Indicating Levels Relating to a Power System

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from European Patent Application No. 07 252 809.4, filed 13 July 2007, the whole contents of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to indicating levels relating to a power system, in particular to indicating levels of energy/power generation/consumption relating to a power system.

2. Description of the Related Art

Display apparatus are known that are configured to display a level of energy/power consumption to a user of a power system. In this way, it is possible for a user to be made aware of the extent to which they are consuming energy/power and to present the user with information that enables the user to identify an opportunity to take appropriate measures in order to reduce energy/power consumption. For example, when leaving a residence an occupier may notice the energy/power consumption appears to be abnormally high which would in turn suggest that an appliance has been left on by mistake.

Some power users also generate electrical power locally from solar panels and other generation apparatus. The desirability of showing energy/power consumption and generation has been identified. However, difficulties exist in terms of presenting this information in a meaningful way.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of the present invention, there is provided display apparatus for indicating levels relating to a power system, comprising: a first indicator configured to indicate a level of energy/power consumption, and a second indicator configured to indicate a level of energy/power generation; said first indicator and said second indicator are arranged in close proximity to facilitate a comparison between energy/power consumption and energy/power generation, and at least one of said first indicator and said second indicator is shown against a scale that gives greater emphasis to lower levels and lesser emphasis to higher levels.

In an embodiment, both the first indicator and the second indicator share a scale that gives greater emphasis to lower levels and lesser emphasis to higher levels. In a preferred embodiment, the scale is logarithmic.

According to a further aspect of the present invention, there is provided a method of providing a display for indicating levels relating to a power system, comprising the steps of: indicating a level of energy/power consumption by means of a first indicator; indicating a level of energy/power generation by means of a second indicator; arranging said first indicator and said second indicator in close proximity to facilitate a comparison between power consumption and power generation; and showing at least one of said first indicator and said second indicator against a scale that gives greater emphasis to lower levels and lesser emphasis to higher levels.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Figure 1 shows an environment in which a user of a power system is taking a glance at energy display devices configured to indicate levels relating to the power system;

Figure 2 shows a schematic of energy display indicators;

Figure 3 shows a schematic representation of the electrical power system installed within the environment of Figure 1;

Figure 4 details a processor shown in Figure 3; Figure 5 shows a scale of a display apparatus;

Figure 6 shows a display device;

Figure 7 shows details procedures performed by the processor of Figure 4;

Figure 8 shows further details of procedures performed by the processor of Figure 4;

Figure 9 details a routine identified in Figure 7;

Figure 10 shows a further display device;

Figure 11 shows further features of the display device of Figure 10; and

Figure 12 shows the environment of Figure 1 again, but at a different time of the day.

DESCRIPTION OF THE BEST MODE FOR CARRYING OUT THE

INVENTION Figure 1 An environment is shown in Figure 1 , in which a user of a power system is taking a glance at energy display devices configured to indicate levels relating to the power system. In this example, the environment is a domestic residence. Display apparatus for indicating levels relating to a power system is located within the building. The display apparatus comprises a first indicator configured to indicate a level of energy/power consumption and a second indicator configured to indicate a level of energy/power generation.

A user 103 is shown preparing to leave the building through door 104.

Before actually leaving the residence, the user takes a glance at the display apparatus. In this scenario, energy display devices 101 and 102 are visibly located upon a wall within a room of the building. Display device 101 includes a first indicator configured to indicate a level of energy/power consumption and a second indicator configured to indicate a level of energy/power generation.

The first indicator and the second indicator are arranged in close proximity to facilitate a comparison between energy/power consumption and energy/power generation.

Display device 102 includes a third indicator configured to indicate a level of energy/power generation. In this example, the second indicator indicates a level of energy/power generation from photovoltaic technology and the third indicator indicates a level of energy/power generation from solar- thermal technology.

Figure 2

Figure 2 shows a schematic of energy display indicators. Indicator 201 represents energy/power consumption and indicator 202 represents energy/power generation.

In many countries, local power generation from renewable sources is encouraged. Therefore, it is possible for a user to obtain payment for power supplied to an external source, such as a national grid, at a rate that is higher than the user must pay for receiving power from that external source.

Consequently, a resident may gain financially if the environment is optimised so as to maximise power generation while at the same time minimising power consumption.

