Thread: Trying to design a super efficiant heater

Resistive heaters are all 100% efficient. All power is converted to heat. (until they glow...then some is converter to light ) The iInsulating material on the heater affects heat transfer rate, but it's still all heat. The fastest transfer rate is with open nichrome wire elements. In making you incubator more efficient there are two factors: insulation and circulation. Insulation reduces heat loss, and circulation puts the heat where you need it.

Ken

Ken said it right.
You cannot make a more efficient heater; you can make a more efficient chamber.

Disemboweling toasters and many heaters yield nichrome wire. Light bulbs on a dimmer is to consider.

Any mass added in the heat chamber will reduce cycling; be a piece of lead, a potato, or a cup of water.

Miguel

Originally Posted by cbiblis

Here is the thing, correct me if i'm wrong but a ceramic heater it more efficient then a strait nichrome wire due to the storage of heat. I have compared the KWH on a nichrome heater and the KWH on a ceramic heater and the difference was 40% more efficient. This is why i am considering the ceramic resistors instead of the nichrome.

A Watt is a Watt is a Watt... it matters not Watt the heater is made of

Originally Posted by cbiblis

Here is the thing, correct me if i'm wrong but a ceramic heater it more efficient then a strait nichrome wire due to the storage of heat. I have compared the KWH on a nichrome heater and the KWH on a ceramic heater and the difference was 40% more efficient. This is why i am considering the ceramic resistors instead of the nichrome.

Can you post links to where you saw these spec's?

Ken

Originally Posted by dougy83

So what's the heating efficiency of a heat pump then?

The better the pump, the lower it will be - the idea is to pump, not to generate heat.

Originally Posted by cbiblis

Also the idea behind the resistors is to use the insulation to store the heat to reduce cycle times. Do you agree with my assessment?

The idea of an incubator is achieving a very accurate temperature of 37.5deg/C.

Using heaters storing heat (like high power ceramic insulator type resistors) you'll get a temperature overshoot every time heating is disabled (accumulative heating). Depending on the incubator size the temperature increase might get as high as 2deg/C over the desired temperature reducing hatch rate.

Using a microcontroller and software enabling the MCU to look ahaed (tendency) activation of heaters can be interrupted by a using a certain lead time. This lead time will only be valid for a certain temperature difference (between amibient air and incubator air). A better solution is using proportional heater control and probably a long period (1 to 2.5 minutes) integral part.

I have designed an incubator control circuit controlling heat, humidification and egg turner. After some experiments I kicked out the integral part since proportional control suffices with an accuracy of ±0.2deg/C.

Using a triac or SSR to switch on and off the heater shouldn't be a problem. There won't be burnt contacts (like using a relay) and switching is done silently no matter how many cycles you apply.

For comparison look at high quality soldering stations. They cycle like hell and do it for 10 to 15 years without having to replace any part.

Boncuk

Originally Posted by dougy83

So what's the heating efficiency of a heat pump then?

If you look at heat out versus energy in, then a heat pump is always more than 100% efficient.

Deleted by poster (I misspoke).