Engine Block Heaters and Battery Heaters

Posted by PITHOCRATES - February 19th, 2014

Technology 101

As Matter loses Heat it shrinks from a Gas to a Liquid to a Solid

There is no such thing as cold.  Cold is simply the absence of heat.  Which is a real thing.  Heat.  It’s a form of energy.  Warm things have a lot of energy.  Cold things have less energy.  The Kelvin scale is a measurement of temperature.  Like degrees used when measuring temperature in Celsius or Fahrenheit.  Where 32 degrees Fahrenheit equals 0 degrees Celsius.  And 0 degrees Celsius equals 273.15 kelvin.  Not ‘degrees’ kelvin.  Just kelvin.

When something cools it loses heat energy.  The molecular activity slows down.  Steam has a lot of molecular activity.  At 212 degrees Fahrenheit (100 degrees Celsius or 373.15 kelvin) the molecular activity decreases enough (i.e., loses energy) that steam changes to water.  At 32 degrees Fahrenheit (0 degrees Celsius or 273.15 kelvin) the molecular activity decreases enough (i.e., loses energy) that water turns into ice.

The more heat matter loses the less molecules move around.  At absolute zero (0 kelvin) there is no heat at all.  And no molecular movement.  Making 0 kelvin the ‘coldest’ anything can be.  For 0 kelvin represents the absence of all heat.  As matter loses heat it shrinks.  Gases become liquid.  And liquids becomes solid.  (Water, however, is an exception to that rule.  When water turns into ice it expands.  And cracks our roadways.)  They become less fluid.  Or more viscous.  Cold butter is harder to spread on a roll than warm butter.  Because warm butter has more heat energy than cold butter.  So warm butter is less viscous than cold butter.

Vehicles in Sub-Freezing Temperatures can Start Easily if Equipped with an Engine Block Heater

In a car’s internal combustion engine an air-fuel mixture enters the cylinder.  As the piston comes up it compresses this mixture.  And raises its temperature.  When the piston reaches the top the air-fuel mixture is at its maximum pressure and temperature.  The spark plug then provides an ignition source to cause combustion.  (A diesel engine operates at such a high compression that the temperature rise is so great the air-fuel mixture will combust without an ignition source).  Driving the piston down and creating rotational energy via the crank shaft.

For this to happen a lot of things have to work together.  You need energy to spin the engine before the combustion process.  You need lubrication to allow the engine components to move without causing wear and tear.  And you need the air-fuel mixture to reach a temperature to burn cleanly and to extract as much energy from combustion as possible.  None of which works well in very cold temperatures.

Vehicles operating in sub-freezing temperatures need a little help.  Manufacturers equip many vehicles sold for these regions with engine block heaters.  These are heating elements in the engine core.  You’ll know a vehicle has one when you see an electrical cord coming out of the engine compartment.  When these engines aren’t running they ‘plug in’ to an electrical outlet.  A timer will cycle these heaters on and off.  Keeping the engine block warmer than the subfreezing temperatures.

The Internal Combustion Engine is Ideal for use in Cold Temperatures

At subfreezing temperatures engine oil because more viscous.  And more like tar.  This does not flow well through the engine.  So until it warms up the engine operates basically without any lubrication.  In ‘normal’ temperatures the oil heats up quickly and flows through the engine before there’s any damage.  At subfreezing temperatures oil needs a little help when starting.  So the oil sump is heated.  Like an engine block heater.  So when someone tries to start the engine the oil is more like oil and less like tar.

Of course, for any of this to help start an engine you have to be able to turn the engine over first.  And to do that you need a charged battery.  But even a charged battery needs help in sub-freezing temperatures.  For in these temperatures there is little molecular action in the battery.  And without molecular activity there will be little current available to power the engine’s starter.  So there are heaters for batteries, too.  Electric blankets or pads that sit under or wrap around a battery.  To warm the battery to let the chemicals inside move around more freely.  So they can produce the electric power it needs to turn an engine over on a cold day.

Once an engine block, the engine oil and battery are sufficiently warmed by external electric power the engine can start.  Once it warms up it can operate like it can at less frigid temperatures.  The engine alternator powers the electrical systems on the vehicle.  And recharges the battery.  The engine coolant heats up and provides heat for the passenger compartment.  And defrosts the windows.  Once the engine is warm it can shut down and start again an hour or so later with ease.  Making it ideal for use in cold temperatures.  Unlike an electric car.  For the colder it gets the less energy its batteries will have.  Making it a risky endeavor to drive to the store in the Midwest or the Northeast during a winter such as this.  Something people should think about before buying an all-electric car.

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Melting Snow and Ice

Posted by PITHOCRATES - February 5th, 2014

Technology 101

When Temperatures fall below Freezing Liquid Water turns into Solid Water

You know what the best thing about water is?  You don’t have to shovel it.  Well, that, and its life-giving properties.  Let’s face it.  We couldn’t survive without the stuff.  We couldn’t grow food.  We even couldn’t live without drinking water.  So perhaps its life-giving properties is the best thing about water.  But a close second would be that thing about not having to shovel it.

When it rains water soaks into our green areas.  It runs off driveways and sidewalks into green areas.  And into streets.  Where it runs off into a storm drainage system.  Which takes it to a river or lake.  The rain lets our gardens grow.  And any excess water conveniently just goes away.  We may have a puddle or two to slosh through.  But even those go away without us having to do anything.  Water is nice that way.  As long as the temperature is above its freezing point.

When the temperature falls below the freezing point of water bad things start to happen.  Liquid water turns into solid water.  And hangs around for awhile.  Accumulating.  On our driveways, sidewalks, porches and roads.  It’s pretty much everywhere we don’t want it to be.  Making it difficult to walk.  And drive.  We slip and fall a lot in it.  The sun may melt it a little during the day.  Creating puddles of water where the snow once was. But when the sun sets those puddles freeze.  And become even more slippery.  Making solid water more dangerous than liquid water.  So a big part of making it through winters in northern climes, then, is transforming solid water back into the liquid form.

Even though Bourbon melts Ice Cubes Bourbon would be a Poor Choice to melt Snow and Ice

All material can be in three different stages.  It can be a solid.  A liquid.  Or a gas.  What determines the phase of this material depends on a couple of things.  Mostly temperature and pressure.  And the chemical properties of the material.  At ambient temperature and pressure material typically exists stably in one phase.  Water, for example, is stable in the liquid phase on an 80-degree summer day.  Allowing us to swim in it.  While on a freezing February day it is stable in the solid phase.  Which is why we hold the Winter Olympics in February.  The cold temperatures give us the best solid water conditions.