As is well known with environments of this type, peak internal power consumption demands tend to be relatively high but for short durations,

whereas power generation tends to be of a lower level but for longer durations. Consequently, throughout the day, the overall sum may be positive in that more power is being generated and supplied to an external source compared to the total amount of power received from the external source. In order to encourage the development of this situation, it is advantageous for a user to be presented with information so as to ensure that optimum use is being made of the power generating capabilities. It is particularly useful for a user to be able to see energy/power consumption and energy/power generation information when the user is about to leave their residence. The information is presented in order for the user to identify whether unnecessary power consumption is occurring and to help remind the user to look for potential power saving opportunities and act to reduce power consumption. By arranging the first indicator and the second indicator in close proximity, a comparison between energy/power consumption and energy/power generation is facilitated.

Figure 3

A schematic representation of the electrical power system installed within the environment of Figure 1 is illustrated in Figure 3. A first interface 301 receives power from an external source and a second output interface 302 supplies locally generated power to the external source. In this example, electrical power is generated by an array of photovoltaic solar collectors 303, possibly mounted on the roof of the residence. The photovoltaic solar collectors 303 generate a varying direct current supply that is converted to alternating current and generally regulated by an inverter 304. Power received from the external source, via input interface 301 is supplied to a regulator 305, which also receives generated power from the inverter 304. A first power

measuring device 306 measures consumed power and provides an indication of this consumed power to a processor 307. Similarly, a second power measuring device 308 measures generated power and also provides an indication of this generated power to the processor 307. Regulator 305 receives power both from the external source and from the generated source. Power is received from regulator 305 and supplied to distributor 309, which typically includes a collection of fuses or circuit breakers etc. The regulator 305 is configured to ensure that the internal requirements are always met and that priority is given to supplying power to the distributor 309. Ideally, all of this power is provided by the generated power received from inverter 304. In reality, it is likely that power will be required from the external source when activities are occurring within the dwelling, whereas at other times, particularly during the day, power will be supplied via regulator 305 to the output interface 302.

Figure 4

Processor 307 of Figure 3 is detailed in Figure 4. Processor 307 includes a central processing unit 401 , such as an appropriately programmed PIC processor. Processing unit 401 is connected to an internal memory device 402 via a system bus 403. An input interface 404 interfaces input devices 405 and 406 to the system bus 403. Similarly, output interface 407 interfaces output devices 408 and 409 to the system bus 403. Input circuits 405 and 406 may be configured to receive input voltages and to perform an analog to digital conversion so as to supply digital signals to the input interface 404. Output circuits 408 and 409 may perform a latching function such that they are periodically supplied with an output value, which is then latched and maintained as an output value until the next updated value is received.

The display apparatus may receive data by means of a wireless communication protocol. In an embodiment, data is transmitted in accordance with the ZigBee protocol (an implementation of the IEEE 802.15.4 protocol), however, Bluetooth or another appropriately configured radio transmission protocol may be used. The display apparatus may also transmit data in a similar manner.

Figure 5

Figure 5 shows a scale of a display apparatus. Scale 501 gives greater emphasis to lower levels and lesser emphasis to higher levels. Scale 501 allows a user to more easily determine a lower level of energy/power consumption. This approach serves to encourage a user to take appropriate measures in order to reduce incidents of lower levels of energy/power consumption. This action serves to reduce the financial loss to the user through power consumption. Scale 501 allows a user to more easily determine a lower level of energy/power generation. This approach serves to encourage a user to take satisfaction from operation of their local power generation source.

Power consumption tends to be of a relatively higher level but for a short duration, whereas power generation tends to be of a relatively lower level but for a longer duration. In a power system that includes a local power generation source, the understanding by the user of the input/output flow of the power system is facilitated by means of giving greater emphasis to lower levels and lesser emphasis to higher levels. For example, a user has traditionally been more concerned about ensuring that appliances that consume a relatively high level of power are switched off than ensuring that appliances that consume a relatively low level. The user has followed this

philosophy on the basis that it is an effective way for them to achieve a reduction in power consumption. In addition, the user has experienced disappointment at the perceived lack of efficiency of their local power generation installation as a result of the local power generation installation operating at a level lower than the maximum rated level.

By giving greater emphasis to lower levels and lesser emphasis to higher levels, the user can more easily see the difference that lower levels of energy/power consumption/generation make to the overall sum of energy/power consumption and energy/power generation. In this way, the user can more easily observe the balance of power output to power input of the power system. As a result, the user is more motivated to ensure both appliances that consume a relatively high level of power and appliances that consume a relatively low level are switched off. The scale thus assists the user to become more confident that implementing this strategy will result in an observable achievement in, and improved overall sense of, efficient use of the power system and associated financial advantage.

