Shower system

Abstract

Shower System A control system for a shower comprises a variable temperature setting means for producing water at a system temperature and an electronically controlled valve, the controller being arranged to control the valve so as to reduce the flow of water by a small amount (so as to be not, or barely, noticeable to a user) at a point after commencement of the shower. It also extends to a controller for a shower, where the controller may be remote from, and may control a standard shower A small reduction in the flow is often unnoticed by the shower user once they have acclimatized to the shower, and can result in a notable reduction in energy usage. This has benefits in electricity costs, as well as an improved house efficiency score under schemes such as the UK Standard Assessment Procedure (SAP).

Description

[0001] Shower System

[0002] The present invention relates to shower systems, as may typically be used in residential bathrooms, or in commercial premises such as gymnasiums, swimming pools, campsites or anywhere where electric or mixer showers might be used. More particularly, it relates to shower systems that have electrical controllers for controlling the temperature, including electric showers where an electrical heating element is used to heat an incoming cold water supply, and to mixer showers having an electronic control of a mixer valve used for mixing hot and cold incoming water supplies to provide shower water to a user, where there is a desire by the homeowner, or shower operator, to reduce energy usage of the shower system.

[0003] Electric showers are ubiquitous in households and other places, due to their convenience in providing a quick source of hot water, for as long as required. Mixer showers, where a source of pre-heated hot water is mixed with a cold water source, to produce water for showering at a desired temperature, are also commonplace. These showers often have a manual mixer that sets the temperature of the shower water. Electronic mixer showers are now becoming commonplace, where an electronic circuit is used to control a mixer valve and so control the shower water temperature.

[0004] In the UK it is commonplace for a residential property to be assessed for its energy efficiency, with a “Standard Assessment Procedure” (SAP) score providing an efficiency rating for the property. SAP is currently in use alongside the emerging Home Energy Model (HEM), with both expected to operate in parallel during a transitional period before HEM ultimately replaces SAP as the primary assessment methodology. Other countries have similar schemes. The UK SAP scoring is currently based on a six minute shower. A shower is rated dependent upon its nominal power rating, and also its water flow rate and so by reducing these, the SAP score can be improved.

[0005] However, there is a reluctance for users to have colder showers, or showers with a weaker flow rate, as they may see it as uncomfortable. Therefore, higher flow showers, using more energy, either electrical heating energy, or an increased usage of hot water from a hot water tank, are still popular. This leads both to a more expensive shower experience, and to a poorer energy performance.

[0006] Embodiments of the invention have the object of addressing one or more of the aboveshortcomings of the background art, and / or to provide an alternative shower system.

[0007] According to a first aspect of the present invention there is provided a control system for a shower, comprising a variable temperature setting means for producing shower water at a system temperature, an electronically controlled valve, for providing a variable flow rate of water at a shower output, and a processor for controlling the variable temperature setting means and the electronically controlled valve, and, wherein the control system is arranged to:

[0008] without input from a user, adjust the valve, so as to reduce system flow rate provided at the output of the shower by a small amount at a time point after the start of the shower, and for at least some of the remaining duration of operation of the shower;

[0009] and to further control the variable temperature setting means to maintain or reduce the system temperature.

[0010] Note that the system temperature is the water temperature at the output of the shower, which the control system attempts to maintain. It may be the temperature of the water as demanded by a user, at least at an initial stage of the shower, but it may deliberately deviate from that demanded by the user, such as, for example to save energy by reduction of the system temperature slightly, where a slight change is defined as a change that is judged to be not, or barely perceptible to the average user.

[0011] The variable temperature setting means will typically be a power modulator arranged to control flow of electricity to an electrical heating element arranged to heat water from a cold water source connected thereto, but may also be an electronically controlled mixer unit arranged to mix a hot water input and a cold water input to provide water at an output having a system temperature between that of the two inputs. Such electrical heating elements, incorporated into the water flow, to form an electrical water heater, are commonplace in shower systems, and will be known to the skilled person. Similarly, electrically controlled mixer showers are also commonplace, and are often used in environments such as swimming pools, gymnasiums, commercial shower, and of course in residential properties also.

[0012] The processor may preferably comprise a microcontroller, arranged to control the valve, and the variable temperature setting means, and also to act as a timer to time the various flow and electrical power reductions, and to monitor temperature through the use oftemperature sensors. It may be programmed to implement a control loop to maintain a system temperature at an output of the shower as flow rate is reduced. The control loop may use a PID algorithm, as explained elsewhere herein, and as would be understood by a normally skilled person.

[0013] It has been found that the energy usage of a shower may be reduced, by reducing the flow rate of water through the shower, at some point after the start of the shower, whilst maintaining or even reducing the system temperature slightly (where the definition of “slight change” is as explained above), and it can be done without having any significant impact on the quality of the shower as perceived by the user. Indeed, it may not even be noticed at all. Body skin temperature tends to increase during the early part of a shower, which may also contribute to any subsequent reduction in temperature being less noticeable.

[0014] In some embodiments, the controller reduces the water pressure at the output of the shower by controlling the valve to reduce the flow of water through the heating element or mixer, and, for electric showers, simultaneously reduces the electrical power provided to the heating element so as to maintain the system water temperature. Advantageously, the time point at which the pressure is reduced may be between 30 seconds and 4 minutes from the start of the shower. The time point may be, in some embodiments, approximately 2 minutes from the start of the shower.

[0015] Preferably, the water flow is reduced from the starting flow rate to a reduced flow rate over a period of between 10 seconds and 2 minutes. In some embodiments the flow rate is reduced over a period of approximately one minute.