If we raise the temperature of water we can turn it from a liquid to a gas.  We could also do this by lowering the ambient air pressure.  Such as putting it into a vacuum.  For a liquid remains a liquid as long as the vapor pressure (the tendency for particles to escape from the liquid they’re in) of the liquid is less than the ambient air pressure.  If we lower the ambient air pressure below the vapor pressure of the liquid we can lower the boiling point of that liquid.  This is why different liquids have different boiling points.  They have different vapor pressures.  Oxygen has a very high vapor pressure and requires a high pressure and cold temperature to keep oxygen in a liquid phase.

When we take ice cubes out of the freezer and add them to a glass of bourbon they melt.  Because the ambient temperature outside of the freezer is above the freezing point of water.  So the solid water changes its phase from solid to liquid.  It would follow, then, that pouring bourbon on snow and ice would help melt it.  Of course we don’t do that.  For wasting bourbon like that would be criminal.  Not to mention costly.  Even if you used the cheap stuff.  Making bourbon a poor choice for melting snow and ice.

Salt dissolves into a Brine Solution that lowers the Melting Point of Snow and Ice

We see that a material will change its phase at different temperatures and pressures.  Which is good to know.  But it doesn’t help us to melt snow and ice during winter.  For we can’t lower the atmospheric air pressure to lower the boiling and melting points of water.  And we can’t raise the ambient temperature above the melting point of water.  If we could our winters would probably be a lot more comfortable than they are now.  So because when we can’t change the air pressure or temperature of the ambient environment the snow and ice is in we do something else.  We use chemistry to lower the melting point of snow and ice.  And the most common chemical we use is salt.

To melt snow and ice salt needs heat and moisture.  The moisture comes from the snow and ice.  Or from the humidity in the air.  The heat comes from the warmth of the earth or air.  Heated by the sun.  It also comes from the friction between tires and the road.  When salt comes into contract with water and heat it dissolves into a brine solution.  And this brine solution has a much lower melting point than water.  Which in turn lowers the melting point of the snow and ice it comes into contact with.  Allowing it to be in the liquid phase at temperatures below freezing temperatures.  Melting that snow and ice so it can run off like rain water.

The warmer it is when it snows the quicker salt will melt that snow.  While the colder it is the longer it takes to melt.  If it gets too cold (around 15 degrees Fahrenheit) salt proves to be ineffective.  In temperatures below 15 degrees Fahrenheit other chemicals work better.  Such as calcium chloride.  But calcium chloride is more costly than sodium chloride (salt).  Ambient temperatures, time of day, sunny or cloudy, wind, etc., all determine the chemical to use.  And the amount of chemical to use.  They consider all of these factors (and more) before sending those ‘salt’ trucks out on the roads.  Allowing us to drive in the worst of winters just as we drive in the best of summers.  It may take more time.  And there may be a little more cussing.  But we still go to work, take our kids to school, go shopping, etc., when it snows.  Thanks to chemicals.  Chemistry.  And the people that put those chemicals and that chemistry to work.

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Feedback Loop Control System

Posted by PITHOCRATES - October 30th, 2013

Technology 101

Living through Winters became easier with Thermostats

When man discovered how to make fire it changed where we could live.  We no longer had to follow the food south when winter came.  We could stay through the winter.  And build a home.  As long as we could store enough food for the winter.  And had fire to stay warm.  To prevent our dying from exposure to the cold.

There’s nothing like sitting around a campfire.  It’s warm.  And cozy.  In large part because it’s outside.  So the smoke, soot and ash stayed outside.  It wasn’t always like that, though.  We used to bring that campfire inside the home.  With a hole in the roof for the smoke.  And families slept around the fire.  Together.  Even as some fornicated.  To propagate the species.  But that wasn’t the worst part about living around an indoor campfire.

Your distance from the fire determined how hot or cold you were.  And it was very hot by it.  Not so hot away from it.  Especially with a hole in the roof.  Worst, everyone got colder as the fire burned out.  Meaning someone had to get up to start a new fire.  The hard way.  Creating an ember.  Using it to start some kindling burning.  Then adding larger sticks and branches onto the kindling until they started to burn.  Which was a lot harder than turning the thermostat to ‘heat’ at the beginning of the heating season and forgetting about it.  Then turning it to ‘off’ at the end of the heating season.

A Feedback Loop Control System measures the Output of a System and Compares it to a Desired Output

Replacing the indoor campfire with a boiler or furnace made life a lot simpler.  For with a supply of fuel (natural gas, fuel oil, electricity, etc.) the fire never burned itself out.  And you never had to get up to start a new one.  Of course, that created another problem.  Shutting it off.

Boilers and furnaces are very efficient today.  They produce a lot of heat.  And if you let them run all day long it would become like a hot summer day inside your house.  Something we don’t want.  Which is why we use air conditioners on hot summer days.  So heating systems can’t run all day long.  But we can’t keep getting up all night to turn it off when we’re too hot.  And turning it back on when we’re too cold.  Which is why we developed the feedback loop control system.

We did not develop the feedback loop control system for our heating systems.  Our heating systems are just one of many things we control with a feedback loop control system.  Which is basically measuring the output of a system and comparing it to a desired output.  For example, if we want to sleep under a cozy warm blanket we may set the ‘set-point’ to 68 degrees (on the thermostat).  The heating system will run and measure the actual temperature (at the thermostat) and compare it to the desired set-point.  That’s the feedback loop.  If the actual temperature is below the desired set-point (68 degrees in our example) the heat stays on.  Once the actual temperature equals the set-point the heat shuts off.

The Autopilot System includes Independent Control Systems for Speed, Heading and Altitude

Speed control on a car is another example of a feedback loop control system.  But this control system is a little more complex than a thermostat turning a heating system on and off.  As it doesn’t shut the engine off once the car reaches the set-point speed.  If it did the speed would immediately begin to fall below the set-point.  Also, a car’s speed varies due to terrain.  Gravity speeds the car when it’s going downhill.  And slows it down when it’s going uphill.  The speed controller continuously measures the car’s actual speed and subtracts it from the set-point.  If the number is negative the controller moves the vehicle’s throttle one way.  If it’s positive it moves the throttle in the other way.  The greater the difference the greater the movement.  And it keeps making these speed ‘corrections’ until the difference between the actual speed and the set-point is reduced to zero.

