Abstract: A method for iteratively estimating a wind speed at a wind turbine is disclosed, said wind turbine comprising a rotor carrying a set of wind turbine blades, each wind turbine blade having a variable pitch angle. A minimum tip speed ratio, ?min, is derived, based on an obtained pitch angle, ?. The minimum tip speed ratio, ?min, defines a limit between a stable and an unstable control region. An initial tip speed ratio, ?init>?min, is selected, and an initial estimated wind speed, vinit, is derived based on the initial tip speed ratio, ?int, and an obtained rotational speed, ?, of the rotor. An estimated wind speed, vest, is iteratively derived, based on the obtained rotational speed, ?, and the obtained pitch angle, ?, and using the derived initial estimated wind speed, vinit, as a starting point. The iterative process converges fast and reliably.

Abstract: A method for controlling a supply of refrigerant to an evaporator (5) of a vapor compression system (1), such as a refrigeration system, an air condition system or a heat pump, is disclosed. The vapor compression system (1) comprises an evaporator (5), a compressor (2), a condenser (3) and an expansion device (4) arranged in a refrigerant circuit. The method comprises the steps of: Actuating a component, such as an expansion valve (4), a fan or a compressor (2), of the vapor compression system (1) in such a manner that a dry zone in the evaporator (5) is changed; measuring a temperature signal representing a temperature of refrigerant leaving the evaporator (5); analyzing the measured temperature signal, e.g.

Abstract: The present invention relates to a method for operating a wind power plant in a wake situation, said wind power plant being connected to a power grid, the method comprising the steps of operating the wind power plant in a predetermined power mode of operation, terminating said predetermined power mode of operation, and increasing power generation of the wind power plant to a power level that exceeds an optimized wake power level of the wind power plant, and injecting the increased amount of power into the power grid as a power boost. Thus, the present invention is capable of generating a power boost to an associated power grid, said power boost exceeding the power level normally being available in a wake situation. The present invention further relates to a system for carrying out the method.

Abstract: A method for determining wire connections in a vapor compression system (1) is disclosed. The vapor compression system comprises a compressor, a condenser, an expansion device (2) and an evaporator (3) being fluidly interconnected in a refrigerant path, and two or more sensor devices (7, 8, 9, 10, 11) arranged for measuring variables which are relevant for the operation of the vapor compression system (1). The method comprises the steps of changing an operational setting, e.g. an opening degree of the expansion device (2) for the vapor compression system (1), monitoring variable values, such as temperatures, being measured by at least two sensor devices (7, 8, 9, 10, 11), e.g.

Abstract: The invention relates to a controller configured to determine one or more future values of blade control references and/or a generator control references for a wind turbine generator. The first of the future values of the control references are used for control purposes. The future control references are determined from a physical model of a system of the wind turbine generator by solving an optimization problem which includes at least one cost function and at least one constraint.

Abstract: 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.

Abstract: The preset invention relates to wind turbines and, in particular inclining a wind turbine from the vertical position. A tower (102) of a wind turbine may be inclined from the vertical position in order to reduce the loads on the tower (102).

Abstract: 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.

Abstract: An expansion device unit (4) for a vapor compression system (1), and a vapor compression system (1) are disclosed. The expansion device unit (4) comprises an inlet opening (17) arranged to receive fluid medium, at least two outlet openings (18) arranged to deliver fluid medium, a main expanding section (6) adapted to expand fluid medium received via the inlet opening (17) before delivering the fluid medium to the outlet openings (18), and a distribution section (7) arranged to split the fluid flow received via the inlet opening (17) into at least two fluid flows to be delivered via the outlet openings (18). The main expanding section (6) and/or the distribution section (7) is/are arranged to cause pressures in fluid delivered via at least two of the outlet openings (18) to be distinct. The main expanding section (6) is operated on the basis of one or more parameters measured in the fluid flow delivered by one of the outlet openings (18).

Abstract: A method for calibrating a superheat sensor (5) for a refrigeration system is provided. The method comprises the following steps. Increasing an amount of liquid refrigerant in the evaporator (1), e.g. by increasing an opening degree of the expansion valve (3). Monitoring one or more parameters, e.g. the temperature of refrigerant leaving the evaporator (1), 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 (5) 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 (1), and thereby that the superheat of the refrigerant leaving the evaporator (1) is zero.

Abstract: A method of analyzing and controlling a refrigeration system (1) including at least one compressor (4), at least one condenser (5) and at least two refrigeration entities (2), each having at least one evaporator (9), includes preventing or reducing evaporator synchronization. Based on information received from the evaporator valve control units by a central control unit (9), it is determined whether or not two or more evaporators (9) are running in a synchronized manner and the refrigeration system (1) is controlled in order to desynchronize the evaporators (9) when two or more evaporators (9) are running in a synchronized manner.

Abstract: The invention provides a method and a system for controlling floor heating or climate regulating systems with long time constants. According to the invention, a flow of a fluid is provided through the floor or through a similar medium with large thermal inertia. An induced heat is determined by adding up a plurality of differences between an inlet temperature of the fluid when it enters the medium and an outlet temperature of the fluid when it leaves the medium. The temperatures are sampled with a fixed sampling time and within a fixed period of time, and a corresponding change in temperature of the medium over the fixed period of time is determined. In the future, the temperature of that medium is controlled by use of a ratio between the induced heat and the change in temperature.