[0016] The flow rate reduction may be, in some embodiments, typically between a range of 5% to 20%, with reductions in this range being regarded as a small amount, with around 10% being preferred. Such small amounts are amounts that will typically be not noticed, or barely noticed, by a user, especially if done gradually over a period of seconds, as mentioned above.

[0017] It has been found that small reductions in flow rate, that occur some way in to the shower duration tend not to be noticed by a user, or for the user to regard them as insignificant. This is especially so if the flow is reduced gradually, as mentioned above. However, in some embodiments the flow may be reduced by a small amount in a more sudden fashion.In some embodiments the control system for the shower (also known as the shower controller) may further be arranged to compensate for the drop in flow rate of the shower by arranging for a shower hose outlet nozzle to reduce the number of open holes though which water exits the nozzle as the flow rate drops. This then tends to bring the pressure of the water at the nozzle back up, depending on the proportion of holes that are closed. The shower may be arranged to control the number of outlet holes that are open in the nozzle by any suitable means. This may be, for example, a hydraulic, pneumatic, or mechanical connection from the shower unit, through the outlet hose, to the nozzle. Thus, the shower associated with the controller may have a specially adapted hose that has a control cable or pipe (that may preferably sit within the hose), to provide the coupling.

[0018] The shower associated with the shower controller may therefor incorporate a mechanical, hydraulic or pneumatic driver that couples to the hose, and hence to the nozzle, that is arranged to control, under direction from the controller, the nozzle, and how many outlet holes are active at any one time. The driver may be, for example, a servo motor attachable to a cable drive, or a hydraulic or pneumatic device arranged to vary the fluid pressure down a control pipe. Thus the effective pressure within the shower hose may be adjusted accordingly, with higher pressures being associated with few active outlet holes, and lower pressures being associated with a greater number of active outlet holes. The shower controller can therefore control the shower head nozzles in harmony with the pressure reduction as so that the user feels no difference in pressure reduction on the skin. The nozzle may have an internal adjustable shield or plate that is moveable between positions, and in one position a greater number of holes are open and active as opposed to another position. The mechanical, hydraulic or pneumatic coupling may therefore be arranged to attach to the shield to change its position according to the driver within the shower.

[0019] It will be appreciated that, with an electrically heated shower, to avoid water temperature increasing as flow is reduced, energy supplied to the heating element in the shower needs to be reduced accordingly. This may be done in an open loop fashion, whereby the controller estimates or measures the change in flow, and reduces the power supplied to the heating element accordingly, dependent upon the estimate or measured flow rate reduction. Alternatively, it may be done using a temperature sensor arranged to measure the output flow of water from the shower (or into the shower in the case of a mixer shower), and use the sensor information in a feedback loop to adjust the water temperature to maintain a desired system temperature. The feedback loop may operate in known fashion, such as byusing a proportional-integral-derivative (PID) control loop to maintain the system temperature, or may use other arrangements, as would be known to a normally skilled person.

[0020] With a mixer shower, the valve may be arranged to operate on the water supply to the shower after or at the mixer. This will help to maintain system temperature as flow rate is reduced. However, temperature can still vary with flow rate, for example due to differing pressures in the hot and cold water supplies to the mixer unit. Thus there may be a feedback loop and temperature sensor as described above, or it may have an open loop arrangement again as described above. In some embodiments there may be more than one valve, with a valve connected to both the incoming hot and cold feeds to the mixer.

[0021] Note that the system temperature need not remain fixed. It may be controlled, by the controller, and may be arranged to vary as described herein.

[0022] There may be, in some embodiments, a temperature sensor, such as a thermocouple, or a temperature dependent resistor, or some other temperature sensor, located so as to be able to measure the temperature of the water as or after it exits the heating element or mixer (depending on whether the shower has electrical heating or a mixer). Thus it is able to provide to the controller an indication of the temperature as will be experienced by the user of the shower, so that the controller can use the measurement to control the system water temperature, such as in the feedback loop mentioned above. Some embodiments may have multiple temperature sensors, for example a sensor within the heating element (where present), so that the controller can determine whether the water within the heating element has reached the desired temperature for operation of the shower. Temperature sensors may be at other locations, such as in the shower cubicle in which the shower is installed, or in a shower hose, or in one or more water inlet pipes, so that the controller knows the temperature of the incoming water. The temperature sensors may provide an input to a temperature feedback loop as discussed above.

[0023] The one or more sensors may be connected to the controller via a wired connection, or may use a wireless connection protocol, such as Bluetooth, WIFI, or Zigbee, or some other protocol.Note that the processor may be separate from the temperature controller, or may comprise the same element. The processor may therefore act as a temperature controller, and also control the valve.

[0024] In some embodiments, along with the flow reduction, the controller is arranged to provide a first system water temperature, as chosen by a user, and at a time point where a user will be deemed to have become accustomed to the temperature, to reduce the system water temperature to a second temperature that is judged to be not, or barely perceptibly different from the first temperature by the user. This may occur before, during, or after the reduction in flow rate that is made. The perception of the user is such that, by allowing them to become accustomed to the first temperature, a slight reduction is not noticed, or is barely noticed, and a saving of energy is made. This saving (over the cost of a shower not implementing this embodiment ) increases the longer the shower goes on for.

[0025] In some embodiments the temperature change may be controlled not by monitoring temperature, but by instead (for electric showers) reducing the power provided to the heating element, by an amount likely to create the desired reduction in system temperature. Similarly, for mixer showers the temperature may be changed by instructing a mixer valve to adjust the ratio of hot to cold water being allowed through. Preferably however there will be at least one temperature sensor within the system.

