Automotive Tools

Speed Air

What is the difference between an Inverter and Normal Fixed speed air conditioner?

We've all seen them - the supermarket split type air conditioners - at what seems like an incredible price.

But the old adage still remains true - "You get what you pay for".

A good analogy for this is the cheap computer printer. It seems like such great value until you come to replace the ink cartridge - which often costs more than the printer itself!

Don't get me wrong - we still happily sell the cheaper units - but it's only responsible of us to inform you of the advantages and disadvantages of using price as your number one criteria for choosing a unit.

We prefer to substitute the word "price" with "value for money" - and this is when the "Inverter" type air conditioner suddenly starts looking attractive.

To put it simply - Inverters cost more money to buy, but are more efficient to run, which saves you money on your energy costs, which makes them better "value for money" over all.

Another advantage to Inverters is they are quieter than conventional "Fixed Speed" air con units due to the way they achieve their efficiency.

So whats the Difference?

What is a Fixed Speed Unit?

This unit only has a single speed compressor motor that is either on or off.

It works similar to a fan heater that switches off when the desired temperature is reached and on again when the temperature drops to a set level.

What does Inverter Mean?
Inverter technology uses a variable speed compressor motor similar to a car. It simply slows down and speeds up as needed to hold a selected comfort setting.

Inverter technology provides a more precise room temperature without the temperature fluctuations of fixed speed systems.
Inverter versus Standard:

# Inverter units are Approximately 30% more efficient than fixed speed units.

# Inverter units reach the set room temperature quicker.

# The speed control of the outdoor unit also means quieter operation, this is important especially at night in residential areas.

Inverter Systems

* Increased output to achieve set temperature faster.
* Then varies the output to maintain a constant room temperature.

Fixed Speed Type

* Slowly gets to temperature as output rating is fixed.
* Then turns on and off to maintain room temperature.

But?

There's a but
To get these efficiency gains it is important to use the air conditioner as it is intended:

* the unit has to be sized right for the room you are heating/cooling
* it is best to run the unit continuously and set for the desired room temperature (i.e. such as 21 Celcius) and not at a full setting for heating or cooling (as most people do)
* and of course - a well insulated, low-thermal mass villa helps too...

About the Author

I am the co owner of Penguin Air Con, who deal with air conditioning, solar heating and solar panels in the Algarve. http://www.penguinaircon.com

Do all sounds travel at the same speed in air?

"All sounds travel at the same speed in air".

This was a statement in my science textbook. However, if the frequency and wavelengths of sound waves vary (e.g. high freq. waves have short wavelengths and vice versa), how could it be that all sounds travel at the same speed in air? If the formula is 'speed = freq. x wavelength', does that mean all sound waves have the same frequency and wavelength?

thanks for the insight
=)

P.S. Please use simple terminology, as i am new to this topic. Thanks once again.

All sounds travel at the same speed in air".

This was a statement in my science textbook. However, if the frequency and wavelengths of sound waves vary (e.g. high freq. waves have short wavelengths and vice versa), how could it be that all sounds travel at the same speed in air? If the formula is 'speed = freq. x wavelength', does that mean all sound waves have the same frequency and wavelength?

Frequency tells us the number of waves that pass a specific point each second.

Wave length tells us the length of the wave.

Story time!!
You are sitting at a railroad crossing, watching a train. You see 10 cars pass in front of you in 5 seconds. Each box car is 4 m long.

What is the speed of the train?

Speed = distance ÷ time
Distance = 10 cars * 4 m/car = 40 m
Time = 5 seconds
Speed = 40 ÷ 5 = 8 m/s

How many cars pass in front of you each second?
10 cars ÷ 5 s = 2 cars/s
Frequency = 2 cars/s

The length of 1 car = 4 m
Car length = 4 m/car

Velocity of car = 4 m/car * 2 cars/s = 8 m/s
Velocity = car length * frequency
The equation above is very similar to the wave equation below.
Velocity = wave length * frequency

2nd train passes in front of you. You see 20 cars pass in front of you in 5 seconds. Each box car is 2 m long.

What is the speed of the train?

Speed = distance ÷ time
Distance = 20 cars * 2 m/car = 40 m
Time = 5 seconds
Speed = 40 ÷ 5 = 8 m/s

How many cars pass in front of you each second?
20 cars ÷ 5 s = 4 cars/s
Frequency = 4 cars/s

The length of 1 car = 2 m
Car length = 2 m/car

Velocity of car = 2 m/car * 4 cars/s = 8 m/s

2nd train car length = ½ * 1st train car length
2nd train frequency = 2 * 1st train frequency

2nd train velocity = 2 * 1st train velocity

Now back to WAVES

Wave length = 5 meters per wave
Frequency = 10 Hz
Hz = waves per second

In your Physic’s book, the unit of frequency is s^-1 = 1/s
In your Physic’s book, the unit of wave length is m.

I write the unit of frequency as wave/s
I write the unit of wave length as m/wave
I do this so students will know that 10 WAVES are passing in front of you each second, and know that 5 meters is the length of 1 WAVE.

Velocity = Wave length * frequency
The velocity of sound waves depends on the medium that the sound wave is moving through.

In dry air at 20 °C (68 °F), the speed of sound is 343 m/s

When you play middle C on a piano, the frequency = 262 Hz
The waver length = 1.309 m
343 = 1.309 * 262

When you play middle A above middle C on a piano, the frequency = 440 Hz
The waver length = 0.78 m
343 = 0.78 * 440

If the wave length is short, more waves will pass a specific point each second!!

If the wave length is long, fewer waves will pass a specific point each second!!

If the car length is short, more cars will pass in front of you each second!!

If the car length is long, fewer cars will pass a specific point each second!!

I hope this helps

Speed Air Man--David Belle