Multi-Evaporator Refrigerant Distribution Using Common Superheat Sensing
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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 do not ensure maximum utilization of each evaporator's potential.
Innovation Solution
A method that modifies refrigerant distribution by adjusting the mass flow through a selected evaporator while monitoring superheat (SH) to maintain optimal performance, using a single temperature sensor at the common outlet to control the distribution among all evaporators, ensuring a mixed gaseous/liquid phase is present along each evaporator without allowing liquid refrigerant to pass through, thereby optimizing refrigeration capacity and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate temperature sensors are installed for each evaporator to control refrigerant distribution, then the refrigeration capacity of each evaporator can be monitored, but the system complexity and component count increase
Solution Approach 1:
The patent merges the temperature measurement function into a single common outlet sensor that monitors the mixed refrigerant from all evaporators. Instead of installing separate sensors in each evaporator, one sensor at the common outlet captures the combined thermal state, reducing component count while still enabling control of refrigerant distribution based on the mixed temperature signal.
Solution Approach 2:
The common outlet temperature sensor serves a universal function for all evaporators simultaneously. A single sensor location provides measurement data that is used to control refrigerant distribution to multiple evaporators, making the sensing system multi-functional rather than requiring dedicated sensors for each evaporator unit.
2Productivity
If refrigerant distribution is controlled based on individual evaporator temperatures, then each evaporator can operate at optimal capacity, but the system requires more components and higher power consumption
Solution Approach 1:
The patent combines the control function for multiple evaporators into a single control strategy based on the mixed refrigerant temperature at the common outlet. By merging the control decisions and using a single sensor location, the system achieves coordinated optimization of all evaporators without the energy overhead of multiple independent control loops and sensors.
3Ease of operation
If multiple temperature sensors are used to monitor each evaporator, then precise control of refrigerant distribution is achieved, but the system cost and component count increase
Solution Approach 1:
The patent merges multiple sensing functions into a single sensor location at the common outlet. This single sensor provides the necessary temperature information to control refrigerant distribution to all evaporators, eliminating the need for multiple separate sensors and reducing both component count and system cost.
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 without compromising system performance, while also providing a cost-effective solution by using shared sensors and adaptive adjustments to maintain optimal refrigerant distribution.
Implementation Method 1
the refrigerant is alternatingly compressed and expanded, thereby providing either refrigeration or heating
Implementation Method 2
each evaporator receives a correct amount of refrigerant... ensuring that a mixed gaseous/liquid phase is present along the entire length of each evaporator
Implementation Method 3
a flow of refrigerant circulates and is alternatingly compressed and expanded
Implementation Method 4
each evaporator receives a correct amount of refrigerant to obtain a proper hysteresis control of the corresponding refrigeration compartment
Data Source
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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.