Away-Mode HVAC Humidity Control for Unoccupied Spaces
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Solution Overview
Problem
In unoccupied spaces, especially in hot and humid climates, there is a challenge in maintaining indoor air quality by preventing mold and mildew buildup while conserving energy, as existing HVAC systems often require complex configuration of thermostats and humidistsats, and may lead to either insufficient dehumidification or excessive energy consumption due to incorrect settings.
Innovation Solution
A controller with an 'away mode' that operates HVAC system components to maintain humidity and temperature levels, including overcooling if necessary, to prevent mold and mildew growth, even without a humidity sensor, by using pre-programmed settings and offset temperatures to account for temperature differences within the space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air conditioner is used to lower the inside temperature to reduce humidity levels, then humidity control is improved, but energy consumption increases and may cause moisture buildup if the dewpoint temperature is greater than the room temperature
Solution Approach 1:
The system changes the control parameter from temperature setpoint to dewpoint-based control. By monitoring the dewpoint temperature and comparing it with the room temperature, the system determines the appropriate cooling strategy. This parameter change allows the system to achieve effective dehumidification without unnecessary energy consumption by avoiding overcooling when the dewpoint is already below the room temperature.
Solution Approach 2:
The system implements feedback control by continuously monitoring temperature and humidity levels, calculating the dewpoint temperature, and adjusting the air conditioner operation accordingly. The feedback mechanism ensures that cooling is applied only when necessary (when dewpoint exceeds room temperature) and stops when the target humidity level is achieved, preventing both insufficient dehumidification and excessive energy consumption.
2Reliability
If the thermostat and humidistat are configured with correct settings before leaving, then dehumidification control is improved, but the complexity of configuration increases and users often set them incorrectly
Solution Approach 1:
The system performs self-configuration by automatically calculating the appropriate temperature setpoint based on the desired dewpoint temperature and the current room temperature. Instead of requiring users to manually configure both thermostat and humidistat settings, the system autonomously determines the correct parameters, eliminating configuration complexity while ensuring reliable dehumidification control.
Solution Approach 2:
The system introduces an intermediary calculation layer between the user's dehumidification goal and the actual controller settings. By computing the required temperature setpoint as an intermediate value based on dewpoint and current temperature relationships, the system translates the user's intent into precise controller parameters without requiring the user to understand or configure multiple settings.
3Reliability
If the air conditioner runs continuously to maintain low humidity, then humidity control is improved, but the temperature drops below the dewpoint causing moisture buildup on walls
Solution Approach 1:
The system changes the control approach by using dewpoint temperature as the primary control parameter rather than relying solely on temperature setpoint. By calculating and monitoring the dewpoint, the system can determine when cooling should be applied and when it should stop, preventing the temperature from dropping below the dewpoint and causing condensation on walls while still maintaining adequate humidity control.
Solution Approach 2:
The system implements feedback control that continuously monitors both temperature and humidity levels, calculates the dewpoint, and adjusts the air conditioner operation to maintain the temperature above the dewpoint. This feedback mechanism prevents moisture buildup on walls by stopping cooling before the temperature drops to the dewpoint, while still achieving the desired humidity control through controlled dehumidification cycles.
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
Effectively prevents mold and mildew growth while conserving energy by automatically adjusting HVAC operations to maintain optimal humidity levels, even in the absence of a humidity sensor, ensuring indoor air quality and reducing energy bills.
Implementation Method 1
When operated as a dehumidifier, air flowing past the air-conditioning coils results in condensation on the coils, which removes water from the air and reduces the humidity levels within the space.
Implementation Method 2
the controller can be configured to operate the air conditioner to overcool the interior space at the indoor dewpoint temperature plus the offset temperature
Data Source
AI summary
Methods of providing dehumidification control in unoccupied spaces are disclosed. An illustrative method can include the steps of providing a controller having an away mode of operation adapted to provide dehumidification within the interior space of a building or room, providing one or more system components adapted to control the humidity and/or temperature within the interior space, initiating the away mode of operation within the controller, and operating the one or more system components for at least one cycle to reduce the humidity within the interior space.