[0026] In some embodiments the time point at which the temperature is changed is between 30 seconds and 4 minutes into the shower duration. This range has been found to allow the temperature to stabilise, and for the user to become accustomed to it. Preferably, in some embodiments, the time point is approximately 2 minutes into the shower duration.

[0027] In some embodiments the temperature reduction is between approx. 0.5 and approx. 2 degrees Celsius. This has been found to provide a power saving, whilst being generally not noticeable at the smaller reduction, and only marginally noticeable at the larger reduction. In some conditions, such as if the room is warm, a larger reduction may be attainable without being perceived by the user. In some embodiments the reduction may be set to 1 degree Celsius. The degree of reduction may, in some embodiments, be adjustable by the user. The degree of reduction may be, for example, 0.25°C, 0.5°C, 1°C, 1.5°C, 2°C, 3°C, 4°C, or more, or anything in between. Temperature reductions within the range of up to around 4°C have generally been found to be either not perceptible, or barely perceptible by users.In some embodiments the reduction may be selectable by the user, and may range from a very slight reduction, such as 0.5°C, all the way to an unheated shower, if desired.

[0028] In some embodiments the temperature reduction is performed in a gradual manner over a duration of between 15 seconds and 2 minutes from the time point. Preferably, it may occur over the interval of approximately one minute. This typically makes the change even less noticeable to the user.

[0029] In some embodiments, following a period of running the shower at a reduced system flow rate, or flow rate and temperature, the flow rate or temperature is increased back to the initial system flow rate or temperature. This may be done for example to provide an improved shower experience at the end of the shower when a user will be typically be rinsing soap from themselves, and so particularly an increased flow rate is beneficial to accomplish this more quickly.

[0030] Some embodiments of the shower may incorporate a means for pumping air into the water flow. It has been found that doing so can provide a perceived increase in water pressure for the shower user. Thus, such embodiments may be arranged to compensate for any flow rate reduction by adding air into the flow, to reduce any such perceived flow rate reduction by the user.

[0031] In some embodiments having an electrical water heater, the flow rate reduction may be an average flow rate reduction, with the flow being pulsed between the full flow level and a reduced flow level and back, so constituting a pulse cycle. On average, over the cycle, there is therefore a reduction in flow rate. Thus, the valve may be arranged to pulse the flow at a rate typically between 3 and 10 cycles per second. When the valve is controlled to provide a pulsing effect, the controller is arranged to match power provided to the heating element to one of the measured, expected, instantaneous or average water flow rate, so as to maintain a desired system water temperature. The system water temperature may be arranged to stay constant for the shower duration, or may be arranged to drop, for example as described above to reduce even further the power required during the shower.

[0032] The power provided to the heating element may be chosen so as to maintain a desired average system temperature throughout the pulse cycle. For example, if the average flowrate is reduced due to the pulsing of the flow, then the power supplied to the heating element can be reduced accordingly to maintain the desired system temperature.

[0033] In those embodiments having a mixer, when the valve is controlled to provide a pulsing effect, the controller is arranged to reduce water drawn from the hot water source to compensate for the reduced average flow of water, so as to maintain the system temperature.

[0034] Preferably, in some embodiments of the invention the flow rate at a lowest flow part of the pulse cycle is between 60% and 85% of the flow rate at a maximum flow part of the pulse. This provides a pleasing pulsing effect, and reduces average water flow, and so enables the amount of hot water to be used or generated to be reduced accordingly.

[0035] Advantageously, in some embodiments arranged to control an electrical heater, the electrical power to the heater is controlled using a pulse-width modulation technique. This allows for a fine power control, using, for example, a solid state relay, or thyristor control of the electrical power, and thus also fine control over the output water temperature.

[0036] In some embodiments the valve comprises a solenoid, arranged to provide a variable water flow rate through the heating element or mixer. There may be, in some embodiments, be a plurality of solenoids. The or each solenoid may be arranged to provide a variable, or different, flow rate according to the status (either open, or closed, or in some reduced opening state) of each of the solenoids.

[0037] Alternatively, in some embodiments, the valve comprises a rotary valve having a motor drive. This provides a differing flow rate through the valve according to a rotational position of the valve as driven by the motor.

[0038] In some embodiments having an electrical water heater, the valve is arranged, when a user initially switches the shower on, to restrict flow of water through the heating element until water within the heating element is near to the system water temperature required at the output of the heating element. This provides for a more comfortable shower, with the water supplied to the user getting up to temperature more quickly than if it wasn’t held back, albeit with a slight delay in the flow of water when the shower is activated. This also will oftenresult in a slight power saving, as typically a user will tend to finish the shower slightly earlier than if they are in it at the start with a colder initial flow.

[0039] In some embodiments having an electrical water heater, when a user issues a command to the shower to switch it off, the controller is arranged to maintain the flow of water for a short time, with the electrical power to the heating element switched off. The duration of the extra water flow following the command is chosen so that the hot water within the shower system (comprising the shower hose, and in the heating element and output pipework), is passed through to the user, and it detects or estimates that cooler water is about to be exiting the nozzle and then stops the water flow and switches off. In this way, the water that has been heated by the shower is not wasted.

[0040] In some embodiments a cold water inlet pipe of the shower is arranged to connect to a waste water heat recovery unit. A waste water heat recovery unit sits in the waste water flow path, and acts as a heat exchanger, with the waste water being used to pass its residual heat to incoming water. When installed so as to provide water to the shower unit then it will provide a warmer cold-water feed to the heater, and so less energy is required in providing water at the system temperature.

