Economizer Refrigeration Circuit With Independent Pressure Control
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Solution Overview
Problem
Conventional refrigeration systems with economizer circuits lack independent control over economizer operating pressure and flow rate, leading to compromised performance under off-design conditions, especially when using single-stage compressors, which restricts the use of certain compressor types and requires multiple compression stages.
Innovation Solution
Incorporating an auxiliary compressor that is independently controllable, allowing for independent control of economizer pressure and flow rate, enabling optimal operation by matching discharge pressures and adjusting lift and capacity to maintain optimal economizer conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flash tank economizer circuit is used with single-stage compressors, then the system can incorporate an economizer, but the economizer operating conditions are dictated by overall system conditions and cannot be independently controlled
Solution Approach 1:
The invention divides the compression function into two separate compressors: a main compressor for the primary refrigeration cycle and an auxiliary compressor dedicated to the economizer circuit. This segmentation allows independent control of economizer operating conditions through the auxiliary compressor while the main compressor handles the overall system refrigeration load.
2Adaptability or versatility
If multiple compression stages are used to incorporate an economizer, then economizer circuit functionality is achieved, but device complexity increases
Solution Approach 1:
Instead of using multiple compression stages in a single compressor, the invention segments the compression function across two separate single-stage compressors. The main compressor handles the evaporator to condenser compression, while the auxiliary compressor handles the economizer vapor compression, eliminating the need for complex multi-stage compression mechanisms.
Solution Approach 2:
The auxiliary compressor acts as an intermediary device that receives vapor from the economizer and compresses it to condenser pressure, then discharges it to the condenser. This intermediary compressor simplifies the overall system by avoiding the need for integrated multi-stage compression while achieving the same functional result.
3Device complexity
If economizer flow is integrated into the main compressor, then system integration is improved, but independent control of economizer pressure and flow rate is lost
Solution Approach 1:
The invention segments the compression functions by dedicating the auxiliary compressor solely to economizer vapor compression while the main compressor handles the primary refrigeration cycle. This segmentation enables independent control of economizer pressure and flow rate through the auxiliary compressor without compromising system integration, as the two compressors are connected through the shared condenser and refrigerant lines.
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 solution enables independent control of economizer pressure, optimizing system performance and power savings, allowing the use of compressor types disfavored in conventional systems, and reducing liquid carry-over, thereby enhancing overall refrigeration system efficiency.
Implementation Method 1
an auxiliary compressor to compress gaseous refrigerant leaving the economizer to condenser pressure
Implementation Method 2
the liquid refrigerant experiences a substantial pressure drop, whereupon, at least a portion of the refrigerant rapidly expands or 'flashes' and is converted from a liquid phase to a vapor phase
Implementation Method 3
a refrigerant gas is compressed by a compressor and passed to a condenser where it exchanges heat with another fluid such as the ambient air
Implementation Method 4
the pressurized liquid refrigerant passes through an expansion device and then to an evaporator, where it exchanges heat with another fluid that is used to cool an environment
Data Source
Figure 1~5
Figure 2
Figure 3
AI summary
An economized refrigeration system includes a main refrigerant circuit having a condenser (12), an evaporator (16), an economizer (14), an expansion device (32) intermediate the condenser and the economizer, and a main-compressor (18) fluidly connected by a main refrigerant line (24). The system also includes an economized refrigerant circuit including an auxiliary compressor system (20) and an auxiliary refrigerant line (22) fluidly connecting the economizer (14) to the auxiliary compressor system (20) and fluidly connecting the main refrigerant line (24) to the auxiliary compressor (20) at a location intermediate the main compressor system (18) and the condenser (12). The auxiliary compressor system (20) is independently controllable with respect to the main compressor system (18).