Hello everyone this is my first post please engage in discussion should you have any valid points.
The project i am doing for my hnd electronics is to build a device to melt ice from windscreens remotely. Many factors need to be considered , the reason for my post is to attempt to gain a better understanding of nichrome and also transistors as a temp sensor to control current in the nichrome.
If anyone has practical experience or technical information please do share as all relevant information could be added to my portfolio.
Many thanks
Adrian √

 

build a device to melt ice from windscreens remotely.

what do you mean remotely?
Why wouldn't you just use an off the shelf PID type temp sensor/controller?

 

Googling 'aircraft heated windshield' gets some good stuff including these:
NASA determines power required
How its done in a C130.

'NESA Electropane' gets some more info including a patent.

 

Are you talking abut remote control of a window defroster, so the car is de-icing itself while you're in a nice warm office?

 

what do you mean remotely?
Why wouldn't you just use an off the shelf PID type temp sensor/controller?

Thank you for reply,

The remote activation is required as my concept is to melt ice from a frozen windscreen from home or office.

Due to this being my hnd project im trying to think outside the box and minimise
the parts used while trying to be innovative.

There are several others ways of doing this i have discounted for different reasons.

 

Are you talking abut remote control of a window defroster, so the car is de-icing itself while you're in a nice warm office?

Yes thats exactly it

 

What are you thinking, activating existing heaters, adding some kind of hidden heating elements, or a blanket over the window?

Just trying to get a visual.

I wonder what element these use?

Or heat tape. Some have distributed resistance between conductors.

 

What are you thinking, activating existing heaters, adding some kind of hidden heating elements, or a blanket over the window?

Just trying to get a visual.

I wonder what element these use?

Or heat tape. Some have distributed resistance between conductors.

Thanks for the reply inwo, im thinking of using nichrome ribbon around the perimeter of the windscreen and this will be the heating part of the circuit i really want to use the special properties of this wire to my advantage and with the use of possibly transistors to control the current supplied to the nichrome.

The concept will most likely end as a system motorists could buy and add to any vehicle.

Please ask anything else you feel would help describe my idea as im well aware most of it is rattling around my head at tremendous speed lol

 

That was a very interesting test NASA performed i may be able to work out the watts needed at 0mph by transposing the formula originally used.
Thanks again
Adrian

 

"remote start" systems are already easily available and even built in to many new cars now directly from your smart phone.. not only do they directly address "defrosting" they also heat the interior at the same time..turn on seat heaters,etc...
your about 40 years too late

 

Battery powered heaters are so difficult to implement because heaters take soooo much power. After all, they are 100% inefficient use of power and must not only melt the ice but also heat the windshield from ambient to 32F (0C).

Starting the vehicle and letting the engine heat do the "work" would be much easier. Your system would require either a separate power source (battery packs) or you would run the risk of draining the battery below the point that it could start your car - especially in the cold.

 

Battery powered heaters are so difficult to implement because heaters take soooo much power. After all, they are 100% inefficient use of power and must not only melt the ice but also heat the windshield from ambient to 32F (0C).

Starting the vehicle and letting the engine heat do the "work" would be much easier. Your system would require either a separate power source (battery packs) or you would run the risk of draining the battery below the point that it could start your car - especially in the cold.

Exactly right!

I had a battery operated windshield demister back in the "dark ages",& left it on when I got to work.
(Manufacturers reckoned Australia was "too warm" to supply a heater/demister as standard)

There I sat,in the middle of a huge cold,dark,empty car park,waiting for a workmate to come from home with jumper leads!

 

thanks for replying mcgvr unfortunatley remote starting an engine is illegal in my country, as mentioned there are several ways of solving this problem , however in posting on this form to gain information on the system i plan to assemble . Sorry if this isnt clear from previous posts.

 

I'm trying to minimize the parts used.

A remote control defeats this pretty well.

 

Battery powered heaters are so difficult to implement because heaters take soooo much power. After all, they are 100% inefficient use of power and must not only melt the ice but also heat the windshield from ambient to 32F (0C).

Starting the vehicle and letting the engine heat do the "work" would be much easier. Your system would require either a separate power source (battery packs) or you would run the risk of draining the battery below the point that it could start your car - especially in the cold.

This was my intial idea to solve the problem however the ideling of an engine is illegal in scotland and could be seen as hazardous to the enviroment.

I fully understand why you would try to encourage me not to use the battery at risk of draining it.

This being said i belive with the right combination of nichrome wire , transistor and the 12v supply should be able to at least clear enough of the glass to be able to see out of.

Many thanks for your reply

 

Please ask me any questions you want regarding this project however i am well aware that remote start systems are available . This is a project i am doing as the problem effects me for 4 months of the year. Also my initail post clearly states " the reason for my post is to attempt to gain a better understanding of nichrome and also transistors as a temp sensor to control current in the nichrome"

 

#12 the remote control i intend to use is a bluetooth enabled phone most modern phones have bluetooth now so the transmitter part of the circuit is something already carried by most motorists.

I understand this seems a very simple idea or problem to solve but the difficulties i am looking for help and advive with are relating to nichrome or even melting ice with current.

Thanks again for the replies

 

Have you arrived at an estimate of the amount of heat required in B.T.U.s or watt seconds? I'm getting a feeling for 540 watts. That's 45 amps at 12 volts. That's half a car battery worth of power per hour except that cold makes batteries less able to produce energy.

 

This was my intial idea to solve the problem however the ideling of an engine is illegal in scotland and could be seen as hazardous to the enviroment.

I've come to find out that is a law in some of the states here too sadly.. but most are written to exclude auto start systems.

 

Have you arrived at an estimate of the amount of heat required in B.T.U.s or watt seconds? I'm getting a feeling for 540 watts. That's 45 amps at 12 volts. That's half a car battery worth of power per hour except that cold makes batteries less able to produce energy.

That is one of reasons that such a system always burn fuel from the fuel tank. That again heat up the cooling agent.
To the OP see page 5 in this document for a short and simple explanation on how such systems work http://www.webasto.com/fileadmin/we.../car/brochure/car-parking-heater-brochure.pdf