Cogeneration and

Thermal Chillers ..

ASHRAE National Capital Chapter.

Arlington, VA10/10/2012

Agenda

• Cogeneration Interest and Application Basics

• Equipment Matching

• Thermal Chiller Overview

• Steam Components & Turbines

Definition

• Cogeneration / Distributed Energy  ‐Generation of electrical power on a users site to provide/supplement utility power, by the use of natural gas, coal, oil, wood products, etc., as an energy source.

Basic CoGeneration

Fuel Source

Fuel Source

‐ OR ‐

Boiler SteamSteam Turbine

Engine Generator

Generator

A.

B.

Fuel Application

1.  What fuels could be used for Example A ?

2.  What fuels may be used for Example B ?

3.  Which example is most efficient in changing      Fuel BTU’s into KW ?

4.  Which should be used for a given site ?

Definition

• Combined Heat & Power (CHP) –Cogeneration with heat recovery, designed to achieve a useful thermal balance with the combined power generation and heat recovery.  Topping Cycle (Brayton Cycle)

The Executive Summary August 2012 Publication

‐

Combined Heat and Power

A Clean Energy Solution

                                            

Combined heat and power (CHP) is an efficient and clean approach to generating electric power and useful thermal energy from a single fuel source. Instead of purchasing electricity from the distribution grid and burning fuel in an on‐site furnace or boiler to produce thermal energy, an industrial or commercial facility can use CHP to provide both energy services in one energy‐efficient step. The average efficiency of power generation in the United States has remained at 34 percent since the 1960s — the energy lost in wastedheat from power generation in the U.S. is greater than the total energy use of Japan.

CHP captures this waste energy and uses it to provide heating and cooling to factories and businesses, saving them money and improving the environment. CHP is a commercially available clean energy solution that directly addresses a number of national priorities including improving the competitiveness of U.S. manufacturing, increasing energy efficiency, reducing emissions, enhancing our energy infrastructure, improving energy security and growing our economy. 

While CHP has been in use in the United States in some form or another for more than 100 years, it remains an underutilized resource today. CHP currently represents approximately 8 percent of U.S. generating capacity compared to over 30 percent in countries such as Denmark, Finland and the Netherlands.

http://www1.eere.energy.gov/manufacturing/distributedenergy/pdfs/chp_clean_energy_solution.pdf

District Energy . org

The International District Energy Association (IDEA) commends the White House for issuing an Executive Order, "Accelerating Investment in Industrial Energy Efficiency," which calls for greater deployment of combined heat and power (CHP) as a means to increase energy efficiency, reduce energy intensity and strengthen US manufacturing and industrial output.

IDEA President & CEO Robert Thornton stated, “We applaud the Administration’s leadership in urging our industry to work together to add 40 gigawatts of new CHP capacity by 2020.  CHP is a proven, cost‐effective approach to harnessing both useful heat and power from a single fuel source, leading to higher efficiencies, lower energy costs and reduced emissions – a triple win for the US economy.”

ACEEE – American Council for an Energy‐Efficient Economy

September 19, 2012Combined Heat and Power Could Replace up to 100% of Retiring Coal Plant Capacity in States across the Country

Coal‐powered generation is becoming increasingly uneconomic due to several factors: the increased cost of coal; the decreased cost of alternatives like natural gas; an aging and inefficient coal fleet; and the impact of new and forthcoming air quality regulations, which aim to reduce toxic pollutants and other substances harmful to human health and the environment.  An estimated 2 to 5 percent of U.S. electric‐generating capacity will retire due to the above impacts, most of it in the form of older and smaller coal plants that were built over two generations ago.

Back to Basics

CHP = Energy usage to the OINK

Where will the Energy for CHP come from?

• Coal?• Oil?• Gas?• Wood?

• All of the above, and more.

• ASHRAE Publications

• Application Guide for Absorption Cooling/ Refrigeration Using         Recovered Heat ‐ Product Code 90378

• Cogeneration Design Guide – Product Code 90392

• Fundamentals of Steam System Design – Product Code 98030

Combined Heat & Power-- CHP --

Design Principle:

“A Generator is a60% Efficient Boilerwith Free Electricity”

19

Thermally-Activated Cooling Technologies

Distributed GenerationTechnologies

I.C. Engine- Jacket / Exhaust -

Double-EffectAbsorption

Chiller

Microturbine- Exhaust -

Solid Oxide Fuel Cell

I.C. Engine- Jacket / Exhaust -

Single-Effect Absorption Chiller Desiccant

Technology

190ºF

360ºF

800ºF

600ºF Steam Turbine Centrifugal Chiller

Technology MatchPower Generation / Thermal Cooling

Gas-turbine

Turbine Generator

20

CHP Prime Movers

• Combustion Turbines  0.5– 10 MW• Microturbines   30 – 250 kW • IC Engines   30 kW – 5 MW• Fuel Cells   200 kW – 1 MW

• 65% ‐ 50% WASTE HEAT• 25% ‐ 40% Electricity

Combustion turbines (CT) provide high volume, high quality heat and are typically over 1 MW in size providing the most thermal energy volume.

