Integrated Plate Heat Exchanger for Exhaust Gas Water Preheating
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Solution Overview
Problem
Existing fuel-fired heating systems face challenges in space-saving integration of recuperators with minimal additional piping and low heat losses, as they often require separate components and suffer from inefficient heat exchange.
Innovation Solution
A plate heat exchanger with two partial heat exchangers is integrated into the system, where cold domestic water is first heated by exhaust gas in the primary heat exchanger and then further heated by heating water in the secondary heat exchanger, with additional heat sources like solar systems or condensate being integrated, and countercurrent flow enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a recuperator is added as a separate component to utilize further thermal energy from exhaust gas, then heat recovery efficiency is improved, but device complexity and spatial requirements increase
Solution Approach 1:
The patent combines the primary heat exchanger and recuperator into a single integrated plate heat exchanger unit. The plate heat exchanger serves dual functions: cooling exhaust gas for the heating circuit while simultaneously preheating service water using the cooled exhaust gas. This merging eliminates the need for separate recuperator components and reduces overall system complexity.
Solution Approach 2:
The plate heat exchanger is designed as a multi-functional device that handles multiple heat exchange tasks within a single structure. It simultaneously cools exhaust gas, preheats service water, and provides heating to the heating circuit, making one component perform the work of what would traditionally require multiple separate components.
2Loss of energy
If additional piping is used to connect separate heat exchanger components, then heat exchange functionality is improved, but heat losses and system complexity increase
Solution Approach 1:
By integrating the primary heat exchanger and recuperator functions into a single plate heat exchanger assembly, the patent eliminates the need for additional piping to connect separate components. The fluid channels are built into the plate structure itself, reducing piping requirements and associated heat losses.
3Loss of energy
If exhaust gas is cooled more extensively to maximize heat recovery, then energy efficiency is improved, but the temperature of exhaust gas becomes too low for effective heat transfer to heating water
Solution Approach 1:
The heat exchange process is divided into two sequential stages within the plate heat exchanger: first, exhaust gas is cooled by the heating circuit water in the primary heat exchanger section; second, the cooled but still warm exhaust gas further preheats service water in the recuperator section. This segmentation allows optimal heat recovery at each stage without over-cooling the exhaust gas.
Solution Approach 2:
The heating water is preheated by the exhaust gas before entering the main heating circuit, and service water is preheated by the cooled exhaust gas before further heating. This preliminary heating action maximizes the utilization of thermal energy at different temperature levels along the exhaust gas cooling path.
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 configuration achieves a high level of efficiency and reduces heat losses by preheating service water with cooled exhaust gas before further heating by heating water, allowing for space-saving integration with minimal additional piping.
Implementation Method 1
In the first partial heat exchanger, a first medium gives off heat to the medium to be heated
Implementation Method 2
cold domestic water as the medium to be heated is first heated in the first partial heat exchanger by exhaust gas cooled in the primary heat exchanger
Implementation Method 3
then heating water further heats the domestic water in the second partial heat exchanger
Implementation Method 4
heating water further heats the domestic water in the second partial heat exchanger
Implementation Method 5
countercurrent flow enhancing efficiency
Data Source
Figure 1
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AI summary
The invention relates to a plate heat exchanger (1) with parallel plates (30), between which media flow in the intermediate spaces and exchange heat via the plates (30), consisting of at least two sub-heat exchangers (11, 12). A first medium (31) which dispenses heat and a second medium (32) which absorbs heat alternately flow through the first intermediate spaces (16) between the plates (30) of the first sub-heat exchanger (11), and a second medium (33) which dispenses heat and the same medium (32) which absorbs heat alternately flow through the second intermediate spaces (17) between the plates of the second sub-heat exchanger (12). The third intermediate spaces (15) between the plates (30) of the first sub-heat exchanger (11) of the medium (32) which absorbs heat are connected to the intermediate spaces (15) between the plates (30) of the second sub-heat exchanger (12) of the medium (32) which absorbs heat so as to conduct fluid.