Its All Greek to Me!

Years ago a proper education included the study of Greek. Why? Because so much of our modern language and western culture is rooted in Greek culture. As education has moved away from studying classics and Greek, we have retained many symbols and phrases without really understanding them. Even in HVACR, we use Greek symbols on a regular basis. Ever hear someone refer to taking a “Delta T” measurement? This simply means to measure the temperature difference, or change in temperature. Delta comes from the uppercase of the fourth letter of the Greek alphabet, which looks something like a triangle, Δ. In many math and science fields, Δ is used as shorthand for change, or difference. One way to think about this is to look at the form of the letter Δ. It changes in width from the top to the bottom. An easy way to remember it is simply that Delta starts with “D” and Difference starts with “D.” So Delta T simply means temperature difference. It just sounds so much more educated to be checking out a system’s Δ T. Two more commonly used terms which come from Greek are: zeotrope and azeotrope. Zeo means to boil, Tropos means to turn; thus, a refrigerant which is zeotropic turns, or changes as it boils. “A” used as a prefix means “not.” For example, amoral means not moral. Similarly, azeotrope means a refrigerant that does NOT change when it boils. If you understand where the terms come from, they seem a little less confusing.

Are You Lecturing in Russion?

We have our fair share of acronyms in the HVAC/R industry. Used properly; acronyms speed up communication by reducing long polysyllabic phrases to a few letters. For example, speakers would get a bit winded if they used the phrase “heating, ventilating, air conditioning, and refrigeration” repeatedly in a conversation. The abundance of industry specific acronyms and the use of more than one acronym for the same item can be truly bewildering to students. For example, one major valve manufacturer uses the acronym TEV to represent “Thermostatic Expansion Valve,” while another uses the acronym TXV for the same thing. They do not represent two different types of components, just two different ways to abbreviate the word "expansion."

When introducing a new topic, using acronyms can lead to confusion and misunderstanding. Worse, students can start to pick up the jargon, but use it incorrectly. It can be difficult for teachers who have had years of experience with HVAC/R techno-speak to remember that the acronyms we casually throw around often have no meaning for our students. Imagine listening to a lecture in which every important concept was in Russian! For example: “The evaporator delta T is controlled by the TEV adjustment, the return air wb, and the CFM.” Now I believe that most any air conditioning instructor understands this sentence, but it is essentially unintelligible to many air conditioning students. It might as well be in Russian! Replacing the HVAC/R specific jargon with the wingdings font it looks like “The evaporator delta T is controlled by the TEV adjustment, the return air wb, and the CFM.” THAT is what this sentence looks like to a new student!

In general it is a good idea to resist using an acronym for something until that item or process has been discussed. Otherwise, the acronym will appear to students to be a mysterious grouping of letters used by air conditioning shaman to communicate with each other. The acronyms and jargon are like a secret language which they are not familiar with. I believe that language which is largely acronym free promotes better understanding, but some acronyms are so common that students really do need to eventually learn them. It is much easier to remember an acronym if you understand what the letters stand for. When using an acronym for the first time make sure and explicitly spell out what the letters represent, this will increase student’s understanding and retention of the term.

Of course, students must still learn the HVAC/R language. Having a solid grasp of the terminology is necessary to make use of essential technical literature produced by equipment manufacturers. In Fundamentals of HVAC/R, we always use the complete word or phrase before introducing an acronym. It helps to explain concepts plainly, and then introduce the technical terminology that is used to refer to the concept. The students are more likely to remember the terminology if it is logically connected to something they understand.

Fundamentals of HVAC/R has a unique abbreviation and acronym dictionary to help students learn the language of HVAC/R. The acronym dictionary is very useful when students are reading industry literature and need help with a particular abbreviation or acronym. They can find out exactly what is meant by a particular acronym or abbreviation in Appendix C which lists the definition of common acronyms and abbreviations used in HVAC/R.

It's Called a Compressor Because ..

How often have your students asked for study guides and hints before tests? Tell them that the hints are built into the terminology. In many cases, HVAC/R terms define themselves. The names for most components and processes are not randomly chosen, they are frequently drawn from general vocabulary to describe a component or process. For example, a compressor compresses gas. The word compress means to make smaller. When you squeeze something you make it smaller, or compress it. The compressor raises the pressure and temperature of the gas by squeezing it, making its volume smaller. If the students understand that compress means to squeeze, they should have no trouble remembering what the compressor does.

