Partitioned Evaporator Circuits for HVAC Dehumidification
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Solution Overview
Problem
Existing HVAC systems face challenges in dehumidification, particularly overcooling, which requires additional equipment and energy for reheat coils or uneven refrigerant distribution in existing methods, leading to inefficiencies and increased energy usage.
Innovation Solution
A closed refrigerant loop system with a partitioned evaporator arrangement that includes multiple circuits and a distributor for uniform refrigerant distribution, allowing isolation of certain circuits during dehumidification to prevent overcooling and reheat air without a separate reheat coil, thereby optimizing dehumidification and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an evaporator is used for dehumidification, then moisture is removed from air, but air temperature is reduced excessively (overcooling)
Solution Approach 1:
The evaporator is divided into multiple independent circuits (first circuit and second circuit) that can be selectively activated. During dehumidification mode, only the second circuit is activated to provide gentle cooling and dehumidification, while the first circuit remains inactive. This segmentation allows control over the total cooling capacity to prevent overcooling while maintaining dehumidification effectiveness.
2Temperature
If a reheat coil is added to correct overcooling, then air temperature is increased to desired level, but system complexity and energy consumption increase
Solution Approach 1:
The evaporator circuits are designed to serve multiple functions: during cooling mode, both circuits operate together for maximum cooling capacity; during dehumidification mode, only the second circuit operates to provide gentle cooling and dehumidification without overcooling. This multi-functionality eliminates the need for a separate reheat coil, as the same evaporator components can be selectively configured to achieve both cooling and dehumidification objectives.
3Quantity of substance
If refrigerant flow is increased to enhance dehumidification, then moisture removal improves, but air temperature drops further (exacerbating overcooling)
Solution Approach 1:
The evaporator is segmented into multiple circuits with independent refrigerant flow paths. During dehumidification, only the second circuit receives refrigerant flow, limiting the total amount of refrigerant involved in the heat exchange process. This controlled refrigerant distribution enables effective dehumidification while preventing excessive cooling that would waste energy.
4Device complexity
If a single liquid header distributes refrigerant across all circuits, then refrigerant distribution is simplified, but uneven phase distribution occurs in the evaporator
Solution Approach 1:
The evaporator is divided into separate circuits (first and second circuits) with independent refrigerant distribution paths. Each circuit has its own liquid header or distribution mechanism, allowing precise control over refrigerant flow to each circuit. This segmentation ensures uniform refrigerant distribution and proper phase distribution within the active second circuit during dehumidification, while maintaining system simplicity through modular design.
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 system effectively dehumidifies air without overcooling, reduces energy usage, and provides uniform refrigerant distribution across the evaporator, enhancing dehumidification capabilities while maintaining energy efficiency and eliminating the need for additional reheat coils.
Implementation Method 1
The evaporator arrangement includes a plurality of refrigerant circuits... Heat transfer fluid is flowed over the evaporator, the heat transfer fluid being in a heat exchange relationship with the evaporator
Implementation Method 2
The plurality of circuits are arranged into a first and second set of circuits... Flow of refrigerant is permitted from the condenser to both the first and second set of refrigerant circuits when the operational mode is cooling
Data Source
AI summary
An HVAC system including a compressor, a condenser and an evaporator arrangement connected in a closed refrigerant loop. The evaporator arrangement includes a plurality of refrigerant circuits. The evaporator arrangement also includes at least one distributor configured to distribute and deliver refrigerant to each circuit of the plurality of circuits. The plurality of circuits are arranged into a first and second set of circuits. The evaporator arrangement also includes a valve configured and disposed to isolate the first set of circuits from refrigerant flow from the condenser and provide flow of refrigerant from the compressor in a dehumidification operation of the HVAC system.