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Unfavorable climates, fatigue, safety & deprived sleep of driver’s leads to use of AC system for their quick thermal comfort during night with engine ON. This scenario is very critical from a human’s safety & vehicle functionality point of view. This also consumes an additional 10-15% of fuel requirements in AC running conditions. So, to address the social problems of driver’s sleep and pollution-free environment by reducing the use of fossil fuels, there is a need for alternative techniques for air cooling which work during engine OFF condition. Various alternative options for air cooling have been reviewed. Accordingly, the packaging flexibility of phase change material (PCM) technology makes it easy to implement, yet effective usage of large quantity stored PCM, needs optimization. This paper proposes a design of a hybrid air conditioning system for sleeper commercial vehicles using a combined conventional compression and phase change material.

Commercial electric vehicle air conditioning system keeps occupants comfortable, but at the expense of the energy used from the battery of vehicle. Passengers around the world are increasingly requesting buses with HVAC/AC capabilities. There is a need to optimise current air conditioning systems taking into account packaging, cost, and performance limits due to the rising demand for cooling and heating globally. Major elements contributing to heat ingress are traction motor, front firewall, windshield & side glasses and bus body parts. These elements contribute to the bus’s poor cooling and lack of passenger comfort. This topic refers to the reduction of the heat ingress through usage of different glass technology like IR Cut & solar green glass with different types of coating.

In an automotive air conditioning system, evaporator is well designed for effective heat transfer between refrigerant and air flowing over the evaporator. This cold and dehumidified air obtained at evaporator is then supplied to passenger cabin. There are various parameters like air flow over evaporator, ambient temperature, humidity condition and condensate drain mechanism which can cause frost formation over the evaporator core. This study presents the probable causes of frost formation and their effects on the performance of evaporator and thus affecting overall performances of the automotive air conditioning system. In this study effect of variation in four major independent factors such as poor response of thermistor, undercharged refrigerant system and overcharged refrigerant system, drop in air flow by blower due to clogged air-filter, and also the effect of type of compressor has been studied.

AC system provides the human comfort inside the cabin of a vehicle but at the expense of consumption of energy from the vehicle. On a global perspective for the bus segment, there is an increased demand for cooling in tropical countries. Optimization needs to be done in existing AC systems w.r.t packaging, cost & performance constraints. Major elements contributing to heat ingress are engine hood, front firewall, windshield & side glasses and bus body parts. Due to these reasons inadequate passenger comfort and poor cool down performance of the vehicle is observed. This paper refers to the reduction of heat ingress through different DOE (Design of Experiment) in the area of design & validation for duct & vent layout, insulation, glass & paint technology, evaporator blowers. The new duct design has been evaluated using a CFD tool by varying various parameters to generate desired output. The integrated use of the modifications was found significant improvement at vehicle level.

With the passage of the Kigali Amendment to the Montreal Protocol, HFC-134a refrigerant will be phased down in all markets worldwide, including those where automotive companies have been slow to embrace HFO-1234yf. Engineers are currently being challenged to design MAC systems using alternate low GWP refrigerants that are allowed by regulations, and are simultaneously cost-effective to manufacture, energy efficient, safe, reliable, affordable for consumers, and also suitable in electrified vehicles.