Refrigerant Pump Priming via Condenser Decoupling at Startup
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Solution Overview
Problem
In HVAC or refrigeration systems, there is a challenge in ensuring appropriate refrigerant flow and pressure differential during startup, which is crucial for lubricating and cooling moving parts like compressor bearings and motors, especially in systems with multiple chillers where shutting off the condenser water pump is not practical.
Innovation Solution
The system employs a method to prime the refrigerant pump by decoupling the condenser operation using a flow control device, such as a source valve, allowing refrigerant sourcing from both the condenser and evaporator to establish an appropriate pressure differential, enabling efficient lubrication and cooling of compressor components without requiring the condenser water pump to be turned off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the condenser water pump is shut off to prime the refrigerant pump, then liquid refrigerant can be sourced from the evaporator to establish appropriate pressure differential, but this is not practical in systems with multiple chillers and may impact other system areas
Solution Approach 1:
The system is segmented into multiple refrigerant sourcing paths: one from the evaporator (for priming) and one from the condenser (for normal operation). The flow control device on the condenser source line allows selective activation of these paths, enabling the refrigerant pump to be primed from the evaporator without shutting off the condenser water pump, thus resolving the contradiction between priming reliability and system operation flexibility.
2Reliability
If liquid refrigerant is sourced from the evaporator during startup, then appropriate pressure differential can be established for compressor lubrication, but the condenser must be decoupled which complicates system design
Solution Approach 1:
A flow control device acts as an intermediary element on the condenser source line. This device mediates between the condenser and refrigerant pump, allowing the system to selectively connect or disconnect the condenser from the refrigerant pump inlet. During startup, the flow control device closes to decouple the condenser, enabling evaporator-based priming; during normal operation, it opens to allow condenser-based refrigerant supply, thus achieving reliable compressor lubrication without excessive system complexity.
3Ease of operation
If the condenser remains connected during refrigerant pump priming, then system continuity is maintained, but inadequate pressure differential may cause insufficient refrigerant flow to lubricate moving parts
Solution Approach 1:
The flow control device on the condenser source line provides dynamic control over refrigerant flow paths. During startup conditions, the device dynamically closes to decouple the condenser, forcing refrigerant flow exclusively from the evaporator to establish the necessary pressure differential for pump priming and compressor lubrication. During normal operation, it dynamically opens to restore system continuity and allow condenser-based refrigerant supply, thus maintaining both system continuity and reliable lubrication under different operating conditions.
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 approach ensures reliable refrigerant flow and pressure differential during startup, preventing damage to compressor components and maintaining system efficiency across various operating conditions, including startup, restart, full load, and partial load, while allowing the condenser water pump to operate continuously.
Implementation Method 1
there can be an issue of whether the refrigerant pump is primed with a suitable and appropriate pressure differential so as to confirm a refrigerant flow through the refrigerant pump
Implementation Method 2
the compressor can compress refrigerant vapor, and the compressed refrigerant vapor may be directed into the condenser to condense into liquid refrigerant
Implementation Method 3
The liquid refrigerant can then be expanded by the expansion device and directed into the evaporator... The chilled water can then be piped to locations for desired end use(s)
Implementation Method 4
liquid refrigerant can be used as a lubricant for components with moving parts, such as the moving parts of a compressor, including its motor and bearings therein
Data Source
AI summary
Generally, apparatuses, systems, and methods are described to prime a refrigerant pump by decoupling or shielding from a condenser operation, such as for example the condenser water pump, so that liquid refrigerant can be appropriately sourced from the condenser and/or the evaporator using flow control device(s) such as a source valve on a source line of the condenser and/or on a source line of the evaporator and the control of such valve(s).