COLD WEATHER TECHNOLOGIES :

REVOLUTIONARY GREEN HEAT

Who is Cold Weather Technologies (CWT)?

CWT is the division of Grit responsible for the Heat Driven Loop technology

What is the Heat Driven Loop?

The Heat Driven Loop

• A new adaptation of existing thermosyphon heat pump technology

• Uses latent heat of evaporation from an evacuated, closed system to transfer heat

• Consists of an evaporator section and

a condenser/heat exchanger section.

Natural gas line heaters

Used in upstream, transportation, and distribution systems

Used to stop internal and external freezing on lines and/or equipment

Joule-Thomson Effect

Why does ice form on the lines downstream of the regulator?

Because of the Joule-Thomson Effect:A gas will lower its temperature as the pressure is decreased.

This effect is also called the Joule-Kelvin Effect and is the basis of how modern refrigeration techniques work.

What are the advantages of CWT?

• Increased heat transfer efficiency so reduced fuel requirements• Lower fuel pressure at burner• Eliminates direct firing of firetubes – no scale – no hot spots• Reduced hazards• Reduced environmental risk and emissions• Lower heat losses to ambient• Increased thermal efficiencies – in the order of 80%• Reduced fuel requirements – annual reductions in excess of

50%• Ease of operation and dependability• Reduced maintenance • Safe to light and silent• Reduced glycol requirements

Energy required for phase change chart

Lower boiling point

Mount Everest 29,000 ftWater boils at 68°C

Sea Level 0 ftWater boils at 100°C

CWT Line HeaterWater boils at 43°C

Deep SpaceWater boils at 39°C

Operating Parameters

PressureOperates on a vacuum As low as -26” Hg when coldMaximum operating pressure is 14.7 psig

TemperatureOperates below 121°C

Other good things about the vacuum…

Minimal air in system reduces corrosionLower operating temperature reduces heat loss to ambient

Alignment and support guides

High Pressure – 6 pass Process Coil

Alignment / Support Guides

Inside the steam condenser chamber

Inside the Steam Condenser Chamber

Alignment and Support Ports

Steam Inlet

Condensate Outlet

The new heat exchanger

Testing new exchangerINLE

T

OUTLET

The new style heat exchanger in a 2.3 million BTU heater is much smaller than the old style.

Some history

• Process was first developed when trying to find a better way to heat oilfield tanks with low pressure gas

• SaskEnergy suggested looking at developing a line heater• Initial bench testing done in Lloydminster under the direction of the

SRC in 2003

Bench test results

“The HDL Dry Unit technology shows significant advantage over conventional line heaters including:

• improved overall efficiency

• improved combustion efficiency

• Reduced emissions

• Improved response time with a lower thermal capacitance”

Saskatchewan Research Council

Line heater field trials

Sask Energy field tested 2 units

• Maidstone – 250,000 BTU/hr

• Melville – 500,000 BTU/hrInstalled in fall of 2003

Trouble free operationInspected after 6 and 15 months

- no corrosion or erosion - no breakdown in glycol

qualityDissected Maidstone in May 07

- no concerns

CWT SaskEnergy performance

Melville TBS• 315,000 btu/hr

• In service: 4 years

• Annual Savings: 42%( $3,000/yr )

CWT SaskEnergy performance

Yorkton TBS• 770,000 btu/hr

• In service: 1 year

• Annual Savings: 31%( $5,000/yr )

CWT SaskEnergy performance

Battleford TBS• 770,000 btu/hr

• In service: 2 years

• Annual Savings: 60%( $16,000/yr )

Melville station usage ratio

Melville Station Usage Ratio Line Heater Consumption (scf) per Station Throughput (mcf)

0.00

0.50

1.00

1.50

2.00

2.50

3.00O

ct-0

2

Nov

-02

Dec

-02

Jan-

03

Feb

-03

Mar

-03

Apr

-03

May

-03

Jun-

03

Jul-0

3

Aug

-03

Sep

-03

Oct

-03

Nov

-03

Dec

-03

Jan-

04

Feb

-04

Mar

-04

Apr

-04

May

-04

Jun-

04

Jul-0

4

Aug

-04

Sep

-04

Oct

-04

Nov

-04

Dec

-04

Jan-

05

Feb

-05

Mar

-05

Apr

-05

May

-05

Jun-

05

Jul-0

5

Aug

-05

Sep

-05

scf

Bu

rned

per

msc

f T

hro

ug

hp

ut

Conventional Heater

Cold Weather Technologies Heater

Conventional Heater

Cold Weather Technologies Heater

Melville station consumption per day

Melville StationConsumption per Heating Degree Day

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00O

ct-0

2

Nov

-02

Dec

-02

Jan-

03

Feb

-03

Mar

-03

Apr

-03

May

-03

Jun-

03

Jul-0

3

Aug

-03

Sep

-03

Oct

-03

Nov

-03

Dec

-03

Jan-

04

Feb

-04

Mar

-04

Apr

-04

May

-04

Jun-

04

Jul-0

4

Aug

-04

Sep

-04

Oct

-04

Nov

-04

Dec

-04

Jan-

05

Feb

-05

Mar

-05

Apr

-05

May

-05

Jun-

05

Jul-0

5

Aug

-05

Sep

-05

scf

per

HD

D

Melville station consumption per month

Melville Station Consumption

0

20

40

60

80

100

120

140

160

180

Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug

mcf

/mo

nth

Conventional CWT Year 1 CWT Year 2

Numbers…

• The CWT line heater has a thermal efficiency of between 75 and 80%. • A conventional line heater has a thermal efficiency of 35 to 45%. • In most applications the CWT will use less than half the fuel for the

same load as a conventional heater.• A 500,000 btu/hr CWT heater will do the work of 1.0 mmbtu/hr

conventional heater – a lower capital cost. • If we assume that both are running 50% of the time, the conventional

heater would consume 2,190 mmbtu/year more than the CWT. • Using a gas price of $7.00 per mmbtu, the extra fuel cost is in the order

of $15,330 annually.

Glycol

• CWT Dryline Heaters are shipped with all the required fluid – there in no glycol to buy

• The CWT is a sealed unit – no need to “top up”• A small amount of glycol so no containment is required• A 1.0 mmbtu/hr conventional heater requires about 25 bbls of

glycol (@ $700/bbl = $17,500)• Glycol is propylene based – minimal or no containment

required

GHG emissions

• A single conventional bath-type line heater burning 500,000 btu/hr NG emits over 520 t of CO2 e in one year

• Using the 53% reduction in consumption determined by SaskEnergy that same line heater consumes 235,000 btu/hr and emits 244 t of CO2 e in one year

• This results in a GHG reduction of 276 t of CO2 annually on the basis of reduced fuel consumption

Melville emissions

Melville Emissions

0

20000

40000

60000

80000

100000

120000

140000

Conventional (Year 0) CWT Year 1 CWT Year 2

An

nu

al lb

s C

O2e

40% reduction

from conventionalline heater

50% reduction

from conventionalline heater

Some of our clients

• Aliant Energy• ATCO Pipeline• ATCO Gas• Barchard Engineering• Campbell Ryder

Engineering Ltd.• Enbridge• ENGAS• Heritage Gas• Keyspan

• National Fuel Gas Supply Corp.• National Grid• Nicor• Pacific Northern Gas• Puget Sound Energy• Sask Energy• SNC Lavalin• Terasen Gas• Union Gas• Numerous Canadian gas co-ops

The Cold Weather models images

The Cold Weather models

Model 140 Evaporator

Model 315

Model 315 Evaporator

Model 385 Evaporator

Model 630

Model 630 Evaporator

Model 630E

Model 630E Evaporator

Model 770 Evaporator(2x385’s)

• Modular design for large heaters

• Multiple Evaporators on Single Condenser

• Staged Firing• Uses Internal or Utility

Power

Model 770 Evaporator

Model 770

Model 770 Evaporator

Process Gas Temp Sensors

Process Gas Temp Sensors

Alliant, Iowa

Alliant, Iowa

Keyspan, Canarsie

Keyspan, Canarsie

Keyspan, Canarsie

Keyspan, Canarsie

CWT 770 Modular2.3 MM btu/hr at Saskatoon TBS #2

CWT 770 Modular Evaporator

2.3 MMBTU for Enbridge2.3 Million BTU Evaporator

3 Million BTU in shop

3 Million BTU Evaporator

Operating the Line Heater“The Basics”

Pressure when the heater is cold

When the heater is cold the pressure should be in the order of -24” Hg.

Fluid level

The line heater contains a mixture of glycol and water. The volume is dependent on the style of evaporator but is generally around 20 gallons.

When cold the site glass should be near full.

When operating the level varies dramatically but should stay in or near the middle of the site glass

Installing the unit

A solid foundation is required (cannot slope away from condensate return),Conduit to the gas process line downstream of the station is required.

Poor footing image

Thermopile power system

Pressure gauges

Evaporator Boiling at 77°C and -19” Hg (-9.6 psig)

When operating normally in Natural Gas Line Heating applications the device will generally run at some level of negative pressure.

Discharge temperature switch

This switch controls the vapor temperature and is generally set between 79 and 93°C.This acts as a thermostat and will open and close the main gas valve as required

High pressure switch

This pressure switch will shutdown the main burner when the pressure reaches a preset limit (usually set to shut down at about 3-5 psig). This may be manual or automatic reset

High temperature ESD switch

This temperature control is located in the control box. This is the high temperature ESD which will trigger if the glycol mixture reaches 115° F in the liquid phase. This ESD has a manual reset.

Rupture disk

This is a rupture disk which will fail at 15 psig. If for some reason the heater pressure exceeds 15 psig the disk will burst and the water/glycol mixture would be vented and collected in the containment

Containment vessel image

Evaporator model containment shown. Boiler model containment is slightly different.

Process Temperature or line temperature is controlled by this thermostat.

This is generally installed at the outlet from the station, downstream of the regulation.

This controls the temperature of the gas after the regulating station.

This is set by the operator (usually around 3°C)

Line temperature thermostat

Why a CWT Dry Line Heater?

On new systems or replacements the reasons are the same…

• Low capital cost• Fuel economy• Less glycol• Less maintenance• Simple• Safe• Silent