GB2434207A

GB2434207A - Water and energy cost monitor for domestic appliances

Info

Publication number: GB2434207A
Application number: GB0600578A
Authority: GB
Inventors: David John Marchant
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-01-12
Filing date: 2006-01-12
Publication date: 2007-07-18
Also published as: GB0600578D0

Abstract

A water and energy cost monitor that can measure in real time, the actual running cost of, say a domestic shower, or mixer tap or just a hot water tap in cost per unit time. Variations in flow rate and temperature can thus be changed with direct visual output to the user as to their efficacy, whilst giving the user the best settings for comfort and economy. Temperature sensors 4, 5 and 6 measure inlet hot, cold and mixed water respectively whilst the flow rate sensor 7 measures the mixed water flow rate. A display 13, whether in a remote unit 12 or built into the appliance (figure 2,13) shows the output being monitored. The display shows in real time combined energy and water consumption costs in units of cost/time within a domestic appliance environment.

Description

1 2434207

WATER AND ENERGY COST MONITOR FOR DOMESTIC APPLIANCES

This invention relates to energy and water monitoring devices primarily for domestic appliances.

With the cost of fuel escalating and water becoming metered and in some cases more scarce it is more important to understand and monitor these costs.

Hot water taps often have to be run for many seconds for the stagnant cold water to be run out of the pipes, prior to the hot water flowing. What is often forgotten is that the boiler will probably have had to heat the total amount of water, including the cold run off water to that final running temperature.

Specifically this invention is intended to monitor, in real time, the actual running cost of, say a domestic shower, or mixer tap or just a hot water tap in cost per unit time. Variations in flow rate and temperature can be changed with direct visual output to the user as to their efficacy, whilst giving the user the best settings for comfort and economy. Whilst it is likely that the device will be run via electronics, it can also display other values such as total cost of energy and water used in the opening and closing of the hot tap in the example above taking into account the wasted initial stagnant cold water.

The device measures parameters of water flow rate and inlet temperatures of both cold and hot water. Ideally, the device uses non-invasive sensors, to measure water flow and temperature for concerns over limestone type scaling effects. However in-line flow meters and other temperature sensing means could also be used if this were not a problem. Either system should provide an output that is quite accurate and certainly effective for its application's requirement.

Other parameters will need to be pre-programmed, say on an annual basis, such as water cost in costlm3 and the cost of heating that water whether it is by gas, electricity, oil or other fuel.

Knowing this information, the electronics through simple known integration techniques, will be able to analyse and output the current running cost in real time. The device will visually indicate the running cost in cost /time: e.g. /min, $/Hr. This may be via a standard analogue dial or via a digital display e.g. LED/LCD Accordingly this invention provides a visual display in real time of total energy and water costs in units of cost/time.

Preferably the device is located close to the user and water flow and temperature controls where feedback can be gained via adjustment of these controls. The device may be incorporated into the domestic appliance, in which case it maybe wired directly to the temperature and water flow sensors. Or it may be a standalone display unit powered by batteries and taking its inputs of flow and temperature via a wireless e.g. RF or Infra Red connection. Both methods use known technologies.

As with most electronic appliances it is most useful to have buttons that can select between various options, for output and for for input or programming options. Some of the options are listed below.

Generally the user requires just the total cost of both energy and water combined. However, the device can easily be programmed to output individual readings of say energy alone or water costs alone.

Were this appliance to be used in a bathroom, shower room or high humid environment then it may have to be designed against water ingress in the usual way such as with gaskets or via potting the electronics to prevent moisture ingress.

The visual displays can be of digital or analogue, or of a plurality of one or the other or both types.

The visual display may also give output temperature or volumetric flow rate as further options.

The display could be a simply digital numeric, or a combination of alphanumeric digits or an LCD or TFT display or even some form of analogue output via the digital screen. Alternatively, it could have a standard analogue moving dial to indicate one or many of the options.

