Patents by Inventor Frede Schmidt

Frede Schmidt has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 12097451
    Abstract: A method for controlling a vapour compression system (1) is disclosed. Malfunctioning of a gas bypass valve (8) is registered. An actual opening degree of the gas bypass valve (8) is derived, and a target opening degree of the gas bypass valve (8) is derived, based on one or more control parameters of the vapour compression system (1). The actual opening degree is compared to the target opening degree, and the vapour compression system (1) is controlled based on the comparison, and in order to match a mass flow of gaseous refrigerant through the gas bypass valve (8) to the actual opening degree of the gas bypass valve (8).
    Type: Grant
    Filed: November 15, 2017
    Date of Patent: September 24, 2024
    Assignee: DANFOSS A/S
    Inventors: Jan Prins, Frede Schmidt, Kenneth Bank Madsen, Kristian Fredslund
  • Publication number: 20240288201
    Abstract: Provided is a refrigeration system for a transport unit. The refrigeration system has a refrigeration cycle comprising a compressor, an evaporator, a condenser fluidically coupled downstream of the compressor and upstream of the evaporator, an expansion valve fluidically coupled downstream of the condenser and upstream of the evaporator, and a suction gas heat exchanger comprising a liquid line side and a suction line side. The liquid line side is fluidically coupled downstream of the condenser and upstream of the expansion valve, and the suction line side is fluidically coupled downstream of the evaporator and upstream of the compressor. The suction gas heat exchanger is configured to transfer heat between refrigerant in the liquid line side and refrigerant in the suction line side.
    Type: Application
    Filed: May 2, 2024
    Publication date: August 29, 2024
    Inventors: Niels Nielsen POULSEN, Poul-Kim MADSEN, Georg Patrick Franz FÖSEL, Marian-Ciprian NICULUTA, Tobias STOLBERG, Frede SCHMIDT
  • Publication number: 20240280297
    Abstract: Provided is a cascade refrigeration system for a transport unit. The cascade refrigeration system has a first refrigeration cycle comprising a first compressor and a first expansion valve, a second refrigeration cycle comprising a second compressor and a second expansion valve, and a cascade heat exchanger. The cascade heat exchanger comprises a condenser side fluidically coupled downstream of the first compressor and upstream of the first expansion valve, and an evaporator side fluidically coupled downstream of the second expansion valve and upstream of the second compressor. The cascade refrigeration system also comprises a pre-cooler comprising a first side and a second side. The first side is fluidically coupled downstream of the first compressor and upstream of the condenser side of the cascade heat exchanger, and the pre-cooler is configured to transfer heat between refrigerant in the first side and refrigerant in the second side.
    Type: Application
    Filed: May 1, 2024
    Publication date: August 22, 2024
    Inventors: Niels Nielsen POULSEN, Tobias STOLBERG, Marian-Ciprian NICULUTA, Poul-Kim MADSEN, Georg Patrick Franz FÖSEL, Frede SCHMIDT
  • Patent number: 11460230
    Abstract: A method for controlling a vapour compression system (1) is disclosed, the vapour compression system (1) comprising at least one expansion device (8) and at least one evaporator (9). For each expansion device (8), an opening degree of the expansion device (8) is obtained, and a representative opening degree, ODrep, is identified based on the obtained opening degree(s) of the expansion device(s) (8). The representative opening degree could be a maximum opening degree, ODmax, being the largest among the obtained opening degrees. The representative opening degree, ODrep, is compared to a predefined target opening degree, ODtarget, and a minimum setpoint value, SPrec, for a pressure prevailing inside a receiver (7), is calculated or adjusted, based on the comparison. The vapour compression system (1) is controlled to obtain a pressure inside the receiver (7) which is equal to or higher than the calculated or adjusted minimum setpoint value, SPrec.
    Type: Grant
    Filed: October 14, 2016
    Date of Patent: October 4, 2022
    Assignee: Danfoss A/S
    Inventors: Jan Prins, Frede Schmidt, Kenneth Bank Madsen, Kristian Fredslund
  • Patent number: 11340000
    Abstract: A method for controlling a vapour compression system (1) is disclosed. A mass flow of refrigerant along a part of the refrigerant path is estimated, based on measurements performed by one or more pressure sensors (10, 12, 13) for measuring a refrigerant pressure at selected positions along the refrigerant path and one or more temperature sensors (11, 14) for measuring a refrigerant temperature at selected positions along the refrigerant path. A refrigerant pressure or a refrigerant temperature at a selected position a pressure sensor (10, 12, 13) or temperature sensor (11, 14) along the refrigerant path is derived, based on the estimated mass flow. The vapour compression system (1) is allowed to continue operating, even if a sensor (10, 11, 12, 13, 14) is malfunctioning or unreliable.