Though more complex than a heating thermostat the speed control on a car is pretty simple.  It has one input (speed).  And one output (throttle adjustment).  Now an airplane has a far more complex control system.  Often called just ‘autopilot’.  When it is actually multiple systems.  There is an auto-speed system that measures air speed and adjusts engine throttles.  There is a heading control system that measures the aircraft’s heading and adjusts the ailerons to adjust course heading.  There is an altitude control system that measures altitude and adjusts the elevators to adjust altitude.  And systems that measure and correct pitch and yaw.  Pilots enter set-points for each of these in the autopilot console.  And these control systems constantly measure actual readings (speed, heading and altitude) and compares them to the set-points in the autopilot console and adjusts the appropriate flight controls as necessary. 

Unlike a car or an airplane a building doesn’t move from point A to point B.  Yet they often have more complex control systems than autopilot systems on airplanes.  With thousands of inputs and outputs.  For example, in the summer there’s chilled water temperature, heating hot water temperature (for the summer boiler), supply air pressure, return air pressure, outdoor air pressure, indoor air pressure, outdoor temperature, outdoor humidity, indoor temperature (at numerous locations), indoor humidity, etc.  Thousands of inputs.  And thousands of outputs.  And unlike an airplane these are all integrated into one control system.  To produce a comfortable temperature in the building.  Maintain indoor air quality.  Keep humidity levels below what is uncomfortable and possibly damaging to electronic systems.  And prevent mold from growing.  But not keep it too dry that people suffer static sparks, dry eyes, dry nasal cavities that can lead to nose bleeds, dry and cracked skin, etc.  To prevent a blast of air hitting people when they open a door.  To keep the cold winter air from entering the building through cracks and spaces around doors and windows.  And a whole lot more.  Far more than the thermostat in our homes that turns our heating system on and off.

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Another Electric Car bursts into Flames

Posted by PITHOCRATES - October 5th, 2013

Week in Review

One thing we learned from Breaking Bad was to respect the chemistry.  And that’s what batteries are.  Chemistry.  The kind of chemistry that’s a little on the dangerous side.  Unlike gasoline.  Which we can store relatively safely in tanks under our cars.  Where little chemistry goes on inside our gas tanks.  To use that gasoline to power our cars we have to do a couple of things.  We have to aerosolize it.  Combine it with oxygen.  Compress it.  Then ignite it.  Then and only then does it release its incredible energy.  Producing great heat in the engine.  But not the gas tank.  Which needs no cooling system.  It’s a little different in an electric car.

In a battery the chemistry is all local.  It produces electricity—and heat—where the chemicals are stored.  In the battery.  One of the problems with electric cars is their limited range.  And you fix this problem with bigger and more powerful batteries.  That can produce a lot of electricity—and heat—as they charge or power the car.  Making battery cooling a requirement for safe battery use.  To keep those chemicals under control.  But sometimes these chemical reactions go out of control.  Causing fires as cars re-charge in their garages.  Causing fires that grounded the new Boeing 787 Dreamliner.  And this (see Hot Wheels! Tape of Tesla Fire Has Stock Tanking by Dan Berman, Hot Stock Minute, posted 10/3/2013 on Yahoo! Finance).

Tape of a Tesla (TSLA) on fire is giving new meaning to the term “hot wheels.” The video was shot on Tuesday after a Model S sedan went up in flames…

In an e-mail sent to The New York Times, Tesla spokeswoman Elizabeth Jarvis-Shean wrote that the fire was caused by the “direct impact of a large metallic object to one of the 16 modules within the Model S battery pack.” The e-mail went on to say, “Because each module within the battery pack is, by design, isolated by fire barriers to limit any potential damage, the fire in the battery pack was contained to a small section in the front of the vehicle.”

Contained to a small section?  It looks like the fire engulfed the whole car.  All because of some metal debris thrown up from the roadway.  Of course, a way to protect against something like this in the future is to add a metal shield that can take a direct hit without damage.  Adding a thick piece of metal under the car, though, adds weight.  Which, of course, reduces range.

This is a problem with electric cars.  Improving safety results in a reduction in range.  Because it adds weight.  It adds weight, too, with gasoline-powered cars.  But one full tank of gas can hold a lot more energy that all the batteries can on an electric car.  And when you run out of gas all you have to do is stop at a conveniently located gas station and fill up.  Which takes about 10 minutes or so.  Unlike a recharge of an electric car.  Which can take anywhere between a half hour (with a high-voltage fast charger) to overnight in the garage plugged into a standard outlet.  Which is why electric cars are more of a novelty.  Those who have them typically have other more reliable cars for their main driving needs.  For though gasoline-powered cars catch fire, too, when they’re not on fire you know you’re going to get home.

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Heat Transfer, Conduction, Convection, Radiation and Microwave Cooking

Posted by PITHOCRATES - September 4th, 2013

Technology 101

At the Atomic Level Vibrating Atoms create Heat

We make life comfortable and livable by transferring heat.  And by preventing the transfer of heat.  In fact, once we discovered how to make fire our understanding of heat transfer began and led to the modern life we know today.

At the atomic level heat is energy.  Vibrating atoms.  With electrons swirling around and jumping from one atom to another.  The more these atoms do this the hotter something is.  There is little atomic motion in ice.  And ice is very cold.  While there is a lot of motion in a pot of boiling water.  Which is why boiling water is very hot.

How do we get a pot of water to boil?  By transferring heat from a heat source.  A gas or electric burner.  This heat source is in contract with the pot.  The heat source agitates the atoms in the pot.  They begin to vibrate.  Causing the pot to heat up.  The water is in contact with the pot.  The agitated atoms in the pot agitate the atoms in the water.  Heating them up.  Giving us boiling water to cook with.  Or to make a winter’s day pleasant indoor.

Fin-Tube Heaters create a Rising Convection Current of Warm Air to Counter a Falling Cold Draft

If you touch a single-pane window in the winter in your house it feels very cold.  Cold outside air is in contact with the glass of the window.  Which slows the movement of the atoms.  Bringing the temperature down.  This cold temperature doesn’t conduct into the house.  The heat conducts out of the house.  Because there is no such thing as cold.  As cold is just the absence of heat.

