Danfoss A/s

Claus Thybo

Lars Finn Sloth Larsen

Leo Bram

Honglian Thybo

Ole Ploug

Roozbeh Izadi-Zamanabadi

Bjarne Dindler Rasmussen

Jakob Spangberg

Asbjoern Leth Vonsild

Rafael Wisniewski

Jens Pawlik

Jes V Vogler

Christian Bendtsen

Roozbeh Izadi-Zamanabad

Steen Lauridsen

Jesper Hoeyer

Gunda Mader

Ejner Kobberoe

Vagn Helberg

Helge Vandel Jensen

Atli Benonysson

Oddgeir Gudmundsson

Ejner KobberØ

An expansion valve () comprising an inlet opening () and a distributor () being arranged to distribute fluid medium received from the inlet opening to at least two parallel flow paths (). At least two outlet openings () are adapted to deliver fluid in an at least partially gaseous state, and each outlet opening is fluidly connected to one of the parallel flow paths. A first valve part () and a second valve part () are arranged movably relative to each other in such a manner that the mutual position of the first valve part and the second valve part determines the opening degree of the expansion valve. Since the distributor () forms part of the expansion valve, it distributes the fluid medium to the parallel flow paths prior to or during expansion of the fluid medium, i.e. while the fluid medium is in a substantially liquid state. This makes it easier to control the distribution of fluid medium to the parallel flow paths in a uniform manner.

Expansion valve with a distributor

A method for controlling a supply of refrigerant to an evaporator () of a vapor compression system (), such as a refrigeration system, an air condition system or a heat pump, is disclosed. The vapor compression system () comprises an evaporator (), a compressor (), a condenser () and an expansion device () arranged in a refrigerant circuit. The method comprises the steps of: Actuating a component, such as an expansion valve (), a fan or a compressor (), of the vapor compression system () in such a manner that a dry zone in the evaporator () is changed; measuring a temperature signal representing a temperature of refrigerant leaving the evaporator (); analyzing the measured temperature signal, e.g. including deriving a rate of change signal; determining a temperature value where a gain of a transfer function between the actuated component and the measured temperature drops from a maximum value to a minimum value, in a decreasing temperature direction; defining the determined temperature value as corresponding to a zero superheat (SH=0) value of refrigerant leaving the evaporator (), and controlling a supply of refrigerant to the evaporator () in accordance with the defined SH=0 temperature value, and on the basis of the measured temperature signal. The method steps may be repeated at certain time intervals in order to provide updated determinations of the SH=0 temperature value. The method allows the SH=0 point to be determined purely on the basis of the measured temperature signal. Subsequently, the supply of refrigerant to the evaporator () can be controlled purely on the basis of the measured temperature signal.

Method for controlling a supply of refrigerant to an evaporator

A method for determining wire connections in a vapor compression system () is disclosed. The vapor compression system comprises a compressor, a condenser, an expansion device () and an evaporator () being fluidly interconnected in a refrigerant path, and two or more sensor devices () arranged for measuring variables which are relevant for the operation of the vapor compression system (). The method comprises the steps of changing an operational setting, e.g. an opening degree of the expansion device () for the vapor compression system (), monitoring variable values, such as temperatures, being measured by at least two sensor devices (), e.g. arranged at various positions of the vapor compression system (), in response to said changed operational setting, comparing the measured variable values to expected behavior of at least one variable measured by a sensor device () in response to said changed operational setting, and based on the comparing step, determining at least one wire connection of the vapour compression system (). The method allows correct wire connections to be established without any special effort from the installing personnel, and without requiring rewiring of the system.

Method for determining wire connections in a vapour compression system

A method for controlling a vapor compression system, such as a refrigeration system, preferably an air condition system, comprising at least two evaporators. While monitoring a superheat (SH) at a common outlet for the evaporators, the amount of available refrigerant is controlled in response to the SH and in order to obtain an optimum SH value. The available refrigerant is distributed among the evaporators in accordance with a distribution key. The distribution key is preferably obtained while taking individual consideration to operating conditions for each of the evaporators into account. Thereby the vapor compression system can be operated in such a way that each of the evaporators is operated in an optimal manner, and in such a way that the system in general is operated in an optimal manner.

