Patent Description:
It is desired to address or ameliorate one or more shortcomings or disadvantages associated with known systems and methods for controlling fluid supply to a hot water unit.

Document <CIT> discloses a rainwater harvesting system which comprises an above ground rainwater storage tank fixed to a vertical external wall of a building, which is arranged to receive water from a drainage system.

Document <CIT> discloses an electronic controller and a computer-implemented method for a water storage system.

Document <CIT> discloses a water interface unit for interfacing between a complementary water supply and a main water supply including a consumer demand point.

The invention concerns to a hot water unit fluid supply control system according to claim <NUM>. Some embodiments relate to a hot water unit fluid supply control system as defined in the appended dependent claims <NUM> to <NUM>.

The invention concerns a method of controlling fluid supply to a hot water unit according to claim <NUM>. Some embodiments relate to a method of controlling fluid supply to a hot water unit, as defined in the appended dependent claims <NUM> to <NUM>.

Embodiments are described in further detail below, by way of example and with reference to the accompanying drawings, in which:.

Described embodiments relate to methods and systems for controlling a hot water unit, and in particular, controlling fluid supply to the hot water unit. Some embodiments relate to hot water unit fluid supply control systems and some embodiments relate to methods of controlling a hot water unit control system.

Some embodiments relate to a hot water unit fluid supply control system comprising a switching device for selectively controlling fluid supply to the hot water unit and a control unit for controlling activation/deactivation of the switching device. The switching device is coupled to a hot water unit, a rainwater tank and a potable water source and is configured to switch between a first state, to allow fluid communication between the hot water unit and the rainwater tank, and a second state, to allow fluid communication between the hot water unit and the potable water source. The switching device is configured to assume the first state or the second state based on a comparison of fluid characteristic information sensed or detected from the hot water unit by one or more sensors with requirements for the hot water unit. At least one of the one or more sensors is configured to detect fluid temperature in the hot water unit, and the fluid characteristic parameter comprises a temperature value. In some embodiments, the switching device may be configured to assume a first state or second state based on a comparison of detected operations information of a ultraviolet (UV) treatment unit associated with the hot water unit and requirements for the hot water unit. In some embodiments, the switching device is an electrically actuatable switching device and the control unit is configured to transmit a signal to the electric switching device to trigger switching of the switching device. The control unit may also be configured to activate a pump of the rainwater tank when the switching device assumes the first state and to deactivate the pump of the rainwater tank when the switching device assumes the second state. The control unit may also be configured to activate and deactivate a pump of the rainwater tank. For example, the control unit may be configured to activate the pump when the switching device assumes the first state and to deactivate the pump of the rainwater tank when the switching device assumes the second state. In some embodiments, the control unit is configured to activate or deactivate a pump of the rainwater tank to trigger switching of the switching device. Some embodiments relate to methods of controlling such hot water unit control systems.

Although rainwater is often used for purposes such as toilet flushing, clothes laundering or garden watering, it is rarely used for other household purposes unless no other supply option is available. This is primarily due to a concern that untreated rainwater may not be as safe as domestic or potable water. However, by employing the hot water unit fluid supply control system described herein, a reliable supply of hot water may be provided while mitigating the chance of incidental and unintentional consumption of potentially unsafe water by ensuring that the temperature and/or quality of the water in the hot water unit meets an appropriate standard.

Referring to <FIG> and <FIG>, there is shown an installation <NUM> deployed at a building such as a commercial or residential building <NUM> and configured to provide a hot water supply <NUM> to the building <NUM>. The building <NUM> may comprise a roof <NUM> and a gutter <NUM>, which may include a gutter guard (not shown), arranged to collect fluid, such as rain water, from the roof <NUM>.

The installation <NUM> comprises a hot water unit or tank <NUM> coupled to and in fluid communication a potable or drinkable water source <NUM>. The installation <NUM> further comprises a rainwater tank <NUM> coupled to and in fluid communication with the hot water unit <NUM>.

