operating an efficient district cooling plant in water

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Johnson Controls, Inc. —

WILL START ON THE HOUR 5:00 pm GST 8:00 am EST 1:00 pm GMT

Operating an Efficient District Cooling Plant in Water-Stressed Regions Part 1: The Energy-Water Nexus

Johnson Controls, Inc. — 2

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Johnson Controls, Inc. —

International District Energy Association November 19, 2014 Roy Hubbard Johnson Controls, Inc.

Operating an Efficient District Cooling Plant in Water-Stressed Regions Part 1: The Energy-Water Nexus


Agenda

Why do we need air conditioning?

How does air conditioning work?

How does water play a role in air conditioning?

What roles do weather and climate play in air conditioning?

How can saving energy save water?

What can we do to save energy?

What are the two main choices in air conditioning heat rejection systems?


Definition: Energy Balance

Energy In

Energy Out

Thermodynamics Law #1

The flow of heat is a form of energy transfer


Definition: Sources of Energy in a Building

Thermal Loss

Thermal Gain LIGHTING

PEOPLE

EQUIPMENT / PLUG LOAD

INFILTRATION / EXFILTRATION

VENTILATION

HVAC EQUIPMENT

BUILDING ENVELOPE

SOLAR HEAT GAIN


Definition: Sources of Energy in a Building

Thermal Loss

Thermal Gain LIGHTING

PEOPLE

EQUIPMENT / PLUG LOAD

INFILTRATION / EXFILTRATION

VENTILATION

HVAC EQUIPMENT

BUILDING ENVELOPE

SOLAR HEAT GAIN

Air conditioning allows buildings to be habitable

KEY CONCEPT

The purpose of Air Conditioning is to move unwanted heat from one area (building) to a location

less objectionable (outside)


How Air Conditioning Systems Move Energy / Heat

Building Energy

Air Handler Fan

Water-Cooled Chiller

Cooling Tower

Air Handler Coil

Atmosphere

Building Energy

Air Handler Fan

Air-Cooled Chiller

Air Handler Coil

Atmosphere

AIR

-CO

OLE

D

WAT

ER-C

OO

LED

= air transfer

= water transfer

= refrigerant transfer


Definition: Dry Bulb and Wet Bulb

DRY BULB (DB) Temperature of air

measured by a thermometer

Exposed to the air but shielded from radiation and moisture

WET BULB (WB) Minimum temperature

achieved by evaporative cooling

Largely determined by the DRY BULB temperature and HUMIDITY (moisture)

Air-Cooled System

Water-Cooled System

46°C

24°C


Definition: Air-Cooled Heat Rejection

Air-Cooled System Air-Cooled Radiator

LIQUID OUT

LIQUID IN

AIR IN

WARM AIR OUT


Definition: Evaporative Cooling

Heat Energy +

Water Vapor Molecules

When EVAPORATION occurs, heat is removed from an object that is being cooled.


Definition: Water-Cooled Heat Rejection

Body Evaporation Evaporative Cooling Tower

Heat energy +

water vapor molecules


Definition: Psychrometric Chart

Weather Data Location:RIYADH, ALL REGIONS, SAUDI_ARABIA

Weather Hours0 to 10 to 10 to 10 to 10 to 10 to 10 to 10 to 10 to 1

0 5 10 15 20 25 30 35 40 45 50 55 60DRY BULB TEMPERATURE - °CChart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com

15%

25%

2%4%6%8% RELATIVE HUMIDITY

10% RELATIVE HUMIDITY20%30%40%50%60%70%80

%

90%

5

5 10

1015

15

20

20

25

25

30

30

35 WET BULB TEMPERATURE - °C

35

Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.comChart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com

Dry

Bul

b


Psychrometric Chart for Air-Cooled Systems

Air-Cooled System

LIQUID OUT 54°C

LIQUID IN

60°C

AIR IN 46°C

WARM AIR OUT

57°C




15%

25%



%

90%

5

5 10

1015

15

20

20

25

25

30

30


35


46°C 57°C





15%

25%



%

90%

5

5 10

1015

15

20

20

25

25

30

30


35


Psychrometric Chart for Water-Cooled Systems

Water-Cooled System

37°C dB 24°C wB

33°C dB 33°C wB


Air-Cooled vs. Water-Cooled Heat Rejection

Design day is based on DRY BULB temperature

Consumes no water (no evaporative cooling)

Large footprint

Design day is based on WET BULB temperature

Consumes water (evaporative cooling process uses water)

80% LESS AIR FLOW

Air-Cooled System

Water-Cooled System

KEY CONCEPT

Evaporative cooling enables water-cooled

systems to use less energy at the cost of water

consumption.


Definition: Energy Use and System Lift

Load (weight of the rock)

Lift

(hei

ght o

f the

mou

ntai

n)


E N E R G Y

Lift

Definition: Energy Use and System Lift

Load


Energy Use and System Lift - DESIGN DAY

100%

E N E R G Y

Per AHRI: Design Day conditions occur only 1% of the year

Des

ign

Lift

Design Load



Air-Cooled System

Water-Cooled System



Air-Cooled System

Water-Cooled System

46°C

DES

IGN

LIF

T

DES

IGN

LIF

T

24°C

KEY CONCEPT

There are multiple ways to save energy in a chiller plant that are

weather related:

1. Reduce the 2. Reduce the size of the load system lift

(weight of the rock) (height of the mountain)


Weather Data - Riyadh, KSA

RIYADH, KSA


Weather Data - Riyadh, KSA

28 31

35 40

43 45 46 45 43 39

33 28

17 18 19 21 21 20 22 23 21 20 19 18

05

101520253035404550

Dry Bulb (C)Wet Bulb (C)

TEM

PE

RAT

UR

E (°

C)

Average Wet Bulb = 12.6 C

Average Dry Bulb = 26.2 C

Dry Bulb (°C) Wet Bulb (°C)


Weather Data - Riyadh, KSA - Dry Bulb Variation by Hour


Weather Data - Riyadh, KSA - Wet Bulb Variation by Hour


Weather Data - Riyadh, KSA - Annual Load Profile

KEY CONCEPTS

- Air Conditioning moves Energy / Heat.

