Method for controlling a fan device of an evaporator in a heat pump circuit
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Solution Overview
Problem
Heat pump circuits face challenges in maintaining stable operating behavior across varying temperature and humidity conditions, leading to inefficient heat exchange and increased frequency of de-icing operations.
Innovation Solution
A method for controlling the fan device of a heat pump circuit by measuring the temperature difference between the first medium between the evaporator and compressor and the second medium upstream of the evaporator, adjusting the fan's delivery rate based on this difference to maintain a constant temperature difference in specific ranges, thereby stabilizing the operating behavior and reducing ice formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan speed is controlled based on the temperature of the second medium (ambient air), then the heat exchange efficiency is improved, but the operating behavior becomes unstable in certain temperature ranges
Solution Approach 1:
The control method uses feedback from two temperature sensors - one measuring the first medium temperature between evaporator and compressor, and another measuring the second medium temperature upstream of evaporator. The fan speed is adjusted based on the temperature difference between these two measurements, creating a closed-loop control system that stabilizes operating behavior while maintaining heat exchange efficiency.
Solution Approach 2:
The invention changes the control parameter from absolute temperature of the second medium to the temperature difference between the first and second media. This parameter transformation resolves the instability issue in certain temperature ranges while preserving the ability to optimize heat exchange efficiency across varying ambient conditions.
2Productivity
If the fan delivery rate is increased to accelerate heat exchange, then the cooling performance is improved, but evaporator icing increases
Solution Approach 1:
The control system continuously monitors the temperature difference between the first medium (refrigerant) and second medium (ambient air) and adjusts fan speed accordingly. When the temperature difference indicates approaching icing conditions, the system reduces fan delivery rate, preventing ice formation while maintaining optimal cooling performance during normal operation.
3Productivity
If the fan operates at high delivery rate continuously, then the heat exchange efficiency is maximized, but the fan drive becomes vulnerable to damage
Solution Approach 1:
The fan delivery rate is dynamically adjusted based on real-time temperature difference measurements rather than operating at a fixed high speed. This dynamic control allows the system to maximize heat exchange efficiency when conditions permit while reducing fan load and protecting the drive from damage during extreme temperature 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 enhances the operating stability and reliability of the heat pump circuit, particularly in diverse humidity conditions, by optimizing the fan's rotational speed and reducing the frequency of de-icing operations, thus extending the time between de-icing events and protecting the system from damage.
Implementation Method 1
The evaporator is fluidically connected to the compressor via a first medium. A fan is provided at the evaporator, designed to pump a second medium to the evaporator to achieve heat exchange between the first and second media.
Implementation Method 2
achieve heat exchange between the first and second media
Data Source
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AI summary
The invention relates to a method for controlling a fan device of an evaporator of a heat pump circuit, and to a heat pump circuit comprising a compressor, a control device, and an evaporator, wherein the compressor pumps a first medium from the evaporator, wherein a fan device is provided which is configured to convey a second medium to the evaporator, wherein a first temperature sensor is provided, wherein the first temperature sensor measures a first temperature of the first medium between the evaporator and the compressor, wherein a second temperature sensor is provided, wherein the second temperature sensor measures a second temperature of the second medium upstream of the evaporator, and wherein the control device controls a delivery rate of the fan device as a function of a difference between the first temperature and the second temperature.