A High Efficiency Spark Assisted Compression Ignition

1 KWe Generator System with

Integrated Waste Energy Recovery

Air Squared Inc., Purdue University, Argonne National Laboratory,

Mississippi State University

PI: Bryce Shaffer (ASI), CTO

Revision 4

Team

System Integration

and Design

SACI Development

WER Development

Technology

Proposed ICE Improvements -

• Spark Assisted Compression Ignition (SACI) combustion of

NG.

• High compression ratios.

• EGR dilution - Increased specific heat ratios.

• Low combustion temperatures - Lower heat losses.

• ICE down-speeding - Higher torque operation.

GENSET with greater than 40% fuel-to-electricity

conversion efficiency.

• Develop a high efficiency (35%) natural

gas (NG) internal combustion engine.

Organic Rankine Cycle flow diagram.

• Proposed ORC System Improvements

• Regenerator for working fluid

preheat

• Superheat working fluid from

exhaust heat.

• Expander-Pump integration.

• Compact size

• Fewer components

• Lower cost

• Increased reliability

T-S plot for the ORC system. (Purdue)

• Develop a novel bottoming Organic Rankine

Cycle (ORC) with appropriate working fluid

for optimal (6%) Waste Energy Recovery

(WER)

Expander-Pump Assembly

Technical Progress – ICE

• GT POWER simulations

• Parametric studies on the effects of

compression ratios, valve timing, phi

(Φ), intake boost, and EGR quantified

at diff. spark timings.

• Engine Selection and Procurement

• Marathon engine - liquid cooled

NG Spark Ignited.

• Engine Testing

• Test setup fabrication and

functional testing.

Marathon engine test setup. (ANL)

Exhaust

Process Water

Marathon Engine

TestStand

Starter System: Battery

Data Acquisition

Exhaust Heat Exchanger

WaterBrake Dyno

Natural Gas

Intake System

Estop#2: TestStand

Dyno LoadControl

Dyno ReservoirExhaust

Condensate Collector

Marathon engine best baseline at 1200 rpm. (MSU)

Technical Progress – ORC/WER

• ORC Working Fluid Selection

• R1233zd(E)

• Operating Conditions Optimization

• Max η1st Law = 16%

• Predictive Performance Modeling

• Pre-Alpha Expander Testing

• ORC Architecture Layout

• Process and Instrumentation

• Test Stand Design

• CAD Modeling for Test Stand

Construction

ORC test setup schematic. (Purdue)

ORC Test Setup CAD Model

Technical Progress – ORC/WER• Expander

• Operating conditions

• Designing

• Fabrication/Assembly

• Testing

Operating Conditions

Inlet Pressure 2400 [KPa]

Inlet Temperature 275 [C]

Outlet Pressure 240 [KPa]

Mass Flow Rate 0.00308 [Kg/s]

Work Output 120 [Watt]

Specifications

Rotational Speed 1800 [RPM]

Suction Volume 0.8 [CC]

Volume Ratio 6.5 [-]Scroll expander mounted on the test setup. (ASI)

Pre-Alpha Scroll Expander Model

Technical Progress – System• System Thermal Analysis

• Use engine and ORC

simulation data

• Optimize working

conditions

• Preliminary CAD model

• Component solid models

• Component packaging

System CAD model showing outer shell and component packaging.

Lessons Learned

• Scroll Expander Design

• Design improvements to reduce leakage losses

• Single stage might be more suitable for low power & high pressure

application.

• System Transient Operation

• WER System - Start Up/

Shut Down

• Clutch/Valve Design

Belt drive arrangement between engine and ORC expander -

pump.

Next StepsInternal Combustion Engine

• Continue engine testing.

• Validate simulation models using the test results.

• Modify and test engine as per the proposed SACI concept.

• Implement SACI Model.

Waste Heat Recovery System/ORC

• ORC system will be fabricated and tested.

• Validate simulation models and make improvements.

Expander – Pump for ORC

• Alpha expander and pump assembly will be designed and fabricated.

• Performance testing will be carried out.

System

• Prepare system integration plan.

• Improve system CAD model.

Expander-Pump Assembly

ORC Test Setup CAD Model

Scope of Low Cost Natural Gas Pump

Several GENSET projects require pressurized natural gas (35 PSIG) at the inlet of their system. While natural gas pumps currently exist, ARPA-E has recognized the need for an smaller, inexpensive solution.

• Scope: Design, fabricate and test a Gen 1, Gen 2 and Gen 3 prototype with the following specifications.• Performance: 5 LPM at 35 PSIG (Inlet at 0.25 PSIG)

• Power: < 60W

• Cost Target: < $100 per unit

• Life: Same as GENSET (10 yrs)

• Proven Life: 3000 hrs

Thank You

Low cost motor Deep drawn aluminum outer housing