In order to reduce the consumption of fossil fuels and the emission of carbon dioxide, utilizing unused heat such as waste heat from factories and solar heat is important. In this study, heat transport amount and pressure drop of the latent/sensible heat transport medium which includes erythritol and surfactants were studied to improve the heat transport efficiency above 100°C required to use solar chemical heat pump etc. A pipeline was assembled and sample mixtures were run into it to measure the pressure drop and the temperature changes. The results showed that the heat exchange medium: silicone oil including 10 wt% erythritol with addition of surfactant: 5 wt% oleyl alcohol increased the transportable heat by the latent heat without significant pressure drop. The transportable energy calculated from this value was increased to about 3 times and expected to be applied as a heat exchange medium flowing at 100°C or over.

Frost formation on heat exchangers has been matter in years at refrigeration and air-conditioning domain, because it becomes a factor for decreasing heat exchange efficiency and increasing resistance of flow, and so defrosting is absolutely necessary. In this study, we proposed the microfabricated cooling surface for the mechanical defrosting as an alternate means of defrosting by heating. We investigated the effect of lattice shaped surface on the formation and growth of frost crystal by CFD simulation and observation of cooling surface. Then, we confirmed that the lattice shaped microfabricated surface was effective in suppressing frost formation and forming a fragile frost layer.

Although there are many papers of the mixing power consumption, there is no paper that quantitatively discusses an effect of surface roughness of impeller blades on power consumption. In this paper, authors experimentally verified the effect of surface roughness of mixing impeller on the power consumption by machining the surfaces of various impellers to mimic rust and material changes. As a result, the ratio of surface roughness and diameter of the impellers had no effect on the power consumption when ε/ d≤0.0125.