Figure 6

A display device is illustrated in Figure 6. The device includes a first indicator configured to indicate a level of energy/power consumption, and a second indicator configured to indicate a level of energy/power generation.

The first indicator and the second indicator are arranged in close proximity to facilitate a comparison between energy/power consumption and energy/power generation. At least one of the first indicator and the second indicator is shown against a scale that gives greater emphasis to lower levels and lesser emphasis to higher levels.

Display device 601 includes a first indicator 602 and a second indicator

603. First indicator 602 and second indicator 603 share a scale 604 that gives greater emphasis to lower levels and lesser emphasis to higher levels. Preferably, and in this example, scale 604 is logarithmic.

In a preferred example, first indicator 602 is implemented as a first set of light emitting devices, and second indicator 603 is implemented as a second set of light emitting devices. A level is indicated by a number of illuminated light emitting devices from the respective set. In a preferred example, the first set of light emitting devices is configured to emit light of a first colour and the said second set of light emitting devices is configured to emit light of a second colour. In a preferred colour combination, the first colour is blue and the second colour is yellow. Preferably, the light emitting devices comprise light emitting diodes.

As shown, the scale may include a substantially curved portion. In this illustrated example, the scale is substantially circular. A range of power generation/consumption values ranging from zero watt to 20 kilowatt is shown.

The first set of light emitting diodes of the first indicator is arranged in a first locus. The second set of light emitting diodes of second first indicator is arranged in a second locus that is radially displaced from the first locus. In this example, the second locus is the outer locus. As shown in the embodiment of Figure 6, the first indicator 602 and the second indicator 603 are arranged in close proximity so as to facilitate a comparison between energy/power consumption and energy/power generation. In the illustration of Figure 6, 500 watt of power is being generated (represented by the illumination of yellow LEDs up to an including the 500 watt mark), whereas 100 watt of power is being consumed (represented by the illumination of blue LEDs up to the 100 watt mark). In a preferred embodiment, when the level of energy generated exceeds the level of energy consumed, an

animated display occurs, the illuminated light emitting devices indicating power generation that extend beyond the illuminated light emitting devices indicating power consumption pulse or flash to show the amount of electricity being exported to an external source. An indication of this type serves to highlight to the user when the power system is providing a financial gain.

It is to be understood that an alternative arrangement of indicator and scale may be utilised to present the described advantageous effects of a display device.

In an alternative arrangement, it is possible to show a complete region, such as a square, being populated by coloured LEDs, the total number of which are illuminated being dependent upon the degree of power consumption/generation. As generation increases, more yellow LEDs would be illuminated and as consumption increases more blue LEDs would be illuminated. It would be possible for the illumination to be initiated from a bottom left corner and then diagonally until the whole square is illuminated. A problem with this proposal is that it creates difficulty in terms of providing a numerical representation. In a preferred embodiment, the first indicator and the second indicator relate to a shared scale. In this way, it is possible for a quick comparison to be made of the amount of power being generated and the amount of power being consumed. With the two values being shown against a shared scale, it is clear to see which of the two is the greater, that is to say whether a user has achieved a preferred condition in which more power is being generated than the degree of power being consumed.

As previously stated, it is preferred for the shared scale 604 to give greater emphasis to lower levels and lesser emphasis to higher levels. Thus, in the preferred embodiment shown in Figure 6, the first three LEDs to be illuminated represent a range of zero watt to 20 watt. The next three represent

a range of 20 watt to 50 watt, the next three represent a range of 50 watt to 100 watt, the next three represent a range of 100 watt to 200 watt, the next three represent a range of 200 watt to 500 watt, the next three 500 watt to 1 kilowatt, the next three 1 kilowatt to 2 kilowatt, the next three 2 kilowatt to 5 kilowatt, the next three 5 kilowatt to 10 kilowatt and the final three from 10 kilowatt to 20 kilowatt. Thus, using this logarithmic approach, it is possible to show relatively low levels of power generation and power consumption on a shared scale, where it is also possible to show relatively high levels of power consumption; it being appreciated that high levels of power consumption will occur when, for example, cooking or heating water etc. In this way, the logarithmic scale provides a non-linear scale.

