Adaptive building control system

Abstract

A building control system (100, fig 1) controls thermal performance of a building (124, fig 1) by controlling position of a retractable blind 102 located at a first position on the building (124, fig 1). A motor 108 moves the blind 102. A light sensor 110 detects light intensity near the retractable blind. A controller 112 controls the position of the retractable blind 102 based on a reference shadow model 120 for the building (124, fig 1) at the first position. The controller 112 determines variation between the detected light intensity and predicted light intensity by the reference shadow model 120 and updates the reference shadow model 120 based on the detected light intensity.

Description

Field The technology relates to the field of building control systems, specifically focusing on thermal performance and energy efficiency in buildings. This involves the management and optimization of solar shading, light intensity, and temperature control within the building environment. Background Large buildings often require effective control of their heating and ventilation systems to maintain a comfortable indoor environment for occupants. One common approach to achieve this is through the use of active cooling systems, such as air conditioning. However, air conditioning systems are known to be energy-intensive and inefficient, leading to increased energy consumption and associated costs. An alternative approach to controlling the thermal performance of a building is through the use of solar shading devices, such as retractable blinds. These devices can prevent the energy from sunlight from entering the building, thereby reducing the heating effect of sunlight and the need for active cooling systems. The position of these retractable blinds can be controlled using a predictive model of the effect of sunlight on the building, based on various parameters such as time of day, building height, climate data, latitude, and facade direction. This predictive model, also known as a shadow model, is specific to a particular building and must be developed once the building has been constructed. The process of developing a shadow model is manually intensive, requiring light measurements to be taken at many different points within the building. Once the shadow model has been implemented and used to control the retractable blinds, it can be difficult to validate its accuracy. This can result in the retractable blinds not providing effective solar shading for the building, leading to suboptimal cooling and energy usage. One prior art, US10585402, relates to a method for building automation that involves generating a reference data structure with setpoint parameters for actuators in a building installation. The method includes determining combinations of measurable sensor values and corresponding setpoint parameter values, and encoding this data into an image format for easier interpretation. The control method involves accessing this reference data structure to select setpoint parameter values based on measured sensor values and applying them to control the actuators accordingly. A problem with the prior art is that the reference data structure, such as the shadow model, is not validated during use. This means that there may be inaccuracies in the reference data structure, leading to suboptimal positioning of the retractable blinds and ineffective solar shading. Additionally, the reference data structure may not take into account long-term changes, such as environmental changes like new buildings being constructed nearby or climate change, which can further impact the accuracy and effectiveness of the solar shading provided by the retractable blinds. Summary According to a first aspect of the disclosure, a building control system is provided for controlling the thermal performance of a building. The system comprises at least one retractable blind located at a first position on the building. The retractable blind is moveable between a retracted position and a deployed or partially deployed position. A motor is operatively connected to the retractable blind for moving the blind between the retracted position and the deployed or partially deployed position. A light sensor is also provided for detecting light intensity near the retractable blind. A controller is included for controlling the position of the retractable blind based on a reference shadow model for the building at the first position. The controller is configured to determine a variation between the detected light intensity at the retractable blind and a predicted light intensity by the reference shadow model and to update the reference shadow model based on the detected light intensity. This aspect of the disclosure allows for efficient control of the thermal performance of a building by adjusting the position of the retractable blind based on real long term light intensity data. Optionally in some examples, the at least one retractable blind is a plurality of retractable blinds located at different positions on the building. This allows for more precise control of the thermal performance of the building as the position of each blind can be individually controlled based on the light intensity detected at its location. Optionally in some examples, the controller is further configured to compare the detected light intensity at the retractable blind with the predicted light intensity of the reference shadow model and to determine a significant difference between the detected light intensity and the predicted light intensity. This feature allows for the continuous updating of the reference shadow model based on real-time data, thereby improving the accuracy of the model. Optionally in some examples, the light sensor is selected from the group consisting of a photodetector, a light-dependent resistor, a photodiode, and a phototransistor. Optionally in some examples, the system further comprises one or more additional sensors selected from the group consisting of an internal temperature sensor, a temperature sensor, and a humidity sensor. These additional sensors provide more data for controlling the thermal performance of the building, thereby improving the efficiency of the system. Optionally in some examples, the controller is located in the retractable blind. This allows for localised control of each blind, thereby improving the responsiveness of the system without the need for a centralised controller. Optionally in some examples, the controller is a centralised controller connected to a plurality of retractable blinds. This allows for centralised control of all the blinds in the building, thereby simplifying the control process. Optionally in some examples, the reference shadow model comprises a look-up table. This allows for quick and easy access to the predicted light intensity data, thereby improving the efficiency of the system. Optionally in some examples, the reference shadow model comprises shadow model parameters including building height, climate data, time of day, time of year, latitude, and facade direction. This allows for a more accurate prediction of light intensity, thereby improving the control of the thermal performance of the building. According to a second aspect of the disclosure, a method of operating a building control system is provided. The method involves detecting light intensity on at least one retractable blind located at a first position on a building. The retractable blind is moveable between a retracted position and a deployed or partially deployed position. The position of the retractable blind is controlled based on a reference shadow model for the building at the first position. The detected light intensity at the retractable blind is compared with the predicted light intensity of the reference shadow model. A variation between the detected light intensity at the retractable blind and the predicted light intensity by the reference shadow model is determined. The reference shadow model is updated based on the detected light intensity. This method