Row Split Coil Configuration for HVAC Part-Load Air Bypass Control
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Solution Overview
Problem
HVAC systems with interlaced or stacked refrigeration coils experience reduced operating efficiency due to air bypass, which leads to incomplete heat transfer and increased humidity, resulting in higher compressor power usage and lower coefficient of performance.
Innovation Solution
Implementing a row split coil system where condenser and evaporator coils are arranged in a nested configuration, allowing air to flow sequentially through active coils during part-load operation, reducing temperature lift and enhancing thermal energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If interlaced or stacked coil configuration is used, then space utilization is improved, but air bypass occurs causing reduced heat transfer efficiency
Solution Approach 1:
The coil assembly is segmented into multiple independent coil rows (first coil row, second coil row, third coil row) arranged in series flow configuration. Each row functions as a separate heat transfer zone, ensuring that air passing through the coil assembly sequentially contacts active portions of each row without bypassing any section, thereby maintaining high heat transfer efficiency while utilizing compact space.
Solution Approach 2:
The coil rows are nested within a common coil assembly housing with air flow passages configured to guide air through each nested row in sequence. This nested arrangement allows multiple coil rows to occupy overlapping spatial volumes while maintaining series flow, achieving high space utilization without creating air bypass paths.
2Use of energy by moving object
If part-load operation with interlaced coils is used, then energy consumption is reduced, but inactive coil portions cause air bypass and increased humidity
Solution Approach 1:
Different coil rows are assigned different operational states (active or inactive) based on local cooling demands. During part-load operation, only the necessary number of coil rows are activated while others remain inactive, allowing the system to match local heat transfer needs with actual load requirements. This prevents air bypass issues because active rows are configured to utilize the entire air flow path.
Solution Approach 2:
The system dynamically adjusts the operational state of individual coil rows based on real-time load conditions. Control mechanisms enable selective activation/deactivation of specific coil rows during part-load operation, optimizing energy consumption while maintaining proper air flow distribution through active rows to prevent humidity increase from air bypass.
3Shape
If stacked coil arrangement is used, then compact design is achieved, but inactive portions reduce operating efficiency
Solution Approach 1:
Multiple coil rows are nested within a compact common housing structure, with each row positioned to utilize the available space efficiently. The nested configuration allows the coil assembly to maintain a compact external dimensions while internally accommodating multiple series-flow rows that all contribute to heat transfer when activated, eliminating the productivity loss associated with inactive portions in traditional stacked arrangements.
Solution Approach 2:
The compact coil assembly is segmented into multiple independent functional rows that can be selectively activated. This segmentation allows the system to maintain a compact overall shape while ensuring that only the necessary portion of the total coil surface area is active during part-load operation, preventing the operating efficiency reduction that would occur if entire stacked coils remained inactive.
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 row split coil system decreases compressor power consumption, increases the coefficient of performance, and improves dehumidification efficiency by ensuring air passes through active coils during part-load operation, thereby enhancing overall HVAC system efficiency.
Implementation Method 1
the refrigerant flowing within the closed circuit is generally formulated to undergo phase changes within the normal operating temperatures and pressures of the HVAC system so that quantities of heat can be exchanged by virtue of the latent heat of vaporization of the refrigerant
Implementation Method 2
the refrigerant flowing within the closed circuit is generally formulated to undergo phase changes within the normal operating temperatures and pressures of the HVAC system so that quantities of heat can be exchanged by virtue of the latent heat of vaporization of the refrigerant
Implementation Method 3
Within the evaporator, condensate from the air passing though the active coil may collect on the active coil and flow downward onto a portion of the inactive coil, which may evaporate into the air and increase a humidity of the air provided to a building
Implementation Method 4
the first condenser and the second condenser are arranged in a first row split configuration, and the second condenser is downstream of the first condenser relative to a first air flow directed across the second condenser and the first condenser
Data Source
AI summary
A multiple-circuit heating and cooling system includes a first refrigeration circuit having a first condenser and a first evaporator and a second refrigeration circuit having a second condenser and a second evaporator. The first condenser and the second condenser are arranged in a first row split configuration, and the second condenser is downstream of the first condenser relative to a first air flow directed across the second condenser and the first condenser. Additionally, the first evaporator and the second evaporator are arranged in a second row split configuration, and the first evaporator is downstream of the second evaporator relative to a second air flow directed across the first evaporator and the second evaporator.