Lab Magic!

Most of us think of labs as a chance for students to practice the practical application of HVAC/R skills: brazing, charging, wiring, or troubleshooting to name a few. Certainly, students must practice their practical skills in the lab. I believe that the lab can also be instrumental in teaching more abstract concepts like gas laws or ohm’s law.

I have found that most HVAC/R students are visual and tactile learners. They learn more by seeing, touching, and doing than by reading, writing, and listening. Frequently the desire “to do” is part of what motivated them to study air conditioning in the first place, as opposed to a more academic pursuit. They arrive at the HVAC/R class excited and ready “to do”, and then we provide them with an opportunity to learn gas law formulas and ohms law. Normally we teach these subjects with an extra helping of mathematical equations. The numbers in the equations are typically all presented as part of a hypothetical example or problem. For those of us with a good understanding of the theory and the concept, the meaning is clear. For students who are still trying to understand the difference between a volt, an amp, and an ohm the problem simply becomes an exercise in math. They are not really interested in math formulas, and telling them the formulas are good for them is a bit like forcing them to take their castor oil. To overcome this, get them in the lab early and use numbers from real objects.

For ohms law, have the students measure the resistance of a strip heater, measure the voltage at the source, and then have them use ohm’s law to predict the amp draw. Next, have them operate the heater and measure its amp draw. The readings won’t be perfect, but they will be close enough to get the point across. Then do the same thing with two heaters in series and then two in parallel. They can read the individual resistance of each heater and then the combined circuit resistance to show how series and parallel resistances work. The key is to have the numbers associated with something real.

Gas behavior also works well. You can talk about the boiling point being tied to the pressure all day long and not really get the point across that boiling does not have to occur at a high temperature. This is because the information contradicts the student’s life experience – the only thing they have seen boil was hot. Put water in a flask, attach the flask to a vacuum pump, and start the vacuum pump. The water will boil at room temperature. Invite the students to touch the flask and ask questions. I have yet to see anyone who does not like this experiment. It is simple, does not take a lot of equipment, and really makes an impact.

There are many other similar labs we run whose purpose is to demonstrate an important concept. Students can quickly learn fundamental electrical circuits in the lab as well. Just make sure students know not to energize any circuits before having an instructor checks them. After the students start to connect the concepts to something that is real, then they will start to ask questions. Now you can start to use hypothetical examples and the students have a mental image of a real device to give the discussion meaning.

For some more ideas about these types of labs, take a look at the Lab Manual by David Skaves. It contains an entire section of labs labeled as Properties labs. These labs teach students about physics properties that make HVAC/R work. Although this Lab Manual is written to accompany Fundamentals of HVAC/R, it works well with any text because it is organized by subject matter with sections on Fundamentals, Properties, Refrigeration, Accessories, Controls, Electricity, Maintenance, Gas Heat, Oil Heat, and Electric Heat. Each section has several labs.

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.

Show Me the Money!

There is no secret that all of us teaching air conditioning are experiencing a boom in enrollment. A frustration that many of these new students share is limited financial resources. Truth be told, that is precisely why they are air conditioning students – they are working to improve their financial fortunes. Sometimes they end up trying to decide whether to buy the required texts, or the required tools. Both can represent a sizeable investment. An unemployed student can find it difficult to afford both. Although the schools are trying to help, most schools have limited resources right now as well. Some major corporations and industry organizations are offering significant scholarships to people studying Air Conditioning and Refrigeration. The ones that I know about are the AHRI Rees Scholarship, the Grainger Tools for Tomorrow Scholarship, and the Home Depot Trade Scholarship. I am sure there are more. The AHRI Rees Scholarship Foundation awards approximately 15 scholarships of up to $2,000 each to qualified students who are enrolled in an HVACR program at an accredited institution. The Grainger Tools for Tomorrow Scholarship provides a $2,000 scholarship plus a custom set of tools from Grainger to approximately 100 trade students nationwide. Home Depot is offering $1,000 scholarships to 500 trade students. Home Depot is also going to award the school each scholarship student attends an additional $1,000. One of these scholarships could be the difference between a promising student finishing or having to drop out for financial reasons. Together that is 615 more future trades professionals who do REAL work right here in the USA to build a brighter tomorrow. God bless them.

However, to win a scholarship you must apply. You would be surprised how difficult it can be to get wrench minded students to fill out scholarship applications, write essays, and apply their literary skills for a chance to win a scholarship. I am proud to say that the first Tools For Tomorrow Scholarship recipient at Athens Tech was one of my students, Ricky Byrd (Article). Ricky was a very deserving recipient and he represents my program and our profession well. There were other capable students who chose not to apply because they were required to write a short essay. The folks from Grainger came to my department to award Ricky the scholarship and that changed everyone’s perspective. Think of the scholarship application as practice for seeking employment. To sell yourself to future employers you need to be able to explain in writing and verbally what you can offer that they cannot do without. If you just sit around waiting for the world to discover how brilliant you are, you most likely will be waiting for a long time.

For information on how to apply check out the following links.

AHRI Rees

Grainger

Home Depot

If you don’t snag one of these scholarships, don’t despair. Often local organizations have scholarships that are not as well publicized. Check with local contractor associations or local RSES chapters to see if they have any scholarships.

The BIG Showis Almost Here

The AHR Expo is coming up January 25 in Orlando Florida. The AHR Expo is the granddaddy of all air conditioning industry shows. It is co-sponsored by two of the HAVC/R industry heavy hitters: ASHRAE and AHRI. This is truly a world class show with people and companies from all over the globe. My experience has been that it is really impossible to look at all the exhibits in a day because there is so much to see. If you are located anywhere close to Orlando and can find a day to visit the expo, it is well worth your time. Instructors and students can get so much free literature that it will take you hours just to read it all. There are many free seminars every day for discussion of new technologies and products. The AHR Expo is usually where HVAC/R companies roll out their latest and greatest, so it is a perfect place to see where the industry is heading. Perhaps most useful to instructors are the contacts you can make with OEM suppliers, manufacturers, wholesalers, and industry technical gurus of all stripes. Of course the expo will be located in the land of fun and sun, making the overall trip more pleasant. However, you will probably have to wait until after the show to see Mickey because there is just so much to do at the expo. Click on AHR Expo to learn more about the show.

Naturally, when you get home you will be thinking about how to incorporate what you saw in the show into your program. One way is through links to the online literature of HVAC/R companies. A good way to do this is to add links in MyHVACLab at appropriate places in the program. This gives the information some structure and makes it more meaningful than a long list of unrelated hyperlinks. Although on advantage of MyHVACLab is that it is a complete program out of the box, another big advantage is that it is easy to modify to fit your needs. Click on MyHVACLab to learn more about MyHVACLab or Fundamentals of HVAC/R, the AHRI endorsed text that MyHVACLab supports. So pack your sunscreen and head down to the land of fun and sun to see the world’s largest air conditioning show!