Internal combustion engines (IC) provide high volumes of medium quality heat.

Micro turbines (MT) provide high volumes of low quality heat and are grouped together to provide sufficient waste heat.

1300 to 6130 KW Busbar Output$ 1,600,000 to $ 5,600,000 Installed Cost

240 to 4750 KW Busbar Output$ 230,000 to $ 2,900,000 Installed Cost

50 to 300 KW Busbar Output$ 120,000 to $ 550,000 Installed Cost

Selection of a generator - is often dependent on the characteristics of a technology at a particular size – all systems suffer a loss of efficiency as the size is reduced.

•Large CHP sites (over 1 MW) generally use combustion turbines.

•Medium sites (250 kW – 2 MW) use IC engines predominantly.

•Small sites under 250 kW required output use either IC engines or microturbines.

Generator Thermal Output

• Simple Cycle Combustion Turbine:High Volume, High Temp Exhaust (900 – 1000°F)

• Recuperated Microturbine:High Volume, Medium Temp Exhaust (500 – 600°F)

• IC Engine:Low Volume, High Temp Exhaust (900 – 1000°F)+ Hot Water (200 – 220°F)

• Fuel Cell (SOFC):Low Volume, Medium Temp Exhaust (600 – 700°F)

Break Period

Next – Thermal Chillers

25

Steam Turbine Chillers

• High & Low Temperature Activation,  307 – 600 F• High & Low Pressure Steam System, 60 – 300 psig• High Efficiency

700 to 5,000 Tons

Efficiency – 1.25 COP,

Compact footprint

High IPLV Efficiency – 1.8 COP

Condenser Water 3 GPM, 55 F

Chilled Water to 36 F

26

Absorption Chillers

Single Effect:• Low Temperature Activation, 180 - 260 F•Steam or Hot Water• Low Cost• Simple• Good Efficiency – 0.71 COP

Wide range of models from <100 tons to >1,500 tons

Chilled Water down to 38F

3.3 to 4.5 GPM Condenser Water, < 70 F

Large & Heavy, Slower Response

Double Effect:• High Temperature Activation, 350°F •Steam or Direct Fired• Higher Cost• More Complex• High Efficiency – 1.3 COP

Example ‐ 1,500 Tons  (3,500 kW) • Two‐stage absorption chiller is about  360 ft² (33.4 m²), 115,000lb (54430kg) 

• Centrifugal steam‐turbine chiller  190 ft² (17.7 m²), 84,000lb (38,180kg) • Equals 90% larger footprint , and 37% more weight for absorption 

10 ft

19 ft

30 ft

12 ftSteam

TurbineCentrifugal

Absorption

Footprint - Two-Stage Absorber Chiller vs. Centrifugal Chiller

Single Effect Absorber

IC Engine

Steam Turbine

Double Effect Absorber

100 90 80 70 60 50 40 30 20 10 0

IPLV 1.8

IPLV 1.5

2.0

1.0

1.5

2.5

0.5

0.0

Effic

ienc

y (C

OP)

Percent Load

IPLV 0.9

Part Load Efficiency

Electric motor driven centrifugal 6.10 1.53

ELECTRIC CENTRIFUGAL CHILLER COPSITE

COPSOURCE

THERMAL CHILLERS COP SITE

COPSOURCE

Absorption ChillersSingle stage 0.71 0.64Two stage direct fired 1.00 0.91Two stage steam fired  1.30 1.19

Steam Turbine Driven Centrifugal Chiller 1.25 1.15

Gas Engine Driven  Centrifugal Chiller   2.10 1.97

30

CHP Plant SizeAverage output of a based CHP plant.  Electric efficiencies vary for each 

generator type but do not impact CHP efficiency 

CHP System

Ther

mal

Te

chno

logy

Effe

ctiv

e Si

ze

Ran

ge

CH

P O

utpu

t Ef

ficie

ncy

HH

V

ISO

Ele

ctric

O

utpu

t

Chi

lling

Out

put

@ 4

4 F

& 8

3 F

Nom

inal

Ele

ctric

Ef

ficie

ncy

LHV

Configuration Model kW % kW Tons %

Large Combustion Turbine CHP Turbine 2.5 - 7 77% 4,890 2520 31%Small Combustion Turbine CHP Dbl Abs 1 - 2.5 69% 1,585 984 24%Lg. Microturbine CHP Dbl Abs 0.25 - 0.5 60% 357 160 27%Lg. Reciprocating Engine CHP Dbl Abs 1.5 - 5 50% 2,875 444 37%Sm. Reciprocating Engine CHP Slg Abs 0.25 - 5 58% 1,160 260 35%Sm. Microturbine CHP Slg Abs 0.25 - 0.5 44% 305 81 27%CHP Output Efficiency = (Total busbar kW + Cooling converted directly to kW) / Fuel Input (HHV)

