Heat source-side unit and refrigeration apparatus
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Solution Overview
Problem
Existing refrigeration apparatuses face challenges in preventing liquid compression during startup, which can damage compressors due to the suction of liquid refrigerant, especially when the refrigerant is stored in utilization-side units.
Innovation Solution
The refrigeration apparatus incorporates a control unit that performs a liquid compression avoidance action by stopping the lower-stage compressors and operating the higher-stage compressor, with the intermediate heat exchanger functioning as an evaporator to evaporate liquid refrigerant before it is compressed by the first compressor, and adjusts operations based on suction pressure values to prevent liquid compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the lower-stage compression element operates at startup, then the compression unit can compress refrigerant efficiently, but liquid refrigerant may be compressed causing damage
Solution Approach 1:
The control unit performs preliminary detection of suction pressure before startup compression. When suction pressure exceeds the predetermined value, the system preemptively stops the lower-stage compression element to prevent liquid compression, ensuring safe operation before compression begins
Solution Approach 2:
The system dynamically adjusts compressor operation based on real-time suction pressure conditions. The lower-stage compression element is selectively activated or deactivated depending on whether suction pressure is above or below the predetermined threshold, optimizing both safety and efficiency
2Power
If the intermediate heat exchanger is used for heat exchange, then heating efficiency is improved, but the refrigerant path becomes more complex
Solution Approach 1:
The intermediate heat exchanger serves multiple functions: it acts as a heat exchanger for heating operations and simultaneously functions as an evaporator to vaporize liquid refrigerant during startup conditions, reducing the need for separate dedicated components
Solution Approach 2:
The patent combines the heat exchange function and refrigerant vaporization function into a single intermediate heat exchanger component, integrating multiple functions into one element to manage system complexity
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 effectively prevents liquid compression at startup, ensuring the compressor operates safely and efficiently by evaporating liquid refrigerant before compression, thus avoiding damage and ensuring smooth operation.
Implementation Method 1
an intermediate heat exchanger (17) disposed on a refrigerant path between the lower-stage compression element (23) and the higher-stage compression element (21) and configured to cause the refrigerant to exchange heat with a heating medium
Data Source
AI summary
A heat source-side unit (10) includes a heat source-side circuit (11). The heat source-side circuit (11) includes a compression unit (20) including a lower-stage compression element (23) and a higher-stage compression element (21), an intermediate heat exchanger (17) disposed on a refrigerant path between the lower-stage compression element (23) and the higher-stage compression element (21), and a bypass passage (23c) connected to a suction pipe (23a) and a discharge pipe (23b) each connected to the lower-stage compression element (23). At startup of the compression unit (20), a first action is performed for stopping the lower-stage compression element (23) and operating the higher-stage compression element (21). This configuration thus suppresses occurrence of liquid compression at startup of a compressor.