Caribbean (CHP District Energy) Presented in the DistribuGen - - PowerPoint PPT Presentation

Development of the First Combined Heat and Power plant in the Caribbean (CHP–District Energy)

Apr pril il 7 7 - 9, 9, 20 2015 15 Hou Housto ston, T n, Texa xas Presented in the DistribuGen Conference & Trade Show for Cogeneration/CHP 2015

Colombs Energy

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This paper will be presented by: Alfredo Colombano from Colombs Energy, Bruce K. Colburn and Martin T. Anderson from EPS Capital Corp.

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CONSORCIO ENERGETICO PUNTA CANA MACAO (CEPM),

• Is a privately owned utility company engaged in generating, transmitting,

and distributing electricity through two isolated integrated power systems serving the fast growing tourism-based Punta Cana-Bávaro and Bayahibe regions in the Dominican Republic.

• Serves 60 hotels with approximately 35,000 rooms in these tourist

destinations as well as approximately 17,000 commercial and residential customers.

• Company’s installed capacity is 90 MWe with Wartsila and Hyundai diesel

engines operated using HFO.

• CEPM also supplies thermal energies (5,000 TR chilled water, hot water and

steam), with sales of:

• 700 GWhe/year of electric energy,
• 44 GWhcw/year of chilled water,
• 22 GWhdhw/year of domestic hot water.

CEPM EPM Ov Over ervi view ew

CEPM’s Facts

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District energy systems produce steam, hot water or chilled water at a central plant. The steam, hot water or chilled water is then piped underground to individual buildings for space heating, domestic hot water heating and air conditioning. As a result, individual buildings served by a district energy system don't need their

• wn boilers or furnaces, chillers or air conditioners. The district energy system does

that work for them, providing valuable benefits including:

What is a District Energy ?

 Improved energy efficiency  Enhanced environmental protection  Fuel flexibility  Ease of operation and maintenance  Reliability  Comfort and convenience for customers  Decreased life-cycle costs  Decreased building capital costs  Improved architectural design flexibility

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From: International District Energy Association (IDEA)

Energy - Efficiency Comparisons

From: International District Energy Association (IDEA)

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10 MWe (40%) 8 MWe 2 MWe 5 MWcw (1,421 RT) Fuel Oil Energy HFO 25 MW (100%) Chiller with electric compressor

Chilled Water production with Electric Chiller (Without Cogeneration)

COP 2.5

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8 MWe (40%) 5 MWcw 1,421 RT) Fuel Oil Energy HFO 20 MW (100%) 20% of reduction Absorption Chiiler COP 0.71

Chilled Water Production with Absorption Chiller (With Cogeneration)

7 MWth (35%)

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• As part of the expansion of CEPM’s services to an Energy Services

Company (ESCO), our team developed the First CHP-District Energy system in the Caribbean.

• This system provides 5,000 TR of chilled water (using Absorption Chillers)

and Domestic Hot Water (DHW) to Hotels located near to CEPM’s power plant.

• Waste heat comes from the exhaust gases and cooling water (Jacket water,

Oil Cooler, Intercooler) of Wartsila Diesel Engines 18V32 Vasa (6 MWe each) that consume Heavy Fuel Oil (HFO).

• The distance from the power plant and the different Hotels is about 2.5

miles (4 kilometers), making the new hot water loop a viable installation process.

CEPM’s CHP-District Energy Project Overview

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• Cooling is provided by locally based absorption chillers and the heat

exchanger used to produce DHW (Domestic Hot Water) for both cooling and domestic hot water were installed inside the hotels.

• The HTHW (High Temperature Hot Water) is produced in the power plant

with a temperature of roughly 248ºF (120ºC).

• At the hotel this HTHW supplies the thermal energy to drive single stage

absorption chiller units.

• The HTHW output after being used to provide chilled water via the

absorption chillers is then connected to an additional set of heat exchangers to produce DHW, and the “spent” HTHW loop temp water is then sent back to the power plant with a temperature of +/- 158ºF (70ºC).

CEPM’s CHP-District Energy Project Overview (cont.)

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• In this way a large delta T 90ºF (50ºC) can be effected by using the single

loop to serve two purposes, first high quality heat to run the absorbers, and second the lower temperature resulting water out of the chillers used for all or part of domestic hot water generation.

• The key goal and advantage of this project is to recover waste heat from

the operation of the existing diesel engines with an electric efficiency of 39.5%, and produce thermal energy which used to be wasted away and instead reuse part of it from the exhaust gases to create new economic value.

