Multistage Refrigeration Flow Switching for Stable Heating
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Solution Overview
Problem
In refrigeration apparatuses with multistage compression, uneven refrigerant flow occurs during heating operations due to pressure differences across heat-source-side heat exchangers, leading to inadequate performance as evaporators.
Innovation Solution
A refrigeration apparatus with a multistage compression mechanism, heat-source-side main and sub heat exchangers, and a refrigerant piping group that connects these in series during heating operations, ensuring even refrigerant distribution and flow through multiple heat exchangers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heat-source-side sub heat exchangers are designed to emphasise performance for cooling operation, then cooling performance is improved, but refrigerant flow distribution becomes uneven during heating operation
Solution Approach 1:
The patent employs switching mechanisms (valves) to dynamically change the refrigerant flow path configuration between cooling and heating operations. During cooling, sub heat exchangers are connected in parallel for high performance; during heating, they are reconfigured to connect in series, ensuring uniform refrigerant distribution. This dynamic reconfiguration allows each heat exchanger to be optimized for cooling while maintaining reliable operation during heating.
2Productivity
If refrigerant flows in parallel through multiple heat-source-side heat exchangers during heating operation, then heat exchange capacity increases, but uneven flow occurs due to pressure differences
Solution Approach 1:
The system dynamically switches between parallel and series configurations of heat exchangers based on operational mode. During heating, the switching mechanisms reconfigure the flow path so refrigerant passes through sub heat exchangers in series, ensuring uniform distribution while maintaining adequate heat exchange capacity through the coordinated operation of all heat exchangers in the series path.
3Measurement precision
If electronic valves or capillary tubes are used to adjust flow distribution, then flow control precision improves, but device complexity and cost increase
Solution Approach 1:
The patent uses switching mechanisms (valves) to dynamically reconfigure the refrigerant flow path between parallel and series connections based on operational mode. This approach achieves flow distribution control through mechanical reconfiguration rather than continuous adjustment devices, reducing complexity while maintaining effective control over refrigerant distribution during heating operations.
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 suppresses uneven refrigerant flow, ensuring each heat exchanger functions effectively as an evaporator during heating, maintaining efficient operation and reducing production costs.
Implementation Method 1
The heat-source-side main heat exchanger functions as a radiator during the cooling operation, and functions as an evaporator during the heating operation
Implementation Method 2
the expansion mechanism, during the cooling operation, depressurizes the refrigerant delivered from the heat-source-side main heat exchanger to the usage-side heat exchanger
Implementation Method 3
the expansion mechanism, during the cooling operation, depressurizes the refrigerant delivered from the heat-source-side main heat exchanger to the usage-side heat exchanger
Implementation Method 4
a multistage compression mechanism having one low-stage compression part and a plurality of high-stage compression parts
Data Source
AI summary
A refrigeration apparatus includes a multistage compression mechanism, a heat-source-side main heat exchanger, at least one heat-source-side sub heat exchanger, a usage-side heat exchanger, a switching mechanism, an expansion mechanism and a refrigerant piping group. The refrigerant piping group connects the multistage compression mechanism, the switching mechanism, the heat-source-side main heat exchanger, the heat-source-side sub heat exchanger, the expansion mechanism and the usage-side heat exchanger so that during the heating operation, the heat-source-side main heat exchanger and the heat-source-side sub heat exchanger are connected in series.