Heat Medium Pump Voltage Control to Prevent Pipe Erosion
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Solution Overview
Problem
Air-conditioning apparatuses using heat medium circulation circuits face erosion corrosion issues due to high flow velocities of the heat medium, which can lead to pipe damage and corrosion, especially when the pump operates at maximum capacity.
Innovation Solution
Incorporating a voltage drop device, such as an AC reactor, to reduce the voltage applied to the pump based on the current supplied, thereby controlling the flow rate and velocity of the heat medium, preventing erosion corrosion in the pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump is driven at maximum capacity to ensure sufficient heat medium circulation, then the heat medium flow rate is increased, but the flow velocity increases causing erosion corrosion in the flow passage
Solution Approach 1:
The patent changes the electrical parameter (voltage) applied to the pump to control its operating point. By reducing the voltage from the rated value, the pump operates at a lower flow rate and flow velocity, preventing erosion corrosion while still providing sufficient heat medium circulation for the air-conditioning load.
Solution Approach 2:
The patent uses electrical current as a proxy indicator for pump output and heat medium flow rate. Instead of directly measuring flow velocity or using complex flow measurement devices, the system monitors the electrical current consumed by the pump, which correlates with the heat medium circulation capacity, and adjusts voltage accordingly.
2Adaptability or versatility
If a pump with larger capacity than required is selected to account for future expansion and pressure loss, then the system has sufficient capacity for additional indoor units, but the flow velocity becomes excessively high causing pipe damage
Solution Approach 1:
The patent makes the pump operation dynamic by adjusting the applied voltage based on the actual number of operating indoor units and current load requirements. The pump operates at different capacity levels rather than always at maximum, allowing the system to adapt to varying numbers of connected indoor units while maintaining safe flow velocities.
Solution Approach 2:
The patent implements a feedback control mechanism where the electrical current consumed by the pump is monitored, and this information is used to adjust the voltage applied to the pump. The control device reduces voltage when current exceeds a predetermined threshold, creating a closed-loop control system that prevents erosion corrosion while maintaining adequate circulation capacity.
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 solution effectively reduces the flow velocity of the heat medium, preventing erosion corrosion and allowing for efficient operation without the need for additional flow measurement devices, thereby reducing costs and ensuring system reliability.
Implementation Method 1
the voltage drop device reduces a voltage that is applied to the pump based on a value of a current that is supplied to the pump
Implementation Method 2
The pump sends a heat medium that contains water or brine and transfers heat
Implementation Method 3
The heat-source-side device heats or cools the heat medium before the heat medium is sent to the indoor heat exchanger
Implementation Method 4
The indoor heat exchanger causes heat exchange to be performed between the heat medium and an indoor air in an air-conditioned space
Data Source
AI summary
An air-conditioning apparatus according to the present disclosure includes a heat medium circulation circuit, a heat-source-side device, and a voltage drop device. In the heat medium circulation circuit, a pump, an indoor heat exchanger, and a flow control device are connected by pipes to circulate the heat medium. The pump sends a heat medium that contains water or brine and transfers heat. The indoor heat exchanger causes heat exchange to be performed between the heat medium and an indoor air in an air-conditioned space. The flow control device controls a flow rate of the heat medium in the indoor heat exchanger. The heat-source-side device heats or cools the heat medium before the heat medium is sent to the indoor heat exchanger. The voltage drop device reduces a voltage that is applied to the pump based on a value of a current that is supplied to the pump, in association with a flow rate of the heat medium in the heat medium circulation circuit.