Annex 18 - Thermophysical Properties of Environmentally Acceptable Refrigerants

 

Introduction
The phasing out of CFCs and HCFCs has led to a global quest to find alternative refrigerants for heat pumping equipment. Therefore the IEA Heat Pump Programme started this project - Annex 18 - entitled: Thermo Physical Properties of Environmentally Acceptable Refrigerants, and was an international study of refrigerant properties. The project made an important contribution by carrying out an international study into the thermo physical properties of the leading contenders.

The information generated is used by a broad spectrum of scientists and engineers working on heat pump, air-conditioning and refrigeration equipment. Annex 18 has also helped advance refrigerant understanding by bringing together properties experts in a spirit of international cooperation.

• Start date: December 1989
• End date: 1999

Objectives

• To provide a reliable source of information on refrigerant properties
• To determine internationally accepted analysis tools, such as equations of state
• To enable better equipment design using environmentally acceptable refrigerants

Project manager and participating countries
The project manager (the so-called Operating Agent) was the National Institute of Standards Technology (NIST), on behalf of the USA.
The following countries participated in this project: Austria (Phase 1 only), Canada, Germany (Phase I and II only), Japan (Cooperating Agent for Phase 2), Norway, Sweden, UK and USA.

 

Activities
In this project three phases were discerned:

 

Activities - Phase 1
Phase 1 focused on the refrigerants HFC-134a and HCFC-123 (replacement refrigerants for the widely used CFC-12 and CFC-11). Tasks included:

• Surveying current research

• Compiling data

• Evaluating equations of state

• Preparing properties bulletins for HFC-134a and HCFC-123

• Phase I led to definitions of international standards for the properties of HFC-134a and HCFC-123, a sanction endorsed by the International Institute of Refrigeration.

Activities - Phase 2
Phase 2 focused on alternatives to HCFC-22, including HFCs and the so-called `natural' refrigerants such as ammonia. Particular attention was paid to the thermo physical properties of mixtures. Phase 2 was completed in March 1996 and included the following tasks:

• Studying mixing rules

• Establishing a reference mixture

• Agreement on a dataset for evaluating mixture equations of state

• Recommending various mixture models

• Assessing the properties of ammonia.

Activities - Phase 3
A third phase was then added, which was completed in December 1999 and concentrated on HFC mixtures, ammonia and hydrocarbons. Annex 18 also cooperated with Annex 22 (Compression Systems with Natural Working Fluids) during their study of thermo physical properties of natural refrigerants.

 

Publications
The project resulted in the following publications:

The reduced price will be charged for countries participating in the project and Heat Pump Programme member countries. Click here for a list of the HPP member countries ›››.

• An Assessment of the Current Status of the Thermo Physical Properties of Ammonia
  Order No. HPP-AN18-1; 62 pages; Report from 1994. Republished by the HPC in April 1995. Full price € 45 and reduced price € 15.
  This report summarises and analyses experimental data, and compares this with existing equations of state and correlations.
  

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• Comparison of Equations of State for HCFC-123
  Order No. HPP-AN18-2; 45 pages; Report from 1993. Republished by the HPC in April 1995. Full price € 45 and reduced price € 15.
  Presents three equations of state and makes recommendations based on rigorous comparison with experimental data.
  

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• Comparison of Equations of State with Experimental Data for R134a and R123
  Order No. HPP-AN18-3; 45 pages; Report from 1993. Republished by the HPC in April 1995. Full price € 45 and reduced price € 15.
  Includes ideal gas and fixed points, and compares the saturation and single-phase properties.
  

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• Comparisons of Equations of State with Experimental Data for R-32 and R-125
  Order No. HPP-AN18-4; 84 pages; Published March 1997. Full price € 45 and reduced price € 15.
  This Annex 18 report presents the results of the study comparing equations of state with experimental data for R-32 and R-125.
  

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• Evaluation of Thermodynamic Property Models for Mixtures of R-32, R-125 and R-134a
  Order No. HPP-AN18-5. Published 1998. Full price € 45 and reduced price € 15.
  This Annex 18 final report presents the results of evaluating thermodynamic property models for different mixtures of R-32, R-125 and R-134a.
  

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Last updated: 1 March 2004

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