Solar powered heater

[tekplague]

My engineering class asignment is to build a solar heater to cook a hot dog internal temperature to 150 degrees F. Everyone is looking to build some kind of light reflecting setup to heat the hot dog but i was wondering if it would be more efficient to use a solar panel and build a simple electric heater. I know very little of circuits or the power required to heat anything or even how to go about making a heater.

Does anyone know if this is possible?
If its possible how would i make the heater most efficently to heat a hot dog?

Thanks very much
Justin

 

[Valence_4]

It doesn't worth it at all.

Photovoltaic panels are VERY expensive (over 5 $ per watt) and have fairly low energetic efficiency. And if it was not enough, all heating apparatus require a lot of power. Soto build a small 500 watt heater, you would require a 2000-2500 $ panel array. In fact, photovoltaic panels are used in conjunction with high efficiency battery chargers and high efficiency DC-DC or DC-AC converters to power energy efficient devices which DO NOT include heaters !

Reflective solar heaters on theur side, are far more energy efficient and can be built from inexpensive materials.

 

[Willbe]

Everyone is looking to build some kind of light reflecting setup to heat the hot dog but i was wondering if it would be more efficient to use a solar panel and build a simple electric heater.
Does anyone know if this is possible?
If its possible how would i make the heater most efficently to heat a hot dog?

They get 60w/sq. ft., you get 4w/sq.ft.

 

[tekplague]

Thanks for the answers, I figured it wouldnt be worth it since i couldnt find anything about this on the internet but figured id ask anyway.

Back to the drawing board.

PS: how many watts does a AA battery put out? I know if you connect a wire to both sides directly its so hot you cant hold it, this is what i was thinking with the solar cooker, mayby running wires through the inside to heat it.

How do you make a heater in general though, just wondering?

 

[blueroomelectronics]

Not enough to cook a hot dog. Google Solar hot dog cooker?
**broken link removed**
**broken link removed**

 

[tekplague]

I know you can cook it by reflecting sunlight, my question here was if it was more efficient to use solar panels to run an electric heater, thats what i couldnt find on google.

 

[blueroomelectronics]

Nope reflecting sunlight is still more efficient than current tech solar panels.

 

[audioguru]

One AA size Ni-MH rechargeable cell is rated at 1.2V and 2500mAh. It puts out 3W for 1 hour. It might have an output of 4W for half an hour or 5W for 1/4 hour.

 

[Nigel Goodwin]

I know you can cook it by reflecting sunlight, my question here was if it was more efficient to use solar panels to run an electric heater, thats what i couldnt find on google.

As you've already been told, solar panels are FAR less efficient - and you probably couldn't afford enough of them to cook a hot dog (I couldn't).

 

[stevez]

Unless the rules of the game prohibit storage you might use a few solar cells to charge a battery - so there's enough power to do the job. You'd need to run some experiments to determine how much power to cook your hot dog - but once you've done that you can work backward.

Even before you do the experiments you can estimate the amount of power required to heat the hot dog from whatever the starting point is to 150 deg F. I know there is data available on energy required to cool/freeze various foods.

An extremely crude place to begin would be to measure the power (current and time) required to cook a hot dog by conventional means - a burner on the oven, a countertop toaster oven. Those are inefficient methods by any measure but they give you an upper limit. Maybe your rules don't limit you to a battery, inverter and toaster oven.

 

[KMoffett]

Not enough to cook a hot dog. Google Solar hot dog cooker?
**broken link removed**

OK "You showed me yours, so I'll show you mine" **broken link removed**
Left over parts from a bunch of 3' solar collectors I made for a "Physics of Renewable Energy" Lab. The electronics content is the T/C and digital thermometer.

Ken

 

[Willbe]

An extremely crude place to begin would be to measure the power (current and time) required to cook a hot dog

Two common 8d nails, one in each end of the dog, connected to 120v through a current limiting device (a toaster?) and measure the V across and the I through and the time it takes.
Then feed the dog to someone else.

 

[KMoffett]

Did that in college! You don't need a current limiter...hot dogs have a self current-limiting characteristic. As the current heats them they give off steam, drying them out and raising the resistance. Intrinsically safe!...Right?

Ken

 

[stevez]

I do agree with the self limiting though I'd stop short of feeling safe unless I really understood that the conductivity drops enough to prevent a fire. My though is that some part of the hot dog near an electrode gets real dry while the rest remains conductive - the fire starts and as the hot dog further dries it can burn more. Not a big deal in a proper enclosure - but maybe a point worth mentioning to the professor.

 

[audioguru]

Lightning will cook the hot dog much faster.
Use a kite with metal string and a ground rod. Stand back!

 

[KMoffett]

Something beyond two nails and a "suicide cord":

**broken link removed**
64.24 -- Electric hot dog cooker

And a commercial version: **broken link removed**

and a Photovoltaic one: YouTube - Photovoltaic Hotdog Cooker

Ken

 

[blueroomelectronics]

I recall reading the induction cooked dogs taste funny.

 

[Hero999]

A fuse will provide enough protection to prevent a fire.

Electric solar pannels are around 10% efficient, focussing the light directy onto the hot dog is around 80% effieint.

Charging batteries would not help since it would take much longer.

Have you heard about solar powered air conditioning?

**broken link removed**
**broken link removed**

It sounds silly not to use solar power to cool things.

 

[Boncuk]

Get yourself a bunch of magnifying glasses and focus them on the hot dog.
It will be cooked in no time.

Cooking overtime results in charcoal sausages.

 

[Valence_4]

I've seen in the past (many years ago) an electrocution hot-dog cooker. The cooker introduced two conical probes in the ends of the sausage and the whole thing was DIRECTLY fed to a 120 volt source.

You could use a such apparatus to measure the power (V*I) and the tiime it takes to cook the sausage to have a figure of how much power it takes to cook it. However, BEWARE! Since mains power is DIRECTLY applied to the sausage, care must be taken to avoid ANY contact to the sausage while it is energized !

This method has the advantage of being accurate since ALL the power is applied to the sausage itself and to nothing else.

If i remember well, the cooker was made by Amway.

Oops... I just saw that KMoffett sent a link to the "Hot-dogger" by Presto ! That was the thing we used to cook our hot-dogs !