RECEIVING AND RELEASING THERMAL ENERGY

Abstract

An arrangement for receiving and/or releasing, in particular storing, thermal energy, including: a container for holding storage material, the container having a first fluid port and a second fluid port for allowing inflow and outflow of fluid flowing through the container in a substantially horizontal flow direction for charging and/or discharging the storage material; at least two first valves at different vertical positions for the first fluid port; at least two second valves at different vertical positions for the second fluid port; and at least two temperature sensors arranged within the container at different vertical positions, in particular in one plane perpendicular to the flow direction.

Claims

1. An arrangement for receiving, and/or releasing, and/or storing, thermal energy, comprising: a container for holding storage material, the container having a first fluid port and a second fluid port for allowing inflow and outflow of fluid flowing through the container in a substantially horizontal flow direction for charging and/or discharging the storage material; at least two first valves at different vertical positions for the first fluid port; at least two second valves at different vertical positions for the second fluid port; at least two temperature sensors arranged within the container at different vertical positions in one plane perpendicular to the flow direction; and a valve controller or a valve controller for each valve, adapted to control at least one of two first valves and/or the two second valves serving as inlet valve based on at least one temperature value measured by at least one of the temperature sensors arranged downstream the at least one inlet valve.

2. The arrangement according to claim 1: wherein the first fluid port is formed by at least two first fluid port members arranged at different vertical positions, the fluid flow through each of the two first fluid port members being controlled by one of the two first valves, and/or wherein the second fluid port is formed by at least two second fluid port members arranged at different vertical positions, the fluid flow through the two second fluid port members being controlled by the two second valves.

3. The arrangement according to claim 1, further comprising: at least two further temperature sensors arranged within the container at different vertical positions and within at least one further plane perpendicular to the flow direction.

4. The arrangement according to claim 1, wherein for each valve of the at least two second valves and the at least two first valves the at least two temperature sensors or at least two outer temperature sensors arranged outside the container comprise: at least one temperature sensor arranged such that a temperature related to a temperature of fluid flowed through the valve is measurable; and wherein the at least one temperature sensor arranged downstream the valve is arranged substantially in a same lateral region as the valve.

5. The arrangement according to claim 1, wherein the at least two first valves comprises at least four first valves distributed in a first plane substantially perpendicular to the flow direction and being spaced apart in two different lateral directions, and/or wherein the at least two second valves comprises at least four second valves distributed in a second plane substantially perpendicular to the flow direction and being spaced apart in two different lateral directions.

6. The arrangement according to claim 1, wherein the first fluid port serves as a fluid inlet during charging and serves as a fluid outlet during discharging: wherein the second fluid port serves as a fluid outlet during charging and serves as a fluid inlet during discharging; wherein the at least two first valves serve as inlet valves during charging and serve as outlet valves during discharging; and wherein the at least two second valves serve as outlet valves during charging and serve as inlet valves during discharging.

7. The arrangement according to claim 1, wherein the valve controller is adapted to control at least one of the two first valves and/or the two second valves serving as outlet valve based on at least one temperature value measured by at least one of the temperature sensors arranged upstream the at least one outlet valve.

8. The arrangement according to claim 1, wherein the valve controller is adapted, during a charging process, to control the inlet valve and/or the outlet valve such as to dynamically: open an inlet valve having lower temperature downstream and/or temperature of the fluid flowed through the valve more than an inlet valve having higher temperature downstream and/or temperature of the fluid flowed through the valve, and/or open an outlet valve having lower temperature upstream and/or temperature of the fluid flowed through the valve more than an outlet valve having higher temperature upstream and/or temperature of the fluid flow through the valve.

9. The arrangement according to claim 1, wherein the valve controller is configured to control at least one of the inlet valves during charging and/or during discharging, including: determining an inlet valve associated actual value of temperature; and determining an inlet valve setting signal based on a deviation between the inlet valve associated actual value of the temperature and an inlet target value of the temperature using a PI or PID controller.

10. The arrangement according to claim 1, wherein to control at least one of the inlet valves includes: determining a plane and/or a location along the flow direction where the temperature reaches a predetermined fraction of a charging related temperature or a discharging related temperature; determining the inlet valve associated actual value of temperature based on at least one temperature as measured by at least one temperature sensor arranged in the determined plane/location in a same/overlapping lateral region as the inlet valve; and determining the inlet target value of the temperature for all inlet valves as a predetermined fraction of, the maximum for charging and the minimum for discharging, of the inlet valve associated actual values of the temperature.

11. The arrangement according to claim 1, wherein the valve controller is configured to control at least one of the outlet valves during charging and/or during discharging, including: determining an outlet valve associated actual value of temperature; and determining an outlet valve setting signal for each of outlet valves based on a deviation between the outlet valve associated actual value of the temperature and an outlet target value of the temperature.