allows for efficient control of the thermal performance of a building by adjusting the position of the retractable blind based on real-time light intensity data. Optionally in some examples, the method further comprises comparing the variation between the detected light intensity and the predicted light intensity of the retractable blind at the first position with one or more other retractable blinds located at different positions on the building. This allows for a more comprehensive analysis of the light intensity data, thereby improving the accuracy of the reference shadow model. Optionally in some examples, the step of determining the variation between the detected light intensity and the predicted light intensity by the reference shadow model comprises detecting a statistical variation between the detected light and the reference shadow model. This allows for a more accurate determination of the variation, thereby improving the control of the thermal performance of the building. Optionally in some examples, the step of updating the reference shadow model based on the detected light intensity comprises applying one or more of statistical tools, machine learning algorithms, outlier detection techniques, and time series analysis. This allows for a more sophisticated analysis of the light intensity data, thereby improving the accuracy of the reference shadow model. Optionally in some examples, the method further comprises controlling the position of the retractable blind based on the updated reference shadow model. This allows for real-time adjustment of the position of the blind based on the most recent light intensity data, thereby improving the control of the thermal performance of the building. Optionally in some examples, the step of detecting light intensity on the retractable blind comprises detecting light intensity using a light sensor selected from the group consisting of a photodetector, a light-dependent resistor, a photodiode, and a phototransistor. This provides flexibility in the choice of light sensor, allowing for the selection of the most suitable sensor based on the specific requirements of the building. Brief Description of the Drawings Examples are described in more detail below with reference to the appended drawings. Figure 1 is a schematic representation of a building with a building control system. Figure 2 is a schematic representation of a retractable blind system controlled by a controller with a reference shadow model stored in memory which is updated dynamically during operation of the retractable blind. Figure 3 is a flow diagram of a method of operation of the building control system having one or more retractable blinds which are controlled with a dynamically updated reference shadow model. Detailed Description The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practise the disclosure. Figure 1 shows a schematic representation of a building 124 with a building control system 100. The building control system 100 is designed to control the thermal performance of the building 124. The building 124 includes a window 126 and a plurality of retractable blinds 102 located at different positions on the building 124. The building 124 has many windows 126 and only some are labelled for the purposes of clarity. The retractable blinds 102 are illustrative in that they are able to selectively cover the windows 126. However, in other examples, the retractable blinds 102 can cover any part of the building 124. Figure 1 illustrates a plurality of retractable blinds 102 mounted to the exterior of the building 124. The examples as discussed hereinafter are applicable to one or a plurality of retractable blinds 102 mounted on the building 124. The retractable blinds 102 can be mounted on the exterior of the building 124, but in other examples, alternatively or additionally the retractable blinds 102 mounted on the interior of the building 124 e.g. inside the windows 126. The retractable blinds 102 are moveable between a retracted position and a deployed or partially deployed position. Each retractable blind 102 includes a motor 108 operatively connected to the retractable blind 102 for moving the retractable blind 102 between the retracted position and the deployed or partially deployed position. A light sensor 110 is provided for detecting light intensity near the retractable blind 102. Figure 2 shows a schematic representation of a retractable blind 102 controlled by a controller 112 with a reference shadow model 120 stored in memory 114 which is updated dynamically during operation of the retractable blind 102. The controller 112 is configured to control the position of the retractable blind 102 based on the reference shadow model 120 for the building 124 at the first position. The controller 112 is also configured to determine a variation between the detected light intensity at the retractable blind 102 and a predicted light intensity by the reference shadow model 120 and to update the reference shadow model 120 based on the detected light intensity. The retractable blind control module 122 is responsible for controlling the position of the retractable blind 102 based on the reference shadow model 120. Figure 3 shows a flow diagram of a method of operation of the building control system 100 having one or more retractable blinds 102 which are controlled with a dynamically updated reference shadow model 120. The method includes detecting light intensity on the retractable blind 102, controlling the position of the retractable blind 102 based on the reference shadow model 120, comparing the detected light intensity at the retractable blind 102 with the predicted light intensity of the reference shadow model 120, determining a variation between the detected light intensity at the retractable blind 102 and the predicted light intensity by the reference shadow model 120, and updating the reference shadow model 120 based on the detected light intensity. 1. Component Details The disclosed technology includes various components that work together to form a building control system 100. These components are designed to control the thermal performance of a building 124 by adjusting the position of retractable blinds 102 based on real-time sensor data and a reference shadow model 120. The components of the building control system 100 include a retractable blind 102, a fabric 104, a fabric barrel 106, a motor 108, and a light sensor 110, among others. Each of these components plays a role in the operation of the building control system 100 and contributes to its overall functionality and efficiency. 1.1. Building Control System The building control system 100 is a comprehensive system designed to control the thermal performance of a building 124. The building control system 100 includes at least one retractable blind assembly having a retractable blind 102, a motor 108, a light sensor 110, and a controller 112. Whilst reference is made to a single retractable blind 102, the examples are applicable to an array of a plurality of retractable blinds 102. Such an array of retractable blinds 102 work together to control the thermal performance of the building 124. The controller 112 is responsible for controlling the position of the retractable blind 102 based on a reference shadow model 120. The reference shadow model 120 predicts the light intensity at a position on the building 124 based on one or more building parameters as discussed in more detail below. The controller 112 is configured to determine a variation between the detected light intensity at the retractable blind 102 and a predicted light intensity by the reference shadow model 120 and to update the reference shadow model 120 based on the detected light intensity. 