• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.5
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• pp.263-269
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• 2017

A piezoelectric cantilever energy harvester (PCEH) driven in longitudinal (3-3) vibration mode was fabricated, and its electrical properties were evaluated by varying the resistive load. A commercial PZT piezoelectric ceramic with a high piezoelectric charge constant ($d_{33}$) of 520 pC/N and the interdigitated (IDT) electrode pattern was used to fabricate the PCEH driven in longitudinal vibration. The IDT Ag electrode embedded piezoelectric laminates were co-fired at $850^{\circ}C$ for 2 h. The 3-3 mode PCEH was successfully fabricated by attaching the piezoelectric laminates to a SUS304 elastic substrate. The PCEH exhibited a high output power of 3.8 mW across the resistive load of $100k{\Omega}$ at 100 Hz and 1.5 G. This corresponds to a power density of $10.3mW/cm^3$ and a normalized global power factor of $4.56mW/g^2{\cdot}cm^3$. Given the other PCEH driven in transverse (3-1) vibration mode, the 3-3 mode PCEH could be better for vibration energy harvesting applications.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.163-169
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• 2019

This study is a research to compare efficiency of new cooling system (chiller, pre-cooler) to that of the conventional system at the hydrogen refueling station (HRS). This study includes contents for thermodynamic comparison of cooling system for HRS and comparison of pros and cons of its components. So It is to establish design concept of cooling system of HRS supplying with fuel cell electric vehicle (FCEV). HRS is charging high pressure H2 (700 bar) to FCEV. However cooling system is need to prevent temperature rise in tank. This cooling system consists of pre-cooler and chiller system.