Energy Recovery: Saving Energy in Industrial Applications

Juan Manuel Moreno, LEED AP Project Manager Eaton’s Energy Solutions, Inc.

It’s rough recovering energy….

How I Hope to Keep You In This Room!!

• Industrial Energy Consumption in the USA • Fundamentals of Energy Recovery • Advantages of Energy Recovery in Industrial Processes • Boiler Flue Gas Energy Recovery • Gas Driven Chillers • CHP and CCHP • Energy Recovery With Heat Pumps • Desuperheaters • Energy Recovery with Organic Rankin Cycle

Industrial Energy Use in the U.S.

• Total industrial energy consumption = 30.6 quads • Approximately 55% for power & heat = 15.3 quads • 10-20% is avoidable waste • Approximately $6.00 per million Btu • $9.18 to $18.36 Billion Approximate Value of Waste

Fundamentals of Energy Recovery

Process that transfers waste energy of a system to the input material flow of the

same system or its surroundings

The waste energy has been paid for

Sensible and/or latent heat recovery is possible

User consumes the recovered energy as part of its process

Q = m Cp DT

Advantages of Energy Recovery in Industrial Processes

Advantages of Energy Recovery in Industrial Processes

High coincidence between cooling, heating and

electrical loads

Steam, hot water, chilled water and compressed air services required

Moderate to high operating hours >4,000 hours per year

Electric power quality and reliability are important requirements

High quality energy available

Boiler Flue Gas Energy Recovery

Flue Gas Energy Recovery

Air Recuperative Regenerative

Water Economizer Steam Generator

• Gas-to-gas heat exchanger

• Heat transfer from exhaust gas to air

• Thermal storage device • Giant heat wheel • Ovens, chemical reactors,

prime movers

• Similar to a boiler • Heat source is waste

energy from a process

• Installed in stack • Transfers waste heat to

feedwater or return water

Boiler Economizer - Application

Food manufacturing

Retrofitted a 4,000 MBH existing cast

iron hot water boiler Fuel: Propane

Total annual cost savings: $24,670 Simple Payback: 3.5 years

342 MBH recovered energy

Boiler Economizer Lessons Learned

Check existing system water conditions

• Proper oxygen levels • Check for solids, minerals and organic material

Determine if an economizer stack by-pass is required

• If economizer fails the boiler must be shut down. Is owner ok with this? • Is there a fully redundant boiler?

Can existing stack handle the additional pressure drop?

• Typical pressure drop 0.15 to 0.25 in WC

Leave enough room between boiler flue discharge and economizer for combustion ports

Gas Driven Chillers COPs between 1.8 to 2.9 with no

engine jacket heat recovery COPs between 1.9 to 3.16 with

engine jacket heat recovery Water cooled available from 150 tons

to 400 tons Air cooled available from 50 tons to

100 tons Free engine waste heat recovery

Gas Driven Chillers - Application

Food manufacturing plant

Simultaneous need for hot and

chilled water

Operation >8,000 hours per year

800 ton central chiller plant

2,600,000 KW-hr saved per year

Increase of 205,686 therms per year

$ 460,000 total cost savings per year

Simple payback 3.41 years

CHP and CCHP

Combined Heat and Power • Cogeneration • Simultaneous production of heat

and generation of electrical energy from a single fuel source

Combined Cooling Heat and Power

• Trigeneration • Simultaneous production of heat,

cooling and generation of electrical energy from a single fuel source

Benefits Increased system thermodynamic

efficiency Reduced carbon footprint Sustainable Lower total energy costs Improved power reliability and

quality

CHP and CCHP

Rules of Thumb Feasibility is high when: Cost of electrical energy above $0.06/Kwhr Greater than 5,000 hours of operation per year Simultaneous electrical and thermal energy loads

Prime Mover Selection Criteria T/E = 0.5 – 1.5 Internal Combustion Engines T/E = 1 – 10 Gas Turbines T/E = 3 - 20 Steam Turbine

CHP and CCHP Service IC

Reciprocating Engines

Gas Turbines

T/E Ratio

Hot Water 4 MBH/KW 5 MBH/KW

Steam 2 MBH/KW 5 MBH/KW

Absorption Chilled Water

0.25 TON/KW 0.35 -0.6 TON/KW

CCHP - Application

Ice manufacturing plant

Simultaneous need for electrical

and cooling load

Operation >8,000 hours per year

1.7 MW IC Gas Driven Engine

1,950,000 KW-hr saved per year

67% Annual Energy Cost Savings Simple payback 3.6 years

CCHP - Application

Ice manufacturing plant

Simultaneous need for electrical

and cooling load

Operation >8,000 hours per year

1.7 MW IC Gas Driven Engine

1,950,000 KW-hr saved per year

67% Annual Energy Cost Savings Simple payback 3.6 years

Energy Recovery With Heat Pumps

215˚F Supply air/water possible

with lower waste heat temperatures

Recover energy from chilled water central plants’ heat rejection and use for water heating, electric power generation

Recover low quality energy and boost it to higher , usable quality

Desuperheaters

Reduces refrigeration

operating costs by adding equivalent of 15% additional condenser capacity Heats water up to 180˚F

with waste heat Can be paired with other

technologies to produce higher quality energy

Energy Recovery with Organic Rankin Cycle

Waste heat to power

• Pressurized hot water • Saturated Steam • Hot gases

No emissions

Generation of up to 125KW

Heavy Industry • Glass • Cement • Chemical • Metals

Thank you!