• Only about 16% of the heat is recoverable due to limitations imposed by

the dew point of the exhaust gases when HFO with 2.5 % Sulfur is used, about 25.2 % on the cooling water which is only recoverable to the level

• f about 9.1% , and the remainder is low temperature water used via

cooling water to dump heat, with roughly an additional 3% by radiation to the surrounding area.

CEPM’s CHP-District Energy Project Overview (cont.)

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• The sole reason the power company would consider this type of

additional new investment is that their system MWe load has been growing about 5% per year, so redeploying some electrical load into thermal does not really hurt their business economically, and the lower resulting lower utility costs to the resort hotels provides an economic incentive to those resorts to continue dealing with the utility, which

• therwise the resorts would not have to.
• All is economically done that benefits both the utility and the large

resorts, to say nothing of helping control costs to the other local customers (more and more local businesses and homes are connecting to this grid, some having had their own small generator systems, or connected to an adjacent power source).

CEPM’s CHP-District Energy Project Overview (cont.)

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CEPM’s CHP-District Energy Project Overview (cont.)

• The overall approach utilized as a business case was to “take over” the
• peration and maintenance responsibility at the resorts for the chiller

plants, including compressors, chilled water pumps, condenser water pumps, and cooling towers, as needed, and install new absorption chiller systems, and thermal heat recovery systems, so that in the end “chilled water, and domestic hot water heat” are being sold.

• The heating system was similar in that the existing boilers and pumps

were taken over by the utility, so that burden was removed from the

• resorts. The actual system results are sold as “thermal KWH” to the
• wners.

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• The existing electric chillers are still used in summer peaking via

electronic remote dispatch since there is insufficient heat through the loop for such peaks, but again, it is not relevant to the owner anymore since they buy delivered results. The paper will present the overall issues, and provide an overview of the results from this implementation process.

• It involved a few years of planning and budgeting, and securing written

long term agreements from enough resorts to get the project rolling, with the rest presumed to come aboard as new loads once they could see the facility in long term operation, as has occurred in other district heating projects in Europe and the USA.

• The project was completed in 30 months and has been in operation now

for 2 years.

CEPM’s CHP-District Energy Project Overview (cont.)

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CHP-District Energy Building Blocks

Diesel Engine or Heat Source

• Heat balance
• Waste Heat Quality

(Combustion Gases & Cooling Water Temperatures)

• Type of Fuel

Waste Heat Recovery Systems

• WHRU Gas & Water

side Corrosion Issues

• Combustion Gases

Dew point

• Load and

Temperature Control

• Water/Water Heat

Exchanger

Waste Heat Transmission & Distribution Circuit

• High Temperature

Hot Water Vs Steam

• Maximum pressures

& Temperatures

• Circuit Pressurization
• Differential

Temperature (Supply and Return)

• Variable Vs Constant

Flow

• Electric Energy for

Water Pumping

• Water Hammer &

Pressure Surge

• Water Chemical

Treatment Chilled Water Plant

• Single –Stage Vs

Double –Stage Absorption Chiller

• Electric Motor

Driven Compressor Chiller

• Adsorption Chiller

(future)

End Users (Hotels)

• Thermal Load

Hourly Profile

• Electric Load Hourly

Profile

• Thermal Base load

Vs Peak Load

• Thermal Energy

Storage?

• Thermal energy

Billing meter

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• 1

Wartsila

HT Cooling System LT Cooling System LT Cooling System HT Cooling System

Condenser Water Cooling Systems (Cooling Tower TowerTech)

Electric Driven Chiller Water Cooled Chilled Water Systems

Absorption Chiller (Broad)

Schematic of CEPM CHP-District Energy (Cooling/DHW )

EX3 EX2 EX4

248 ºF (120 ºC) Main Feeder Pumps 158 ºF (70 ºC)

Domestic Hot Water DHW Chilled Water (CW)

Expansion Tank 176 ºF (80 ºC) 140 ºF (60 ºC) 44.6 ºF (7 ºC)

Electric Driven Chiller Air Cooled

195.8ºF (91ºC) 122 ºF (50ºC) COP = 0.70

Diesel Engine or Heat Source Waste Heat Recovery System Chilled Water Plant Waste Heat Transmission & Distribution Circuit End Users (Hotels)

