In order to improve the operational reliability of a refrigerant compressor system that includes a first refrigerant line that conducts expanded refrigerant, a second refrigerant line that conducts compressed refrigerant, at least one refrigerant compressor that is arranged between the first and the second refrigerant line and is driven by a motor, and a control unit for operating the refrigerant compressor system, it is proposed that the control unit should have a first central processing unit and at least one input/output unit for control variables that communicates with the first central processing unit, and that there should be associated with the first central processing unit a second central processing unit which, in the event of a failure of the first central processing unit, takes over the control functions for the purpose of controlling the refrigerant compressor system.

A multi-type air conditioning device controls an evaporation temperature and a condensing temperature, depending on required capacity of an indoor unit. The air conditioning device compares a current evaporation temperature or condensing temperature with a reference value, of an evaporation temperature or an condensing temperature, corresponding to a lower limit flow rate, of a gaseous refrigerant, required for refrigerating machine oil not to accumulate in, but to flow through, the gas branch pipes, and calculates an amount of the refrigerating machine oil accumulated in a gas branch pipe which does not satisfy the lower limit flow rate. When the calculated amount exceeds a set amount, the air conditioning device performs oil collecting operation, and controls the oil collecting operation in view of a flow rate of a gaseous refrigerant in gas branch pipes.

The present invention discloses a refrigerator controlling method and system with a linear compressor. The method comprises: monitoring an environment temperature T of the refrigerator located in the environment comparing the environment temperature T with a preset environment temperature threshold T0; if T is larger than T0, controlling a refrigerating unit and/or a heating unit in the refrigerator such that the refrigerator runs under a first operation condition; and if T is smaller than or equal to T0, controlling the refrigerating unit and/or the heating unit in the refrigerator such that the refrigerator runs under a second operation condition. When the linear compressor runs within predetermined time, a refrigeration amount of the linear compressor under the second operation condition is controlled to be larger than a refrigeration amount of the linear compressor under the first operation condition, such that a compartment of the refrigerator reaches a target temperature.

A refrigerator includes a first compressor configured to compress first refrigerant, a first condenser configured to condense the compressed first refrigerant, a first expansion valve configured to reduce a temperature and a pressure of the condensed first refrigerant, a first evaporator configured to evaporate the first refrigerant having passed through the first expansion valve, a second compressor configured to compress second refrigerant, a second condenser configured to condense the compressed second refrigerant, a second expansion valve configured to reduce a temperature and a pressure of the condensed second refrigerant, a second evaporator configured to evaporate the second refrigerant having passed through the second expansion valve, a first heat exchanger arranged after and connected to the first expansion valve, and a second heat exchanger arranged after and connected to the second expansion valve. The first heat exchanger and the second heat exchanger are configured to exchange heat with each other.

Described is a vector control system for a vapor compression circuit. The vector control system may monitor the vapor compression circuit and adjust the speed of one or more motors to increase efficiency by taking into account the torque forces placed on a compressor motor.

A heat transfer unit includes: an electrical component casing defining an internal space, the internal space housing a transformer together with a control board and a power supply board; and a cooling unit which cools an electronic component on the power supply board during operation of a compressor.

A thermal management system for an enclosure containing electrical components includes a cooling unit for controlling temperature inside the enclosure and a controller for the cooling unit, the controller being configured so that it can receive a three-phase power input signal and distribute power and control connected components using the three-phase signal. The controller can protect the compressor in critical scenarios such as thermal overload and overcurrent. The controller can output various faults such as missing phase alarm, imbalance phase alarm, overcurrent alarm, thermal overload alarm, door open alarm, and temperature and pressure alarms. An auto phase sequence correction controls the phase relay, accepting 3 phase 480 VAC power input from facility power terminal, supplying 3 phase power to the compressor and motor impellers, 12V DC power to a display unit, and 24V DC power to a remote access control module.

A method includes measuring a saturated suction temperature, receiving actual temperature value reflective of the measured saturated suction temperature, and determining whether the actual temperature value is less than a first pre-determined minimum threshold temperature value. If the actual temperature value is less than the first pre-determined minimum threshold temperature value, initiating a timer to operate for a pre-determined time interval. Determining whether the actual temperature value is less than a second pre-determined minimum threshold temperature value and if the actual temperature value is less the second pre-determined minimum threshold temperature value, initiating the timer to operate for a modified time interval. If the timer has expired, the operation of the compressor is modified.

In order to improve a method for operating status determination of a refrigerant compressor/expander comprising a compressor unit and a drive unit such that information on the operating status of a refrigerant compressor/expander which is as reliable as possible can be obtained, it is proposed that, for at least one bearing of the refrigerant compressor/expander, a load value resulting from an operation of said refrigerant compressor/expander and a speed value are determined and in that, on the basis of the speed value and the load value and also at least one operating parameter, there is determined for the at least one bearing an operating prediction value for a future maintenance-free operation of the refrigerant compressor/expander.

A system includes a dynamic compressor and a controller having a processor and a memory. The compressor includes a first compressor stage having a first variable inlet guide vane (VIGV) and a second compressor stage having a second VIGV. The memory stores instructions that program the processor to operate the compressor at a current speed, a first position of the first VIGV, and a second position of the second VIGV to compress the working fluid, and to determine if a condition is satisfied. If the condition is not satisfied, the processor is programmed to continue to operate the compressor at the current speed, the first position of the first VIGV, and the second position of the second VIGV. If the condition is satisfied, the processor is programmed to change the second position of the second VIGV to a third position and maintain the first position of the first VIGV.