The electronics and output display may be powered by batteries or mains or transformed from mains power to a lower safe voltage to be used in the humid environments. It may be powered from an alternative method such as a turbine within the water flow.

Electronic displays such as TFT's and LED's do consume considerably higher currents than passive LCD's and as such may require to go into a sleep mode to save on power consumption, wnen not being used. In this case the device could be timed to sleep after a period of time of zero water flow rate.

Electronic controllers have the ability to retain memory and status and thus may incorporate other timing, averaging or monitoring functions for part or all of the life of the device.

It is often required to have a timer or clock near the appliance -for example in the shower room.

This can easily be accomplished via the electronics and a clock could be set as the default display if needed, such that when the key feature of energy cost is required a touch of a button switches to that mode.

Similarly a programmable timer could be included to indicate to the user the length of time that the appliance is on. It could also be operated automatically when the appliance is initially turned on and fmally gives output readings on shutting down of: total costs, water usage, and time on. The timer could be set as a manual operation and may include a buzzer, or other indicator e.g. simply as a 5 minute timer.

When referring to buttons within the description above, a physical sensor pad or optical or other may be used in its place to control the device.

The device may be preset with parameters such as energy and water costs in the factory or it may allow user interface for these and other functions via buttons and the display. Since there will be a difference in efficiencies and costs between fuel sources, boilers, converters, electricity and the home environment, these will have to be taken into account at the programming or setup stage.

The supplier of the device may give local or national cost updates via a website or suggest how the user may interpret the costs from utility bills, which are sometimes complicated to understand.

The device could be fully integrated into a home network and take output (or usage) data automatically or could be given input data or parameters such as energy and water costs in real time. It could be linked to the outside world via the internet to automatically select the correct parameters or software/firmware upgrades.

The preference for the design is to be non invasive, particularly where there is a likelihood or scale build up with the water pipes. The flow meter could be of a turbine or similar type within the flow to give rotational speed proportional to flow rate and using a known technology such as the hail effect to output the rotational speed electronically. There are other methods of measuring flow both invasive and non invasive to the flow that could be used giving electronic, mechanical or other types of output.

The measurement of water temperature is preferably measured using a thermocouple or similar giving an analogue electrical output that can be used with a small amount of conversion by the electronics. Nonetheless, there are other methods of measuring temperature, for example mercury-in-glass, and these could be converted to electrical output for integration with the flow rate. Alternatively, pure mechanical flow rate output and mechanical temperature output could be integrated mechanically to give a non electronic output probably as an analogue reading.

Depending upon where the flow monitoring is performed and temperature sensors are placed will give different options for performance calculations -this has to be determined by the overall piping arrangement. A minimum requirement is for one flow sensor and three temperature sensors, providing that the temperature sensors measure the hot, cold and mixed water flows.

The flow sensor could therefore be placed in one of three positions. For scale build up, the flow sensor would be best placed in the cold flow side, however if the flow rate of cold were reduced to zero (as sometimes happens if hot water temperature is running low) then there would be no flow measurement. Similarly the flow sensor could be placed in the hot water flow, but as before if that flow is restricted to zero the total water flow rate cannot be interpreted. Hence the ideal place for the flow rate sensor is on the mixed water side which will always measure the total water flow rate.

Other arrangements with further flow sensors could be used, for example one sensor in the hot water flow and one in the cold water flow. Similarly the positions of the temperature sensors could be placed further upstream of the device for higher accuracies but with a longer reaction or stabilisation time perhaps.

It is assumed in these heat calculations that the cold water temperature is the same as the pre-boiler cold water temperature. Variations may happen if there were feeder tanks for both hot and cold water supplies. Sometimes these feeder tanks may vary in temperature depending upon the ambient surrounding temperature and the water usage from them.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which: FIGURE 1 shows a schematic of the temperature mixer and flow control system, having two water supplies (hot and cold) and an output of mixed water.

