Patent Publication Number: US-8522579-B2

Title: Clothes washer demand response with dual wattage or auxiliary heater

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation-in-part application and claims priority from U.S. patent application Ser. No. 12/559,751, filed 15 Sep. 2009, which application is expressly incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     This disclosure relates to energy management, and more particularly to energy management of household consumer appliances. The present disclosure finds particular application to energy management of a clothes washer appliance, and is also referred to as a clothes washer demand response. 
     Currently, utilities charge a flat rate. Increasing costs of fuel prices and high energy use during certain parts of the day make it highly likely that utilities will begin to require customers to pay a higher rate during peak demand. Accordingly, a potential cost savings is available to the homeowner by managing energy use of various household appliances, particularly during the peak demand periods. As is taught in the cross-referenced applications, a controller is configured to receive and process a signal, typically from a utility, indicative of a current cost of supplied energy. The controller is configured to change the operation of an appliance from a normal mode (e.g., when the demand and cost of the energy is lowest) to an energy savings mode (which can be at various levels, e.g., medium, high, critical). Thus, various responses are desired in an effort to reduce energy consumption and the associated cost. 
     More particularly, the parent application noted above generally teaches adjusting operation schedule, an operation delay, an operation adjustment and a select deactivation on at least one or more power consuming features or functions to reduce power consumption of the clothes washer in the energy savings mode. For example, the operation delay may include a delay in start time, an extension of time to a delayed start, pausing an existing cycle, delaying a restart or any combination of these examples. A need exists for providing alternative courses of operation in a peak demand state where a consumer&#39;s flexibility and convenience is maximized during peak pricing events. 
     SUMMARY OF THE DISCLOSURE 
     A clothes washer includes at least one power-consuming feature, including a heater assembly. A controller is adapted to receive and process a signal from a utility indicative of the current cost of supplied energy. The controller operates the clothes washer in one of a plurality of operating modes, including at least a normal mode and an energy savings mode based on the received signal. The controller is configured to change the operation of the heater assembly for a period of time based on input received from the signal. 
     The heater assembly preferably includes a first heater and a second heater, or a dual wattage heater, and in the normal operating mode, only the first heater is used. In another normal operating mode, both of the first and second heaters are used, and in the energy savings mode, only one of the first and second heaters is used. 
     In one arrangement, the first heater has a greater wattage rating than the second heater. 
     In a normal operating mode, a water heating cycle is active for a shorter period of time than in the energy savings mode, and in the normal operating mode, one or both of the first and second heaters are used. 
     In another arrangement, only the lower wattage heater is operated during a water heating cycle in an energy savings mode. 
     A method of operating a clothes washer having a controller that receives and processes a signal from a utility indicative of the current cost of supplied energy includes providing a dual wattage heater assembly and operating the heater assembly at a lower wattage in the energy savings mode. 
     The method further includes extending a first time period of operating the selected cycle in the energy savings mode in comparison to a second time period of operating the selected cycle in the normal mode. 
     The present disclosure reduces the average power used by the clothes washer during peak pricing times, and/or reduces the overall energy used by the clothes washer during peak pricing times. 
     The present arrangement saves on costs, and adds convenience and flexibility for the consumer to deal with pricing events. 
     Still another benefit resides in completing the cycle faster while still shedding electrical load without having to pause or delay the cycle entirely. 
     Selected ones of the solutions are easy to execute, i.e., requiring only software to change the clothes washer operation as a result of received signals. 
     Still other benefits and advantages of this disclosure will become more apparent upon reading and understanding the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of an exemplary demand managed home including appliances such as a clothes washer. 
         FIG. 2  is a perspective view of a clothes washer. 
         FIG. 3  is a flowchart that generally illustrates the logic associated with a demand managed appliance. 
         FIG. 4  is a graphical representation of the instantaneous wattage profile for a typical washing machine cycle incorporating a heater. 
         FIG. 5  is a graphical illustration of use of a dual wattage heater and the associated impact on average energy and total energy used. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a general system diagram  50  of a utility meter  52  that communicates with utility  54  and a controller  56  that receives and processes a signal from the meter. The occurrence of peak demand and demand limit data may be communicated by the utility and through the meter to the controller. The demand limit can be set by the homeowner or consumer in some instances. Additionally, the homeowner can choose to force various modes in the appliance control based on the rate that the utility is charging. The controller may interact with a home router  58 , home PC  60 , broadband modem  62  or the internet  64 . Preferably, the controller  56  is configured to control various items in the home, such as the lighting  66 , one or more appliances  68  (including a clothes washer), the thermostat and HVAC  70 ,  72 , respectively, and may include a user interface  74  that displays information for the homeowner and allows the homeowner to program the controller or override selected functions if so desired. This system is generally shown and described in commonly owned U.S. patent application Ser. No. 12/559,703, filed Sep. 15, 2009. 
