Suction Heat Exchanger as Receiver for Low-GWP Lubricant Separation
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Solution Overview
Problem
HVACR systems using low-GWP working fluids often experience poor separation of working fluids and lubricants due to reduced waste heat generation and inefficient compressor efficiency, leading to suboptimal performance.
Innovation Solution
Incorporating a suction heat exchanger that increases the temperature of the working fluid before it enters the compressor, thereby enhancing discharge superheat and improving lubricant separation, while also functioning as a dynamic receiver to control the working fluid charge based on operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If low-GWP working fluids are used, then environmental impact is reduced, but separation of working fluid and lubricant deteriorates
Solution Approach 1:
The patent changes the temperature parameter of the suction gas by incorporating a heat exchanger that heats the working fluid before it enters the compressor. This temperature parameter change increases discharge superheat, which improves the separation of low-GWP working fluids from lubricants while maintaining environmental benefits
Solution Approach 2:
The suction heat exchanger acts as an intermediary component between the evaporator and compressor, introducing a thermal mediation process that modifies the working fluid properties to enable better lubricant separation without changing the fundamental low-GWP fluid choice
2Use of energy by moving object
If compressor efficiency is improved, then energy consumption is reduced, but waste heat generation decreases leading to poor working fluid separation
Solution Approach 1:
The patent converts the harmful effect of insufficient waste heat (caused by high compressor efficiency) into a benefit by deliberately adding heat through the suction heat exchanger. This external heating compensates for the reduced waste heat while maintaining or improving overall system efficiency
Solution Approach 2:
By changing the temperature parameter of the suction gas through external heating, the system compensates for reduced waste heat generation from efficient compressors, ensuring adequate discharge superheat for proper working fluid-lubricant separation
3Reliability
If discharge superheat is increased, then lubricant separation is improved, but energy input to the system increases
Solution Approach 1:
The suction heat exchanger uses waste heat from the system (heat from the working fluid after the condenser) to heat the suction gas, making the heating process self-sufficient without requiring external energy input. The system essentially uses its own waste resources to achieve the desired temperature increase
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 enhances lubricant separation and improves overall HVACR system performance by increasing discharge superheat and allowing for tailored working fluid circulation, optimizing system efficiency even with low-GWP fluids.
Implementation Method 1
heating the working fluid leaving the evaporator prior to the working fluid entering a suction of a compressor... exchanging heat between the working fluid leaving the evaporator and a flow of the working fluid obtained from the circuit between the lubricant separator and the condenser at a heat exchanger
Implementation Method 2
compressor having a suction and a discharge... heating the working fluid increases a discharge superheat of the compressor
Data Source
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AI summary
A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a suction heat exchanger configured to add heat to working fluid prior to entering the compressor, so as to support the generation of superheat by the HVACR system. The superheat can be controlled to achieve desired levels, so as to support the separation of lubricant from working fluid of the HVACR system. The suction heat exchanger can heat the working fluid passing to the suction of the compressor by exchanging heat with working fluid sourced from between the lubricant separator and the condenser. The suction heat exchanger can further be used as a receiver for controlling the charge of working fluid circulating in the HVACR system.