Bottoming Cycle for Small Diesel Engines
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Solution Overview
Problem
Small internal combustion engines used for power generation produce low-temperature exhaust gas effluent streams, making it inefficient to utilize waste heat effectively with conventional bottoming cycles, which require large capital investments and are not suited for small engines.
Innovation Solution
A simple closed-cycle bottoming system incorporating a turbine, condenser, heat exchangers, and a recuperative heat recovery vapor generator to extract energy from exhaust streams up to 900°F, utilizing a multi-component working fluid to convert partially vaporized streams into fully vaporized and superheated streams for energy extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional bottoming cycles are used to utilize waste heat from small internal combustion engines, then waste heat can be recovered, but large capital investments are required and the system complexity increases
Solution Approach 1:
The system divides the waste heat recovery process into distinct functional modules: a vapor generator for phase change, a separator for fluid separation, and a turbine for energy extraction. This segmentation allows each component to be optimized independently and simplifies the overall system architecture compared to conventional bottoming cycles.
Solution Approach 2:
The invention utilizes multi-component working fluids with varying compositions (lean, rich, very rich solutions) to optimize heat transfer and expansion characteristics. By changing the compositional parameters of the working fluid, the system achieves efficient waste heat recovery without requiring complex system configurations.
2Loss of energy
If conventional bottoming cycles are used with small internal combustion engines, then waste heat can be utilized, but the capital investment increases
Solution Approach 1:
The system employs a simple vapor generator design that can be manufactured at lower cost compared to conventional bottoming cycle equipment. The use of multi-component working fluids allows for simpler, more affordable heat exchanger designs that effectively recover waste heat from small engines without requiring expensive specialized components.
3Temperature
If the exhaust stream temperature is reduced to below 900°F, then the heat recovery efficiency decreases, but the exhaust gas can still be utilized for power generation
Solution Approach 1:
The vapor generator utilizes phase transition of the multi-component working fluid (liquid to vapor) to absorb heat from the exhaust stream. This phase change process enables effective heat recovery even at lower exhaust temperatures below 900°F, as the latent heat of vaporization provides an additional heat transfer mechanism that maintains efficiency.
Solution Approach 2:
The system employs multi-component working fluids composed of multiple substances with different thermal and vaporization characteristics. These composite working fluids are specifically designed to optimize heat absorption from low-temperature exhaust streams, enabling efficient energy recovery at temperatures below 900°F that would be insufficient for conventional single-component systems.
4Device complexity
If a simple bottoming cycle is used with small internal combustion engines, then the system complexity is reduced, but the power generation capability must be optimized
Solution Approach 1:
The system incorporates dynamic control mechanisms that adjust the working fluid composition ratios and flow rates based on operating conditions. This dynamic adaptation allows the simple bottoming cycle to maintain optimal power generation capability across varying load conditions, compensating for the reduced system complexity through intelligent control rather than additional hardware.
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 significantly improves power generation capability by converting intermediate temperature waste heat into usable energy, achieving a 28% increase in power output compared to conventional Rankine cycles, with a more efficient and cost-effective means of harnessing waste heat from small diesel engines.
Implementation Method 1
a recuperative heat recovery vapor generator designed to extract energy from an exhaust stream having a temperature not greater than about 900° F. to convert the partially vaporized working fluid stream into a fully vaporized and in certain embodiment superheated working fluid stream
Implementation Method 2
a turbine for extracting energy from a fully vaporized multi-component working fluid
Implementation Method 3
a condenser
Data Source
AI summary
System and method is disclosed to increase the efficient of internal combustion engines using to generate electric power, where the system and method converts a portion of thermal energy produced in the combustion process to a usable form of energy.