1.1.1. Retractable Blind The retractable blind 102 is a component of the building control system 100. The retractable blind 102 is located at a first position on a building 124 and is moveable between a retracted position and a deployed or partially deployed position. Other retractable blinds 102 are mounted at different positions on the building 124. For example a second retractable blind 102 is mounted at a second position on the building 124. The first position and the second position are different positions on the building 124 and may experience different light intensities. As such the first position and the second position of the different retractable blinds 102 has different reference shadow models 120. In this way, each separate retractable blind 102 may have a different reference shadow model 120 corresponding to the different location of the retractable blind 102. The retractable blind 102 includes a fabric 104 mounted on a fabric barrel 106. The position of the retractable blind 102 is controlled by a motor 108 that is operatively connected to the fabric barrel 106. The retractable blind 102 also includes a light sensor 110 for detecting light intensity near the blind. 1.1.1.1. Fabric The fabric 104 of the retractable blind 102 is mounted on the fabric barrel 106. The fabric 104 is designed to be moveable between a retracted position and a deployed or partially deployed position. In some implementations, the fabric 104 may be made of a material that is capable of blocking or filtering sunlight to control the amount of light entering the building 124. The fabric 104 may be available in various colours, patterns, and materials to suit the aesthetic preferences of the building owner or occupants. The fabric 104 is rollable on the fabric barrel 106. In some examples, the fabric 104 can be a polyester fabric, a polypropylene fabric, a nylon fabric, or a cotton fabric or any other suitable fabric 104 or rollable material. 1.1.1.2. Fabric Barrel The fabric barrel 106 is a component of the retractable blind 102 on which the fabric 104 is mounted. The fabric barrel 106 is designed to allow the fabric 104 to be wound or unwound, thereby enabling the retractable blind 102 to move between a retracted position and a deployed or partially deployed position. The fabric barrel 106 is operatively connected to the motor 108, which controls the movement of the fabric 104. 1.1.1.3. Motor The motor 108 is a component of the retractable blind 102. The motor 108 is operatively connected to the fabric barrel 106 and is responsible for moving the fabric 104 between the retracted position and the deployed or partially deployed position. The motor 108 may be an electric motor 108 powered by a power source such as a battery or a power grid. The motor 108 may be controlled by the controller 112 based on the reference shadow model 120 and the detected light intensity. 1.1.1.4. Light Sensor The light sensor 110 is a component of the retractable blind 102 that is responsible for detecting light intensity near the retractable blind 102. In some examples, the light sensor 110 is configured to determine the light intensity for the location of the retractable blind 102. In this way each retractable blind 102 may detect specific light intensity information associated with the specific location of the retractable blind 102. In some other examples, the light sensor 110 is configured to determine the light intensity for the location of the retractable blind 102 and a surrounding area to the retractable blind 102. In this way the light sensor 110 can detect the light intensity for a plurality of nearby retractable blinds 102. For example, a light sensor 110 may be configured to detect the light intensity for a group of four retractable blinds 102. The light sensor 110 can detect the light intensity for any suitable number of neighbouring retractable blinds 102. The groups of retractable blinds 102 may be clustered based on similarities e.g. location, fagade direction, height etc. The light sensor 110 may be a photodetector, a light-dependent resistor (LDR), a photodiode, or a phototransistor. The light sensor 110 provides real-time data on the light intensity near the retractable blind 102 to the controller 112. This data is used by the controller 112 to determine a variation between the detected light intensity and a predicted light intensity by the reference shadow model 120, and to update the reference shadow model 120 based on the detected light intensity. 1.1.1.5. Other Sensors In addition to the light sensor 110, the retractable blind 102 may also include other sensors that provide additional data to the controller 112. These other sensors may include an internal temperature sensor, a temperature sensor, and a humidity sensor. These sensors provide data on the internal temperature, external temperature, and humidity near the retractable blind 102, respectively. This data can be used by the controller 112 to further refine the control of the position of the retractable blind 102 based on the reference shadow model 120. 1.1.1.5.1. Internal Temperature Sensor The internal temperature sensor is a component of the retractable blind 102 that is responsible for detecting the temperature inside the building 124. The internal temperature sensor provides real-time data on the internal temperature to the controller 112. This data can be used by the controller 112 to determine if the current position of the retractable blind 102 is providing the desired thermal performance. If the internal temperature is too high or too low, the controller 112 can adjust the position of the retractable blind 102 to increase or decrease the amount of sunlight entering the building 124, thereby adjusting the internal temperature. 1.1.1.5.2. Temperature Sensor The temperature sensor is another component of the retractable blind 102 that is responsible for detecting the temperature outside the building 124. The temperature sensor provides real-time data on the external temperature to the controller 112. This data can be used by the controller 112 in conjunction with the data from the internal temperature sensor to determine the optimal position of the retractable blind 102. For example, if the external temperature is high and the internal temperature is also high, the controller 112 may decide to move the retractable blind 102 to a more deployed position to block more sunlight and reduce the internal temperature. 1.1.1.5.3. Humidity Sensor The humidity sensor is a component of the retractable blind 102 that is responsible for detecting the humidity near the blind. The humidity sensor provides real-time data on the humidity to the controller 112. This data can be used by the controller 112 to determine if the current position of the retractable blind 102 is providing the desired thermal performance. For example, if the humidity is high and the internal temperature is also high, the controller 112 may decide to move the retractable blind 102 to a more deployed position to block more sunlight and reduce the internal temperature. 1.1.2. Controller The controller 112 controls the position of the retractable blind 102 based on the reference shadow model 120. The controller 112 is configured to determine a variation between the detected light intensity at the retractable blind 102 and a predicted light intensity by the reference shadow model 120 and to update the reference shadow model 120 based on the detected light intensity. The controller 112 includes a retractable blind control module 122, a memory 114, and a comparison module 116. 1.1.2.1. Retractable Blind Control Module The retractable blind control module 122 is a component of the controller 112 that is responsible for controlling the position of the retractable blind 102 based on the reference shadow model 120. Depending on the time of day, the time of year the retractable blind control module 122 issues control instructions to the retractable blind 102 to be adjusted to a specific position as defined in the reference shadow model 120 for the position of the retractable blind 102. The retractable blind control module 122 may control one retractable blind 102 or a plurality of retractable blinds in order to deflect light on the building 124 to achieve a desired thermal performance. The retractable blind control module 122 sends commands to the motor 108 to move the retractable blind 102 to the determined position. 