Tag: energy

It’s Getting Hot In Here!

Published on by Brian FarnoLeave a comment

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

Basics of Compressors

Published on by johnball2014Leave a comment
Single Stage Portable Air Compressor

What is an air compressor?  This may seem like a simple question, but it is the heartbeat for most industries.  So, let’s dive into the requirements, myths, and types of air compressors that are commonly used.  Like the name implies, air compressors are designed to compress air.  Unlike liquids, air is a compressible gas, which means that it can be “squished” into a smaller volume by pressure.  With this stored energy, it can do work for pneumatic systems.

There are two main types of air compressors, positive displacement and dynamic.  The core component of most air compressors is an electric motor that spins a shaft.  Positive displacement uses the energy from the motor and the shaft to change volume in an area, like a piston in a reciprocating air compressor or like rotors in a rotary air compressor.  The dynamic types use the energy from the motor and the shaft to create a velocity with an impeller like centrifugal air compressors.  This velocity converts to a rise in pressure.

How do they work?  Most air compressors are driven by an electric or gas motor.  The motor spins a shaft to push a piston, turn a rotor, or spin a vane.  At the beginning of the air compressor, we have the intake where a low pressure is generated from the displacement to bring in the surrounding ambient air.  Once trapped, Boyle’s law states that when the volume decreases, the pressure increases.  For the dynamic type, the velocity and design will increase the air pressure.  The higher pressure will then move to a tank to be stored for pneumatic energy.  The amount of power required is dependent on the amount of air that needs to be compressed. 

Compressed air is a clean utility that is used in many ways, and it is much safer than electrical or hydraulic systems.  But most people think that compressed air is free, and it is most certainly not.  Because of the expense, compressed air is considered to be a fourth utility in manufacturing plants.  For an electrical motor to reduce a volume of air by compressing it, it takes roughly 1 horsepower (746 watts) of power to compress 4 cubic feet (113L) of air every minute to 125 PSI (8.5 bar).  With almost every manufacturing plant in the world utilizing air compressors much larger than 1 horsepower, the amount of energy needed to compress a large volume of air is extraordinary.

Let’s determine the energy cost to operate an air compressor to make compressed air by Equation 1:

Equation 1:

Cost = hp * 0.746 * hours * rate / (motor efficiency)

where:

Cost – US$

hp – horsepower of motor

0.746 – conversion KW/hp

hours – running time

rate – cost for electricity, US$/KWh

motor efficiency – average for an electric motor is 95%.

As an example, a manufacturing plant operates a 100 HP air compressor in their facility.  The cycle time for the air compressor is roughly 60%.  To calculate the hours of running time per year, I used 250 days/year at 16 hours/day for two shifts.  So operating hours equal 250 * 16 * 0.60 = 2,400 hours per year.  The electrical rate at this facility is $0.10/KWh.  With these factors, the annual cost for operating the air compressor can be calculated by Equation 1:

Cost = 100hp * 0.746 KW/hp * 2,400hr * $0.10/KWh / 0.95 = $18,846 per year in just electrical costs.

So, what is an air compressor?  The answer is a pneumatic device that converts power (using an electric motor, diesel or gasoline engine, etc.) into potential energy stored as pressurized air.  Efficiency in using compressed air is very important.  EXAIR has been manufacturing Intelligent Compressed Air Products since 1983.  We are able to save you money by reducing the amount of compressed air you use.  If you need alternative ways to save money when you are using your air compressor, an Application Engineer at EXAIR will be happy to help you.  We even have a Cost Savings Calculator to find the annual savings and payback period; and you will be amazed at how much money can be saved. 

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Photo: Technical Illustration of a portable single-stage air compressor by Brain S. Elliot.  Creative Commons CC BY-SA 4.0

INDIANA: Energy Rebates and EXAIR Save You Money On Top of Compressed Air Savings

Published on by Brian FarnoLeave a comment

The energy rebates described below are available throughout the country, not just Indiana – but here is the latest example.

