Refrigerant Reheat Circuit for Target Subcooling Charge Control
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Solution Overview
Problem
Conventional refrigerant systems face inefficiencies in refrigerant charge management during reheat mode, leading to either excessive or insufficient refrigerant, which affects system efficiency in both cooling and reheat modes, and existing solutions are costly due to the need for additional components like liquid receivers and complex control valves.
Innovation Solution
A refrigerant system that adjusts its effective charge using the auxiliary side connector of an expansion valve, monitors and controls subcooling by sensing refrigerant temperatures, and selectively deactivates the main condenser or reheat coil to switch between cooling and reheat modes, minimizing the use of solenoid valves and using a shared heat exchanger for both functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid receiver is added to store excess refrigerant during reheat mode, then refrigerant charge control is improved, but system cost and complexity increase
Solution Approach 1:
The patent makes the condenser serve dual functions: acting as a heat rejection device during cooling mode and as a refrigerant storage receiver during reheat mode. This eliminates the need for a separate liquid receiver component, reducing system complexity while maintaining proper refrigerant charge control during mode transitions
Solution Approach 2:
The patent combines the cooling function and refrigerant storage function into a single condenser component. By merging these functions, the system avoids adding separate receivers and associated control valves, thereby reducing both cost and complexity while solving the refrigerant charge management problem
2Adaptability or versatility
If an additional heat exchanger is added for reheat mode, then reheat functionality is improved, but refrigerant charge management becomes problematic
Solution Approach 1:
The condenser is designed to perform multiple functions: heat rejection during cooling mode and refrigerant storage during reheat mode. This multi-functionality allows the system to handle both cooling and reheat operations while automatically managing refrigerant charge distribution, eliminating the refrigerant management problems associated with additional heat exchangers
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 allows for a simpler, cost-effective refrigerant system that maintains optimal refrigerant charge and subcooling levels, enhancing efficiency and reducing costs by eliminating the need for expensive receivers and complex control systems.
Implementation Method 1
a reheat coil that heats the refrigerant by placing the reheat coil in heat exchange relationship with the stream of air
Implementation Method 2
an evaporator that cools the stream of air to a temperature below a dew point of the stream of air
Implementation Method 3
a compressor that exits a compressor at a pressure and a temperature
Data Source
AI summary
A refrigerant system for cooling a comfort zone is selectively operable in a cooling-only mode and a reheat mode. The system operates in the cooling mode to meet sensible and latent cooling demands of a room or area in a building when the room temperature is appreciably above a target temperature. The reheat mode is for addressing the latent cooling or dehumidifying demand when the room temperature is near or below the target temperature. In some embodiments, a generally inactive condenser stores excess refrigerant during the reheat mode, thereby avoiding the need for a separate liquid refrigerant receiver. To maintain a desired level of subcooling in the reheat coil, refrigerant can be transferred accordingly between the inactive condenser and the reheat coil. In some embodiments, the system's evaporator and reheat coil can be connected in a series or parallel flow relationship.