In alternative approaches to achieving a similar effect, it would be possible to change the total range of the scale such that the full-scale could represent 1 kilowatt of power when this is considered to be appropriate or, alternatively, a full-scale could represent 10 kilowatt or 50 kilowatt etc.

Appropriate re-labelling of the scale would be necessary, although with an appropriate variable display this would be possible. However, it is understood by the inventor that the logarithmic representation as shown in the preferred embodiment of Figure 6 represents a preferred approach in that it places fewer demands on the capabilities of the user.

A further alternative approach would be to use rings of rotating LEDs. In accordance with this approach, having reached the full-scale of, say 10 kilowatt, the dial of LEDs would effectively lap and result in a second run of LEDs being illuminated. Thus, a first lap could show usage from zero to 10 kilowatt with a second lap showing usage from 10 to 20 kilowatt. Again, the inventor is of the opinion that such a solution is less advantageous than the logarithmic approach adopted by the preferred embodiment of Figure 6.

Display device 601 includes further features in addition to the first and second indicators 602, 603. The display apparatus is configured to present a first display indicating an instantaneous level, and a second display indicating an average level. Preferably, the display apparatus is configured to allow a user to switch between said first display and said second display. The display apparatus is configured to present a numerical display of a numerical value. Preferably, the display apparatus is configured to allow a user to selectively show said numerical display.

In a preferred embodiment, a button 605 is presented such that when pressed by a user, a display illuminates showing the total generation of energy over a predetermined period. The period in question is identified by a display 606 which, in this example, shows the Figure "30", representing a duration of 30 days. In this example in response to activation of button 605, a numerical representation is provided within the region indicated at 607, the numerical representation showing the amount of power generated over the last 30 days.

In this illustrated example, region 607 is located substantially centrally of the display (within first and second loci 701 and 702). However, when not activated, it is preferable for an outer cover of the display to present a smoked appearance such that the display region 607 is not visible. In a preferred embodiment, a numerical value is displayed by means of at least one seven- segment display element. When display region 607 is visible, this may be in addition to or in place of another display.

In a preferred embodiment, a button 608 is provided. In this example in response to activation of button 608, a percentage figure of power generated to power consumed is displayed, preferably within region 607 of the display.

Again, this may be averaged over the displayed 30 day period. It is to be appreciated that the period of which values are averaged may be variable. The

arrangement of a display device may require a user to press down a button for the duration of a predetermined period in order for the desired response to be obtained. Once activated, a display may be shown for a predetermined duration only.

Figure 7

Figure 7 shows procedures performed by a processing unit. The procedures will be described with reference to the components of Figures 3 and 4. In a preferred embodiment, the display apparatus includes a button which when pressed makes a change to displayed values such that average generation/consumption values are displayed in preference to instantaneous generation/consumption values.

A question is asked at step 701 as to whether this button has been pressed. If answered in the affirmative, an appropriate routine is called, as detailed in Figure 9. Alternatively, if a press is not detected, the question asked at step 701 is answered in the negative resulting in control being directed to step 703. At step 703, power generation calculations are serviced whereafter at step 704 consumption calculations are serviced. The operation of steps 703 and 704 are performed on a periodic basis (possibly every second) therefore a wait state is entered at step 705. After completing the wait state at step 705, a question is asked at step 706 as to whether a shutdown command has been received resulting in the process terminating when answered in the affirmative. Alternatively, when answered in the negative, control is returned to step 701 and the procedure is repeated. Service generation procedures at step 703 are substantially similar to service consumption procedures at step 704.

Figure 8

Figure 8 details procedures performed by a processing unit. Procedures 703 of Figure 7 will be described with respect to Figure 8, it being appreciated that these are substantially similar to consumption procedures at step 704 of Figure 7. At step 801 a generation input value is read derived from monitoring device 308 and digitised by circuit 405. At step 802 the value is stored in a fashion which effectively associates the stored value with a time at which the value was taken. In this way it is possible for averaging procedures to be effected, as detailed with respect to Figure 5. At step 803 a rounding up process is performed so as to generate an integer value. This integer value

(with rounding) approximates a linear representation of the degree of power being generated. However, in accordance with a preferred aspect of the present invention, the representation is scaled in a non-linear fashion so as to provide greater emphasis on lower levels of generation/consumption and lesser emphasis on higher levels of generation/consumption. The look up table stored within memory device 402 allows any non-linear function of this type to be implemented. However, in a preferred embodiment the relationship is substantially logarithmic. Having generated the logarithmic representation at step 804, the resulting output is supplied to latch 408. The output value is held within latch 408 thereby maintaining a constant signal to the display device until the next refresh occurs, typically one second later.

