Micro-Cogeneration:Is There a KW in Your Future ?

Skip HaydenRenewable and Integrated Energy Systems

Better Buildings by Design 2010Burlington, February 2010

Natural ResourcesCanada

Ressources naturellesCanada

Integrated Energy Systems

Objectives• Appreciate what micro-cogeneration is

• Understand the range of advanced micro-cogeneration technologies now impending on the North American marketplace

• Understand the potential energy, environmental and system advantages offered by micro-cogeneration

• See how you may have your own kw in your future.

What are youlooking for

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CCHT: Canadian Centre for Housing Technologies

CCHT Research Houses

• Located in Ottawa and operated by three agencies – NRCan, NRC & CMHC

• Consists of two identical research houses and townhouse-type info-demo centre

• Houses Design Heat Loss – > 40,000 BTU/hr

• Both houses are under Simulated Occupancy Protocol

Microgeneration• A notion of generation both heat and power on site

to serve the thermal load <50kW th and electrical <30kW el plus the grid

• May employ any combination of electrical generation and storage technologies that are on or off grid

• Technologies – Stirling Engines, IC Engines, Fuel cells, microturbines, thermophotovoltaics, thermoelectrics, solar

• or combinations of the above

Micro-Cogen Concept

Benchmark Architecture (natural gas fueled, outdoor unit, current technology)

Intelligent Home

Load management

Inverter / Charger

Battery

DC Bus:

AC Bus:gridparallel

Cogeneration System

IC engine + 3 way catalystVariable Speed DC outputShaft driven heat pumpHydronic Interface

electricity from grid

fuel

managed AC loads

radiant floor heat

pool heat

weather inputs

occupancy inputs

space heating

domestic hot water

normal AC loads

Inputs: Outputs:

space cooling

distilled water (?)

Why Microgeneration?• Latest Advances in Building Technologies

• Security of Power Supply

• Control Over Assets

• Economics

• Reduce need for new power generation facilities

• Reduce GHG’s

Potential functions / specifications

• “Occasional Stand-By Service”:– Drawn from battery storage for a couple of hours max during occasional grid interruptions– Supplies managed loads such as refrigerator, freezer, well pumps, controls, alarms etc– Availability of about 1000 hours over 10 years– Competes with the idea of buying a gasoline generator – Can recharge during night at lowest grid rates (Ontario model)

• “ Peak Rate Avoidance & Emergency Service”:– Drawn from engine during daily peak electricity pricing period (Ontario model)– Supplies heating / cooling needs, domestic hot water and selected loads– Availability of 4 to 6 hours x 5 days per week resulting in 13,000 hours over 10 years– Satisfies need for independence and preserves occupant comfort during emergencies – Theoretical potential to zero out electricity bill

• “Continuous Cogeneration Service”– Stirling engines and fuel cells will run longer at lower capacity with higher inherent E/Q ratios– May need electricity storage even more than the IC engine option above – Non-reciprocating systems promise longer life with lower maintenance

• “Off-Grid Luxury Service”– Architecture suitable for integration of solar- PV / wind and solar- thermal – Propane or Bio-diesel capability for luxury market segment

Myths, Facts and Customer Mindset…

• Myths:– Grid interconnection is a must (it’s doubtful customers will invest

their own money to put electricity on the grid)– High electrical efficiency is a must (E/Q ratio is more significant)– 500 $/Kw must be attained (< 10 Kw it’s irrelevant, it’s the up front

incremental cost premium and monthly charges relative to other alternatives that counts – domestic cogeneration systems compete for disposable income like any other consumer purchase)

• Facts:– Reliability, low maintenance, low noise and low emissions are very

important • Customer Mindset:

– It’s an appliance - integrated products are essential– We are surveying how Canadian customers value each function– “independence”; “comfort” ;“value” and “image” may sell

Microgeneration – Technology Options

• PEM and SOFC Fuel Cells• Stirling Engines• Reciprocating Engines• Thermophotovoltaics• Thermoelectric• others

Proton Exchange Membrane (PEM) Fuel Cells

• Modulating output • Efficiency 35-45% • Pure H2 or external reformer• Field trials around the globe

Solid Oxide Fuel Cell (SOFC)

• Output 1-50 kW electric• Internal reforming• Efficiency 45-50%

Solid Oxide Fuel Cell Trial• Fuel cell operated for over 2 months. • Operating period covered

– mid-winter conditions (outdoor temperatures for a few days in the range of –10C to –20C)

– Shoulder season conditions –Spring 2005

– Summer conditions – several days with no space heating.

• Fuel Cell was in good operating condition throughout the project, and on its return.

• Fuel Cell demo project was successful as it met the objectives of the project.

Electrical Wiring

Power Generation and Load SatisfiedTest House Electricity Consumption and Supplies(Excluding Data Acqisition and Heat Dissipation)

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Fuel Cell Electricity supplied to House

Fuel Cell Electricity Exported to Grid

Utility Electricity supplied to House

CCHT Test House Consumption

20-Mar-05

19.148.40.6

19.7

Stirling Engine• External combustor• Close to mass production • Electric efficiency 10-25%• Large field trials in Europe• Seen as a replacement of

heaters and boilers (& Central Generating Plant)

External Combustor Cogeneration Stirling

Engine• Gaseous or Liquid (bio) Fuels – AC, and DC

“backbone”• Generates heat and electricity• Optimize BOP• Alternative renewable energy sources