[0041] In some embodiments the shower control system may be installed within a shower unit, such as an electric shower unit as typically found in many homes in the UK. The controller may, in embodiments used to control a mixer shower, be fitted with, or nearby a mixer valve used to control the relative proportions of hot and cold water.

[0042] In some embodiments some elements of the control system may be installed remotely from the shower that it is arranged to control. These elements may comprise power modulation to control the system water temperature, and the processor, arranged to control the power modulation, and, via a remote connection (such as a wireless, or wired connection), a valve either in the shower, or on a water inlet to the shower.

[0043] Conveniently, in some embodiments, the control system, or some elements thereof, is built into an isolating power switch arranged to supply electricity to an electric shower.

[0044] In some embodiments the control system may be fitted between an isolating switch, and the shower itself. It may then work as described above. In other embodiments the controller may be fitted within the shower itself. In other embodiments, it may be fitted before anisolating switch, or in other words, electrically between the isolating switch and an electrical supply coming into the property. It may be fitted, for example, in or near a consumer unit or distribution board for a property.

[0045] Advantageously, the variable temperature setting means may in some embodiments comprise a power modulator arranged to modulate the electrical power supplied to a shower heating element. The modulator may be arranged to provide pulse width modulation of the power. The modulator may comprise a solid state relay, a triac, or thyristor, solid state relay, or any other suitable type of power controller.

[0046] As explained above, in some embodiments the variable temperature setting means may comprise a transformer, arranged to provide a variable supply voltage to the shower. The transformer may be located integral with, or remotely from, the shower unit itself. In some embodiments the transformer may comprise a toroidal transformer, with a wiper to vary a point at which on the toroid an output voltage is supplied to the rest of the shower. In some embodiments the transformer may comprise a multi-tapped transformer, with a switch to select a particular tap to provide an output voltage to the rest of the shower.

[0047] In certain embodiments where the control system is located remotely from the shower (such as in an isolation switch unit), there may also be an auxiliary interface module (AIM) located within the shower assembly, which may be either retrofitted, or built in to the shower in factory. Thus, some embodiments may comprise an auxiliary interface module, arranged to be retrofitted to a shower, and further arranged to provide voltage regulation for at least some componentry within the shower. The module is configured to condition power and signals for existing actuators or electronic mixer components, including solenoid-actuated valves such as a water-inlet solenoid. This may be desirable if some of the shower elements, such as said actuators do not behave in a desired way with reduced power levels created by modulation of the incoming power as provided by the shower controller. The AIM may include an energy-storage element, such as a capacitor or battery, to provide short-duration power ride-through during supply modulation. It may also act to smooth, or current-shape incoming electrical power to reduce audible noise and undesired pulsation of the actuators. Communication between the AIM and the remote controller may be wired or wireless, and the module may be powered from existing shower circuitry. Locating the AIM proximal to an actuator within the shower can improve control stability and reduce audible artefacts. In some arrangements the AIM may provide a bypass or fail-safe state so the shower reverts to native operation on loss of power or communications.The control system may also be used with electrically controlled mixer showers, and may be arranged to control a mixer valve used to determine the overall flow rate, and the ratio of hot to cold water supplied to a connected shower head. The control system may be arranged to control the valve to reduce the system water temperature after a time period after commencement of the shower, as explained above. The control system may be installed along with, or alongside the valve, or may be located remotely, and connected thereto using a wired or wireless connection protocol.

[0048] The control system may further comprise a water flow detector for determining the start of a shower. The flow detector may be remote from the other elements of the control system, and may be connected thereto by wired or wireless means. Alternatively, the flow detector may be contained along with the other elements of the control system, where the control system is mounted suitably proximal to a feed to the shower.

[0049] For both the electric and the mixer shower variants the control system may have one or more sensors, such as temperature sensors arranged to measure system water temperature delivered to the user, and / or the room temperature. The temperature sensors may be wired to the processor, or may be in communication therewith wirelessly, using, for example the protocols mentioned elsewhere herein.

[0050] The temperature sensors may be used to select, or influence, the time point at which the control system is arranged to make a change to the system water temperature or flow rate. The sensors may also be arranged to select the amount of temperature change made to the system water temperature. For example, in a warm shower room, as determined by a room temperature sensor, the degree of temperature change may be slightly increased, without affecting the water temperature change perceived by a shower user. A change in temperature may also be made sooner into the shower. Likewise, on a cooler day, the system temperature change may be smaller, or may be made later in the shower duration.

[0051] The remotely located control system may be pre-programmed with different algorithms. One example may start a timer when current flow, or water flow, if a flow detector is installed, is detected, and may base its temperature reduction based on the timer. Others may start a timer when current is detected, but also use temperature information to adapt the timing of how it changes the water output temperature based on the temperature readings. Others may monitor input water temperature particularly if a waste-water heatexchanger is being used, as that will tend to warm the incoming flow as the shower progresses, allowing energy to be reduced.

[0052] According to a second aspect of the invention there is provided a shower, having a shower control system according to the first aspect of the invention.

[0053] In some embodiments the shower may be arranged to be fed from a water inlet pipe connected to a waste water heat recovery unit. Some embodiments may incorporate a waste water heat recovery unit within the embodiment, couplable to the shower.

[0054] Note that features and elements of the first aspect may be applied, where appropriate, to the second aspect of the invention, and vice versa.

[0055] For both aspects, a temperature sensor may be arranged to monitor a water input temperature. This may be done for example to reduce the electrical power provided to an electrical water heating element if the input water temperature rises, whilst maintaining a desired system water temperature. Similarly, a mixer valve may be adjusted accordingly. Such water temperature changes can occur for various reasons as would be appreciated by a normally skilled person, but one significant one is the use of waste-water heat recovery systems, whereby the shower water may drain via a heat exchanger, to impart its residual heat into an incoming water flow feeding the shower.

[0056] In some embodiments, the control system may be arranged to infer a temperature drop due to the use of a current sensor, that detects the start of a shower and which adjusts its variable water temperature setting means to maintain or reduce system water temperature based on an expected rise in input water temperature.

[0057] Thus, some embodiments may work without requiring a temperature sensor to measure shower input cold water temperature. The processor may be programmed to have a timer used to decrease power supplied to the variable water temperature setting means whilst also reducing the flow rate slightly (as described above), after a set time after the current sensor has indicated that a shower has started. The set time, and degree of power reduction may be based on commonly found thermal conditions in systems that use a waste-water heat recovery system. The control system may have multiple settings for the time, and power, that may be selectable by a shower installer or user, so as to choosesettings that best match with the thermal conditions of the water system in a given installation. Each property has different length of pipe runs, different types of heat recovery system etc., different shower types etc., but it has been found that the thermal characteristics of a property don’t change significantly, so that once a suitable setting for the time and power regulation for a given installation have been found, they are likely to remain sufficiently consistent. Thus, temperature regulation of a shower, that takes account of the use of a waste-water heat recovery system, can be achieved without temperature measurement.

[0058] Some elements of the shower control system may be located within, alongside, or remotely from the shower it is controlling, as described with other aspects of the invention. It may be located for example in an isolation switch unit, in a consumer unit or distribution board, or at any other suitable point in the electrical system.

[0059] Of course, some embodiments may have a temperature sensor, which can measure the temperature of input cold water feeding the shower. In some embodiments the means for measuring the input water temperature is located remotely from the temperature controller. It may communicate temperature information by a wired or wireless means, as described in relation to other embodiments of the invention. These embodiments may use the temperature reading to directly control the timing and degree of power modulation applied to maintain a desired system temperature as the input water temperature rises.

[0060] Embodiments of the invention are further described hereinafter, by way of example only, with reference to the accompanying drawings, in which:

[0061] Figure 1 diagrammatically illustrates, at a high level, the elements of a shower controller according to an embodiment of the present invention using an electrical heating element;

[0062] Figure 2 diagrammatically illustrates, at a high level, the elements of a shower controller according to another embodiment of the present invention using a water mixer unit;

[0063] Figure 3 shows a graph of water flow rate in an embodiment of the invention that reduces flow rate in a phased manner during the shower;Figure 4 shows a graph of system water temperature versus time of an embodiment of the invention that reduces the system water temperature as well as flow rate in a phased manner during the shower;

[0064] Figure 5 shows a graph of water pressure, and electrical power draw in an embodiment of the invention that has an electrical heating element, and is switchable to provide a pulsing water flow; and

[0065] Figure 6 diagrammatically illustrates a shower that is able to control an attached nozzle to selectively activate or deactivate some water outlet holes, to correct for a perceived pressure drop when flow rate is reduced.

[0066] Shown in Figure 1 is a top level block diagram of components in an embodiment of the invention. These components are contained in a shower unit located in a shower, as is typical of electric showers currently. There are of course other components that would be required to implement a practical shower system, such as safety circuitry, power conditioning etc. that would be appreciated and understood by a person skilled in the art.

[0067] The shower 100 comprises of a water inlet 102, that comes from a cold water supply, and a water outlet 104 that connects in use to a shower hose. The water inlet 102 feeds a water heater 106, that is arranged to heat the water to a system temperature as determined by a controller circuit 108. The controller circuit 108 has an electrical input (not shown), and an electrical output feed 110 to a heating element within the water heater. When the circuit 108 provides a suitable power supply to the heating element the water within the heater will be heated up, according to well known principles. The control circuit has a processor arranged to control the various other elements of the controller in known fashion.

[0068] A temperature sensor 112 is fitted to the heater, and is able to measure the temperature of water present therein. It is located such that it reads the water temperature at the output of the heating element.

[0069] The heater has an outlet pipe 114 through which the heated water can flow when the shower is activated. A valve 116 sits between the outlet pipe 114 and the shower outlet 104. The valve is able to stop the flow altogether, or to provide a full flow, or to allow areduced flow. The valve has an electrical connection to the controller 108, that permits the controller to set the valve into a desired state, and so control the flow of water through it. Note that in some embodiments the valve may sit on the inlet side of the shower, or may sit remotely therefrom.

[0070] The controller further has an On / Off switch 118, and a temperature setting knob 120. The switch 118 is used by a user to activate the shower, i.e. to start and stop the flow of water, and the temperature knob 120 is used to set a desired user water temperature.

[0071] The temperature of the water at the output is under the control of the controller 108, and this is known herein as the system water temperature.

[0072] Figure 2 shows a further embodiment of the invention. A key difference between this embodiment and that of Figure 1 , is that the hot water is provided by a connected hot water source, rather than having an internal water heater. In more detail, the shower unit 130 comprises an electromechanical mixer unit 132 having a first input 134 from a hot water source, such as a hot water tank, and a second input 136 from a cold water source, and having an output 138. The shower further comprises a controller 140, a temperature sensor 142 and a valve 144 that is able to vary the flow rate of water at the shower output 146. The output 138 from the mixer unit comprises of a mix of the two input water supplies. The mixer unit is an electromechanical device, that has a motorized mixing valve that is able to control the ratio of the two input water supplies that comprise the output water supply. The motorized mixing valve is connected to the controller 140, and the controller is able to adjust the ratio by providing appropriate control signals to the mixer. The temperature sensor 142, at the output of the mixer 132, connects to the controller, and enables the controller to set a desired output water system temperature, and to vary the system temperature as described herein. The valve 144 is adjusted by the controller 140 to reduce the flow of water slightly at some point after the start of the shower, as discussed herein.

