Patent Application
20120143539
The present invention relates to a device that measures the amount of electricity consumed by an appliance and, based on the source of the electricity, calculates and displays the amount of carbon dioxide that was emitted into the atmosphere as a result of producing that amount of electricity.
Electricity is generated in many different ways, with a wide variation in environmental impact. When electricity is generated through the burning of fossil fuels such as oil, natural gas, or coal, carbon dioxide is released into the atmosphere. Carbon dioxide, along with methane, nitrous oxide, and fluorinated gases, are called “greenhouse gases” and are associated with a number of adverse environmental effects, including global warming, unhealthy air quality, and acid rain. These adverse effects are not associated with energy derived from solar, wind, or geothermal sources.
In view of the heightened awareness of the damage done to the environment as a result of the use of fossil fuels, the public has become more interested in the ways to reduce the emission of greenhouse gases. If people know the amount of destructive carbon that was emitted by the generation of the electricity needed to power their household appliances, they can make the decisions on which appliances to use, how often to use them, and whether to replace them with other appliances that have less of an adverse environmental impact.
There are a number of software programs that estimate a “carbon footprint,” i.e., the measure of the impact human activities have on the environment in terms of the amount of greenhouse gases produced, measured in units of carbon dioxide. See, e.g., www.carboncounter.org; www.carbonfootprint.com; and www.begreennow.com. These calculators factor in elements that characterize lifestyles, such as house size, type of car, miles traveled by air or road, to arrive at a number for a carbon footprint which depicts the relative impact on the environment such a lifestyle represents. These carbon footprints, while interesting, are merely approximations based on broad assumptions which may or may not hold true for any one individual or household.
Energy monitors for household appliances are known in the art. For example, U.S. Pat. No. 6,095,850 discloses an electric adapter that displays various parameters of the electricity consumed by an appliance that has been plugged into the adapter. Also, U.S. Pat. No. 6,476,729 discloses a power monitoring module with a display unit which is placed on a power strip to display the power used by the appliances plugged into the strip.
The prior art, however, does not reveal a device which can accurately indicate to a consumer, based on the source of electricity, how much carbon was emitted in the production of the electricity needed to run a particular appliance. Further, there is no disclosure of a device that can display the aggregate electricity consumption of multiple appliances.
The present invention is directed to an energy monitor which can display various electrical parameters of one or more appliances. Included among the parameters that may be displayed is an accurate reading of the amount of carbon that was emitted by the generation of the electricity used by the appliances.
The energy monitor senses the amount of electricity that is drawn by an appliance and derives the number of watts being used by the appliance. A time base signal generator in the device measures the time during which the watts are being drawn to arrive at the number of kilowatt-hours used by the appliance. The number of kilowatt-hours are multiplied by the carbon dioxide emission rate for the specific power source from which the electricity is obtained to arrive at the weight of carbon dioxide that was released into the atmosphere by the generation of that amount of electricity.
Generating electricity from fossil fuels such as coal, petroleum, and gas results in the emission of carbon dioxide into the atmosphere, while electricity generated from nuclear, wind, geothermal, or solar sources does not. Power utility companies in different parts of the United States use different fuel mixes to obtain electricity to supply to its customers. The Environmental Protection Agency lists the percentages of the fuel mix components, i.e., “power profiles,” for different cities on its website, for example:
Carbon dioxide emission rates are calculated based on power profiles from generating units of U.S. electric plants. The carbon emission rate, i.e., pounds of carbon dioxide per kilowatt-hour, in different geographic regions in 1999 have been calculated to be
Data from “Carbon Dioxide Emissions from the Generation of Electric Power in the United States,” July 2000, Department of Energy, Washington D.C. 20585, Environmental Protection Agency, Washington D.C. 20460.
Accordingly, if consumers are interested in having a more accurate measure of the amount of carbon emitted into the atmosphere by their energy use, they will need to program their energy meter with the geographically-appropriate carbon dioxide emission rate. For customers not interested in such accurate numbers, the device may be programmed with the national average as the default.
To use the device, the consumer plugs the appliance into the sensor portion of the meter. The sensor measures the electricity that is used by the appliance and transmits the data to a central processing unit which then sends the results of calculations to a display to indicate the pounds of carbon that were emitted. To enhance the accuracy of the information presented by the device, it may be equipped with an aging icon that can display how old the reading is. Should the consumer see that the icon indicates that the reading is old, the consumer may wait for the refreshed reading to better understand the his or her electricity use.
In one embodiment, the device may be comprised of multiple sensors which can transmit information regarding multiple appliances to the receiver. The receiver can then present the information for each appliance individually or as an aggregate measure of electricity consumed and carbon emitted.
One embodiment of the invention includes a wireless transmission from the sensor to the receiver. A second embodiment utilizes two components, a sensor and a receiver, that are tethered together by wires for the transmission of information. Yet another embodiment is a unit in which the sensor and receiver are integrated within a single housing, which also includes a display.
A circuit block diagram of the circuit of the wireless embodiment of the inventive device is shown in
Current sensing circuit 14 and voltage sensing circuit 15 detect and measure the current and voltage levels of the electricity drawn by the appliance. This technology, including the various circuitry choices and components, is known to those skilled in the art. While the embodiments herein incorporate voltage detecting circuits, other configuration in which a constant voltage is programmed into the unit may also be employed. This type of configuration will be less costly to manufacture but will lower the accuracy of the readings.