1.1.2.2. Memory The memory 114 is a component of the controller 112 that is responsible for storing the reference shadow model 120. The memory 114 may be a non-volatile memory 114 that retains the stored data even when the building control system 100 is powered off. The memory 114 allows the controller 112 to access the reference shadow model 120 quickly and efficiently, enabling the controller 112 to make real-time decisions about the position of the retractable blind 102 based on the detected light intensity and the reference shadow model 120. 1.1.2.3. Comparison Module The comparison module 116 is a component of the controller 112 that is responsible for determining a variation between the detected light intensity at the retractable blind 102 and a predicted light intensity by the reference shadow model 120. The predicted light intensity will depend on the location of the retractable blind 102 and other parameters such as time of day, time of year etc. The comparison module 116 receives data from the light sensor 110 and the memory 114, and uses this data to calculate the variation. If the variation is determined to be significant, the comparison module 116 signals the controller 112 to update the reference shadow model 120 based on the detected light intensity. The significance of a variation can be based on a threshold variance (e.g. 5% -10% difference) or other statistical methods as discussed below. 1.1.2.4. Update Module The update module 118 is a component of the controller 112 that is responsible for updating the reference shadow model 120 based on the detected light intensity. The update module 118 receives data from the comparison module 116 indicating a significant variation between the detected light intensity and the predicted light intensity by the reference shadow model 120. In response to this data, the update module 118 updates the reference shadow model 120 based on the detected variation. For example, in some examples, the reference shadow module 120 can be updated to reflect the detected light intensity. Alternatively, reference shadow module 120 can be updated to reflect a time averaged light intensity at the location of the retractable blind 102. This updated reference shadow model 120 is then used by the controller 112 to control the position of the retractable blind 102 thereafter. 1.1.3. Reference Shadow Model The reference shadow model 120 is a predictive model used by the controller 112 to predict the light intensity at a position on the building 124 based on one or more building parameters. The reference shadow model 120 is stored in the memory 114 of the controller 112 and is updated by the update module 118 based on the detected light intensity. The reference shadow model 120 includes a look-up table and various shadow model parameters such as building height, climate data, time of day, time of year, latitude, and facade direction. 1.1.3.1. Look Up Table The look-up table is a component of the reference shadow model 120 that provides a quick and efficient way for the controller 112 to predict the light intensity at a position on the building 124. The look-up table includes a set of pre-calculated values that represent the predicted light intensity for various combinations of building parameters. Furthermore, the look up table indicates a required retractable blind fabric position (e.g. deployed, partially deployed or fully retracted) based on the predicted light intensity and required solar shading of the building 124 to provide a required thermal performance of the building 124. The controller 112 can use the look-up table to quickly determine the predicted light intensity and the retractable blind fabric position without having to perform complex calculations. 1.1.3.2. Shadow Model Parameters The shadow model parameters are a set of parameters that are used by the reference shadow model 120 to predict the light intensity at a position on the building 124. These parameters may include the building height, climate data, time of day, time of year, latitude, and facade direction. Other parameters can be used to refine and determine the reference shadow model 120. Each of these parameters can affect the amount of sunlight that reaches a position on the building 124, and therefore can affect the light intensity at that position. 1.1.3.2.1. Building Height The building height is one of the shadow model parameters used by the reference shadow model 120. The height of the building 124 can affect the angle at which sunlight reaches the building 124, and therefore can affect the light intensity at a position on the building 124. For example, a taller building may receive more sunlight than a shorter building which is occluded by taller surrounding buildings, resulting in a higher light intensity at a high retractable blind 102 position on the taller building. 1.1.3.2.2. Climate Data The climate data is another one of the shadow model parameters used by the reference shadow model 120. The climate data may include information about the average temperature, humidity, and cloud cover for the location of the building 124. This data can affect the amount of sunlight that reaches the building 124, and therefore can affect the light intensity at a position on the building 124. For example, a location with a high average cloud cover may receive less sunlight than a location with a low average cloud cover, resulting in a lower light intensity at a position on the building in the location with the high average cloud cover. 1.1.3.2.3. Time Of Day The time of day is another one of the shadow model parameters used by the reference shadow model 120. The time of day can affect the angle and intensity of sunlight that reaches the building 124, and therefore can affect the light intensity at a position on the building 124. For example, the light intensity at a position on the building 124 is likely to be higher at noon when the sun is at its highest point in the sky, compared to early morning or late afternoon when the sun is lower in the sky. 1.1.3.2.4. Time Of Year The time of year is another one of the shadow model parameters used by the reference shadow model 120. The time of year can affect the angle and intensity of sunlight that reaches the building 124, and therefore can affect the light intensity at a position on the building 124. For example, the light intensity at a position on the building 124 is likely to be higher in the summer when the sun is higher in the sky and the days are longer, compared to the winter when the sun is lower in the sky and the days are shorter. 1.1.3.2.5. Latitude The latitude is another one of the shadow model parameters used by the reference shadow model 120. The latitude of the building's location can affect the angle and intensity of sunlight that reaches the building 124, and therefore can affect the light intensity at a position on the building 124. For example, buildings 124 located closer to the equator may receive more intense sunlight than buildings 124 located closer to the poles, resulting in a higher light intensity at a position on the buildings 124 closer to the equator. 1.1.3.2.6. Facade Direction The facade direction is another one of the shadow model parameters used by the reference shadow model 120. The direction that a facade of the building faces can affect the amount of sunlight that reaches that facade, and therefore can affect the light intensity at a position on that facade. For example, a facade that faces south in the northern hemisphere may receive more sunlight than a facade that faces north in the northern hemisphere, resulting in a higher light intensity at a position on the southfacing facade. 1.2. Building The building 124 is the structure in which the building control system 100 is installed. The building 124 may be a residential, commercial, industrial, or public building 124. The building 124 includes a window 126 and a plurality of retractable blinds 102 located at different positions on the building 124. The retractable blinds 102 are designed to control the amount of sunlight that enters the building through the window 126, thereby controlling the thermal performance of the building 124. 