Heat Transfer (Conduction, Convection, Radiation)

Thermal energy moves from warmer regions to cooler ones through conduction, convection, and radiation. Objects continuously lose heat until they achieve thermal equilibrium, meaning they reach the same temperature as their environment. For instance, a steaming mug of tea will gradually cool until it matches the temperature of the room.

But how that mug looses that heat is what this blog is all about.

CONDUCTION:

Thermal energy moves through solids mainly via conduction. This phenomenon happens when two solid items with varying temperatures come into contact, enabling heat to transfer from the warmer object to the cooler one. For instance, in the scenario of a hot coffee mug resting on a cold table, the thermal energy shifts from the mug to the table beneath it.

CONVECTION:

Convection refers to the movement of fluids, whether they are liquids or gases, and can occur naturally or be induced by external forces. Fluids can either absorb or release heat, depending on their temperature. Natural convection happens due to variations in density; for instance, steam rises from the top of the mug as the steam rises, colder air is cycled in.

RADIATION:

While the coffee emits infrared radiation as it loses heat, this process is generally less significant compared to conduction and convection in the context of a cup of coffee. This type of heat loss can be felt by holding your hand near a warm coffee cup as shown.

No matter how the heat is transferred to an object, if it needs to be cooled there is a good chance that one of our Application Engineers has approached a similar issue and can help. To discuss, contact us, and we will walk through the best method to eliminate the heat from within your application.

Jordan Shouse
Application Engineer

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It’s Getting Hot In Here!

Okay, if you did not finish the song lyrics when reading the title, it’s okay, we can still be friends. In all actuality, the temps are warming up here in the MidWest as we prepare for our false Spring as indicated by the freezing temps and snow we received earlier this week. There is one thing that has stayed constant and that is the methods of heat generation.

1 – Kettle-convection-conduction-radiation

Heat generation is a result of energy conversion. The conversion of energy to do work, whether it is actual voltage going through a transformer that operates a neon sign to light up the roadside sky or energy from a hydraulic ram that is compacting recycled paper into a bundle and the hydraulic fluid is being pressed in and out of cylinders from a pump, all of it will have some form of a heat byproduct. This heat then gets transferred and how it is transferred can be helpful to know.

2 – Energy Transfer – Heat

At the molecular level, atoms store the energy that will cause electrons to enter into an excited state and rapidly switch between shells. When the electron returns to a lower shell (closer to the nucleus), energy is released; the energy released is then absorbed by atoms at a lower energy state and will continue until the thermal energy is equal between the two objects. Heat has four fundamental modes of transferring energy from surface to surface, and they are as follows:

Advection
Advection is the physical transport of fluid from point A to point B, which includes all internal thermal energy stored inside. Advection can be seen as one of the simpler ways of heat transfer.

Radiation
Radiation is the transfer of thermal energy through empty space and does require a material between the two objects. Going back to how thermal energy is released from atoms when the electron returns to a lower energy shell, the energy is released in the form of light ranging from infrared light to UV light. Energy in the form of light can then be absorbed by an object in the form of heat. Everyone experiences radiation transfer every day when you walk outside; the light from the sun’s radiation is what keeps this planet habitable.

Conduction
Conduction can also be referred to as diffusion and is the transfer of energy between two objects that have made physical contact. When the two objects come into contact with each other, thermal energy will flow from the object at the higher temp to the object at the lower temp. A good example of this is placing ice in a glass of water. The temperature is much lower than the room temperature. Therefore, thermal energy will flow from the water to the ice.

Convection
Convection is the thermal energy transfer between an object and a fluid in motion. The faster the fluid moves, the faster heat is transferred. This relies on the specific heat property of a molecule to determine the rate at which heat will be transferred. When a molecule has a lower specific heat, it takes faster motion and larger volumes to achieve the full effect of convection transfer. Convection is used in modern ovens to get a more even heat throughout the food while cooking.

No matter how the heat is transferred to an object, if it needs to be cooled there is a good chance that one of our Application Engineers has approached a similar issue and can help. To discuss, contact us, and we will walk through the best method to eliminate the heat you need to.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – “Kettle-convection-conduction-radiation” by P.wormer is licensed under CC SA 3.0
2– “Energy Transfer – Heat” by Siyavula Education is licensed under CC BY 2.0

Built to Last

The past few months many of our lives have been altered in some fashion due to COVID-19. Personally, my three daughters began staying home full time and attending school through distance learning.  I myself switched to working some alternate shifts which EXAIR changed to in order to optimize our availability to our customer base as well as protect our team members effectively. I know many in manufacturing that have been furloughed. Even worse, some have been forced to work in unsafe conditions.

