Two-Stage Heat Pump Compression with Compressor Bypass Control
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Solution Overview
Problem
Existing heat pump devices face issues with refrigerant flow and pressure management, particularly when transitioning between single-stage and two-stage compression modes, leading to potential fluid accumulation and inefficient operation.
Innovation Solution
A heat pump device with a refrigeration circuit featuring two compressors connected in series, bypass lines with check valves, and an oil equalization valve, allowing for independent operation of compressors and preventing fluid backflow, ensuring efficient operation in both single-stage and two-stage compression modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two compressors are connected in series for two-stage compression, then compression efficiency is improved, but device complexity increases
Solution Approach 1:
The system dynamically switches between single-stage and two-stage compression modes based on operational requirements. The first compressor can operate independently or in series with the second compressor, allowing the system to adapt its complexity level to match the cooling/heating load demands.
Solution Approach 2:
The first compressor serves multiple functions: it can operate alone for single-stage compression or work in series with the second compressor for two-stage compression. The bypass line and shut-off valve enable the first compressor to handle both single-stage and intermediate cooling functions, reducing the need for dedicated components.
2Adaptability or versatility
If bypass lines are added for independent compressor operation, then operational flexibility is improved, but device complexity increases
Solution Approach 1:
The refrigeration circuit is segmented into separate pathways for each compressor, with the first compressor having its own bypass line and the second compressor having its own bypass line. This segmentation allows independent operation of either compressor while maintaining system functionality through dedicated return paths.
3Reliability
If check valves are installed to prevent fluid backflow, then reliability is improved, but device complexity increases
Solution Approach 1:
Check valves are installed at critical junction points where fluid flow direction needs to be controlled. The check valve in the first bypass line prevents refrigerant from flowing into the first compressor during two-stage compression, while the check valve in the second bypass line prevents fluid backflow into the second compressor during single-stage operation.
4Reliability
If oil separators are added for each compressor, then compressor reliability is improved, but device complexity increases
Solution Approach 1:
The oil separation function is segmented and dedicated to each compressor with individual oil separators. The first oil separator is connected to the first compressor via a first oil line, and the second oil separator is connected to the second compressor via a second oil line, ensuring each compressor has its own oil return path.
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
Enables flexible operation between single-stage and two-stage compression, preventing fluid accumulation and ensuring efficient heat transfer by allowing independent compressor operation and oil equalization, enhancing the overall performance and reliability of the heat pump system.
Implementation Method 1
a first compressor (C1) and a second compressor (C2) connected in series by a line segment (100) such that the compression is two-stage compression if the first compressor C1 and the second compressor C2 operate together
Implementation Method 2
a condenser (2), an evaporator (3), and an expansion valve (19) arranged upstream of the evaporator (3)
Implementation Method 3
a condenser (2), an evaporator (3), and an expansion valve (19) arranged upstream of the evaporator (3)
Implementation Method 4
Both chillers and heat pumps use the same principle, namely that the fluids used have different boiling or condensation temperatures at different pressures and that these fluids cool down when they expand (throttling)
Implementation Method 5
a first oil separator located downstream of the first compressor and connected to the first compressor via a first oil line for returning separated oil to the first compressor, and a second oil separator located downstream of the second compressor
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a heat pump device having a first compressor (C1) and a second compressor (C2) connected in series by a pipe segment (100) such that the compression is two-stage compression if the first compressor ( C1) and the second compressor (C2), a condenser (2), an evaporator (3), an expansion valve (19) arranged upstream of the evaporator (3), a first oil separator (25), located downstream of the first compressor (C1) and connected to the first compressor (C1) via a first oil line (101) for returning separated oil to the first compressor (C1), and a second oil separator (26) which located downstream of the second compressor (C2) and connected to the second compressor (C2) via a second oil line (102) for returning separated oil to the second compressor (C2), at least d he first compressor (C1) or the second compressor (C2) can be operated independently. The non-operating first compressor (C1) or the non-operating second compressor (C2) can be bypassed by a first bypass line (122) or a second bypass line (123). A shut-off valve (27) is connected upstream of the second compressor (C2) in the direction of flow.