Evaporator-Fed Refrigerant Lubrication for Compressor Startup
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Solution Overview
Problem
HVAC and refrigeration systems face challenges in ensuring appropriate refrigerant flow and lubrication to moving parts during startup, particularly in systems with multiple chillers, where shutting off the condenser water pump is not practical, risking damage to compressor components due to inadequate refrigerant cooling and lubrication.
Innovation Solution
A refrigerant cooling and lubrication assembly that sources liquid refrigerant from the evaporator during startup, using pressure transducers to establish a suitable pressure differential, and then transitions to sourcing from the condenser once the compressor is operational, employing solenoid valves controlled by a unit controller to manage refrigerant flow and decouple the condenser during startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the condenser water pump is shut off to prime the refrigerant pump, then refrigerant flow and pressure differential are established, but system complexity increases and operation becomes impractical in multi-chiller systems
Solution Approach 1:
The patent introduces an intermediary mechanism (check valve and evaporator access arrangement) that enables automatic refrigerant pump priming without requiring condenser water pump shutdown. The check valve acts as a mediator to prevent backflow and maintain pressure differential, while the evaporator access provides a pathway for liquid refrigerant to reach the pump inlet, solving the contradiction between reliable priming and operational simplicity.
2Quantity of substance
If liquid refrigerant is sourced from the condenser during startup, then refrigerant flow is available, but pressure differential may be insufficient to ensure proper flow through the refrigerant pump
Solution Approach 1:
The patent applies preliminary action by arranging the evaporator access and check valve to automatically establish the necessary pressure differential before the refrigerant pump starts. Liquid refrigerant from the evaporator is positioned to flow into the pump inlet, creating the required suction pressure condition in advance, ensuring proper pump operation from startup.
3Object-generated harmful factors
If the system uses oil lubrication for moving parts, then lubrication is provided, but refrigerant cooling capability is reduced
Solution Approach 1:
The patent implements multi-functionality by configuring the refrigerant distribution system to serve dual purposes: the refrigerant acts as both a cooling medium for temperature control and as a lubricant for moving parts. This is achieved through strategic placement of refrigerant outlets near compressor bearings and motor components, allowing the same refrigerant flow to perform both lubrication and cooling functions simultaneously.
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
Ensures reliable refrigerant flow and lubrication to compressor components, preventing damage and maintaining system efficiency by priming the refrigerant pump and establishing a stable pressure differential before starting the compressor, even in systems with multiple chillers where condenser water pumps cannot be shut off.
Implementation Method 1
establish a suitable pressure differential, and then transitions to sourcing from the condenser once the compressor is operational
Implementation Method 2
employing solenoid valves controlled by a unit controller to manage refrigerant flow
Implementation Method 3
liquid refrigerant can be used as a lubricant for components with moving parts, such as the moving parts of a compressor
Implementation Method 4
cool and lubricate such moving parts that may be part of the compressor
Implementation Method 5
refrigerant flow through the refrigerant pump line
Data Source
AI summary
Generally, apparatuses, systems, and methods are described that are directed to accessing liquid refrigerant from an evaporator to source a refrigerant pump and pump line to cool and lubricate such moving parts that may be part of the compressor, for example the compressor motor and the compressor bearings, and/or for cooling drives such as an adjustable or variable frequency drive.