Multi-Evaporator Refrigerant Distribution Using Common Superheat Feedback
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Solution Overview
Problem
Existing vapor compression systems with multiple evaporators in parallel face challenges in optimizing refrigerant distribution, leading to inefficient use of refrigeration capacity and increased power consumption, particularly when evaporators are arranged in the same refrigerated volume, as they require multiple temperature sensors and cannot ensure maximum utilization of each evaporator's potential.
Innovation Solution
A method that monitors superheat at the common outlet, adjusts refrigerant distribution by altering the mass flow through one evaporator while maintaining a constant total mass flow, detects control parameters based on these changes, and repeats this process for all evaporators to optimize refrigerant distribution and ensure identical degrees of filling, thereby maximizing refrigeration capacity without increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate temperature sensor is installed for each evaporator to control refrigerant distribution, then the refrigeration capacity of each evaporator can be monitored, but the number of components increases and the system complexity increases
Solution Approach 1:
The patent merges the temperature measurement function from multiple separate sensors into a single temperature sensor that measures the temperature of the common refrigerant line. This single sensor provides the necessary information to control refrigerant distribution to multiple evaporators, thereby reducing component count while maintaining measurement capability.
Solution Approach 2:
The single temperature sensor in the common line serves a universal function by providing temperature data that is used to control refrigerant distribution to all evaporators. This multi-functional approach eliminates the need for dedicated sensors for each evaporator while still enabling precise control of refrigerant flow to each unit.
2Productivity
If refrigerant distribution is controlled based on individual evaporator temperatures, then each evaporator receives appropriate refrigerant amounts, but the system cannot ensure maximum utilization of each evaporator's potential refrigeration capacity
Solution Approach 1:
The patent implements a feedback control mechanism where the single temperature sensor continuously monitors the common refrigerant line temperature, and this information is fed back to the control system to dynamically adjust refrigerant distribution. This feedback loop ensures that each evaporator receives the optimal amount of refrigerant to maximize its refrigeration capacity while maintaining energy efficiency.
Solution Approach 2:
The refrigerant distribution system is made dynamic by continuously adjusting the flow to each evaporator based on real-time temperature measurements from the common line. This dynamic control allows the system to adapt to changing conditions and optimize the utilization of each evaporator's refrigeration capacity, preventing energy waste from over- or under-cooling.
3Reliability
If multiple temperature sensors are used for each evaporator in parallel configuration, then individual evaporator performance can be monitored, but the manufacturing cost increases
Solution Approach 1:
The patent combines the temperature monitoring function for multiple evaporators into a single temperature sensor located in the common refrigerant line. This merging approach maintains the ability to monitor evaporator performance while significantly reducing the number of components that need to be manufactured, assembled, and installed, thereby lowering manufacturing costs.
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 method allows for efficient utilization of each evaporator's refrigeration capacity, reduces the number of necessary components, and minimizes power consumption by ensuring optimal operation and performance across all evaporators, while also reducing initial manufacturing costs.
Implementation Method 1
monitoring a superheat, SH, of refrigerant at the common outlet
Implementation Method 2
at least two evaporators fluidly connected in parallel between a compressor and a common outlet
Data Source
AI summary
A method for controlling a refrigerant distribution in a vapour compression system, such as a refrigeration system, e.g. an air condition system, comprising at least two evaporators. The refrigerant distribution determines the distribution of the available amount of refrigerant among the evaporators. While monitoring a superheat, SH, at a common outlet for the evaporators, the distribution of refrigerant is modified in such a manner that a mass flow of refrigerant to a first evaporator is altered in a controlled manner. The impact on the monitored SH is then observed, and this is used for deriving information relating to the behaviour of the first evaporator, in the form of a control parameter. This is repeated for each evaporator, and the refrigerant distribution is adjusted on the basis of the control parameters. The impact may be in the form of a significant change in SH. Alternatively, the control parameter may reflect a change in SH occurring as a result of the modification of the distribution of refrigerant.