International Institute of Refrigeration
Ammonia and CO2 Refrigeration Technologies
International Conference
- Ohrid 2023 -

Keynote Speakers

Dr Andy Pearson Dr Andy Pearson, UK,
Star Refrigeration Ltd
President of Scientific Committee
Former President of IoR UK,
Member of IIR Commission E1
"Energy performance of process cooling equipment" 
Dr Predrag Hrnjak
Dr Armin Hafner, Norway,
University NTNU
"Smart CO2 refrigeration and heat pumping systems" 
Dr Andy Pearson
Sergio Girotto, Italy,
Enex Srl
"Optimal selection of system design and selection of
the best natural refrigerant for refrigeration
and HVAC systems"
Dr Predrag Hrnjak Sascha Hellmann, Germany,
Carrier Commercial Refrigeration
Fellow, R&D Project Leader
"Evolution of the CO2 refrigeration technology
from 2000, applications and an outlook
for the next several years" 
Dr Predrag Hrnjak
Svenn Ole Kjøller Hansen, Denmark,
Danish Technological Institute
Product Manager,
"Trends in heat pump technology in Denmark" 
Dr Predrag Hrnjak Special guest:

Bruce Nelson, USA,
Bruce V. Nelson Engineering, LLC
Former Chairman of IIAR
"IIAR Research related to
ammonia and CO2 systems" 

Main Topics of the Conference  
Design of modern ammonia (NH3) systems and technological innovation
Lowering of ammonia charge in the systems; Medium and small size ammonia systems;  
Advanced design; Factory-made units;
Compatibility of ammonia with metals and new oils.

Design of carbon dioxide (CO2) refrigeration and heat pump systems
Transcritical and subcritical operation;
Modifications of cycles to improve the energy efficiency;
Development of CO2 systems intended for hot climate;
Ejector as an expansion device.

New innovative components
Plate and “shell & plate” heat exchangers; DX evaporators;
Microchannel air-cooled condensers; Improved evaporative condensers;
Semi-hermetic and hermetic ammonia compressors;
High-pressure ammonia and CO2 compressors.

Energy efficiency of ammonia and CO2 refrigerating systems
Advantages of ammonia and CO2 versus fluorocarbon-based systems;
New secondary coolants; CO2 as a secondary coolant;
NH3/CO2 cascade systems.

Applications of ammonia and CO2 refrigeration
Cold stores, food and drink industries; Supermarkets; Air-conditioning systems (liquid chillers);
Heat pumps (medium and high temperature heating).

Absorption machines
Modified absorption cycles; Trigeneration and district cooling.

Ammonia and CO2 systems in developing countries
Modernisation, improvements, technical assistance, barriers.

Technical and safety issues; Guidelines and training materials
Regulations on the construction and operation of ammonia and CO2 refrigerating systems;
Education and training for: best practices, operating procedures, handling and safe operation.

Public awareness of the image and benefits of natural refrigerants
Crucial and sustainable contributions to a better environment; Barriers to market penetration;
Current and future use of natural refrigerants; Montreal Protocol and Kigali amendment, phase-down of HFCs.