Heat Pump Flow Temperature Control During Defrosting
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Solution Overview
Problem
Existing heating systems using air-source heat pumps face inefficiencies and discomfort due to fixed flow temperatures, especially in intermediate seasons, and inaccurate temperature settings during defrosting modes, leading to increased energy consumption and unstable room temperatures.
Innovation Solution
Implement a control system that adapts the flow temperature of the heating medium in real-time based on outdoor conditions, ignoring temperature sensor readings during defrosting to prevent false settings, and uses an inverter-controlled compressor to optimize energy use, while defrosting modes employ alternative methods to minimize sensor interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a fixed high flow temperature is set in existing heating systems, then sufficient heat can be provided to heat emitters in all operating conditions, but the floor temperature becomes excessively high causing discomfort and energy efficiency decreases
Solution Approach 1:
The patent implements dynamic flow temperature control that continuously adapts the flow temperature based on outdoor temperature conditions. The control unit adjusts the flow temperature to be just sufficient for the current heating demand, replacing the fixed high temperature setting with a dynamic adjustment mechanism that responds to changing ambient conditions.
Solution Approach 2:
The patent changes the flow temperature parameter dynamically based on outdoor temperature. By establishing a relationship between outdoor temperature and optimal flow temperature, the system adjusts this critical parameter to match actual heating needs, preventing both overheating and insufficient heating conditions.
2Ease of operation
If the compressor is controlled with on/off switching at fixed frequency, then the system is simple to operate, but energy consumption increases and efficiency decreases particularly in intermediate seasons
Solution Approach 1:
The patent replaces fixed-frequency on/off compressor control with variable-frequency continuous control. The control unit adjusts the compressor frequency dynamically based on heating demand and outdoor conditions, allowing the compressor to operate at optimal speeds rather than switching between fixed states, thereby reducing energy consumption.
Solution Approach 2:
The patent implements continuous compressor operation with variable frequency rather than intermittent on/off cycling. This continuous adjustment allows the system to maintain optimal heating performance while consuming less energy, as the compressor operates smoothly at the exact frequency needed for current conditions rather than cycling at fixed high frequency.
3Ease of manufacture
If the outdoor temperature sensor is placed in the outdoor unit, then the temperature measurement is convenient, but the sensor is influenced by radiated heat from the evaporator/condenser surface causing measurement errors
Solution Approach 1:
The patent introduces a shielding structure as an intermediary between the outdoor temperature sensor and the evaporator/condenser surface. This shield blocks radiated heat from reaching the sensor, allowing the sensor to remain conveniently located in the outdoor unit while preventing measurement errors caused by thermal radiation interference.
4Reliability
If defrosting mode is performed by reversing refrigerant flow or using electric heaters, then the evaporator ice cover is removed, but the temperature sensor reading becomes inaccurate due to radiated heat affecting the sensor
Solution Approach 1:
The patent uses the shielding structure as an intermediary during defrosting operations to block radiated heat from reaching the temperature sensor. This allows the system to perform reliable defrosting while preventing the sensor from recording erroneous temperature readings that would result from thermal radiation during the defrosting process.
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 enhances comfort and efficiency by maintaining optimal flow temperatures, reducing energy consumption, and ensuring reliable heating by adapting to ambient conditions and preventing inaccurate temperature settings during defrosting.
Implementation Method 1
the temperature sensor will be influenced by the surface temperature of the evaporator/condenser of the heat pump, i.e. by the radiated heat if any
Implementation Method 2
transfer of heat between the outdoor air and the refrigerant
Implementation Method 3
transfer of heat between the outdoor air and the refrigerant
Implementation Method 4
a heating medium piping for circulating a heating medium and flowing the heating medium through the condenser exchanging heat between the refrigerant and the heating medium
Implementation Method 5
a compressor... driven at the same frequency independent of the heat demand
Implementation Method 6
an expansion means connected by a refrigerant piping in a cycle
Implementation Method 7
transfer heat from the heating medium to the refrigerant and, hence, to the evaporator
Implementation Method 8
heat being applied to the evaporator for melting the ice cover on the outer surface of the evaporator
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A heating comprising: a heat pump having an evaporator (14), a compressor (15), a condenser (25) and an expansion means (13) connected by a refrigerant piping (11, 12, 16, 27) in a cycle, at least the evaporator being arranged in an outdoor unit (10); a heating medium piping (21, 31, 34, 35, 35, 22) formed to circulate a heating medium and to flow the heating medium through the condenser exchanging heat between the refrigerant and the heating medium; an outdoor temperature sensor (19) arranged in or at the outdoor unit; and a control configured to set the flow temperature of the heating medium based on the outdoor temperature measured by the sensor and to perform a defrosting mode (B) defrosting the outdoor evaporator, wherein the control is configured to ignore the measurement result of the outdoor temperature sensor during the defrosting mode. Further, the present invention also relates to a corresponding control method.