In some embodiments, the installation <NUM> may comprise a UV treatment unit <NUM> in fluid communication with the rainwater tank <NUM> and the hot water unit <NUM>. For example, in some embodiments, fluid conveyed from the rainwater tank <NUM> to the hot water unit <NUM> passes through the UV treatment unit <NUM> before being conveyed to the hot water unit <NUM>. In some embodiments, the UV treatment unit <NUM> may be in fluid communication with the potable water source <NUM> and fluid conveyed from the potable water source <NUM> to the hot water unit <NUM> may pass through the UV treatment unit <NUM> before being conveyed to the hot water unit <NUM>. In other embodiments, fluid extracted from the hot water unit <NUM> passes through the UV treatment unit <NUM> before being conveyed to the building <NUM>.

In some embodiments, fluid from the roof <NUM> and/or collected in the gutter <NUM> and/or collected by other means is conveyed to a leaf catcher <NUM> and/or a first flush system <NUM> before being conveyed to the rainwater tank <NUM>. In some embodiments, the rainwater tank <NUM> is provided with an outlet <NUM> to allow for selective discharge of fluid from the rainwater tank <NUM>. As shown in <FIG> and <FIG>, the rainwater tank <NUM> comprises a pump <NUM>, which when activated, is configured to pump fluid from the rainwater tank <NUM> to the hot water unit <NUM>.

The installation <NUM> comprises a hot water unit fluid supply control system <NUM> for controlling fluid supply to the hot water unit <NUM>. The hot water unit fluid supply control system <NUM> comprises a switching device <NUM>, as shown in <FIG> and <FIG>, coupled to the hot water unit <NUM>, the rainwater tank <NUM> and the potable water source <NUM>. The switching device <NUM> is configured to selectively switch between a first state, which allows fluid communication between the hot water unit <NUM> and the rainwater tank <NUM>, and a second state, which allows fluid communication between the hot water unit <NUM> and the potable water source <NUM>. In some embodiments, the first and second states are mutually exclusive, in that the switching device <NUM> is capable of operating in one or other of the states at any one time, but not both. In some embodiments, the switching device <NUM> may be configured to selectively switch to a third state, which prevents fluid communication between the hot water unit <NUM> and both the hot water unit <NUM> and the potable water source <NUM>. In some embodiments, the switching device <NUM> may be configured to selectively switch to a fourth state to allow fluid communication between the hot water unit <NUM> and an alternative water source, such as a recycled water source. In some embodiments, when the switching device <NUM> assumes the fourth state, fluid communication between the hot water unit <NUM> and both the hot water unit <NUM> and the potable water source <NUM> is prevented.

As shown in <FIG>, in some embodiments, the switching device <NUM> comprises a first inlet <NUM> coupled to a first conduit <NUM> arranged to convey fluid from the potable water source <NUM> to the switching device <NUM>, a second inlet <NUM> coupled to a second conduit <NUM> arranged to convey fluid from the rainwater tank <NUM> to the switching device <NUM> and an outlet <NUM> coupled to a third conduit <NUM> arranged to convey fluid from the switching device <NUM> to the hot water unit <NUM>.

In some embodiments, the UV treatment unit <NUM> is disposed upstream of the hot water unit <NUM> and downstream of the switching device <NUM> such that fluid conveyed from the rainwater tank <NUM> or potable water source <NUM> passes through the UV treatment unit <NUM> before being conveyed to the hot water unit <NUM>. However, in other embodiments, the UV treatment unit <NUM> is disposed downstream of the hot water unit <NUM> and downstream of the switching device <NUM> such that fluid conveyed from the rainwater tank <NUM> or potable water source <NUM> does not pass through the UV treatment unit <NUM> before being conveyed to the hot water unit <NUM> but instead passes through the UV treatment unit <NUM> after being conveyed from the hot water unit <NUM>.

In some embodiments, the switching device <NUM> is an automatic hydraulic switch. The switching device <NUM> may be configured to switch between the first and second states in response to detecting a pressure change in fluid supply from the rainwater tank <NUM>. In some embodiments, a change in pressure of fluid supply from the rainwater tank <NUM> may arise as a result of activation or deactivation of the pump <NUM>. In some embodiments, the switching device <NUM> may comprise an off-the-shelf mechanical changeover valve, such as the AcquaSaver™ manufactured by Beltrami Group Pty Ltd.

The hot water unit fluid supply control system <NUM> further comprises a control unit <NUM>, as exemplified in <FIG>, configured to cause the switching device <NUM> to switch between states. The control unit <NUM> comprises a memory <NUM> comprising program instructions and a processor <NUM> configured to execute the program instructions to cause the control unit to perform operations described herein.

In some embodiments, the control unit <NUM> is arranged to control operations of the pump <NUM> of the rainwater tank <NUM>. For example, the pump <NUM> may activate (turn on) or deactivate (turn off) in response to the action of a suitable pump contactor or relay <NUM> that supplies power from a power source <NUM>, such as a mains power source and/or one or more batteries, to the pump <NUM> under control of the control unit <NUM>. For example, the relay <NUM> may provide power to the pump <NUM> via suitable power cables (not shown) that extend into the rainwater tank <NUM> in a suitable manner. When activated, the pump <NUM> may be configured to pump rainwater out of the rainwater tank <NUM> via the second conduit <NUM> to the switching device <NUM>.

It will be appreciated, however, that if the fluid level in the rainwater tank <NUM> drops below a given level, such as the pump intake, the pump <NUM> may be deactivated, for example to avoid damage. The pump <NUM> may also stop working due to other reasons, such as a power failure. In such circumstances, the resulting change in pressure of fluid supply from the rainwater tank <NUM> would cause the switching device <NUM> to switch between the first and second states, putting the hot water unit <NUM> in fluid communication with the potable water source <NUM>.

In some embodiments, the control unit <NUM> unit may be configured to activate or deactivate the pump <NUM> to thereby cause a change in pressure of supply of fluid from the rainwater tank <NUM>, through the second conduit <NUM> to the switching device <NUM>, detectable by the switching device <NUM>. For example, when the pump <NUM> is activated, the pressure of the supply from the rainwater tank <NUM> is relatively high, causing the switching device <NUM> to assume the first state, allowing fluid to be conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM>. When the pump <NUM> is deactivated, the pressure of the supply from the rainwater tank <NUM> is relatively low, causing the switching device <NUM> to assume the second state, preventing fluid to be conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM> and instead allowing fluid to be conveyed from the potable water source <NUM> to the hot water unit <NUM>.

In some embodiments, the switching device <NUM> may be or may comprise an electrically actuatable switching device and the control unit <NUM> may be configured to transmit a signal to the switching device <NUM> to trigger switching of the switching device <NUM>. The control unit <NUM> may also be configured to activate and deactivate the pump <NUM> of the rainwater tank <NUM>. For example, the control unit <NUM> may be configured to activate the pump when the switching device <NUM> assumes the first state and to deactivate the pump <NUM> of the rainwater tank when the switching device <NUM> assumes the second state. In some embodiments, the control unit <NUM> triggers switching of the switching device <NUM> at substantially the same time or shortly before or after the control unit <NUM> activates or deactivates the pump <NUM>.

In some embodiments, the control unit <NUM> is arranged to control operations of the pump <NUM> of the rainwater tank <NUM> in response to signals received from one or more sensors <NUM>. For example, sensor(s) <NUM> may be in electrical communication with the control unit <NUM> via suitable means, such as via an electrical cable.

In some embodiments, one or more of the sensor(s) <NUM> are configured to sense or detect fluid characteristics of fluid within, exiting or being provided to the hot water unit <NUM> and to provide fluid characteristic information to the control unit <NUM>. According to the invention, at least one of the one or more of the sensors <NUM> comprises a temperature sensor disposed at or in the hot water unit <NUM> and is configured to detect temperature of fluid in the hot water unit <NUM>. In some embodiments, the temperature sensor is provided a top or exit of the hot water unit <NUM>. In some embodiments, at least one of the one or more of the sensors <NUM> comprises a flow sensor disposed at or in the hot water unit <NUM> and is configured to detect flow rate of fluid exiting the hot water unit <NUM>. In some embodiments, at least one of the one or more of the sensors <NUM> comprises a fluid quality sensor disposed at or in the UV treatment unit and/or at or in the hot water unit <NUM> to detect the quality of the fluid of the hot water unit <NUM>. For example, the fluid quality sensor may be configured to sense or detect water quality characteristics such as pH, turbidity, and electrical conductivity.

