Contemporaneous hybrid heating

Abstract

Contemporaneous hybrid heating may be provided by a heat pump, including: an indoor heat exchanger located in or in communication with the conditioned environment; an outdoor heat exchanger located in or in communication with the outdoor environment, wherein the outdoor heat exchanger is in fluid communication with the indoor heat exchanger via a refrigerant circuit; a fueled heater; and a controller, configured to, when the system is operating in a hybrid heating mode, activate both of the heat pump and the fueled heater at a given time based on an air rise temperature measured across the indoor heat exchanger.

The invention is claimed as follows: 
     
         1 . A system for conditioning air in a conditioned environment inside a structure with an outdoor environment outside the structure being non-conditioned, comprising:
 a heat pump, including:
 an indoor heat exchanger located in or in communication with the conditioned environment; 
 an outdoor heat exchanger located in or in communication with the outdoor environment, wherein the outdoor heat exchanger is in fluid communication with the indoor heat exchanger via a refrigerant circuit; 
   a fueled heater; and   a controller, configured to, when the system is operating in a hybrid heating mode, activate both of the heat pump and the fueled heater at a given time based on an air rise temperature measured across the indoor heat exchanger.   
     
     
         2 . The system of  claim 1 , wherein the indoor heat exchanger and the fueled heater are located in a shared cabinet that is ducted into an airflow path of the conditioned environment. 
     
     
         3 . The system of  claim 1 , wherein the fueled heater further comprises:
 a firewall;   a combustion chamber located on a first side of the firewall;   a vent fan located on the first side of the firewall; and   heat exchange tubing located on a second side of the firewall, opposite to the first side, having a first diameter connected to a gas output of the combustion chamber and a second diameter, less than the first diameter, connected to an intake of the vent fan.   
     
     
         4 . The system of  claim 1 , wherein the fueled heater is connected to a fuel supply that supplies a fuel to the fueled heater for combustion, the fuel including natural gas, propane, hydrogen, fuel oil, or combinations thereof. 
     
     
         5 . The system of  claim 1 , further comprising an electric heater, wherein the controller is further configured to activate the electric heater in place of the fueled heater at the given time when a fuel supply for the fueled heater is below a threshold reserve level or a renewable energy source associated with the electric heater is available at a threshold generation level. 
     
     
         6 . The system of  claim 1 , wherein, when the controller activates both of the heat pump and the fueled heater at the given time, the fueled heater and the heat pump each operate at between 0% and 100% of respective rated outputs. 
     
     
         7 . The system of  claim 5 , wherein the controller is configured to increase an operational rate of the fueled heater when the air rise temperature is below a sufficiency threshold for the heat pump. 
     
     
         8 . The system of  claim 5 , wherein controller is configured to decrease an operational rate of the fueled heater when the air rise temperature is above a sufficiency threshold for the heat pump. 
     
     
         9 . The system of  claim 1 , wherein the controller is configured to adjust a triggering threshold of the air rise temperature to trigger operating both the fueled heater and the heat pump at the given time based on at least one of:
 a cost of fuel for the fueled heater;   a user preference for operating the fueled heater relative to the heat pump;   a temperature in the outdoor environment at the given time;   a forecasted temperature for the outdoor environment at a future time;   a time of day of the given time; or   an amount of fuel available for the fueled heater at the given time.   
     
     
         10 . A method for conditioning air inside a structure, comprising:
 activating, by a controller, a heat pump to heat a conditioned environment inside the structure;   detecting, using a sensor, an air rise temperature across an indoor heat exchanger of the heat pump located in or in communication with the conditioned environment;   determining, using the controller, whether the air rise temperature is below a triggering threshold; and   when the air rise temperature is below the triggering threshold, activating, by the controller, a fueled heater to heat the conditioned environment contemporaneously with the heat pump at a given time.   
     
     
         11 . The method of  claim 10 , further comprising, in response to detecting that the air rise temperature across the indoor heat exchanger is below the triggering threshold:
 decreasing an output of the heat pump.   
     
     
         12 . The method of  claim 11 , further comprising, in response to decreasing the output of the heat pump to 0% of rated output:
 operating only the fueled heater to heat the conditioned environment;   detecting, using the sensor, the air rise temperature across the indoor heat exchanger at a subsequent time to the given time;   determining, using the controller, whether the air rise temperature is above a sufficiency threshold; and   when the air rise temperature is above the sufficiency threshold, activating, by the controller, the heat pump to heat the conditioned environment contemporaneously with the fueled heater.   
     
     
         13 . The method of  claim 10 , further comprising, in response to determining that the air rise temperature across the indoor heat exchanger is above a sufficiency threshold while heating the conditioned environment via both the heat pump and the fueled heater:
 decreasing an output of the fueled heater; and increasing an output of the heat pump.   
     
     
         14 . The method of  claim 10 , further comprising:
 adjusting the triggering threshold of the air rise temperature to trigger operating both the fueled heater and the heat pump contemporaneously based on at least one of:   a cost of fuel for the fueled heater;   a user preference for operating the fueled heater relative to the heat pump;   a temperature in a non-conditioned, outdoor environment outside the structure at the given time;   a forecasted temperature for the outdoor environment at a future time;   a time of day of the given time; or   an amount of fuel available for the fueled heater at the given time.   
     
     
         15 . The method of  claim 10 , wherein, when the controller activates both the heat pump and the fueled heater at the given time to heat the conditioned environment, the fueled heater and the heat pump each operate between 0% and 100% of respective rated outputs. 
     
     
         16 . The method of  claim 10 , further comprising:
 activating an electric heater in place of the fueled heater at the given time when a fuel supply for the fueled heater is below a threshold reserve level or a renewable energy source associated with the electric heater is available at a threshold generation level.   
     
     
         17 . The method of  claim 10 , wherein the indoor heat exchanger and the fueled heater are located in a shared cabinet that is ducted into an airflow path of the conditioned environment. 
     
     
         18 . A computer readable medium including instructions, that when executed by a processor, cause the processor to perform operations including:
 activating, by a controller, a heat pump to heat a conditioned environment;   detecting, using a sensor, an air rise temperature across a heat exchanger of the heat pump located in or in communication with the conditioned environment;   determining, using the controller, whether the air rise temperature is below a triggering threshold; and   when the air rise temperature is below the triggering threshold, activating, by the controller, a fueled heater to heat the conditioned environment at the same time as the heat pump at a given time.   
     
     
         19 . The computer readable medium of  claim 18 , the operations further comprise, in response to detecting that the air rise temperature across the heat exchanger is below the triggering threshold:
 decreasing an output of the heat pump; and   in response to decreasing the output of the heat pump to 0% of rated output:
 operating only the fueled heater to heat the conditioned environment; 
 detecting, using the sensor, the air rise temperature across the heat exchanger at a subsequent time to the given time; 
 determining, using the controller, whether the air rise temperature is above a sufficiency threshold; and 
 when the air rise temperature is above the sufficiency threshold, activating, by the controller, the heat pump to heat the conditioned environment contemporaneously with the fueled heater. 
   
     
     
         20 . The computer readable medium of  claim 18 , wherein, when the controller activates both the heat pump and the fueled heater at the given time to heat the conditioned environment, the fueled heater and the heat pump each operate at less than 100% of respective rated outputs.