HVAC Refrigerant Properties
Objectives • After completing the material in this chapter, the student should be able to: • List the desired properties for refrigerants. • Explain the characteristics of hydrocarbons. • Explain how a refrigerant becomes halogenated. • Explain the chemical elements that make up CFC, HC, HCFC, and HFC refrigerants. • Differentiate between azeotropic, near-azeotropic, and zeotropic refrigerant blends. • Explain how ozone protects the Earth. • Explain the difference between good and bad ozone.
Objectives • After completing the material in this chapter, the student should be able to: • Explain how ozone is destroyed. • Explain the concept of global warming. • Interpret ozone depletion potentials (ODP) and global warming potentials (GWP). • Determine the proper oil to use with various types of refrigerant. • Differentiate between reusable and disposable refrigerant cylinders. • Obey laws regarding certification and refrigerant handling.
Objectives • After completing the material in this chapter, the student should be able to: • Differentiate between Type I, Type II, Type III, and Universal certification. • Differentiate between refrigerant recovering, recycling, and reclaiming. • Demonstrate passive and active recovery methods. • Demonstrate methods to recycle refrigerant.
Refrigerant Types • Environmentally friendly • Non-toxic • Non-flammable • Chemically stable • Recyclable • Relative low cost • Detectable at low concentrations
Ethane and Methane • Most refrigerants in use today originate from one of these two base molecules. • Methane and ethane are referred to as pure hydrocarbons. • Pure hydrocarbons contain only hydrogen and carbon. • Other hydrocarbons include propane and butane.
Ethane and Methane • (A) Methane molecule (B) Ethane molecule
Classes of Refrigerants in Use Today • Hydrocarbons (HC) • Hydrofluorocarbons (HFC) • Chlorofluorocarbons (CFC) • Hydrochlorofluorocarbons (HCFC)
Ozone Depletion • Skin cancer. • Eye-related issues, including cataracts. • Decreased plant growth rates. • Compromised immune systems.
Atmospheric regions Ozone Depletion
Global Warming • Also referred to as the greenhouse effect. • Earth’s inability to release heat by radiation back to the atmosphere.
Ozone Depletion Potential (ODP) • CFC refrigerants have high ozone depletion potentials. • HCFC refrigerants have lower ozone depletion potentials. • HFC and HC refrigerants have an ozone depletion potential of zero.
Global Warming Potential (GWP) • CFC refrigerants have high global warming potentials. • HCFC refrigerants have lower global warming potentials. • HC refrigerants have low global warming potentials. • HFC refrigerants have very low global warming potentials.
Refrigerant Oils • Alkylbenzenes • Glycols • Esters
A list of refrigerants with their appropriate oils. Refrigerant Oils
Refrigerant Cylinders • Disposable refrigerant cylinders • Reusable refrigerant cylinders • Recovery cylinders
Refrigerant Cylinders • Disposable refrigerant cylinder
Refrigerant Cylinders • Reusable refrigerant cylinders.
Refrigerant Handling • Always be thoroughly familiar with surroundings. • Wear personal protection equipment (PPE) including safety glasses, gloves, and protective clothing. • Recovered refrigerant may be acidic. BE CAREFUL. • Do not inhale refrigerant vapors.
Refrigerant Handling • When possible, work in well-ventilated areas. • Refrigerant containers should never be filled to more than 80% capacity. • Always secure cylinders before transporting. • Properly label all refrigerant cylinders.
Refrigerant Handling • Store tanks in a cool, dry place. • Always maintain equipment and tools including recovery equipment, gauges, hoses, and refrigerant cylinders. • Dedicate hoses for use with specific refrigerants to reduce cross-contamination. • Change oil and filters regularly on recovery equipment.
EPA Type 608 Certification • Type I – Small Appliances • Type II – High-Pressure and Very-High- Pressure Appliances • Type III – Low-Pressure Appliances • Universal – Type I, Type II, and Type III
Refrigerant Recovery • Passive recovery: • Uses the system compressor to pump the refrigerant from the system to an approved DOT refrigerant cylinder • Active recovery: • When the system contains more than 15 pounds of refrigerant or if the system compressor is inoperative
Refrigerant Recovery • Setup for passive refrigerant activity.
Active recovery setup with moisture indicator and filter installed. Recovered Refrigerant Identification
Summary • Refrigerants should be environmentally safe, non-toxic, non-flammable, and chemically stable. • Halogen refrigerants are created when some hydrogen atoms are replaced with chlorine or fluorine atoms. • Hydrocarbons (HC) contain only hydrogen and carbon. • Hydrofluorocarbons (HFC) contain only hydrogen, fluorine, and carbon. • Chlorofluorocarbons (CFC) contain only chlorine, fluorine, and carbon.
Summary • Hydrochlorofluorocarbons (HCFC) contain only hydrogen, chlorine, fluorine, and carbon. • Blended refrigerants are mixtures of two or more other refrigerants and can be azeotropic, near-azeotropic, or zeotropic. • Stratospheric ozone protects the Earth from ultraviolet radiation. • Ozone molecules are destroyed by chlorine. • Chemical substances are rated by their ozone depletion potentials (ODP) and their global warming potentials (GWP).
Summary • CFCs have high ODPs, while HFCs and HCs have low ODPs. • Synthetic oils can be alkylbenzenes, glycols, and esters. • Refrigerant cylinders are color-coded and can be reusable or disposable. • The Montreal Protocol Act paved the way for a number of regulations regarding refrigerant handling. • Technicians must be certified as per EPA Section 608 guidelines.
Summary • Refrigerant can be recovered, recycled, or reclaimed. • Recovery involves the removal and storage of the refrigerant. • Recycling involves the filtering of refrigerant prior to reintroducing it to the system. • Reclaiming involves restoring the refrigerant to ARI 700 standards.