Development of a New Heat Source Based on Inducing Heat for Greenhouses

Abstract

In Fukuroi City Japan, greenhouses are usually used for crown musk melon (CMM) cultivation. When the temperature inside the greenhouse is lower than 25 °C, the CMM quality deteriorates. Hence, from late autumn until the middle of spring, oil is used to supply hot water to greenhouses from a boiler through a heat exchanger . However, since oil prices have recently soared, fuel expenses have drastically increased which heavily pressures the CMM business. In addition, with the promotion of the carbon-neutral policy, environmentally friendly heat sources are emphasized instead of fossil fuels. The TSK corporation has produced a new inducing heating (IH) source where heat is generated by rotating a plate on which a couple of permanent magnets are mounted using a motor. Since the rotation speed is easily controlled, the IH heat source capacity can be freely adjusted. To apply the IH source to the greenhouse, an experimental system was created in this study. During the experiment, water inside a vessel (maximum volume of 90 L) was heated to 70 °C by the IH system. Then, the heated water was circulated for heat dissipation through a heat exchanger by a pump. When the temperature of the water was lower than the target temperature, the IH system restarted to heat the water back up to 70 °C. Under several experimental conditions, the heating time, reheating time, and electric power were measured and evaluated. It was confirmed that the new IH heat source could possibly be applied to greenhouses.

Keywords

• greenhouse heat source
• IH
• carbon-neutral
• permanent magnet