High Compression Ratio Free Piston Engine for CHP
High-efficiency, low-emissions HCCI engine with linear generator for combine heat and power applications.
EtaGen, Inc.
Recipient
Menlo Park, CA
Recipient Location
13th
Senate District
24th
Assembly District
$796,148
Amount Spent
Completed
Project Status
Project Result
The recipient installed the piston-free piston engine and CHP test package at its Menlo Park, California facility in the spring of 2017. EtaGen published a final project report that includes the results of performance testing and operational data collection activities performed through the end of the project.
The Issue
Small-scale combined heat and power (CHP) systems have not been able to gain serious traction in the California market in part because existing CHP technologies lack the performance and cost attributes to provide a compelling economic solution for the majority of CHP-favorable commercial, institutional and industrial applications. The weaknesses of available technologies vary by type, but they include lackluster efficiencies, high capital and operating costs, and poor emissions performance. Low to modest electric efficiencies may lead to under sizing the systems electric capacity, or to incomplete thermal utilization in commercial applications with high electrical demand.
Project Innovation
This project designs, builds, and field tests an advanced generation CHP product that complies with the CARB 2007 emissions standards for distributed generation and exhibits higher electric performance over conventional natural gas-fired internal combustion engine CHP. Key to the project is the recipient's high compression, ratio free piston-engine: a homogenous-charge compression ignition engine that features a variable compression ratio and allows operators to maximize the engine's thermal efficiency relative to the peak combustion temperature. This minimizes the formation of NOx, which is characteristic for other piston engines. Oil-less operation also avoids formation of volatile organic compounds and reduces carbon monoxide (CO) formation. A key project goal is to achieve 40 percent electric efficiency and 80 percent CHP efficiency with a 50 kWe generator. The long-term goal is to achieve 45 percent electric and 85 percent CHP efficiencies for a 100 kWe commercial unit.
Project Benefits
Achieving high efficiency, low capital and maintenance costs, and superior emissions performance, with free-piston technology and heat capture will be economical where existing CHP technologies are not. Over a ten year period following commercial introduction, EtaGen estimates the following benefits for California: 699 MW in avoided new centralized generation capacity, 68 billion-cubic-feet in natural gas savings, $978 million in energy costs savings, and 4 million tonnes of CO2 emissions reduced.
Consumer Appeal
Linear generator technology offers a CHP solution for customers with low thermal to electric power ratios. High electric and thermal efficiencies also make it an attractive option for electric-only customers. Having a variable compression ratio, the linear generator fuel-flexible, allowing for operation with biogas without employing extensive fuel treatment as currently required for fuel cells and engines with catalysts.
Affordability
High electrical efficiency combined with low capital costs results in higher economic returns than current existing prime movers. Spark-less and oil-less operation reduce the frequency and cost of regular maintenance. Ultra-low criteria emissions at or below CARB standards reduces or even eliminates the need for NOx after-treatment, reducing the installed cost.
Economic Development
EtaGen estimates for the ten year period following full commercial introduction, the cumulative benefits to California include, 34 MMBTU natural gas savings from boilers, $3 billion electricity and capacity savings, 5,716 metric-ton CO2 emissions reductions, and 4 GW in avoided centralized generation.
Reliability
Having only two moving parts reduces the number of failure modes, significantly improving the reliability/availability when compared to existing prime movers.
Subrecipients
DE Solutions, Inc.
CoreStates Group
Taylor Engineering and Plumbing, Inc.
Braaten Electric, Inc.
Match Partners
Sempra Energy
