Method for controlling an air conditioning system using an economic balance point and a capacity balance point
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Solution Overview
Problem
Heat pump-based HVAC systems in very cold environments often continue to use heat pumps inefficiently even when it is more economical to switch to auxiliary heaters due to an inaccurate economic balance point, leading to increased operating costs and reduced heating capacity.
Innovation Solution
A computer-implemented method that dynamically adjusts a capacity balance point based on real-time temperature measurements and effectiveness of the heat pump in heating the zone, switching to the auxiliary heater when the heat pump is not effective, and periodically correcting the balance point to ensure accurate switching between heat pump and auxiliary heater operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the heat pump continues to operate based on a fixed economic balance point, then the system maintains simplicity in control logic, but the operating cost increases and heating effectiveness decreases when outdoor temperatures drop below the actual switching threshold
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a fixed economic balance point to a dynamic capacity balance point that adapts to real-time conditions. The controller continuously monitors heat pump performance metrics (temperature rise, runtime, cycling patterns) and adjusts the capacity balance point accordingly, allowing the system to optimize the switching threshold between heat pump and auxiliary heater operation based on actual effectiveness rather than relying on static pre-calculated values.
Solution Approach 2:
The patent implements feedback by using the heat pump's actual performance data to inform future control decisions. The controller measures whether the heat pump is achieving desired temperature increases within acceptable timeframes and uses this feedback to adjust the capacity balance point. This closed-loop feedback mechanism ensures that when the heat pump becomes ineffective (e.g., unable to heat sufficiently during very cold periods), the system automatically triggers auxiliary heater operation, thereby reducing energy loss and operating costs.
2Productivity
If the heat pump operates in very cold temperatures beyond its effective capacity, then the system avoids premature switching to auxiliary heater, but the heating capacity becomes insufficient and operating efficiency decreases
Solution Approach 1:
The system dynamically adjusts the capacity balance point based on real-time heat pump performance rather than using a fixed threshold. By continuously monitoring whether the heat pump achieves adequate temperature increases within reasonable timeframes, the system adapts the switching point to current environmental conditions, ensuring that auxiliary heater activation occurs precisely when the heat pump can no longer meet heating demands effectively.
Solution Approach 2:
The patent replaces the traditional mechanical/economic-based switching mechanism (fixed economic balance point based on pre-calculated cost comparisons) with an intelligence-based control system that uses real-time performance monitoring and adaptive algorithms. This intelligent substitution allows the system to assess actual heating effectiveness and make informed decisions about when to switch to auxiliary heating, thereby maintaining reliable heating capacity across varying outdoor temperature conditions.
3Measurement precision
If the system uses a fixed economic balance point determined at installation, then the control logic remains simple and consistent, but the switching accuracy deteriorates when actual heat load conditions differ from assumptions used in the calculation
Solution Approach 1:
The patent transforms the static economic balance point into a dynamic capacity balance point that evolves with system operation. Instead of relying on pre-calculated values based on installation-time assumptions, the controller continuously learns from actual heat pump performance data (temperature rises, runtime requirements, cycling patterns) and adjusts the capacity balance point to reflect current system effectiveness and environmental conditions, thereby maintaining high switching accuracy without complex manual reconfiguration.
Solution Approach 2:
The system performs self-adjustment by automatically monitoring its own performance and modifying the capacity balance point without external intervention. The controller assesses whether the heat pump is meeting heating demands effectively and autonomously determines when to trigger auxiliary heater operation, eliminating the need for manual recalibration or complex user input while maintaining high switching precision across varying operating conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for a more accurate and efficient switching between heat pump and auxiliary heater operation, reducing operating costs and ensuring adequate heating by using the most efficient heating source based on current conditions.
Implementation Method 1
during a heating operation the heat pump will transfer heat from the ambient outside air to the target zone, thereby heating the target zone
Implementation Method 2
An auxiliary heater could be a gas furnace, an electric heater, or the like
Data Source
AI summary
A computer-implemented method is provided of controlling a heating, ventilation, and air-conditioning (HVAC) system having a heat pump and an auxiliary heater to heat an inside zone, the method comprising: setting values for an economic balance point and a temperature set point; setting a capacity balance point to be equal to the economic balance point; measuring an initial inside temperature in the inside zone and an outside temperature outside of a structure containing the inside zone; determining that the initial inside temperature is lower than the temperature set point; determining that the outside temperature is greater than the capacity balance point; activating the heat pump to heat the inside zone; waiting a heating interval while the heat pump is active; determining that the heat pump is not effective in heating the inside zone; and setting the capacity balance point to be equal to the outside temperature.