[0073] The operation of the shower according to the embodiment shown in Figure 1 will now be described, with reference to Figure 3 The shower controller is arranged to provide a saving of the energy used, as compared to a standard prior art shower, whilst still providing a fully satisfactory shower experience for the user. When a user enters the shower, they will select a desired water temperature using knob 120, and will then switch the power on using switch118 (or they may do this in the reverse order of course). Figure 3 shows water flow rate at the output of the shower against time on the x axis. Again, the shower starts (once the output water temperature has stabilized), at a system temperature that matches the temperature demanded by the user. Valve 116, (or 144, depending on the embodiment) is fully open at this time, shown as phase (a) on Figure 3. The flow rate is determined by the water pressure and pipe and valve characteristics, with the open valve 116, 144. At a time period approximately two minutes into the shower, the controller is arranged to reduce the flow of water through the heater or mixer, by partially closing the valve 116, or 144. This is shown as phase (b) in Figure 3. The shower controller 108, 140 is arranged to maintain the same system temperature at the output by controlling the power to the heating element. The partial closing of the valve 116, 144 takes place over the course of around 10 seconds. The reduced water flow, coupled with the maintenance of the same system temperature, results in a water saving proportional to the flow reduction. It has been found that a flow reduction of around 10% tends not to be noticed by a user, especially if the reduction is done over a period of several (such as around ten) seconds, although of course it can be done more quickly, and can be even done instantaneously, still with a good chance that the pressure drop will not be noticed.

[0074] Another embodiment of the invention uses a similar hardware setup to that of Figure 1 or Figure 2, and is shown in Figure 4. This has the same flow rate reduction as described in relation to Figure 3, but also has a controlled, slight temperature reduction also. The initial start up procedure is the same as for the embodiment above, with the user choosing a temperature and activating the flow. When they do this, the water will start to flow, and the controller 108 provides power to the heater through connection 110, to heat the water up to the temperature as chosen by the user. This can be seen at phase (a) of Figure 4, which is a graph of system water temperature (i.e. water temperature at the output of the shower), with time on the x axis. If the water temperature is significantly colder than the demanded temperature then the water heater will be driven at full power to bring it up to temperature as quickly as possible. As the water temperature at the output approaches the desired temperature then the controller will start to modulate the power provided to the heater so that the temperature does not significantly overshoot the demanded temperature. When the demanded temperature is achieved at the output of the heating element the controller will provide suitable electrical control of the heater to maintain this temperature, as shown at phase (b) of Figure 4. It uses the temperature sensor 112 to measure the water temperature, and so a feedback system is employed. This then is the current systemtemperature of the shower, and so the system temperature is the same as the temperature demanded by the user. Stage (a) of the process typically takes place in a few seconds.

[0075] After a period of two minutes from the start of the shower, the controller then starts a power saving process, whereby it slowly reduces the power supplied to the heater, so as to bring the system temperature down by around 1°C from that of the demanded temperature. This is shown at phase (c) in Figure 3, with the system temperature ramping down over the duration. It does this over a period of one minute in a broadly linear fashion. It has been found that such a reduction, if done in this graduated manner, is typically not noticeable by a user of the shower. Therefore, for the rest of the duration of the shower, i.e. during phase (d), there will be a lower electrical draw due to the reduced effort required to heat the water to this lower system temperature. Note of course the reduction in flow rate that also takes place as described above, further contributing to the lower power draw.

[0076] It will be apparent that the description above of the operation of the embodiment of Figure 1, applies, mutatis mutandis, to the embodiment of Figure 2, but with appropriate changes to the apparatus for providing the heated water for the output of the shower. Where the controller acts to reduce the power provided to the heating element of the embodiment of Figure 1 , it will instead adjust the mixer unit to provide a greater ratio of cold water to hot water at the mixer output in the embodiment of Figure 2.

[0077] It will be apparent that in the embodiments shown, the monitoring of the water temperature at either the input or output of the shower, along with having a temperature controller to maintain a system temperature using a feedback loop, means that if the shower system is connected to a waste water heat recovery system, then the temperature controller will account for this by reducing the electrical power supplied to a heating element, so providing an electrical power saving.

[0078] A further embodiment of the invention again uses a similar hardware setup to that of Figure 1 or Figure 2. Here, the valve 116, or 144, is chosen such that it is able to be rapidly switched between a full-flow mode of operation and a partial flow, where the flow rate is reduced to approximately 80% of the full flow rate. Figure 5 shows a graph of the water flow, and the power consumption of the shower with time. The solid line shows the water flow, and the dashed line shows the power consumption. It can be seen that the shower starts off in a regular fashion, with a continuous flow rate. A user then presses a button on a control panel, which connects electrically to the control circuitry 108, which then activatesthe valve 116, 144 so as to pulse the flow rate, as shown. The circuitry also attempts to keep the temperature at the same level as prior to the activation, using a temperature feedback technique, such as that described herein. Given that the flow rate is now pulsing between 100% and 80%, the average flow rate is less than when the water was flowing steadily. This means that the electrical power supplied to the heater 106 must be reduced accordingly if the water temperatures isn’t to rise, or equivalently, the mixer setting 132 must be reduced to decrease the percentage of hot water making up the water at the output. And it will be appreciated that this then provides a power saving over the power used during the steady state flow. This is shown by the dashed line in the graph.