15 Data Collection and Analysis Load Characterization and Modeling Chiller Plants Design High Temp. Hot Water System Design Waste Heat Recovery System Design Impact over the CEPM Electric Load Economic Power Generation Dispatch Available Waste Heat from CEPM Power Generators

Project Main Activities

CAPEX and Cost of Service for Thermal Energies DHW Plants Design Tariff Negotiation with Hotels Optimization

16 Radiation 455.7 kW (3.0%)

Low Temperature Cooling Water 2,450 kW (16.1%) (*) (50C/122F) High Temperature Cooling Water 1,382 kW (9.1%) (*) (91 C/ 195F) Exhaust Gases Waste Heat Recoverable 2,430 kW (16%) (**) 350 C/ 662 F) Exhaust Gases Waste Heat Non Recoverable 2,430 kW (16%) 350 C/ 662 F) Electric Energy 6,000 kWe (39.5%)

Exhaust Gases 4,860 kW (32%) Cooling Water 3,832 kW (25.2%) 3,812 kW (25.2%)

Fuel Input HFO 15,190 kW (100%)

Diesel Engine Energy Balance (HFO)

6,000 kWe (39.5%) 9,812 kW (64.7%)

Notes: (*) Depend on the configuration of charge air coolers (One-stage or two-stage charge air cooler (**) Depend on the outlet temperature of exhaust gases from waste heat recovery boiler, limited by the Dew Point of the combustion gases (Sulfur %)

Diesel Engine or Heat Source

17 Radiation 455.7 kW (3.0%)

Low Temperature Cooling Water 2,450 kW (16.1%) (*) (50C/122F) High Temperature Cooling Water 1,382 kW (9.1%) (*) (91 C/ 195F) Exhaust Gases Waste Heat Recoverable 3,330 kW (21.9%) (**) 350 C/ 662 F) Exhaust Gases Waste Heat Non Recoverable 1,530 kW (10%) 350 C/ 662 F) Electric Energy 000 kWe (39.5%)

Exhaust Gases 4,860 kW (32%) Cooling Water 3,832 kW (25.2%) 4,712 kW (31.0%)

Fuel Input NG 15,190 kW (100%)

Diesel Engine Energy Balance (NG)

6,000 kWe (39.5%) 10,712 kW (70.5%)

Notes: (*) Depend on the configuration of charge air coolers (One-stage or two-stage charge air cooler)

Diesel Engine or Heat Source

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Waste Heat Recovery System

Waste Heat Recovery System 2,430 kWth (16%) 1,382 kWth (9%) 248ºF (120ºC) 170.6ºF (77ºC) Diesel engine Wartsila 18V32 Vasa HFO 662ºF (350ºC) 329ºF (165ºC) Fuel Oil Energy HFO 15,190 kW (100%) Exhaust Gases HEX3 WHRU HEX 2 All figures are indicative 6,000 kWe (39.4%) 195.8ºF (91ºC) 3,812 kWth (25%)

662.0 331.0 296.5 250.0 248.0 194.5 194.5 170.6 195.8 187.6 50 100 150 200 250 300 350 400 450 500 550 600 650 700

WHRU Hot end WHRU Cold end HEX2 Hot end HEX2 Cold end

Temperature ºF

Exhaust Gases Temperature WHRU Water Temperature High Temp. Hot water Temperature HT Circuit Temperature to HEX2 HFO # 6 100 %

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Waste Heat Recovery Systems Temperature Profile

Waste Heat Recovery System HT Cooling Water This temperature is limited by the minimum metal temperature in the tube This temperature is limited by the Flue Gases Dew Point temperature

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To avoid corrosion of the tubes, we must limit the outlet temperature of the exhaust gases recovery unit so that the temperature in the metal tube is not below the dew point exhaust gases, for example a sulfur content of 2.5% the curve indicates 93.3 C (200 F), while more will lower the temperature of the exhaust gases more heat is recovered but is limited by the dew point.

Minimum Design Tube Metal Temperature

Waste Heat Recovery System

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Minimum Design Tube Metal Temperature

Other literature indicates conservative values ​of the design temperature of tube metal. In this case to a sulfur content of 2.5% the curve indicates about 121.1 C (250 F), this fuel which take the value to adjust the water inlet temperature to the recovery unit, the temperature of the surface of the tube exposed to the exhaust gases tends to this value.