FIGURE 2 shows a front view of the device integrated into a domestic electric shower module FIGURE 3 shows an embodiment of the whole system described in detail below including a standalone device connected closely to a mixer and flow control valves.

FIGURE 4 shows monitor display panel options As shown in Figure 1, the following equations apply, given that F is the water flow rate in m3/s: with Temperature T in C: Fh is hot water supply flow rate and Th being the hot water pipe temperature F is cold water supply flow rate and I being the cold water pipe temperature Fm is output mixed flow rate and Tm being the mixed water pipe temperature Assume flow rates are stable: Fh + F = Fm Using the steady state Heat flow equation (with s and p being the Specific Heat Capacity and density of water; both assumed to be near constant at these temperatures) s.p.Fh.Th + = s.p.F.Tm or Fh Th + F. T = Fm. Tm Knowing the three water temperatures: Th T Tm and mixed flow rate of Fm the hot water flow rate can be calculated as: Fh = Fm (Tm -Tc)/(Th -T) And thence the Energy flow rate or power Q can be calculated assuming that the boiler has raised the water temperature from T to Th as: Q = F, . (Th -T) . s. p measured in J/s or W QFm (TmTc).S.p Figure 2 simply shows an embodiment of one type of fully integrated installation. It shows a front view often called the control panel 22, of a standard electric shower. The Energy Water Monitor display is shown integrated into the top section with a display 13, some programming buttons 14 and 15 and a mode selection button 16. The standard shower controls being the on-off switch 20, the power light 21, the shower temperature control via a slider valve controlled by a slider button 18 and a similar outlet water flow rate control valve slider button 19.

Figure 3 shows one example of how this device could work using known technology described in detail. Whereas fig 2 showed the device integrated into a standard electric shower unit, figure 3 shows an alternative standalone device connected closely to a mixer and flow control valves.

The standalone monitoring unit 12, comprises a display 13, in this case showing an LED/LCD alphanumeric output giving two lines of text. There are programming buttons 14 and 15 as well as a mode or selection button 16. Internally, but not shown are the electronics, such as a programmable microcontroller, a printed circuit board connected to the display 13 and the mounting for the buttons, 14,15 and 16. The power is supplied via batteries, not shown, (although this could easily have had an external power supply).

The programmable microcontroller has memory and timer capability as well as its own central processing unit for calculating actual and total flow rates and various energy and water cost rates. Input data for energy and water costs, time etc are inputted via the buttons 14, 15 and 16 in a standard way used in many electronic devices.

This monitoring unit is designed for the environment that it will be exposed to. In the case of the shower then all of the joints, buttons, display area, battery doors and other grommets and sealed from water and humidity ingress.

The hot water is supplied to the unit via inlet pipe 1, having passed through a check valve 10; similarly the cold water supply is via inlet pipe 2 having passed through a check valve 11. The check valves stop the hot or cold water running the wrong way back through the supply system once main control valves are shut through differences in static pressures.

The hot and cold water is mixed via a valve 8, and delivered via an outlet pipe 3. Within this pipe 3, there is a water control valve 9, which controls the outlet flow rate to the shower head 17.

Water temperature sensors 4 and 5 are located around the hot and cold supply pipes 1 and 2 respectively. In this case they are thermocouples attached to the metal water pipes in good thermal contact and thus reproduce almost immediate change to the water temperature changes due to the high conductivity of metal. Similarly the output water temperature sensor 6, a thermocouple is attached to the outlet pipe 3 in the same way.

Water flow rate measurement is performed via a turbine 7 in the outlet pipe 3.

It can be clearly seen that the monitoring unit is connected to the shower unit via the three temperature sensors 4, 5 and 6 and the total water flow rate sensor 7; this gives all the information that is required to perform the calculation.

Figure 4 shows some of the display options available for the device. Each display could be selected by simply pressing one of the buttons 14 or 15 and cycling through the variants. When an option is required to be changed then the select button 16 is pressed, hence giving further options for programming.

