36 Ammonia Technology and Its Applications Risto Ciconkov

AMMONIA TECHNOLOGY AND ITS APPLICATIONS

Prof. Dr. Risto Ciconkov, dipl. ing.Faculty of Mechanical Engineering,

University “Sv. Kiril & Metodij”Skopje, R. Macedonia

Delagate to IIR Member of

UNEP, ECA meeting, 2008

CONTENT

1. Introduction

2. Properties of Ammonia

3. Most common systems and applications

4. New technologies in ammonia systems - heat exchangers, - compressors,- new concept of systems.

5. Safety, prerequisites, facts

6. Event – Ammonia Refrigeration Technology 2009




1. Introduction

1834: Mechanical refrigerating system first time appeared. First refrigerants, natural: Ethyl-ether, CO2, NH3, ...

1930: CFCs (“freons”)

1987: Montreal Protocol, phase-out of CFCs

1990: HFCs introduction

1997: Kyoto Protocol, HFCs under control

Come back of natural refrigerants: NH3, CO2, HCs, water, air

Polemics; Confusion.





SHORT HISTORY OF REFRIGERANTS NaturalNH3CO2

HCs1834ethyl-ether(R610)

methyl-chlorideSO2

1930 CFCNH3 CO2

HC

1950HCFCCFCNH3

1990

HFC(CFC) HCFC

NH3

2008HFC

NH3 CO2HCs

Future

MontrealProtocol1987

KyotoProtocol1997



SHORT HISTORY OF REFRIGERANTS Natural

CO2

HCs1834ethyl-ether(R610)

methyl-chlorideSO2

1930 CFC

HC

1950HCFCCFC

1990

HFC(CFC) HCFC

2008HFC

NH3

NH3

NH3

NH3

NH3HCs

Future

MontrealProtocol1987

KyotoProtocol1997

CO2

CO2

2. PROPERTIES OF AMMONIA (NH3; R717)

NBP (Normal Boiling Point): -33.3 oC

Critical temperature: 132 oC

Latent heat: 1262 kJ/kg

ODP = 0 (Ozone Depletion Potential)GWP < 1 (Global Warming Potential)

Odour: characteristic, pungent

Explosion concentration limits: 15,5 - 28 % by volume

Detection threshold: 5 ppm

Ignition temperature: 650 oC

Tolerance limit: 500-1000 ppm



Advantages of ammoniaEnvironmental: ODP = 0, GWP < 1;

High values for energy efficiency;Excellent thermodynamic properties: - high critical temperature 132oC, - large latent heat,- large vapor density, - excellent for heat transfer. In vapor condition it is easier then the air;Easy detection (warning);Low price.

Disadvantages of ammonia:It is toxic;Flammable moderately in concentration in the air from 15,5 to 28%It is not compatible with copper.







Data: “Ammonia partnership”, A. Lindborg



Data: “Ammonia partnership”, A. Lindborg

0,00035 kg/m3L2R717

0,49 kg/m3L1R507

0,44 kg/m3L1R410A

0,31 kg/m3L1R407C

0,48 kg/m3L1R404A

0,25 kg/m3L1R134a

Practical limit according to EN 378

Refrigerant class



3. MOST COMMON SYSTEMS AND APPLICATIONS

Cold Storage

Food Processing

Drink processing: brewery

Dairy

Process Refrigeration: - pharmaceutical, - chemical, - petrochemical, - some special plants.

Industrial Heat Pumps

Air conditioning (new)



Cold Storage



Food Processing



Dairy



Brewery



Food processing

Chiller 4 kg NH3



Petrochemical plant



Air conditioning

Stutgard Airport



4. NEW TECHNOLOGIES IN AMMONIA SYSTEMS

Barrier: safety reason.

Decrease the charge (quantity) of ammonia in refrigerating systems.

- Avoid large reservoirs with liquid ammonia, - Avoid flooded shell-and-tube heat exchangers.

New technologies of heat exchangers.