     An exemplary embodiment of a demand managed appliance  100  is clothes washer  110  schematically illustrated in  FIG. 2 . The clothes washer  110  comprises at least one power consuming feature/function  102  and a controller  104  operatively associated with the power consuming feature/function. The controller  104  can include a micro computer on a printed circuit board which is programmed to selectively control the energization of the power consuming feature/function. The controller  104  is configured to receive and process a signal  106  indicative of a utility state, for example, availability and/or current cost of supplied energy. The energy signal may be generated by a utility provider, such as a power company, and can be transmitted via a power line, as a radio frequency signal, or by any other means for transmitting a signal when the utility provider desires to reduce demand for its resources. The cost can be indicative of the state of the demand for the utility&#39;s energy, for example a relatively high price or cost of supplied energy is typically associated with a peak demand state or period and a relative low price or cost is typically associated with an off-peak demand state or period. 
     The controller  104  can operate the clothes washer  110  in one of a plurality of operating modes, including a normal operating mode and an energy savings mode, in response to the received signal. Specifically, the clothes washer  110  can be operated in the normal mode in response to a signal indicating an off-peak demand state or period and can be operated in an energy savings mode in response to a signal indicating a peak demand state or period. As will be discussed in greater detail below, the controller  104  is configured to at least selectively adjust and/or disable the power consuming feature/function to reduce power consumption of the clothes washer  110  in the energy savings mode. 
     The clothes washer  110  generally includes an outer case or housing  112  and a control panel or user interface  116 . The clothes washer further includes a lid pivotally mounted in the top wall. Though not shown in the drawings, clothes washer  110  includes within outer case  112 , for example, a tub and/or wash basket  114  disposed for receiving clothes items to be washed, a drive system or motor  118  operatively connected to the controller and the basket  114  to tumble and/or agitate the wash load (also referred to herein as mechanical action) during wash and rinse cycles and spinning the basket during spin cycles, and a liquid distribution system comprising a water valve, for delivering water to the tub and basket and a pump for removing liquid from the tub, all of which may be of conventional design. Controller  104  is configured with a plurality of clothes washing algorithms preprogrammed in the memory to implement user selectable cycles for washing a variety of types and sizes of clothes loads. Each such cycle comprises a combination of pre-wash, wash, rinse, and spin sub-cycles. Each sub-cycle is a power consuming feature/function involving energization of a motor or other power consuming components. The amount of energy consumed by each cycle depends on the nature, number and duration of each of the sub-cycles comprising the cycle. The user interface  116  can include a display  120  and control buttons for enabling the user to make various operational selections. Instructions and selections are typically displayed on the display  120 . The clothes washer further includes a door or lid  126  mounted within a top wall  128 . Clothes washing algorithms can be preprogrammed in the memory accessed by the controller for many different types of cycles. 
     One response to a peak demand state is to delay operation, reschedule operation for a later start time, and/or alter one or more of selected functions/features in order to reduce energy demands. For example, clothes washers have the capacity to run at off-peak hours because demand is either not constant and/or the functions are such that immediate response is not necessary. However, a cost savings associated with reduced energy use during a peak demand period when energy costs are elevated must be evaluated with convenience for the consumer/homeowner. As one illustrative example, the clothes washer  110  that has been loaded during the daytime, i.e., typical peak demand period hours, can be programmed to delay operations for a later, albeit off-peak demand hours. 
     In order to reduce the peak energy consumed by a clothes washer, modifications and/or delays of individual clothes washer cycles can be adjusted in order to reduce the total and/or instantaneous energy consumed. Reducing total and/or instantaneous energy consumed also encompasses reducing the energy consumed at peak times and/or reducing the overall electricity demands during peak times and non-peak times. 
