of Stack Positioning on a Temperature Difference of Thermo Acoustic Refrigerator

2012 ◽  
Vol 3 (5) ◽  
pp. 93-95
Author(s):  
Kartik M Trivedi ◽  
WCET Journal ◽  
2019 ◽  
pp. 18-22
Author(s):  
Hiske Smart ◽  
Eman Al Al Jahmi ◽  
Ebrahim Buhiji ◽  
Sally-Anne Smart

Industrial infrared thermometry devices are large and, despite being less expensive than the current gold standard Exergen Dermatemp medical infrared thermometer, are still not affordable enough to ensure unrestricted and consistent use of this assessment modality in regular wound-related day-to-day practice. An increased skin surface temperature differentiation of 3°F associated with a wound has a positive predictive ability to detect deep or surrounding wound infection. This study hypothesised that inexpensive, pen- or pocket-sized, no-touch surface infrared thermometry devices will be equal in ability to detect a 3oF increased skin temperature compared to the Exergen Dermatemp infrared device and be reliable in the hands of any wound assessor. The odds of the control and other thermometers to detect a 3oF temperature difference, irrespective of the raters, were achieved in all five of the mini thermometers tested, with a correct temperature difference prediction that occurred in 90.933% of the times (odds determined 9/10). As a result of this study mini, no-touch infrared thermometry, to detect a 3oF temperature difference in wound assessment to determine tendency, could be implemented into primary health care clinics, rural clinics, day-to-day hospital practice and standard outpatients departments at a small financial cost, regardless of which thermometer is put to use.


Author(s):  
Konstantin V. Agapov ◽  
Dmitriy O. Dunikov ◽  
Kirill D. Kuzmin ◽  
Evgeniy V. Stoyanov

In this publication, in addition to focusing on the engineering component in creating our own test bench for trying various modes and the overall performance of solid polymer fuel cells with electric power of more than 2 kW, the features of the result of the operation of a liquid-cooled fuel cell in the field of heat transfer are displayed. It is known that its performance and service life depend on a properly tuned water and thermal balance of the fuel cell. The problem area is described in the insufficient moisture content of the supplied air to the fuel cell and the excess heat in the fuel cell. In this case, the negative consequence is that additional resistance to the rate of the electrochemical reaction is created, as a result of which the generated power decreases. A possible way to solve this problem is proposed: so, according to the heat balance equation, by increasing the temperature difference between the incoming and outgoing heat carrier, more heat energy can be removed. The temperature difference was achieved using a water-air radiator. The increased removal of thermal energy allowed the condensation of part of the moisture inside the fuel cell, maintaining the humidity and conductivity of the membrane, but not allowing flooding of the channels with liquid water, which otherwise could lead to a decrease in performance. During the tests, it was possible to increase the removed power by 321 w, which is 8.4% in excess of the maximum power. Based on the obtained experimental results, dependencies were constructed that are expressed by the current-voltage characteristic, power curve, the amount of heat removed by the water from the fuel cell, and a graph of the change in water temperature at the inlet and outlet of the fuel cell at various stages of operation.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1503
Author(s):  
Minsu Kim ◽  
Hongmyeong Kim ◽  
Jae Hak Jung

Various equations are being developed and applied to predict photovoltaic (PV) module generation. Currently, quite diverse methods for predicting module generation are available, with most equations showing accuracy with ≤5% error. However, the accuracy can be determined only when the module temperature and the value of irradiation that reaches the module surface are precisely known. The prediction accuracy of outdoor generation is actually extremely low, as the method for predicting outdoor module temperature has extremely low accuracy. The change in module temperature cannot be predicted accurately because of the real-time change of irradiation and air temperature outdoors. Calculations using conventional equations from other studies show a mean error of temperature difference of 4.23 °C. In this study, an equation was developed and verified that can predict the precise module temperature up to 1.64 °C, based on the experimental data obtained after installing an actual outdoor module.


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