Integrated system for heating water

Abstract

One variation of a method includes, during a first time period preceding a predicted hot water consumption event within a building: triggering a heat pump arranged within a water heater to heat water toward a target supply temperature for water supplied to a building by the water heater; and, at the water heater, supplying water, proximal the target supply temperature, to the building during the hot water consumption event. This variation of the method also includes, during a predicted null hot water consumption window within the building: triggering the heat pump to maintain water stored in the water tank proximal a nominal temperature less than the target supply temperature; and, at the water heater, in response to detecting flow of water from the water heater, triggering an inline heater, arranged within the water heater, to heat water toward the target supply temperature.

I claim: 
     
         1 . A method comprising:
 during a first time period:
 predicting a first estimated time until a first hot water consumption event within a building; 
 accessing a first water temperature of water stored in a water tank of a water heater supplying hot water to the building; 
 accessing a target supply temperature for water supplied to the building by the water heater; 
 estimating a first heating duration to heat water stored in the water tank to the target supply temperature based on a first difference between the first water temperature and the target supply temperature; 
 in response to the first estimated time approaching the first heating duration, triggering a heat pump, arranged within the water heater, to heat water stored in the water tank toward the target supply temperature; and 
 at the water heater, supplying hot water, proximal the target supply temperature and stored in the water tank, to the building during the first hot water consumption event; and 
   during a second time period:
 predicting a second null hot water consumption window within the building; and 
 during the second null hot water consumption window:
 triggering the heat pump to maintain water stored in the water tank proximal a nominal temperature less than the target supply temperature; and 
 at the water heater, in response to flow of water from the water heater:
 triggering an inline heater, interposed between the water tank and an outlet of the water heater, to heat water exiting the water tank toward the target supply temperature. 
 
 
   
     
     
         2 . The method of  claim 1 , further comprising, during a third time period:
 predicting a third estimated time until a third hot water consumption event within the building;   accessing a third water temperature of water stored in the water tank;   accessing a target holding temperature, exceeding the target supply temperature, for maintaining water stored within the water tank;   estimating a third heating duration to heat water stored in the water tank to the target holding temperature based on a third difference between the third water temperature and the target holding temperature;   in response to the third estimated time approaching the third heating duration, triggering the heat pump to heat water stored in the water tank toward the target holding temperature; and   at a mixing valve arranged within the water heater, in response to flow of water from the water heater during the third hot water consumption event:
 combining cold water with hot water, exiting the water tank proximal the target holding temperature, to cool water exiting the water heater to the target supply temperature. 
   
     
     
         3 . The method of  claim 1 , further comprising:
 during an initial time period preceding the first hot water consumption event:
 at a first time during the initial time period:
 triggering a recirculation pump arranged within the water heater to:
 draw cooled water from the building to the water tank; and 
 supply water, proximal the target supply temperature, to the building; 
 
 
 at a second time, following the first time, during the initial time period:
 detecting a second water temperature of water, drawn to the water tank by the recirculation pump, proximal the target supply temperature; and 
 deriving a recirculation duration for the recirculation pump to purge cooled water from the building based on a difference between the first time and the second time; 
 
 triggering the recirculation pump to purge cooled water from the building during the recirculation duration to supply water, proximal the target supply temperature, to the building prior to the first hot water consumption event; and 
 deactivating the recirculation pump. 
   
     
     
         4 . The method of  claim 1 , further comprising, during a third time period:
 predicting a third hot water consumption event within the building and a third hot water consumption volume during the third hot water consumption event;   in response to the third hot water consumption volume falling below a threshold volume, setting a target holding temperature, less than the target supply temperature, for the heat pump to maintain water stored in the water tank during a third null hot water consumption window preceding the third hot water consumption event; and   during the third hot water consumption event:
 at the water heater, in response to flow of water from the water heater:
 triggering the inline heater to heat water exiting the water tank toward the target supply temperature. 
 
   
     
     
         5 . The method of  claim 1 , further comprising, during a third time period:
 predicting a third estimated time until a third hot water consumption event within the building;   accessing a third water temperature of water stored in the water tank;   accessing a sterilization hold duration for maintaining water stored in the water tank at a sterilization temperature greater than the target supply temperature;   estimating a third heating duration to heat water stored in the water tank to the sterilization temperature based on a third difference between the third water temperature and the sterilization temperature; and   scheduling activation of the heat pump to heat water stored in the water tank to the sterilization temperature prior to the third hot water consumption event by at least the sterilization hold duration and the third heating duration.   
     
     
         6 . The method of  claim 5 , further comprising, during the third time period:
 in response to the third estimated time approaching the third heating duration, triggering the heat pump to heat water stored in the water tank toward the sterilization temperature; and   at a mixing valve arranged within the water heater, in response to flow of water from the water heater during the third heating duration:
 combining cold water with hot water, exiting the water tank proximal the sterilization temperature, to cool water exiting the water heater to the target supply temperature. 
   