Abstract: The invention provides a method and a system for controlling floor heating or climate regulating systems with long time constants. According to the invention, a flow of a fluid is provided through the floor or through a similar medium with large thermal inertia. An induced heat is determined by adding up a plurality of differences between an inlet temperature of the fluid when it enters the medium and an outlet temperature of the fluid when it leaves the medium. The temperatures are sampled with a fixed sampling time and within a fixed period of time, and a corresponding change in temperature of the medium over the fixed period of time is determined. In the future, the temperature of that medium is controlled by use of a ratio between the induced heat and the change in temperature.

Abstract: A valve assembly (1) comprising an inlet opening, a distributor and an outlet part comprising at least two outlet openings. The distributor comprises an inlet part (5) fluidly connected to the inlet opening, and is arranged to distribute fluid medium received from the inlet opening to at least two parallel flow paths, preferably of a heat exchanger (3). The valve assembly (1) further comprises a first valve part and a second valve part arranged movable relative to each other in such a manner that the mutual position of the valve parts determines the fluid flow from the inlet opening to each of the outlet openings of the outlet part. Finally, the valve assembly (1) comprises a header (2) forming an integral part of the valve assembly (1).

Abstract: A method for controlling a supply of refrigerant to an evaporator (5) of a vapour compression system (1), such as a refrigeration system, an air condition system or a heat pump, is disclosed. The vapour compression system (1) comprises an evaporator (5), a compressor (2), a condenser (3) and an expansion device (4) arranged in a refrigerant circuit. The method comprises the steps of: Actuating a component, such as an expansion valve (4), a fan or a compressor (2), of the vapour compression system (1) in such a manner that a dry zone in the evaporator (5) is changed; measuring a temperature signal representing a temperature of refrigerant leaving the evaporator (5); analysing the measured temperature signal, e.g.

Abstract: An expansion device unit (4) for a vapour compression system (1), and a vapour compression system (1) are disclosed. The expansion device unit (4) comprises an inlet opening (17) arranged to receive fluid medium, at least two outlet openings (18) arranged to deliver fluid medium, a main expanding section (6) adapted to expand fluid medium received via the inlet opening (17) before delivering the fluid medium to the outlet openings (18), and a distribution section (7) arranged to split the fluid flow received via the inlet opening (17) into at least two fluid flows to be delivered via the outlet openings (18). The main expanding section (6) and/or the distribution section (7) is/are arranged to cause pressures in fluid delivered via at least two of the outlet openings (18) to be distinct. The main expanding section (6) is operated on the basis of one or more parameters measured in the fluid flow delivered by one of the outlet openings (18).

Abstract: A method for determining wire connections in a vapour compression system (1) is disclosed. The vapour compression system comprises a compressor, a condenser, an expansion device (2) and an evaporator (3) being fluidly interconnected in a refrigerant path, and two or more sensor devices (7, 8, 9, 10, 11) arranged for measuring variables which are relevant for the operation of the vapour compression system (1). The method comprises the steps of changing an operational setting, e.g. an opening degree of the expansion device (2) for the vapour compression system (1), monitoring variable values, such as temperatures, being measured by at least two sensor devices (7, 8, 9, 10, 11), e.g.

Abstract: The invention provides a method and a system for controlling floor heating or climate regulating systems with long time constants. According to the invention, a flow of a fluid is provided through the floor or through a similar medium with large thermal inertia. An induced heat is determined by adding up a plurality of differences between an inlet temperature of the fluid when it enters the medium and an outlet temperature of the fluid when it leaves the medium. The temperatures are sampled with a fixed sampling time and within a fixed period of time, and a corresponding change in temperature of the medium over the fixed period of time is determined. In the future, the temperature of that medium is controlled by use of a ratio between the induced heat and the change in temperature.

Abstract: The invention provides a method for controlling the climate of an environment, e.g. a house, which exchanges thermal energy with an ambient space. Energy is supplied to the environment e.g. by radiators, floor heating, electrical heating fans etc. According to the method, a numerically expressed comfort criteria, and a numerically expressed weight of importance of compliance with the comfort criterion are defined. Subsequently, a supply of a specific amount of energy is considered, and with respect to that amount, a numerical expression of a degree of compliance with the comfort criterion, and a numerical expression of costs related to the supply of that amount of energy are provided.

Abstract: A method of analysing a refrigeration system (1) comprising at least one compressor (4), at least one condenser (5) and at least two refrigeration entities (2), each comprising at least one evaporator (9). Based on information relating to the gas production by the evaporators (9) it is determined whether or not two or more evaporators (9) are running in a synchronized manner, i.e. are switching between an active and an inactive state at least substantially simultaneously. In case two or more evaporators (9) are running in a synchronized manner, the refrigeration system (1) may be controlled in order to desynchronize the evaporators (9). This may, e.g., be done by changing a cut-in temperature and/or a cut-out temperature for one of the corresponding refrigeration entities (2). Synchronization causes undesired variations in the suction pressure, and preventing synchronization therefore results in a more appropriate control of the refrigeration system (1). Reduces wear on the compressors (4).