12. The arrangement according to claim 1, wherein to control at least one of the outlet valves includes: determining the outlet valve associated actual value of temperature based on at least one temperature as measured by at least one temperature sensor arranged upstream the outlet valve in a same/overlapping lateral region as the outlet valve; and determining the outlet target value of the temperature for all outlet valves as a predetermined fraction of, the minimum for charging and the maximum for discharging, of the outlet valve associated actual values of the temperature.

13. The arrangement according to claim 1, wherein the valve controller is adapted to determine the outlet valve setting signal and/or the inlet valve setting signal further based on a physical and/or chemical property of the storage material.

14. A method of receiving and/or releasing thermal energy, comprising: allowing, via a first fluid port for which at least two first valves are arranged at different vertical positions and via a second fluid port for which at least two second valves are arranged at different vertical positions, inflow and outflow of fluid flowing through a container holding storage material in a substantially horizontal flow direction for charging and/or discharging the storage material; measuring at least two temperature values within the container at different vertical positions by at least two temperature sensors arranged within the container at different vertical positions and positioned within at least one plane perpendicular to the flow direction; and controlling at least one of two first valves and/or the two second valves serving as inlet valve based on at least one temperature value measured by at least one of the temperature sensors arranged downstream the at least one inlet valve.

Description

BRIEF DESCRIPTION

[0056] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0057] FIG. 1 schematically illustrates an arrangement for receiving and/or releasing thermal energy according to an embodiment of the present invention during a charging process and a discharging process, respectively;

[0058] FIG. 2 schematically illustrates an arrangement for receiving and/or releasing thermal energy according to an embodiment of the present invention during a charging process and a discharging process, respectively;

[0059] FIG. 3 illustrates conventional devices for storing thermal energy;

[0060] FIG. 4 illustrates conventional devices for storing thermal energy;

[0061] FIG. 5 schematically illustrates a perspective view of a portion of an arrangement for receiving and/or releasing thermal energy according to an embodiment of the present invention;

[0062] FIG. 6 schematically illustrates in a sectional view a portion of an arrangement for receiving and/or releasing thermal energy according to an embodiment of the present invention;

[0063] FIG. 7 schematically illustrates in a sectional view an arrangement for receiving and/or releasing thermal energy according to an embodiment of the present invention;

[0064] FIG. 8 schematically illustrates temperature measurement equipment in different planes orthogonal to a flow direction of an arrangement for receiving and/or releasing thermal energy according to an embodiment of the present invention; and

[0065] FIG. 9 schematically illustrates temperature measurement equipment in different planes orthogonal to a flow direction of an arrangement for receiving and/or releasing thermal energy according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0066] The arrangement 100 for receiving and/or releasing, in particular also storing, thermal energy according to an embodiment of the present invention illustrated in FIGS. 1 and 2 during a charging process and a discharging process, respectively, comprises a container 101 for holding storage material 103, wherein the container 101 comprises a first fluid port 105 and a second fluid port 107 for allowing inflow and outflow of fluid 109 flowing through the container 101 in a substantially horizontal flow direction 111 (corresponding to an x-axis direction) for charging and/or discharging the storage material 103. The flow direction 111 corresponds to or is even equal to the horizontal direction. A vertical direction (z-axis direction) is indicated with reference sign 113.

[0067] The arrangement 100 comprises at least two first valves, namely a valve V1b and V1d which are arranged at different vertical positions (as measured along the vertical direction 113). Gravity acts in the vertical direction 113 towards the centre of earth. The arrangement 100 further comprises at least two second valves, V2b, V2d also at different vertical positions which are provided for the second fluid port 107. The arrangement 100 further comprises at least two temperature sensors, for example the temperature sensors T1d and T1b which are arranged within the container 101 at different vertical positions, in particular at vertical positions corresponding to or being substantially equal to the vertical positions of the two first valves V1b and V1d. In particular, the temperature sensors T1b, T1d are arranged in a same plane P1 being perpendicular to the flow direction 111 and which is downstream the two first valves V1b, V1d during the charging process, as is illustrated in FIG. 1. According to other embodiments of the present invention, plural further or other temperature sensors, e.g. T2b, T2d, are arranged within the container 101 and also outside the container 101, such as temperature sensors T1eb arranged within a first fluid port member FP1b and a temperature sensor T1ed arranged within a first fluid port member FP1d.

[0068] Herein, in the embodiment illustrated in FIGS. 1 and 2, the first fluid port 105 is formed by at least two first fluid port members FP1b and FP1d which are arranged at different vertical positions wherein the fluid flow through each of the two first fluid port members FP1b and FP1d are controlled by one of the two first valves V1b and V1d. Also, in the illustrated embodiment, the second fluid port 107 is formed by at least two second fluid port members FP2b and FP2d which are arranged at different vertical positions, wherein the fluid flow through each of the two second fluid port members FP2b, FP2d being controlled by one of the two second valves, V2b, V2d, respectively.