In a preferred embodiment, analog-to-digital converter 16 converts the analog current signal passing through current amplifier 18 into a digital signal; analog to digital converter 17 converts the analog voltage signal passing through voltage amplifier 19 into a digital signal. These signals are sent to control circuit 20 which also receives, transmits to, and processes data stored in memory 21 as well as data from time base signal generation circuit 22.
Control circuit 20 wirelessly transmits data relating to the current, voltage, phase angle, power, consumption since last transmission, and accumulated consumption to the control circuit 25 where it is further processed and the resulting data is stored in memory 32.
In setting up the inventive device for use, the user will obtain the carbon dioxide emission rate for the relevant geographic region and program that rate into the device using input unit 30; this data is sent to control circuit 25. Other data, such as cost of electricity per kilowatt-hour, can also be obtained locally and entered into the system using input unit 30. Control circuit 25 processes the data received from control circuit 20 with the data input by the user as well as data received from time base signal generation circuit 31 and memory 32 to calculate, inter alia, a value for the amount of carbon dioxide that was emitted into the atmosphere by the generation of the amount of electricity used by the appliance. Control circuit 25 sends that carbon amount value, as well as other data, to display 33.
The front panel 44 of display 33, shown in
Information relating to electricity drawn by the appliance can be shown on the screen in various configurations, one of which is shown in
The system is continually reading the current and voltage, storing the values in memory 21 and memory 32, while control circuit 20 processes the values and sends data to control circuit 25 which sends processed data to display unit 11. While the display may be configured to show data in real time, in certain instances it may be more cost-effective to display periodic readings. To reflect that the data displayed is not in real time, but rather is being refreshed periodically, display screen 45 may be configured with an aging icon, such as the pie chart icon 79 as shown in
Screen 45 may contain other icons, such as a coal plant icon 76 to indicate carbon emissions, used to clarify or emphasize the type of value on display.
The device may be programmed to display projections of usage based on prior usage. Projections can be shown as the primary value 77 with an indicator 80 showing whether the projection is a daily, weekly, monthly, or yearly forecast.
Data may be sent from a number of different sensors, as shown in
Circuit 201 is arranged on a circuit board inside energy sensor 210 and circuit 202 is arranged on a circuit board within display unit 211. Current sensing circuit 214 and voltage sensing circuit 215 detect and measure the current and operating voltage level, respectively, of the electricity drawn by the appliance.
In this preferred embodiment, analog-to-digital converter 216 converts the analog current signal passing through current amplifier 218 into a digital signal; analog to digital converter 217 converts the analog voltage signal passing through voltage amplifier 219 into a digital signal. These signals are sent to control circuit 220 which, in addition, receives, transmits, and processes data stored in memory 221 as well as data from time base signal generation circuit 222.
Control circuit 220 then sends data relating to the current, voltage, phase angle, power, consumption since last transmission, and accumulated consumption through the circuit to the display 225.
In setting up the inventive device for use, the user will obtain the carbon dioxide emission rate for the relevant geographic region and program that rate into the device using input and selection devices, buttons 271, 272, and 273 shown in
The front panel of display 211, shown in
The system is continually reading the current and voltage, storing the values in memory 221, while control circuit 220 processes the data and sends processed data to display unit 211.
Screen 245 may contain other icons 281 to emphasize the type of value on display, such as a coal image, dollar sign, or electricity symbol.
The device may be programmed to display projections of usage based on prior usage. Projections can be shown as the primary value 277 with a further icon 280 showing whether the projection is a daily, weekly, monthly, or yearly forecast.
In a preferred embodiment, analog-to-digital converter 316 converts the analog current signal passing through current amplifier 318 into a digital signal; analog to digital converter 317 converts the analog voltage signal passing through voltage amplifier 319 into a digital signal. These signals are sent to control circuit 320 which, in addition, receives, transmits, and processes data stored in memory 321 as well as data from time base signal generation circuit 323.
Control circuit 320 then sends data relating to the current, voltage, phase angle, power, consumption since last transmission, and accumulated consumption through the circuit to the display 325.
In setting up the inventive device for use, the user will obtain the carbon dioxide emission rate for the relevant geographic region and program that rate into the device using input and selection devices 371, 372, 373 to input unit 330 which then will be sent to control circuit 320. Other data, such as cost of electricity per kilowatt-hour, can also be obtained locally and entered into the system using input devices 371, 372, 373. Control circuit 320 processes the data received from voltage detecting circuit 314 and current detecting circuit 315 with the data input by the user as well as data received from time base signal generation circuit 323 and memory 321 to calculate, inter alia, a value for the amount of carbon dioxide that was emitted into the atmosphere by the generation of the amount of electricity used by the appliance. Control circuit 320 then sends that carbon amount value to display 325.
Housing 310 includes a screen 345, such as an LED or LCD display, that indicates information such as the cost of electricity consumed, physical data such as voltage, current, kilowatt-hour, carbon emitted, elapsed time, and evaluation period. Buttons 371, 372, and 373 may be configured to cycle the display through different values, e.g., to estimate future costs for different evaluation periods or to change the display to indicate different parameters. Information relating to electricity drawn by the appliance can be shown on the screen in various configurations, such as total weight of carbon emitted, kilowatt-hours, cost, projected use or cost, etc.
The system is continually reading the current and voltage, storing the values in memory 321, while control circuit 325 processes the data and sends processed data to display screen 345. Screen 345 may contain other icons to emphasize the type of value on display, such as a coal image, dollar sign, or electricity symbol.
The device may be programmed to display projections of usage based on prior usage. Projections can be shown as the primary value 377 with other icons showing whether the projection is a daily, weekly, monthly, or yearly forecast.
