Provided is an air conditioning apparatus. The air conditioning apparatus includes an outdoor unit through which a refrigerant is circulated, an indoor unit through which water is circulated, and a heat exchange device including a heat exchanger in which the refrigerant and the water are heat-exchanged with each other. The heat exchanger includes a high-pressure guide tube, a low-pressure guide tube, a liquid guide tube, a bypass tube configured to connect a bypass branch point of the high-pressure gas tube of the outdoor unit to a bypass combination point of the liquid guide tube to bypass a high-pressure refrigerant existing in the high-pressure tube to the liquid guide tube, and a bypass valve installed in the bypass tube. The outdoor unit includes a first valve device configured to guide a refrigerant compressed in the compressor to the outdoor heat exchanger and a second valve device configured to guide the refrigerant compressed in the compressor to the high-pressure guide tube of the heat exchange device.

An HVAC system includes a reversing valve configured to receive refrigerant and direct the received refrigerant based on an operating mode of the HVAC system. The HVAC system includes first and second sensors. A sensor measures a heat-exchanger temperature associated with the outdoor heat exchanger. A controller monitors an outdoor temperature and the heat-exchanger temperature and compares these temperatures. The controller determines whether the HVAC system is intended to operate in a cooling or heating mode. If the heat-exchanger temperature is less than the outdoor temperature and the HVAC system is intended to operate in the cooling mode, the controller determines that a first reversing-valve fault is detected. The first reversing-valve fault is associated with the reversing valve being in the heating configuration when the HVAC system is intended to operate in the cooling mode.

An HVAC system includes a reversing valve configured to receive compressed refrigerant and direct the refrigerant based on an operating mode of the HVAC system. One or more suction-side sensors measure suction-side properties associated with refrigerant provided to an inlet of the compressor. The suction-side properties comprise a suction-side temperature. One or more liquid-side sensors measure liquid-side properties associated with the refrigerant provided from an outlet of the compressor. A controller monitors the suction-side property and liquid-side property. The controller determines whether the suction-side property is greater than the liquid-side property. If the suction-side temperature is greater than the liquid-side temperature, the reversing valve is determined to be in an equalizing configuration. The equalizing configuration corresponds to a configuration in which the refrigerant provided from the outlet of the compressor is directed to the inlet of the compressor without first being directed to other components of the HVAC system.

Modular heating and cooling systems may include one or more modules connected to a fluid input and fluid output. Conventional modular heating and cooling systems typically use a single fluid in the cooling, heating and source fluid loops due to the mixing of fluids in the system. According to an aspect there is provided a modular heating system comprising at least one heating and cooling apparatus. The apparatus comprises a first heat exchanger, a second heat exchanger and a third heat exchanger. The apparatus further comprises a refrigerant line system coupled to the first (e.g. cooling), second (e.g. heating) and third (e.g. source) heat exchangers and configurable for selectively directing refrigerant fluid through the heat exchanger to provide multiple modes of operation. The heating, cooling and source fluid loops may be separate and independent such that the fluids do not mix.

Various embodiments of a heat pump system are disclosed to provide improved and flexible heat pump operation when dehumidification of the conditioned space is required. In one embodiment, a heat pump system includes a heat pump loop comprising a refrigerant circuit that fluidly interconnects (1) a compressor; (2) a source heat exchanger; (3) a source heat exchanger bypass circuit comprising a bypass valve; (4) a space heat exchanger; (5) a reversing valve positioned on the discharge side of the compressor; (6) a reheat circuit comprising a reheat heat exchanger; (7) first and second expansion devices; and (8) first and second expansion device bypass circuits configured to allow refrigerant to bypass the first and second expansion devices, respectively, where the first and second bypass circuits include first and second check valves, respectively; and (9) a 3-way valve configured to selectively direct refrigerant flow to the first expansion device, the reheat circuit, and the second expansion device.

The present disclosure relates to a heat exchanger and an air conditioner improving heat exchange ability by optimizing the number of high protrusions of a heat transfer tube and a height difference between the high protrusion and a low protrusion to increase the heat transfer performance of the heat transfer tube or reduce the pressure loss in the tube. An air conditioner includes the heat exchanger including a heat transfer tube configured to allow the refrigerant to flow, fins installed on the heat transfer tube, and fin collars forming an insertion hole through which the heat transfer tube is inserted and passes, and the fin collars is in contact with the heat transfer tube by tube expansion of the heat transfer tube. The heat transfer tube includes high protrusions disposed in a spiral shape with respect to a tube axis direction of the heat transfer tube, twenty one to twenty seven of the high protrusions being formed along a circumferential direction of the heat transfer tube, and low protrusions disposed between two of the adjacent high protrusions along the circumferential direction of the heat transfer tube and having a height lower by 0.03 mm to 0.05 mm than the high protrusions.

Aspects of the invention are directed towards a system and method for varying the refrigerant flow using a flow diverter of a reversing valve in heat pumps. One or more embodiments of the invention describe the method comprising steps of receiving, by a control circuit, a command for operating a reversing valve in a plurality of modes. The reversing valve comprises a first tube, a second tube, a third tube and a fourth tube. The method comprising steps of determining a tonnage profile for refrigerant to flow in the reversing valve, generating a signal based on the command and the tonnage profile and communicating the signal to a stepper motor. The method further comprising steps of rotating a flow diverter of the reversing valve by the stepper motor based on the signal. The rotation of the flow diverter allows the refrigerant to flow in one of the plurality of modes.

Provided are a control method of a heat pump system and a heat pump system. The heat pump system includes a throttling element and a four-way valve. The four-way valve has a first state in a case that the heat pump system operates for refrigerating and a second state in a case that the heat pump system operates for heating. The control method includes that: before the four-way valve is switched from the first state to the second state, A is compared with B, and switching of the state of the four-way valve is controlled and the opening degree of the throttling element is adjusted according to the comparison result, or switching of the state of the four-way valve is controlled according to the comparison result, or the opening degree of the throttling element is adjusted according to the comparison result.

A system and method for positioning a slider of a reversing valve. A method includes receiving a command for operating a reversing valve in a first mode, a second mode or a third mode. The reversing valve comprises a first tube, a second tube, a third tube, and a fourth tube. The method further describes determining a tonnage profile for refrigerant to flow in the reversing valve. The method further describes communicating the command and the tonnage profile to a stepper motor and linearly moving a lead screw based on the command and the tonnage profile to position a slider on the second tube and the third tube in the second mode and the third mode or on the third tube and the fourth tube in the first mode.

The refrigeration cycle apparatus includes a refrigerant circuit, a controller to control the refrigerant circuit, a bypass flow path, and a flow control valve. The bypass flow path communicates between the discharge side of the compressor and the first outdoor heat exchanger or between the discharge side of the compressor and the second outdoor heat exchanger. The flow control valve is provided to the bypass flow path. The refrigerant circuit is configured to be able to perform a heating defrosting simultaneous operation. The heating defrosting simultaneous operation is an operation of supplying part of the refrigerant discharged from the compressor to one of the first outdoor heat exchanger and the second outdoor heat exchanger via the bypass flow path, causing the other of the first outdoor heat exchanger and the second outdoor heat exchanger to serve as an evaporator, and causing the indoor heat exchanger to serve as a condenser.