Powered Subcooler Circuit for High-Ambient HVAC Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing HVAC chiller systems face efficiency and capacity losses, especially at high ambient temperatures, due to the limitations of prior art technologies such as economizers and separate condensers, which require additional compressor losses and increased space, and are not effective with higher-pressure refrigerants like R-410A and carbon dioxide.
Innovation Solution
The implementation of a powered subcooler system with multiple closed refrigerant loops, including a main circuit and subcooler circuits, that exchange heat to cool the refrigerant before entering the evaporator, enhancing cooling capacity and efficiency without the need for complex equipment or wiring, and allowing operation at high ambient temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an economizer is installed to improve thermodynamic cycle efficiency, then efficiency is improved, but compressor efficiency is limited and additional compressor losses occur
Solution Approach 1:
The invention extracts the subcooling function from the main refrigerant circuit by introducing a separate subcooler circuit with its own evaporator. This allows the subcooling process to occur independently without requiring modifications to the compressor or main circuit, thereby avoiding compressor losses while achieving the desired thermodynamic efficiency improvement.
Solution Approach 2:
The subcooler evaporator acts as an intermediary heat exchanger that transfers heat from the main refrigerant circuit to the subcooler refrigerant. This intermediary device enables subcooling of the liquid refrigerant without direct intervention in the compressor operation, avoiding the harmful effect of compressor losses while achieving the beneficial effect of improved cycle efficiency.
2Loss of energy
If separate condensers are used for main circuit and subcooler circuit to achieve subcooling, then subcooling capacity is improved, but space requirements increase
Solution Approach 1:
The invention merges the subcooler condenser with the main circuit condenser, allowing both the main refrigerant circuit and the subcooler circuit to reject heat to the same ambient air stream. This consolidation eliminates the need for separate condenser space while maintaining the subcooling function, as the subcooler condenser utilizes the same airflow path as the main condenser.
3Temperature
If refrigerant is cooled to 32°F to 50°F in subcooler to achieve lower evaporator temperatures, then refrigeration temperatures are achieved, but substantial performance penalty occurs in air conditioning systems
Solution Approach 1:
The invention dynamically adjusts the subcooling level by controlling the operation of the subcooler evaporator and condenser based on ambient conditions and system requirements. Rather than fixed subcooling to 32-50°F, the system optimizes the degree of subcooling to maintain air conditioning performance while achieving sufficient subcooling benefits, allowing the refrigerant temperature to vary within an optimal range rather than being固定在过低温度.
4Reliability
If higher-pressure refrigerants like R-410A are used to replace HCFC-22, then environmental performance is improved, but condenser loses ability to condense at high ambient temperatures approaching critical temperature
Solution Approach 1:
The invention applies preliminary subcooling to the liquid refrigerant before it enters the expansion device, which lowers its temperature and increases its density. This preliminary action allows the refrigerant to better absorb heat in the evaporator, compensating for the reduced condensing ability at high ambient temperatures and maintaining system efficiency when using higher-pressure refrigerants like R-410A.
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
The powered subcooler system provides increased cooling capacity and efficiency, reduces fan noise, and allows for smaller condenser coils, while maintaining or reducing costs, and offers additional control over subcooler capacity, leading to energy savings and improved performance at high ambient temperatures.
Implementation Method 1
The subcooler evaporator is arranged and disposed to exchange heat between liquid refrigerant in the main circuit and the refrigerant in the subcooler circuit to cool the liquid refrigerant in the main circuit
Data Source
AI summary
An HVAC system having a main circuit and a subcooler circuit. The main circuit includes a main circuit evaporator, a main circuit expansion device, a main circuit condenser and a main circuit compressor connected in a closed refrigerant loop. The subcooler circuit includes a subcooler evaporator, a subcooler expansion device, a subcooler condenser and a subcooler compressor connected in a closed refrigerant loop. The subcooler evaporator is arranged and disposed to exchange heat between liquid refrigerant in the main circuit and the refrigerant in the subcooler circuit to cool the liquid refrigerant in the main circuit prior to entering the main circuit evaporator. The operation of the subcooler circuit provides an increased cooling capacity per unit of a mass flow of cooling fluid through the main circuit condenser and subcooler condenser for the HVAC system with a predetermined design efficiency.