Heat Medium Pump Control for Air-Conditioner Corrosion Prevention
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Solution Overview
Problem
In air-conditioning systems, when the heat medium circulation is stagnant or not circulated for a period, an oxide film is not formed at the connection points of heat medium devices and pipes, leading to corrosion due to reduced oxygen supply, which existing technologies fail to prevent effectively.
Innovation Solution
An air-conditioning apparatus with a heat medium circulation circuit, a pump, a detection unit, and a controller that monitors and controls the pump operation to ensure the heat medium flows adequately, promoting oxide film formation at connection points by comparing operation times with set thresholds and adjusting pump operation accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the heat medium is not circulated for a certain period of time, then the operation time is reduced and energy is saved, but the oxide film is not formed and corrosion progresses at the connection portion
Solution Approach 1:
The system performs preliminary oxidation by circulating the heat medium with air introduced before normal operation begins, creating an oxide film in advance on the connection portions. This preliminary action ensures corrosion protection is established before the system enters idle periods where prolonged stagnation would otherwise occur.
Solution Approach 2:
The control unit periodically introduces air into the heat medium and operates the pump for a predetermined time to form oxide films at regular intervals. This periodic action maintains protective oxide layers even when the system experiences extended periods without heat medium circulation, balancing energy savings with corrosion prevention.
2Reliability
If the heat medium circulates continuously, then the oxide film is formed and corrosion is prevented, but energy consumption increases
Solution Approach 1:
Instead of continuous pump operation, the system uses periodic pumping combined with periodic air introduction to maintain oxide films. The pump operates only for predetermined time intervals at scheduled periods, significantly reducing energy consumption while maintaining corrosion protection through the periodically renewed oxide layers.
Solution Approach 2:
The system introduces air (containing oxygen) into the heat medium to accelerate oxide film formation on connection portions. This accelerated oxidation process creates protective films quickly during brief pump operation periods, eliminating the need for continuous circulation while ensuring reliable corrosion protection.
3Adaptability or versatility
If different metal materials are used for heat medium device and heat medium pipe, then connection flexibility is improved, but galvanic corrosion occurs at the connection portion
Solution Approach 1:
The system converts the harmful effect of metal contact (galvanic corrosion risk) into a beneficial process by intentionally introducing oxygen to form oxide films on the connection portions. These oxide films act as protective barriers that prevent the galvanic corrosion that would otherwise occur between dissimilar metals, transforming the potential harm into a protective mechanism.
Solution Approach 2:
By introducing air into the heat medium and accelerating oxidation at connection portions, the system creates dense oxide films on dissimilar metal surfaces. These oxide films serve as protective layers that prevent galvanic corrosion, enabling the use of different metal materials for the heat medium device and pipes while maintaining connection reliability.
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
The apparatus effectively prevents corrosion at connection points by ensuring the formation of an oxide film, even when the heat medium is not circulated for extended periods, by forcibly circulating the heat medium and adjusting pump operation based on detected flow states.
Implementation Method 1
a pump provided on the heat medium circulation circuit and configured to circulate the heat medium
Implementation Method 2
an oxide film is formed on the connection portion of the heat medium device and the heat medium pipe owing to an oxygen component in the heat medium
Data Source
AI summary
An air-conditioning apparatus includes: a heat medium circulation circuit including: a heat medium device, a heat medium pipe, a pump, a heat medium detection unit, and a controller that includes a count unit to count an air-conditioning operation time and count a pump operation time based on heat medium detection information of the heat medium detection unit, a storage unit storing a set air-conditioning time and a set pump time, a comparison unit to compare the air-conditioning operation time with the set air-conditioning time and compare the pump operation time with the set pump time, and a device control unit to control driving of the pump so that the pump operation time reaches or exceeds the set pump time when the air-conditioning operation time is longer than or equal to the set air-conditioning time and the pump operation time is shorter than the set pump time.