Akademik Veri Yönetim Sistemi
7. ENERJİ VERİMLİLİĞİ KONGRESİ, Kocaeli, Türkiye, 22 Kasım 2025, ss.49-63, (Tam Metin Bildiri)
ABSTRACT
In recent years, the
increasing impacts of global warming and environmental pollution have
accelerated the development of zero-emission transportation technologies. Fuel
Cell Electric Vehicles (FCEVs) are emerging as a promising alternative due to
their high efficiency and lack of harmful emissions. However, approximately
40–50% of the energy produced by fuel cells is lost as waste heat. %. The aim
of this study is to enhance overall energy efficiency by recovering waste heat
generated in the fuel cell cooling system through cabin heating and Organic
Rankine Cycle (ORC).In this study, a one-dimensional Proton Exchange Membrane
(PEM) fuel cell bus model created using Siemens Simcenter Amesim software was
analyzed under EPA Highway and FTP-72 (UDDS) driving cycles. Simulation
analyses revealed that the fuel cell efficiency ranged between 45–50%. Under
urban driving conditions, the fuel cell produced an average power of 39 kW,
feeding the battery and increasing the State Of Charge (SOC) by 19%. In highway
driving conditions, it operated in parallel with the battery at an average
power of 59 kW, resulting in a SOC decrease of 28.66 In both scenarios, similar
amounts of heat were transferred to ORC; cycle efficiencies were calculated as 7.7%
and 6.8%, respectively. The results obtained demonstrate the potential for ORC
integration to enhance energy recovery and heating efficiency in zero-emission
city buses. In cabin heating scenarios, using waste heat resulted in 40–50%
energy savings depending on ambient temperature, significantly reducing the
need for electric heaters. During the FTP-72 driving cycle (a 1,370-second
cycle corresponding to approximately 22.3 minutes), the fuel cell cooling
system released 10 kWh of energy to the environment. Under winter operating
conditions, this bus requires an average of 12 kWh of thermal energy per hour
for cabin heating, and the energy discharged through cooling is more than
sufficient to meet this heating demand. Consequently, substantial energy
savings can be achieved.
Keywords: Fuel Cell Electric Bus,
Organic Rankine Cycle, Waste Heat Recovery, Energy Efficiency.