Method for controlling a vapour compression system

A valve comprising an inlet opening adapted to receive fluid medium and at least two outlet openings, each being fluidly connected to a flow path being arranged fluidly in parallel, is disclosed. The valve comprises a first valve part () and a second valve part (). The first valve part () has at least two flow passages () formed therein, each flow passage () being fluidly connected to one of the outlet openings. The second valve part () has at least one primary flow passage () and at least one secondary flow passage () formed therein, the primary flow passage(s) () and the secondary flow passage(s) () being fluidly connected to the inlet opening. The first valve part () and the second valve part () are movable relative to each other in such a manner that the mutual position of the first valve part () and the second valve part () determines a fluid flow between the inlet opening and each of the outlet openings, via the flow passages () of the first valve part () and the second valve part ().

Valve for a vapour compression system

The present invention relates to a method and a system to reduce losses of energy due to ripples, especially at the power grid, the ripples being short term power shortages or excess power. The method is based on the idea of shutting off energy consuming devices during a period of power shortage, if their operation is not necessary, and optionally to turn on such energy consuming devices during periods of excess power, if energy may be stored in them, especially when energy may be stored as some physical parameter or variable, being a part of the operation of the energy consuming devices, such as the temperature of a freezer.

Power saving system and method for a refrigeration system, providing for short term response to reduce ripples on a power grid

A refrigeration system includes an expansion valve and a compressor, the expansion valve, the evaporator and the compressor being arranged in a refrigerant flow path having refrigerant flowing therein. A method for controlling a flow of refrigerant to an evaporator includes steps of increasing an opening degree of the expansion valve, thereby increasing a flow of refrigerant to the evaporator sufficiently to substantially eliminate a dry zone of the evaporator, decreasing the opening degree of the expansion valve, and repeating the steps of increasing and decreasing. This causes the superheat value of refrigerant leaving the evaporator to 'toggle' between a zero level and a low, but positive, level. Thereby the refrigeration capacity is utilized more efficiently. Additionally, sufficiently low amount of liquid refrigerant is allowed to pass through the evaporator to prevent damage to the compressor.

Method for controlling a flow of refrigerant to an evaporator

An expansion valve for a vapor compression system comprises a first valve member and a second valve member. The first valve member and the second valve member are arranged movably relative to each other, and the relative position of the first valve member and the second valve member determines an opening degree of the expansion valve. The first valve member and/or the second valve member is/are automatically movable in response to changes in a differential pressure across the expansion valve, the opening degree of the expansion valve thereby being automatically altered in response to changes in the differential pressure across the expansion valve. It is ensured that the opening degree of the expansion valve is automatically adjusted to the actual operating conditions, thereby optimising the efficiency of the vapour compression system.

Expansion valve with variable opening degree

A method of estimating a floor temperature of a solid floor that has a fluid conduit embedded in the floor. Provided is a control scheme that provides a sequence, where the concrete temperature can be estimated through the temperature of the fluid in the conduit embedded in the floor. After the concrete temperature is obtained, a heating sequence can be initiated for providing fast and accurate control of the floor temperature.

Method of estimating a floor temperature of a solid floor

An expansion device unit () for a vapor compression system (), and a vapor compression system () are disclosed. The expansion device unit () comprises an inlet opening () arranged to receive fluid medium, at least two outlet openings () arranged to deliver fluid medium, a main expanding section () adapted to expand fluid medium received via the inlet opening () before delivering the fluid medium to the outlet openings (), and a distribution section () arranged to split the fluid flow received via the inlet opening () into at least two fluid flows to be delivered via the outlet openings (). The main expanding section () and/or the distribution section () is/are arranged to cause pressures in fluid delivered via at least two of the outlet openings () to be distinct. The main expanding section () is operated on the basis of one or more parameters measured in the fluid flow delivered by one of the outlet openings (). The distinct pressure levels allow distinct evaporating temperature in evaporator paths () connected to the outlet openings (). Thereby a large temperature difference between inlet temperature and outlet temperature of a secondary fluid flow across the evaporator () can be obtained, without requiring that the entire mass flow must be compressed from a low pressure level by the compressor (). Thereby energy is conserved.