All of this has made me thankful I am part of a team that cares about our employees first, and then we all work towards ensuring our customers are taken care of. Our new shift structure has also given me time to reflect on many aspects of my life.

When I was younger, like many kids, I always wanted something I received to be new. I didn’t want an older hand me down bicycle, I wanted new.  Little did I know I would reach a point in life where I prefer things to be a little older, a little more seasoned, even broken-in if you will.  The days are here where disposable is what everyone expects whenever they purchase anything. Repairable is often a thing of the past and or requires specialty tools and or software.  I’ve been recently working on lots of small engines from friends and family members yard equipment and recreational vehicles.

I’ve worked on a 1970’s era Stihl chainsaw that the only safety is the weight of the saw and an on/off toggle switch, up to an imported 4 wheeler that instead of buying a single piece or carburetor kit, most people throw them away and buy new.  Something about the older equipment makes me think I was born in the wrong era. The time of working hard for what you make and taking pride in products lasting a lifetime is often gone from consumer-grade products.  When carburetors are riveted together to make them faster and cheaper to assemble, but also not easily repairable, the chance of someone repairing it 40 years from now diminishes.

It could be that I am closer to 40 than I am to 30, however, I find that being able to source parts direct from a manufacturer as well as being able to get support direct from the manufacturer is something I desire. This could also be because this is how we do business at EXAIR. Our compressed air products all carry a 5 year Built to Last Warranty, we service them, sell replacement parts for them and take pride in their ability to last.

There are few items that I am okay with going a cheap route on, spare screwdrivers, you know the ones you use as pry bars and oil filter punches, and anything I know I am only going to use once and I am okay if it breaks as long as it is worth a laugh.  When I went to repair a weed eater for a neighbor I found the engine casing was plastic, there was barely anything to the motor and the lack of maintenance on his part as well as the ethanol in the fuel with lack of stabilizer had gummed up the entire fuel system.

This was a disposable weed eater and he admitted it wasn’t cheap but he also knew it wasn’t a big brand name. Experiencing this, made me laugh.  I went to my older weed eater that has seen many days. It was bought used at an auction. I gladly started it up for him and offered to loan it out whenever he needed. That weed eater was built to withstand its use. Parts are readily available and it is so popular there are many of the parts reproduced through third party factories pretending to be the company.

Next up on my project list may be the biggest project yet, a tiller that is far older than I am. This again has been brought on by the want for a healthy garden and the ability to also help neighbors and friends when they are ready for their gardens.  Rather than looking new, I started at the old, something I knew was built for hard work, and was ready for the task.  I doubt there is a single piece of aluminum on this thing, it has probably seen more sweat throughout its years than I have in my lifetime.  First, the research though.  Parts, service manuals, and then the negotiation of the purchase. (Both with my wife, and the seller. Separately of course.)

Here at EXAIR, we can get nostalgic over some of our products and processes as well. At the same time, we continuously flex and work with the matters a hand. If you have an old product of ours that you think may not be worthy of use, give us a call. With a few pictures and some information, our team of Application Engineers should be able to help determine if it is in good working order or not.  If we cannot determine from pictures, we can always receive the unit in and inspect it for you. In the event it is not in working condition, we more often than not can refurbish the unit and have you back up and running within a few days.  Our Super Air Knives are a product that often gets overlooked when they get covered in debris from a process. We can inspect them, clean them, and often restore them to flowing like a brand new knife.

Brian Farno
Aging Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Watch EXAIR Webinars On-Demand

That’s right, just like your local cable or satellite TV provider, EXAIR offers On-Demand content that can be streamed and used for training, education, help with cost justification, or improve awareness around compressed air costs and safety.

The best part about this content is that you don’t have to pay for it, simply register on our website (where your information is not shared) and go to the Webinars section of our Knowledge Base.  Then gain access to the library of five webinars that have all been broadcast around compressed air safety, efficiency, and optimization.

EXAIR.com – Webinars On-Deman

The current On-Demand offering is listed below:

Intelligent Compressed Air Solutions for OSHA Compliance
Intelligent Solutions for Electrical Enclosure Cooling
Optimize Your Compressed Air System in 6 Simple Steps
Simple Steps for Big Savings
Understanding Static Electricity

The most recent webinar we created is currently only On-Demand for registered attendees and will soon be added to the Knowledge Base library.  If you did not get to see it live, the content was extremely helpful for anyone that works within a facility that uses compressed air.  Use This Not That – 4 Common Ways To Save Compressed Air In Your Plant, keep an eye out for the release date in our On-Demand section.

If you would like to discuss any of the webinar topics further, please feel free to reach out to an Application Engineer.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF