In this study, heat exchangers used in data center and building air-conditioners were tested according to the type of heat exchangers to select them for commercial use. The experiment was performed three samples, one micro channel heat exchanger, the same volume oval coil and the same performance oval coil. The experiment conducted under actual operation conditions in the data center and building. Micro-channel heat exchanger has lower air side pressure drop and higher capacity per volume than oval coil. It may be advantageous when the installation small space or the little design static pressure in the fan, such as in-row systems or CRAC installed in data center.

The heating & cooling performance of vapor compression heat pump using seawater heat source has been investigated experimentally for fish farm heat supply system. The principal parts of the heat pump systems are compressor, condenser, expansion devices and evaporator. The evaporator and condenser are both heat transfer devices. We used double pipe H/E(CASE-1) and shell&coil H/E(CASE-2) as evaporator, condenser of heat pumps. The experimental results were higher Uvalue 25% of double pipe heat exchanger compared to shell & coil H/E. The COPc is 4.74 and the COPH is 6.18 of the heat pump with shell & coil H/E.

Recently, ice-on-coil type ice storage system has become a very popular issue in application to electric powered air conditioning systems. An experimental study has been carried out to investigate the ice making characteristics of an ice-on-coil type ice storage system. The ice storage system used two rectangular tank, one is 900 ℓ with a thermal capacity 3,300 kcal/h and the other is 3,000 ℓ with a thermal capacity 9,900 kcal/h. An experimental data has been measured as the variation of a ice making time. The results indicate that the ice making rate increase due to variation of ice making time gradually, and is high in case of the smaller refrigerant coil from 5 hour but larger refrigerant coil after this.

An underwater speaker was made of a moving coil driver unite of usual speaker, acryl-boards, polyester resin, rubber and castor oil and it's frequency characteristics was measured in range of 250~600Hz in air water tank and sea. The results of measurements are follows: 1. Transmitting and receiving frequency of measurement frequency were similar in air, water tank and sea. 2. The input and output wave forms of a manufactured speaker which is not water-proof in air were similar to each other in 300~450Hz, but other frequencies showed distorted wave forms. 3. The input and output wave forms of an underwater speaker in water thank and sea were similar to each other in 250~600Hz. But output wave forms showed combination waves with very low frequency. 4. Transmitting and receiving frequency wave forms and resisting pressure of an underwater speaker at 80m in the depth of water were in good condition. Therefore it can be possible to use it as an underwater speaker.