In this paper, we covered the basic design process of water-cooled cabinets and studied how to determine the target performance of heat exchanger design, which is essential in water-cooled cabinet design. A theoretical method was presented to set the target efficiency of the heat exchanger, and the pressure drop of air passing through the heat exchanger was predicted analytically. A cabinet-level thermal analysis was performed using the target efficiency and pressure drop data of the heat exchanger. The accuracy of the theoretical method was judged by comparing the theoretically predicted operating environment of the internal equipment with the analytically predicted operating environment of the internal equipment.

Reducing underwater radiated noise from a ship is a critical issue for ensuring the survivability of the vessel. As high-speed signal processing and interlocking algorithms become more sophisticated, the heat intensity of shipboard equipment is increasing per unit volume. When designing shipboard equipment, it is necessary to consider the trade-off between heat dissipation and noise reduction. Following an analysis of the trade-offs, it was determined that the arrangement of Fan Ass'y A and B exhibited excellent noise and heat dissipation characteristics. Based on this, PWM control operating zones were derived. It was determined that the placement of Fan Ass'y A and B in the operating zone would increase the PWM duty cycle from 33% to 58% using a signal frequency of 25kHz band with guaranteed reliability. This would increase the noise by approximately 9dB(A) but reduce the internal board reference temperature by up to 15℃.

In this study, the cooling performance change according to the arrangement of the fin-tube heat exchanger using a single tube and the cooling performance change according to the air flow rate were studied. The arrangement of basic heat exchanger was set to 4 columns and 4 rows, and the performance change was studied while changing the columns and rows. In addition, the performance change was investigated by changing the air flow rate of the basic heat exchanger.

Electrochemical reductive extraction of tin from semiconductor plating process wastewater was experimented using synthetic wastewater. Copper and graphite plate were used as a cathode and an anode, respectively. The tin extraction could be optimized in pH 0.5 and polar space of 60 mm. The extraction rate of tin per minute was increased as current and initial tin concentration increased, and more than 87% and 97% of tin could be extracted within 80 minutes at 500 mg/L and 1,000 mg/L of initial tin concentration, respectively. The electrochemical reaction orders and kinetic coefficients were 1.24 ~ 1.26 and 0.004 ~ 0.006 (L/mg)(n − 1)min−1. The residual concentration of tin could be expressed as Ct= (Co −0.246+ 0.0012t)−4.065.

Food waste, food leachate and livestock wastes from an usual farm and a farm using much disinfectant were mixed to incubate within anaerobic serum bottle for BMP test. The methane yield rate and lag phase were determined by the modified Gompertz model and the Logistic model. The maximum methane yield rates by the modified Gompertz model were 15.9 ~ 41.0 mL CH4/g VS and higher than by the Logistic model. The modified Gompertz model was more appropriate than the Logistic model to have higher determination coefficient R2. The methane fermentation of mix with sole livestock waste from the farm using much disinfectant had ninefold lag phase and 40% or lower maximum yield rate comparing with the mix with sole usual livestock waste. The methane yield rate from a tonne of mix was increased as the ratio of food waste and food leachate increased. The cumulative methane yield was in the proportion of 40 m3 to a tonne of food wastes. The results of BMP test were analyzed by a response surface methodology (RSM) and modelized to a binomial expression, which was verified by analysis of variance (ANOVA) and to be appropriate for this case.

Economic and environmental aspects of electrochemical copper recovery from LCD manufacturing process and through hole plating process for PCB circuit board wastewater were evaluated. The extraction rate of copper per unit energy was decreased as HRT increased and initial copper concentration decreased. About 65 minutes was determined as the optimal HRTs which could maximize the productivity of copper recovery on energy. The extracted mass of copper from the wastewater were 0.045 g at 50 mg Cu/L, 0.083 g at 1,000 mg Cu/L and 0.098 g at 3,000 mg Cu/L by unit energy (Wh) for 60 minutes, respectively. LCA (Life Cycle Assessment) technique determined the electrochemical recovery of copper to have more effect on global warming than other environmental impact categories.

Electrochemical reductive extraction of copper from LCD manufacturing process and through hole plating process for PCB circuit board wastewater was experimented using synthetic wastewater. Copper plate which could be used as raw material through melting with extracted copper from wastewater and graphite plate were used as a cathode and an anode, respectively. The copper extraction could be optimized in pH 2 and polar space of 45mm. The extraction rate of copper per unit energy was decreased as HRT increased and initial copper concentration decreased. As the optimal HRTs which could maximize the productivity for copper on energy, 80 ~ 110 min at 50 mg/L, 64 min at 1,000 mg/L and 77 ~ 98 min at 3,000 mg/L were determined, respectively.