Vapour compression system with at least two evaporator groups
AssigneeDanfoss A/S
InventorsJan Prins, Frede Schmidt, Kenneth Bank Madsen, Kristian Fredslund
Life of this patent
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Abstract
A method for controlling a vapour compression system in an energy efficient and stable manner, the vapour compression system (1) including at least two evaporator groups (5a, 5b, 5c), each evaporator group (5a, 5b, 5c) including an ejector unit (7a, 7b, 7c), at least one evaporator (9a, 9b, 9c) and a flow control device (8a, 8b, 8c) controlling a flow of refrigerant to the at least one evaporator (9a, 9b, 9c). For each evaporator group (5a, 5b, 5c) the outlet of the evaporator (9a, 9b, 9c) is connected to a secondary inlet (12a, 12b, 12c) of the corresponding ejector unit (7a, 7b, 7c).
Claims16
A method for controlling a vapour compression system comprising a compressor group comprising one or more compressors, a heat rejecting heat exchanger, a receiver, and at least two evaporator groups, each evaporator group comprising an ejector unit, at least one evaporator and a flow control device controlling a flow of refrigerant to the at least one evaporator, wherein an outlet of the heat rejecting heat exchanger is connected to a primary inlet of the ejector unit of each of the evaporator groups, an outlet of each ejector unit is connected to an inlet of the receiver, and an outlet of the at least one evaporator of each evaporator group is connected to a secondary inlet of the ejector unit of the corresponding evaporator group, the method comprising the steps of:
- obtaining a pressure of a refrigerant leaving the heat rejecting heat exchanger,
- for at least one evaporator group, obtaining a value for an operating parameter related to that at least one evaporator group, and
- controlling at least one ejector unit of the at least two evaporator groups in accordance with the obtained pressure of the refrigerant leaving the heat rejecting heat exchanger or in accordance with the obtained value for the operating parameter,
- wherein the operating parameter of the at least one evaporator group of the least two evaporator groups is a parameter reflecting a quantity of refrigerant flowing through the at least one evaporator of the at least one evaporator group, which is not evaporated.
A method for controlling a vapour compression system comprising a compressor group comprising one or more compressors, a heat rejecting heat exchanger, a receiver, and at least two evaporator groups, each evaporator group comprising an ejector unit, at least one evaporator and a flow control device controlling a flow of refrigerant to the at least one evaporator, wherein an outlet of the heat rejecting heat exchanger is connected to a primary inlet of the ejector unit of each of the evaporator groups, an outlet of each ejector unit is connected to an inlet of the receiver, and an outlet of the at least one evaporator of each evaporator group is connected to a secondary inlet of the ejector unit of the corresponding evaporator group, the method comprising the steps of:
- obtaining a pressure of a refrigerant leaving the heat rejecting heat exchanger,
- for at least one evaporator group, obtaining a value for an operating parameter related to that at least one evaporator group, and
- controlling at least one ejector unit of the at least two evaporator groups in accordance with the obtained pressure of the refrigerant leaving the heat rejecting heat exchanger or in accordance with the obtained value for the operating parameter,
- wherein the step of controlling the at least one ejector unit comprises the steps of:
- determining whether the total capacity of the ejector units of the least two evaporator groups needs to be increased, decreased or maintained, based on the obtained pressure of refrigerant leaving the heat rejecting heat exchanger,
- when the total capacity of the ejector units of the least two evaporator groups needs to be increased or decreased, selecting at least one evaporator group of the least two evaporator groups, based on the obtained value for the operating parameter, and
- increasing or decreasing the capacity of the ejector unit of the selected at least one evaporator group, and
- wherein the step of selecting at least one evaporator group of the least two evaporator groups comprises the steps of:
- comparing the obtained value for the operating parameter to a corresponding reference value,
- when the total capacity of the ejector units of the least two evaporator groups needs to be increased, selecting the evaporator group of the least two evaporator groups having the largest deviation between the obtained value for the operating parameter and the reference value, and
- when the total capacity of the ejector units of the least two evaporator groups needs to be decreased, selecting the evaporator group of the least two evaporator groups having the smallest deviation between the obtained value for the operating parameter and the reference value.
Dependencies are inferred from the claim text.