In some embodiments, one or more of the sensor(s) <NUM> are configured to sense or detect operations characteristics associated with the ultraviolet (UV) treatment unit <NUM> in fluid communication with the hot water unit <NUM> and to provide operations information to the control unit <NUM>. In some embodiments, at least one of the one or more of the sensors <NUM> comprises a UV treatment sensor disposed at or in the UV treatment unit and/or at or in the hot water unit <NUM> to detect operations information associated with the UV treatment unit, for example, an indication of whether or not the UV treatment unit is operating effectively. In some embodiments, the one or more of the sensor(s) <NUM> are configured to sense or detect the efficacy or efficiency of the UV treatment unit <NUM>. For example, the control unit <NUM> may be configured to monitor an output signal of the UV treatment unit to determine whether the UV treatment unit <NUM> is operating effectively. In some embodiments, one or more UV treatment sensors are employed to detect UV light transmission across fluid volume in the UV treatment unit <NUM>. For example, a UV light transmission value may be a percentage transmittance value at <NUM>.

The control unit <NUM> is configured to compare the fluid characteristic information and/or operations information with requirements for the hot water unit <NUM>. Requirements for the hot water unit <NUM> may comprise one or more of a plurality of ranges, set points and/or threshold values, for example, to ensure efficient and/or safe operation of the hot water unit <NUM>. The requirements of the hot water tank <NUM> may be stored in the memory <NUM> of the control unit <NUM>. In some embodiments, the requirements may comprises temperature requirements, fluid flow requirements, fluid quality requirements and/or UV operation requirements.

In some embodiments, the temperature requirements may comprise a threshold fluid temperature, which may be a minimum and/or maximum fluid temperature; the fluid flow requirements may comprise a threshold fluid flow value, which may be a minimum and/or maximum fluid flow value; the fluid quality requirements may comprise a threshold fluid quality value, which may be a minimum and/or maximum fluid quality value; and/or the UV operation requirements may comprise a threshold lamp efficiency value, which may be a maximum and/or minimum lamp efficiency value. In some embodiments, the UV operation requirements may require compliance with a threshold transmittance value, for example, of about <NUM>%. If the detected transmittance value is less than the threshold transmittance value, it may be an indication that the UV treatment unit <NUM> is not operating effectively, for example, due to turbidity and/or lamp age.

In some embodiments, the control unit <NUM> is configured to determine a parameter value from the fluid characteristic information and/or operations information and to compare the fluid characteristic parameter and/or the operations parameter with the hot water tank <NUM> requirements, such as a threshold value, and to determine whether or not to activate or deactivate the pump <NUM> of the rainwater tank <NUM> based on the comparison. Thus, whether or not the switching device <NUM> is caused to assume the first state or the second state is based on the comparison of the parameter with a threshold value.

In some embodiments, the control unit <NUM> may comprise one or more wired or wireless transceivers (not shown) and may be configured to communicate with a remote server (not shown), such as a SCADA system, flow meters and/or other instruments (not shown) associated with water, power or other utilities. In some embodiments, the memory <NUM> may be configured to store a number of set points and/or control parameters for operation of the pump <NUM> and any other components of the hot water unit fluid supply control system <NUM>. In some embodiments, the requirements of the hot water unit <NUM> and/or set points and/or control parameters for operation of the pump <NUM> and/or any other components of the hot water unit fluid supply control system <NUM> stored in the memory <NUM> may be altered or changed locally by the control unit <NUM> or remotely by the remote server (not shown) in communication with the control unit <NUM>. For example, ranges, set points, thresholds and/or control parameters may be altered or changed by the control unit <NUM> in response to instructions received from remote server (not shown). In some embodiments, the control unit <NUM> may be configured to increase or decrease ranges, set points, thresholds and/or control parameters by an specific amount specified by the remote server (not shown) or to a next level predetermined at the control unit <NUM>. In some embodiments, the control unit <NUM> may be configured to replace a stored value for ranges, set points, thresholds and/or control parameters with a value determined and/or provided by the remote server (not shown). For example, in some embodiments, the remote server (not shown) may be configured to predict future usage patterns associated with a particular installation <NUM> based on determined usage patterns, The remote server (not shown) may determine values for the requirements of the hot water unit <NUM> and/or set points and/or control parameters for operation of the pump <NUM> and/or any other components of the hot water unit fluid supply control system <NUM> of the installation based on the predicted usage patterns and transmit a signal to the control unit <NUM> to cause the control unit <NUM> to alter or replace stored values for ranges, set points, thresholds and/or control parameters with determined values.