From: Steam 41th Edition The Babcock & Wilcox Company

Waste Heat Recovery System HFO

Business Model Option 1

• Produce High Temperature Hot Water (HTHW) 248 ºF (120ºC)
• Produce Chilled Water (CW) in power plant at CEPM 44.6 ºF

(7ºC) 5,000 TR

• Distribute Chilled Water (CW) to the hotels

This option seems more expensive, because the temperature differential is only 9ºF (5ºC), which implies a large flow circulating (13,333 GPM) in the distribution net work and therefore larger pipe diameters (Diameters 24 to 30 inches)

Chilled Water 44.6 -53.6ºF (7 - 12ºC) 5,000 TR 17,585 kWr 13,333 GPM Delta T = 9ºF (5ºC)

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High Temperature Hot Water (HTHW) 248 - 176ºF (120 - 80ºC) 25,121 kWte 2,381 GPM Delta T = 72ºF (40ºC)

COP = 0.70

Waste Heat Transmission & Distribution Circuit

Business Model Option 2

• Produce High Temperature Hot Water (HTHW) 248ºF (120ºC)
• Distribute High Temperature Hot Water 248ºF (120ºC)
• Produce Chilled Water (CW) 44.6ºF (7ºC) in each hotel 5,000 TR
• Produce Domestic Hot Water (DHW) 140 ºF (60ºC) in each

hotel This option seems less expensive, because the temperature differential is 72ºF (40ºC), which implies a small flow circulating (2,198 GPM) in the distribution net work and smaller pipe diameters (Diameters 14 to 16 inches) This option also allows to supply Domestic Hot Water to the hotels

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High Temperature Hot Water (HTHW) 248 - 158ºF (120 - 70ºC) 31,402 kWte (include 6,280 kWte for DHW) 2,381 GPM Delta T = 90ºF (50ºC) Chilled Water 44.6 -53.6ºF (7 - 12ºC) COP = 0.70 COP = 0.70 COP = 0.70

Waste Heat Transmission & Distribution Circuit

24 Waste Heat Transmission & Distribution Circuit

Advantages of HTHW over steam heat distribution systems:

• The amount of blow down required by a boiler depends on the amount

and nature of the makeup water supplied. HTHW systems have closed circuits, require little makeup, therefore, practically never require blow down whereas steam systems commonly lose about 1% to 3 percent of the total boiler output because frequent blow downs are required. Operation within closed circuits permits reducing the size of water treating systems to a minimum

• Due to the heat storage capacity of HTHW systems (large mass of water),

short peak loads may be absorbed from the accumulated heat in the system.

• The closed recirculation system reduces transmission and thermal losses

to a minimum while practically eliminating corrosion and scaling of generators, heat transfer equipment, and piping.

• Both supply and return high temperature water piping can be run up or

down and at various levels to suit the physical conditions of structures and contours of the ground between buildings without the problems of trapping and pumping condensate High Temperature Hot Water (HTHW) System Vs Steam System:

Chilled Water 1,000 kW (284 TR) (44.6ºF/7ºC)

COP = 3 Chilled Water Plant

Where QC is the heat removed from the cold reservoir. W is the work or heat consumed by the heat pump.

Coefficient Of Performance (COP)

QC W

Electric Motor Driven Centrifugal Compressor Chiller

Electric Motor Driven Centrifugal Compressor Chiller Energy Balance

Electric Energy 333 kWe

Cooling Water 1,333 kW 25

High Temperature Hot Water 1,428 kW (248ºF/120ºC) (Minimum 208ºF/98ºC) Chilled Water 1,000 kW (284 TR) (44.6ºF/7ºC) Electric Energy 5 kWe

Single-Stage Hot Water Absorption Chiller Energy Balance

Cooling Water 2,433 kW COP = 0.7 Chilled Water Plant

Where QC is the heat removed from the cold reservoir. W is the work or heat consumed by the heat pump.

Coefficient Of Performance (COP)

QC W

Single-Stage Hot Water Absorption Chiller

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Chilled Water 1,000 kW (284 TR) (44.6ºF/7ºC) Electric Energy 10 kWe

Double-Stage Hot Water Absorption Chiller Energy Balance

COP = 1.4 Chilled Water Plant

Where QC is the heat removed from the cold reservoir. W is the work or heat consumed by the heat pump.

