Heat source unit and refrigeration apparatus
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Solution Overview
Problem
The refrigeration apparatus described in JP 2019 66086A experiences abnormal internal pressure in the receiver due to refrigerant evaporation when the compressor is stopped, leading to increased pressure issues.
Innovation Solution
A heat source unit with a heat source controller that communicates the compression element's inlet with the receiver and drives it to lower the pressure by allowing refrigerant to move from the receiver to the compression element, using a gas passage and on-off valve, and further supplies the refrigerant to the heat source heat exchanger, utilizing a connection passage and expansion valve to manage pressure effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compressor is stopped during operation, then power consumption is reduced, but the pressure in the receiver increases due to refrigerant evaporation
Solution Approach 1:
The control unit monitors receiver pressure even when the compressor is stopped and initiates a pressure reduction operation when pressure exceeds the threshold. This preliminary monitoring and responsive action prevents abnormal pressure accumulation before it becomes dangerous, resolving the contradiction by enabling safe compressor shutdown while maintaining pressure control through on-demand operation.
Solution Approach 2:
The system implements a feedback mechanism where the control unit continuously monitors receiver pressure and compares it against a predetermined threshold. When pressure exceeds the threshold, the control unit activates the compressor to reduce pressure, then stops it again. This closed-loop feedback control allows the system to minimize power consumption while maintaining safe pressure levels through responsive, condition-based operation.
2Reliability
If the compressor is frequently started to reduce receiver pressure, then pressure control is improved, but wear on the compression element increases
Solution Approach 1:
The control unit implements partial action by only operating the compressor when absolutely necessary - specifically when receiver pressure exceeds the predetermined threshold. Rather than continuous operation or frequent cycling, the system applies minimal necessary compression action to maintain safety, thereby extending compression element service life while ensuring adequate pressure control through threshold-based triggering.
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 effectively lowers the pressure in the receiver, preventing abnormal conditions and reducing the risk of damage, while also optimizing power consumption by driving a single compressor during the first operation.
Implementation Method 1
a compression element (20), a heat source heat exchanger (40), and a receiver (41)
Implementation Method 2
a heat source heat exchanger (40)
Implementation Method 3
an expansion valve (44) provided in the connection passage (P2)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A heat source controller (14) performs a first operation when a compression element (20) is in a stopped state and a pressure (RP) in a receiver (41) exceeds a predetermined first pressure (Pth1). The heat source controller (14) allows an inlet of the compression element (20) to communicate with the receiver (41), and drives the compression element (20) in the first operation.