The invention provides an air-conditioner for maintaining a temperature of a conditioned space at or near a set temperature. The air-conditioner comprises at least one rotating or reciprocating element adapted to rotate or reciprocate at a variable frequency. The variable frequency including one or more nuisance frequencies at which vibration or noise within the air-conditioner or the conditioned space causes a nuisance. A processor programmed to control variation of the variable frequency in response to operational requirement. The processor is configured to operate the at least one rotating or reciprocating element so as to substantially exclude operation at the one or more nuisance frequencies.

The invention provides an air-conditioner for maintaining a temperature of a conditioned space at or near a set temperature. The air-conditioner comprises at least one rotating or reciprocating element adapted to rotate or reciprocate at a variable frequency. The variable frequency including one or more nuisance frequencies at which vibration or noise within the air-conditioner or the conditioned space causes a nuisance. A processor programmed to control variation of the variable frequency in response to operational requirement. The processor is configured to operate the at least one rotating or reciprocating element so as to substantially exclude operation at the one or more nuisance frequencies.

A sealed refrigerant compressor (10A) accommodates an electric component (20A) and a compression component (30) in a sealed container (11). A crankshaft (40) included in the compression component (30) includes a main shaft part (41) and an eccentric shaft part (42). A main shaft part (41) is secured to a rotor (22A) of the electric component (20A). The rotor (22A) is provided with a balance adjustment means such as a balance hole (27), which adjusts an unbalanced load caused by the structure of the main shaft part (41).

The present disclosure relates to a novel vapor compression refrigeration system, and the methods of making and using the vapor compression refrigeration system.

The present disclosure relates to a novel vapor compression refrigeration system, and the methods of making and using the vapor compression refrigeration system.

The present invention provides a compressor for refrigeration and air conditioning and a refrigeration and air conditioning device capable of achieving both favorable environmental performance and favorable refrigeration cycle efficiency. In the compressor for refrigeration and air conditioning, a refrigerator oil containing a polyol ester and a refrigerant containing difluoromethane are enclosed. The polyol ester has two or more repetitions of poly[2,2-di(alkanoyloxymethyl)oxytrimethylene] as a structural unit. Further, the polyol ester is composed of only one or both of a cyclic polyol ester, which is obtained by cyclically polymerizing a molecular chain having the structural unit, and a crosslinked polyol ester, which is obtained by crosslinking molecular chains having the structural unit with each other through a crosslinkable structural unit polymerized with the structural unit.

A refrigeration device having a closed circuit in which a flow rate of coolant is circulating is provided. The closed circuit has a condenser and a main branch provided with a reciprocating compressor inside which a defined flow rate of the coolant enters, from the main branch, at a defined suction pressure, of an evaporator and a first expansion valve that is arranged between the condenser and the evaporator. The closed circuit further has a first secondary economizer branch for a first fraction of flow rate of the coolant, the first secondary economizer branch fluidically connecting the compressor to a section of the closed circuit between the condenser and the first expansion valve, wherein the compressor has a first side inlet port for the entrance of the first fraction of coolant flow rate.

A refrigeration device having a closed circuit in which a flow rate of coolant is circulating is provided. The closed circuit has a condenser and a main branch provided with a reciprocating compressor inside which a defined flow rate of the coolant enters, from the main branch, at a defined suction pressure, of an evaporator and a first expansion valve that is arranged between the condenser and the evaporator. The closed circuit further has a first secondary economizer branch for a first fraction of flow rate of the coolant, the first secondary economizer branch fluidically connecting the compressor to a section of the closed circuit between the condenser and the first expansion valve, wherein the compressor has a first side inlet port for the entrance of the first fraction of coolant flow rate.

Described are a compressor driving apparatus and a refrigerator including the same. The compressor driving apparatus includes: switching elements; an inverter; an output current detector for detecting an output current flowing through a motor; and an inverter controller for controlling the inverter. The inverter controller controls the piston so that one end of the piston is fixed at a first position spaced apart from the discharge unit at stroke of the piston during a first period, controls the piston to collide with the discharge unit when a change rate in an operation rate or a position error of the compressor is equal to or greater than a predetermined value, and controls the piston so that the one end of the piston is fixed at a second position spaced apart from the discharge unit at stroke of the piston during a second period after the collision of the piston.

Described are a compressor driving apparatus and a refrigerator including the same. The compressor driving apparatus includes: switching elements; an inverter; an output current detector for detecting an output current flowing through a motor; and an inverter controller for controlling the inverter. The inverter controller controls the piston so that one end of the piston is fixed at a first position spaced apart from the discharge unit at stroke of the piston during a first period, controls the piston to collide with the discharge unit when a change rate in an operation rate or a position error of the compressor is equal to or greater than a predetermined value, and controls the piston so that the one end of the piston is fixed at a second position spaced apart from the discharge unit at stroke of the piston during a second period after the collision of the piston.