     
     
         7 . The method of  claim 1 , further comprising, during a third time period:
 predicting a third null hot water consumption window within the building; and   during the third null hot water consumption window:
 triggering a shutoff valve, arranged upstream of the water tank, to close to interrupt flow of cold water from the building to the water tank; 
 detecting a first water pressure in a first hot water supply line within the building at a first time during the third null hot water consumption window; 
 detecting a second water pressure within the first hot water supply line at a second time during the third null hot water consumption window; 
 in response to the second water pressure falling below the first water pressure, interpreting a water leak within the first hot water supply line; and 
 in response to interpreting the water leak:
 generating an alert indicating the water leak within the building; and 
 serving the alert to a user. 
 
   
     
     
         8 . The method of  claim 1 , further comprising, during the first hot water consumption event:
 at a first time, accessing a second water temperature of water stored in the water tank;   in response to the second water temperature falling below the target supply temperature by greater than a second difference:
 triggering a set of resistive heaters, arranged within the water tank, to heat water stored in the water tank toward the target supply temperature; 
   at a second time succeeding the first time, accessing a third water temperature of water stored in the water tank; and   in response to the third water temperature falling below the target supply temperature by greater than a third difference:
 triggering the inline heater to heat water exiting the water tank toward the target supply temperature. 
   
     
     
         9 . The method of  claim 1 , further comprising, during a third time period:
 predicting a third estimated time until a third hot water consumption event within the building;   accessing a third water temperature of water stored in the water tank;   accessing a third air temperature of ambient air proximal the water heater;   in response to the third air temperature falling below a minimum heat pump operating temperature, estimating a third heating duration to heat water stored in the water tank via a set of resistive heaters, arranged within the water heater, based on a third difference between the third water temperature and the target supply temperature;   in response to the third estimated time approaching the third heating duration, triggering the set of resistive heaters to heat water stored in the water tank toward the target supply temperature; and   at the water heater, supplying hot water, proximal the target supply temperature and stored in the water tank, to the building during the third hot water consumption event.   
     
     
         10 . The method of  claim 1 :
 wherein predicting the first estimated time until the first hot water consumption event comprises:
 accessing a set of historical flow rate data representing flow rates of water from the water heater to the building; 
 calculating an average hot water consumption volume during historical time windows coinciding with the first hot water consumption event based on the set of historical flow rate data; and 
 predicting the first estimated time until the first hot water consumption event at a first fixture, in a set of fixtures located within the building, based on the average hot water consumption volume; and 
   further comprising:
 during an initial time period preceding the first hot water consumption event:
 triggering a recirculation valve fluidly coupled to the first fixture to open; and 
 triggering a recirculation pump arranged within the water heater to supply water, proximal the target supply temperature, to the first fixture; and 
 
 during the second null hot water consumption window:
 triggering the recirculation valve to close; and 
 deactivating the recirculation pump. 
 
   
     
     
         11 . The method of  claim 1 :
 further comprising:
 a set of historical flow rate data representing flow rates of water from the water heater to the building during an initial time period preceding the first time period; and 
 generating a set of demand templates based on the set of historical flow rate data, each demand template representing water consumption within the building during a time window; and 
   wherein predicting the first estimated time until the first hot water consumption event comprises:
 accessing a first set of current flow rate data representing flow rates of water from the water heater to the building during a current time window preceding the first hot water consumption event; 
 a first demand template, in the set of demand templates:
 representing a first set of historical flow rate data corresponding to the first set of current flow rate data; and 
 representing a historical time window corresponding to the current time window; and 
 
 predicting the first hot water consumption event based on the first demand template representing water consumption coinciding with the first hot water consumption event. 
   
     
     
         12 . The method of  claim 1 , further comprising:
 detecting flow of water from the water heater during the second null hot water consumption window;   in response to detecting flow of water from the water heater during the second null hot water consumption window, generating a prediction for a third hot water consumption event within the building;   triggering the heat pump to heat water stored in the water tank toward the target supply temperature during a third heating duration preceding the third hot water consumption event; and   at the water heater, supplying hot water, proximal the target supply temperature and stored in the water tank, to the building during the third hot water consumption event.   
     
     
         13 . The method of  claim 1 , further comprising, during a third time period:
 predicting a third null hot water consumption window within the building; and   during the third null hot water consumption window:
 accessing a forecast outdoor air temperature proximal the building; and 
 in response to the forecast outdoor air temperature falling below a freeze-risk temperature:
 triggering a set of valves, arranged downstream the water tank, to open; and 
 activating a recirculation pump arranged within the water heater to circulate heated water between the set of valves and the water tank. 
 
