Thermal inertiality of the air in the public transport cabin with conditioning system

Abstract

In modern conditions, energy efficiency contributes to increasing competitiveness in the domestic and international markets of transport services. For Ukraine, the efficient use of fuel and energy resources is one of the most essential tasks that ensure the country's energy security and energy independence. The specifics of the operating conditions of rolling stock on urban bus routes in the warm season with air conditioning determine the number of requirements for the design parameters of the vehicle itself and for systems that provide the proper microclimate during the transport process. A characteristic feature of the microclimate in the interiors of city buses is the instability of its parameters since the temperature of the air and facing structures during the day can vary up to 10 C or more. It was presented in the work the decision with regards to the check-up of thermal inertiality of the city bus cabin air for determining the relevance of reviewing the usage of the certain power conditioner as a factor of power consumption reduction. When choosing temperature control systems in the passenger compartment, the real heat inertia of the indirect flow, which is passed through the passenger compartment of the bus by air conditioning, is taken into account. On purpose of increasing energy efficiency of the public transport in the warm season of the year while working with the conditioner it was considered the method of energy saving via reviewing the construction of the cabin interior and predicted speed of its cooling.  It was obtained the results of the conducted exploitation tests of the microclimate in the public transport on the city routes at the temperature of the environment from +25 up to +34˚С. It was established that absorption of solar energy and thermal conductivity are the dominant factors of the bus construction, and thermal inertiality of the air is the important parameter of comfort and it favors loading reduction while warming and cooling.

Key words: city bus, bus cabin, thermal inertiality, thermal balance, comfortable conditions, temperature environment.