Energy control system

Abstract

A method for adjusting an economic balance point in a dual fuel HVAC system includes a furnace, a heat pump and a control system. The method comprises providing a control device having a preprogrammed algorithm for controlling the HVAC system, providing a communication path between the control device and at least one component of the HVAC system, and accessing current fuel cost data; determining an economic balance point temperature based on the current fuel cost data; and updating the economic balance point temperature in the preprogrammed algorithm to adjust an actual balance point of the HVAC system.

1 . A method for adjusting a balance point temperature in a dual fuel HVAC system having a furnace, a heat pump and a control system, by monitoring operating costs for the furnace and the heat pump, the method comprising:
 accessing fuel cost data;   determining a balance point temperature based on the fuel cost data; and   updating the balance point temperature in a preprogrammed algorithm to adjust a balance setpoint of the HVAC system, the balance setpoint being the exterior temperature below which the HVAC system switches from the heat pump to the furnace as a heat source.   
     
     
         2 . The method of  claim 1 , also comprising:
 sensing an exterior temperature; and   controlling an interior temperature by operating the furnace when the exterior temperature is less than the balance setpoint, and by operating the heat pump when the exterior temperature is greater than or equal to the balance setpoint.   
     
     
         3 . The method of  claim 1 , also including the steps of:
 determining at least one predetermined parameter of the heat pump at a plurality of exterior temperatures.   
     
     
         4 . The method of  claim 3 , further comprising:
 continually determining the at least one predetermined parameter and incorporating the at least one predetermined parameter into an algorithm to calculate an application balance point temperature, below which the heat pump heating capacity is less than the rate of heat loss of structure, in response to a change in the at least one predetermined parameter.   
     
     
         5 . The method of  claim 4 , wherein the at least one predetermined parameter includes heating capacity, energy consumption, or efficiency. 
     
     
         6 . The method of  claim 1 , wherein the control system comprises a microprocessor-based electronic controller configured to implement the algorithm, receive input values and generate output signals. 
     
     
         7 . The method of  claim 1 , wherein the HVAC system comprises a plurality of system components, the system components comprising a heat pump controller, a furnace controller, a room thermostat, an independent control panel, and a personal computer; the system components in data communication with one another through a network. 
     
     
         8 . The method of  claim 7 , wherein the algorithm may be preprogrammed into at least one of the system components. 
     
     
         9 . The method of  claim 1 , wherein system components are connected through thermostat wires, and one of the system components receives the data to process the algorithm. 
     
     
         10 . The method of  claim 1 , wherein the control system is connected to a network having an Internet connection. 
     
     
         11 . The method of  claim 1 , wherein the HVAC system is in electronic communication with a network that may be connected through a network coupling device. 
     
     
         12 . An HVAC system comprising:
 a furnace, a heat pump, a controller, and a communication path between the controller and at least one component of the HVAC system;   wherein the controller is configured to access a remote database including a current fuel cost data and retrieve the current fuel cost data, determine a balance point temperature based on the current fuel cost data, and update a balance point temperature in a preprogrammed algorithm to adjust a balance setpoint of the HVAC system.   
     
     
         13 . The HVAC system of  claim 12 , wherein the controller is configured to determine at least one predetermined parameter of the heat pump at a plurality of exterior temperatures. 
     
     
         14 . The HVAC system of  claim 13 , wherein the preprogrammed algorithm is configured to periodically determine at predetermined intervals the at least one predetermined parameter and calculate an application balance point exterior temperature, below which exterior temperature the heat pump heating capacity is less than the rate of heat loss of structure, in response to a change in the at least one predetermined parameter. 
     
     
         15 . A method for controlling energy use in a structure, the structure including a dual fuel HVAC system having a furnace, a heat pump and a control system, comprising:
 selecting an indoor temperature setpoint, a heat loss for the structure, and a heating capacity of the system   determining an application balance point exterior temperature below which the heat pump heating capacity is less than the rate of heat loss of the structure, based on one or more of the selected indoor temperature, the heat loss for the structure, and the heating capacity of the system;   determining an operating cost of the furnace;   determining an operating cost for the heat pump;   determining a balance point temperature based on a point of intersection of the heat pump operating costs and the furnace operating cost;   comparing the application balance point temperature to a balance point temperature and generating a balance setpoint, the balance setpoint being selected as the greater value of the application balance point temperature and the balance point temperature; and   monitoring system parameters periodically to determine whether a change in the balance setpoint has occurred as a result of changes in system parameters.   
     
     
         16 . The method of  claim 15 , wherein the step of determining the operating cost for the heat pump comprises:
 determining the electric power consumption of the heat pump,   determining the cost of electricity,   calculating heat pump energy cost for the heat pump;   
     
     
         17 . The method of  claim 15 , further comprising:
 controlling the system to operate the heat pump based on the exterior temperature equaling or exceeding the balance setpoint, and to operate the furnace based on the exterior temperature being less than the balance setpoint.   
     
     
         18 . The method of  claim 15 , further comprising:
 determining that a current balance setpoint value differs from a preceding balance setpoint and replacing the balance setpoint with the current balance setpoint.   
     
     
         19 . The method of  claim 15 , further comprising:
 determining the heat loss based on a design heat loss of a structure at a predetermined outdoor temperature   
     
     
         20 . The method of  claim 15 , wherein the heating capacity of the heat pump is determined by plotting a curve of the heating capacity of the heat pump for a range of exterior temperatures. 
     
     
         21 . The method of  claim 20 , wherein the balance point temperature is determined by an intersection of a heat pump electrical consumption cost curve and a furnace heating cost curve. 
     
     
         22 . The method of  claim 21 , wherein the application balance point is defined as an intersection of a heat loss curve of the structure and a heating capacity curve of the heat pump.