Referring now to <FIG>, there is shown a process flow diagram of a method <NUM> of controlling a hot water unit, (or more particularly, a method of controlling fluid supply to a hot water unit), the method operable by the control unit <NUM> of the hot water unit fluid supply control system <NUM>, according to some embodiments. In particular, the processor <NUM> of the control unit <NUM> is configured to execute instructions stored in the memory <NUM> to perform the method <NUM>.

The control unit <NUM> is configured to receive sensor readings from the one or more sensors <NUM>, at <NUM>. For example, the sensor readings comprise fluid characteristic information, as discussed above.

The control unit <NUM> is configured to determine one or more parameter values from the fluid characteristic information and to compare the fluid characteristic parameter with the requirements of the hot water tank <NUM>, at <NUM>.

If the control unit <NUM> determines that the fluid characteristic parameter does not meet or comply with the requirements of the hot water tank <NUM>, the control unit <NUM> is configured to determine if the pump <NUM> is activated, at <NUM>. If the control unit <NUM> determines that the pump <NUM> is not activated, the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings. If the control unit <NUM> determines that the pump <NUM> is activated, the control unit <NUM> deactivates the pump, at <NUM> and the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings.

If the control unit <NUM> determines that the fluid characteristic parameter meets or complies with the requirements of the hot water tank <NUM>, the control unit <NUM> is configured to determine if the pump <NUM> is activated, at <NUM>. If the control unit <NUM> determines that the pump <NUM> is activated, the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings. If the control unit <NUM> determines that the pump <NUM> is not activated, the control unit <NUM> activates the pump, at <NUM> and the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings.

The fluid characteristic information comprises temperature information, the control unit <NUM> is configured to determine the temperature of the fluid in the hot water unit <NUM> as the fluid characteristic parameter and in some embodiments the control unit <NUM> is configured to compare the determined temperature to a threshold value, such as a minimum temperature value. If the determined temperature is greater than the threshold value, the control unit <NUM> may be configured to activate the pump <NUM> to thereby cause the switching device <NUM> to assume the first state (or allow the pump to remain activated, whereby the switching device <NUM> would remain in the first state), allowing fluid to be conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM>. If the determined temperature is less than the threshold value, the control unit <NUM> may be configured to deactivate the pump <NUM> to thereby cause the switching device <NUM> to assume the second state (or allow the pump to remain deactivated, whereby the switching device <NUM> would remain in the second state), allowing fluid to be conveyed from the potable water source <NUM> through the switching device <NUM> to the hot water unit <NUM> and preventing fluid being conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM>.

For example, the threshold value or a minimum temperature value may be approximately <NUM>, which is believed to be sufficient to control Legionella and for pathogen kill. Thus, in some embodiments, if the control unit <NUM> detects that the temperature in the hot water tank <NUM> is less than <NUM>, it is configured to deactivate the pump <NUM>, causing a drop in water pressure supply from the rainwater tank <NUM> and the switching of the switching device <NUM> to put the hot water unit <NUM> in fluid communication with the potable supply <NUM>. Once the hot water unit <NUM> has recovered to the target <NUM> temperature, the control unit <NUM> will reactivate the pump <NUM> and accordingly, allow fluid, if available, to flow from the rainwater tank <NUM> to the hot water unit <NUM>.

