Aman Mohd Ihsan Mamat

Steady - State potential energy recovery modeling of an open cathode PEM fuel cell vehicle

Waste heat recovery in automotive engineering is part of the sustainable energy effort to optimize energy utilization. For vehicles running on hydrogen fuel cells, the potential of heat recovery is perceived to be limited due to the low quality energy generated from the fuel cell stack. It has been established in fuel cell operation that increasing the inlet hydrogen temperature improves the conversion efficiency through higher kinetic reaction rates. A fuel cell power plant for a mini vehicle that will be competing in Shell Eco Marathon Asia 2014 was studied to identify the potential energy recovery limits for an improved power plant design with regenerative hydrogen pre-heater. Using modeling approach for fuel cell power generation and efficiency relationships, the first-order waste energy potential was identified based on test bench studies on the electrical and thermal power relationship of the fuel cell stack performance. The corresponding result is then mapped to a driving cycle to investigate the thermal power generated during the race in both aggressive and passive driving cycle. The energy recovery potential for 4 laps course under aggressive and passive driving cycle are 529 kJ and 501.8 kJ consecutively. The mean thermal powers are 485 W and 410 W respectively which is the reference energy for extended heat exchanger design purposes.

Thermal performance of Al2O3 in water - Ethylene glycol nanofluid mixture as cooling medium in mini channel

Continuous need for an optimum conversion efficiency of a Proton Exchange Membrane Fuel Cell (PEMFC) operation has triggered varieties of advancements namely on the thermal management engineering scope. Nanofluids as an innovative heat transfer fluid solution are expected to be a promising candidate for alternative coolant in mini channel cooling plate of PEMFC. In this work, heat transfer performance of low concentration of 0.1, 0.3 and 0.5 % Al2O3 in water: Ethylene glycol (EG) mixtures of 100:0 and 50:50 nanofluids have been studied and compared against its base fluids at Re number ranging from 10 to 100. A steady, laminar and incompressible flow with constant heat flux is assumed in the channel of 140mm × 200mm. It was found that nanofluids have performed better than the base fluid but the demerit is on the pumping power due to the higher pressure drop across mini channel geometry as expected.

Thermal and electrical experimental characterization of Ethylene Glycol and water mixture nanofluids for a 400w Proton Exchange Membrane Fuel Cell

Nanofluid is an emerging technology in heat transfer study. The effect of nanofluids as a cooling medium in liquid cooled Proton Exchange Membrane Fuel Cell (PEMFC) is studied. Nanofluids with 0.1% and 0.5% volume concentration of Al2O3 are dispersed in base fluid of 50:50 mixture of Ethylene Glycol and water were analyzed experimentally. A rated power of 400 W liquid cooled PEMFC was used to verify the findings. The result showed that insignificant improvement in performance of PEMFC with nanofluids through polarization curve findings, perhaps due to the lower wattage of PEMFC used. The advantage of nanofluids utilization in PEMFC might be visible in higher wattage of PEMFC due to higher working fluid temperature. Higher thermal conductivity of nanofluid at higher temperature is expected to give advantage in terms of polarization curve of a PEMFC. However, the thermal performance is improved through the heat transfer rate increment of 68.5 % and 46 % for both 0.5 % of Al2O3 nanofluid and 0.1 % of Al2O3 nanofluid respectively.

Thermal Analysis of Heat Recovery Unit to Recover Exhaust Energy for Using in Organic Rankine Cycle

Heat engines convert only approximately 20% to 50% of the supplied energy into mechanical work whereas the remaining energy is lost as rejected heat. Although some of the energy lost is intrinsic to the nature of an engine and cannot be fully overcome (such as energy lost due to friction of moving parts), a large amount of energy can potentially be recovered. This paper presents a heat transfer analysis of a WHE for recovering wasted exhaust energy whilst transferring energy to different organic working fluid used in the OrganicRankine Cycle. The types of considered fluids are R-134a, Propane and Ammonia. The results show that the Ammonia has the highesteffectiveness of 0.25. The maximum heat transferrate of 48.5 kW was recovered using the Ammonia at the exhaust gas temperature of 700°C.