The warm air inside the house comes in contact with the cold window.  Transferring heat from the air to the window.  The atoms in the air slow down.  The air cools down.  And falls.  This is the draft you feel at a closed window.  Cold air is heavier than warm air.  Which is why hot air rises.  And cold air falls.  As the cold air falls it pulls warmer air down in a draft.  Cooling it off.  Creating a convection current.

To keep buildings comfortable in the winter engineers design hot-water fin-tube heaters under each exterior window.  Gas burners heat up water piping inside a boiler.  The heat from the fire transfers heat to the boiler tubes.  Which transfers it to the water inside the tubes.  We then pump this heating hot water throughout the building.  As it enters a fin-tube heater under a window the hot water transfers heat to the heating hot water piping.  Attached to this piping are fins.  The heat transfers from the pipe to the fins.  Which heats the air in contact with these fins.  Hot air rises up and ‘washes’ the cold windows with warm air.  As it rises it pulls colder air up from the floor and through the heated fins.  Creating a convection current of warm air rising up to counter the falling cold draft.

Microwave Cooking won’t Sear Beef or Caramelize Onions like Conductive or Radiation Cooking

If you’ve ever waited for a ride outside an airport terminal on a cold winter’s day you’ve probably appreciated another type of heat transfer.  Radiation.  Outdoor curbside is open to the elements.  So you can’t heat the space.  Because there is no space.  Just a whole lot of outdoors.  But if you stand underneath a heater you feel toasty warm.  These are radiators.  A gas-fired or electric heating element that gets very, very hot.  So hot that energy radiates off of it.  Warming anything underneath it.  But if you step out from underneath you will feel cold.  It’s the same sitting around a campfire.  If you’re cold and wet you can sit by the fire and warm up in the fire’s radiation.  Move away from the fire, though, and you’re just cold and wet.

We use all these methods of heat transfer to cook our food.  Making life livable.  And enjoyable.  When we pan-fry we use conduction heating.  Transferring the heat from the burner to the pan to the food.  When we bake we use convection heating.  Transferring the heat from the burner to heat the air in the oven.  Which heats our food.  When we use the broiler we use radiation heating.  Using electric heating elements that glow red-hot, radiating energy into the food underneath them.  A convection oven adds a fan to an oven.  To blow heated air around our food.  Decreasing cooking time.

There’s one other cooking method.  One that is very common in many restaurants.  And in most homes.  But real chefs rarely use this method.  Microwaving.  With a microwave oven.  They’re great, convenient and fast but fine cooking isn’t about speed.  It’s about layering flavors and seasoning.  Which takes time.  Which you don’t get a lot of when a microwave begins vibrating the atoms in the water molecules in your food.   Which is how microwaves cook.  Cooking by vibrating atoms in your food brings temperatures up to serving temperatures.  Unlike conduction heating such as in pan-frying where we bring much higher temperatures into contact with our food.  Allowing us to sear beef and caramelize onions.  Something you can’t do in a microwave oven.  Which is why real chefs don’t use them.

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Trucks, Trains, Ships and Planes

Posted by PITHOCRATES - August 21st, 2013

Technology 101

Big Over-the-Road Tractor Trailer Trucks have Big Wheels so they can have Big Brakes

If you buy a big boat chances are you have a truck or a big SUV to pull it.  For rarely do you see a small car pulling a large boat.  Have you ever wondered why?  A small car can easily pull a large boat on a level (or a near level) surface.  That’s not the problem.  The problem is stopping once it gets moving.  For that is a lot of mass.  Creating a lot of kinetic energy (one half of the mass times velocity squared).  Which is dissipated as heat as brake shoes or pads rub against the wheels.  This is why you need a big truck or SUV to pull a boat.  So you can stop it once it gets moving.

Big trucks and big SUVs have big wheels and big brakes.  Large areas where brake pads/shoes press against a rotating wheel.  All of which is heavy duty equipment.  That can grab onto to those wheels and slow them down.  Converting that kinetic energy into heat.  This is why the big over-the-road tractor trailer trucks have big wheels.  So they can have big enough brakes to stop that huge mass once it gets moving.  Without the brakes turning white hot and melting.  Properly equipped trucks can carry great loads.  Moving freight safely across our highways and byways.  But there is a limit to what they can carry.  Too much weight spread between too few axles will pound the road apart.  Which is why the state police weighs our trucks.  To make sure they have enough axles supporting the load they’re carrying.  So they don’t break up our roads.  And that they can safely stop.

It’s a little different with trains.  All train cars have a fixed number of axles.  But you will notice the size of the cars differ.  Big oversized boxcars carry a lot of freight.  But it’s more big than heavy.  Heavy freight, on the other hand, like coal, you will see in smaller cars.  So the weight they carry doesn’t exceed the permissible weight/axle.  If you ever sat at a railroad crossing as a train passed you’ve probably noticed that the rail moves as the train travels across.  Watch a section of rail the next time you’re stopped by a train.  And you will see the rail sink a little beneath the axle as it passes over.

If a Ship is Watertight and Properly Balanced it can be covered in Green Water and Rise back to the Surface

So the various sizes of train cars (i.e., rolling stock) keeps each car from being overloaded.  Unlike a truck.  Steel haulers and gravel trains (i.e., dump trucks) have numerous axles beneath the load they’re carrying.  But these axles are retractable.  For the more wheels in contact with the road the more fuel is needed to overcome the friction between the tires and the road.  And the more tires in contact with the road the more tire wear there is.  Tires and fuel are expensive.  So truckers like to have as few tires in contact with the road as possible.  When they’re running empty they will have as many of these wheels retracted up as possible.  Something you can’t do with a train.

That said, a train’s weight is critical for the safe operation of a train.  In particular, stopping a train.  The longer a train is the more distance it takes to stop.  It is hard to overload a particular car in the string of cars (i.e., consist) but the total weight tells engineers how fast they can go.  How much they must slow down for curves.  How much distance they need to bring a train to a stop.  And how many handbrakes to set to keep the train from rolling away after the pressure bleeds out of the train line (i.e., the air brakes).  You do this right and it’s safe sailing over the rails.  Ships, on the other hand, have other concerns when it comes to weight.