EnMax Pilot – Calgary, December 2007

• AC WhisperGen generating 1kW, propane fired

•• Provided both heat and DHW to

the home this winter

• Integrated with radiant floor heating through a LatentoTM latent heat exchange thermal storage tank

Stirling Engine MicroCogen System with Electrical Storage

• Demonstrating combination system integration (forced air space heat and DHW)

• Investigating performance advantage of lithium-ion vslead-acid batteries

• Exploring economics and environmental impacts using typical house electrical and thermal profiles

Stirling Engine Trials

• 6 kW (~20,000 BTU/hour) heat generated

• 750W electrical generated; 575W useable on the grid

• 115kg; 400mm x 550mm x 850mm

• Startup time before core reaches 70°C ranges from 0 - 30 min, depending on setup. The shortest uses no cooling water until core is at 60°C

• Shutdown time is 20-35 mins. Shortest uses fresh cooling water and dumps the heated cooling water.

• Since startup and shutdown times are long, it is most efficient to run the engine continuously.

Stirling Engine Efficiency

IC engines

• Proven technology• Integration with forced air

and water based heating systems

• Electrical output 1-6 kWelect• Large field trials in Japan

Hybrid IC Sngle-Cylinder Engine – HE Condensing Furnace System

• Generate 1kW electric & 3.25/18kW thermal power (only heat –condensing)

• 50% of generated electricity was used to satisfy the house demand; the rest was exported to the grid

• Operated reliably and with high efficiency at CCHT for 4 weeks

• Second generation under development – modulating output and back up power + space/water heating

• Extremely quiet

Hybrid ICE/HE Furnace System –CCHT Results

Cost of Heating System Operation

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Climate Energy SystemHigh Efficiency FurnaceTwo Stage Furnace Locked to HighOutdoor Temperature

Breakdown of Electrical Supply and Demand

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Date and Time

Elec

tric

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From Engine

From Grid

House Electrical Demand

Exported Electricity

IC Micro-Cogen Aisin

• 6 Kw electric at 35% efficiency

• 10:1 turndown• Low NOx• Outdoor installation• Very long maintenance

interval

Borehole Storage to Manage Excess Heat

Micro-Cogen Integration

Micro-cogeneration technologies to supply space and water heating requirements, along with electricity at overall efficiencies of 90%

This potentially large (several million) distributed source would be a highly efficient way to reduce requirements for new large electricity generation with at least a 3-fold reduction in carbon emissions

Further coupling this with cost-effective borehole storage for heat and later extraction with a heat pump could further double the emissions reduction

Advanced, interactive smart controls are required to ensure optimally efficient energy generation and utilization within the residence and the grid

This is an important step on the road towards net-zero housing

PHEV (Plug-in Hybrid Electric Vehicleintegrated with house, micro-cogen and grid

PHEV feeding electricity back to grid during peak A/C demand

Micro-cogen unit

Micro-cogen system charging PHEV at night

Driving green and efficiently during day

Seasonal Storage for Excess Heat with

Micro-turbine

Thermophotovoltaics (TPV) & Thermoelectrics (TE)

• Ceramic, heated by flame with recirculation and evneO2 enrichment (membranes), becomes a highly luminous, tuned source, emitting light and generating electricity through a PV cell

• Self powered appliances• Cascading TPV and TE• Setting up commercial

prototype with client for water heating

Balance of plant• To provide optimal

operational conditions for optimal combined heat and power generation

• To be generic and simple*• To minimize the MG

interruptions • To minimize water heater

burner operation (cycling)

Vanadium-Redox Battery Energy Storage System (VRB-ESS)

• Canadian Manufacturer: VRB Power Systems Inc.

• First prototype unit shipped to customer site

• Specs: 3.3 kW max power output for 3 hours (10 kWh)

• Assess characteristics and performance

• Completed over 3000 hours and 120 full charge/discharge cycles at 60% depth of discharge

• No performance degradation observed so far

Efficiency 20 % x 30%

Conventional Fluorescent Lighting

Overall efficiency = 6%

CO2 equiv effic = only 3% (coal-fired electicity)

“Efficient”Lighting

Coal-fired Electricity Generation

Integrated GasLighting System

Eliminate need for electricity by generating light directly by burning natural gas in optimized visually-radiant burner as a central source in building

Distribute the light throughout the building by means of light pipes

Capture rest of heat for space/wtr htgCo-gen without electricity generation !

Opportunities for Micro-CHP

• The preliminary results are very promising

• Special attention should be given to building integration

• A suitable thermal cooling will broader the application

• An optimal control strategy based on AI technologies should be developed

• High electrical efficiency is of little importance

• Exported electricity must have some value

• Virtual utilities• Effective for peak shaving

capabilities• Potential for retrofit and

combination with existing energy systems

• Incremental for high efficiency

• Combination with alternative generation systems

Review of Objectives• Appreciate what micro-cogeneration is

• Understand the range of advanced micro-cogeneration technologies now impending on the North American marketplace

• Understand the potential energy, environmental and system advantages offered by micro-cogeneration

• See how you may have your own kw in your future.

This is a technology whose time is coming quickly

Microgen 2008

First International Conference and Workshopon

Micro-cogeneration Systems and ApplicationsApril 29-May 1, 2008

Ottawa, Canada

For further information,

contact me (Skip Hayden)

Senior Research Scientist,D/S&T Director

Integrated Energy SystemsSBC, CETCO, NRCan

1 Haanel DriveOttawa, Canada K1A 1M1

tel: (613) 996 3186fax: (613) 992 9335

e-mail: skip.hayden@nrcan.gc.ca