Abstract:
A refrigerating system (2) according to the invention comprises a refrigerating cycle having a compressor (4), a condenser (6), a collecting container (10), an expansion device (16), an evaporator (18) and refrigerating circuits circulating a refrigerant therethrough; a by-pass line (20) comprising a by-pass valve (22), the by-pass line (20) connecting the gas space of the collecting container (10) with the suction line of the compressor (4); and a control unit that in operation allows switching between normal operation of the refrigerating cycle and refrigerant collecting operation in which the by-pass valve (22) is open and reduces the liquefying pressure in the condenser (6) such that the remaining liquid refrigerant in the condenser (6) is evaporated and led into the collecting container (10).
Abstract:
Refrigeration circuit (1, 1') for circulating a refrigerant in a predetermined flow direction through at least one functionally disconnectable component, the refrigeration circuit comprising in flow direction an expansion device (b, b', 26, 26', 33), an evaporator, a compressor (2, 2', 29, 36) and a heat-rejecting heat exchanger (6, 20), wherein an upstream-side shut-off valve is provided upstream of the component and a downstream-side shut-off valve is provided downstream of the component, characterized in that at least one of these shut-off valves is a non-return valve (a, c, 25, 27, 32, 34). Preferably, the component comprises in flow direction the expansion device (b, b', 26, 26', 33) and the evaporator (12, 12', E1, E1', E2) or the compressor (2, 2'). Preferably the non-return valve (a, c, 25, 27, 32, 34) is lockable in it's open position.
Abstract:
A method of controlling a heat-rejection heat exchanging side of a refrigerant circuit comprises the steps of providing a heat-rejection heat exchanging side comprising at least one heat-rejection heat exchanger (4), wherein a refrigerant is cooled against a secondary medium; obtaining a refrigerant condensation temperature (T c ) in the heat-rejection heat exchanging side; obtaining a refrigerant outlet temperature (T ro ); obtaining a secondary medium inlet temperature (T smi ); calculating a relative subcooling value by relating the refrigerant condensation temperature (T c ), the refrigerant outlet temperature (T ro ), and the secondary medium inlet temperature (T smi ); and controlling the relative subcooling value with regard to a reference relative subcooling value.
Abstract:
Die Erfindung betrifft einen Kältekreislauf, in dem ein ein- oder mehrkomponentiges Kältemittel zirkuliert, aufweisend wenigstens eine Entspannungsvorrichtung. Erfindungsgemäß ist die Entspannungsvorrichtung als wenigstens zwei parallel geschaltete Ventile (a, b, c, d) ausgebildet. Ferner betrifft die Erfindung ein Verfahren zum Betreiben eines derartigen Kältekreislaufes. Dieses ist dadurch gekennzeichnet, dass im Falle des Defektes eines der parallel geschalteten Ventile (a, b, c, d) dieses außer Betrieb genommen und das oder wenigstens eines der weiteren Ventile den Regelbetrieb des Kältekreislaufes gewährleistet.
Abstract:
A Refrigerating circuit according to the invention comprises a compressor, a condenser/gas cooler, an expansion device (2), an evaporator (4), and refrigerant conduits circulating a refrigerant therethrough. The evaporator (4) comprises refrigerant piping comprising a plurality of substantially horizontal layers (8, 10) each layer comprising a plurality of pipes (8a-8h, 10a-10h) the pipes being substantially perpendicular to an air flow direction (12) from an air inlet region to an air outlet region of the evaporator (4). A pipe selected from the group of the second pipe (8b) to the last but one pipe (8g) in the bottom layer (8) forms the entry pipe (8c) of the evaporator (4). The entry pipe (8c) is connectable with the expansion device (2) to provide a refrigerating mode, and the entry pipe (8c) is connectable with a hot gas conduit (6) to provide a defrosting mode for the evaporator (4).
Abstract:
A set of piston compressors (2, 4, 6, 8) for use in a refrigeration system comprises a fluid connection (10) between the crank cases of the piston compressors (2, 4, 6, 8) for allowing oil compensation between said piston compressors (2, 4, 6, 8); and a control unit (12) which in operation monitors the running time of each piston compressor (2, 4, 6, 8) and, in case all piston compressors (2, 4, 6, 8) are running, subsequently interrupts the operation of a respective piston compressor (2, 4, 6, 8) for a predetermined period of time for oil compensation if its running time reaches a predetermined maximum running time.
Abstract:
A refrigerating system according to the invention comprises refrigerating cycle having a compressor (4), a condenser (6), a collecting container (10), an expansion device (16), an evaporator (18) and refrigerating circuits circulating a refrigerant therethrough; a liquefying set comprising an additional condenser (24), connected in parallel to the condenser (6); and a control unit that in operation allows switching between normal operation of the refrigerating cycle and refrigerant collecting operation in which the remaining refrigerant is sucked off the condenser (6), is liquefied by the additional condenser (24) and collects in the collecting container (10).
Abstract:
Method for controlling an intermittently supercritically operating refrigeration circuit (2) comprising a compressor (4) a heat-rejecting heat exchanger (10) and a control valve (12) and a control (16), the method comprising the following steps : (a) subcritical mode, controlling the control valve (12) so that a predetermined "supercritical pressure" ensuring a predetermined subcooling of the liquid refrigerant at the outlet (14) of the heat-rejecting heat exchanger (10) is maintained; (b) a supercritical mode, controlling the control; valve (12) so that a predetermined "supercritical pressure" which is optimized for optimum efficiency, of the supercritical refrigerant at the outlet (14) of the heat-rejecting heat exchanger (10) is maintained; and (c) a border mode in a region next to the critical point, controlling the control valve (12) dependent on a "continuity pressure" which is determined on the basis of the predetermined " subcritical pressure" and "supercritical pressure" of steps (a) and (b).
Abstract:
A Refrigerating circuit according to the invention comprises a compressor, a condenser/gas cooler, an expansion device (2), an evaporator (4), and refrigerant conduits circulating a refrigerant therethrough. The evaporator (4) comprises refrigerant piping comprising a plurality of substantially horizontal layers (8, 10) each layer comprising a plurality of pipes (8a-8h, 10a-10h) the pipes being substantially perpendicular to an air flow direction (12) from an air inlet region to an air outlet region of the evaporator (4). A pipe selected from the group of the second pipe (8b) to the last but one pipe (8g) in the bottom layer (8) forms the entry pipe (8c) of the evaporator (4). The entry pipe (8c) is connectable with the expansion device (2) to provide a refrigerating mode, and the entry pipe (8c) is connectable with a hot gas conduit (6) to provide a defrosting mode for the evaporator (4).
Abstract:
A refrigerating system (2) according to the invention comprises a refrigerating cycle having a compressor (4), a condenser (6), a collecting container (10), an expansion device (16), an evaporator (18) and refrigerating circuits circulating a refrigerant therethrough; a by-pass line (20) comprising a by-pass valve (22), the by-pass line (20) connecting the gas space of the collecting container (10) with the suction line of the compressor (4); and a control unit that in operation allows switching between normal operation of the refrigerating cycle and refrigerant collecting operation in which the by-pass valve (22) is open and reduces the liquefying pressure in the condenser (6) such that the remaining liquid refrigerant in the condenser (6) is evaporated and led into the collecting container (10).