Terminal Unit Latent Cooling via Moisture Threshold Control
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Solution Overview
Problem
Current HVAC control schemes do not effectively utilize the terminal unit's cooling capacity, leading to slower cooling and oversizing of equipment, and fail to leverage latent cooling capabilities, resulting in inefficient humidity regulation.
Innovation Solution
A terminal unit with sensors to measure moisture accumulation and ambient air properties, a controller to adjust coolant properties based on set points and moisture thresholds, allowing for both sensible and latent cooling, and preventing excess moisture accumulation by controlling the latent cooling rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the terminal unit provides latent cooling to improve humidity control, then humidity regulation is improved, but moisture accumulation increases requiring drainage systems
Solution Approach 1:
The patent converts the harmful effect of moisture accumulation into a beneficial feature by allowing the terminal unit to accumulate moisture up to a threshold level and then using this stored moisture for evaporative cooling. Instead of requiring a drainage system to remove condensation, the system retains the condensation and utilizes it as a cooling resource, eliminating the need for complex drainage infrastructure while improving humidity control.
Solution Approach 2:
The patent changes the operational parameters of the terminal unit by dynamically adjusting the coolant temperature and flow rate based on the accumulated moisture level. When moisture accumulation reaches the threshold, the system modifies its cooling operation to prevent further accumulation, thereby eliminating the need for drainage systems while maintaining effective humidity control through parameter optimization.
2Speed
If the terminal unit operates at full cooling capacity, then cooling speed is improved, but equipment size must be oversized to handle peak loads
Solution Approach 1:
The patent implements preliminary action by accumulating moisture during periods when cooling demand is low or ambient conditions are favorable. This pre-accumulated moisture is then utilized during peak cooling demands to provide evaporative cooling, allowing the equipment to operate at reduced capacity during high-demand periods while maintaining fast cooling response.
Solution Approach 2:
The system dynamically changes operational parameters including coolant temperature, flow rate, and fan speed based on real-time conditions and accumulated moisture levels. This enables the terminal unit to deliver high cooling capacity when needed without requiring the equipment to be oversized for peak loads, as the accumulated moisture provides supplemental cooling capacity on demand.
3Productivity
If the terminal unit uses conventional control schemes, then system simplicity is maintained, but cooling efficiency is reduced
Solution Approach 1:
The patent implements feedback control by continuously monitoring moisture accumulation levels, ambient temperature, humidity, and cooling demand. This feedback information is used to dynamically adjust the coolant parameters and cooling operation, optimizing cooling efficiency while preventing excessive moisture accumulation. The feedback mechanism enables the system to adapt to changing conditions and maximize cooling performance.
Solution Approach 2:
The control system transitions from static conventional control to dynamic control that continuously adjusts operational parameters based on real-time conditions. The system dynamically modifies coolant temperature, flow rate, and other parameters in response to changing ambient conditions, moisture accumulation levels, and cooling demands, thereby significantly improving cooling efficiency compared to fixed-parameter conventional systems.
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
Enhances cooling efficiency by allowing latent cooling when moisture is below a threshold, reducing equipment capacity needs, and maintaining comfortable humidity levels without requiring a drainage system, leading to cost savings and improved comfort.
Implementation Method 1
a coil; an actuator operably connected to the coil for regulating a first property of coolant entering the coil
Implementation Method 2
determine an amount of moisture accumulation in the terminal unit based at least in part on the second sensor measurement
Data Source
AI summary
A terminal unit is provided for cooling a conditioned space. The terminal unit is provided conditioned air and augments cooling with a local heat exchanger. The terminal unit controls the flow of coolant through the heat exchanger. Latent cooling provided by the conditioned air is augmented by allowing moisture accumulation on the heat exchanger. The terminal unit lacks a drainage system so deleterious moisture accumulation (e.g., dripping) is avoided by monitoring moisture accumulation and controlling the terminal unit accordingly. If the moisture accumulation is below a threshold, the terminal unit is permitted to provide latent cooling locally. If the moisture accumulation is above a threshold, the terminal unit prevents further local latent cooling. Some sensor configurations allow for calculation of air flow rates, the latent cooling rate, and moisture accumulation. This information is used to achieve the desired room conditions more rapidly and precisely.