A system includes a pressure exchanger (PX). The PX is coupled to a motor that controls an operating speed of the PX. The system further includes a first pressure gauge configured to generate first pressure data indicative of a pressure of a fluid of a condenser. A first controller is to generate a first control signal based on the first pressure data. The motor of the PX is configured to adjust the operating speed of the PX based on the first control signal. The system further includes a pump. The system further includes a fluid density sensor for generating fluid density data associated with a first output fluid of the PX. A second controller is to generate a second control signal based on at least the fluid density data. The pump is to adjust an operating speed of the pump based on the second control signal.

A system includes a pressure exchanger (PX). The PX is coupled to a motor that controls an operating speed of the PX. The system further includes a first pressure gauge configured to generate first pressure data indicative of a pressure of a fluid of a condenser. A first controller is to generate a first control signal based on the first pressure data. The motor of the PX is configured to adjust the operating speed of the PX based on the first control signal. The system further includes a pump. The system further includes a fluid density sensor for generating fluid density data associated with a first output fluid of the PX. A second controller is to generate a second control signal based on at least the fluid density data. The pump is to adjust an operating speed of the pump based on the second control signal.

An EXV (electronic expansion valve) control system includes an EXV controller for controlling an EXV within the refrigerant loop of an HVAC system. The EXV controller implements a master control algorithm that includes a plurality of sub-control algorithms and an initial series of branching decision points to determine the current mode of operation and to execute select sub-control algorithms corresponding to the current mode of operation, while not executing the sub-control algorithms corresponding to the other modes of operation. The sub-control algorithms implement various combinations of PID (Proportional Integral Derivative) control and feed-forward control, the results of which can be mapped to specific control instructions for the EXV.

A circulation system of an air conditioner, an air conditioner, and an air conditioner control method. The circulation system of the air conditioner includes a compressor, a first heat exchanger, a second heat exchanger, and a gas-liquid separation assembly. The gas-liquid separation assembly, together with the compressor, the first heat exchanger, and the second heat exchanger, forms a loop; the gas-liquid separation assembly includes two or more gas-liquid separators which are connected in series; the gas-liquid separation assembly is configured to perform gas-liquid separation for refrigerant. Further, two or more-staged gas-liquid separation can be performed for the refrigerant flowing back to the compressor, so that a problem that return oil containing liquid in the compressor can be effectively solved.

A circulation system of an air conditioner, an air conditioner, and an air conditioner control method. The circulation system of the air conditioner includes a compressor, a first heat exchanger, a second heat exchanger, and a gas-liquid separation assembly. The gas-liquid separation assembly, together with the compressor, the first heat exchanger, and the second heat exchanger, forms a loop; the gas-liquid separation assembly includes two or more gas-liquid separators which are connected in series; the gas-liquid separation assembly is configured to perform gas-liquid separation for refrigerant. Further, two or more-staged gas-liquid separation can be performed for the refrigerant flowing back to the compressor, so that a problem that return oil containing liquid in the compressor can be effectively solved.

An exemplary heating, ventilation, and air conditioning (HVAC) system for a building includes a primary heat pump system having a primary heat pump system size, a secondary heat pump system having a secondary heat pump system size less than the primary heat pump system size, a thermal energy storage system, and a control system operable to control operation of the primary heat pump system and the secondary heat pump system. The control system may limit operation of the secondary heat pump system to a first time period, and operates the primary heat pump system according to demand of the building.

An exemplary heating, ventilation, and air conditioning (HVAC) system for a building includes a primary heat pump system having a primary heat pump system size, a secondary heat pump system having a secondary heat pump system size less than the primary heat pump system size, a thermal energy storage system, and a control system operable to control operation of the primary heat pump system and the secondary heat pump system. The control system may limit operation of the secondary heat pump system to a first time period, and operates the primary heat pump system according to demand of the building.

A continuous heating control system and method, and an air-conditioning device. The system includes a defrosting solenoid valve (1) arranged on a bypass pipeline, wherein one end of the bypass pipeline is connected to an oil separator (2), and the other end of the bypass pipeline is connected to an outdoor heat exchanger (3); and a heating structure which is arranged at the bottom of a gas separator (4) and used for heating the gas separator (4).

A continuous heating control system and method, and an air-conditioning device. The system includes a defrosting solenoid valve (1) arranged on a bypass pipeline, wherein one end of the bypass pipeline is connected to an oil separator (2), and the other end of the bypass pipeline is connected to an outdoor heat exchanger (3); and a heating structure which is arranged at the bottom of a gas separator (4) and used for heating the gas separator (4).

A reheating process for operating a cooling system having a heat pump function for a motor vehicle. The reheating process includes steps of determining a heat differential value by comparing a heat emission actual value at the heating register to a heat emission target value, and adjusting at least one operating setting of the cooling system, so that the power consumption in the cooling system is increased if the heat differential value is greater than 0 and less than a heat differential threshold value.