[0079] In this embodiment the user is free to switch the pulsing effect on or off, but due to the pleasant feeling, the user is likely to engage the pulse mode quite often, so resulting in a power saving. It is also understood that a user is less likely to perceive the flow rate reduction when in the pulse mode, and so typically will generally be happy to keep it on most of the time. Note that some embodiments may have the controller arranged to engage the pulse mode by default, or to engage the mode if the shower was last switched off whilst in the mode.

[0080] Note that this graph, like the others shown herein, is merely representational, and the axes are not drawn to scale. The pulse rate in this embodiment is approximately 10Hz.

[0081] The valve 116, 144 is a rotary valve, that rotates an aperture between open and closed states, which provides a restriction on the total flow of water to the output of the shower. The valve has a switchable bypass pipe, thus providing a flow of water when the rotary valve is closed. This is arranged to be the low point of the flow during the pulse cycle, and when it and the rotary valve are both open, the flow is at its peak. The use of a rotary valve makes for a quieter pulsing effect as compared to the use of a solenoid valve.

[0082] Figure 6 shows another embodiment of the invention, whereby a shower that reduces flow rate, such as that described in relation to Figure 4, is able to compensate for a perceived reduction in shower pressure by the user. A shower unit 150, containing a heating element and control circuitry (not shown) has a shower hose 152 connected to the water outlet of the shower. The shower hose has a nozzle 154 at a remote end from the shower unit, having exit holes 156 through which water may flow. The flow of water is determined by a valve 158 in the shower unit as explained in relation to various embodiments above. In addition, the shower unit contains a servo motor 160 attached to a cable 162 that runs inside the shower hose. The servo is able to pull on the cable 162, that is connected at itsfar end to a mechanism 164 in the nozzle that is moveable by the cable to different positions. The mechanism consists of a plate that is rotatable between a first position in which the nozzle has all of its exit holes free to allow water to pass through, and a second position in which around 20% of them are closed off. Other embodiments may be arranged to close off different percentages of the exit holes, such as 10%, or 30% for example.

[0083] When a shower that is arranged to reduce its flow rate at an interval, so as to save energy, and having the mechanism of Figure 6, is first switched on, then it will run initially at its full pressure, and at the set system temperature. Then, as explained above, it will reduce its flow rate from some point, such as from around 2 minutes in to the shower through suitable control of the valve 158. When the shower reduces its flow rate, then the user may notice the drop in pressure from the nozzle. To counter this, this embodiment simultaneously closes off a portion of the active exit holes in the nozzle, such that the apparent pressure from the nozzle is similar to that prior to the flow rate reduction. There will of course be a reduced flow of water to the user, but it will be at a broadly similar pressure at the exit of the nozzle, and so is likely to be less noticeable to the user. And of course, as the system temperature is maintained, or even reduced with the reduced flow rate, there is a lower energy cost.

[0084] Another embodiment may have an air pump, arranged to provide a flow of air in the water stream passing through the hose. This flow of air can provide an effect similar to that of increasing flow rate of the shower. Therefore, such embodiments are incorporated with a valve for reducing flow rate at a point during the shower, as explained above. As the flow rate of the water is reduced, then the air pump is activated, so as to compensate for the reduced pressure at the nozzle, to attempt to maintain the perceived water shower pressure as experienced by the user.

[0085] The reductions in flow rate, and optionally the system temperature with it, provide measurable reductions in power drawn from the electrical system once they have cut in. A shower according to some embodiments of the invention, therefore provides benefits not just in being cheaper to run, but also in scoring well on environmental assessments of properties that have such showers fitted.

[0086] A typical shower generally follows three main stages:

[0087] a) Wetting the body (starting the shower, getting wet),

[0088] b) Lathering up (applying soap / shampoo and scrubbing),

[0089] c) Rinsing off (washing away soap and shampoo).For a typical 6 minute shower, this may comprise (with timings being approximate of course):

[0090] Time (minutes) Activity

[0091] 0:00-1:00 Get wet - Step under the shower, fully wet hair and body.

[0092] 1:00-3:30 Apply soap and wash - Shampoo hair, soap body, scrub

[0093] 3:30-6:00 Rinse thoroughly Rinse out shampoo and soap. Focus on hair, body, underarms, and feet.

[0094] Another embodiment uses this rough timing to provide a period, for the second stage, of a reduce water flow rate, but which increases the flow rate back up to the initial flow rate for the final rinse stage. This provides for a power saving during the second stage (due to the temperature being maintained at the system temperature, which may also include a reduction in the temperature as per embodiments described above), and also reduces amount of soap being washed off the body before it is desired. Thus the showering experiences is both more satisfying to the user, and also saving energy over prior art showers.

[0095] It has been found that in some instances, where a shower user has a timer that shows their time spent in the shower, then the shower duration tends to be shorter. Some embodiments may have therefore a display on the shower unit that shows the duration of the shower.

[0096] In the UK the SAP efficiency rating score can be improved an appreciable amount by use of a shower according to some embodiments of the invention, giving a significant benefit to those buying, selling or renting out properties. The SAP system of the UK allots a standard set of performance criteria to a shower, and under normal circumstances it treats all electric showers similarly. However, some embodiments of the invention deviate from the standard model by allowing an increase in SAP points during specific assessments. Features such as those described above provide energy efficiency gain over a standard electric shower, thereby boosting the overall SAP score. Further improvements in the SAP score can be obtained if a waste-water heat recovery unit is fitted, to extract the heat from waste water and use it to heat a cold water feed to the shower.