Here in Cincinnati we border two states, our bypass loop actually goes through both of them, Kentucky and Indiana. Indiana is a state that most may fly over or if you are going anywhere it may be to go to Indianapolis, myself, I have a few ties to the state elsewhere, from racing motorcycles at Putnam Park west of Indy, my niece attending the prestigious Rose-Hulman Institute of Technology, to my previous career where I installed CNC machines in various parts of the state. While many may think the state is a giant wind power farm, there is a great deal of industry and manufacturing throughout the state including pharmaceutical and medical devices, mining, and transportation. The leading energy provider for the state, Duke Energy, also supports these manufacturers with programs to incentivize (through rebates) products which increase efficiency.

We’ve mentioned energy rebates previously and I have recently had the chance to help a customer with their energy rebate. More often than not, these rebates are an after thought, I hope that after reading this we can help you to check with your local service provider to see if they offer a similar process – they are available throughout the country from MANY electricity providers. The process for this customer was based off purchasing a single Soft Grip Safety Air Gun with Stainless Steel Mini Super Air Nozzle. The rebate was focused on the engineered air nozzle. For a 1/8″ NPT nozzle, it must consume 10 SCFM or less at 80 psig inlet pressure. For a 1/4″ NPT nozzle, they have to consume 17 SCFM or less at 80 psig. The fact the nozzle was assembled onto a Soft Grip Safety Air Gun enabled the customer to apply for a rebate for the full cost of the whole air gun.

EXAIR Model 1299SS – Soft Grip Safety Air Gun w/ Stainless Steel Mini Super Air Nozzle

The value of the rebate for Indiana where Duke is the energy supplier is $40.00 USD per engineered nozzle installed. The rebate is capped at 75 percent of the project cost in Indiana. The current cost of the 1299SS is $134.00, which enables this customer to the full $40.00 for each Safety Air Gun with Mini Super Air Nozzle they install. This is one of the simplest prescriptive rebates in the Duke Energy program. The main focus here is to conserve compressed air which ultimately puts more energy available to the rest of the grid. The engineered nozzle prescriptive rebate is just one way that Duke Energy customers in the state of Indiana can save.

If you are in the state of Indiana (OR ANYWHERE ELSE IN THE USA) and would like to discuss whether the Safety Air Guns or any point of use compressed air application in your facility can be improved, contact an Application Engineer. The truth is we all love saving a customer their resources, whether it be compressed air, electricity, liquid, or good old-fashioned cash.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Heat Transfer – How Energy Can Move

Published on by codybiehleLeave a comment

Heat. One word can bring to mind so many different things from cooking to sun tanning. But what is heat and how does it move. Heat is essentially a form of energy that flows in the form of changing temperatures; this form of energy will flow from high to low. When you describe something as being hot, you are actually describing that the item in question has a higher temperature than your hand thus the thermal (heat) energy is flowing from that object to your hand. This phenomenon is what is referred to as heat transfer. Heat transfer can be observed all the way down to the atomic scale with the property known as specific heat. Every molecule and atom can carry a set amount of energy which is denoted by specific heat; this value is the ration of energy (usually in Joules) divided by the mass multiplied by the temperature (J/g°C).

Energy moving through atoms in an object

But how does this heat move from object to object? On the atomic scale, the atoms are storing the energy which will cause electrons to enter into an excited state and rapidly switch between shells. When the electron returns back 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 a 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.

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 with the higher temp to the object with 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 the thermal energy will flow from the water to the ice.

Convection
Convection is the transfer of thermal energy 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 in order to determine the rate at which heat will be transferred. The low the specific heat of a molecule the faster and more volume of the fluid will need to move in order to get full affect of convection. Convection is used in modern ovens in order to get a more even heat through out the food while cooking.

Radiation
Radiation is the transfer of thermal energy through empty space and does require a material between the two objects. Going back to the 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.

EXAIR’s engineered compressed air products are used every day to force air over hot surfaces to cool, as well as dry and/or blow off hot materials. Let us help you to understand and solve your heat transfer situations.

If you have any questions about compressed air systems or want more information on any of EXAIR’s products, give us a call, we have a team of Application Engineers ready to answer your questions and recommend a solution for your applications.

Cody Biehle
Application Engineer
EXAIR Corporation
Visit us on the Web
Follow me on Twitter
Like us on Facebook

The picture “Energy Transfer – Heat” by Siyavula Education is licensed under CC BY 2.0