1.2.1. Window The window 126 is a component of the building 124 through which sunlight enters the building 124. The window 126 may be made of glass or another transparent or semitransparent material. The window 126 may be covered by the retractable blind 102 to control the amount of sunlight that enters the building 124. The position of the retractable blind 102 over the window 126 is controlled by the building control system 100 based on the reference shadow model 120 and the detected light intensity. 2. Method Details The method details section describes the operational process of the building control system 100. This process includes detecting light intensity on the retractable blind 102, controlling the position of the retractable blind 102 based on the reference shadow model 120, comparing the detected light intensity at the retractable blind 102 with the predicted light intensity of the reference shadow model 120, determining a variation between the detected light intensity at the retractable blind 102 and the predicted light intensity by the reference shadow model 120, and updating the reference shadow model 120 based on the detected light intensity. This process allows the building control system 100 to dynamically adjust the position of the retractable blind 102 to optimise the thermal performance of the building 124. 2.1. Light Intensity Detection The first step in the operational process of the building control system 100 is the detection of light intensity on the retractable blind 102. This is accomplished using the light sensor 110, which is designed to detect the intensity of light near the retractable blind 102. The light sensor 110 provides real-time data on the light intensity, which is used by the controller 112 to validate the position of the retractable blind 102 as indicated in the reference shadow model 120. 2.1.1. Sensor Types and Placement The light sensor 110 may be of various types, including a photodetector, a lightdependent resistor (LDR), a photodiode, or a phototransistor. Each of these types of light sensors 110 has its own characteristics and advantages, and the choice of sensor type may depend on various factors such as the specific requirements of the building control system 100, the environmental conditions at the location of the building 124, and the cost and availability of the sensors. The placement of the light sensor 110 is also relevant, as it should be located in a position where it can accurately detect the light intensity near the retractable blind 102. In some examples, the light sensor 110 is integrated into the retractable blind 102. Furthermore, the light sensor 110 may be integrated together with the controller 112 on the same circuit board in the retractable blind 102. In some examples, the light sensor 110 is integrated into a hembar or any other component of the retractable blind 102. 2.2. Reference Shadow Model Comparison Once the light intensity has been detected by the light sensor 110, the next step in the operational process of the building control system 100 is to compare the detected light intensity with the predicted light intensity of the reference shadow model 120. This comparison is performed by the comparison module 116 of the controller 112. The comparison module 116 determines a variation between the detected light intensity and the predicted light intensity by the reference shadow model 120. The comparison between the detected light intensity and the predicted light intensity in the reference shadow model 120 may be made based on time averaged data. This may be preferable so that temporary variations in light intensity can be ignored. The time average data may be over a predetermined time e.g. a period of hours, days, or, weeks etc. Furthermore, the time averaged data may be over several years, but only considering the same day in consecutive years is analysed. Indeed any suitable data collection technique can be contemplated in order to ignore short term temporary fluctuations in light intensity. 2.2.1. Variation Determination The determination of the variation between the detected light intensity and the predicted light intensity by the reference shadow model 120 is a step in the operational process of the building control system 100. The controller 112 may detect a variation but only update the reference shadow model 120 if the variation is considered statistically significant. If the variation is significant, it indicates that the current position of the retractable blind 102 is not providing the desired thermal performance, and the controller 112 may need to adjust the position of the retractable blind 102. The determination of the variation may involve various statistical techniques, such as calculating the difference between the detected and predicted light intensities, calculating the percentage difference, or calculating a statistical measure of the variation such as the standard deviation or the variance. 2.2.2. Statistical Analysis Techniques Various statistical analysis techniques may be used to determine the variation between the detected light intensity and the predicted light intensity by the reference shadow model 120. These techniques may include standard statistical methods such as calculating the mean, median, mode, range, variance, standard deviation, or coefficient of variation. In some implementations, more advanced statistical techniques may be used, such as regression analysis, correlation analysis, or principal component analysis. These techniques can provide a more detailed and accurate assessment of the variation, and can help the controller 112 to make more informed decisions about the position of the retractable blind 102. 2.3. Model Update Process If the comparison module 116 determines that there is a significant variation between the detected light intensity and the predicted light intensity by the reference shadow model 120, the next step in the operational process of the building control system 100 is to update the reference shadow model 120 based on the detected light intensity. This update process is performed by the update module 118 of the controller 112. 2.3.1. Use of Detected Light Intensity The detected light intensity is used by the update module 118 to update the reference shadow model 120. The update process may involve adjusting the parameters of the reference shadow model 120 to better match the detected light intensity. For example, if the detected light intensity is consistently higher than the predicted light intensity, the update module 118 may adjust the reference shadow model 120 to predict a higher light intensity. Conversely, if the detected light intensity is consistently lower than the predicted light intensity, the update module 118 may adjust the reference shadow model 120 to predict a lower light intensity. The updated reference shadow model 120 is then used by the controller 112 to control the position of the retractable blind 102. 2.4. Blind Position Control The final step in the operational process of the building control system 100 is to control the position of the retractable blind 102 based on the updated reference shadow model 120. This is accomplished by the retractable blind control module 122 of the controller 112, which sends commands to the motor 108 to move the retractable blind 102 to the determined position. The position of the retractable blind 102 is adjusted to optimise the thermal performance of the building 124, based on the detected light intensity and the updated reference shadow model 120. 2.4.1. Based on Updated Shadow Model The position of the retractable blind 102 is controlled based on the updated reference shadow model 120. The updated reference shadow model 120 provides a more accurate prediction of the light intensity at the position of the retractable blind 102, taking into account the detected light intensity and the various shadow model parameters. The retractable blind control module 122 uses the updated reference shadow model 120 to determine the optimal position of the retractable blind 102. This position is then communicated to the motor 108, which adjusts the position of the retractable blind 102 accordingly. 