Ships float.  Because of buoyancy.  The weight of the load presses down on the water while the surface of the water presses back against the ship.  But where you place that weight in a ship makes a big difference.  For a ship needs to maintain a certain amount of freeboard.  The distance between the surface of the water and the deck.  Waves toss ships up and down.  At best you just want water spray splashing onto your deck.  At worst you get solid water (i.e., green water).  If a ship is watertight and properly balanced it can be covered in green water and rise back to the surface.  But if a ship is loaded improperly and lists to one side or is low in the bow it reduces freeboard.  Increases green water.  And makes it less likely to be able to safely weather bad seas.  The SS Edmund Fitzgerald sank in 1975 while crossing Lake Superior in one of the worst storms ever.  She was taking on water.  Increasing her weight and lowering her into the water.  Losing freeboard.  Had increasing amounts of green water across her deck.  To the point that a couple of monster waves crashed over her and submerged her and she never returned to the surface.  It happened so fast that the crew was unable to give out a distress signal.  And as she disappeared below the surface her engine was still turning the propeller.  Driving her into the bottom of the lake.  Breaking the ship in two.  And the torque of the spinning propeller twisting the stern upside down.

Airplanes are the only Mode of Transportation that has two Systems to Carry their Load

One of the worst maritime disasters on the Great Lakes was the sinking of the SS Eastland.  Resulting in the largest loss of life in a shipwreck on the Great Lakes.  In total 844 passengers and crew died.  Was this in a storm like the SS Edmund Fitzgerald?  No.  The SS Eastland was tied to the dock on the Chicago River.  The passengers all went over to one side of the ship.  And the mass of people on one side of the ship caused the ship to capsize.  While tied to the dock.  On the Chicago River.  Because of this shift in weight.  Which can have catastrophic results.  As it can on airplanes.  There’s a sad YouTube video of a cargo 747 taking off.  You then see the nose go up and the plane fall out of the sky.  Probably because the weight slid backwards in the plane.  Shifting the center of gravity.  Causing the nose of the plane to pitch up.  Which disrupted the airflow over the wings.  Causing them to stall.  And with no lift the plane just fell out of the sky.

Airplanes are unique in one way.  They are the only mode of transportation that has two systems to carry their weight.  On the ground the landing gear carries the load.  In the air the wings carry the load.  Which makes taking off and landing the most dangerous parts of flying.  Because a plane has to accelerate rapidly down the runway so the wings begin producing lift.  Once they do the weight of the aircraft begins to transfer from the landing gear to the wings.  Allowing greater speeds.  However, if something goes wrong that interferes with the wings producing lift the wings will be unable to carry the weight of the plane.  And it will fall out of the sky.  Back onto the landing gear.  But once the plane leaves the runway there is nothing the landing gear can gently settle on.  And with no altitude to turn or to glide back to a runway the plane will fall out of the sky wherever it is.  Often with catastrophic results.

A plane has a lot of mass.  And a lot of velocity.  Giving it great kinetic energy.  It takes long runways to travel fast enough to transfer the weight of the aircraft from the landing gear to the wings.  And it takes a long, shallow approach to land an airplane.  So the wheels touch down gently while slowly picking up the weight of the aircraft as the wings lose lift.  And it takes a long runway to slow the plane down to a stop.  Using reverse thrusters to convert that kinetic energy into heat.  Sometimes even running out of runway before bringing the plane to a stop.  No other mode of transportation has this additional complication of travelling.  Transferring the weight from one system to another.  The most dangerous part of flying.  Yet despite this very dangerous transformation flying is the safest mode of traveling.  Because the majority of flying is up in the air in miles of emptiness.  Where if something happens a skilled pilot has time to regain control of the aircraft.  And bring it down safely.

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Study finds Coal cuts Lives by 5 Years for some who wouldn’t have Survived Childhood if it weren’t for Coal

Posted by PITHOCRATES - July 13th, 2013

Week in Review

Early man did not have a long life expectancy.  Thanks to infectious disease and poor (or nonexistent) medical care people who got sick or injured often died.  Unhygienic living spread communicable diseases which killed large numbers in the community.  The lack of fuel to heat your home or cook your food exposed people to the elements and food-borne bacteria.  Causing illnesses that went untreated and added to the death toll.  And a high infant mortality rates brought down the average lifespan further.

There were a lot of old people in their 70s throughout history.  But go back a couple of centuries so many children didn’t survive their childhood that the average lifespan was in the 30s.  But thanks to the modern world of energy and medicine our life expectancies have never been higher.  Even though coal is taking some years off the additional years it gave some (see Burning Heating Coal Cuts Lives by 5 Years in China, Study Finds by Daryl Loo posted 7/9/2013 on Bloomberg).

People in northern China may be dying five years sooner than expected because of diseases caused by air pollution, an unintended result of a decades-old policy providing free coal for heat, a study found.

Coal burning leading to heart disease, stroke, lung cancer and respiratory illnesses may cause the 500 million Chinese living north of the Huai River — a rough line dividing the country’s north and south — to lose an aggregate 2.5 billion years of life expectancy, according to the research published in the Proceedings of the National Academy of Sciences today.

The government gave free heating coal for people living north of the Huai River over a period of central planning from 1950 to 1980, and such indoor systems remain common today, the study showed. Burning coal in boilers is linked to the release of particulate matter that can be extremely harmful to humans, raising health costs and suggesting a move away from using fossil fuels would be attractive, according to Michael Greenstone, one of four authors of the study.

If the government took away fuel to heat and cook with how would that impact their life expectancies?

Yes, it’s sad that breathing particulate matter can remove 5 years of your life.  But how many more years did these people live because of coal?  They had to stay warm somehow.  And they needed to cook their food with something.  If they didn’t have coal these people would have been collecting firewood year round and burning that inside of their homes.  Releasing particulate matter into their homes anyway.  Only with a rise in lost appendages from swinging an axe.  More infected wounds from axe slips.  And they’d have rodents living in their wood piles.  Bringing disease into their homes.  Carried by the fleas on these rodents.

Coal may be taking 5 years away these people.  But they may be taking these years from a person who might not have survived his or her childhood if it weren’t for coal making their home a better place to live in.  It’s time we stop seeing only the bad that coal does.  And start recognizing the good that coal does.  For when it comes to human existence the good of coal far outweighs the bad.  For look where coal has taken us.  To the highest life expectancies in our history.  And it is still making our world a better and healthier place by creating electric power.  The essential ingredient in making the best medical care possible.  Thank you, coal.  Some of us appreciate the good that you do.

