Abstract: This gas production system includes: a gas production device having a reactor forming a flow path for a treatment target gas, a first electrode and a second electrode to which voltage is applied, and a catalyst layer provided in the flow path and containing a catalyst; voltage generation means for generating voltage to be applied to the first electrode and the second electrode; and gas supply means for supplying the treatment target gas to the gas production device. The voltage generation means has frequency setting means for setting the frequency of the voltage in accordance with the treatment target gas, plasma generated between the first electrode and the second electrode is applied to the catalyst layer, and the treatment target gas is reformed to obtain a product gas.

Abstract: An air-conditioning apparatus includes a drain pan that receives water, and a detector including an ultrasonic sensor that emits and receives ultrasonic waves. The detector analyzes a response signal from the ultrasonic sensor to detect a contaminant generated in the drain pan. A bottom flat surface portion that forms a bottom of the drain pan is located parallel to a flat surface portion that forms a receiving surface of the ultrasonic sensor.

Abstract: A gas production system which applies plasma to a catalyst in a reactor and reforms a supplied source gas and a supplied oxidant gas to produce a product gas, includes: gas ratio change means for changing a ratio between the source gas to be supplied to the reactor by source gas supply means and the oxidant gas to be supplied to the reactor by oxidant gas supply means; and plasma generation means for generating the plasma to be applied to the catalyst. Thus, formation of highly reactive chemical species on a catalyst surface is efficiently promoted, whereby the yield of the product gas and energy efficiency are improved.

Abstract: This gas production system includes: a gas production device having a reactor forming a flow path for a treatment target gas, a first electrode and a second electrode to which voltage is applied, and a catalyst layer provided in the flow path and containing a catalyst; voltage generation means for generating voltage to be applied to the first electrode and the second electrode; and gas supply means for supplying the treatment target gas to the gas production device. The voltage generation means has frequency setting means for setting the frequency of the voltage in accordance with the treatment target gas, plasma generated between the first electrode and the second electrode is applied to the catalyst layer, and the treatment target gas is reformed to obtain a product gas.

Abstract: An air-conditioning apparatus includes a drain pan that receives water, and a detector including an ultrasonic sensor that emits and receives ultrasonic waves. The detector analyzes a response signal from the ultrasonic sensor to detect a contaminant generated in the drain pan. A bottom flat surface portion that forms a bottom of the drain pan is located parallel to a flat surface portion that forms a receiving surface of the ultrasonic sensor.

Abstract: An air-conditioning apparatus that conditions introduced air includes an ultraviolet sterilizer that emits ultraviolet ray to the air. The ultraviolet sterilizer includes a sterilizing light screen forming unit that forms a screen-shaped sterilizing light screen based on the emitted ultraviolet ray.

Abstract: An air-conditioning apparatus makes it possible to detect the presence or absence of a biofilm without the influence of water surface. The air-conditioning apparatus performs at least cooling operation or humidifying operation. The air-conditioning apparatus includes a drain pan to receive water, a draining unit to drain water received in the drain pan, and a detection unit to detect a biofilm formed in the drain pan. The detection unit performs the detection of the biofilm in a state in which draining of water from the drain pan is complete.

Abstract: An air-conditioning apparatus that conditions introduced air includes an ultraviolet sterilizer that emits ultraviolet ray to the air. The ultraviolet sterilizer includes a sterilizing light screen forming unit that forms a screen-shaped sterilizing light screen based on the emitted ultraviolet ray.

Abstract: A water heater, which allows efficient deposition of a scale component dissolved in water so as to reduce adhesion of the scale to a heat-transfer channel. The water heater includes: scale deposition device including a tank, an anode and a cathode provided in the tank so as to be opposed to each other, and a first power supply for applying a voltage between the anode and the cathode, the scale deposition device depositing a scale component dissolved in water retained in the tank; a heat-transfer channel provided at downstream of the scale deposition device, for guiding the water; and a heat source for heating the water by heat exchange in the heat-transfer channel, in which the scale deposition device includes oxygen-gas supplying/dissolving means for supplying an oxygen gas to a water feed pipe for feeding the water to the tank and dissolving the oxygen gas in the water.

Abstract: Provided is a water heater, which allows efficient deposition of a scale component dissolved in water so as to reduce adhesion of the scale to a heat-transfer channel. The water heater includes: scale deposition means including a tank, an anode and a cathode provided in the tank so as to be opposed to each other, and a first power supply for applying a voltage between the anode and the cathode, the scale deposition means depositing a scale component dissolved in water retained in the tank; a heat-transfer channel provided at downstream of the scale deposition means, for guiding the water; and a heat source for heating the water by heat exchange in the heat-transfer channel, in which the scale deposition means includes oxygen-gas supplying/dissolving means for supplying an oxygen gas to a water feed pipe for feeding the water to the tank and dissolving the oxygen gas in the water.

Abstract: The present invention is to realize supercooled freezing as a method of enhancing the quality of frozen food with a simple arrangement by a method other than quick freezing. Further, the present invention is to obtain a refrigerator and a frozen food preservation method capable of realizing high quality freezing by a simple arrangement. The refrigerator, which stores food making use of the cold air generated by a cooler 3, includes a supercooling case 81 for keeping the stored food in a supercooled state, in which the food is not frozen even at a temperature equal to or less than the freezing point of the food, for at least a predetermined period of time. The supercooling case 81 is composed of, for example, a lower case of two-stage type upper and lower cases disposed in a switching chamber 200 capable of being switched to a plurality of temperature zones.