[0097] The invention may be further understood from the following paragraph:A control system for a shower comprises a variable temperature setting means for producing water at a system temperature and an electronically controlled valve, the controller being arranged to control the valve so as to reduce the flow of water by a small amount (so as to be not, or barely, noticeable to a user) at a point after commencement of the shower. It also extends to a controller for a shower, where the controller may be remote from, and may control a standard shower A small reduction in the flow is often unnoticed by the shower user once they have acclimatized to the shower, and can result in a notable reduction in energy usage. This has benefits in electricity costs, as well as an improved house efficiency score under schemes such as the UK Standard Assessment Procedure (SAP).

[0098] The functions described herein as provided by individual components could, where appropriate, be provided by a combination of components instead. Similarly, functions described as provided by a combination of components could, where appropriate, be provided by a single component.

[0099] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0100] Features, integers, or characteristics described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

22Claims1. A control system for a shower, comprising a variable temperature setting means for producing shower water at a system temperature, an electronically controlled valve, for providing a variable flow rate of water at a shower output, and a processor for controlling the variable temperature setting means and the electronically controlled valve, and, wherein the control system is arranged to:without input from a user, adjust the valve, so as to reduce system flow rate provided at the output of the shower by a small amount at a time point after the start of the shower, and for at least some of the remaining duration of operation of the shower;and to further control the variable temperature setting means to maintain or reduce the system temperature.

2. A control system for a shower as claimed in claim 1 wherein the time point at which the flow rate is reduced is between 30 seconds and 4 minutes from the start of the shower.

3. A control system for a shower as claimed in claim 2 where the time point at which the flow rate is reduced is approximately 2 minutes from the start of the shower.

4. A control system for a shower according to any of the above claims wherein the system water temperature is initially, at the start of a shower, arranged to provide a first output water temperature, as chosen by a user, and at a time point where a user will be deemed to have become accustomed to the temperature, to reduce to a second temperature that is judged to be not, or barely perceptibly different from the first temperature by the user.

5. A control system for a shower according to claim 4 wherein the time point is between 30 seconds and 4 minutes into the shower duration.

6. A control system for a shower according to claim 5 wherein the time point is approximately 2 minutes into the shower duration.

7. A control system for a shower according to any of claims 4 to 6 wherein the temperature reduction is between 0.5 and 2 degrees Celsius.

8. A control system for a shower according to any of claims 4 to 7 wherein the temperature reduction is performed in a gradual manner over a duration of between 15 seconds and 2 minutes from the time point.

9. A control system for a shower as claimed in claim 8 wherein the time period is approximately 1 minute.

10. A control system for a shower as claimed in any of the above claims, wherein, following a period of running the shower at a reduced flow rate, the flow rate is increased back to the initial system flow rate.

11. A control system for a shower as claimed in any of the above claims wherein the controller is arranged to control the valve to provide a pulsing water effect, wherein the variable temperature setting means is adjusted to maintain a system water temperature at the output of the shower.

12. A control system for a shower as claimed in claim 11 , wherein, when the valve is controlled to provide a pulsing effect, the controller is arranged to adjust the variable temperature setting means based on the measured, expected, or average water flow rate, so as to maintain a desired system temperature.

13. A control system for a shower as claimed in claim 11 or claim 12 wherein the flow rate at a lowest flow part of the pulse cycle is between 60% and 85% of the flow rate at a maximum flow part of the pulse.14 A control system for a shower as claimed in any of the above claims wherein the valve comprises a solenoid, arranged to provide a variable water flow rate through the heating element.

15. A control system for a shower as claimed in any of claims 1 to 13 wherein the valve comprises a rotary valve having a motor drive.

16. A control system for a shower as claimed in any of the above claims wherein the variable temperature setting means comprises a power modulator arranged to control the flow of electricity to an electrical heating element arranged to heat up water from a cold water source connected thereto.

17. A control system for a shower as claimed in claim 16 wherein the electrical power is controlled using a pulse-width modulation technique.

18. A control system for a shower as claimed in any of claims 1 to 15 wherein the variable temperature setting means comprises of a mixer arranged to mix a hot water input and a cold water input to provide water at an output having a system water temperature between that of the two inputs.

19. A control system for a shower as claimed in any of the above claims and further comprising one or more temperature sensors, arranged to monitor at least one of a) a water temperature at an output of the shower, and b) a water temperature at an input of the shower, and further arranged to use measurements therefrom to adjust or maintain a desired system temperature, or time point at which the system temperature is changed.

20. A control system for a shower as claimed in claim 19 wherein the one or more temperature sensors are mountable remotely from the controller, and connectable thereto by wired or wireless mean.

21. A control system for a shower as claimed in any of the above claims wherein the control system is located remotely from a shower that it is arranged to control.

22. A control system for a shower as claimed in claim 20 or 21 , wherein the control system further comprises current measurement circuitry and a timer, and is arranged to detect a start of a shower by measurement of current drawn, and further to use the timer to set a time after commencement of a shower, at which the system temperature is reduced.

23. A shower having a shower control system as claimed in any of the above claims.

24. A shower as claimed in claim 23 wherein a water inlet pipe of the shower is arranged to connect to a waste water heat recovery unit.

25. A shower as claimed in claim 23 or 24 and further comprising a waste water heat recovery unit couplable thereto.

Images