Hydronic Pump Control Using Thermal Differential Instead of Pressure
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Solution Overview
Problem
Existing closed loop thermal energy distribution systems rely on pressure measurements to control water circulation, which is not directly related to the actual heating or cooling load of the building, leading to inefficiencies and difficulties in controlling systems without valves or with unrestricted water flow.
Innovation Solution
A control method that uses the input and output temperature difference and flow rate of water to determine the heating or cooling load, allowing for discrete control of the water circulation system, eliminating the need for pressure sensors and enabling efficient energy use by adjusting pump speed based on actual building loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure measurements are used to control water circulation, then flow control is achieved, but the control is not directly related to actual heating or cooling load
Solution Approach 1:
The patent replaces pressure-based mechanical control systems with a thermal-based control system that directly measures temperature differential and flow rate to determine actual thermal load. This substitution eliminates the information loss inherent in pressure-based systems by directly measuring the thermal parameters that define the building's heating or cooling requirements.
Solution Approach 2:
The patent introduces temperature differential (ΔT) and flow rate measurements as intermediary parameters that directly correlate with thermal load. These intermediaries provide accurate information about the building's actual heating or cooling requirements, serving as a bridge between the water circulation system and the thermal load without the information loss present in direct pressure control.
2Stress or pressure
If fixed speed pump with valving is used, then pressure control is achieved, but system complexity increases and energy efficiency decreases
Solution Approach 1:
The patent extracts the pressure control function from the system by eliminating valves and pressure control mechanisms. Instead of controlling pressure through complex valving systems, the invention directly controls flow rate based on thermal load requirements, removing unnecessary complexity while maintaining effective system control.
Solution Approach 2:
The system performs self-regulation by automatically adjusting flow rate based on measured temperature differential and thermal load requirements. The variable speed pump responds directly to thermal conditions without requiring external pressure control mechanisms or complex valving systems, achieving pressure control through load-responsive flow adjustment.
3Productivity
If variable speed pump with valving is used, then pressure and flow control are achieved, but energy consumption increases
Solution Approach 1:
The patent implements dynamic flow rate adjustment that continuously adapts to changing thermal load conditions. The variable speed pump operates dynamically, increasing or decreasing flow rate in direct response to measured temperature differential and thermal requirements, ensuring optimal energy consumption at all operating conditions rather than maintaining constant high flow rates.
Solution Approach 2:
The system changes the operating parameters of the pump based on actual thermal load conditions. By adjusting pump speed and flow rate as a function of measured temperature differential and thermal requirements, the system optimizes energy consumption while maintaining adequate flow control capability to meet varying building demands.
4Ease of operation
If pressure control is used in systems without valves, then flow control becomes difficult, but system simplicity is maintained
Solution Approach 1:
The patent implements a feedback control system that measures temperature differential and flow rate to determine thermal load, then adjusts pump speed accordingly. This closed-loop feedback provides reliable flow control in valveless systems by continuously monitoring thermal conditions and automatically adjusting flow rates to match actual heating or cooling requirements.
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 allows for precise control of thermal energy distribution, reducing energy consumption, extending pump life, and preventing overheating or overcooling, while adapting to varying building loads and weather conditions, thus enhancing the efficiency and reliability of thermal energy management systems.
Implementation Method 1
A pump circulates water in the system
Implementation Method 2
Heat is absorbed or dissipated to or from the medium to heat or cool loads that are in thermal contact with the closed loop water circulation system
Implementation Method 3
The controller calculates the thermal load on the building based on the measured temperature difference and flow rate
Data Source
AI summary
A system and method for controlling a building system includes a supply temperature sensor upstream of a thermal load, a return temperature sensor downstream of the thermal load, and a controller. The controller is configured to calculate an actual thermal energy difference from the supply and return temperature sensors. The controller is configured to control a flow rate of a pump such that the measured thermal energy difference is equal to a desired thermal energy difference for the system, and the measured thermal energy difference is constant for a time interval. A system and method for controlling a building system includes determining a desired thermal energy difference for a load, measuring a supply and return temperature of the load, and reducing the system flow rate such that a valve controlling the load flow rate is at an at partially open condition when the return temperature of the load is the desired return temperature.