Motorized Valve System for Sequential Refrigerant Pump-Down Control
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Solution Overview
Problem
HVAC systems face challenges in safely managing refrigerants with lower Global Warming Potential (GWP) that are mildly flammable, as they pose a risk when residual quantities accumulate inside structures, requiring effective methods to isolate and remove these refrigerants to mitigate flammability hazards.
Innovation Solution
A valve system comprising a motor, a first valve, a second valve, and a controller, where the motor's shaft actuates both valves to create specific positions controlling the flow of refrigerant through suction and liquid lines, allowing for sequential and controlled pumping down of refrigerant from interior spaces to exterior condensing units, reducing the risk of flammability hazards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If flammable refrigerants with lower GWP are used to reduce environmental impact, then global warming potential is reduced, but flammability hazard increases when refrigerant accumulates in interior spaces
Solution Approach 1:
The system extracts removes refrigerant from the interior space between cooling cycles by closing the liquid line valve and opening the suction line valve, allowing the compressor to pump refrigerant out through the suction line. This extraction eliminates the flammability hazard by removing the refrigerant from the interior space where it could accumulate to dangerous levels.
2Ease of repair
If manually operated service valves are used to isolate the condensing unit, then system serviceability is improved, but automated refrigerant removal capability is reduced
Solution Approach 1:
The system merges the functions of manual service valves with automated pump-down capability by integrating motorized actuators with the existing valve bodies. The actuators are controlled by a controller that automatically sequences the liquid line and suction line valves to perform refrigerant removal, combining ease of service access with automated safety functionality.
Solution Approach 2:
The system enables self-service automated refrigerant removal by using a controller to monitor system conditions and automatically actuate the valves and compressor to pump down refrigerant between cycles without requiring manual intervention. This maintains serviceability while adding automated safety.
3Productivity
If refrigerant is left in interior portions of the HVAC system between cycles, then system readiness is improved, but safety risk increases due to potential flammability
Solution Approach 1:
The system performs preliminary action by automatically removing refrigerant from the interior space at the end of each cooling cycle before the system shuts down. The controller sequences the valve actuation and compressor operation to pump down refrigerant proactively, ensuring the interior space is clear of flammable refrigerant before the next cycle begins, thus maintaining both safety and readiness.
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 enables safe and efficient removal of refrigerant from interior spaces, reducing the risk of flammability hazards and allowing for the use of lower GWP refrigerants, thereby addressing environmental concerns and improving system safety.
Implementation Method 1
The motor has a shaft. The first valve is connected to the shaft and is rotatable to an open position, through which fluid flows to a first channel, and a close position, in which fluid is prevented from flowing through the first channel.
Implementation Method 2
The liquid refrigerant boils while absorbing heat to be removed from the conditioned space, thereby cooling blowing air before the refrigerant is returned to a compressor in the outdoor condensing unit using a suction line.
Implementation Method 3
The liquid refrigerant boils while absorbing heat to be removed from the conditioned space
Implementation Method 4
The liquid refrigerant boils while absorbing heat
Data Source
AI summary
A valve system includes a motor, a first valve, a second valve, and a controller. The first valve is connected to the motor shaft and is rotatable to an open position, in which fluid flows through a first channel, and a close position, in which fluid is prevented from flowing through the first channel. The second valve is connected to the motor shaft and is rotatable to an open position, in which fluid flows through a second channel from a first end to a second end, and to a close position, in which fluid is prevented from flowing through the second channel. The controller is connected to the motor and can sequentially actuate the first valve and the second valve to create at least a first, second, third, and fourth position.