Method and apparatus for reheat dehumidification with variable air volume
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Solution Overview
Problem
HVAC systems face challenges in efficiently dehumidifying enclosed spaces without over-cooling, leading to occupant discomfort and increased energy consumption, as existing methods either result in over-cooling or require extended operation times.
Innovation Solution
A variable-speed circulation fan system with a temperature sensor and controller that adjusts fan speed based on evaporator coil surface temperature to enhance latent capacity, allowing for effective dehumidification without altering air temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the circulation fan operates at high speed to enhance cooling capacity, then the cooling effect is improved, but the latent capacity for dehumidification deteriorates
Solution Approach 1:
The circulation fan operates at variable speeds rather than a fixed high speed. The controller dynamically adjusts the fan speed based on real-time evaporator coil surface temperature measurements, enabling the system to optimize between cooling capacity and latent capacity for effective dehumidification without over-cooling
Solution Approach 2:
A temperature sensor continuously monitors the evaporator coil surface temperature and provides feedback to the controller. The controller uses this feedback to adjust the circulation fan speed, creating a closed-loop control system that maintains optimal operating conditions for both cooling and dehumidification
2Reliability
If the HVAC system operates for extended periods to achieve dehumidification, then the dehumidification effectiveness is improved, but the energy consumption increases
Solution Approach 1:
The controller continuously monitors evaporator coil surface temperature and adjusts the circulation fan speed in real-time, enabling the system to achieve effective dehumidification more quickly by optimizing latent capacity, thereby reducing overall operation time and energy consumption
Solution Approach 2:
The system changes the operational parameters by modulating the circulation fan speed based on evaporator coil temperature. This dynamic parameter adjustment allows the system to operate at optimal points for dehumidification, reducing the time required to achieve humidity control goals and lowering energy consumption
3Reliability
If the evaporator coil surface temperature is lowered to enhance dehumidification, then the latent capacity is improved, but the risk of over-cooling and occupant discomfort increases
Solution Approach 1:
The temperature sensor provides continuous feedback on the evaporator coil surface temperature to the controller. This feedback mechanism allows the controller to adjust the circulation fan speed to maintain the coil temperature at optimal levels for dehumidification while preventing excessive cooling that would cause occupant discomfort
Solution Approach 2:
The system dynamically adjusts the circulation fan speed based on real-time evaporator coil temperature conditions. This dynamic control enables the system to optimize latent capacity for dehumidification while maintaining coil temperatures that prevent over-cooling of the enclosed space
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 solution increases the latent capacity of the HVAC system, enabling effective dehumidification without over-cooling, thus improving occupant comfort and reducing energy consumption by optimizing fan speed in response to environmental conditions.
Implementation Method 1
a variable-speed circulation fan for circulating air around the evaporator coil
Implementation Method 2
A temperature sensor is thermally exposed to the distribution line
Implementation Method 3
an evaporator coil and a metering device fluidly coupled to the evaporator coil
Data Source
AI summary
The HVAC system includes an evaporator coil and a metering device fluidly coupled to the evaporator coil via a distribution line. The HVAC system includes a variable-speed circulation fan for circulating air around the evaporator coil. A temperature sensor is thermally exposed to the distribution line. At least one controller is operatively coupled to the temperature sensor and to the variable-speed circulation fan. The at least one controller adjusts a speed of the variable-speed circulation fan to increase latent capacity of the HVAC system responsive to a determination that a temperature of fluid in the distribution line exceeds an optimal distribution line temperature.