Fuel Cell Boiler Exhaust Integration for Hot Box Temperature Stability
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Solution Overview
Problem
Fuel cell systems face efficiency issues due to temperature variations caused by outside air introduction, leading to decreased power generation efficiency, and existing systems have complex structures with separate air intake and exhaust lines.
Innovation Solution
A combined fuel cell and boiler system that utilizes a latent heat exchanger to collect heat from exhaust gases, unifies air intake and exhaust lines, and uses exhaust gases to maintain the hot box temperature, thereby enhancing thermal efficiency and simplifying the system structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If outside air is introduced to cool the fuel cell, then the fuel cell temperature is controlled, but the hot box internal temperature is lowered causing decreased power generation efficiency
Solution Approach 1:
A heat exchanger is introduced as an intermediary device between the outside air and the hot box interior. The heat exchanger allows thermal energy transfer from exhaust gases to incoming air, mediating the temperature control function while preventing direct thermal impact on the hot box interior, thus resolving the contradiction between cooling needs and efficiency maintenance
Solution Approach 2:
The temperature parameter of the incoming air is changed through heat exchange with exhaust gases before entering the hot box. By preheating the air using waste heat from exhaust gases, the air temperature parameter is adjusted to avoid excessive cooling of the hot box interior, thereby maintaining power generation efficiency while still providing necessary cooling to the fuel cell
2Reliability
If separate air intake and exhaust lines are used, then air supply and exhaust functions are independent, but the system structure becomes complex
Solution Approach 1:
The air intake line and exhaust line are merged into a single dual-purpose duct system. The same physical structure serves both functions at different operational phases: during normal operation it functions as an exhaust line, and during startup it functions as an air intake line. This merging reduces the number of separate components while maintaining functional independence through operational sequencing
Solution Approach 2:
The exhaust line is designed with multi-functionality to serve as both an exhaust pathway during normal operation and an air intake pathway during startup. This universal design allows a single component to fulfill multiple functions that would traditionally require separate dedicated structures, thereby simplifying the overall system architecture
3Ease of manufacture
If exhaust gas heat is not utilized, then the system operation is simple, but thermal efficiency is low
Solution Approach 1:
The waste heat in exhaust gases, which would otherwise be discarded as a harmful energy loss, is converted into a beneficial resource by using it to preheat the incoming air through a heat exchanger. This transforms the harmful thermal energy loss into a useful heating function, improving overall thermal efficiency while adding minimal operational complexity
Solution Approach 2:
Instead of discarding the thermal energy contained in exhaust gases, the system recovers this waste heat through a heat exchanger to preheat the incoming air. This recovery process captures otherwise lost energy and puts it to productive use, thereby improving thermal efficiency without significantly complicating the system operation
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
The system effectively uses exhaust gas heat to maintain the hot box temperature, improving power generation efficiency and simplifying the system configuration by unifying air intake and exhaust lines, thus enhancing overall system efficiency.
Implementation Method 1
a latent heat exchanger (250) connected to an exhaust gas pipe (170) of the fuel cell portion (100), and collecting latent heat of exhaust gas of the fuel cell portion (100) together with latent heat of self-generated exhaust gas
Implementation Method 2
collecting latent heat of exhaust gas
Implementation Method 3
fuel cells have a structure in which electricity is generated by supplying fuels, such as hydrogen gas or hydrocarbon, to an anode and supplying oxygen to a cathode
Implementation Method 4
The reaction between hydrogen and oxygen in a fuel cell is an exothermic reaction, and thus generates heat
Implementation Method 5
a hot box for accommodating a fuel cell and a reformer
Data Source
AI summary
The present invention relates to a combined fuel cell and boiler system, and comprising: a fuel cell portion for receiving supplied outside air and raw material gas and generating electricity through a catalyst reaction; and a boiler portion comprising a latent heat exchanger, which is connected to an exhaust gas pipe of the fuel cell portion, for collecting the latent heat of self-generated exhaust gas with the latent heat of exhaust gas from the fuel cell portion. The present invention can effectively increase the efficiency of a boiler by supplying the exhaust gas from the fuel cell to the latent heat exchanger in the boiler, so as to be heat-exchanged in the latent heat exchanger with the exhaust gas from the boiler and then discharged, and can simplify the composition by unifying exhaust gas pipes.