Parallel Evaporator Cooling System with Superheat-Based Flow Control
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Solution Overview
Problem
Conventional refrigeration systems with multiple evaporators face challenges in achieving efficient energy use and stability due to the need for precise control of refrigerant flow, especially when operating in cycles and with varying pressure and temperature conditions.
Innovation Solution
A cooling system with multiple parallel evaporators is controlled using a controller that adjusts refrigerant flow based on the superheat of the evaporators, employing valve arrangements to manage inflow and outflow efficiently, allowing for fast switching and stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a valve is opened a predetermined period before the start of the compressor to equalize pressure difference, then the required start torque is reduced, but the control complexity increases
Solution Approach 1:
The valve is opened a predetermined period before the compressor starts to equalize the pressure difference between condenser and evaporator. This preliminary action reduces the pressure differential that the compressor must overcome at startup, thereby reducing the required start torque and improving motor performance during compressor startup.
2Adaptability or versatility
If multiple evaporators operate independently at different temperature ranges and pressure, then cooling versatility is improved, but control stability deteriorates
Solution Approach 1:
Each evaporator is equipped with its own flow control valve that independently controls refrigerant flow to that specific evaporator. This allows each evaporator to operate at its optimal temperature and pressure conditions for its specific cooling requirements, while the centralized controller coordinates their operation to maintain overall system stability.
Solution Approach 2:
The controller receives feedback from temperature and pressure sensors monitoring each evaporator's operation. Based on this feedback, the controller dynamically adjusts the flow control valves to maintain stable operation of multiple evaporators working simultaneously at different conditions, preventing control instability.
3Use of energy by moving object
If the compressor runs in cycles with on and off phases, then energy consumption is reduced, but cooling efficiency deteriorates
Solution Approach 1:
Before the compressor shuts off, the flow control valves are adjusted to optimize refrigerant distribution to the evaporators. This preliminary optimization ensures that maximum cooling efficiency is achieved during the compressor's on-phase, allowing for longer off-periods and reduced overall energy consumption while maintaining adequate cooling performance.
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 enhances cooling efficiency and energy savings by maintaining stable control of refrigerant flow, enabling simultaneous operation of multiple evaporators and improving energy efficiency by optimizing refrigerant distribution based on superheat conditions.
Implementation Method 1
a cooling system with improved cooling efficiency and thereby energy savings can be achieved in a cooling system with multiple parallel evaporators. The cooling system can become stable if the control takes into account the superheat of the evaporator(s).
Data Source
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AI summary
Described is a cooling system comprising a compressor (31), a condenser (32) and at least a first evaporator (34) and a second evaporator (35) connected in parallel with the first evaporator. A refrigerant is circulated in the cooling system. Further a controller (40) is provided and configured to control the flow of refrigerant to and/ or from at least one of said first evaporator and second evaporator based on the superheat of said at least one of the first evaporator and second evaporator. Hereby a control algorithm that is stable and at the same time enables fast switching in the refrigerant flow is achieved.