In the technical field the energy balances are derived from the 1st thermodynamic law, which covers merely the instantaneous quantitative aspects of heat flows. In terms of energy conservation law these balances are expressed in the form of constant sums of exergy and anergy. And that is why they cannot, or can only to a very limited extent, be used to define the transformation of part of the energy (exergy) to the less valuable energy (anergy). Using the 2nd thermodynamic law we have a chance to trace the energy transformation through entropy, a quality indicator of every heat process and an accompanying symptom of process irreversibility. The plate air-to-air heat exchanger, whose exergy analysis is in the spotlight of our interest, operates, in terms of the laws above, in irreversible changes, while the change of entropy induced by the heat flows depends on the construction and surface of the heat exchange areas. The article analyses the influence of air inlet temperatures on the thermal exergy efficiencies of the heat exchanger and the heat loss exergy. Assessment is based on extensive measurements of the temperature, humidity and flow rate of the heated and cooled air in the plate heat exchanger. Both ...
The aim of this study was analyze of the efficiency of the natural ventilation in the horse stable and an indication of opportunities to improve its operation. The study was conducted in Glinik Zaborowski in the winter. The scope of the research included measurements of air velocity with opened and closed windows and gates. Based on the results of the measurements and observations, it was found that the efficiency of the ventilation was very low. Average values of the air flow ranged from 0.06 m•s-1 to 0.12 m•s-1. These values were lower than the minimum air velocity recommended. The main reasons for very low air velocity in the horse stable was incorrect location and the wrong design solutions, among which the most important were: the lack of ventilation aparatures and abnormal direction of opening windows ...