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Phase Transition, Expansion Valve, Evaporator, Compressor, Condenser and Air Conditioning

Posted by PITHOCRATES - April 3rd, 2013

Technology 101

We can use Volume, Pressure and Temperature to change Water from a Liquid to a Gas and back Again

Liquids and gasses can do a lot of work for us.  If we can control three variables.  Volume.  Pressure.  And temperature.  For example, internal combustion engines work best when hot.  But excessive heat levels can damage the engine.  So we use a special anti-freeze/anti-boil liquid in the cooling system.  A pump circulates this liquid through the engine where it absorbs some of the excess heat of combustion that isn’t used in pushing the piston.  After leaving the engine it flows through a radiator.  Air blows across tubes in the radiator cooling this liquid.  Ejecting some of the heat of combustion into the atmosphere.  Lowering the temperature of the cooling liquid so it can flow through the engine again and absorb more heat.

Our first cars used alcohol in the winter for a lower freezing point.  So this liquid didn’t freeze in the engine and crack the block.  Letting the coolant flow out.  And with no cooling available the excessive heat levels would damage the engine.  In the summer time we used plain water in the cooling system.  And kept the cooling system sealed and under high pressure to prevent the water from boiling into steam.  But the high pressure often caused a hose or a radiator cap to fail.  Releasing the pressure.  And letting the cooling water boil out leaving the engine unsafe to operate.

If this happened on a hot summer’s day and you got a tow to a gas station you may have sat there waiting for them to complete the repairs.  Sipping on a cool bottle of soda from a refrigerated soda machine.  Soon drops of water would condense onto your cold bottle.  The cold bottle cooled the water in gas form (the humidity in the air) and turned it back into a liquid.  So in these examples we see how we were able to use pressure to keep water a liquid.  And how removing heat from water as a gas changed it back into a liquid.  This phase transition of a material has some very useful applications.

The High-Pressure Refrigerant Liquid from the Condenser loses Pressure going through the Expansion Valve

The phase transition between a liquid and a gas are particularly useful.  Because we can move liquids and gases in pipes and tubing.  Which allows us to take advantage of evaporation (going from a liquid to a gas) in one area.  While taking advantage of condensation (going from a gas to a liquid) in another area.  By changing pressure and volume we can absorb heat during evaporation.  And release heat during condensation.  Allowing us to absorb heat inside a building with evaporation.  And release that heat outdoors with condensation.  All we need are a few additional components and we have air conditioning.  An expansion valve.  An evaporator.  A compressor.  A condenser.  A couple of fans.  And some miscellaneous control components.

We install the expansion valve and the evaporator inside our house.  Often installed inside the furnace.  And the compressor and the condenser outside of the house.  We interconnect the indoor and the outdoor units with tubing.  Inside this tubing is a refrigerant.  Which is a substance that transitions from liquid to a gas and back again at relatively low temperatures.  As the refrigerant moves from the evaporator to the condenser it is a gas.  As it moves from the condenser to the evaporator it is a liquid.  The transition between these stages occurs at the evaporator and the condenser.

The refrigerant leaves the condenser as a liquid under high pressure.  As it passes through the expansion valve the pressure drops.  By restricting the flow of the liquid refrigerant.  Think of a faucet at a kitchen sink.  If you open it all the way the water flowing in and the water flowing out are almost equal.  But if we just open the faucet a little we get only a small trickle of water out of the faucet.  And a pressure drop across the valve.  With the full force of city water pressure pushing to get out of the faucet.  And a low pressure trickle coming out of the faucet.

As the Warm Air blows across the Evaporator Coil any Humidity in the Air will condense on the Coil

As the liquid leaves the expansion valve at a lower pressure it enters the evaporator coil.  A fan blows the warm air inside of the house through the evaporator coil.  The heat in this air raises the temperature of the refrigerant.  And because of the lower pressure this heat readily boils the liquid into a gas.  That is, it evaporates.  Absorbing heat from the warm air as it does.  Cooling the air.  Which the fan blows throughout the ductwork of the house.

As the gas leaves the evaporator it travels through a tube to the condenser unit outside.  And enters a compressor.  Where an electric motor spins a crankshaft.  Attached to the crankshaft are two pistons.  As a piston moves down it pulls low pressure gas into the cylinder.  As the piston moves up it compresses this gas into a higher pressure.  As the pressure rises it applies more pressure on the spring holding the discharge valve closed.  When the pressure is great enough it forces open the valve.  And sends the high-pressure gas to the condenser coil.  Where a fan blows air through it lowering the temperature of the high pressure gas enough to return it to a liquid.  As it does it releases heat from the refrigerant into the atmosphere.  Cooling the refrigerant.  As the liquid leaves the condenser it flows to the expansion valve to repeat the cycle.  Over and over again until the temperature inside the house falls below the setting on the thermostat.  Shutting the system down.  Until the temperature rises high enough to turn it back on.  A window air conditioner works the same way.  Only they package all of the components together into one unit.

There is one other liquid in an air conditioning system.  Water.  As the warm air blows across the evaporator coil any humidity in the air will condense on the coil.  Like on a cold bottle of soda on a hot summer day.  As this water condenses on the evaporator coil is eventually drips off into a pan with a drain line.  If the evaporator is in the furnace this line will likely run to a sewer.  If the evaporator is in the attic this line will run to the exterior of the house.  Perhaps draining into a gutter.  If it’s a window unit this line runs to the exterior side of the unit.  These simple components working together give us a cool and dehumidified house to live in.  No matter how hot and humid it gets outside.

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Air Handling Unit, Outside Air, Exhaust Air, Return Air and Energy Recovery Unit

Posted by PITHOCRATES - March 27th, 2013

Technology 101

Things that Absorb Energy can Cool Things Down and Things that Radiate Energy can Warm Things Up

When two different temperatures come into contact with each other they try to reach equilibrium.  The warmer temperature cools down.  And the cooler temperature warms up.  If you drop some ice cubes into a glass of soda at room temperature the warm soda cools down.  The ice cubes warm up.  And melt.  When there is no more ice to melt the temperature of the soda rises again.  Until it reaches the ambient room temperature.  The normal unheated or un-cooled temperature in the surrounding space.  As the soda and the air in the room reach equilibrium.

When two temperatures come into contact with each other what happens depends on the available energy.  Higher temperatures have more energy.  Lower temperatures have less energy.  For heat is energy.  Things that absorb energy can cool things down.  Things that radiate energy can warm things up.  And this is the basis of our heating and cooling systems in our buildings and homes.

