Karasumi is salted-dried mullet Mugil cephalus roe. Similar products are produced all over the world. To clarify a reason why lipids in karasumi are very stable compared with those in other dried seafood products, the effects of wax ester (WE) in mullet roe lipids on the lipid oxidation were investigated in the present study. Peroxide value and thiobarbituric acid reactive substances of total lipids were significantly lower than those of total lipids without WE during the storage period. In addition, fatty acid composition (ratio) of the lipids without WE exhibited increase of saturated fatty acids and decrease of n-3 series poly unsaturated fatty acids. 2, 2-diphenyl-1-pikryl-hydrazylradical scavenging activity of WE extracted from the mullet roe lipids was extremely low. These results suggest that WE in mullet roe prevents the lipid oxidation of Karasumi by physical blockage from outside air.

The objective of this study is to develop a desiccant system using Wakkanai Siliceous Shale (WSS). This article is the 8th report of the series. The regeneration temperature of a two-rotor system reached up to 55 ^oC or higher. Consequently, we planned a new system layout to reduce the regeneration temperature. This system consists of a total heat exchange element (T-HEX), a heating coil, a precooling coil and one WSS desiccant rotor. Firstly, performance prediction was conducted to decide the specification of the HEX by numerical calculation. Regeneration temperature is capable of being decreased by an increase of the total heat exchange efficiency. Secondly, an experiment was conducted to verify the calculation result. As a result, to achieve high exchange efficiency (ηS=0.88, ηL=0.8), the air velocity in the element is preferably regulated to 0.9-1.1 m/sec. In addition, the optimal rotation speed of the desiccant rotor was calculated. As a result, the optimal rotation speed was 10 rph to perform the high adsorption amount. Finally, we evaluate the optimal control conditions of new system by the numerical calculation. As a result, it is clear that the new system is capable to remove the latent heat load at a low regeneration temperature of 30-55 °C, and these values are lower than those in the two-rotor system. Furthermore, this system reduces the regeneration and precooling energy by up to 50 %.

This study presents a new idea for an empirical method to calculate the bypass leakage mass flow rate along the tip seal in scroll compressors. A bypass leakage test model was precisely developed to be compatible with a practical scroll compressor with large cooling capacity. Detailed tests of pressure decay in a pressurized vessel due to the bypass leakages were conducted with dry refrigerant gas R410A. The measured pressure decay characteristics were subsequently simulated using the Darcy-Weisbach equation with an empirical friction factor determined in our previous study for the leakage flow through axial clearances. In the present simulations of the measured pressure decay, the complicated flow patterns through bypass clearances were decomposed into two thin representative rectangular cross-section leakage passes, one with the effective mean width and another with the effective mean length. Empirical values of the effective pass width and length were determined so that the measured pressure decays are well predicted by the calculations. As a result, the bypass leakage flow rate along the tip seal in scroll compressors can be calculated by a very simple scheme introducing the parallel leakage passes with a thin rectangular cross-section.

Optimum utilization of heat by thermal storage is one of the solutions to improve efficiency and to save energy for various heat pump systems. Beverage vending machine controls the temperature of the beverages by thermal energy exchanged with the refrigerant of the compression type heat pump. Further improvement of the heating-energy is demanded, because it accounts for as much as 60% of the total power consumption. In this research, in order to save power of the beverage vending machines with CO₂ heat pump, we clarified some design guidelines of two types of a latent heat thermal storage tank. 1st thermal storage tank used for a heating room has two heat transfer surfaces; it stores CO₂ heat during the heat pump running, and then releases it into the heating room during the heat pump stopping. For 1st thermal storage tank, it is found that thermal conductivity enhancement in the thermal storage side is effective, and that heat transfer enhancement into the air side is necessary. 2nd thermal storage tank used for heating and evaporating the CO₂ before compression has only one heat transfer surface; it stores heat of CO₂ flowing after the heating room, and then releases it into CO₂ for evaporation before compressor. For 2nd thermal storage, we showed some contribution of each parameter in thermal storage tank.

The objective of this study is to develop a desiccant system using Wakkanai Siliceous Shale (WSS). This article is the 9th report of the series. This system consists of a total heat exchange element (T-HEX), a heating coil, a precooling coil and one WSS desiccant rotor. Although this system is possible to regenerate at low temperature, the supply air (SA) temperature rise due to rotation is still confirmed. Consequently, due to the introduction of the purge zone was planned to reduce the SA temperature. The route of this purge system branches part of return air and purge air supplies directly to the rotor. Firstly, the performance evaluation of the case with different airflow balance between outside air and return air was performed for the total heat exchange element. As a result, the upper limit of purge air flow was up to 20 %(30 m³/h) of ventilation rate. Secondly, the experiment was carried out to confirm the dehumidification amount and SA temperature by the purge. It is cleared that the dehumidification amount was slightly increased by the purge air.Also, it is clear that the SA temperature decrease is shown in Fig.A-1. In addition, numerical calculation was conducted to optimize the rotation speed and the purge air flow rate. The calculation results are shown in Figs,A-2(a) and (b). As a result, the case of the low rotation speed of 10rph showed the highest dehumidification amount, and SA temperature capable to reduce by1.2-3.4 ° C. Finally, the optimum purge air flow rate was 30 to 18 m³/h at the regeneration temperature of 40 to 60 ° C.

In selecting a refrigerant, it is necessary to consider not only ODP and GWP but also the impact on global warming from various aspects. It is therefore indispensable to continue to search for better refrigerants that minimize impact on the climate to the total CO2 equivalent. Recently, a new refrigerant R 452B was reported as a high-efficiency refrigerant. There is a possibility that excellent performance may be exhibited depending on the use load of the air conditioner. We carried out cooling performance comparison in wide capacity range for R 452B and R 32. As a result, it was found that the performance difference becomes large in high ambient temperature and high heat load. We also analyzed the causes.

Interest in the roomtemperature magnetic refrigerator, which is an environmentally friendly refrigeration system, is increasing. Previous studies have revealed that the maximum temperature span of the magnetic refrigerator is expanded by layered beds of multiple materials with different curie temperatures in AMR(Active Magnetic Regenerator). But, the effective factors of the layered beds configuration of multiple materials are not revealed. In this study, we investigated with onedimensional heat transfer numerical analysis the performance of layered beds of manganese(Mn)based compounds which has a larger magnetic entropy change than conventional gadolinium(Gd)based compounds. Analysis results show that when the AMR duct length and the curie temperature of the cold end and hot end materials are fixed, the achieved temperature span of multilayered beds is not affected by the curie temperature interval, while its cooling power is increased with the decreasing of the curie temperature interval. In the layered beds of multiple materials with the preferable curie temperature interval, the achieved cooling power is determined by the cold side materials, on the other hand the temperature span is expanded by the other materials.