Expansion unit for a vapour compression system

A valve including a first valve part with at least one opening and a second valve part with at least one opening. The relative position of the openings of the first and second valve parts produces an overlapping area, which defines an opening degree of the valve. The first and second valve parts are adapted to perform relative movements from a position defining a maximum opening degree of the valve towards a position defining a minimum opening degree of the valve in such a manner that the velocity of the relative movement between the first valve part and the second valve part varies as a function of the overlapping area of the openings of the first and second valve parts. For example, the velocity may be decreased as the overlapping area decreases. Operating the valve in this manner reduces water hammering while ensuring appropriate operation and acceptable response times.

Method for operating a valve

A method for calibrating a superheat sensor () for a refrigeration system is provided. The method comprises the following steps. Increasing an amount of liquid refrigerant in the evaporator (), e.g. by increasing an opening degree of the expansion valve (). Monitoring one or more parameters, e.g. the temperature of refrigerant leaving the evaporator (), said parameters reflecting a superheat value of the refrigerant. Allowing the value of each of the parameter(s) to decrease. When the value(s) of the monitored parameter(s) reaches a substantially constant level, defining the superheat value corresponding to the constant level to be SH=0. The superheat sensor () is then calibrated in accordance with the defined SH=0 level. When the parameter(s) reaches the substantially constant level it is an indication that liquid refrigerant is allowed to pass through the evaporator (), and thereby that the superheat of the refrigerant leaving the evaporator () is zero. Calibration can be performed on site, and it is therefore not necessary to calibrate the sensor () at the manufacturing facility. Thereby it is no longer required to match calibration information with a specific sensor.

Method for calibrating a superheat sensor

A method of analyzing and controlling a refrigeration system () including at least one compressor (), at least one condenser () and at least two refrigeration entities (), each having at least one evaporator (), includes preventing or reducing evaporator synchronization. Based on information received from the evaporator valve control units by a central control unit (), it is determined whether or not two or more evaporators () are running in a synchronized manner and the refrigeration system () is controlled in order to desynchronize the evaporators () when two or more evaporators () are running in a synchronized manner.

Method of analysing a refrigeration system and a method of controlling a refrigeration system

A superheat sensor () for sensing superheat of a fluid flowing in a flow channel () is disclosed. The sensor () comprises a flexible wall defining an interface between an inner cavity () having a charge fluid () arranged therein and the flow channel (). The flexible wall is arranged in the flow channel () in thermal contact with the fluid flowing therein, and the flexible wall is adapted to conduct heat between the flow channel () and the inner cavity (). Thereby the temperature of the charge fluid () adapts to the temperature of the fluid flowing in the flow channel (), and the pressure in the inner cavity () is determined by this temperature. A first wall part () and a second wall part () are arranged at a variable distance from each other, said distance being defined by a differential pressure between the pressure of the charge fluid () and the pressure of the fluid flowing in the flow channel (), i.e. depending on the pressure and the temperature of the fluid flowing in the flow channel (), and thereby the superheat of the fluid. A distance sensor, e.g. comprising a permanent magnet () and a Hall sensor (), measures the distance between the wall parts, and the superheat is calculated from the measured distance. The sensor () is suitable for use in a refrigeration system. The sensor () is mechanically simple and capable of determining the superheat by measuring only one parameter.

Superheat sensor

A method for controlling a refrigerant distribution in a vapour compression system, such as a refrigeration system, e.g. an air condition system, comprising at least two evaporators. The refrigerant distribution determines the distribution of the available amount of refrigerant among the evaporators. While monitoring a superheat, SH, at a common outlet for the evaporators, the distribution of refrigerant is modified in such a manner that a mass flow of refrigerant to a first evaporator is altered in a controlled manner. The impact on the monitored SH is then observed, and this is used for deriving information relating to the behaviour of the first evaporator, in the form of a control parameter. This is repeated for each evaporator, and the refrigerant distribution is adjusted on the basis of the control parameters. The impact may be in the form of a significant change in SH. Alternatively, the control parameter may reflect a change in SH occurring as a result of the modification of the distribution of refrigerant.

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Soenderborg, Denmark

Claus Thybo