- Air Conditioning rejects heat through air-cooled or water-cooled systems.

- Weather and seasons impact energy use in these systems.

THE ENERGY WATER NEXUS SAVING ENERGY

REDUCES WATER CONSUMPTION


Definition: THE ENERGY WATER NEXUS

WATER FOR ENERGY

ENERGY FOR WATER

Energy and Water are Linked

Energy and power production requires water.

Water processing, production, distribution, and end use requires energy

Water-cooled district cooling plants also require water


THE ENERGY WATER NEXUS – Water Cost COMPONENTS OF WATER COST

Pre-Treat

Post-Treat

Dispose Acquire

Transport


THE ENERGY WATER NEXUS – Water Cost

WATER COST IS INCREASING • Population Growth

• Rising Standards of living – more water intensive

• Environmental pressures

• Infrastructure Costs

• Climate Change


THE ENERGY WATER NEXUS – Ways to Save Energy

SAVING ENERGY = SAVING WATER = SAVING MONEY

Avoidance Conserve Design Optimize Maintain • Insulation • Low-E Glass • Lighting

• Night setback • Isolate leaks • Lighting • CHW Reset

• District Energy • Highly Efficient and variable speed components, products and systems

• Central Plant and System Optimization

• Scheduled Service • Measurement and Verification plan


THE ENERGY WATER NEXUS – Ways to Save Water

SAVING ENERGY = SAVING WATER = SAVING MONEY

SAVE WATER : Reduce blow-down in the cooling tower Use well water, river water, sea water, effluent water

SAVE WATER : Use “waste heat” in a heat pump application

SAVE WATER : Collect and re-use cooling coil condensate

SAVE WATER : Use non-evaporative air-cooled heat rejection systems


Riyadh, KSA

RIYADH, KSA


Air-Cooled System vs Water-Cooled System - Riyadh, KSA

Assumptions - Energy Evaluated at SAR 0.26/kWh - Water Evaluated at SAR 4.00/m3

0.00

0.40

0.80

1.20

1.60

2.00

2.40

2.80

3.20

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

Air Cooled Water Cooled

Syst

em W

ater

Use

Gal

/Ton

-Hr

Chill

er P

lant

Sys

tem

Ene

rgy

kW/T

on

& O

pera

ting

Cost

SAR

/Ton

-Hr

Heat Rejection System Type

Annual Peak and Average Energy Use, Operating Costs, and Annual Average Water Use For Various System Types

Riyadh, KSA

Annual Average kW/Ton Annual Peak kW/Ton Operating Cost SAR/Ton-Hr Gal/Ton-Hr


Air-Cooled & Water-Cooled System Advantages

A-C RADIATOR SYSTEMS • No water consumption/ reduced chemical consumption

• Simplistic closed loop design

• Lowest maintenance

• Often Standard tubes and tube sheets

WATER-COOLED SYSTEMS • Lowest kW/ton

• Smaller footprint

• More supplier options

• Lower first cost


Summary Why do we need air conditioning? Allows building to be habitable. How does air conditioning work? Move unwanted heat from one area (building) to a location less objectionable. How does water play a role in air conditioning? Evaporation of water allows for energy and cost efficient heat rejection to the atmosphere. What roles do weather and climate play in air conditioning? Weather impacts both load and lift and thus energy consumption.


Summary Continued How can saving energy save water? Less energy equals less heat of rejection to the cooling tower. What can we do to save energy? Avoidance > Conserve > Design > Optimize > Maintain What are the two main choices in air conditioning heat rejection

systems? Air-cooled systems and water-cooled systems What is the Energy-Water Nexus? Energy Saves Water and Water saves energy! They are intrinsically

linked…


Air-Cooled System vs Water-Cooled System - Riyadh, KSA

Assumptions - Energy Evaluated at SAR 0.26/kWh - Water Evaluated at SAR 4.00/m3

0.00

0.40

0.80

1.20

1.60

2.00

2.40

2.80

3.20

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

Air Cooled Water Cooled

Syst

em W

ater

Use

Gal

/Ton

-Hr

Chill

er P

lant

Sys

tem

Ene

rgy

kW/T

on

& O

pera

ting

Cost

SAR

/Ton

-Hr

Heat Rejection System Type

Annual Peak and Average Energy Use, Operating Costs, and Annual Average Water Use For Various System Types

Riyadh, KSA

Annual Average kW/Ton Annual Peak kW/Ton Operating Cost SAR/Ton-Hr Gal/Ton-Hr

What other opportunities exist between

these two solutions?

Not enough energy

Not enough water


Next Session....Wednesday December 3, 2014


Questions and Answers - Please type in Q&A box lower right hand corner.

- Moderator will handle questions to presenter.

- Please complete the survey following the webinar

- Webinar will be recorded and available via download or streaming. Presentation slides will be available in pdf format at www.districtenergy.org

- If you are listening to the webinar recording and have questions, send them to [email protected]

- Register for the second webinar, held at the same time, Wednesday, December 3, 2014.


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