Input needed.... read this......

[DJ88]

Troy.. It basically works as a heater but through the glass. It also does the reverse and cools. Hard to explain.. umm..

It is two electric plates mounted side by side.. when electricity passes through it in one direction it produces heat. When the current is reversed it cools. I am going to use this for heating and cooling the tank.

In essence it pulls the heat from the tank and releases it to the air. And does the reverse for heating. Voila a heater n chiller in one.. [img]images/smiles/icon_biggrin.gif[/img] I am actually suprised I have never seen one or heard of anyone using one like this.. Great application.

I was thinking about making these and patenting them(the controller) but heck.. I'll share.. Too much work right now to make it quietly.. lol

It is called a Peltier device. It is a Thermoelectric cooler/heater module. A good example of one of these is those car food coolers/heaters you can get from Canadian Tire.

[ 08 November 2001: Message edited by: DJ88 ]

[StirCrazy]

Hi Darren, hey just out of curosity what did you do when you were in the military? I am a stoker.. anyways for the heating / cooling were you thinking of using a peltia type heat sink? I just got one of them plug in coolers for a poresent and that is what they have.. run the power one direction the fins get cold.. the other they get hot.. I think the temp controler is a good idea.. but how about some sort of temp reading display? maby a led out of a old computer to display the numbers?

Steve

[DJ88]

Hey Steve,

NET(A) was my trade. What ships? Gatineau, Ville de Quebec, Annapolis, Calgary and Regina.

You got it.. By reversing the current flow(very low current drawn) you reverse how the transistor works inside. In one direction it pulls heat from the contacted surface, reverse it it puts heat in.

As well I am looking into putting a LCD display on it. showing temp etc.

[ 08 November 2001: Message edited by: DJ88 ]

[Bryan]

Excellent, do you plan on posting a schematic.

For ideas on the wasvemaker, you may want to have a look at http://www.globaldialog.com/~jrice/diy/wavemaker.htm

It is NOT based on the usual 555 circuitry most wavemakers rely on. This design allows dead time between switching powerheads.

-=Bryan=-

[Reefmaster]

hey guys. the first thought i have is how well the glass, especially bigger tanks, will do with the differential expansion/contraction associated with heating or cooling with this sort of system. i wonder if 1. how efficient it would be, 2. if you could crack the glass with it.

as for controllers, i have been searching for people who know lots about data aquasition systems using a pc and interface. they are available out of the states, but very pricey. i read about a guy who wrote the code and used a 486 for the controller through rs232. i've looked at x10 but it seems a bit clunky to me. i'm more interested in rj45 through plc to completely automate the system, everything down to the r.o. coming on to fill the mixing bin, solenoids for dumping waste water and then pumping fresh mixed water into the system. that on top of lights, pumps, temp control including shutting off lamps in overheat, turning on fans, chiller, etc. anyone with this sort of idea in mind as well would kick ass. otherwise i'll keep up the search. shane

[DJ88]

Bryan,

Neat link.. I haven't drwan up the schematics yet. Still figuring it out as there are so many different parts/areas with the controller I am hoping to build.. Working on it tho..

Reefmaster,

I was wondering about that as well but was thinking that with a good heat sink compound and that the glass will be in contact with teh water on the other side the main worry of the glass cracking is during the initial turn on or heating. Once it is keepng the water temp set it should be fine. But that is what I have figured out. due to the fact that the glass is in immediate contact with the peltier device and the water it shouldn't affect eh efficiency too much.. and as it stands now I don't plan on using this on any large tanks. after all my tank is a 33. For larger uses a larger peltier device is needed.. Mod II.. [img]images/smiles/icon_wink.gif[/img]

[StirCrazy]

Darren, I have seen peltier's used directly in water (water coolers for computers) could the peltier maby be placed in the tank/sump as a heater replacement? This would elimanate the concerns of cracking the glass and also make it much more eficient as glass does have a small insalation value.

Steve

[titus]

Memorandum

10001-1 (Administrator)

9 Nov 01

Darren

<u>Aquarist Tank Controller</u>

1) Great idea! I'm especially keen on the peltier idea. However, I've never seen one that says it can be submerged (in saltwater) though.

2) If you can, let's route the PCB on the computer and send the design to a fab house. This way, you can pretty much mass produce it and the rest of us can solder on the components ourself.

3) If it is going to involve a PIC (like Victor suggested), or any kind of microcontroller, we can post the routines up here for people to modify/download/etc.

4) I have a friend who supplies robotic parts (ie BASIC stamp, LCDs, etc). Let me know once you finalized your parts/ideas.

T.T.H. Cheung
Administrator
Canreef Aquatics Ltd.

[canadawest]

I would be concerned with stray voltage or even electric shock when one puts metal plates with electricity flowing through them into salt water.

Don't think the fish would be too happy about the buzz either.

And how big would these peltier plate be? Even on a 33gal tank they would have to produce quite a bit of heat to dissapate throughout the entire tank. I suspect this project would be not applicable to my 100gal tank?

Otherwise I also am fond of the idea and would be interested in a finished product.

[DJ88]

Steve,

It won't be submerged. Part of the reason for chosing this is to use its capabilities with cooling as well as heating. Plus submering it would require some form of encapsulation to ensure no corrosion happens. I dont feel like getting this creative.

Just re-read your post.. I am assuming part of it was touching the water and part in the air right? Or else in a separate loop of water used for circulation.. Can you describe it more?? Curious now....

Shane,

With the device attached to the glass, the water on the other side of the glass will act as a massive heat sink. Ensuring that for the most part the heat energy is transferred through the glass. Some heating will happen but not to a sufficient degree to cause the glass to break. To ensure this doesn't happen as well, a proportional controller will be used to ensure that there isn't sudden treansferrance of heat in the plate touching the glass. To me the glass breaking isn't a problem unless the sump is run dry(which with baffles one side will be always full) or there are drastic changes made to the heating portion of the device.

Andrew,

The plate doesn't produce heat per say.. It moves heat in one direction or another. With current flowing in one direction it pulls heat from right to left(to give it a direction for you to visualize), reverse the current flow and the heat is moved from left to right.

This is another reason it won't be submerged. It won't have a differential in temperatures to move heat from one area to the other.

Titus n Victor,

I wont be getting much doen with it this weekend. Calculus n Physics midterms this week. Mind will be elsewhere..

I'll keep you posted tho..

[ 09 November 2001: Message edited by: DJ88 ]