   
     
     
         14 . The method of  claim 1 :
 wherein predicting the first estimated time until the first hot water consumption event comprises:
 accessing a set of historical flow rate data representing flow rates of water from the water heater to the building; 
 calculating an average hot water consumption volume during historical time windows coinciding with the first hot water consumption event based on the set of historical flow rate data; and 
 response to the average hot water consumption volume exceeding a threshold volume, predicting the first hot water consumption event; and 
   wherein triggering the heat pump to heat water stored in the water tank toward the target supply temperature during the first time period comprises:
 triggering the heat pump to heat water stored in the water tank prior to the first hot water consumption event by at least the first heating duration. 
   
     
     
         15 . A method comprising:
 during a first time period:
 predicting a first estimated time until a first hot water consumption event within a building; 
 accessing a first water temperature of water stored in a water tank of a water heater supplying hot water to the building; 
 a target supply temperature for water supplied to the building by the water heater; 
 accessing a target holding temperature, exceeding the target supply temperature, for maintaining water stored within the water tank; 
 estimating a first heating duration to heat water stored in the water tank to the target holding temperature based on a first difference between the first water temperature and the target holding temperature; 
 in response to the first estimated time approaching the first heating duration, triggering a heat pump, arranged within the water heater, to heat water stored in the water tank toward the target holding temperature; and 
 at a mixing valve arranged within the water heater:
 in response to flow of water from the water heater during the first hot water consumption event:
 combining cold water with hot water, exiting the water tank proximal the target holding temperature, to cool water exiting the water heater toward the target supply temperature; and 
 
 
   during a second time period:
 predicting a second null hot water consumption window within the building; and 
 during the second null hot water consumption window:
 triggering the heat pump to maintain water stored in the water tank proximal a nominal temperature less than the target supply temperature; and 
 at the water heater, in response to flow of water from the water heater:
 triggering an inline heater, interposed between the water tank and an outlet of the water heater, to heat water exiting the water tank toward the target supply temperature. 
 
 
   
     
     
         16 . The method of  claim 15 , further comprising, during a third time period:
 predicting a third hot water consumption event within the building;   estimating a third heating duration to heat water stored in the water tank to the target holding temperature;   accessing a set of forecast electrical grid metrics representing forecast energy supply within an electrical grid supplying electrical energy to the water heater;   detecting a time window of excess energy supply, preceding the third hot water consumption event by more than the third heating duration, in the set of forecast electrical grid metrics; and   in response to detecting the time window of excess energy supply, scheduling activation of the heat pump and a set of resistive heaters, arranged within the water heater, to heat water stored in the water tank to the target holding temperature during the time window.   
     
     
         17 . The method of  claim 15 :
 wherein estimating the first heating duration comprises estimating a fixed target heating duration to heat water stored in the water tank to the target supply temperature; and   further comprising:
 accessing a first air temperature of air supplied to the heat pump; 
 calculating a minimum water temperature for water stored in the water tank based on a function relating:
 the fixed target heating duration; 
 the target holding temperature; 
 a total volume of the water tank; and 
 the first air temperature; and 
 
 during an initial time period preceding the first hot water consumption event by more than first heating duration:
 triggering the heat pump to maintain water in the water tank proximal the minimum water temperature. 
 
   
     
     
         18 . The method of  claim 15 :
 further comprising, during the first time period:
 accessing a first air temperature of air supplied to the heat pump; and 
   wherein estimating the first heating duration to heat water stored in the water tank to the target holding temperature comprises:
 estimating the first heating duration to heat water stored in the water tank to the target holding temperature based on a function relating:
 the first difference between the first water temperature and the target holding temperature; 
 a total volume of the water tank; and 
 the first air temperature. 
 
   
     
     
         19 . The method of  claim 15 , further comprising:
 during the first time period:
 predicting a first hot water consumption volume during the first hot water consumption event; and 
 in response to the first hot water consumption volume falling below a total volume of the water tank, setting the target holding temperature at the target supply temperature; and 
   during a third time period:
 predicting a third hot water consumption event within the building and a third hot water consumption volume during the third hot water consumption event; and 
 in response to the third hot water consumption volume exceeding the total volume of the water tank, setting the target holding temperature exceeding the target supply temperature proportional a volume difference between the total volume of the water tank and the third hot water consumption volume. 
   
     
     
         20 . A method comprising:
 during a first time period:
 predicting a first hot water consumption event within a building; 
 accessing a target supply temperature for water supplied to a building by a water heater; 
 triggering a heating element arranged within the water heater to heat water, stored in a water tank of the water heater, toward the target supply temperature during a first heating duration preceding the first hot water consumption event; and 
 at the water heater, supplying hot water, proximal the target supply temperature and stored in the water tank, to the building during the first hot water consumption event; and 
   during a second time period:
 predicting a second null hot water consumption window within the building; and 
 during the second null hot water consumption window:
 triggering the heating element to maintain water stored in the water tank proximal a holding temperature less than the target supply temperature; and 
 at the water heater, in response to detecting flow of water from the water heater:
 triggering an inline heater, arranged within the water heater, to heat water exiting the water tank toward the target supply temperature.