Compressor Exhaust Heat Recovery Path Control for Water Temperature

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Solution Overview

Problem

Existing exhaust heat recovery systems do not effectively utilize thermal energy from all gas compressors and lack a comprehensive connection to exhaust heat recovery devices, leading to inefficiencies in energy use.

Innovation Solution

An exhaust heat recovery system with a controller that connects all gas compressors to a heat recovery device, allowing selective use of an exhaust heat recovery path based on temperature comparisons and operational states, prioritizing efficient heat recovery and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If all gas compressors are connected to the exhaust heat recovery device, then thermal energy recovery efficiency is improved, but system complexity increases

Engineering Contradiction:
Improvethermal energy recovery efficiencyVSAvoidsystem complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges all gas compressors into a unified exhaust heat recovery system, connecting every compressor to the heat recovery device through a common heat exchange mechanism. This integration ensures that thermal energy from all compressors is collectively recovered, maximizing energy efficiency while managing system complexity through standardized connection protocols

Inventive Principle:
Principle #5Merging (Combining)

2Use of energy by moving object

If the controller instructs gas compressors to use the exhaust heat recovery path based on temperature comparison, then energy utilization is improved, but control complexity increases

Engineering Contradiction:
Improveenergy utilizationVSAvoidcontrol complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The controller implements a feedback mechanism that continuously monitors supply water temperature and compares it against required water temperature thresholds. Based on this real-time feedback, the controller dynamically adjusts which gas compressors should utilize the exhaust heat recovery path, optimizing energy utilization while maintaining manageable control complexity through rule-based decision logic

Inventive Principle:
Principle #23Feedback

3Loss of energy

If exhaust heat is recovered from all gas compressors, then thermal energy efficiency is improved, but the risk of insufficient cooling when temperature is high increases

Engineering Contradiction:
Improvethermal energy efficiencyVSAvoidinsufficient cooling risk
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the exhaust heat recovery operation based on real-time temperature conditions. When supply water temperature exceeds certain thresholds or cooling demand increases, the controller selectively reduces or suspends heat recovery from specific compressors, ensuring adequate cooling capacity is maintained. This dynamic adjustment allows the system to maximize thermal energy efficiency under normal conditions while preventing insufficient cooling during high-temperature scenarios

Inventive Principle:
Principle #15Dynamics

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

Enhances thermal energy recovery efficiency by optimizing the use of exhaust heat across all gas compressors, reducing the need for additional cooling mechanisms and lowering overall system costs.

Implementation Method 1

a exhaust heat recovery equipment; and a controller, wherein further comprising a exhaust heat recovery path connecting the plurality of gas compressors and the exhaust heat recovery equipment

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4656878A1Exhaust heat recovery system
Publication Date: 2025.12.03 HITACHI IND EQUIP SYST CO LTD
  • EP4656878A1 patent drawingFigure 1
  • EP4656878A1 patent drawingFigure 2
  • EP4656878A1 patent drawingFigure 3

AI summary

An exhaust heat recovery system comprises: a plurality of gas compressors (3); an exhaust heat recovery equipment (2); and a controller (1), wherein an exhaust heat recovery path connects the plurality of gas compressors (3) and the exhaust heat recovery equipment (2), and the plurality of gas compressors (3) can select whether or not to use the exhaust heat recovery path based on instructions from the controller (1), the controller (1) compares a set required water temperature with a supply water temperature, which is the temperature of the water supplied from the exhaust heat recovery equipment (2) to the outside, and at least one of the plurality of gas compressors (3) is instructed to use the exhaust heat recovery path when the supply water temperature is lower than the required water temperature.