Coefficient Of Performance (COP)

QC W

Double-Stage Hot Water Absorption Chiller

High Temperature Source 714 kW (356ºF/180ºC)

Cooling Water 1,724 kW 27

28 End Users (Hotels)

Cooling Monthly Profile

100 200 300 400 500 600 700 800 900 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC CDD (ºF)

Punta Cana Cooling Degree Day CDD

The cooling load is highly correlated with the Cooling Degree Day CDD and in a hotel is also influenced by the room occupancy

29 End Users (Hotels)

Cooling Load Vs. DHW Load Hourly Profile

As shown there are two peaks in demand for DHW (red line) one at 8:00 and

• ne at 18:00, these peaks do not coincide with the peak cooling demand

therefore HTHW demand that drives the absorption chiller; in order to exploit the maximum of the thermal energy from HTHW circuit that leaves the absorption chillers to heat the DHW, tanks are used to store thermal energy during off peak hours.

• 200

400 600 800 1,000 1,200 1,400 1,600 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00

Load kW

Day's Hours

Typical Hotel CW and DHW Load Profile

CW Load (kW) DHW Load (kW) HTHW for Abs Chiller

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 Reduction of 25% of the electrical energy (kWh) consumed by the resorts

versus the option of not cogeneration, this is because about these resort group consumed 34% of the electrical bill to produce chilled water before the district project energy was implemented. This implies that the utility consume 25% less fuel to supply electric power to these resort group and can delay the expansion of electrical transmission and distribution networks.

 The base demand for chilled water of the resorts was covered by the new

absorption chillers plus reuse of limited amount of existing peak cooling with the current older electric chillers.

 All demand for domestic hot water was supplied to the resorts group by

the district energy, therefore the fuel consumption in the domestic hot water boilers was reduced to zero. This is meaningful given that all were

• perated from Diesel or GLP, which is very expensive.

The results of this project to date can summarize as follows:

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 The overall COP of the systems with pumps, fans, compressors before was

about 2.7, and the overall system after around COP=15 in winter, and about 7 or so for 365 days (due to the reuse of the older electric chillers for peaking purposes). The business case required that the resort owners sign long term contracts to insure the new cogen system loop and appurtenance s could be appropriately amortized..

 This project demonstrated that you can use waste energy to produce

thermal energies (chilled water and domestic hot water) required in the resorts for the comfort of its customers, in such a way that both the resorts benefit through total cost reduction as compared to the previous all electric load case, and the utility wins through actually increasing net revenues in a cost effective way which helps to cement a long term relationship with large key customers. This then becomes truly a win-win situation for all, which is one of the avowed goals of any third party cogeneration project.

The results of this project to date can summarize as follows:

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Fuel Oil and Greenhouse Gas Emissions Reduction

With this cogeneration approach, about 25% of thermal energy is recovered to drive absorption chillers and DWH heat exchangers and reduce the Fuel consumption by 35,740 Bbl/year of HFO and 32,881 Bbl/year of LPG. The Greenhouse gas emission is reduced by over 28,872 metric tons CO2/year.

Greenhouse Gas emission reduction effects Chilled Water Production

Absorption Chillers TR 5,000 Electric Chillers Displaced TR 5,000 Electric Chillers Displaced kWcw 17,585 Coefficient Of Performance (weighted) COP 6.0 Electric Power for Chillers Displaced kWe 2,931 Load Factor 0.95 Electric Energy for Chillers Displaced MWhe/year 24,390 GHG emission factor for HFO Power Generation tCO2/Mwhe 0.8084

Avoided CO2 emissions tCO2/year 19,716 Avoided Fuel Oil (HFO) Bbl/year 35,740

Domestic Hot Water Production

Domestic Hot Water Production displaced from boiler kWdhw 6,280 Load Factor 0.50 Domestic Hot Water Production displaced from boiler MWhdhw/year 27,506 GHG emission factor for LPG tCO2/MWhdhw 0.3329

Avoided CO2 emissions tCO2/year 9,158 Avoided Fuel (LPG) Bbl/year 32,881 Total Avoided CO2 emissions tCO2/year 28,874

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Questions?

Alfredo Colombano BSIE, MBA, CEM, DGCP, REP Engineering Director Colombs Energy +1 281 686 2083 alfredo.colombano@colombsenergy.com alfredo.colombano@usa.net Bruce K. Colburn PhD., P.E., CEM, DGCP Project Energy Efficiency Engineer EPS Capital Corp. +1-610-525-4438 bcolburn@epscapital.com Martin T. Anderson Energy Efficiency Engineering Manager EPS Capital Corp. +1-610-368-3703 manderson@epscapital.com