Abstract:
A centrifugal compressor (22) for a chiller (10) includes a casing (30), an inlet guide vane (32), an impeller (34) downstream of the inlet guide vane (32), a motor (38) and a diffuser (36). The casing (30) has inlet and outlet portions with the inlet guide vane (32) disposed in the inlet portion. The impeller (34) is rotatable about a rotation axis (X) defining an axial direction. The motor (38) rotates the impeller (34). The diffuser (36) is disposed in the outlet portion downstream from the impeller (34) with an outlet port of the outlet portion being disposed between the impeller (34) and the diffuser (36). A hot gas injection passage (14) is provided to inject hot gas refrigerant between the inlet guide vane (32) and the impeller (34). A controller (20) is programmed to control an amount of the hot gas refrigerant.
Abstract:
A cooling system (10) for a galley (100) for installation in a transportation means, in particular an aircraft, comprises a cooling device (11) which comprises a coolant circuit (12) adapted to be flown through with a coolant. The cooling system (10) further comprises a fluid line (18) which is adapted to be flown through with a fluid to be cooled and which is thermally coupled with the coolant circuit (12) of the cooling device (11) in order to transfer heat from the fluid to be cooled flowing through the fluid line (18) to the coolant circulating in the coolant circuit (12), and an air line (38) which is adapted to be flown through with air and which is thermally coupled to the coolant circuit (12) of the cooling device (11) in order to transfer heat from the coolant circulating in the coolant circuit (12) to the air line (38). The air line (38), downstream of the thermal coupling of the air line (38) with the coolant circuit (12) of the cooling device (11), is connectable to a cabin region (52) of the transportation means accommodating the galley (100) in order to supply the cabin region (52) with air warmed by heat transfer from the coolant circulating in the coolant circuit (12) of the cooling device (11).
Abstract:
A trolley compartment (10) for an on-board kitchen (100) intended for installation in a means of transport comprises a frontal access aperture (16) as well as a rear wall (18) that lies opposite said access aperture (16). A worktop (14) forms an upper boundary of the trolley compartment (10). A first cooling fluid duct (28) which is connectable to an interior space of the trolley compartment (10) via at least one first cooling fluid aperture (30) is integrated into or arranged adjacent to the worktop (14). At least one first removable cooling fluid aperture cover (40) is selectively mountable in the first cooling fluid duct (28) over the first cooling fluid aperture (30) in order to separate said first cooling fluid duct (28) from the interior space of the trolley compartment (10), or demountable from the first cooling fluid duct (28) in order to connect said first cooling fluid duct (28) to the interior space of the trolley compartment (10) via the first cooling fluid aperture (30).
Abstract:
A method for controlling a vapour compression system, in particular an opening degree of an expansion valve. According to a first control strategy, the expansion valve is closed until the superheat value has increased above a lower threshold superheat value. According to a second control strategy, the expansion valve is kept open until the suction pressure has increased above a lower threshold suction pressure value. In the case of low superheat value as well as low suction pressure, the second control strategy is selected for a limited period of time.
Abstract:
A method for controlling a chiller system (1), the chiller system (1) comprising a primary side in the form of a vapour compression system, and a secondary side, is disclosed. The secondary side comprises a variable speed pump (8) for providing a secondary fluid flow through the evaporator (5) of the primary side in such a manner that heat exchange takes place between refrigerant of the primary side and fluid of the secondary side in the evaporator (5), the secondary side further comprising a temperature sensor (9, 10) arranged in the secondary fluid flow. The method comprises the steps of monitoring a temperature of the secondary fluid flow by means of the temperature sensor (9, 10), and controlling the compressor capacity and the speed of the variable speed pump (8) on the basis of the monitored temperature, and in order to obtain a predetermined setpoint temperature, in such a manner that the closed loop gain of the chiller system (1), K= K p .K e , where K p is the gain of the compressor capacity controller and K e is the gain of the evaporator (5), is kept substantially constant.
Abstract:
A method for controlling a vapour compression system (1) during start-up is disclosed. The rate of change, ΔΤ 1 , of the temperature of refrigerant entering the evaporator (4), and the rate of change, ΔΤ 2 , of the temperature of refrigerant leaving the evaporator (4) are compared. Based on the comparing step, a refrigerant filling state of the evaporator (4) is determined. The opening degree (11) of the expansion device (3) is then controlled according to a first control strategy in the case that it is determined that the evaporator (4) is full or almost full, and according to a second control strategy in the case that it is determined that the evaporator (4) is not full. Thereby it is ensured that a maximum filling degree of the evaporator (4) is quickly reached, without risking that liquid refrigerant passes through the evaporator (4).