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Development of climate friendlier truck refrigeration systems with R290

in South Africa

Transport Refrigeration in South Africa

Side Event MOP Dubai 2015

Bill Wilson, Transfrig

Dr Daniel Colbourne, HEAT/GIZ

Michael Schuster, GIZ South Africa

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Contents

• The project

• Safety aspects and risk assessment

• COP improvements

• Emission savings – Life cycle comparison

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- the cooperation partner

• Only South African transport refrigeration company

• Founded in 1980

• Local production in Johannesburg

• High market share for trucks and vans in South Africa

• Sales in Sub-Saharan countries

and internationally

• leader for environmental friendly

transport refrigeration technology

in Africa

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Technical description

MT450 MT480

Refrigerant R-404a HC-290

Cooling capacity 7.95 kW for 0°C

4.55 kW for -20°C

7.95 kW for 0°C

4.55 kW for -20°C

Powered by Open-type, driven by diesel

engine

Semi-hermetic compressor,

electrically driven, diesel-driven

alternator

Expansion device Thermostatic expansion valve Electronic expansion valve

Compressor Fixed speed Variable speed (60 – 100%)

Condenser tubing 9.5 mm 5 mm

Evaporator tubing 9.5 mm 7 mm

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Circuit Arrangement of the new MT480

Condenser

Compressor

Condensing unit

Truck

EEV

Evaporator

Combined suction

Accumulator / liquid receiver

HGD valve

Non-return Valve

HP LP

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Contents

• The project

• Safety aspects and risk assessment

• COP improvements

• Emission savings – Life cycle comparison

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Safety risks using

flammable

refrigerants Flammable

concentrations

Leakages

Accumulation

Size of potential leaked amount

Sources of ignition

Components

Hot surfaces

Open flames

Improper handling

Servicing

Storage and transport

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First considerations to address safety risks

• Charge size reduction to 20% of R-404A charge

• Extensive training of servicing personnel

• Leak reduction

o Components comply with EN 16084 (Tightness of components and joints) and ISO

14903 (Tightness of controls)

o Protection against ice damage

o Eliminate vibrations

o Strong steel housing protects against damage

o Entire circuit is brazed

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Leak simulation tests

Electrical panel

Truck air intake

Air intake and starter motor

Truck engine

gap

External light switch

Smoker at door

Evaporator inlet

Floor below evaporator

Beneath door

Inside, centre, high

Inside, centre, low

Test conditions (examples)

• Leak sizes

• Leak positions

• Operating conditions

• Empty/fully loaded

• Air-flow / no air-flow

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Results (example): Leak of R290 into the refrigerated space, subsequent

door opening

Evaporator fan off Evaporator fan on

Door opening

Amount of leaked gas = 1 kg (>150% of charge size 0.65kg) the in order to cover possible overcharging

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Eliminate Sources of Ignition (Example 1)

Electrical panel

• Cover

• Fully sealed against refrigerant

• Secondary barrier to the rear of the

enclosure

• Explosion proof cable glands

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Eliminate Sources of Ignition (Example 2)

Diesel engine starter motor

• Sparking contacts in casing with air

gaps positioned within the condensing

unit

pre-purge system operates condenser

fan for some times. This decreases a

possible refrigerant accumulation to

below the lower flammability limit

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Compliance with safety standards The conformity to the following standards was tested and ascertained:

1. EN 378-1:2008+A2:2012, Part 1: Basic requirements, definitions, classification and selection criteria

2. EN 378-2:2008+A1:2009+A2:2012, Part 2: Design, construction, testing, marking and documentation

3. EN 378-3:2008+A1:2012, Part 3: Installation site and personal protection

4. EN 378-4:2008+A1:2012, Part 4: Operation, maintenance, repair and recovery

5. Explosive Atmosphere Directive (ATEX); 94/9/EC

6. EN 16084: Refrigeration systems and heat pumps: Tightness of components and joints

7. EN 60079-10-1: Explosive atmospheres. Classification of areas

8. EN 1127-1: 2011 Explosive atmospheres — Explosion prevention and protection Part 1: Basic

concepts and methodology

Note: although ATEX and EN 1127-1 are not directly applicable to non-static

applications, the measures are still considered applicable

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Leak identification system

Gas detector

• Immediate detection of leak

• Unreliable in the long-term

• Regular calibration and checking

needed

• Easily damaged

• Adds substantial costs

Automatic shut-down based on system

operating parameters

• e.g. suction pressure & temperature,

superheat, degree of EEV opening

• Longer response time than gas detector

• More reliable in the long-term, no

calibration needed

• No contamination

• Extensive testing necessary

Chosen because of low cost, better

reliability, not dependent upon special

maintenance over lifetime

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Safety concept – reduce risk of flammable refrigerant

1. Reduce charge size

2. Reduce leakages by using semi-hermetic design and tight components

3. Determine possible areas of high refrigerant concentrations after leak

4. Remove sources of ignition

5. Install automatic shut-off in case of (catastrophic) leakage

6. Train personnel in the safe use of hydrocarbon refrigerants

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Contents

• The project

• Safety aspects and risk assessment

• COP improvements

• Emission savings – Life cycle comparison

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Improvement of energy efficiency

Measure Efficiency benefits

HC-290 refrigerant

Reduced condenser tubes

Reduced evaporator tubes

Redesign of evaporator and condenser

Liquid suction heat exchanger

Electronic expansion valve

Variable speed compressor

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Performance improvements due to use of R-290 at high ambient temperatures

(fixed speed compressor)

Performance at extreme conditions for MT (T = 0°C) Performance at extreme conditions for LT (T = -20°C)

COP up to

28% higher COP up to

27% higher

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Higher cooling capacity at high ambient temperatures

Cooling capacity at extreme conditions for MT (T = 0°C) Cooling capacity at extreme conditions for LT (T = -20°C)

Higher capacity

at high ambient

temperatures

Higher capacity

at high ambient

temperatures

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Contents

• The project

• Safety aspects and risk assessment

• COP improvements

• Emission savings – Life cycle comparison

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Life cycle emissions – comparison R-404a and HC-290

R-404a unit HC-290 unit

GWP 3,922 3

Charge size 3.5 kg 0.65 kg

Annual

leakage rate

50 % <<50 %

Direct

emissions

6.9 t CO2 eq 0.001 t CO2 eq

Fuel

consumption*

1.2 L/h 1.0 L/h

Runtime hours 1,500 h/year 1,500 h/year

Indirect

emissions

4.8 t CO2 eq 4.0 t CO2 eq

Total

emissions

11.8 t CO2 eq

4.0 t CO2 eq

* estimate

0

5

10

15

R-404a HC-290

Em

issio

ns [t C

O2 e

q]

Indirect emissions Direct emissions

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Summary

Environmentally friendly refrigerant

High energy efficiency (also for high ambient temperatures)

Reduced refrigerant leakage

Comprehensive safety concept for flammable refrigerants

Compliance with safety standards