Similarly, in some embodiments, where the fluid characteristic information comprises fluid flow information, the control unit <NUM> may be configured to determine the flow rate of the fluid exiting the hot water unit <NUM> and to employ the flow rate to monitor and/or determine a volume of fluid being provided to and/or extracted from the hot water unit. For example, the fluid characteristic parameter may comprise a fluid volume. The control unit <NUM> may be configured to compare the determined fluid volume to a threshold value, such as a maximum fluid volume. If the determined fluid volume is less than the threshold value, the control unit <NUM> may be configured to activate the pump <NUM> to thereby cause the switching device <NUM> to assume the first state (or allow the pump to remain activated, whereby the switching device <NUM> would remain in the first state), allowing fluid to be conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM>. For example, the threshold value may be <NUM> for a <NUM> hot water unit <NUM>. If the determined fluid volume is greater than the threshold value, the control unit <NUM> may be configured to deactivate the pump <NUM> to thereby cause the switching device <NUM> to assume the second state (or allow the pump to remain deactivated, whereby the switching device <NUM> would remain in the second state), allowing fluid to be conveyed from the potable water source <NUM> through the switching device <NUM> to the hot water unit <NUM> and preventing fluid being conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM>. For example, the provision of a given or threshold amount of fluid to the hot water unit <NUM> and/or extraction of a given or threshold amount of fluid from the hot water unit <NUM> may serve as an indication that the temperature of the fluid in the hot water tank <NUM> is likely to drop to a value below a desired or the threshold value, such as <NUM> degrees. The control unit may therefore be configured to switch off the pump <NUM>, and hence trigger the switching device <NUM> to disallow fluid from the rainwater tank <NUM> to be conveyed to the hot water unit <NUM> and allow fluid from the potable water source <NUM> to be conveyed to the hot water unit <NUM>, as a pre-emptive measure to aid recovery time of the hot water unit <NUM>.

Similarly, in some embodiments, where the fluid characteristic information comprises fluid quality information, the control unit <NUM> may be configured to determine a measure of the quality of the fluid in the hot water unit <NUM> as the fluid characteristic parameter and to compare the determined quality measure to a threshold value, such as a minimum PH value. If the determined quality measure is greater than the threshold value, the control unit <NUM> may be configured to activate the pump <NUM> to thereby cause the switching device <NUM> to assume the first state (or allow the pump to remain activated, whereby the switching device <NUM> would remain in the first state), allowing fluid to be conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM>. If the determined quality measure is less than the threshold value, the control unit <NUM> may be configured to deactivate the pump <NUM> to thereby cause the switching device <NUM> to assume the second state (or allow the pump to remain deactivated, whereby the switching device <NUM> would remain in the second state), allowing fluid to be conveyed from the potable water source <NUM> through the switching device <NUM> to the hot water unit <NUM> and preventing fluid being conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM>.

Referring now to <FIG>, there is shown a process flow diagram of a method <NUM> of controlling a hot water unit, (or more particularly, a method of controlling fluid supply to a hot water unit,) the method operable by the control unit <NUM> of the hot water unit fluid supply control system <NUM>, according to some embodiments. In particular, the processor <NUM> of the control unit <NUM> is configured to execute instructions stored in the memory <NUM> to perform the method <NUM>.

The control unit <NUM> is configured to receive sensor readings from the one or more sensors <NUM>, at <NUM>. For example, the sensor readings may comprise operations information, as discussed above.

The control unit <NUM> is configured to determine one or more parameter values from the operations information and to compare the operations parameter with the requirements of the hot water tank <NUM>, at <NUM>.

If the control unit <NUM> determines that the operations parameter does not meet or comply with the requirements of the hot water tank <NUM>, the control unit <NUM> is configured to determine if the pump <NUM> is activated, at <NUM>. If the control unit <NUM> determines that the pump <NUM> is not activated, the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings. If the control unit <NUM> determines that the pump <NUM> is activated, the control unit <NUM> deactivates the pump, at <NUM> and the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings.

