Speaker
Description
As the hydrogen mobility market has grown in recent years, liquid hydrogen fueling stations, which are capable of delivering higher amounts of hydrogen than gaseous hydrogen fueling stations, have attracted increasing attention. Liquid hydrogen fueling stations include evaporation systems that convert liquid hydrogen into gas and heat it up to the right temperature. For normal operation, the evaporation systems must be able to convert liquid hydrogen into gas at a rate of at least 100kg/hr. Whether they can meet these requirements or not depends on the performance of the heat exchanger, which is a core equipment of the evaporation systems. The problem is that heat exchangers used in hydrogen fueling stations are very large compared to ordinary heat exchangers due to the high pressure and cryogenic environment in which they operate. As the increase of the heat exchanger size leads to the increase of the system size and reduces the economic feasibility, a key issue in the development of liquid hydrogen fueling stations is to minimize the size of the heat exchangers by maximizing their effectiveness. In this study, it is investigated whether Printed Circuit Heat Exchangers (PCHEs), which are known to have high effectiveness, can be applied to liquid hydrogen fueling stations. To this end, lab-scale PCHEs are designed and fabricated, and their performance is evaluated by using an experimental facility capable of creating a cryogenic environment. Due to regulatory restrictions, liquid nitrogen is used to conduct the experiment instead of liquid hydrogen, and 50% ethylene glycol water mixture is used as a working fluid for the hot side. The PCHE material is SUS 316L, and the number of plates is two each for the cold and hot sides. For the parametric study, four PCHEs are fabricated using a combination of cold side plates with channel diameters of 1mm and 2mm, and hot side plates with channel diameters of 2mm and 3mm. Their performance is evaluated by measuring the flow rate, temperature and pressure at the inlet and outlet sides of the PCHEs. It is found that the effectiveness of the PCHEs is ranged from 0.75 to 0.99 depending on the flow rate and the channel diameter. The effectiveness increases as the flow rate increases and the cold side channel diameter decreases. The hot side channel diameter does not have a significant effect on the effectiveness of the PCHEs. The results of the experiments confirm that the effectiveness of PCHEs can be close to 1 in cryogenic environments if the flow rate and channel diameter are properly designed.
| Submitters Country | South Korea |
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