     In conjunction with the scheduling delays described above, or as separate operational changes, the following operation adjustments can be selected in order to reduce energy demands. The operation adjustments to be described hereinafter, can be implemented in conjunction with off-peak mode hours and/or can be implemented during on-peak mode hours. Associated with a clothes washer, the operational adjustments can include one or more of the following: a reduction in operating temperature (i.e. temperature set point adjustments) in one or more cycles, a disablement of one or more heaters in one or more cycles, reduction in power to one or more heaters, a switch from a selected cycle to a reduced power consumption cycle, a reduction in a duration of cycle time in one or more cycles, a disablement of one or more cycles, a skipping of one or more cycles, a reduction of water volume and/or water temperature in one or more cycles, and an adjustment to the wash additives (i.e., detergent, fabric softener, bleach, etc.) in one or more cycles. Illustratively, a switch from a selected cycle to a reduced power consumption cycle could include a change to the cycle definition when a command is received. For example, if a customer/user pushes “heavy duty wash” cycle, the selected cycle would then switch to a “regular” cycle, or the customer/user pushes “normal” cycle which would then switch to a “permanent press” cycle. As described, the switching is in response to lowering the energy demands from a selected cycle to a reduced power consumption cycle that meets a similar functional cycle. 
     With reference to  FIG. 3 , a control method in accordance with the present disclosure comprises communicating with an associated utility and receiving and processing the signal indicative of cost of supplied energy (S 200 ), determining a state for an associated energy supplying utility, such as a cost of supplying energy from the associated utility (S 202 ), the utility state being indicative of at least a peak demand period or an off-peak demand period (S 203 ). The method further includes operating the clothes washer  110  in a normal mode during the off-peak demand period (S 204 ), operating the clothes washer  110  in an energy savings mode during the peak demand period (S 206 ), selectively adjusting any number of one or more power consuming features/functions of the clothes washer to reduce power consumption of the appliance in the energy savings mode (S 208 ), and returning to the normal mode (S 210 ) after the peak demand period is over (S 212 ). 
     It is to be appreciated that a selectable override option can be provided on the user interface  116  providing a user the ability to select which of the one or more power consuming features/functions are adjusted by the controller in the energy savings mode. The user can selectively override adjustments, whether time related or function related, to any of the power consuming functions. The operational adjustments, particularly an energy savings operation can be accompanied by a display on the panel which communicates activation of the energy savings mode. The energy savings mode display can include a display of “ECO”, “Eco”, “EP”, “ER”, “CP”, “CPP”, “DR”, or “PP” or some other representation on the appliance display  120 . In cases with displays having additional characters available, messaging can be enhanced accordingly. 
     Another load management program offered by an energy supplier may use price tiers which the utility manages dynamically to reflect the total cost of energy delivery to its customers. These tiers provide the customer a relative indicator of the price of energy and in one exemplary embodiment are defined as being LOW (level 1), MEDIUM (level 2), HIGH (level 3), and CRITICAL (level 4). In the illustrative embodiments the appliance control response to the LOW and MEDIUM tiers is the same namely the appliance remains in the normal operating mode. Likewise the response to the HIGH and CRITICAL tiers is the same, namely operating the appliance in the energy saving mode. However, it will be appreciated that the controller could be configured to implement a unique operating mode for each tier which provides a desired balance between compromised performance and cost savings/energy savings. If the utility offers more than two rate/cost conditions, different combinations of energy saving control steps may be programmed to provide satisfactory cost savings/performance tradeoff. The operational and functional adjustments described above, and others, can be initiated and/or dependent upon the tiers. For example, the clothes washer  110  hot water selection can be prevented or ‘blocked’ from activating if the pricing tier is at level 3 or 4. The display  120  can include an audible and visual alert of pricing tier  3  and  4 . Some communication line with the utility can be established including, but not limited to, the communication arrangements hereinbefore described. In addition, the display  120  can provide the actual cost of running the appliance in the selected mode of operation, as well as, maintain a running display of the present cost of energy. If the utility offers more than two rate/cost conditions, different combinations of energy saving control steps may be programmed to provide satisfactory cost savings/performance tradeoff. 
     Turning next to  FIGS. 4 and 5 , some clothes washers are provided with a sanitization or sanitizing cycle in which a heater elevates the water temperature in the clothes washer above 140° F., and preferably to approximately 140°-150° F., for an extended time period, e.g., on the order of 30-60 minutes. This is represented in  FIG. 4 , where the instantaneous wattage profile  300  of a wash cycle that includes a sanitizing cycle (also generally referred to as water heating) is illustrated. After a fill and tumble/agitate portion  302  of the wash cycle, the water is then heated and then further tumbled/agitated in the sanitizing portion  304  of the wash cycle where energy use in the exemplary embodiment is on the order of 900-1,200 watts. Once the water heating portion  304  of the wash cycle is complete, a remainder  306  of the wash cycle, i.e., drain, rinse, and spin dry, is completed. 