If the control unit <NUM> determines that the operations parameter meets or complies with the requirements of the hot water tank <NUM>, the control unit <NUM> is configured to determine if the pump <NUM> is activated, at <NUM>. If the control unit <NUM> determines that the pump <NUM> is activated, the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings. If the control unit <NUM> determines that the pump <NUM> is not activated, the control unit <NUM> activates the pump, at <NUM> and the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings.

In some embodiments, where the operations information comprises an indication of whether or not the UV treatment unit <NUM> is operating effectively, the control unit <NUM> may be configured to determine the indication as the operations parameter and to compare the operations parameter to a threshold value, such as a lamp efficiency value. If the determined lamp efficiency value is greater than the threshold value, the control unit <NUM> may be configured to activate the pump <NUM> to thereby cause the switching device <NUM> to assume the first state (or allow the pump to remain activated, whereby the switching device <NUM> would remain in the first state), allowing fluid to be conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM>. If the determined lamp efficiency value is less than the threshold value, the control unit <NUM> may be configured to deactivate the pump <NUM> to thereby cause the switching device <NUM> to assume the second state (or allow the pump to remain deactivated, whereby the switching device <NUM> would remain in the second state), allowing fluid to be conveyed from the potable water source <NUM> through the switching device <NUM> to the hot water unit <NUM> and preventing fluid being conveyed from the rainwater tank <NUM> through the switching device <NUM> to the hot water unit <NUM>.

Referring now to <FIG>, there is shown a process flow diagram of a method <NUM> of controlling fluid supply to a hot water unit <NUM>, (or more particularly, a method of controlling fluid supply to a hot water unit), the method operable by the control unit <NUM> of the hot water unit fluid supply control system <NUM>, according to some embodiments. In particular, the processor <NUM> of the control unit <NUM> is configured to execute instructions stored in the memory <NUM> to perform the method <NUM>.

The control unit <NUM> is configured to receive sensor readings from the one or more sensors <NUM> of an installation <NUM> and to store the readings in the memory <NUM>, at <NUM>. For example, the sensor readings may comprise fluid characteristic information associated with fluid in the hot water unit, as discussed above. In some embodiments, the fluid characteristic information is indicative of a volume of usable water in the hot water unit.

The control unit <NUM> is configured to determine usage information from the fluid characteristic information of the sensor readings, at <NUM>. The usage information may comprise a volume of fluid being drawn from the hot water unit <NUM> during a timeframe. For example, the timeframe may be an hourly period. The control unit <NUM> may be configured to store the determined usage volumes during a timeframe over a period of time. For example, the usage information may comprise a volume of fluid drawn from the hot water unit <NUM> during each hour of a day, for a number of days or week.

The control unit <NUM> is configured to determine a behaviour or usage pattern for the installation for the period of time based on the usage information, at <NUM>. For example, the control unit <NUM> may the usage pattern to infer or predict a likely volume of fluid to be drawn for a particular hour on a particular day, for example, a predicted volume of fluid to be drawn from the hot water unit on a Tuesday between 9am and 10am. In some embodiments, the behaviour or usage pattern may comprise a plurality of timeframes and a predicted volume of fluid associated with each timeframe for a period of time. For example, the usage pattern may comprises a plurality of usage entries, wherein each usage entry comprising fluid characteristic information indicative of a volume of usable water in the hot water unit for a timeframe. For example, the timeframe may be a period of time and in some embodiments, may be associated with a particular time period of a day, or a particular day or the week, month or year.

The control unit may be configured to continue to record sensor readings and dynamically update or change the predicted values to refine the determined behaviour or usage pattern over time. For example, the usage pattern may be updated periodically or in response to receiving fluid characteristic information associated with fluid in the hot water unit from one or more sensors. In some embodiments, additional information, such as weather forecast, predicted or known times during which the premises won't be occupied or when there may be less or more demands due to school holidays or visitors etc, may be employed to better inform a determination of the usage or behaviour pattern.

The control unit <NUM> is configured to receive current sensor readings from the one or more sensors <NUM> of an installation <NUM>, at <NUM>, where the current sensor readings are indicative of a quality of the fluid in the hot water unit <NUM> and a quantity of the fluid in the hot water unit <NUM> at a particular time. For example, in some embodiments, the current sensor readings indicative of a quality of the fluid in the hot water unit are temperature readings indicative of a temperature of the fluid in the hot water unit <NUM>. In some embodiments, the current sensor readings indicative of the quantity of fluid in the hot water unit are flow rate readings indicative of flow rate value and/or a fluid volume value.

The control unit <NUM> is configured to determine whether a volume of useable water in the hot water unit <NUM>, at <NUM>. In some embodiments, the control unit <NUM> may be configured to compare the volume and temperature of the fluid in the hot water unit <NUM> with threshold values, for example, as may be stored in memory <NUM>, to determine the volume of usable water. For example, if it is determined that the fluid in the hot water unit <NUM> has a temperature of less than a threshold value deemed safe, for example, <NUM> degrees, it may be determined that the volume of useable water in the hot water unit <NUM> is <NUM>.

The control unit <NUM> determines whether the volume of useable water is greater than the predicted volume of water required for the timeframe, at <NUM>. For example, the control unit <NUM> compares the determined volume of usable water with the predicted volume of water required for the timeframe that corresponds with the time associated with the current sensor readings.

If the control unit <NUM> determines that the volume of useable water is not greater than the predicted volume of water required for the timeframe, the control unit <NUM> is configured to determine if the pump <NUM> is activated, at <NUM>. If the control unit <NUM> determines that the pump <NUM> is not activated, the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings. If the control unit <NUM> determines that the pump <NUM> is activated, the control unit <NUM> deactivates the pump <NUM>, at <NUM> and the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings.

If the control unit <NUM> determines that the volume of useable water is greater than the predicted volume of water required for the timeframe, the control unit <NUM> is configured to determine if the pump <NUM> is activated, at <NUM>. If the control unit <NUM> determines that the pump <NUM> is activated, the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings. If the control unit <NUM> determines that the pump <NUM> is not activated, the control unit <NUM> activates the pump <NUM>, at <NUM> and the method returns to step <NUM> and the control unit <NUM> awaits receipt of further sensor readings.

In some embodiments, the control unit <NUM> may be configured to transmit the sensor readings received at <NUM> to the remote server (not shown) to allow the remote server (not shown) to perform data analysis and usage prediction analysis. The remote server (not shown) may generate a usage pattern and transmit the usage pattern to the control unit <NUM> for use in the method of <NUM>. Thus, the remote server (not shown) may perform step <NUM>, and in some embodiments step <NUM>, as opposed to or in addition to the control unit performing these steps.

Claim 1:
A hot water unit fluid supply control system comprising:
a hot water unit (<NUM>);
a rainwater tank (<NUM>);
a potable water source (<NUM>);
a switching device (<NUM>) coupled to the hot water unit (<NUM>), the rainwater tank (<NUM>) and the potable water source (<NUM>), the switching device configured to selectively switch between a first state, which allows fluid communication between the hot water unit (<NUM>) and the rainwater tank (<NUM>), and a second state, which allows fluid communication between the hot water unit (<NUM>) and the potable water source (<NUM>);
one or more sensors (<NUM>) and
a control unit (<NUM>) configured to:
receive fluid characteristic information associated with fluid in the hot water unit (<NUM>) from said one or more sensors (<NUM>); and cause the switching device (<NUM>) to assume the first or second state based on a comparison of a fluid characteristic parameter of the fluid characteristic information with requirements of the hot water unit (<NUM>), wherein the control unit (<NUM>) is configured to activate a pump (<NUM>) of the rainwater tank (<NUM>) to cause a pressure change in fluid supply from the rainwater tank (<NUM>) and thereby cause the switching device to assume the first state and to deactivate a pump (<NUM>) of the rainwater tank (<NUM>) to cause the switching device to assume the second state,
wherein at least one of the one or more sensors (<NUM>) is configured to detect fluid temperature in the hot water unit (<NUM>), and wherein the fluid characteristic parameter comprises a temperature value.