HVAC Virtual Sensor Method to Reduce Flow Measurement Complexity

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Solution Overview

Problem

Existing HVAC installations face challenges in accurately measuring fluid flow rates and enthalpy differences due to the use of multiple sensors, which increase energy demands, impair flow characteristics, and incur high maintenance and operational costs, especially in large ducts with boundary curve effects.

Innovation Solution

A method and system that reduces the number of sensors by using virtualized sensors, where non-calibrated auxiliary sensors are calibrated through mathematical and empirical relationships with measured variables, allowing for reduced sensor installation and maintenance costs while maintaining fluid flow characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple flow sensors are placed within ducts to measure flow rates accurately, then measurement precision is improved, but device complexity and energy consumption increase

Engineering Contradiction:
Improveflow rate measurement accuracyVSAvoidsensor arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the measurement function from physical sensors placed within the duct and relocates it to a virtual sensor implemented through software algorithms. The virtual sensor calculates flow rates by processing data from existing sensors (temperature, pressure, humidity) without requiring additional physical measurement devices in the airflow path, thereby eliminating the complexity of sensor arrangements while maintaining measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a virtual copy of the flow measurement function through software simulation rather than using physical sensors. The virtual sensor replicates the measurement capability by computing flow rates from thermodynamic relationships and existing sensor data, providing an accurate representation of actual flow conditions without the physical presence of measurement devices in the duct.

Inventive Principle:
Principle #26Copying

2Measurement precision

If multiple sensors are installed in large ducts to overcome boundary curve effects, then measurement precision is improved, but manufacturing cost and maintenance cost increase

Engineering Contradiction:
Improveflow rate measurement accuracyVSAvoidinstallation cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent removes the requirement for multiple physical sensors in large ducts by extracting the measurement function to a virtual sensor. The system uses existing sensors combined with thermodynamic calculations to determine flow rates, eliminating the need for expensive sensor arrays and reducing both installation and maintenance costs while maintaining accuracy in large duct configurations.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical sensor array system with a computational approach. Instead of using multiple physical sensors arranged in specific patterns within the duct, the system uses software algorithms that process data from existing sensors to calculate flow rates, substituting a mechanical measurement system with an information-processing system that is cheaper to install and maintain.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If rods with sensors are placed within fluid flow, then measurement capability is improved, but flow resistance increases and energy consumption rises

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidenergy consumption for fluid movement
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the measurement function from physical rods with sensors that obstruct flow and relocates it to a virtual sensor system. By calculating flow rates from existing sensor data and thermodynamic relationships, the system maintains measurement capability without introducing physical obstructions that would increase flow resistance and energy consumption for fluid movement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a computational intermediary (virtual sensor algorithm) that mediates between existing sensors and the measurement objective. Instead of placing physical rods in the flow path, the system uses software processing of temperature, pressure, and humidity data to derive flow rate information, eliminating the need for flow-obstructing measurement devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If sensors and rods are placed in ducts, then measurement function is provided, but fouling occurs and measurement accuracy decreases

Engineering Contradiction:
Improvemeasurement functionVSAvoidmeasurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent extracts the measurement function from physical sensors and rods that are susceptible to fouling and relocates it to a virtual sensor. By calculating flow rates from existing sensor data through thermodynamic relationships, the system maintains measurement capability without the physical components that would accumulate dust and dirt, thereby preventing the degradation of measurement accuracy over time.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3420283B1Method, arrangement, and computer program product for operating an HVAC installation
Publication Date: 2025.08.27 BELIMO HOLDING AG
  • EP3420283B1 patent drawingFigure 1
  • EP3420283B1 patent drawingFigure 2
  • EP3420283B1 patent drawingFigure 3

AI summary

A method, system (100), and a computer program product comprising a non-transient computer-readable medium (190) having stored thereon computer program code configured to control one or more processors (180) of a computer (170) for operating an HVAC installation (200, 300), wherein a set of enthalpies (Η1,i, H2,i, H1,o, H2,o) and flow rates (ϕ1, ϕ2) as variables of the HVAC installation (200, 300) is monitored and used for controlling the operation of said HVAC installation (200, 300), comprising the steps of: (a) dividing said set of enthalpies (Η1,i, H2,i, H1,o, H2,o) and flow rates (ϕ1, ϕ2) into a first and second subset; (b) measuring each variable of said first subset with a related sensor (110, 120) arranged in said HVAC installation (200, 300); and (c) determining the variables of said second subset from the measured variables of said first subset by using a mathematical and/or empirical relationship between the variables of said first and second subset.