Display option a) represents costlminute with the reading showing 2.16 cents per minute -using an American currency setup. Option b) represents the actual time showing 7:15 am and option c) represents a minute timer, perhaps having started at 5 minutes and counting down, currently displaying the time of 4 minutes 15 seconds and decrementing per second and when reaching zero will flash and br a buzzer may sound briefly. tAIMS

Claims

1. A device that provides a visual display in real time of combined

energy and water consumption costs in units of cost/time within a domestic appliance environment.

2. A device as claimed in Claim 1 where the display monitors individual costs rates of water or energy in units of cost/time.

3. A device as claimed in Claim 1 where the display monitors the total combined energy and water costs in units of cost over the period of one operation of the appliance from a water flow being turned on to the water being turned off 4. A device as claimed in Claim 3 where the display monitors the total individual energy and water costs in units of cost, the display showing either total water cost or total energy cost for that operation.

5. A device as claimed in any proceeding claim where the visual display is located close to the user and water flow and temperature controls where feedback can be gained via adjustment of these controls.

6. A device as claimed in any proceeding claim where the unit may be programmed for the cost parameters of water and energy rates at the factory, in installation or in situ as and when either or both rates change or the efficiencies of the household system change such as a boiler upgrade.

7. A device as claimed in any proceeding claim where the unit can withstand the environmental conditions of high humidity, high temperature and water spray ingress expected within that domestic appliances environment.

8. A device as claimed in any proceeding claim where the unit can also display parameters measured such as the output and input temperatures or water flow rates.

9. A device as claimed in any proceeding claim where the output is digital or analogue, or of a plurality of one or the other or both types.

10. A device as claimed in any proceeding claim where the power to run the device may come from batteries or mains or transformed from mains power to a lower safe voltage.

11. A device as claimed in any proceeding claim where the power to run the device may come from an alternative method such as a turbine within the water flow.

12. A device as claimed in any proceeding claim where the device is incorporated into the domestic appliance and has connections to the water flow internally 13. A device as claimed in any proceeding claim where the device is remote to the domestic appliance and is connected via wires or wirelessly to the domestic appliance using RF or IR or other technologies as appropriate 14. A device as claimed in any proceeding claim that has an electronic programmer that allows the display to sleep or to stay in a low power mode when not being used that can be woken by pressing a button or similar 15. A device as claimed in any proceeding claim that has an electronic programmer that allows results to be displayed averaged over time whether per discrete period or as an averaged moving total or other method.

16. A device as claimed in any proceeding claim that has an electronic programmer that provides a timer function that can be used as a clock display or as a minute timer with or without an audible signal or to give the timed length of usage of that domestic appliance.

17. A device as claimed in any proceeding claim that has programming or selection buttons or physical sensor pads or optical or other methods to input data or options.

18. A device as claimed in any proceeding claim that is attached physically or remotely to a network in order to have its input programming data such as water and energy costs entered automatically or its output data such as usage used for external analysis.

19. A device as claimed in any proceeding claim that uses a combination of temperature and flow sensors to provide the output of energy and water costs per time in domestic appliances 20. A device as claimed in any proceeding claim that uses water flow sensors that are either invasive or non invasive in the water flow paths.

21. A device as claimed in any proceeding claim that uses temperature sensors that are either invasive or non invasive in the water flow paths.

22. A device as claimed in any proceeding claim that uses temperature sensors that are positioned further upstream or downstream of the domestic appliance in order to give better readings of ambient or heated water whether before or after feeder or storage tanks.

23. A device as claimed in any proceeding claim that uses one or more water flow sensors that are positioned further upstream or downstream of the domestic appliance in order to give better readings of either hot, cold or mixed flow rates 24. A device as claimed in any proceeding claim which is made from metal, plastics material, ceramic, glass, rubber or wood or from a combination of these materials.

25. A water and energy cost monitor for domestic appliances substantially as herein described above and illustrated in the accompanying drawings.