Doktora Tezleri / Phd Degree Theses

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14517/23

Browse

Browsing Doktora Tezleri / Phd Degree Theses by Department "Fen Bilimleri Enstitüsü / Mekatronik Ana Bilim Dalı / Mekatronik Mühendisliği Bilim Dalı"

Filter results by typing the first few letters
Now showing 1 - 1 of 1
  • Thumbnail Image
    Doctoral Thesis
    Elektrı̇klı̇ otobüslerı̇n ısı yönetı̇m sı̇stemı̇nı̇n ı̇yı̇leştı̇rı̇lmesı̇ ı̇çı̇n adsorpsı̇yonlu ısı pompası gelı̇ştı̇rı̇lmesı̇
    (2024) Habash, Ramı; İliş, Gamze Gediz
    Transportation in the world is one of the leading causes of CO2 emissions, pushing manufacturers to develop new technology to replace the traditional internal combustion engine with electric. Electric vehicles are the cars of the future. The authorities of most countries are encouraging the use of electric vehicles to decrease the air pollution level. In addition, the limited supply of fossil-based fuels motivates the world to go toward electric vehicles. Parallel to the world's target, this thesis proposes a cooling system for electric vehicles. Adding adsorption heat pumps to EVs has the potential to improve their performance and efficiency, making them more competitive with conventional vehicles and helping to drive the transition to a more sustainable transportation system. This thesis includes an adsorption refrigeration system as a secondary cycle to an electric bus's current vapor compression system. The main objective of this research is to increase the COP of the cooling system of the electric bus. By improving the COP value of the cooling system, the bus can have longer ranges, and the state of health of the batteries can be increased. In this thesis, the adsorption chiller is considered, and the waste of the synchronous motor of the electric bus is used as an input energy of the adsorption chiller. The novel pair is proposed as silica gel RD/ethanol for the adsorption chiller in the present investigation. This pair gives us the flexibility to use the low-temperature heat source of the motor to generate an extra cooling effect. The silica gel RD/ethanol can be regenerated by the waste heat of the synchronous motor. In the desorption process, the low-temperature motor coolant can be used in the proposed adsorption chiller. Additionally, this system can enhance efficiency while employing sustainable refrigerants. It would be more rational and practicable to increase the COP of the existing vapor compression cycle by adding the cycle of the adsorption chiller rather than redesigning a heat pump for the electric vehicle. The hybrid system has two independent refrigeration cycles: a current vapor compression cooling cycle of the electric vehicle using R134a as a refrigerant and the adsorption heat pump cycle using a silica gel RD/ethanol pair. A one-dimensional validated Matlab/Simulink code is written to simulate the results of the adsorption chiller for different conditions. A synchronous motor model is developed to understand the potential of the motor's waste heat of the electric bus. The e-magnetic model of the synchronous motor is developed using Motor-CAD to simulate the motor coolant temperature. The e-magnetic model is validated with the manufacturer's data, and the thermal model is developed and validated. The validated thermal model of the motor is used to generate equation sets to predict the temperature of the motor's coolant as a waste heat source of the adsorption chiller at different Vdc and rpm values along the process. A Matlab/Simulink code is written for different motor conditions using these generated equations. The Matlab/Simulink code of the motor and the Matlab/Simulink code of the adsorption chiller are combined. For different Vdc and rpm conditions, the calculated coolant temperature of the motor is found and used as an input temperature value of the desorption process. The subcooling effect causes an extra cooling capacity by decreasing the enthalpy value of the inlet evaporator condition of the electric bus's existing vapor compression cooling cycle. The silica gel/ethanol adsorption chiller cooling capacity is optimized, and by using the cooling generated by the adsorption chiller, which does not use any electricity from the bus, the COP values of the existing cooling system of the electric bus are achieved to increase to around 10 %. The results showed us a promising system that can be used to achieve long ranges and healthy battery conditions for electric heavy-duty vehicles.