Parallel Heat Exchanger Circuit for CHP Plant Heat Recovery Efficiency

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Combined heat and power plants face inefficiencies in heat recovery and utilization, with existing systems limited by the low conversion of chemical energy into electric energy, resulting in significant thermal energy waste.

Innovation Solution

A system connecting exhaust, cooling liquid, and lubrication oil heat exchangers in a parallel heating circuit with a district heating heat exchanger, allowing for improved control and maximal heat recovery by managing temperature differences and flow distribution, potentially eliminating the need for separate exhaust gas economizers/aftercoolers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If heat exchangers are connected in series, then heat recovery is maximized, but flow control and temperature management become difficult

Engineering Contradiction:
Improveheat recovery efficiencyVSAvoidflow control capability
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The heating circuit is segmented into multiple parallel channels, each containing different heat exchangers (exhaust heat exchanger, cooling liquid heat exchanger, lubrication oil heat exchanger). This segmentation allows independent flow control for each channel while maintaining overall heat recovery efficiency, resolving the contradiction between maximizing heat recovery and enabling flow control.

Inventive Principle:
Principle #1Segmentation

2Loss of energy

If temperature difference over heat exchangers is increased, then heat recovery is maximized, but risk of overheating components increases

Engineering Contradiction:
Improveheat recovery efficiencyVSAvoidcomponent temperature control
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system employs dynamic flow control where the heating liquid flow is divided among parallel channels with adjustable flow distribution. This dynamic control allows the system to optimize temperature differences across heat exchangers for maximum heat recovery while preventing any single component from overheating, thus resolving the contradiction between heat recovery efficiency and component temperature control.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If separate exhaust gas economizer/aftercooler is used, then exhaust gas heat recovery is improved, but system complexity increases

Engineering Contradiction:
Improveexhaust gas heat recoveryVSAvoidsystem component count
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The exhaust heat exchanger is merged into the parallel channel structure of the existing heating circuit, sharing the same heating liquid source and distribution system. This integration allows exhaust gas heat recovery to be achieved without adding separate economizer/aftercooler systems, thus resolving the contradiction between improving exhaust heat recovery and reducing system complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 the overall efficiency of heat recovery and utilization in combined heat and power plants by optimizing temperature differences and flow control, leading to improved heat transfer and reduced operational costs.

Implementation Method 1

an exhaust heat exchanger (2) is provided for recovering heat from exhaust gases (10) of the engine (1)

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

a cooling liquid heat exchanger (3) is provided for recovering heat from a cooling liquid circuit (30) of the engine (1)

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

a lubrication oil heat exchanger (4) is provided for recovering heat from a lubrication oil circuit (40) of the engine (1)

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 4

a district heating heat exchanger (5) for providing heat to a district heating consumer network (50)

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3077652B1System for recovering heat in a CHP-plant
Publication Date: 2017.10.11 WARTSILA FINLAND OY
  • EP3077652B1 patent drawingFigure 1
  • EP3077652B1 patent drawingFigure 2
  • EP3077652B1 patent drawingFigure 3

AI summary

A system for recovering heat from a combined heat and power plant comprising an internal combustion engine (1) and a heating circuit (60) for heating liquid (L) to circulate, said system comprising: - an exhaust heat exchanger (2) is provided for recovering heat from exhaust gases (10) of the engine (1), - a cooling liquid heat exchanger (3) is provided for re- covering heat from a cooling liquid circuit (30) of the engine (1), - a lubrication oil heat exchanger (4) is provided for re- covering heat from a lubrication oil circuit (40) of the engine (1), - said exhaust heat exchanger (2), cooling liquid heat exchanger (3) and lubrication oil heat exchanger (4) are connected in the heating circuit (60) having also a district heating heat exchanger (5) for providing heat to a district heating consumer network (50), - the cooling liquid heat exchanger (3) and the lubrication oil heat exchanger (4) are connected in a channel (601) parallel to a channel (602) wherein the exhaust heat exchanger (2) is connected, so that the heating liquid (L) flow after the district heating heat exchanger (5) can be divided in said parallel channels (601, 602).