Method and system for optimizing a speed of at least one of a variable speed compressor and a variable speed circulation fan to improve latent capacity
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Solution Overview
Problem
HVAC systems face challenges in optimizing discharge air temperature and compressor speed during dehumidification, leading to inefficiencies in latent capacity and increased energy consumption due to fixed setpoints and limited blower speed control.
Innovation Solution
A variable-speed HVAC system with a controller that adjusts the speed of the compressor and circulation fan based on temperature sensors to lower discharge air temperature from a first setpoint to a second setpoint when the enclosed space temperature falls below a minimum threshold, maintaining a favorable sensible-to-total heat ratio and enhancing dehumidification effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed setpoints for discharge air temperature and compressor speed are used, then the system operation is simple, but the latent capacity is not optimized and energy consumption increases
Solution Approach 1:
The patent implements variable-speed control for both the circulation fan and compressor, allowing the system to dynamically adjust operating parameters based on real-time temperature measurements. The circulation fan speed is modulated to maintain discharge air temperature within a specific range (40-50°F), and the compressor speed is adjusted accordingly to optimize latent capacity and prevent frosting, replacing fixed setpoint operation with adaptive dynamic control.
Solution Approach 2:
The system employs temperature sensors to continuously monitor discharge air temperature and enclosed space temperature, feeding this information back to the controller. The controller uses this feedback to modulate fan and compressor speeds, creating a closed-loop control system that optimizes latent capacity while preventing frosting conditions, thereby resolving the contradiction between simple operation and optimized performance.
2Productivity
If discharge air temperature is lowered to improve dehumidification, then latent capacity increases, but the risk of frost formation increases
Solution Approach 1:
Temperature sensors monitor both the enclosed space temperature and discharge air temperature, providing feedback to the controller. The controller uses this feedback to maintain discharge air temperature within a safe range (40-50°F) that enables effective dehumidification while preventing frost formation on the evaporator coil, thus resolving the contradiction between dehumidification effectiveness and frost risk.
Solution Approach 2:
The system dynamically changes the discharge air temperature parameter based on real-time conditions. By modulating the circulation fan speed and compressor speed, the system adjusts the discharge air temperature to optimize the sensible-to-total heat ratio, enabling effective latent heat removal while maintaining temperatures above the frost point through precise parameter control.
3Power
If compressor speed is increased to meet cooling demand, then cooling capacity increases, but energy consumption increases
Solution Approach 1:
The patent implements variable-speed compressor control that dynamically adjusts compressor speed based on the modulating fan speed and real-time temperature conditions. This allows the compressor to operate at optimal speeds to meet cooling demand without excessive energy consumption, replacing fixed-speed operation with adaptive dynamic control that optimizes the balance between cooling capacity and energy use.
Solution Approach 2:
The system dynamically changes the compressor speed parameter in response to varying cooling demands and discharge air temperature conditions. By modulating the compressor speed alongside the fan speed, the system maintains efficient operation across different load conditions, optimizing the balance between cooling capacity delivery and energy consumption.
4Productivity
If circulation fan speed is increased to improve air circulation, then cooling distribution improves, but discharge air temperature increases reducing dehumidification effectiveness
Solution Approach 1:
The patent implements variable-speed circulation fan control that dynamically adjusts fan speed based on real-time discharge air temperature measurements. The controller modulates fan speed to maintain discharge air temperature within the optimal 40-50°F range, balancing cooling distribution effectiveness with dehumidification performance by preventing temperature from rising too high, thereby resolving the contradiction between these two objectives.
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 increases the latent capacity of the HVAC system, reduces energy consumption by preventing re-evaporation of removed moisture, and extends operating times to minimize on/off cycling, thereby improving dehumidification efficiency and reducing the risk of component damage from frost formation.
Implementation Method 1
A variable-speed compressor is fluidly coupled to the condenser coil and the evaporator coil
Implementation Method 2
an evaporator coil and a metering device fluidly coupled to the evaporator coil
Implementation Method 3
enhancing dehumidification effectiveness
Implementation Method 4
a condenser coil fluidly coupled to the metering device
Implementation Method 5
condenser coil and the evaporator coil
Implementation Method 6
A variable-speed circulation fan for circulating air around the evaporator coil
Data Source
Figure 1
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Figure 3
AI summary
An HVAC system includes an evaporator coil and a metering device. The HVAC system includes a variable-speed circulation fan and a condenser coil fluidly coupled to the metering device. A variable-speed compressor is fluidly coupled to the condenser coil and the evaporator coil. A controller is operatively coupled to the variable-speed compressor and the variable-speed circulation fan. A second temperature sensor is disposed in an enclosed space. The second temperature sensor measures temperature of the enclosed space and transmits the temperature of the enclosed space to the controller. The controller determines if the temperature of the enclosed space is below a minimum threshold. Responsive to a determination that the temperature of the enclosed space is below the minimum threshold, the controller modulates at least one of a speed of the variable-speed compressor and the variable-speed circulation fan to lower a discharge air temperature.