Pamela Koszut, Jarosław Müller
Wydział Inżynierii Środowiska i Energetyki, Politechnika Krakowska
Ciepłownictwo Ogrzewnictwo Wentylacja, 2026 (5), 48-53, DOI: https://doi.org/10.65545/COW.2026.05.06
Keywords: fair conditioning, ventilation, outdoor air parameters, Mollier diagram, air treatment processes
Abstract
Ensuring comfortable conditions in public buildings is one of the main goals of air conditioning. The parameters that primarily determine the feeling of comfort are temperature and relative humidity. The air handling unit (AHU) in the air treatment system regulates these conditions, but the operation of this part of the air conditioning system is determined by the condition of the air supplied to the AHU. Design outdoor air conditions presented in the literature refer to the conditions characteristic of a given climate zone, meaning they are statistical average values. In design practice, these values are treated as a single point on the Mollier diagram, representing the most unfavourable outdoor conditions that the system should handle. In practice, outdoor air conditions vary over time and, in some cases, significantly deviate from the design conditions. The task of the AHU automation system is to adapt the treatment processes to the varying parameters of the air entering the system.
This work analyses the impact of variable outdoor air parameters on the treatment processes in the air conditioning system of an auditorium. The study addressed the design of an installation in which a ventilation and air conditioning system was designed for a hall with air supply from under the seats and exhaust through the ceiling. The analysis was conducted based on meteorological data covering the facility’s operational period and illustrated with a Mollier diagram. Characteristic points and zones where air parameters most frequently occur were identified, and then the processes of change in the air handling unit’s devices, such as the heat recovery exchanger, cooler, heater, and mixing chamber, were assessed. The study demonstrated the significant impact of variability in external conditions on air conditioning processes and the need to consider more than one calculation point when designing air conditioning systems.
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Bibliography
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