To truly understand HVAC/R terminology students should not simply memorize a list of attributes for the rather large number of HVAC/R terms, but should connect the function to the name. Making these connections also increases memory retention. The method that a compressor uses to accomplish its work is used to describe the types of compressors. Reciprocate means to go back and forth: a reciprocating compressor uses pistons that go back and forth in a cylinder. A scroll is spiral: scroll compressors use intermeshing spirals or scrolls to compress the gas. A screw compressor uses intermeshing auger shaped screws to compress the gas. Connecting the name to the function will help students get a mental picture of the device and increase both understanding and memory retention.

All the components of the refrigeration cycle have names that either describe their function or describe them physically. The key is for students to understand where the name comes from. If students understand that orifice is simply a three syllable word for hole, they should have not problem remembering what an orifice is. One of the reasons I believe in covering the science behind the refrigeration cycle before trying to discus the refrigeration cycle is so that these connections can be made. If the students already understand the processes of evaporation and condensation, they will have no trouble remembering what evaporators and condensers do. This same technique can be used for many aspects of HVAC/R. In electricity potential difference literally means the difference in electrical potential between two points. The refrigerant terms zeotropic and azeotropic can be better understood if you explain the vocabulary they are built on. For most of us, these words are presented simply as arcane terms for refrigerants that are mixtures of two or more refrigerants. The fact that they differ by a single letter makes remembering the difference between the two difficult. Most students complain that the two terms are “all Greek to me!” In fact they do come from Greek roots. “Zeo” is to boil, “trop” is to turn, so zeotropic refrigerants turn, or change as they boil. Placing the letter “a” in front means “not.” For example: amoral means without morals. Similarly, azeotropic refrigerants do NOT turn or change when they boil. Give a few vocabulary lessons and increase your student’s understanding and memory retention. For more HVAC/R vocabulary tips check out the glossary in Fundamentals of HVAC/R, the largest glossary in any major HVAC/R text.

The Language of HVAC/R

Many students find the large number of technical terms used in HVAC/R confusing. To the uninitiated, HVAC/R has its own language of technical jargon that can become a barrier to learning. Confusion over terminology can lead to not clearly understanding crucial concepts. This problem is compounded by the use of acronyms and abbreviations that are frequently used when discussing common topics. For example, one major valve manufacturer uses the acronym TEV to represent “thermostatic expansion valve,” while another uses the acronym TXV for the same thing. In Fundamentals of HVAC/R, we keep technospeak to a minimum, preferring to use common, easily understood language whenever possible. Making a relatively simple concept seem highly technical by using an overabundance of jargon does not help students.

Of course, students must still learn the HVAC/R language. Having a solid grasp of the terminology is necessary to make use of essential technical literature produced by equipment manufacturers. To encourage students to learn the language, we always use the complete word or phrase before introducing an acronym. It helps to explain concepts plainly, and then introduce the technical terminology that is used to refer to the concept. The students are more likely to remember the terminology if it is logically connected to something they understand. For example, I have found that students just starting to learn the operation of the refrigeration cycle often can recite the order of components, but they have not made the connection between the component names and what they do. It is much easier to remember “TEV” if you know that “TEV” is an acronym for “thermostatic expansion valve” and you know that the refrigerant expands as it goes through the thermostatic expansion valve.

We have three resources in the back of the text deigned specifically to help students learn the language of HVAC/R: an acronym dictionary, an English language glossary, and a Spanish language glossary. When a student wonders exactly what is meant by a particular acronym or abbreviation, they can find it in Appendix C which lists the definition of common acronyms and abbreviations used in HVAC/R. The acronym dictionary is also very useful when students are reading industry literature and need help with a particular abbreviation or acronym. Students can use either the English language or Spanish language glossary to look up the definition of common HVAC/R terminology. Fundamentals of HVAC/R has a very complete glossary to help students learn the HVAC/R language. It has the largest number of defined terms of any major HVAC/R text and the terms are fully explained, including multiple definitions of the same term.

I sincerely believe that students and instructors alike will find that Fundamentals of HVAC/R is an invaluable aid in learning the language of HVAC/R.