Abstract: Disclosed are a heat pump boiler and a control method for the same. The heat pump boiler includes an outdoor unit having an outdoor-unit heat-exchanger, a water pipe including a water-feed pipe and a water-return pipe connected to the outdoor unit to feed water to the outdoor unit or to return low-temperature or medium-temperature water produced in the outdoor unit to an external location, heat exchangers connected to the water pipe to produce medium-temperature or high-temperature water, a variable-capacity compressor connected to the heat exchangers, a buffer tank connected to the water pipe, and an externally-wound heat exchanger to collect waste heat radiated from the compressor. A temperature of water stored in the buffer tank is raised using the collected waste heat, and, during a defrosting operation, the water stored in the buffer tank is fed to the outdoor-unit heat-exchanger to defrost an evaporator of the outdoor unit.

Abstract: A refrigerant cycle device capable of preventing inflow of a liquid refrigerant into a compressor and having a compact structure is disclosed. The refrigerant cycle device includes a compressor, a gas cooler, a pressure reducing device, an evaporator, and a heat exchanger to heat-exchange a refrigerant discharged from the gas cooler and a refrigerant discharged from the evaporator. The heat exchanger includes a first passage connected to an outlet of the gas cooler and a second passage connected to an outlet of the evaporator. The refrigerant in the first passage flows downward, and the refrigerant in the second passage flows upward.

Abstract: A refrigerant cycle device capable of preventing inflow of a liquid refrigerant into a compressor and having a compact structure is disclosed. The refrigerant cycle device includes a compressor, a gas cooler, a pressure reducing device, an evaporator, and a heat exchanger to heat-exchange a refrigerant discharged from the gas cooler and a refrigerant discharged from the evaporator. The heat exchanger includes a first passage connected to an outlet of the gas cooler and a second passage connected to an outlet of the evaporator. The refrigerant in the first passage flows downward, and the refrigerant in the second passage flows upward.

Abstract: A multi-stage rotary compressor to reduce a driving load and prevent a malfunction due to an abrupt pressure rising. In the compressor of the type including first and second compressing units mounted in a hermetic casing thereof to compress a gas, the gas being primarily compressed in the first compressing unit and secondarily compressed in the second compressing unit, the interior of the hermetic casing is divided into a plurality of spaces including first and second pressure chambers. The first pressure chamber surrounds the first compressing unit and is kept at a discharge pressure of the first compressing unit, and the second pressure chamber surrounds the second compressing unit and is kept at a discharge pressure of the second compressing unit.