Variable Pump Control Using Dual Temperature Feedback in Heating

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing heating systems with variable delivery pumps experience energy inefficiencies and premature wear due to surge effects and constant temperature adjustments, leading to increased energy consumption and potential clogging in the heat exchanger.

Innovation Solution

A method of controlling the variable delivery pump by comparing the temperatures of both fluids at the heat exchanger outputs with threshold values, adjusting the pump's voltage instruction to optimize delivery based on simultaneous temperature readings, thereby reducing energy losses and preventing surge effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the pump is controlled by temperature of the second fluid only, then the heat transfer can be increased when temperature is low, but the pump generates surge effects and high energy consumption

Engineering Contradiction:
Improveenergy consumptionVSAvoidpump wear
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The control unit uses feedback from both the first temperature sensor (T1) measuring the second fluid temperature and the second temperature sensor (T3) measuring the first fluid temperature to dynamically adjust the pump delivery. This dual-temperature feedback mechanism prevents surge effects by considering the actual thermal state of both circuits, thereby reducing energy consumption and pump wear.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control method changes the operating parameters by comparing both temperatures T1 and T3 against their respective threshold values (Tth1 and Tth3). The pump delivery is adjusted based on the combined thermal state of both circuits, transforming the control from a single-parameter system to a multi-parameter system that optimizes energy efficiency and reliability.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If the pump delivery is increased to meet instantaneous energy demand, then the temperature of the first fluid can be raised, but significant energy losses occur in the primary circuit

Engineering Contradiction:
Improvetemperature of the first fluidVSAvoidenergy losses in primary circuit
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The second temperature sensor (T3) provides feedback on the actual temperature of the first fluid in the primary circuit. The control unit uses this feedback to adjust pump delivery, ensuring that the first fluid temperature is raised only when actually needed, thereby minimizing energy losses in the primary circuit while maintaining adequate heat transfer capability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The pump delivery is made dynamic and adaptive based on real-time temperature measurements from both circuits. Instead of maintaining a fixed high delivery to ensure temperature requirements are met, the system dynamically adjusts delivery to match the actual thermal demands of both the primary and secondary circuits, reducing unnecessary energy consumption.

Inventive Principle:
Principle #15Dynamics

3Temperature

If the pump is activated and stopped repeatedly to meet temperature demands, then the temperature control can be maintained, but premature wear of the pump occurs

Engineering Contradiction:
Improvetemperature controlVSAvoidpump service life
Core Design Contradiction:
TemperatureVSDuration of action of stationary object

Solution Approach 1:

The dual-temperature feedback system allows the control unit to make smoother, more gradual adjustments to pump delivery by considering the thermal state of both circuits. This prevents repeated activation and stopping by providing a more stable control signal that maintains temperature control while extending pump service life through reduced mechanical stress.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control unit anticipates temperature requirements by continuously monitoring both circuit temperatures and adjusting pump delivery proactively. This preliminary action prevents temperature deviations that would require corrective pump activation, thereby reducing the frequency of pump start-stop cycles and extending pump service life.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If the maximum pump delivery is fixed, then the system structure can be simplified, but the system cannot adapt to different actual uses

Engineering Contradiction:
Improveadaptability to different usesVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control unit implements a feedback-based adaptation mechanism that automatically adjusts pump delivery based on real-time temperature measurements from both circuits. This feedback-driven approach enables the system to adapt to different actual uses without requiring complex manual configuration or multiple fixed-delivery pumps, achieving versatility with moderate control complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-adjustment of pump delivery by comparing temperatures T1 and T3 with their respective thresholds and automatically generating appropriate control instructions. This self-service capability allows the system to adapt to different uses autonomously without external intervention, balancing adaptability with controlled system complexity.

Inventive Principle:
Principle #25Self-service

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 reduces energy losses, minimizes clogging, and allows for self-adjusting maximum pump delivery, ensuring efficient and adaptive heat transfer without manual intervention.

Implementation Method 1

a first fluid coming from a primary circuit transmits heat energy to a second fluid coming from a secondary circuit

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a first fluid coming from a primary circuit transmits heat energy to a second fluid coming from a secondary circuit via the heat exchanger

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

said variable delivery pump making it possible to vary the flow rate of the first fluid inside the heat exchanger

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 4

a first temperature sensor S1 provided at the heat exchanger output and measuring a temperature T1 of the second fluid coming from the secondary circuit; a second temperature sensor S3 provided at the heat exchanger output and measuring a temperature T3 of the first fluid coming from the primary circuit

Methodology Applied
Scientific EffectTemperature sensing: Thermocouple

Data Source

PatentEP2587171B1Method of controlling a variable delivery pump fitted to a heating system
Publication Date: 2014.03.19 ALFA LAVAL CORP AB
  • EP2587171B1 patent drawingFigure 1~2

AI summary

Method of controlling a variable delivery pump (2) fitted to a heating system (1) comprising: - a heat exchanger (3) connected to two circuits of fluids (4, 5), said variable delivery pump (2) making it possible to vary the flow-rate of the first fluid inside the heat exchanger (3); - a return loop (6) on the primary circuit (4) allowing the first fluid reaching the input (7) of the heat exchanger (3) to mix with a portion of the first fluid coming from the output (8) of the exchanger (3); - a first temperature sensor S1 measuring a temperature T1 of the second fluid coming from the secondary circuit (5); - a second temperature sensor S3 measuring a temperature T3 of the first fluid coming from a primary circuit (4); - a control unit (9) electrically connected to said first and second temperature sensors S1, S3, said sensors S1, S3 generating electrical signals as functions of the temperatures T1 and T3 and constituting electrical input signals of the control unit (9).