[0069] In the illustrated embodiment, the arrangement 100 comprises at least two further temperature sensors T2b, T2d which are arranged within the container 101 at different vertical positions and within at least one further plane P2 which is spaced apart in the flow direction 111 from the first plane P1 and is perpendicular to the flow direction 111. Also within the second fluid port members FP2b, FP2d respective temperature sensors T2eb and T2ed are arranged so that they are downstream the second valves V2b, V2d during a charging process, as illustrated in FIG. 1.

[0070] As can be appreciated from FIGS. 1 and 2, the first fluid port 105 serves as a fluid inlet during charging and serves as a fluid outlet during discharging, the second fluid port 107 serves as a fluid outlet during charging and serves as a fluid inlet during discharging. Furthermore, the at least two first valves V1b, V1d serve as inlet valves during charging and serve as outlet valves during discharging and the at least two second valves V2b, V2d serve as outlet valves during charging and serve as inlet valves during discharging.

[0071] The arrangement 100 further comprises a valve controller 120 which is adapted to control at least one of two first valves V1b, V1d and/or the two second valves V2b, V2d serving as inlet valves (in particular comprising for each valve a controller portion), based on at least one temperature value 121 measured by at least one of the temperature sensors T1b, T1d, T2b, T2d, T1eb, T1ed, T2eb, T2ed which are arranged downstream the at least inlet valve. The valve controller 120 is further adapted to control one of the afore-mentioned valves which serve as outlet valve. Thereby, the valve controller 120 supplies one or more valve setting signals 123 to the one or more controlled valves.

[0072] During a discharging process, the flow direction 111 of the charging process is reversed to a flow direction 112, as is illustrated in FIG. 2. During discharging, the at least two second valves V2b, V2d serve as inlet valves and the at least two first valves V1b, V1d serve as outlet valves.

[0073] FIGS. 3 and 4 illustrate a conventional heat storage device 300 comprising a container 301 having fluid ports 305, 307 for inflow and outflow of fluid. The conventional storage device does not comprise dynamically controllable valves and does not comprise one or more temperature sensors within the container. Due to gravity during charging as well as during discharging (illustrated in FIG. 4), an inhomogeneous temperature distribution along a vertical direction is present, decreasing the efficiency of the thermal energy storage.

[0074] FIG. 5 schematically illustrates in a perspective view a portion of an arrangement 500 for receiving and/or releasing thermal energy according to an embodiment of the present invention. At a first fluid port 505, four first valves V1a, V1b, V1c, V1d are provided allowing to separately control fluid flow into or out of the container 501. Furthermore, spaced apart in the flow direction 511 the arrangement 500 comprises an array of temperature sensors TXa, TXb, TXc, TXd, wherein the letter “X” refers to a particular plane PX within the container 501 which is perpendicular to the flow direction 511. In particular, the temperature sensor TXa is arranged within a same or similar lateral region as the first valve V1a and is configured to measure temperature of fluid flowed through the first valve V1a, for example during a charging process.

[0075] In particular, the four valves V1a, V1b, V1c, V1d are spaced apart in two lateral directions, for example lateral directions y and z being perpendicular to the flow direction which is in the direction of the x-coordinate. According to other embodiments of the present invention, an arrangement for releasing and/or receiving thermal energy may comprise several arrays of temperature sensors which are arranged at different planes spaced apart in the flow direction 511.

[0076] FIG. 6 schematically illustrates a portion of an arrangement 600 for receiving and/or releasing thermal energy according to an embodiment of the present invention in a sectional view. The arrangement 600 comprises a container 601 comprising storage material 603. For a first fluid port 605 two first valves V1b, V1d are provided which are arranged at different vertical positions along the vertical direction 113 being the z-axis of a coordinate system. The first valves V1b and V1d are controlled regarding the opening or closing state by the valve controller 620 similar as is described with reference to FIGS. 1 and 2.

[0077] In the following, an exemplary embodiment of a method for charging and/or discharging the arrangement 100, 500, 600 is described with reference to FIGS. 7, 8 and 9. In other embodiments, other target temperatures or charging temperatures may be utilized. Furthermore, any averaging methodology may be utilized or applied to derive for example actual temperature value. The weighting of different temperature values determined by different temperature sensors may be according to an effected volume element the respective temperature sensor is associated with.

[0078] The position of each valve is controlled depending on the temperature of the heat transporting fluid and the storage material. When charging the heat storage, the exiting heat flow needs to be as low as possible for a defined total mass flow of the heat transporting fluid. When discharging the heat storage, the exiting heat flow needs to be higher than a defined value as long as possible. The value is defined by the discharging cycle.