    Type: Grant
    Filed: November 15, 2017
    Date of Patent: May 24, 2022
    Assignee: Danfoss A/S
    Inventors: Frede Schmidt, Jan Prins, Kristian Fredslund, Kenneth Bank Madsen
  • Patent number: 11060767
    Abstract: A method for operating a compressor unit (2) comprising one or more compressors (8, 9, 10) is disclosed, the compressor unit (2) being arranged in a vapour compression system (1). Two or more options for distributing the available compressor capacity of the compressor unit (2) between being connected to a high pressure suction line (11) and to a medium pressure suction line (13) are defined. For each option, an expected impact on one or more operating parameters of the vapour compression system (1), resulting from distributing the available compressor capacity according to the option, is predicted. An option is selected, based on the predicted expected impact for the options, and based on current operating demands of the vapour compression system (1), and the available compressor capacity is distributed according to the selected option, e.g. by means of settings of one or more valve arrangements (14, 15).
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: July 13, 2021
    Assignee: DANFOSS A/S
    Inventors: Kristian Fredslund, Jan Prins, Kenneth Madsen, Frede Schmidt
  • Patent number: 10962262
    Abstract: A method for controlling a vapour compression system (1) is disclosed, the vapour compression system (1) comprising at least one compressor (2, 16), a heat rejecting heat exchanger (3), a high pressure expansion device (4, 15, 17), a receiver (5), an evaporator expansion device (6), an evaporator (7) and a gas bypass valve (8), arranged in a refrigerant path. It is registered that the gas bypass valve (8) is malfunctioning or saturated, and a pressure value for a pressure prevailing inside the receiver (5) is obtained. Finally, the vapour compression system (1) is controlled in order to control a gaseous refrigerant supply to the receiver (5) to adjust the pressure prevailing inside the receiver (5) to reach a target pressure level.
    Type: Grant
    Filed: November 15, 2017
    Date of Patent: March 30, 2021
    Assignee: Danfoss A/S
    Inventors: Kristian Fredslund, Kenneth Bank Madsen, Jan Prins, Frede Schmidt
  • Patent number: 10941964
    Abstract: A method for controlling a vapour compression system, the vapour compression system including a compressor unit with one or more compressors. At least one of the compressors is connectable to a gaseous outlet of a receiver, and at least one of the compressors is connectable to an outlet of an evaporator. A parameter of the vapour compression system is measured, an enthalpy of refrigerant leaving the heat rejecting heat exchanger being derivable from the measured parameter. A setpoint value for a pressure inside the receiver is calculated, based on the measured parameter, and the compressor unit is operated in accordance with the calculated setpoint value, and in order to obtain a pressure inside the receiver which is equal to the calculated setpoint value. The vapour compression system is operated in an energy efficient manner over a wide range of ambient temperatures.
    Type: Grant
    Filed: October 7, 2015
    Date of Patent: March 9, 2021
    Assignee: Danfoss A/S
    Inventors: Kristian Fredslund, Frede Schmidt, Kenneth Bank Madsen, Jan Prins
  • Patent number: 10928107
    Abstract: A method for operating a vapour compression system (1) comprising a heat recovery heat exchanger (4) is disclosed. The heat recovery system requests a required level of recovered heat to be provided by the heat recovery heat exchanger (4) to the heat recovery system, generates a signal indicating the required level of recovered heat, and supplies the generated signal to a control unit of the vapour compression system (1). A setpoint value for at least one control parameter of the vapour compression system (1) is calculated, based on the generated signal, and the vapour compression system (1) is operated in accordance with the calculated setpoint value(s).
    Type: Grant
    Filed: May 25, 2016
    Date of Patent: February 23, 2021
    Assignee: Danfoss A/S
    Inventors: Frede Schmidt, Kristian Fredslund, Jan Prins
  • Patent number: 10816245
    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).
