Grid-Independent Micro-CHP System with Integrated Heat Recovery
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Solution Overview
Problem
Traditional CHP and mCHP systems are limited by their need for integration with an existing electrical grid, are not well-suited for remote installations, and do not efficiently capture thermal energy, which is typically discarded as waste.
Innovation Solution
A grid-independent mCHP system utilizing a liquid-cooled variable speed engine and generator, with a coolant loop and heat exchangers to reclaim thermal energy from multiple sources, and an alternator for battery charging and load sensing, capable of operating off-grid and generating 0.5-5 kW of electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional CHP systems are integrated into the existing electrical grid, then revenue can be generated by selling excess power and backup electrical source is provided, but the systems are limited in installation locations and require grid connection infrastructure
Solution Approach 1:
The patent extracts the mCHP system from the conventional grid-dependent configuration and creates a standalone off-grid system. The system removes the requirement for grid connection infrastructure by incorporating independent power generation (engine-generator set), autonomous control systems, and integrated heat recovery components that function independently of external grid infrastructure.
Solution Approach 2:
The mCHP system is designed to perform multiple functions in a single integrated unit: electrical power generation, thermal energy recovery, domestic hot water production, and space heating. This multi-functionality allows the system to operate effectively in diverse locations without requiring separate infrastructure for each function, thereby increasing installation location flexibility while managing device complexity through integration.
2Loss of energy
If thermal energy is recovered from engine exhaust and coolant, then fuel efficiency is improved and waste heat is utilized, but the system complexity increases with additional heat exchangers and coolant loops
Solution Approach 1:
The patent merges the heat recovery functions into the existing engine cooling system by integrating a heat exchanger that utilizes the engine's coolant loop. This approach combines waste heat recovery with the necessary engine temperature control function, allowing thermal energy recovery without adding completely separate cooling infrastructure. The system recovers heat from both exhaust gases and coolant, merging multiple heat sources into a unified domestic hot water and space heating system.
Solution Approach 2:
The coolant loop serves dual functions: maintaining engine operating temperature and providing a heat source for thermal energy recovery. The integrated heat exchanger system simultaneously provides domestic hot water and space heating, making the heat recovery subsystem multi-functional rather than adding separate systems for each thermal application.
3Adaptability or versatility
If the system is designed for remote off-grid locations, then accessibility to electricity is improved, but the system must be completely self-sufficient without grid backup
Solution Approach 1:
The mCHP system is designed to be self-sufficient by generating its own electrical power through the engine-generator set and recovering its own thermal energy needs through the integrated heat exchanger system. The system serves itself for both power and heat requirements, eliminating dependence on external grid infrastructure. The autonomous control system manages operation without external oversight, and the battery charger provides self-charging capability during operation.
Solution Approach 2:
The system incorporates a battery-powered starting system that provides cushioning for cold starts and startup power requirements. This beforehand preparation ensures reliable engine startup in remote conditions without requiring external power sources. The system also includes provisions for fuel storage and thermal energy storage to cushion against variations in load and environmental conditions.
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 maximizes thermal energy recapture, provides reliable off-grid power and heat, and minimizes maintenance, supporting basic needs and economic activities in remote areas.
Implementation Method 1
a liquid cooled generator that may comprise an alternator
Implementation Method 2
A coolant loop includes a recuperator that reclaims heat from both the engine and the generator
Implementation Method 3
A coolant-to-water heat exchanger, disposed downstream of the recuperator, cools the coolant back to approximately its first temperature while heating water in the water circuit
Data Source
AI summary
A grid-independent micro-combined heat and power system supplies heat and electricity to a building or a small number of buildings and can operate completely independently of a central-type electrical power grid. The system includes a variable speed liquid-cooled engine and a liquid-cooled generator that is configured to output an electrical supply of between approximately between 0.5 kW and 40 kW, a coolant loop, and a water circuit. The coolant loop heats a liquid using claimed heat from the genset to heat water that can be utilized as a domestic hot water source for cooking or cleaning or for a hot water source for heating. The speed of the engine may be controlled to control the output of the genset to meet prevailing electrical loads. The system may be part of a microgrid incorporating several such systems that are in electrical communication with one another and that collectively supply electrical power and heat to from a few buildings to about one hundred buildings.