3. Operational Process The operational process of the building control system 100 involves a series of steps that are performed in a specific order to control the thermal performance of the building 124. These steps include the initial setup and calibration of the system, the real-time operation of the system, and the continuous update and control of the system based on the detected light intensity and the reference shadow model 120. 3.1. Initial Setup and Calibration The initial setup and calibration of the building control system 100 involves the installation of the retractable blind 102 and the various sensors, and the calibration of these components to ensure accurate and reliable operation. The initial setup and calibration process is for the proper operation of the building control system 100, as it ensures that the system is correctly configured to control the thermal performance of the building 124. 3.1.1. Blind and Sensor Installation The installation of the retractable blind 102 and the various sensors is a part of the initial setup and calibration process. The retractable blind 102 is installed at a first position on the building 124, and the fabric 104 is mounted on the fabric barrel 106. The motor 108 is operatively connected to the fabric barrel 106 to control the movement of the fabric 104. The light sensor 110 is installed near the retractable blind 102 to detect the light intensity. Other sensors, such as the internal temperature sensor, the temperature sensor, and the humidity sensor, are also installed at appropriate locations to provide additional data to the controller 112. 3.2. Real-Time Operation Once the initial setup and calibration process is complete, the building control system 100 enters the real-time operation phase. During this phase, the system continuously monitors the light intensity near the retractable blind 102, controls the position of the retractable blind 102 based on the reference shadow model 120, compares the detected light intensity with the predicted light intensity of the reference shadow model 120, determines a variation between the detected and predicted light intensities, and updates the reference shadow model 120 based on the detected light intensity. 3.2.1. Light Detection and Analysis The real-time operation phase begins with the detection of light intensity near the retractable blind 102 by the light sensor 110. The light sensor 110 provides real-time data on the light intensity, which is sent to the controller 112. The controller 112 analyses this data to determine the current light conditions near the retractable blind 102. 3.2.2. Blind Position Adjustment Based on the detected light intensity and the reference shadow model 120, the controller 112 determines the optimal position of the retractable blind 102. The controller 112 sends commands to the motor 108 to move the retractable blind 102 to the determined position. This adjustment of the position of the retractable blind 102 allows the building control system 100 to control the amount of sunlight that enters the building 124, thereby controlling the thermal performance of the building 124. 3.3. Continuous Update and Control The building control system 100 operates continuously, constantly updating and controlling the position of the retractable blind 102 based on the detected light intensity and the reference shadow model 120. This continuous operation allows the system to dynamically adjust to changes in the light conditions and to maintain optimal thermal performance of the building 124. 3.3.1. Shadow Model Update One of the aspects of the continuous operation of the building control system 100 is the updating of the reference shadow model 120. The update module 118 of the controller 112 is responsible for this process. The update module 118 receives data from the comparison module 116 indicating a significant variation between the detected light intensity and the predicted light intensity by the reference shadow model 120. In response to this data, the update module 118 updates the reference shadow model 120 based on the detected light intensity. This updated reference shadow model 120 is then used by the controller 112 to control the position of the retractable blind 102. 3.3.2. Response to Significant Variations The building control system 100 is designed to respond to significant variations between the detected light intensity and the predicted light intensity by the reference shadow model 120. If such a variation is detected, the controller 112 adjusts the position of the retractable blind 102 to optimise the thermal performance of the building 124. This adjustment may involve moving the retractable blind 102 to a more retracted position if the detected light intensity is higher than the predicted light intensity, or to a more deployed position if the detected light intensity is lower than the predicted light intensity. 4. Description of Examples of the Disclosure The following examples provide further illustration of the disclosed technology and its operation. 4.1. Single Blind System In one example, the building control system 100 includes a single retractable blind 102. The retractable blind 102 is located at a first position on a building 124 and is moveable between a retracted position and a deployed or partially deployed position. The position of the retractable blind 102 is controlled by a motor 108 that is operatively connected to the fabric barrel 106. A light sensor 110 is provided for detecting light intensity near the retractable blind 102. The controller 112 controls the position of the retractable blind 102 based on a reference shadow model 120 for the building 124 at the first position. 4.1.1. Operation and Control The operation and control of the single blind system involve detecting light intensity on the retractable blind 102, controlling the position of the retractable blind 102 based on the reference shadow model 120, comparing the detected light intensity at the retractable blind 102 with the predicted light intensity of the reference shadow model 120, determining a variation between the detected light intensity at the retractable blind 102 and the predicted light intensity by the reference shadow model 120, and updating the reference shadow model 120 based on the detected light intensity. 4.2. Multiple Blind System In some implementations, the building control system 100 includes a plurality of retractable blinds 102 located at different positions on the building 124. Each retractable blind 102 is moveable between a retracted position and a deployed or partially deployed position, and each has its own motor 108 and light sensor 110. The controller 112 is a centralised controller 112 connected to all of the retractable blinds 102, and controls the position of each retractable blind 102 based on a reference shadow model 120 for the building 124 at the respective position of each blind. In this multiple blind system, the controller 112 can control the position of each retractable blind 102 independently, allowing for more precise control of the thermal performance of the building 124. For example, if the light intensity at one position on the building 124 is higher than at another position, the controller 112 can move the retractable blind 102 at the first position to a more deployed position to block more sunlight, while leaving the retractable blind 102 at the second position in a more retracted position to allow more sunlight to enter. This independent control of each retractable blind 102 allows the building control system 100 to optimise the thermal performance of the building 124 based on the specific light conditions at each position on the building 124. 