    Type: Grant
    Filed: July 1, 2016
    Date of Patent: October 27, 2020
    Assignee: DANFOSS A/S
    Inventors: Jan Prins, Frede Schmidt, Kenneth Bank Madsen, Kristian Fredslund
  • Patent number: 10775086
    Abstract: A method for controlling a vapour compression system having an ejector includes, in the case that a pressure difference between a pressure prevailing in the receiver and a pressure of refrigerant leaving the evaporator decreases below a first lower threshold value, the pressure of refrigerant leaving the heat rejecting heat exchanger is kept at a level which is slightly higher than the pressure level providing optimal coefficient of performance.
    Type: Grant
    Filed: October 14, 2016
    Date of Patent: September 15, 2020
    Assignee: DANFOSS A/S
    Inventors: Jan Prins, Frede Schmidt, Kenneth Bank Madsen, Kristian Fredslund
  • Patent number: 10724778
    Abstract: A method for controlling a fan (6) of a vapour compression system (1) is disclosed, the fan (6) being arranged to provide a secondary fluid flow across a heat rejecting heat exchanger (3). A temperature difference, ?T=Tout?Tamb, between a temperature, Tout, of refrigerant leaving the heat rejecting heat exchanger (3) and a temperature, Tamb, of ambient air of the heat rejecting heat exchanger (3) is established. A setpoint value, ?Tsetp, for the temperature difference, ?T, is obtained, the setpoint value, ?Tsetp, being dependent on the fan speed of the fan (6) in such a manner that the setpoint value, ?Tsetp, increases as the fan speed increases. The fan speed of the fan (6) is controlled in order to control the temperature difference, ?T, in accordance with the obtained setpoint value, ?Tsetp.
    Type: Grant
    Filed: February 3, 2017
    Date of Patent: July 28, 2020
    Assignee: DANFOSS A/S
    Inventors: Kristian Fredslund, Frede Schmidt, Jan Prins
  • Patent number: 10563892
    Abstract: A level sensor is configured to provide a receiver level indicating an amount of the refrigerant present in the receiver and a level model provides a heat rejecting heat exchanger estimate indicating an amount of the refrigerant present in the heat rejecting heat exchanger based on a temperature of the refrigerant. From the sensor and the model, a loss of refrigerant from the refrigerant vapor compression system is estimated.
    Type: Grant
    Filed: August 21, 2015
    Date of Patent: February 18, 2020
    Assignee: Danfoss A/S
    Inventors: Frede Schmidt, Kristian Fredslund, Jan Prins
  • Patent number: 10544971
    Abstract: A method for controlling a vapor compression system (1) is disclosed, the vapor compression system (1) comprising an ejector (5). The method comprises controlling a compressor unit (2) in order to adjust a pressure inside a receiver (6), on the basis of a detected pressure of refrigerant leaving an evaporator (8). The portion of refrigerant leaving the evaporator (8) which is supplied to a secondary inlet (15) of the ejector is maximized and the portion of refrigerant supplied directly to the compressor unit (2) is minimized, while ensuring that the pressure of refrigerant leaving the evaporator (8) does not decrease below an acceptable level.
    Type: Grant
    Filed: October 7, 2015
    Date of Patent: January 28, 2020
    Assignee: DANFOSS A/S
    Inventors: Kristian Fredslund, Frede Schmidt, Kenneth Bank Madsen, Jan Prins
  • Patent number: 10508850
    Abstract: A vapour compression system (1) includes an ejector (6) and a liquid separating device (10) arranged in a suction line. At least one evaporator (9) is allowed to be operated in a flooded state. A flow rate of refrigerant from the liquid separating device (10) to the secondary inlet (15) of the ejector (6) is detected, and it is determined whether or not the flow rate is sufficient to remove liquid refrigerant produced by the evaporator(s) (9) from the liquid separating device (10). In the case that it is determined that the flow rate of refrigerant from the liquid separating device (10) to the secondary inlet (15) of the ejector (6) is insufficient to remove liquid refrigerant produced by the evaporator(s) (9), the flow rate of refrigerant from the liquid separating device (10) to the secondary inlet (15) of the ejector (6) is increased, and/or a flow rate of liquid refrigerant from the evaporator(s) (9) to the liquid separating device (10) is decreased.
