Inactive Condenser Reheat Circuit for Receiver-Free Charge Storage
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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, 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 by using the auxiliary side connector of an expansion valve and deactivates the main condenser during reheat mode, storing excess refrigerant in the inactive condenser, and controls subcooling levels using simple check valves and a system controller to minimize the use of solenoid valves and dedicated control valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid receiver and associated control valves are added to manage refrigerant charge during reheat mode, then refrigerant charge management is improved, but device complexity and cost increase
Solution Approach 1:
The main condenser is designed to perform multiple functions: it acts as a condenser during cooling mode and as a storage reservoir for excess refrigerant during reheat mode. This eliminates the need for a dedicated liquid receiver, reducing system complexity while maintaining reliable refrigerant charge management.
Solution Approach 2:
The system uses its own existing components (main condenser, expansion valve, check valves) to manage refrigerant charge during mode transitions, rather than requiring external dedicated components. The expansion valve's auxiliary side connector and the condenser work together to automatically regulate refrigerant flow and storage based on operational mode.
2Productivity
If the main condenser is deactivated during reheat mode to store excess refrigerant, then refrigerant charge efficiency is improved, but system complexity increases due to additional valves
Solution Approach 1:
The solution extracts only the essential function needed for mode transition by using a simple check valve to isolate the main condenser during reheat mode, rather than implementing complex active control systems. The check valve passively prevents refrigerant flow to the deactivated condenser, simplifying the control mechanism.
Solution Approach 2:
The auxiliary side connector of the expansion valve serves as an intermediary pathway that allows refrigerant to be directed to or from the main condenser based on operational mode. This intermediary connection enables flexible refrigerant routing using simple passive components rather than complex active control systems.
3Ease of manufacture
If subcooling control is implemented using simple check valves instead of solenoid valves, then device cost is reduced, but control precision may be affected
Solution Approach 1:
The system replaces expensive, complex solenoid valves with simple, inexpensive check valves for subcooling control. While check valves are simpler components, they effectively perform the necessary function of directing refrigerant flow to achieve appropriate subcooling levels without requiring precision electronic control.
Solution Approach 2:
The solution replaces electrically-controlled solenoid valves with purely mechanical check valves that automatically regulate refrigerant flow based on pressure differential. This mechanical substitution eliminates the need for electrical controls while maintaining adequate subcooling control through passive flow regulation.
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 efficiently manages refrigerant charge and subcooling levels, optimizing system performance in both cooling and reheat modes without the need for expensive liquid receivers or complex control systems.
Implementation Method 1
storing excess refrigerant in the inactive condenser
Implementation Method 2
using the auxiliary side connector of an expansion valve
Implementation Method 3
the evaporator cools the air
Implementation Method 4
the evaporator cools the air
Implementation Method 5
a heater downstream of the evaporator raises the temperature of the supply air
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
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 (16) 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 (20), refrigerant can be transferred accordingly between the inactive condenser (16) and the reheat coil (20'). In some embodiments, the system's evaporator (18) and reheat coil '(2O)' can be connected in a series or parallel flow relationship."