- Technical standards and regulations; - Proper maintainance of the refrigerating systems;

- Avoid large pump systems.

New concepts of ammonia systems.

- Training of personnel.

Improvement of:

Plate evaporators

Ammonia and new technologies of heat exchangers

Flooded evaporators: gravity fed system, surge drum above; Dry expansion evaporator: miscible oil, electronic expansion valve;New technology: stainless steel welded modules, nickel brazed, fusion-bonded.



Microchannel heat exchangers

Air-cooled condensers Air cooler - evaporators⇒ Smaller heat exchanger size,⇒ Reduced refrigerant charges,⇒ Material: aluminium.






Shell-and-tube evaporators and condensers with steel enhanced tubes⇒ increase of efficiency.

Spray shell-and-tube evaporator (evaporating outside of tubes),Dry expansion evaporators, ⇒ reduced charge of ammonia.


Semi-hermetic ammonia compressor

Hermetic scroll compressor

Refrigerating capacity: 5 kW to 35 kW



Ammonia and new technologies of compressorsSystems with indirect cooling

C1

Tx1

Co1

displaycases

coldroom4 Co

4 Co

Ev1A

coolingtower

pump

NH3

secondaryloop (CO2)

New concepts of ammonia systems

Mixture, water + ethilen-glycol, water + propilen-glycol, water + NaCl; CaCl2New: potassium-acetate, CO2, ...



Systems with indirect coolingNew concepts of ammonia systems


Cascade refrigeration system

Tx2

C2

C1

Tx1

Co1

Ev /Co1 2

coldroom-20 Co

displaycases

-20 Co

coolingtower

high cascade (NH3)

low cascade(CO2)



New concepts of ammonia systems

Tx2

C2

C1

Tx1

Co1

Ev /Co1 2

displaycases

coldroom4 Co

coldroom-20 Co

displaycases

4 Co -20 Co

Ev1A

coolingtower

pump

high cascade (NH3)

low cascade(CO2)

secondaryloop (CO2)



New concepts of ammonia systemsCascade system and indirect cooling

SUPERMARKETCascade system and indirect cooling



Compact constructions, fully sealed and tested in factory



New concepts of ammonia systemsCost comparison: HFC chiller vs NH3 chiller



Assumptions, Energy cost: 8 eurocent/kWh; Operation: 365 days/year

Source: Sabroe (Denmark)years



5. Safety, prerequisites, facts Ammonia refrigerating systems - SAFETY



Technical standards and regulations.

Proper maintainance of the refrigerating systems. Training of personnel.

Prerequisite:



Proper maintainance.Training of personnel.

Ammonia refrigerating systems in developing countries Ammonia refrigerating systems in developing countries



Proper maintainance.Training of personnel.

Proper information based on facts are necessary.



The concentration of 5 ppm is smelled and it worries the people.

Ammonia is one of the most “honest“ chemicals, warning of its presencebefore it becomes dangerous.

FACTS FOR AMMONIA SYSTEMS

Ammonia is excellent refrigerant which is in use in the past 150 years.

The future of ammonia refrigerant has never been more prospective than today.

The ammonia technology is old?! Today there are modern better systems with HFC refrigerants?!



International Institute of Refrigeration

Faculty of MechanicalEngineering, Skopje

3rd International Conference

NH3

NH3

NH3 NH3

NH3NH3

NH3

NH3

NH3

NH3NH3

NH3

Ammonia Refrigeration Technology

7-9 May 2009, Ohrid, Macedoniawww.mf.edu.mk



Ammonia Refrigeration Technology April 2007, Ohrid, Macedonia



International Institute of Refrigeration

Faculty of MechanicalEngineering, Skopje

NH3

NH3

NH3 NH3

NH3NH3

NH3

NH3

NH3

NH3NH3

NH3

Ammonia Refrigeration Technology

7-9 May 2009, Ohrid, Macedoniawww.mf.edu.mk

Thank you.

3rd International Conference

36 Ammonia Technology and Its Applications Risto Ciconkov

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