Refrigerant Flow Sequencer for Reheat Coil Flooding Control
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Solution Overview
Problem
Vapor-compression air conditioning systems face issues with unwanted refrigerant flow during heat exchanger control valve transitions and compressor flooding due to pressure and temperature fluctuations, especially during the heating mode, leading to system undercharging.
Innovation Solution
A refrigerant flow sequencer is introduced between the system reversing valve and the reheat heat exchanger, comprising a flow restrictor and O-ring mechanism that regulates refrigerant flow based on pressure differences, acting as a check valve to prevent unwanted flow and flooding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a refrigerant bypass is added to return refrigerant from inactive components to the active flow path, then refrigerant distribution is improved, but compressor flooding occurs due to slow transition time of control valve actuator
Solution Approach 1:
A flow restrictor is introduced as an intermediary component in the refrigerant bypass line. This flow restrictor limits the rate at which refrigerant can flow through the bypass, preventing excessive refrigerant from reaching the compressor during rapid valve transitions. The flow restrictor acts as a mediator between the bypass valve and compressor, controlling the refrigerant flow rate to safe levels while still allowing proper refrigerant distribution.
2Speed
If heat exchanger control valve transitions rapidly, then system response time is improved, but pressure fluctuations cause unwanted refrigerant flow and compressor flooding
Solution Approach 1:
The flow restrictor is pre-installed in the bypass line to cushion against potential harmful effects of rapid valve transitions. By limiting the maximum flow rate beforehand, the system is protected from pressure fluctuations and refrigerant surges that would otherwise cause compressor flooding during rapid control valve transitions.
3Productivity
If refrigerant flow is unrestricted in bypass line, then refrigerant return efficiency is improved, but system undercharging occurs during heating mode due to refrigerant migration
Solution Approach 1:
The flow restrictor changes the flow parameters in the bypass line by limiting the maximum flow rate and creating a pressure differential. This parameter change ensures that during heating mode, refrigerant migration to the charge reservoir and reheat coil is controlled, preventing system undercharging while still maintaining efficient refrigerant return during cooling mode.
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 refrigerant flow sequencer effectively manages pressure differences to prevent compressor flooding and ensures proper refrigerant distribution, maintaining system balance and preventing undercharging during heating mode operations.
Implementation Method 1
A refrigerant flow sequencer is introduced between the system reversing valve and the reheat heat exchanger, comprising a flow restrictor and O-ring mechanism that regulates refrigerant flow based on pressure differences
Implementation Method 2
comprising a flow restrictor and O-ring mechanism that regulates refrigerant flow based on pressure differences, acting as a check valve to prevent unwanted flow and flooding
Data Source
AI summary
A vapor-compression air conditioning system comprising a blower positioned in a return air flow path from a conditioned space, a reheat heat exchanger positioned in the return air flow path and downstream from the blower, a system reversing valve fluidly coupled to the reheat heat exchanger, and a refrigerant flow sequencer interposed the system reversing valve and the reheat heat exchanger. A method of manufacturing an air conditioning system is also provided.