Modulated heating/cooling system control
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Solution Overview
Problem
Traditional hydronic heating/cooling systems face challenges in achieving multiple heating zones economically due to the need for a special modulating heat source and the inability to modulate down to low flow temperatures, leading to inefficient 'on/off' control during mild weather conditions.
Innovation Solution
A controller system with a mixing valve and actuator that adjusts the water flow ratio between a boiler inlet and a return pipe inlet to achieve a targeted outlet temperature, allowing for enhanced modulation control and supporting multiple zones with a single heat generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional direct boiler modulation is used, then a single heating zone can be controlled, but multiple heating zones become economically impracticable
Solution Approach 1:
The system divides the heating control into multiple independent mixing valves, each serving a specific zone. Each mixing valve independently blends hot water from the boiler with return water to achieve zone-specific temperature requirements, enabling multiple zones without requiring multiple boilers or complex centralized control
Solution Approach 2:
Mixing valves act as intermediary devices between the single boiler output and multiple zone requirements. The mixing valve blends hot boiler water with cooler return water to create intermediate temperature levels, allowing the system to serve multiple zones with different temperature needs from a single heat source
2Temperature
If traditional boiler modulation is used, then standard heating temperatures can be achieved, but low flow temperatures during mild weather cannot be achieved
Solution Approach 1:
The mixing valve serves as an intermediary that blends hot boiler water with cooler return water to achieve low flow temperatures that the boiler alone cannot produce. This allows the system to deliver low-temperature heating during mild weather conditions while the boiler operates at its optimal temperature range
Solution Approach 2:
The system changes the temperature parameter of the water delivered to zones by adjusting the mixing ratio in the mixing valve. By varying the proportion of hot boiler water and cool return water, the system can deliver a wide range of flow temperatures from the same boiler output
3Ease of operation
If traditional on/off control is used, then simple control is achieved, but energy efficiency deteriorates during low-load situations
Solution Approach 1:
The mixing valve provides dynamic modulation capability by continuously adjusting the mixing ratio of hot and return water. This allows the system to respond smoothly to changing load conditions rather than switching on/off, maintaining energy efficiency during partial-load operations while keeping control relatively simple
Solution Approach 2:
The system uses feedback from zone temperature sensors to automatically adjust the mixing valve position, maintaining the desired temperature without manual intervention. This closed-loop control achieves energy efficiency through continuous optimization while keeping the user interface simple
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
Enables efficient modulation of heating/cooling outputs across multiple zones without the need for specialized boilers, allowing for low flow temperatures and reducing energy consumption by stabilizing temperatures within desired ranges.
Implementation Method 1
a first mixing valve, the first mixing valve including a first A inlet, a first B inlet and a first A/B outlet... to determine an updated inlet ratio from the first targeted outlet temperature and an updated measured outlet temperature... indicative of an updated water flow ratio
Implementation Method 2
a first actuator connected to the first mixing valve, the first actuator configured to control first water flows through the first A inlet and the first B inlet based on the first inlet ratio
Implementation Method 3
the first hydronic emitter affects environmental conditions of the first controlled entity... power transfer from one or more of the hydronic emitters to affect one or more environmental entities
Data Source
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AI summary
A heating/cooling system modulates the temperature of water flowing through a hydronic emitter by mixing water flows through a mixing valve. The mixing valve has an inlet connect to a water flow pipe, an inlet connected to a water return pipe, and an outlet connected to the hydronic emitter. Water flows through the inlets are configured to obtain a desired mixed water flow at a targeted temperature through the outlet. A controller receives temperature information from a thermometer and then determines the targeted temperature of the outlet. The controller then determines an inlet ratio and configures the mixing valve based on the ratio. The heating/cooling system may support one or more heating/cooling zones and may operate either in a heating or a cooling mode.