풍력 에너지 이용을 위한 유압식 열변환장치에 관한 연구

Abstract

This study suggests a new energy conversion system which converts wind energy, one kind of natural energy, to heat energy with high efficiency in standpoints of energy economics and equipment manufacturing cost. Presently, electric power generation with wind energy is popular method of using wind energy. Actually, however, it is not so much of practical use. The reason for this is such that the quality of the electric power is poor because of fluctuation in voltage, frequency and output, and then most of the electric power is used for heating water. Also, such electric energy usage for heating water generally agrees with the energy requirements because wind power plants are usually located in cold districts. But studies for direct energy conversion from wind energy to heat energy are very rare. Accordingly, a new energy conversion system which converts wind energy directly to heat instead of transforming it to electric power beforehand is suggested in this study. The new energy conversion system is composed of two big parts divided by their function. One of it is a wind turbine part, and another is the heat energy conversion part. The object of this study is confined only to the heat energy conversion part. The usefulness of the new energy conversion system was confirmed by experiments using an experimental energy conversion system with 3.75[KW] power capacity. The experimental system is composed of one closed oil circulation circuit and one closed water circulation circuit. Heat generated in the oil circuit is transferred to the water circuit through a heat exchanger and stored as state of sensible heat of water in a tank. By the way, focus is this study is on the heat energy conversion part, so the wind turbine is replaced with an electric motor for the convenience of experiment. In the experimental process, pressure difference at the hydraulic pump, revolution speed of the hydraulic pump, temperature at a few points on the oil circuit and the water circuit are measured at internals of five minutes. And integral values of input energy to the system and stored energy in the system is computed. The representative results obtained in this study are summarized as follows. 1. The energy conversion efficiency is very high. 2. Reliability and durability are excellent, maintenance is easy and low cost manufacturing is possible. 3. Energy storage is easy.