Figure 9

Figure 6 details the routine called at step 702 of Figure 2. In response to the integration button being pressed, instantaneous power values are replaced with an average power value, that may also be interpreted as an energy value representing the total sum of energy generated over a predetermined period,

such as a day, a week or a month.

At step 901 stored values read from memory device 402 are added together. Thereafter at step 902 the sum is divided by the length of the interval, thereby producing a daily average. An output is produced at step 903 and provided to latch 408. The display is maintained for a predetermined period of time by the process entering a wait state at step 904 whereafter control is returned at step 905.

Figure 10 An example of display device 102 is shown in Figure 10. The display device includes a third indicator 1001 to indicate configured to indicate a level of energy/power generation from solar-thermal technology. In this example, the general configuration of the third indicator represents a tank of water. The third indicator is implemented as a set of light emitting devices, such as LED's, configured to emit light of a first colour and to emit light of a second colour.

The light emitting devices may emit light of a first colour, representing cold water, or light of a second colour, representing hot water. In an example, the first colour indicates a water temperature of less than 40 degrees Celsius whilst the second colour indicates a water temperature of 40 degrees Celsius or above. Preferably, the colour blue indicates cold water and the colour red indicates hot water. The light emitting devices are arranged in segments, such as segment 1002, such that any particular segment may be shown as being cold or hot. In this example, a total of ten (10) segments are provided but the actual number may vary between applications. A level of temperature of the water contained in the tank is indicated by a proportion of light emitting devices illuminated to emit of the first colour to light emitting devices illuminated to emit light of the second colour. In an

example, illumination occurs with blue regions being towards the bottom and red regions being towards the top. At any instant, an interface exists such that all segments above the interface are red and all segments below the interface are blue. For the purposes of illustration, shaded segments 1002-1004 represent hot red segments with the remainder 1005-1011 representing blue cold segments. Thus, this illustration represents a condition where the water is relatively cold.

Figure 11 Further features of the third indicator of Figure 10 are shown in Figure

11. In a preferred embodiment, the set of light emitting devices of third indicator 1001 is configured to emit light of a third colour. The drawing of heated water from the tank of water is indicated by an animated display of light emitting devices periodically illuminated to emit light of said third colour. In this present example, the third colour is yellow. In this way, it is possible for the third indicator 1001 to indicate that heated liquid is being pumped from a solar collector.

For example, in an animated cycle, segment 1101 , between segments 1010 and 1011 is illuminated for a predetermined duration. Subsequently, segment 1102, between segments 1010 and 1009 is illuminated for a predetermined duration. In this pattern, segments 1103-1109 are illuminated, as indicated by arrow 1110. Segments 1101-1109 are arranged in a linear fashion, with segment 1101 being at the bottom and segment 1109 being at the top. Following illumination of top segment 1109, the sequence is repeatable starting with bottom segment 1101.

Thus, it is possible to see from the third indicator when energy is being generated such that this could possibly identify a time when it would be

preferable to draw hot water. Similarly, if a static display is seen, it will be appreciated that any further heat supplied to the water tank will be derived from an external source and therefore the pulling of water could be discouraged. In an example of display apparatus, if a technical fault is detected, all light emitting devices of an indicator are turned off or otherwise not illuminated. Thus, the user is alerted to a problem occurring within the system.

Figure 12 Figure 12 shows the environment of Figure 1 again, but at a different time of the day. User 103 of a power system is taking a glance at energy display devices 101 , 102 prior to leaving the room through door 104.

It is to be appreciated that the display apparatus provides visible indicators that are configured to change in real time. The indicators change dynamically throughout the day, as the sun comes in or out and consumption demands vary. In addition, by giving greater emphasis to lower levels and lesser emphasis to higher levels, the user can more easily see the difference that lower levels of energy/power consumption/generation make to the overall sum of energy/power consumption and energy/power generation. In this way, the user can recognise intuitively what is a normal presentation of each indicator display at different times of the day. For example, the user may use certain appliances only at particular times of the day, or even only in particular types of weather. The display apparatus thus provides displays for indicating levels relating to a power system that are easy to use and understand, and hence enable the user to become quickly familiar with the operation of their power system.