Abstract: A plurality of heat transfer fins are arranged so as to surround straight pipe portions of heat transfer tubes connected through bends in a serpentine arrangement. Heat transfer surfaces for transferring heat between air of the heat transfer tubes and the heat transfer fins have holes each having a radius smaller than the critical radius of a nucleus that occurs upon phase change from water vapor to condensed water droplets such that the holes are filled with the air at all times. Water is allowed to move from the holes filled with the air having low surface energy to metal part having high surface energy, thus improving drainage.

Abstract: A refrigerant circuit of a heat pump water heater has a compressor, a four-way valve, a water heat exchanger, a heat storage transfer pipe contained in a heat storage water tank, an expansion valve, and an air heat exchanger and forms a refrigerating cycle by sequentially connecting them. A water circuit of the heat pump water heater has a water inlet pipeline that supplies water to the water heat exchanger, a hot water tank, and a water outlet pipeline that allows the water heat exchanger to communicate with the hot water tank, in which water is supplied to the heat storage water tank through a heat storage water tank water feed pipe branching from the water inlet pipeline by opening a heat storage water tank water feed opening/closing valve) and the water in the heat storage water tank can be discharged through the heat storage water tank water discharge pipe (by opening a heat storage water tank water discharge opening/closing valve).

Abstract: A refrigeration cycle apparatus includes a compressor, a condenser such as an indoor heat exchanger, first expansion means, and an evaporator such as an outdoor heat exchanger that are connected by refrigerant pipes to form a refrigeration cycle. The evaporator is a heat exchanger including a plurality of plate-like heat transfer fins arranged in parallel and subjected to water slip or water repellent treatment, and a heat transfer tube provided in contact with the plurality of heat transfer fins such that refrigerant flows therein. The refrigeration cycle apparatus further includes a drain pan disposed below the evaporator, an evaporator fan for producing an air current flowing to the evaporator, such as an outdoor fan, and a heating unit disposed at a position below the heat transfer fins and on a leeward side of the heat transfer fins.

Abstract: A plurality of heat transfer fins are arranged so as to surround straight pipe portions of heat transfer tubes connected through bends in a serpentine arrangement. Heat transfer surfaces for transferring heat between air of the heat transfer tubes and the heat transfer fins have holes each having a radius smaller than the critical radius of a nucleus that occurs upon phase change from water vapor to condensed water droplets such that the holes are filled with the air at all times. Water is allowed to move from the holes filled with the air having low surface energy to metal part having high surface energy, thus improving drainage.

Abstract: A refrigerant circuit of a heat pump water heater has a compressor, a four-way valve, a water heat exchanger, a heat storage transfer pipe contained in a heat storage water tank, an expansion valve, and an air heat exchanger and forms a refrigerating cycle by sequentially connecting them. A water circuit of the heat pump water heater has a water inlet pipeline that supplies water to the water heat exchanger, a hot water tank, and a water outlet pipeline that allows the water heat exchanger to communicate with the hot water tank, in which water is supplied to the heat storage water tank through a heat storage water tank water feed pipe branching from the water inlet pipeline by opening a heat storage water tank water feed opening/closing valve) and the water in the heat storage water tank can be discharged through the heat storage water tank water discharge pipe (by opening a heat storage water tank water discharge opening/closing valve).

Abstract: A sound source device is connected to one end of a pipe arrangement to supply sound into the pipe arrangement. Regenerators are installed to the pipe arrangement. Each regenerator serves as an energy converter that converts energy of an acoustic wave of the sound, which is propagated in the pipe arrangement, into another form of energy. Acoustic wave amplifier/attenuator apparatuses are provided in the pipe arrangement at a corresponding location between the sound source device and a corresponding one of the regenerators. Each acoustic wave amplifier/attenuator apparatus uses thermoacoustic effect to amplify or attenuate the acoustic wave and includes a cold heat exchanger, a hot heat exchanger and a stack that is held between the cold heat exchanger and the hot heat exchanger.