Ventilation Coil Control for Humidity and Condensation Balance
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Solution Overview
Problem
Conventional air-conditioning and ventilation systems fail to maintain indoor humidity within a comfortable range when dehumidifying, leading to excessive cooling, increased energy consumption, and user discomfort, as they rely solely on outdoor temperature for controlling the air-conditioning coil's cooling capacity without considering outdoor humidity.
Innovation Solution
An air-conditioning and ventilation apparatus that includes a control unit using outdoor-air temperature and humidity sensors to adjust the air-conditioning coil's cooling capacity in multiple stages, ensuring the absolute humidity of supplied air remains equal to or lower than the indoor target, based on reference data and real-time outdoor conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air-conditioning coil operates at 100% cooling capacity for dehumidification irrespective of outdoor humidity, then the dehumidifying function is ensured, but the blown-out temperature drops excessively causing dew condensation on the blow-out grill
Solution Approach 1:
The invention changes the control parameter from fixed 100% cooling capacity to variable cooling capacity based on outdoor humidity conditions. When outdoor humidity is low, the cooling capacity is reduced to prevent excessive temperature drop and dew condensation, while maintaining sufficient dehumidification effectiveness.
Solution Approach 2:
The invention makes the cooling capacity dynamic rather than static. The air-conditioning coil's cooling capacity automatically adjusts according to outdoor humidity levels, transitioning between different operating states (high capacity when outdoor humidity is high, low capacity when outdoor humidity is low) to optimize both dehumidification and prevent harmful condensation.
2Reliability
If the air-conditioning coil operates at high cooling capacity to ensure dehumidification, then indoor humidity is controlled, but energy consumption increases
Solution Approach 1:
The invention optimizes the cooling capacity parameter based on outdoor humidity conditions. By reducing cooling capacity when outdoor humidity is already low, the system maintains effective humidity control while significantly reducing energy consumption during such periods.
3Reliability
If the air-conditioning coil operates at full cooling capacity, then dehumidification is effective, but the blown-out temperature becomes excessively low causing user discomfort
Solution Approach 1:
The invention dynamically adjusts cooling capacity based on outdoor humidity to maintain optimal supply air temperature. When outdoor humidity is low, reduced cooling capacity prevents excessive temperature drop, ensuring supply air remains comfortable for users while still achieving effective dehumidification.
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 effectively maintains indoor humidity within comfortable limits, reduces energy consumption by adjusting cooling capacity according to dehumidification needs, and prevents excessive cooling, thereby enhancing user comfort and energy efficiency.
Implementation Method 1
a heat exchanger that is provided between the supply air trunk and the exhaust air trunk to perform heat exchange between the supply air and the exhaust air
Implementation Method 2
an air-conditioning coil that is provided on a downstream side of the heat exchanger in the supply air trunk and that changes cooling capacity with respect to the outdoor air after heat exchange has been performed
Data Source
AI summary
An air-conditioning and ventilation apparatus includes an air-conditioning coil that is installed on a downstream side of a heat exchanger in a supply air trunk and changes cooling capacity with respect to heat-exchanged outdoor air in multiple stages; an outdoor-air temperature and humidity sensor that detects temperature and relative humidity of the outdoor air; and a control unit that stores therein reference data in which the cooling capacity is set for each combination of temperature and relative humidity of the outdoor air such that absolute humidity of supply air becomes equal to or lower than indoor target absolute humidity on the basis of a dehumidification load corresponding to an absolute humidity difference between indoors and outdoors, and determines a cooling capacity value of the air-conditioning coil on the basis of detection results during a cooling operation by the outdoor-air temperature and humidity sensor and the reference data.