Boilers burn fuel to heat water.  A furnace burns fuel to heat air.  The heated water temperature and heated air temperature is warmer than the temperature you set on your thermostat.  When this very hot water/air circulates through a house or building it comes into contact with the cooler air.  As they come into contact with each other they bring the air in the space up to a comfortable room temperature.  Above the unheated ambient temperature.  But below the very hot temperature of the heating hot water or heated air temperature.

Heating and Cooling Buildings consume up to Half of all Energy on the Planet

Large buildings have air handling units (AHU) that ventilate, heat and cool the building’s air.  They’re big boxes (some big enough for grown men to walk in) with filter sections to clean the air.  Coil sections that heat or cool the air as it blows through these coils.  A supply and a return fan to blow air into the building via a network of air ducts.  And to suck air out of the building through another network of air ducts.  And a series of dampers (outside air, exhaust air and return air).

To keep the air quality suitable for humans we have to exhaust the breath we exhale from the building.  And replace it with fresh air from outside of the building.  This is what the dampers are for.  The amount they open and close adjusts the amount of outside air the AHU pulls into the building.  The amount of the air it exhausts from the building.  And the amount of air it recirculates within the building.  Elaborate computer control systems carefully adjust these damper positions.  For the amount of moving air has to balance.  If you exhaust less you have to recirculate more.  Otherwise you may have dangerous high pressures build up that can damage the system.

It takes a lot of energy to do this.  Buildings consume up to half of all energy on the planet.  And heating and cooling buildings is a big reason why.  Because it take a lot of energy to raise or lower a building’s air temperature.  And keeping the air safe for humans to breathe adds to that large energy consumption.  If you stand outside next to an exhaust air damper you can understand why.  If it’s winter time the exhausted air is toasty warm.  If it’s summer time the exhausted air is refreshingly cool.

An Energy Recovery Wheel is a Circular Honeycomb Matrix that Rotates through both the Outside & Exhaust Air Ducts

In the winter large volumes of gas fire boilers to heat water.  Electric water pumps send this water throughout the building.  Into baseboard convection heaters under exterior windows to wash this cold glass with warm air.  And into the heating coils on AHUs.  Powerful electric supply and return fans blow air through those heating coils and throughout the building.  After traveling through the supply air ductwork, out of the supply air ductwork and into the open air, back into the return air ductwork and back to the AHU much of this air exhausts out of the building.  That returning air is not as warm as the supply air coming off of the heating coil.  But it is still warm.  And exhausting it out of the building dumps a lot of energy out of the building that requires new energy to heat very cold outside air to replace it.  The more air you recirculate the less money it costs to heat the building.  But you can only recirculate air so long before you compromise the quality of indoor air.  So you eventually have to exhaust heated air and pull in more unheated outside air.

Enter the heat recovery unit.  Or energy recovery unit.  There are different names.  And different technologies.  But they do pretty much the same thing.  They recover the energy in the exhaust air BEFORE it leaves the building.  And transfers it to the outside air coming into the building.  To understand how this works think of the outside air duct and the exhaust air duct running side by side.  With the air moving in opposite directions.  Like a two-lane highway.  These sections of duct run between the AHU and the outside air and exhaust air dampers.  It is in this section of ductwork where we put an energy recovery unit.  Like an energy recovery wheel.  A circular honeycomb matrix that slowly rotates through both ducts.  Half of the wheel is in the outside air duct.  Half of the wheel is in the exhaust air duct.  As exhaust air blows through the honeycomb matrix it absorbs heat (i.e., energy) from the exhaust air stream.  As that section of the wheel rotates into the outside air duct the unheated outside air blows through the now warm honeycomb matrix.  Where the unheated air absorbs the energy from the wheel.  Warming it slightly so the AHU doesn’t have use as much energy to heat outside air.  It works similarly with air conditioned air.

Many of us no doubt heard our mother yell, “Shut the door.  You’re letting all of the heat out.”  For whenever you open a door heated air will vent out and cold air will migrate in.  Making it cooler for awhile until the furnace can bring the temperature back up.  It’s similar with commercial buildings.  Which is why a lot of them have revolving doors.  So there is always an airlock between the heated/cooled air inside and the air outside.  But engineers do something else to keep the cold/hot/humid air outside when people open doors.  They design the AHU control system to maintain a higher pressure inside the building than there is outside of the building.  So when people open doors air blows out.  Not in.  This keeps cold air from leaking into the building.  Allowing people to work comfortably near these doors without getting a cold blast of air whenever they open.  It allows people to work along exterior windows and walls without feeling any cold drafts.  And it also helps to keep any bad smells from outside getting into the building.

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Fire, Oil Lamp, Candle, Wicks, Gas Lights, Incandescence, Incandescent Light Bulb, Fluorescence and Compact Fluorescent Lamp

Posted by PITHOCRATES - February 20th, 2013

Technology 101

(Originally published March 28th, 2012)

A Lit Match heats the Fuel Absorbed into a Wick, Vaporizes it, Mixes it with Oxygen and Ignites It

Fire changed the world.  From when Homo erectus first captured it.  Around 600,000 BC.  In China.  They saw it.  Maybe following a lightning strike.  Seeing it around volcanic activity.  Perhaps a burning natural gas vent.  Whatever.  They saw fire.  Approached it.  And learned not to fear it.  How to add fuel to it.  To transfer it to another fuel source.  To carry it.  They couldn’t create fire.  But they could manage it.  And use it.  It was warm.  And bright.  So they brought it indoors.  To light up their caves.  Scare the predators out.  To use it to heat.  And to cook.  Taking a giant leap forward for mankind.

When man moved into man-made dwellings they brought fire with them.  At first a one-room structure with a fire in the center of it.  And a hole in the roof above it.  Where everyone gathered around to eat.  Stay warm.  Sleep.  Even to make babies.  As there wasn’t a lot of modesty back then.  Not that anyone complained much.  What was a little romance next to you when you were living in a room full of smoke, soot and ash?  Fireplaces and chimneys changed all that.  Back to back fireplaces could share a chimney.  Providing more heat and light.  Less smoke and ash.  And a little privacy.  Where the family could be in one room eating, staying warm, reading, playing games and sleeping.  While the grownups could make babies in the other room.

