A design method of a step-type ultrasonic horn with non-uniform temperature distribution was studied with the aim to apply ultrasonic technologies to high temperature engineering applications. First, an alloy casting system with ultrasonic transmission using the horn was modeled by a theoretical link between heat transfer and sound propagation. Next, the design optimization method of the horn with non-uniform temperature distribution was presented. Based on the method, the characteristic lengths of the step-type horn, x₁ (axial length of small-diameter part), x₂ (axial length of large-diameter part), were calculated by varying design conditions: properties of material, temperature difference, and frequency. Defined by an odd multiple of one-quarter cycle of ultrasonic wave, the value x₁ increased stepwisely with the temperature rise of a specimen. On the other hand, the value x₂ decreased slightly with the temperature rise. Both the lengths x₁ and x₂ were decreased with increasing frequency. It was demonstrated that a machinable ceramic horn can be made compact in the design compared to a duralumin horn.

The ceiling-mounted type air conditioner is widely distributed in the market for stores and offices. There are several types, square shape with four blowing outlets per side is very popular type. Generally called "four-way ceiling cassette type" and this product occupies about 60% of the Japanese market. Air flow direction is bent 180 degrees in this product casing. This air flow management can be improved by reducing the bending angle. Research and develop new forms of air conditioners aimed at improving the air flow management. We achieved the effect of reducing motor input by half and noise by 5 dB with the same air flow. The air speed characteristics of the heat exchanger have also been improved, so energy savings can be expected for air conditioning system.