HVAC Return Temperature Control Based on Dynamic Flow Threshold
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Solution Overview
Problem
HVAC systems face inefficiencies due to excessive heat and water flow, leading to unwanted energy usage and low delta T, which existing methods fail to optimize effectively.
Innovation Solution
A method and control system that adjust fluid flow through a thermal energy exchange system based on a threshold temperature dependent on the current flow, independent of inlet temperature measurements, to optimize energy usage and prevent flow from exceeding design limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the flow of fluid through the coil is increased to meet heating or cooling demand, then the heating or cooling capacity is improved, but the return temperature becomes too low causing excessive energy usage at the generation and distribution sides
Solution Approach 1:
The patent applies dynamics by making the flow control adaptive rather than static. The controller dynamically adjusts the flow of fluid through the coil based on real-time comparison between the actual return temperature and a dynamically calculated threshold return temperature, allowing the system to optimize energy efficiency while meeting varying heating or cooling demands throughout operation
Solution Approach 2:
The patent implements feedback control by continuously measuring the return temperature, comparing it against a threshold value, and adjusting the flow accordingly. This closed-loop feedback mechanism ensures the system maintains optimal operating conditions by correcting deviations from the threshold return temperature, thereby preventing excessive energy usage while preserving heating or cooling capacity
2Loss of energy
If the flow of fluid through the coil is decreased to reduce energy usage, then the energy efficiency is improved, but the heating or cooling capacity becomes insufficient
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the threshold return temperature parameter based on the ratio of actual flow to design flow. As flow conditions change, the threshold temperature parameter is recalculated and applied, allowing the system to maintain optimal energy efficiency across different operating conditions while ensuring sufficient heating or cooling capacity is delivered
3Ease of operation
If a fixed threshold return temperature is used for flow control, then the control simplicity is maintained, but the system cannot adapt to varying flow conditions and design requirements
Solution Approach 1:
The patent transforms the static threshold return temperature into a dynamic parameter that automatically adapts to varying flow conditions. The threshold is calculated based on the ratio of actual flow to design flow, enabling the system to maintain optimal performance across different operating conditions without requiring complex manual adjustment or sacrificing control simplicity
Solution Approach 2:
The system applies self-service by automatically calculating and adjusting its own threshold return temperature based on measured flow conditions and design parameters. This self-adjusting mechanism eliminates the need for external intervention or complex control algorithms, allowing the system to adapt to varying conditions autonomously while maintaining operational simplicity
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 stabilizes return temperatures, reduces energy consumption, and allows for additional operational points, enhancing comfort and efficiency by dynamically controlling fluid flow based on current flow conditions.
Implementation Method 1
A flow of a fluid through a thermal energy exchange system is generated. The flow of the fluid through the thermal energy exchange system results in an exchange of thermal energy between a primary side of the thermal energy exchange system and a secondary side of the thermal energy exchange system.
Data Source
Figure 1~2
AI summary
It is an object of the present disclosure to optimize energy usage of an HVAC system. This object is achieved by the solutions presented in the independent claims. Operation of an HVAC system is optimized by (a) generating a flow (31) of a fluid through a thermal energy exchange system (7) of the HVAC system (3) resulting in an exchange of thermal energy between a primary side of the thermal energy exchange system (7) and a secondary side of the thermal energy exchange system (7); (b) determining a return temperature of fluid having passed through thermal energy exchange system (7); (c) determining a current flow of the fluid through the thermal energy exchange system (7); (d) controlling the flow of the fluid based on a comparison of the determined return temperature with a threshold temperature (TrtLim), wherein the threshold temperature is dependent on the current flow.