Vapor compression system and method for vapor oil recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vapor compression systems face challenges in maintaining proper oil viscosity at low compressor loads, which affects reliable operation, especially with the introduction of variable speed drive technology, as existing solutions like copper line bypasses are not fully effective in optimizing oil recovery and efficiency.
Innovation Solution
A vapor compression system with a heat recovery heat exchanger and a controlled bypass system, where a high-pressure vapor refrigerant from the condenser is directed to a vaporizer and then through a bypass valve to the evaporator, allowing for higher viscosity oil output and increased efficiency by managing compressor speed reduction and load variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a compressor operates at low load and low speed to match cooling demands, then energy efficiency is improved, but oil viscosity deteriorates making oil recovery more difficult
Solution Approach 1:
The system performs preliminary heating of the refrigerant-oil mixture in the vaporizer using high-pressure vapor refrigerant from the condenser before the mixture enters the evaporator. This preliminary action ensures that oil viscosity is maintained at appropriate levels even when the compressor operates at low speeds, preventing oil recovery problems while allowing energy-efficient low-load operation.
Solution Approach 2:
The vaporizer acts as an intermediary component between the condenser and evaporator. It receives high-pressure vapor refrigerant from the condenser, mixes it with liquid refrigerant and oil, and provides heated vapor-phase refrigerant-oil mixture to the evaporator. This intermediary process enables controlled heating and phase transformation that maintains oil viscosity during low-load operation.
2Reliability
If a copper line bypass is used to allow high pressure vapor refrigerant to flow from condenser to evaporator, then oil recovery is improved, but system complexity and energy efficiency are compromised
Solution Approach 1:
The vaporizer performs multiple functions: it heats the refrigerant-oil mixture using condenser vapor, controls phase transformation, regulates oil viscosity, and enables controlled flow to the evaporator. This multi-functional component achieves oil recovery improvement while also contributing to energy efficiency through heat recovery, avoiding the need for separate dedicated bypass systems.
Solution Approach 2:
The system changes the temperature and phase parameters of the refrigerant-oil mixture by heating it in the vaporizer. This parameter change transforms the mixture into a vapor phase with controlled temperature and viscosity, enabling effective oil recovery while maintaining system efficiency through controlled thermal processes.
3Reliability
If high pressure vapor refrigerant is directed to a heat recovery heat exchanger (vaporizer) instead of direct bypass, then oil viscosity is improved, but additional equipment is required
Solution Approach 1:
The vaporizer serves multiple purposes: heating the refrigerant-oil mixture, controlling phase transformation, regulating oil viscosity, and enabling controlled flow distribution. By combining these functions in a single component, the system achieves improved oil viscosity management without requiring multiple separate equipment pieces for each function.
Solution Approach 2:
The vaporizer uses the high-pressure vapor refrigerant from the condenser as a self-contained heat source to heat the refrigerant-oil mixture. This self-service approach eliminates the need for external heating devices or additional energy input systems, achieving the heating function through internal system resources.
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 enables more efficient compressor operation at varying loads by maintaining optimal oil viscosity and reducing energy consumption, enhancing the overall performance and reliability of the vapor compression system.
Implementation Method 1
directing a high pressure, high temperature vapor refrigerant from a condenser to a heat recovery heat exchanger, such as a vaporizer
Implementation Method 2
A heat recovery heat exchanger receives a first phase from a first heat exchanger and directs the first phase through a controlled bypass system to a second heat exchanger
Implementation Method 3
a bypass valve that opens when a compressor operating load capacity is less than a predetermined compressor operating load capacity limit
Data Source
Figure 1
Figure 2
AI summary
A vapor compression system 100 including: a compressor 10 having a compressor suction port 110 and a compressor discharge port 112 configured to circulate a working fluid through a flow circuit; a first heat exchanger 20 operably coupled to the compressor discharge port 112; a second heat exchanger 30 operably coupled to the compressor suction port 110; a heat recovery heat exchanger 40 operably coupled to the first and second heat exchangers 20, 30 wherein the heat recovery heat exchanger 40 is configured to: receive the working fluid in a first phase from the first heat exchanger 20; receive the working fluid in a second phase from the second heat exchanger 30; exchange heat between the working fluid in the first phase and the second phase; and a bypass valve 66 positioned between the heat recovery heat exchanger 40 discharge and the second heat exchanger 30 and defining a first flow path 62 and a second flow path 69.