    Type: Grant
    Filed: October 14, 2016
    Date of Patent: December 17, 2019
    Assignee: Danfoss A/S
    Inventors: Jan Prins, Frede Schmidt, Kenneth Bank Madsen, Kristian Fredslund
  • Publication number: 20190323752
    Abstract: A method for controlling a fan (6) of a vapour compression system (1) is disclosed, the fan (6) being arranged to provide a secondary fluid flow across a heat rejecting heat exchanger (3). A temperature difference, ?T=Tout?Tamb, between a temperature, Tout, of refrigerant leaving the heat rejecting heat exchanger (3) and a temperature, Tamb, of ambient air of the heat rejecting heat exchanger (3) is established. A setpoint value, ?Tsetp, for the temperature difference, ?T, is obtained, the setpoint value, ?Tsetp, being dependent on the fan speed of the fan (6) in such a manner that the setpoint value, ?Tsetp, increases as the fan speed increases. The fan speed of the fan (6) is controlled in order to control the temperature difference, ?T, in accordance with the obtained setpoint value, ?Tsetp.
    Type: Application
    Filed: February 3, 2017
    Publication date: October 24, 2019
    Inventors: Kristian Fredslund, Frede Schmidt, Jan Prins
  • Publication number: 20190301773
    Abstract: A method for controlling a vapour compression system (1) is disclosed, the vapour compression system (1) comprising at least one compressor (2, 16), a heat rejecting heat exchanger (3), a high pressure expansion device (4, 15, 17), a receiver (5), an evaporator expansion device (6), an evaporator (7) and a gas bypass valve (8), arranged in a refrigerant path. It is registered that the gas bypass valve (8) is malfunctioning or saturated, and a pressure value for a pressure prevailing inside the receiver (5) is obtained. Finally, the vapour compression system (1) is controlled in order to control a gaseous refrigerant supply to the receiver (5) to adjust the pressure prevailing inside the receiver (5) to reach a target pressure level.
    Type: Application
    Filed: November 15, 2017
    Publication date: October 3, 2019
    Inventors: Kristian Fredslund, Kenneth Bank Madsen, Jan Prins, Frede Schmidt
  • Publication number: 20190301780
    Abstract: A method for controlling a vapour compression system (1) is disclosed. A mass flow of refrigerant along a part of the refrigerant path is estimated, based on measurements performed by one or more pressure sensors (10, 12, 13) for measuring a refrigerant pressure at selected positions along the refrigerant path and one or more temperature sensors (11, 14) for measuring a refrigerant temperature at selected positions along the refrigerant path. A refrigerant pressure or a refrigerant temperature at a selected position a pressure sensor (10, 12, 13) or temperature sensor (11, 14) along the refrigerant path is derived, based on the estimated mass flow. The vapour compression system (1) is allowed to continue operating, even if a sensor (10, 11, 12, 13, 14) is malfunctioning or unreliable.
    Type: Application
    Filed: November 15, 2017
    Publication date: October 3, 2019
    Inventors: Frede Schmidt, Jan Prins, Kristian Fredslund, Kenneth Bank Madsen
  • Publication number: 20190299132
    Abstract: A method for controlling a vapour compression system (1) is disclosed. Malfunctioning of a gas bypass valve (8) is registered. An actual opening degree of the gas bypass valve (8) is derived, and a target opening degree of the gas bypass valve (8) is derived, based on one or more control parameters of the vapour compression system (1). The actual opening degree is compared to the target opening degree, and the vapour compression system (1) is controlled based on the comparison, and in order to match a mass flow of gaseous refrigerant through the gas bypass valve (8) to the actual opening degree of the gas bypass valve (8).
    Type: Application
    Filed: November 15, 2017
    Publication date: October 3, 2019
    Inventors: Jan Prins, Frede Schmidt, Kenneth Bank Madsen, Kristian Fredslund
  • Publication number: 20190264962
    Abstract: A method for controlling a valve arrangement (10) interconnecting at least one oil separator (8) and an oil receiver (9) in a vapour compression system (1) is disclosed. A pressure difference between a pressure prevailing inside the oil separator(s) (8) and a pressure prevailing inside the oil receiver (9) is obtained. Then a duration for an open time of an open/close sequence of the valve arrangement (10) is derived, based on the obtained pressure difference, and the valve arrangement (10) is controlled in accordance with the derived duration of an open time. The supply of oil to the oil receiver (9) can be accurately controlled, regardless of the operating conditions.
    Type: Application
    Filed: June 21, 2017
    Publication date: August 29, 2019
    Applicant: Danfoss A/S
    Inventors: Flemming Morten Schmidt, Jan Prins, Frede Schmidt, Kristian Fredslund