Performance Characteristics of PTC Elements for an Electric Vehicle Heating System
A high-voltage positive temperature coefficient (PTC) heater has a simple structure and a swift response. Therefore, for cabin heating in electric vehicles (EVs), such heaters are used either on their own or with a heat pump system. In this study, the sintering process in the manufacturing of PTC elements for an EV heating system was improved to enhance surface uniformity. The electrode production process entailing thin-film sputtering deposition was applied to ensure the high heating performance of PTC elements and reduce the electrode thickness. The allowable voltage and surface heat temperature of the high-voltage PTC elements with thin-film electrodes were 800 V and 172 °C, respectively. The electrode layer thickness was uniform at approximately 3.8 μm or less, approximately 69% less electrode materials were required compared to that before process improvement. Furthermore, a heater for the EV heating system was manufactured using the developed high-voltage PTC elements to verify performance and reliability.
Performance characteristics of a dual-evaporator heat pump system for effective dehumidifying and heating of a cabin in electric vehicles
In electric vehicles, air-conditioning (AC) units and electric heaters have been used for dehumidifying and heating the cabin. However, the air heating process in the electric heater causes higher power consumption due to a lower air temperature entering the electric heater from the sensible cooling in the humidifying process. In this study, a heat pump (HP) and a dual-evaporator heat pump (DHP) combined with a heater are proposed as effective dehumidifying and heating units using waste heat recovery from the dehumidifying process. The performances of the AC, HP, and DHP systems were measured and compared by varying the indoor air wet bulb temperature and compressor speed ratio. Generally, the HP and DHP systems showed superior performance to the conventional AC system in the dehumidifying and heating operation. At the indoor air wet bulb temperature of 13°C, the DHP system showed 53% and 62% higher specific moisture extraction rate and COP, respectively, than the HP system.
Global Islamic Politics
1. Introduction to Islam and Islamic Revivals. 2. Islam: A Vehicle for Political Action. 3. The Muslim Fundamentalists. 4. The Muslim Traditionalists. 5. The Muslim Modernists. 6. The Muslim Pragmatists. 7. Failure of Secular Ideologies and Developmental Crises. 8. Islamic Revivalism in the Arab-Israeli Context. 9. OPEC, OIC, and Islamic Politics. 10. The Islamic Revolution in Iran. 11. Islamic Revival in Central Asia. 12. Conclusion. Glossary of Islamic Terms.