Heat Pump Ambient Sensing for Frost Prevention Control
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Solution Overview
Problem
Existing heat pumps face challenges in operating effectively at low temperatures due to icing issues, which require costly backup heat sources and complex control systems, and existing solutions like pressure switches have inaccuracies and high variability, leading to inefficient frost detection and prevention.
Innovation Solution
A monitoring and control system for heat pumps that uses a temperature sensor and a control program to determine ambient temperature by measuring the temperature at or near the controller, allowing for accurate detection of frost conditions without external sensors or complex electronics, thereby preventing icing and optimizing low-temperature operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is placed on the evaporator tube to directly measure tube surface temperature for frost detection, then measurement precision is improved, but device complexity and reliability deteriorate due to required wiring, electronic circuitry, and sensor vulnerability to damage from weather, rodents, insects, or human tampering
Solution Approach 1:
The patent uses the controller's internal temperature sensor as an intermediary to indirectly measure the evaporator tube surface temperature. Instead of placing a sensor directly on the tube, the system measures the temperature at the controller location and uses this as a proxy, eliminating the need for additional wiring and external sensors while maintaining frost detection capability
Solution Approach 2:
The controller's existing temperature sensor and processing capabilities are utilized to perform frost detection functions. The system serves itself by using its own internal resources (controller's temperature sensor) rather than requiring separate dedicated components, thereby reducing overall system complexity
2Device complexity
If a pressure switch is used to indirectly monitor refrigeration system pressure to determine evaporating temperature, then device complexity is reduced, but measurement precision deteriorates due to inaccuracy and high variability in frost detection
Solution Approach 1:
The patent introduces the controller's internal temperature sensor as an intermediary measurement point. Instead of using pressure switch readings that have high variability, the system uses the temperature sensor's direct temperature measurement as a more reliable indicator of frost conditions, maintaining simplicity while improving accuracy
Solution Approach 2:
The patent replaces the mechanical pressure switch system with an electronic temperature sensing approach. By substituting the pressure-based indirect measurement with temperature-based direct measurement using the controller's sensor, the system achieves better precision while maintaining acceptable complexity levels
3Reliability
If the heat pump is shut off at the freeze point to prevent icing, then reliability is improved, but productivity deteriorates due to loss of low temperature operation capability
Solution Approach 1:
The system performs preliminary frost detection using the controller's temperature sensor before icing actually occurs. By detecting temperature trends and conditions that precede frost formation, the system can take preventive actions (such as adjusting operation parameters) rather than simply shutting off, thereby maintaining productivity while preventing frost
Solution Approach 2:
The system continuously monitors temperature at the controller location and uses this feedback to dynamically adjust heat pump operation. Rather than a simple on/off control at freeze point, the feedback mechanism allows the system to optimize operation in low temperature conditions while preventing frost, thereby maintaining both reliability and productivity
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 solution provides a cost-effective and reliable method to determine ambient temperature and prevent icing, maximizing heat pump efficiency and extending operational range without the need for additional sensors or complex electronics, thus reducing costs and improving reliability.
Implementation Method 1
A monitoring and control system for heat pumps uses a temperature sensor and a control program to determine ambient temperature by measuring the temperature at or near the controller
Implementation Method 2
Air source heat pumps have been used in various applications to remove heat from the outdoor air and move it to another fluid or heat sink
Implementation Method 3
the moisture it contained is left behind frozen on the evaporator tube
Implementation Method 4
a compressor configured to draw the gas refrigerant from the evaporator arrangement and compress the gas refrigerant
Implementation Method 5
a water heater arranged downstream of the evaporator arrangement and configured to be heated by the gas refrigerant
Implementation Method 6
the moisture it contained is left behind frozen on the evaporator tube. In this manner, subsequent and severe icing can occur
Data Source
AI summary
Disclosed is a monitoring and control system for an air source heat pump apparatus having a controller to control at least one operation of the heat pump apparatus, a temperature sensor to detect the temperature in a specified area at, near, and/or around the controller, and an operable component, the system including a control program to: determine the temperature based on the detected temperature of the temperature sensor; determine whether a first condition exists, the first condition including a determination that the controller is powered, but the operable component is not operating; determine whether a second condition exists, the second condition including a determination that the controller is powered, and the operable component is operating; and based at least partially on determinations (a)-(c), determine the ambient temperature at or around the heat pump apparatus.