CHP System

Ther

mal

Te

chno

logy

Effe

ctiv

e Si

ze

Ran

ge

Ther

mal

-Ele

ctric

R

atio

CH

P O

utpu

t Ef

ficie

ncy

HH

V

Configuration Model kW T/kW %

Large Combustion Turbine CHP Turbine 2.5 - 7 0.6 77%Small Combustion Turbine CHP Dbl Abs 1 - 2.5 0.7 69%Lg. Microturbine CHP Dbl Abs 0.25 - 0.5 0.5 60%Lg. Reciprocating Engine CHP Dbl Abs 1.5 - 5 0.2 50%Sm. Reciprocating Engine CHP Sgl Abs 0.25 - 5 0.3 58%Sm. Microturbine CHP Sgl Abs 0.25 - 0.5 0.4 44%

31

CHP Efficiency

• CHP Output Efficiency is generally higher for Combustion Turbine based CHP system than IC Engine based systems.

CHP Output Efficiency = (Total busbar kW + Cooling converted directly to kW) / Fuel Input (HHV)

Gas Heating Values

• Low Heating Value (LHV) Excludes the latent heat of condensation

• High Heating Value (HHV) Includes the latent heat of condensation

• LHV = 0.9 x HHV

Ambient Air

Exhaust

Hot Water

IC Generator with Jacket Water Heat Recovery

Building Air Handling

Unit’s

Chilled WaterSingle Stage Absorber

CHP with Recovered Hot Water

Water Return

Jacket Water HR

Heat Recovery Steam or Hot Water Generator

Ambient Air

Exhaust

Steam or Hot Water

IC Engine Generator with Jacket Water and Exhaust Heat RecoveryBuilding Air

Handling Unit’s

Duct Burner

Chilled Water

Two Stage Absorber or

Single Stage Absorber

CHP with Recovered Med. to Low Pressure Steam or Hot Water

Condensate / Water Return

Jacket Water HR

Exhaust HR

Heat Recovery Steam GeneratorCombustion

Turbine Inlet Air Cooling

GeneratorAmbient Air

Exhaust

Steam

Combustion Turbine

Building Air Handling

Unit’s

Duct Burner

Chilled Water

Ste

am C

onde

nsat

e

Steam Turbine Chiller or

Two Stage Absorber

CHP with Recovered Steam

AIR INLETFILTER

DIVERTERVALVEs

GASTURBINE

GENERATOR

EXHAUSTBYPASSSILENCER

SUPPLE‐MENTARYBURNER

HEATRECOVERYSTEAMGENERATOR(HRSG)

PROCESSSTEAM

Combustion/Gas Turbine CHP System

Gas Turbine

Inlet Air Cooling

38

University ApplicationHigh Efficiency CHP System with High Thermal Output

Fuel SupplyDump

Condenser

InletAir

Cooling

Duct Burner

Chilled WaterSupply/Return

CombustionTurbine

GeneratorSteamTurbineChillers

Condensate Return

Steam Supply

CoolingTowers

Heat RecoverySteam Generator

MainStackBypass

Stack

Steam HeatSupply/Return Fig. Taurus 60 / Steam Turbine CHP System

2800 Steam Turbine Centrifugal

CT

Heat Recovery Steam GeneratorCombustion

Turbine Inlet Air Cooling

GeneratorAmbient Air

Exhaust

Steam

Combustion Turbine

Duct burner

Chi

lled

Wat

er

Ste

am C

onde

nsat

e

Steam Turbine Generator

CHP with Recovered Steam

Engine Driven Centrifugal

or Direct Fired Absorber

Next ‐ Steam Components & Turbines

Break PeriodBreak Period

Turbine Talk

• Exhausting Turbines / Back Pressure Positive Pressure Exhaust

• Condensing TurbinesNegative Exhaust Pressure

• Common Applications (rotating equipment)Generators,  Chillers,  Pumps

Condensing

Turbine

Steam Exhaust 112 F

Steam Inlet375 F

Nozzle Valves

Lower Arc of Emission

Turbine Section

End-milled diaphragm (stationary segment), without vanes

Page 51

Condensing Turbine Steam SystemExhaust Trunk

Surface Condenser

Turbine

Speed

Steam SupplyLevel

Condensate ReturnCondensate Pump

Vacuum Pump

Air (at start)Wet Steam

Steam Surface CondenserExhaustSteam

Condenser Pump

Vacuum Pump

CoolingWaterIn

LevelControl

Condensate Out