Activation and deactivation of a purge unit of a vapor compression system based at least in part on conditions within a condenser of the vapor compression system
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Solution Overview
Problem
Vapor compression systems, such as chillers, face efficiency reduction due to non-condensables like air and atmospheric gases entering the condenser, which require purge units to remove, but these units consume power and reduce overall system efficiency when active.
Innovation Solution
Implementing a control system that selectively activates and deactivates the purge unit based on conditions within the condenser, such as refrigerant-to-air ratios and time since last purge, to minimize active duration and power consumption while maintaining efficiency by strategically managing the purge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the purge unit is continuously activated to remove non-condensables, then the chiller efficiency is maintained, but the power consumption increases
Solution Approach 1:
The purge unit operates periodically rather than continuously, activating only when non-condensable accumulation reaches threshold levels. The controller monitors condenser conditions and triggers purge cycles intermittently, maintaining chiller efficiency while significantly reducing power consumption compared to continuous operation.
Solution Approach 2:
The system incorporates a controller that monitors condenser conditions (such as pressure, temperature, or non-condensable concentration) and uses this feedback to determine when purge unit activation is necessary. This closed-loop control ensures the purge unit operates only when needed to maintain efficiency, avoiding unnecessary energy consumption.
2Use of energy by moving object
If the purge unit is deactivated to save power, then power consumption is reduced, but non-condensables accumulate and decrease chiller efficiency
Solution Approach 1:
The controller continuously monitors condenser conditions and activates the purge unit before non-condensable accumulation significantly impacts chiller efficiency. By taking preliminary action at threshold levels, the system prevents efficiency degradation while minimizing purge unit operation time, thus saving power.
Solution Approach 2:
The system dynamically adjusts purge unit operation based on real-time condenser conditions. Rather than fixed continuous or off states, the purge unit operates with variable timing and duration responsive to actual non-condensable accumulation rates, optimizing the balance between efficiency maintenance and power consumption.
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 reduces power consumption and maintains system efficiency by minimizing the duration of purge unit operation while effectively preventing non-condensable accumulation, thus enhancing the overall performance of vapor compression systems.
Implementation Method 1
The purge unit can include an independent (secondary) vapor compression system that is used to cool and condense refrigerant from a mixture of refrigerant vapor and non-condensables extracted from the chiller
Implementation Method 2
The purge unit can include an independent (secondary) vapor compression system that is used to cool and condense refrigerant from a mixture of refrigerant vapor and non-condensables extracted from the chiller
Data Source
AI summary
Embodiments of the present disclosure are directed toward purge units of vapor compression systems, and methods of control thereof, that selectively activate and deactivate the purge unit in response to one or more conditions to, for example, control refrigerant-to-air ratios while still minimizing the durations of the purge cycles. For example, in certain embodiments, these conditions may include conditions within the chiller condenser, time since last purge activation, time since last venting of non-condensables, and combinations thereof. By reducing an amount of time that the purge unit would be active without removing a substantial amount non-condensables from the vapor compression system, present embodiments reduce the power consumption of the purge unit, as well as the vapor compression system as a whole, while still being responsive to prevent or mitigate a loss of efficiency due to a substantial accumulation of non-condensables in the condenser of the vapor compression system.