DX Cooling Capacity Control Using Receiver Tank Gas Bypass
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Solution Overview
Problem
Prior direct expansion (DX) cooling systems face challenges in controlling cooling capacity and energy efficiency, particularly at lower cooling capacities, due to suboptimal refrigerant flow and distribution, leading to inefficient heat transfer and potential freezing issues.
Innovation Solution
The DX cooling system incorporates a receiver tank, evaporator, compressor, and gas cooler connected by conduits with pressure and gas flow regulators, allowing for precise control of refrigerant flow by adjusting the gas flow regulator to mix gaseous and liquid refrigerants before entering the evaporator, optimizing refrigerant distribution and pressure conditions for improved cooling capacity and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional expansion valve control is used in prior DX cooling systems, then the system structure is simple, but the cooling capacity control is suboptimal particularly at lower capacities
Solution Approach 1:
The gas outlet of the receiver tank is connected to the evaporator inlet via a fifth conduit and gas flow regulator, enabling the receiver tank to serve dual purposes: storing liquid refrigerant and providing a gas phase refrigerant source. This multi-functional approach allows flexible control of refrigerant flow to the evaporator, improving cooling capacity control without adding substantial system complexity
Solution Approach 2:
The gas flow regulator acts as an intermediary device between the receiver tank and evaporator, mediating the refrigerant flow control. By regulating gas phase refrigerant flow from the receiver tank to the evaporator, it enables precise cooling capacity control, particularly at lower capacities, while maintaining system structural simplicity
2Ease of operation
If additional expansion valves are added to control refrigerant flow, then the cooling capacity control improves, but the device complexity increases
Solution Approach 1:
The existing expansion valve is made multi-functional by connecting it to both liquid outlet and gas outlet pathways. The expansion valve can regulate both liquid refrigerant flow from the receiver tank and gas phase refrigerant flow, eliminating the need for separate gas flow control valves and maintaining device simplicity while achieving superior cooling capacity control
Solution Approach 2:
The liquid and gas refrigerant pathways are merged at the evaporator inlet, where both liquid refrigerant from the first conduit and gas phase refrigerant from the fifth conduit can enter the evaporator. This merging allows flexible combination of refrigerant phases to optimize cooling capacity control without requiring additional separate control valves
3Productivity
If liquid refrigerant flow is increased to the evaporator, then the cooling capacity increases, but the risk of freezing issues and inefficient heat transfer increases at lower capacities
Solution Approach 1:
The system provides different refrigerant phase qualities to different locations: liquid refrigerant is supplied to the evaporator inlet via the first conduit for primary cooling, while gas phase refrigerant is supplied via the fifth conduit to supplement cooling and prevent freezing. This local quality differentiation ensures optimal heat transfer efficiency and reliability across varying cooling capacity requirements
Solution Approach 2:
The system changes the physical parameter of refrigerant phase by providing both liquid and gas phase refrigerant to the evaporator. The gas flow regulator controls the proportion of gas phase refrigerant, allowing dynamic adjustment of refrigerant parameters to match cooling demand, preventing freezing while maintaining efficient heat transfer
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 configuration enhances cooling capacity control, improves energy efficiency, and ensures optimal refrigerant utilization, minimizing the need for additional expansion valves and preventing freezing issues, while maintaining cost-effectiveness and efficient heat transfer.
Implementation Method 1
at least one of the first conduit and the fourth conduit comprises a pressure regulator
Implementation Method 2
the gas outlet of the receiver tank is connected to the evaporator inlet via a fifth conduit and a gas flow regulator, such that a flow of gaseous refrigerant from the receiver tank may enter the evaporator during use
Implementation Method 3
the evaporator comprises an evaporator inlet and an evaporator outlet
Implementation Method 4
the compressor comprises a compressor inlet and a compressor outlet
Implementation Method 5
the gas cooler comprises a cooler inlet and a cooler outlet
Data Source
AI summary
The present invention provides a cooling system (1), comprising a receiver tank (2), an evaporator (3), a compressor (4) and a gas cooler (5), wherein the receiver tank (2) comprises a fluid inlet (6), a liquid outlet (7) and a gas outlet (8); the evaporator (3) comprises an evaporator inlet (9) and an evaporator outlet (10), the compressor (4) comprises a compressor inlet (11) and a compressor outlet (12); the gas cooler (5) comprises a cooler inlet (13) and a cooler outlet (14); and the liquid outlet (7) of the receiver tank (2) is connected to the evaporator inlet (9) via a first conduit (15), the evaporator outlet (10) is connected to the compressor inlet (11) via a second conduit (16), the compressor outlet (12) is connected to the cooler inlet (13) via a third conduit (17), and the cooler outlet (14) is connected to the fluid inlet (6) of the receiver via a fourth conduit (18), wherein at least one of the first conduit (15) and the fourth conduit (18) comprises a pressure regulator (19,25), and the gas outlet (8) of the receiver tank is connected to the evaporator inlet (9) via a fifth conduit (20) and a gas flow regulator (21,22), such that a flow of liquid refrigerant in the first conduit (15) may be controlled by operating the gas flow regulator (21,22) during use.