Grid-Independent Heat Engine System for Resilient Power and Heat
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Solution Overview
Problem
Conventional heat generating systems for residences are grid-dependent and lack resilience during blackouts, as they require electricity to operate, posing a risk during winter months despite having a natural gas or oil combustion source.
Innovation Solution
A grid-independent heat engine system that utilizes a desorber, scroll expander, and resorber in a thermodynamic cycle with a working fluid like ammonia-water, generating electricity and heat from a low-temperature source, and includes a valve assembly for selective fluid injection to optimize energy conversion and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional natural gas furnaces are used for heat generation, then heat production is achieved, but the system becomes dependent on grid electricity and loses reliability during blackouts
Solution Approach 1:
The heat engine system generates its own electricity through the thermodynamic cycle operation, eliminating the need for external grid power. The expander converts thermal energy directly into electrical energy, allowing the system to serve itself during blackouts without requiring external electrical supply for operation.
Solution Approach 2:
The system utilizes phase transitions of the working fluid (ammonia-water mixture) through evaporation in the desorber and condensation in the resorber to drive the thermodynamic cycle. These phase changes enable continuous energy conversion from thermal to mechanical to electrical energy, ensuring reliable operation independent of grid power.
2Loss of energy
If grid-dependent heating systems are used, then infrastructure simplicity is maintained, but energy efficiency and sustainability are reduced due to lack of blackout insulation
Solution Approach 1:
The heat engine system maintains continuous operation during blackouts by converting thermal energy from the combustion source directly into electrical energy through the expander. The thermodynamic cycle continues uninterrupted, providing continuous heat and power without relying on external electrical infrastructure, thus eliminating energy loss associated with grid dependency.
3Productivity
If a thermodynamic cycle system with multiple heat exchangers is implemented, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The system merges the heat exchanger functions into integrated components: the desorber combines heating and separation functions, the resorber combines cooling and condensation functions, and the expander integrates power generation with thermal energy conversion. This merging reduces the number of separate components while maintaining high energy conversion efficiency through the thermodynamic cycle.
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 provides reliable power and heat generation independent of the grid, utilizing locally available fuels or solar thermal energy, enhancing energy efficiency and resilience against blackouts, with the ammonia-water mixture acting as both a coolant and lubricant, achieving higher efficiency compared to conventional systems.
Implementation Method 1
a first heat exchanger in fluid communication with a heat source for heating a working fluid therein
Implementation Method 2
an expander downstream the first heat exchanger and in fluid communication therewith for receiving the heated working fluid
Implementation Method 3
a second heat exchanger downstream the expander and in fluid communication therewith for cooling the working fluid received therefrom
Implementation Method 4
The ammonia-water mixture acting as both a coolant and lubricant
Implementation Method 5
The ammonia-water mixture acting as both a coolant and lubricant
Implementation Method 6
the expander comprises a shaft in operational communication with magnetic coupling for generating electricity
Data Source
AI summary
A heat engine system comprises a first heat exchanger, an expander, a second heat exchanger and a valve assembly. The first heat exchanger is in fluid communication with a heat source for heating a working fluid therein. The expander is downstream the first heat exchanger and is in fluid communication therewith for receiving the heat working fluid. The second heat exchanger is downstream the expander and in fluid communication therewith for cooling down the working fluid received therefrom. The valve assembly is in fluid communication with the second heat exchanger and the expander for providing for selectively injecting the expander with cooled working fluid from the second heat exchanger.