HVAC Blower Capacity Control for Dehumidification Without Overcooling
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Solution Overview
Problem
HVAC systems often overcool enclosed spaces during dehumidification, failing to effectively manage both humidity and temperature simultaneously, leading to inefficient operation and increased energy consumption.
Innovation Solution
An HVAC controller that processes both latent and sensible cooling demands simultaneously, directing a dehumidification function based on the operating capacity of the indoor air blower system, while adjusting the operation of compressors and outdoor fans to maximize latent cooling and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dehumidification is achieved by moving air over evaporation coils during mechanical cooling, then humidity is removed, but the enclosed space is overcooled creating a temperature problem
Solution Approach 1:
The system dynamically adjusts blower capacity based on the ratio of latent to sensible cooling demand. When latent demand is high relative to sensible demand, the blower operates at reduced capacity to prevent overcooling while maintaining effective dehumidification. This dynamic adjustment resolves the contradiction by adapting airflow to the specific cooling requirements.
Solution Approach 2:
The system changes the operating parameters of the blower (capacity/speed) based on the type and magnitude of cooling demand. By modifying the blower capacity parameter in response to latent vs. sensible cooling ratios, the system achieves dehumidification without excessive temperature reduction, resolving the contradiction between humidity removal and temperature control.
2Reliability
If the HVAC system processes latent and sensible cooling demands separately, then each function can be optimized, but the system operation becomes inefficient and energy consumption increases
Solution Approach 1:
The system merges the processing of latent and sensible cooling demands into a unified control strategy. The controller simultaneously considers both types of cooling demand and determines blower capacity based on their ratio, rather than treating them as separate functions. This integration improves overall system efficiency and reduces energy consumption while maintaining reliable dehumidification and cooling performance.
Solution Approach 2:
The HVAC system is designed to handle multiple cooling functions (latent and sensible) through a single integrated control mechanism. The blower system serves dual purposes: it provides airflow for both dehumidification and cooling, with its capacity dynamically adjusted based on the combined requirements. This multi-functionality eliminates the need for separate optimization processes and reduces energy waste.
3Temperature
If the blower operates at high capacity to meet sensible cooling demand, then cooling is effective, but dehumidification efficiency decreases when latent cooling demand is present
Solution Approach 1:
The blower capacity is dynamically adjusted based on the ratio of latent to sensible cooling demand. When latent cooling demand is high, the blower operates at reduced capacity to maximize dehumidification efficiency. When sensible cooling demand dominates, the blower operates at higher capacity. This dynamic adjustment ensures optimal performance for the dominant cooling requirement at any given time.
Solution Approach 2:
The system changes the blower capacity parameter in response to the type of cooling demand. By monitoring the ratio of latent to sensible cooling demand, the system adjusts the blower operating parameter to match the primary cooling requirement, thereby maintaining high effectiveness for the dominant function while preserving capability for the secondary function.
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 enhances dehumidification efficiency, avoids unnecessary cooling element operation, and optimizes energy use by matching airflow and compressor capacity with cooling demands, thereby improving humidity control and reducing energy consumption.
Implementation Method 1
an indoor air blower system configured to move air across the evaporator coil
Implementation Method 2
a refrigeration system having at least one compressor, a corresponding evaporator coil and a corresponding condenser coil
Implementation Method 3
an outdoor fan system configured to move air across the condenser coil
Implementation Method 4
moving air over the evaporation coils during mechanical cooling
Data Source
AI summary
An HVAC controller, a method of operating a HVAC unit and a HVAC system are disclosed herein. In one embodiment, the HVAC controller includes: (1) an interface configured to receive both a latent cooling demand and a sensible cooling demand and (2) a processor configured to direct both a dehumidification function and a cooling function when simultaneously processing both the latent cooling demand and the sensible cooling demand, the dehumidification function based on an operating capacity of an indoor air blower system.