[0079] This means that the temperature at the respective outlet needs to be as low as possible when charging and higher than a defined value as long as possible when discharging the heat storage.

[0080] Because there is an uneven distribution of the temperature profile as described above for the conventional system, control parameters need to be calculated. The dynamic valve control can be used to create a more vertical temperature front between the hot storage material and the cold storage material. The up-stream valves at the inlet are preliminary used to control the temperature profile whereas the down-stream valves at the outlet are just used for additional adjusting. Especially during discharge the valves at the inlet redirect the flow from the cold storage material into the hot storage material. If a gap has been formed the valves can redirect the flow from the gap to the storage material.

[0081] To get a better and more reliable temperature profile of the fluid flowing through the storage material, numerous temperature sensors should be used. Therefore, the storage is divided into many temperature planes orthogonal to the flow direction. A temperature is defined to specify the temperature front. For charging it is a lower temperature than charging temperature, calculated by a constant factor smaller than 1. For discharging it is a temperature lower than the minimal possible outlet temperature, calculated by a factor smaller than 1. The control algorithm searches each sensor in each plane for the defined temperature. The algorithm is started at the cold side of the storage and moves further plane by plane. The first plane where the searched temperature occurs is defined as the temperature front plane and will be used to calculate the control parameters.

Example: Charging the Storage

[0082] FIG. 7 schematically illustrates an arrangement 700 for receiving and/or releasing thermal energy according to an embodiment of the present invention including a container 701 containing storage material 703. The fluid enters during a charging process. The first fluid port 705 comprises not in detail illustrated valves at different z-positions. At plural planes P1, P2, . . . Pn temperature sensors T1b, T1d, . . . Tnb, Tnd are present within the container 701. Not illustrated temperature sensors may also be present at different lateral positions along the Y-axis. The temperature sensors may be utilized for determining a temperature front plane as described below.

[0083] The control algorithm at the inlet is as follows: [0084] 1. Calculating the temperature of the temperature front plane with factor x. [0085] 2. searching for the plane the temperature occurs the first time, that Plane is defined as the Temperature frontplane. [0086] 3. Finding the actual process values for each valve [0087] The plane of the temperature front has been found in step 1. The actual process values for each valve are calculated by taking the average temperature of all sensors within the part of the temperature front behind that valve. [0088] FIG. 8 illustrates temperature measurement values as determined by temperature sensors placed within the third plane P3, wherein each of the temperature sensors T3a, T3b, T3c and T3d comprise four independent temperature sensors such that for each of the temperature sensor in fact four temperatures are measured. For each of the temperature sensors T3a, . . . , an associated average temperature is determined. As can be appreciated from FIG. 8, during the charging process, the determined temperature values are higher for the temperature sensors at a higher vertical position z. [0089] 4. Calculate the target value [0090] The target value for each valve for charging/discharging is a defined percentage of the maximum/minimum process value of step 2. This is the target value for all of the valves at the inlet. [0091] 5. Dynamic valve control [0092] Each valve is controlled with a simple PI controller. The target value for each valve has been calculated in step 3 the process value in step 2.

[0093] If the actual process value is greater than the target value the respective valve closes. If the process value is lower than the target value the respective valve opens.

[0094] The dynamic valve control at the outlet should complement the control of the temperature profile. A temperature is calculated as a target value for the dynamic valve control. As soon as the average temperature behind the valve during charging/discharging exceeds/falls below this temperature criterion, the respective valve closes so that only fluid with a temperature equal to or lower/higher than the temperature criterion can exit the heat storage.

[0095] The control algorithm at the outlet is as follows: [0096] 1. Calculate the process value at the outlet the process value for each valve is defined as the average temperature behind that valve. [0097] FIG. 9 illustrates temperature sensors T7a, T7b, T7c, T7d for measuring temperature values in the seventh plane P7 which may be utilized for controlling valves at the outlet. Plane 7 may in fact be located outside the container, for example in a pipe section downstream the respective outlet valve. [0098] 2. Calculate the target value at the outlet [0099] For charging it's a temperature greater than the minimum process value calculated by a factor higher than 1. [0100] For discharging it's a temperature lower than the maximum process value of step 1, calculated by a factor smaller than 1. [0101] 3. Dynamic valve control [0102] Each valve is controlled with a simple PI controller. The target value for each valve has been calculated in step 2, the process value in step 1.

[0103] If the actual process value is higher than the target value, the respective valve closes, if it's bigger than the target value it closes.

[0104] According to an embodiment of the present invention, a dynamic control system controls valves which are positioned at the inlet and the outlet of a heat storage device. The control system may increase the degree of utilization of the heat storage by adjusting the flow and therefore the temperature distribution inside the heat storage. The heat loss resulting from the bypass through a gap which is formed during operation may be reduced as well.

[0105] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0106] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.