4.2.1. Centralised vs Decentralised Control In the multiple blind system, the controller 112 can be either centralised or decentralised. In a centralised control system, a single controller 112 is connected to all of the retractable blinds 102 and controls the position of each blind based on the reference shadow model 120 for the building 124 at the respective position of each blind. This centralised control system allows for coordinated control of all of the blinds, which can be beneficial in situations where the light conditions are similar across the entire building 124. In a decentralised control system, each retractable blind 102 has its own controller 112, and each controller 112 controls the position of its respective blind independently based on the reference shadow model 120 for the building 124 at the position of that blind. This decentralised control system allows for more precise control of each blind, which can be beneficial in situations where the light conditions vary significantly across different positions on the building 124. 4.3. Use of Different Sensor Types The building control system 100 can use different types of sensors to detect the light intensity near the retractable blind 102. These sensor types may include a photodetector, a light-dependent resistor (LDR), a photodiode, or a phototransistor. Each of these sensor types has its own characteristics and advantages, and the choice of sensor type may depend on various factors such as the specific requirements of the building control system 100, the environmental conditions at the location of the building 124, and the cost and availability of the sensors. 4.3.1. Photodetector, LDR, Photodiode, Phototransistor A photodetector is a type of sensor that converts light into an electrical signal. Photodetectors are widely used in various applications due to their high sensitivity and fast response time. A light-dependent resistor (LDR) is a type of sensor that changes its resistance based on the amount of light it receives. LDRs are simple and inexpensive, making them a popular choice for light detection applications. A photodiode is a type of sensor that converts light into current or voltage. Photodiodes are known fortheir high speed and sensitivity, making them suitable for high-precision light detection applications. A phototransistor is a type of sensor that uses light to control the flow of current. Phototransistors are highly sensitive and can detect very small changes in light intensity, making them ideal for applications that require precise light detection. 5. Potential Applications The building control system 100 has potential applications in various types of buildings, including residential buildings, commercial buildings, industrial buildings, and public buildings. The system can be used to control the thermal performance of these buildings by adjusting the position of retractable blinds 102 based on real-time sensor data and a reference shadow model 120. 5.1. Residential Buildings In residential buildings, the building control system 100 can be used to control the amount of sunlight that enters the building, thereby controlling the temperature and lighting conditions inside the building. This can improve the comfort of the occupants and can reduce the need for artificial lighting and air conditioning, leading to energy savings. 5.1.1. Energy Efficiency and Comfort The building control system 100 can improve the energy efficiency of residential buildings by reducing the need for artificial lighting and air conditioning. By controlling the position of the retractable blinds based on the detected light intensity and the reference shadow model 120, the system can optimise the amount of sunlight that enters the building, thereby providing natural lighting and reducing the need for artificial lighting. Similarly, by blocking excessive sunlight, the system can reduce the heat gain inside the building, thereby reducing the need for air conditioning. At the same time, the system can improve the comfort of the occupants by maintaining optimal lighting and temperature conditions inside the building 124. 5.2. Commercial Buildings In commercial buildings, the building control system 100 can be used to control the thermal performance of the building, leading to cost savings and improved working conditions. The system can control the amount of sunlight that enters the building, thereby controlling the temperature and lighting conditions inside the building. This can reduce the need for artificial lighting and air conditioning, leading to energy savings and cost savings. At the same time, the system can improve the working conditions by maintaining optimal lighting and temperature conditions inside the building 124. 5.2.1. Cost Savings and Environmental Impact The building control system 100 can lead to significant cost savings in commercial buildings by reducing the energy consumption for artificial lighting and air conditioning. By optimising the amount of sunlight that enters the building, the system can reduce the need for artificial lighting, thereby saving on electricity costs. Similarly, by blocking excessive sunlight, the system can reduce the heat gain inside the building, thereby reducing the need for air conditioning and saving on energy costs. In addition to cost savings, the reduction in energy consumption can also reduce the environmental impact of the building, contributing to sustainability efforts. 5.3. Industrial Buildings In industrial buildings, the building control system 100 can be used to control the thermal performance of the building, leading to improved process control and safety. The system can control the amount of sunlight that enters the building, thereby controlling the temperature and lighting conditions inside the building. This can be particularly in industrial processes that are sensitive to temperature and light conditions. At the same time, the system can improve safety by maintaining optimal lighting conditions inside the building 124. 5.3.1. Process Control and Safety The building control system 100 can improve process control in industrial buildings by maintaining optimal temperature and lighting conditions. Certain industrial processes may be sensitive to temperature and light conditions, and the system can help to maintain these conditions within the required ranges by controlling the amount of sunlight that enters the building. This can lead to improved process control and product quality. In addition, the system can improve safety in industrial buildings by maintaining optimal lighting conditions, making it easier for workers to see and reducing the risk of accidents. 5.4. Public Buildings In public buildings, such as schools, hospitals, and government buildings, the building control system 100 can be used to control the thermal performance of the building, leading to improved comfort for occupants and energy management. The system can control the amount of sunlight that enters the building, thereby controlling the temperature and lighting conditions inside the building. This can improve the comfort of the occupants and can reduce the need for artificial lighting and air conditioning, leading to energy savings. 5.4.1. Energy Management and Sustainability The building control system 100 can improve energy management in public buildings by reducing the energy consumption for artificial lighting and air conditioning. By controlling the amount of sunlight that enters the building, the system can reduce the need for artificial lighting, thereby saving on electricity costs. Similarly, by blocking excessive sunlight, the system can reduce the heat gain inside the building, thereby reducing the need for air conditioning and saving on energy costs. In addition to improving energy management, the reduction in energy consumption can also contribute to sustainability efforts, helping public buildings to reduce their environmental impact. The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof. It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure. Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealised or overly formal sense unless expressly so defined herein. It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

