Underfloor Heating Loop Control With Staggered PWM Duty Cycles
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Solution Overview
Problem
Existing under floor heating systems face complexity in control due to interdependence of supply loops, requiring intricate algorithms and sensors, and suffer from inefficient balancing, leading to performance issues and high installation costs.
Innovation Solution
Implementing a control method that uses on/off water flow control with pulse width modulation, where the percentage of the duty cycle is adjusted to minimize temperature gradients and interference between loops, allowing for automatic balancing and reduced hardware needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear control algorithms are used to adjust water flow in supply loops, then temperature control in specific rooms is optimized, but the control system becomes very complicated due to interdependence between loops
Solution Approach 1:
The patent divides the heating system into independent supply loops, each controlled separately. By segmenting the control of each loop and using on/off control with duty cycle adjustment rather than continuous linear control, the system achieves temperature control without requiring complex interdependent algorithms across multiple loops
Solution Approach 2:
The patent implements periodic on/off control action in each supply loop by adjusting the duty cycle. Instead of using complex continuous linear control algorithms, the system applies periodic heating cycles where the actuator switches on and off, achieving temperature regulation through pulse width modulation rather than complex continuous adjustment
2Reliability
If balancing is carried out during installation to equalize pressure drops in supply loops, then system performance is improved, but installation time and costs increase
Solution Approach 1:
The patent enables the heating system to automatically balance itself during operation through the controller's duty cycle adjustment algorithms. Rather than requiring manual balancing during installation, the system self-regulates water flow distribution based on actual thermal performance and loop characteristics, eliminating time-consuming manual balancing procedures
Solution Approach 2:
The patent implements dynamic balancing where the controller continuously adjusts duty cycles based on real-time temperature feedback and loop performance. This dynamic adaptation replaces static manual balancing, allowing the system to automatically optimize water flow distribution as installation progresses and conditions change
3Device complexity
If on/off control with duty cycle adjustment is used, then control algorithm complexity is reduced, but temperature gradients in the supply loop may increase
Solution Approach 1:
The patent applies different duty cycle percentages to different supply loops based on their specific characteristics (length, thermal mass, heat demand). By tailoring the on/off control parameters locally to each loop's needs rather than using uniform control, the system achieves even floor temperatures without requiring complex continuous control algorithms
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 simplifies control algorithms, reduces installation time and costs, and enhances system performance by dynamically adjusting energy distribution based on loop length and thermal response, ensuring even floor temperatures without the need for interlaced loops or additional mixers.
Implementation Method 1
The liquid may comprise water or any other suitable liquid medium... supplying liquid or the supply loop... minimal temperature gradient
Data Source
AI summary
Controlling under surface heating/cooling by supplying liquid to at least two supply loops in an under surface heating/cooling system, and controlling the flow of the liquid on and off such that during the duty cycle the flow is high and between the duty cycles the flow is off. Room temperature is controlled by controlling the percentage of the duty cycles, which percentage is determined on the basis of the heating demand of the rooms. Different loops are con¬ trolled such that at least in two different loops the duty cycles start at different moments.