Multi-Orifice Expansion Assembly for Variable-Load HVAC Evaporators
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Solution Overview
Problem
HVAC systems face inefficiencies at variable load conditions due to fixed orifice expansion devices, leading to ineffective refrigerant expansion and distribution in micro-channel heat exchangers, resulting in reduced performance and compressor lifespan.
Innovation Solution
A capacity modulating assembly with multiple expansion devices and flow control valves, including solenoid and check valves, that can be opened or closed to adjust refrigerant flow based on load conditions, ensuring optimal expansion and distribution within the heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed orifice expansion device is used, then the device structure is simple, but the refrigerant expansion effectiveness deteriorates at variable load conditions
Solution Approach 1:
The expansion device is divided into multiple independent orifices (first orifice, second orifice, etc.) that can be selectively opened or closed. Each orifice is equipped with its own flow control valve, allowing the system to segment refrigerant flow paths and activate only the necessary number of orifices based on load conditions, thereby maintaining expansion effectiveness without excessive complexity.
Solution Approach 2:
The expansion device transitions from a fixed orifice configuration to a dynamic configuration where the number of active orifices can be adjusted in real-time. Flow control valves enable dynamic opening and closing of individual orifices based on system load requirements, allowing the expansion device to adapt its capacity and maintain effectiveness across varying operating conditions.
2Reliability
If multiple expansion devices with flow control valves are used, then the refrigerant expansion effectiveness is improved, but the device complexity increases
Solution Approach 1:
The system uses multiple independent orifices with individual flow control valves, allowing selective activation based on load conditions. This segmentation enables the system to achieve variable capacity control without requiring a completely complex redesign, as each orifice-valve pair functions as an independent module.
Solution Approach 2:
Multiple orifices with flow control valves serve dual purposes: they provide capacity modulation for variable load conditions and ensure proper refrigerant distribution across the heat exchanger. The same structural elements that increase complexity also deliver multiple functional benefits including expansion control, flow distribution, and capacity adjustment.
3Use of energy by moving object
If the number of active orifices is reduced at partial load, then the energy efficiency is improved, but the device complexity increases
Solution Approach 1:
The system dynamically adjusts the number of active orifices based on load conditions, closing unnecessary orifices at partial load to reduce energy consumption. This dynamic adjustment capability allows the system to optimize energy efficiency by matching refrigerant flow to actual heating or cooling demands, with each orifice equipped with a flow control valve for selective activation.
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 solution maintains effective refrigerant expansion and distribution across varying load conditions, enhancing the performance and longevity of HVAC systems by ensuring proper refrigerant flow and temperature management.
Implementation Method 1
The flow control device can be closed to prevent refrigerant from flowing into the connected expansion device
Implementation Method 2
The capacity modulating assembly can be configured to expand liquid refrigerant to, for example, a two-phase refrigerant mixture in a HVAC system
Implementation Method 3
Outer surfaces of the micro-channel tubes and the fins may help heat exchange between the first fluid (such as refrigerant) in the micro-channel tubes and a second fluid (such as air) flowing across the outer surfaces of the micro-channel tubes
Data Source
AI summary
Methods, systems and apparatuses are directed to a capacity modulating assembly configured to distribute two-phase refrigerant mixture to an evaporator of a HVAC system, such as a micro-channel heat exchanger (MCHEX) evaporator. The capacity modulating assembly may include a plurality of expansion devices. During capacity modulation, at least one of the plurality of expansion devices can be closed so that a refrigerant flow rate through the remaining expansion devices can be maintained. The capacity modulating assembly can include a refrigerant outflow port, which may help direct refrigerant out of the heat exchanger. The capacity modulating assembly can be connected with the MCHEX. The plurality of expansion devices can be configured to extend inside a header of the MCHEX to help distribute refrigerant to the micro-channel tubes of the MCHEX.