Ohara Junichi

In this study, focused on the waste heat energy from seafood processing plant as research to promote the use of unutilized energy. The waste heat energy from seafood processing plant contains large amounts of the high temperature waste gas from the production of fish cake, and the high temperature wastewater from the production of boiled whitebaits and bonito flakes. If these unutilized waste gases and wastewater could be recovered and utilized as the high heat sources, it would lead to significant energy savings. It is assumed that seawater will be used as the low heat source. Seafood processing plants are usually located close to the sea for processing fisheries caught in the sea, and we recommend the use of seawater as the cooling heat source. Therefore, it is necessary to design systems in consideration of the effects on the ocean environment in the area where seawater is discharged, which may lead to significant modification of the ocean environment. If the optimum flow rate of low heat source at maximum net power is identified, the pump power for seawater can be reduced and the flow rate of seawater into the heat exchanger can be minimized as needed, which is expected to reduce the amount of seawater contamination and lead to lower maintenance costs for the heat exchanger. As a result of this study, it was found that the optimum flow rate of low heat source exists for maximum net power and maximum turbine output. The maximum net power was higher when the temperature difference between inlet and outlet of low heat source was higher, while the maximum turbine output was higher when the temperature difference between inlet and outlet of low heat source was lower.

Learners of thermodynamics learn a basic thermodynamic state quantity “entropy” which is challenging to understand owing to multiple reasons. First, entropy is explained using multiple defining equations； intuitively understanding the meaning from the equations can be difficult. Second, entropy is often explained in terms of “clutter” and “disorder” of energy； however, the correspondence between these concepts and the defining equation is not obtained intuitively. Therefore, in this study, we considered a virtual lattice space in which gas molecules are arranged and developed a model that enables intuitive understanding and quantitative calculations using defining equations. Specifically, the model was implemented in spreadsheet software with 100 gas molecules in a virtual space of 100 lattices. The model showed that even such a simple model can define thermodynamic quantities and quantify the number of cases Win Boltzmann’s equation from the viewpoint of the arrangement of molecules in lattice space. This is a tool that can calculate and quantitatively examine all entropy from multiple entropy-defining equations. This calculation sheet shows that the calculated values of entropy by the Sackur–Tetrode equation and Boltzmann’s equation are almost the same. Furthermore, the entropy difference calculated using the thermodynamic defining equation dS = dQ/T was also consistent with the values by other equations. Therefore, the model can specifically calculate the values of various entropy-defining equations.

In this research, aiming at efficient cooling of the locally concentrated heating part of the electronic element, a new concentric circular microchannel plate that can efficiently cool the CPU is designed in consideration of the heat generation characteristics of the CPU. Then, we conducted an experiment on heat transfer when water was used as the refrigerant for this new microchannel plate, and grasped the basic heat transfer characteristics. Furthermore, by comparing the results with the straight microchannel plate having a simple structure, the heat transfer promotion of the concentric microchannel plate was examined. By using a concentric microchannel plate, the temperature at the center of the heater can be maintained at about 25℃, and even when compared with a straight microchannel plate, the temperature rise can be suppressed by about 8 to 23℃. The heat transfer coefficient of the concentric circular microchannel plate is 6 to 8 kW/m^2 K, which is almost constant, and about four times higher than the heat transfer coefficient of the straight microchannel plate at the same heat quantity and the same flow rate. In addition, the research results were compared with the previously proposed experimental correlation equation for single phase forced convection laminar heat transfer of straight microchannnels.