As we advanced so did our literacy.  After a hard day’s work we went inside.  After the sun set.  To read.  Write letters.  Do some paperwork for the business.  Write an opera.  Whatever.  Even during the summer time.  When it was warm.  And we didn’t have a large fire burning in the fireplace.  But we could still see to read and write.  Thanks to candles.  And oil lamps.  One using a liquid fuel.  One using a solid fuel.  But they both operate basically the same.  The wick draws liquid (or liquefied) fuel via capillary action.  Where a porous substance placed into contact with a liquid will absorb that liquid.  Like a paper towel or a sponge.  When you place a lit match into contact with the wick it heats the fuel absorbed into the wick and vaporizes it.  Mixing it with the oxygen in the air.  And ignites it.  Creating a flame.  The candle works the same way only starting with a solid fuel.  The match melts the top of this fuel and liquefies it.  Then it works the same way as an oil lamp.  With the heat of the flame melting the solid fuel to continue the process.

Placing a Mantle over a Flame created Light through Incandescence (when a Heated Object emits Visible Light)

Two popular oils were olive oil and whale oil.  Beeswax and tallow were common solid fuels.  Candles set the standard for noting lighting intensity.  One candle flame produced one candlepower.  Or ‘candela’ as we refer to it now.   (Which equals about 13 lumens – the amount of light emitted by a source).  If you placed multiple candles into a candelabrum you could increase the lighting intensity.  Three candles gave you 3 candela of light to read or write by.  A chandelier with numerous candles suspended from the ceiling could illuminate a room.  This artificial light shortened the nights.  And increased the working day.  In the 19th century John D. Rockefeller gave the world a new fuel for their oil lamps.  Kerosene.  Refined from petroleum oil.  And saved the whales.  By providing a more plentiful fuel.  At cheaper prices.

By shortening the nights we also made our streets safer.  Some cities passed laws for people living on streets to hang a lamp or two outside.  To light up the street.  Which did indeed help make the streets brighter.  And safer.  To improve on this street lighting idea required a new fuel.  Something in a gas form.  Something that you could pump into a piping system and route to the new street lamps.  A gas kept under a slight pressure so that it would flow up the lamp post.  Where you opened the gas spigot at night.  And lit the gas.  And the lamp glowed until you turned off the gas spigot in the morning.  Another advantage of gas lighting was it didn’t need wicks.  Just a nozzle for the gas to come out of where you could light it.  So there was no need to refuel or to replace the wicks.  Thus allowing them to stay lit for long periods with minimum maintenance.  We later put a mantle over the flame.  And used the flame to heat the mantle which then glowed bright white.  A mantle is like a little bag that fits over the flame made out of a heat resistant fabric.  Infused into the fabric are things that glow white when heated.  Rare-earth metallic salts.  Which change into solid oxides when heated to incandescence (when a heated object emits visible light).

One of the first gases we used was coal-gas.  Discovered in coal mines.  And then produced outside of a coal mine from mined coal.  It worked great.  But when it burned it emitted carbon.  Like all these open flames did.  Which is a bit of a drawback for indoor use.  Filling your house up with smoke.  And soot.  Not to mention that other thing.  Filling up your house with open flames.  Which can be very dangerous indoors.  So we enclosed some of these flames.  Placing them in a glass chimney.  Or glass boxes.  As in street lighting.  Enclosing the flame completely (but with enough venting to sustain the flame) to prevent the rain form putting it out.  This glass, though, blackened from all that carbon and soot.  Adding additional maintenance.  But at least they were safer.   And less of a fire hazard.  Well, at least less of one type of fire hazard.  From the flame.  But there was another hazard.  We were piping gas everywhere.  Outside.  Into buildings.  Even into our homes.  Where it wasn’t uncommon for this gas to go boom.  Particularly dangerous were theatres.  Where they turned on the gas.  And then went to each gas nozzle with an open fire on a stick to light them.  And if they didn’t move quickly enough the theatre filled with a lot of gas.  An enclosed space filled with a lot of gas with someone walking around with an open fire on a stick.  Never a good thing.

Fluorescent Lighting is the Lighting of Choice in Commercial, Professional and Institutional Buildings

Thomas Edison fixed all of these problems.  By finding another way to produce incandescence. By running an electrical current through a filament inside a sealed bulb.  The current heated the filament to incandescence.  Creating a lot of heat.  And some visible light.  First filaments were carbon based.  Then tungsten became the filament of choice.  Because they lasted longer.  At first the bulbs contained a vacuum.  But they found later that a noble gas prevented the blackening of the bulb.  The incandescent light bulb ended the era of gas lighting.  For it was safer.  Required less maintenance.  And was much easier to operate.  All you had to do was flick a switch.  As amazing as the incandescent light bulb was it had one big drawback.  Especially when we use a lot of them indoors.  That heat.  As the filament produced far more heat than light.  Which made hot buildings hotter.  And made air conditioners work harder getting that heat out of the building.  Enter the fluorescent lamp.

If phosphor absorbs invisible short-wave ultraviolet radiation it will fluoresce.  And emit long-wave visible light.  But not through incandescence.  But by luminescence.  Instead of using heat to produce light this process uses cooler electromagnetic radiation.  Which forms the basis of the fluorescent lamp.  A gas-discharge lamp.  The most common being the 4-foot tube you see in office buildings.  This tube has an electrode at each end.  Contains a noble gas (outer shell of valence electrons are full and not chemically reactive or electrically conductive) at a low pressure.  And a little bit of mercury.  When we turn on the lamp we create an electric field between the electrodes.  As it grows in intensity it eventually pulls electrons out of their valence shell ionizing the gas into an electrically conductive plasma.  This creates an arc between the electrodes.  This charged plasma field excites the mercury.  Which produces the invisible short-wave ultraviolet radiation that the phosphor absorbs.  Causing fluorescence.

One candle produces about 13 lumens of light.  Barely enough to read and write by.  Whereas a 100W incandescent light bulb produces about 1,600 lumens.  The equivalent of 123 candles.  In other words, one incandescent lamp produces the same amount of light as a 123-candle chandelier.  Without the smoke, soot or fire hazard.  And the compact fluorescent lamp improves on this.  For a 26W compact fluorescent lamp can produce the lumen output of a 100W incandescent light bulb.  A one-to-one tradeoff on lighting output.  At a quarter of the power consumption.  And producing less heat due to creating light from fluorescence instead of incandescence.  Making fluorescent lighting the lighting of choice in commercial, professional and institutional buildings.  And any other air conditioned space with large lighting loads.

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