Claims

1. A building control system (100) for controlling the thermal performance of a building (124), the system comprising:at least one retractable blind (102) located at a first position on the building (124), the retractable blind (102) being moveable between a retracted position and a deployed or partially deployed position;a motor (108) operatively connected to the retractable blind (102) for moving the retractable blind (102) between the retracted position and the deployed or partially deployed position;and a light sensor (110) for detecting light intensity near the retractable blind (102); anda controller (112) for controlling the position of the retractable blind (102) based on a reference shadow model (120) for the building (124) at the first position, the controller (112) being configured to determine a variation between the detected light intensity at the retractable blind (102) and a predicted light intensity by the reference shadow model (120) and to update the reference shadow model (120) based on the detected light intensity.

2. A building control system (100) according to claim 1 wherein the at least one retractable blind (102) is a plurality of retractable blinds (102) located at different positions on the building (124).

3. A building control system (100) according to claim 1 or 2, wherein the controller (112) is further configured to compare the detected light intensity at the retractable blind (102) with the predicted light intensity of the reference shadow model (120) and to determine a significant difference between the detected light intensity and the predicted light intensity.

4. A building control system (100) according to any one of claims 1 to 3, wherein the light sensor (110) is selected from the group consisting of a photodetector, a lightdependent resistor (LDR), a photodiode, and a phototransistor.

5. A building control system (100) according to any one of claims 1 to 4, further comprising one or more additional sensors selected from the group consisting of an internal temperature sensor, a temperature sensor, and a humidity sensor.

6. A building control system (100) according to any one of claims 1 to 5, wherein the controller (112) and the light sensor (110) are located in the retractable blind (102).

7. A building control system (100) according to any one of claims 1 to 6, wherein the controller (112) is a centralised controller connected to a plurality of retractable blinds (102).

8. A building control system (100) according to any one of claims 1 to 7, wherein the reference shadow model (120) comprises a look-up table.

9. A building control system (100) according to any one of claims 1 to 8, wherein the reference shadow model (120) comprises shadow model parameters including building height, climate data, time of day, time of year, latitude, and facade direction.

10. A method of operating a building control system (100) comprising:detecting light intensity on at least one retractable blind (102) located at a first position on a building (124), the retractable blind (102) being moveable between a retracted position and a deployed or partially deployed position;controlling the position of the retractable blind (102) based on a reference shadow model (120) for the building (124) at the first position;comparing the detected light intensity at the retractable blind (102) with the predicted light intensity of the reference shadow model (120);determining a variation between the detected light intensity at the retractable blind (102) and the predicted light intensity by the reference shadow model (120); andupdating the reference shadow model (120) based on the detected light intensity.

11. A method according to claim 10, further comprising comparing the variation between the detected light intensity and the predicted light intensity of the retractable blind (102) at the first position with one or more other retractable blinds (102) located at different positions on the building (124).

12. A method according to claim 10 or 11, wherein the step of determining the variation between the detected light intensity and the predicted light intensity by the reference shadow model (120) comprises detecting a statistical variation between the detected 5 light and the reference shadow model (120).

13. A method according to any one of claims 10 to 12, wherein the step of updating the reference shadow model (120) based on the detected light intensity comprises applying one or more of statistical tools, machine learning algorithms, outlier detection 10 techniques, and time series analysis.

14. A method according to any one of claims 10 to 13, further comprising controlling the position of the retractable blind (102) based on the updated reference shadow model (120).

15. A method according to any one of claims 10 to 14, wherein the step of detecting light intensity on the retractable blind (102) comprises detecting light intensity using a light sensor (110) selected from the group consisting of a photodetector, a lightdependent resistor (LDR), a photodiode, and a phototransistor.

Images