Refrigeration & A/C Technology 8th Edition _ Unit 09 (Oil Chemistry and Management)
24. Explain what is meant by a non-pressurized recovery container, and briefly explain which applications it is used for.
A non pressurize recovery container is a recovery cylinder that must be clean, empty and in a vacuum of about 1000 microns before recovery is started.
26. What is a quick-couple or quick-connect and where are they used?
A quick Couple or quick Connect is a valve located at the end of a hose that hold the refrigerant in the hose when disconnected to help reduce refrigerant loss.
14. Describe the difference between an azeotropic refrigerant blend and a near-azeotropic or zeotropic refrigerant blend.
Azeotropes are a blended refrigerants of two or more mixtures. When mixed together they behave like R12 or R22 when phase changing from a liquid to a vapor. Only one boiling point or one condensing point exists for each given system pressure.Near- Azeotropic / zeo tropic (to a greater extent) experience a temperature glide. Temperature glide occurs when a mixture has many temperatures when it evaporates or condenses at a given pressure.
12. CFCs are more harmful to the stratospheric ozone layer than HCFCs because they contain _________.
CFC's have no hydrogen which makes them a stable compound when compared to HCFC which have hydrogen an chlorine. Hydrogen is unstable and tends to break down faster.
11. Describe the differences between CFCs, HCFCs, HFCs, and HCs.
CFCs contain chlorine , have longer lives, greatly deplete the ozone layer, and are more stable. HCFCs contain chlorine, have shorter lives, deplete the ozone layer much less than CFCs and are less stable than CFCs. HFCs contain no chlorine and do not deplete the ozone layer. Hcs have no chlorine and do not deplete the ozone layer. HCs are flammable. All are global warming chemicals.
25. What is the name of the federal agency that must approve containers into which refrigerant may be transferred?
Department of transportation
9. Describe the difference between a direct and an indirect global warming potential.
Direct global warming is the effect cause by a refrigerant leaking to the environment which gets caught in the lower atmosphere and causes a greenhouse effect where as indirect global warming is cause by the refrigerant leak causing longer system run time which needs more electrical power to run, and el. Power is made from fossil fuels and other substances that also contribute to global warming
18. What agency of the federal government is charged with implementing the United States Clean Air Act Amendments of 1990?
EPA
13. True or False: HFCs do not damage the ozone layer but still contribute to global warming.
False
6. True or False: Only CFCs and HCFCs contribute to global warming
False
7. Explain what a global warming potential (GWP) is.
GWP's are given to refrigerant that cause a direct effect of global warming, chemicals that are emitted directly into the atmosphere. Direct effects of global warming are measured by comparing them to CO2, which has an GWP of 1
5. An increase in the natural greenhouse effect that leads to heating of the earth is called _________.
Global Warming
2. Describe the difference between good and bad ozone.
Good Ozone like the stratosphere protects the earth from harmful ultraviolet rays from the sun, Bad Ozone, Like the Troposphere is considered unwanted ozone because it is a pollutant .
4. Which refrigerants have a 0 ODP?
HFC's and HC's have an ozone depletion Potential of 0
3. Explain the process of ozone depletion resulting from the breaking up of a CFC molecule in the stratosphere.
Once a CFC molecule is in the stratosphere , Ultraviolet radiation will break off a chlorine atom (Cl) from the CFC or HCFC molecule. The chlorine atom can destroy up to 100,000 ozone molecules. The depletion of Ozone lets more UV-B radiation reach the earth witch causes an increase in skin cancer and an increase in the frequency of cataracts in humans and animals, a weakening in the human immune system and a decrease in plant and marina life.
1. What is the difference between the oxygen we breathe and the ozone located in the earth's stratosphere?
Ozone is a form of oxygen, with each molecule consisting of three atoms of oxygen O3 , The oxygen we breath contains two atoms, O2
19. Explain the differences between active and passive recovery methods.
Passive recovery, is when the technician uses the internal pressures of the system or the system compressor to aid in that recovery process Active recovery , s when a recovery machine is used.
15. Why are there more safety precautions for R-410A than with other popular refrigerants like R-22 and R-404A?
R-404A systems operate at much higher pressures (60 % higher ) in air- conditioning applications than a conventional R-22 system. Gauge manifold sets, hoses, recovery equipment, and recovery storage cylinders all have to be designed to handle the higher pressures of R-410A . Different gauge line connections are used for the two refrigerants, preventing the technician from making a mistake. In fact, the gauge and manifold set for R-410A is required to range up to 800 psig on the high side and 250 psig on the low side, with a 550 psig low side retard. All R- 410A hoses must have a service rating of 800 psig. Even filter driers for R- 410A must be rated and capable of handling the higher pressures.
17. What is the name of the conference that was held in Canada in 1987 to attempt to solve the problem of refrigerants released into the atmosphere?
The Montreal Protocol
8. Describe the differences between global warming and ozone depletion
The difference between an ODP and GWP is: Not every refrigerant has an ODP, The ODP is a number given to a refrigerant that says how strong a refrigerant causes ozone depletion in the stratosphere, whereas all refrigerant have a GWP, CFC HCFC and HFC as well as CO2 water vapor and may other chemicals absorb reflect and refract the earths infrared radiation and prevent it from escaping the lower atmosphere.
27. The standard that a refrigerant must meet after it has been reclaimed and before it can be sold to another owner is
The standard that a refrigerant must meet after it has been reclaimed and can be sold to another customer is ARI 700
16. The three most popular synthetic oils in the refrigeration and air-conditioning industry are _________, _________, and _________.
The three most popular synthetic oils are Polyol ester (POE) Mineral oils and Polyalkylene glycol (PAG) OILs
10. What measurement or index takes into consideration both the indirect and direct global warming effects of refrigerants?
The total equivalent warming impact (TEWI) takes into consideration both the direct and indirect global warming effects of refrigerants.
20. Are federal excise taxes on reclaimed refrigerants the same as those for new refrigerants?
There is no tax on reclaimed refrigerants, like there are federal takes on new refrigerants.
21. To recover refrigerant means to _________.
To Recover means to remove refrigerant in any condition from a system and store it in an external container without necessarily testing it or processing it in any way.
22. To recycle refrigerant means to _________.
To Recycle means to clean the refrigerant by oil separation, and single or multiple passes through devices such as replaceable core filter driers witch reduce moisture, acidity and particulate matter.
23. To reclaim refrigerant means to _________.
To reclaim means to process refrigerant to new product specifications by means which may include distillation. It will require chemical analyze of the refrigerant to determine that appropriate product specifications are met. This term usually implies the use of process or procedures available only at a reprocessing or manufacturing facility.
28. Briefly describe the two types of piercing valves used in the industry, and list some advantages and disadvantages of both.
Two types of piercing valves are a gasket type and a solder on type. The gasket type can be use to quickly pierce a pipe but they should be removed when the service is done because the gasket can leak over time. The solder type is permanently soldered into the system. Disadvantage, the system must be emptied to applies this, Advantage, No leaks when its applied and will not have to be removed.
