Multi-compressor chiller systems can be efficiently operated by determining real time efficiency curves for the compressors currently in operation, along with any compressors that may be added to address demand, and using these efficiency curves to determine changes to compressor operation to improve efficiency in meeting chiller demand. The efficiency curves can be parabolic curves. The data used to determine the efficiency curves can be obtained through operation at a variety of lift points and a variety of load points within those lift points. The efficiency curves can be solved to find intersections where there may be staging points for adding or subtracting compressors from operation to efficiently meet demand. This operation can be automated through a controller of a control system for the multi-compressor chiller system.

A refrigerant-amount determination kit includes a sensor and a processor. The sensor is mounted at least temporarily on at least one of a portion of a refrigeration cycle apparatus and the periphery of the refrigeration cycle apparatus. The refrigeration cycle apparatus is an apparatus having a refrigerant circuit that includes a compressor, a condenser, and an evaporator. The processor determines the amount of a refrigerant in the refrigerant circuit based on a detection result detected by the sensor during operation of the refrigeration cycle apparatus.

A thermal management system that include an electronic circuit boards having at least two circuit boards with a space in between and further includes one or more air tubes or conduits. The electronic circuit board and air tubes are configured for drawing air into the space to facilitate cooling of the electronic circuit board concurrent with cooling of a heat sink of a heat pump connected with the electronic circuit board. The system can further include a partition to isolate airflow from the heat sink from airflow through the electronics circuit board, and can further include one or more interface components for maintaining isolation and control of air flow, improving air intake and/or supporting auxiliary components.

Provided is a heat pump device capable of efficiently adjusting the temperature in a buffer tank for collecting or discharging a refrigerant in a high-pressure space of a refrigerant circulation circuit.

Disclosed is a heat pump device in which a compressor, a gas cooler, a refrigerant heat exchanger, a refrigerant expansion valve, and an evaporator are connected to configure a refrigerant circulation circuit, wherein the heat pump device includes a buffer tank, one end of which is connected to the high-pressure side of the refrigerant expansion valve and arranged to store a refrigerant, and a first refrigerant pipe, one end of which is connected to the high-pressure side of the compressor and the other end of which is connected to the low-pressure side of the evaporator and arranged to exchange heat with the buffer tank, wherein the first refrigerant pipe includes a first control valve arranged between the high-pressure side of the compressor and the buffer tank to control the opening and closing of the first refrigerant pipe, and a first flow rate regulator arranged between the buffer tank and the low-pressure side of the evaporator to control the flow rate of the refrigerant.

Provided is an air-conditioning apparatus including a plurality of indoor units for an outdoor unit, which is capable of determining whether there is occurrence of frost formation on the outdoor unit during a heating operation so as to enable a transition to a defrosting operation at an appropriate timing. Each of the indoor units is configured to transmit an operating-state notification for notifying a self-operating state to the outdoor unit. The outdoor unit is configured to determine the number of indoor units performing the heating operation among the plurality of indoor units based on the operating-state notifications, and determine the occurrence of the frost formation after elapse of a preset time period from a time at which the number of the indoor units performing the heating operation changes.

A multiple-circuit heating and cooling system includes a first refrigeration circuit having a first condenser and a first evaporator and a second refrigeration circuit having a second condenser and a second evaporator. The first condenser and the second condenser are arranged in a first row split configuration, and the second condenser is downstream of the first condenser relative to a first air flow directed across the second condenser and the first condenser. Additionally, the first evaporator and the second evaporator are arranged in a second row split configuration, and the first evaporator is downstream of the second evaporator relative to a second air flow directed across the first evaporator and the second evaporator.

The present disclosure relates to a refrigerator. According to an embodiment of the present disclosure, the refrigerator comprises: an evaporator; a defrost heater; a temperature sensor to sense a temperature around the evaporator; and a controller to control the defrost heater. In response to reaching a defrost operation starting point, the controller is configured to perform a defrost operation mode, perform a continuous operation mode, in which the defrost heater continuously turns on, and a pulsed operation mode, in which the defrost heater switches between on and off, based on the defrost operation mode, wherein in response to performing the pulsed operation mode, the controller is configured to change the ON duration or power level of the defrost heater. Accordingly, defrosting efficiency may be improved, and power consumption may be reduced.

Systems and methods for providing hot water to a commercial dishwasher are provided. A first heat exchanger is provided in a first enclosure, and is used to heat water from a cold water source. The heated water is provided to the commercial dishwasher for use. A second heat exchanger is provided in a second enclosure, and is used to collect waste heat from the wastewater of the commercial dishwasher. A refrigerant coil loop passes through the first heat exchanger and the second heat exchanger, and allows for the use of the waste heat. The first heat exchanger is a condenser provided within a condenser chamber, the condenser connected to a compressor. The second heat exchanger is an evaporator within an evaporator chamber, the evaporator connected to an expansion valve.

A climate-control system can be used to heat or cool a space. The climate-control system may include first and second vessels between which refrigerant and co-fluid may be circulated. The refrigerant may be absorbed into the co-fluid within the first vessel at a first rate. The refrigerant may desorb from the co-fluid within the second vessel at a second rate. Ultrasonic energy may be used to adjust the second rate to substantially match the first rate.

When intended to increase a refrigerant discharge capacity of a compressor in an ejector refrigeration cycle device at start-up of the compressor, the refrigerant discharge capacity is increased in such a manner that an increase amount in the refrigerant discharge capacity of the compressor per predetermined time period is lower than a maximum capacity increase amount per predetermined time period enabled by the compressor. Thus, even if a gas-liquid two-phase refrigerant flows into a refrigerant inflow passage forming a swirling-flow generating portion, the flow velocity of the gas-liquid two-phase refrigerant is prevented from becoming high, so that it can reduce friction noise that would be caused when the gas-liquid two-phase refrigerant circulates through the refrigerant inflow passage, further suppressing the generation of noise from the ejector.