     As shown in  FIG. 4 , the most energy intensive portion of the wash cycle is associated with the sterilization or sanitization portion  304 . One response in a peak pricing period is to disable the water heating cycle, i.e., not allow the sanitizing portion of the wash cycle to be activated or alternatively delay the wash cycle, although such delay may be on the order of many hours. Although both of these options provide potential cost savings to the user/homeowner, these options are generally viewed as a potential inconvenience. On the other hand, there is an option of allowing the clothes washer to operate in the normal mode, i.e., run the water heating portion of the wash cycle during the peak demand period. As will be appreciated from  FIG. 4 , however, this has the potential to result in a cost increase for the consumer during a peak demand. 
     Two potential solutions simultaneously satisfy a desire to save energy and reduce costs while also limiting the inconvenience to the homeowner. For example, as illustrated in  FIG. 5 , use of a dual wattage heater (a single heater with two different wattages) operated at a reduced wattage level, or a second, low wattage heater (having a lower wattage than the first, primary heater) can result in significant energy savings during operation when compared to the primary heater in the sanitizing portion of the wash cycle. The first heater (or dual wattage heater if no second heater is provided) is schematically represented in  FIG. 2  by reference numeral  140  and the second heater identified as  142 . Instantaneous wattage plot  400  is similar to the profile  300  of  FIG. 4  that shows energy used in a normal mode of operation. Particularly, portion  402  is representative of the energy incurred during the fill and tumble/agitate portions of the wash cycle. Normal water heating in the sanitizing cycle (region  404  of the plot) has instantaneous wattage levels ranging between approximately 950 to approximately 1,200 watts although it will be understood that the particular wattage values may vary from one clothes washer to another and that these wattage ranges are merely representative values. Thereafter, the third portion  406  of the graph of the normal mode of operation is representative of the energy associated with the drain, rinse, and spin dry features of the wash cycle, similar to graph portion  306  in  FIG. 4 . 
     If a dual wattage heater is provided in the clothes washer, or alternatively a second, lower wattage heater  142  is used, then lower wattage heater operation will result in a substantial reduction in instantaneous wattage used during the wash cycle, and particularly during the sanitizing portion of the wash cycle. Thus, plot  410  represents the instantaneous wattage during this energy savings mode of operation that uses the low wattage heater to heat the water. The instantaneous wattage ranges, for example, between 450 and 700 watts as shown in region  412  of the plot  410 . It will also be appreciated that the reduced instantaneous wattage will take longer to heat the water to the desired temperature and thus this portion  412  of the graph, when compared to  404  representative of instantaneous wattage during normal operation with a higher wattage heater, is substantially extended. In this slower heating arrangement the cycle time is longer but there is a slight reduction in the cost and total energy consumption as evident from a comparison of total energy consumption during normal operation represented by plot  416  and the total energy consumption during the energy saving operation using the low wattage heater as represented by plot  418 . 
     It is believed that a dual wattage heater where the first and second wattage ratings are used for the same function (heating of the water), or alternatively use of a second heater having a lower wattage rating than the first heater and again used for the same function (such as heating the water), has not been used in a clothes washers. This is contrasted with a dual wattage heater or use of a second heater for use with a different function, e.g., a steam cycle. The concept of the present disclosure allows a washer cycle to employ a heater for use with a sanitize cycle to be completed without undue delay and while still benefiting the grid and saving the consumer money even if the consumer does not want to wait. Although the cycle time will be longer than compared to the normal mode of operation, the wash cycle will not itself be delayed (inactive) during these critical time periods. Using the lower wattage heater during the costly operation times minimizes the cost impact of running a sanitization cycle if the consumer wants to run the cycle at an expensive time period. The required temperature used in a sanitization cycle can still be achieved and adequately treat various soiled garments or laundry items. 
     In addition, if the DSM signal reduces to a non-high or a non-peak level during the extended heating cycle, the controller  104  can be configured to allow the clothes washer to return to the normal operation mode or could continue with the energy savings mode of operation until the wash cycle is complete 
     The disclosure has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations.