Abstract: A flash water heater using a heat pump includes a heat exchanger in which a refrigerant flow path exchanges heat with a water flow path. Tap water is led directly to the water flow path, and hot water supplied from the water flow path is used. The water heater includes at least one of the following elements: 1) a load setter for setting a heating amount in the heat exchanger, and a heating controller for regulating a heating amount in response to an amount set by the load setter; 2) a heater for heating water flowing through the water flow path in the heat exchanger and water flowing the path before and after the heat exchanger; 3) plural compressors; and 4) plural heat-pump cycles. The water heater is excellent in start-up of hot water temperature when the hot water supply starts, controllability, and efficiency.

Abstract: A flash water heater using a heat pump includes a heat exchanger in which a refrigerant flow path exchanges heat with a water flow path. Tap water is led directly to the water flow path, and hot water supplied from the water flow path is used. The water heater includes at least one of the following elements: 1) a load setter for setting a heating amount in the heat exchanger, and a heating controller for regulating a heating amount in response to an amount set by the load setter; 2) a heater for heating water flowing through the water flow path in the heat exchanger and water flowing the path before and after the heat exchanger; 3) plural compressors; and 4) plural heat-pump cycles. The water heater is excellent in start-up of hot water temperature when the hot water supply starts, controllability, and efficiency.

Abstract: A heat transfer apparatus is provided with a refrigerant heater, a single container disposed above the refrigerant heater, and the radiator spaced from the container. The container accommodates a partitioning plate for separating the inside of the container into a gas-liquid separating chamber and a liquid-receiving chamber, and a valve body for selectively opening and closing an opening defined in the partitioning plate is disposed within the container. The valve body is driven by an electrically operated driver mounted on the container. The heat transfer apparatus is also provided with a first group of pipes for communicating the refrigerant heater and the gas-liquid separating chamber, and with a second group of pipes for communicating the gas-liquid separating chamber, the radiator, and the liquid-receiving chamber.