Calling All Sparky's (electrics) Need Help With Simple Schematics

[funkyyyy]

Okay heY everyone, I am in desperation for confirmation that these schematics will work. This seemed like the most suitable forum section to post this, apologies if it is not.

I am in year 12 doing my HSC, and for DT I have decided to construct a guitar cabinet in which ambient temperature can be controlled and monitored (preserves guitar in extremes of weather).

I have come up with my system, and will do my best to explain it to you below. Could you please tell me if it would work?

Okay as you can see I am running power from the wall, into the thermostat, and the thermostat is distributing power according to what temperature I set it at. I am using the ATX power supply as an "inverter" so I can cool the case with the 120mm fans which run on 12V instead of 220V. What do you guys think? Here is an image of the thermostat's inputs and outputs:

CHEERS

 

[crozdog]

concept seems fine. AFAIK, the stc1000 will do just what you want.

Checkout this site for info on wiring it up. http://homebrewrecipes.kirschbaum.co.nz/di...-to-wire-it-up/

Be aware that the unit isn't "distributing power" it simply switches on the appropriate output which you have wired power to.

A couple of thoughts:
1. Instead of adding an ATX PSU for 12v to drive your fan, get either a 12v plugpack OR a 240v fan.
2. Mount 2 GPO's on the case & wire the outputs to them label 1 "heat" & the other "cool". it will be a much neater self contained unit & allow you to simply plug in the heater & plugpack/fan. Note you can't use a a double gpo as the outlets share the same wiring.

 

[funkyyyy]

You're a lifesaver mate, the jiffybox and GPO's is such a good idea, I will use a 12v plugpack. So to connect that to the fans (4 Pin molex (+ / - & Ground x 2) I use cut the end of the plug pack and use a wire joiner to connect the wires from the fans to the plug pack? I'm using two fans, how would I go about running two off of the 1 plug pack. Cheers

 

[adniels3n]

If the mA rating of the plug pack is more than the 2 fans combined, it'll be ok. Should be written on them.
You understand that the heating /cooling outputs are the active wire only? ie. 240VAC active is joined from 1 onto 5 & 7, waiting to turn on & supply power out of 6 & 8.
The Heating/Cooling circuits Neutral returns back to 2.

 

[funkyyyy]

Thanks, I'll look into that. And yeah It makes sense to me now, I originally mis-understood the temp controller but now I will use this wiring diagram:

 

[DJR]

Fans don't really cool at all, they will just equalize the inside to whatever the ambient temperature is.

I'd look at a peltier element which has a "cold" and "hot" side - a kind of solid state fridge. Put a heatsink on the "hot" side and blow your fans into that, the peltier will pull heat energy out of the cabinet and discharge it on the other side with the heat sink and fans.

Lots of small wine coolers use peltiers as they are cheap, but not as efficient as a compressor.

Edit: Fans will cool if you evaporate water as well, the evaporation of water will remove heat, look up evaporative coolers and you might be able to do that too.

 

[Malted]

Watch out that you don't get this situation: cold = condensation = wet guitar = dead guitar

 

[crozdog]

Fans don't really cool at all, they will just equalize the inside to whatever the ambient temperature is.

I'd look at a peltier element which has a "cold" and "hot" side - a kind of solid state fridge. Put a heatsink on the "hot" side and blow your fans into that, the peltier will pull heat energy out of the cabinet and discharge it on the other side with the heat sink and fans.

Lots of small wine coolers use peltiers as they are cheap, but not as efficient as a compressor.

Edit: Fans will cool if you evaporate water as well, the evaporation of water will remove heat, look up evaporative coolers and you might be able to do that too.

Peltiers are a great idea but they will draw more current than a plug pack will supply - a modified ATX PSU would handle the current easily. As DJR says they are cheap - look on ebay for "Thermoelectric Cooler"!

I'd put a fan on the cold side too to distribute the "cold" through the cabinet.

Re running 2 fans off the 1 supply - like mudzzy says, as long as the total current draw of the 2 fans is less than your supply can handle, simply connect (join) the 2 fans to the 1 supply.

 

[funkyyyy]

Would this do the trick?

http://www.ebay.com.au/itm/THERMOELECTRIC-...=item2c5db435c9


So attaching a heat-sink on the "Hot" side and a fan on the "Cold" side to push the cold air back into the cabinet? How efficient would one of these be to cool a cabinet that is 1365x555x150mm? And you think running these off of the power supply would work better? My ATX power supply plugged into the female plug of the cooling on the jiffy box will switch on automatically (providing the green and a black earth wire are joined together - switching the PSU on permanently) to power the Peltier and Fans, Running off of the 12V wires on the Power supply? Sorry if that sounds confusing lol.

Thanks

 

[Doogiechap]

Hi Funkyyyyy,
Good on you for getting in to this a bit more deeply
Peltier wise I can't comment formally on it capacity or ability to cool that capacity (thermodynamics is too tough for my head) but I don't think it would make a huge impact but certainly better than nothing at all. I guess you might be able to buy a heatsink with enough area to fit two peltiers and then grab another if you are unhappy with the performance. Your ATX may be unhappy starting up under load and if that is the case then you can ditch the GPO for the cooling side and just run the +ve 12V wire of your ATX PSU via pins 7&8 of your controller and leave it running the whole time. Have a sniff around google and you might find it an advantage in providing some loading on the other rails (outputs) of the ATX. This will help it to run with more stability and possibly give a better output particularly if you do end up running two peltiers with a capacity to draw 6 amps each.
Good luck and keep us posted on how you go !
Cheers
Doug

 

[funkyyyy]

Ah yes I thought of that initially however this PSU must start up under peak load from at least 90VAC however if it doesn't like it I will just run it directly out of the thermostat itself although I don't think that it will be an issue. As for running the Power supply under load to get better stability, I will be running at least one peltier, 3 fans and some lighting off of different rails. I'm not sure if this current draw will be enough to maintain stability but I am quietly confident it will be

 

[mgill]

A couple of quick notes when using peltiers. Peltiers are a heat pump, i.e. they will transfer the heat from one side of the plate to the other. So essentially you can have the peltier heat or cool depending on what polarity the voltage is plate 1 will get hot and plate 2 will get cold, swap the polarity and plate 1 will cool while plate 2 gets hot. I am not sure about the controller you have but a lot of controllers will allow you to have two set points (one for heating and one for cooling) or an adjustable timeout to switch between heating and cooling. If this is the case with this controller you could set it up to switch between heating and cooling by adding 2 240V DPDT relays (if you do it in parallel with the GPO's you are wiring in you could have a 12V and a 240V output option. The peltiers are very sensitive to swapping between heating and cooling and the two plates need to be around the same temperature when you do so, so if you plan on doing something along these lines make sure that you can have a delay or two different temperature set points. The other thing to note is although computer power supplies have a high wattage rating, this is a total wattage divided into the other rails as well (15V -15V 12V 5V etc). So you may want to look at a lower wattage peltier (you can get 40W modules from jaycar for about $15).

 

[funkyyyy]

I just finished wiring up the STC-1000 inside of the box and I must say it has worked out brilliantly. Now just need to wire my heating / cooling devices to the male socket and mount it in the cabinet and I'm done. Here's a pic of my progress so far:

Thank you SO much for all your help guys, I appreciate it!

 

[crozdog]

I just finished wiring up the STC-1000 inside of the box and I must say it has worked out brilliantly. Now just need to wire my heating / cooling devices to the male socket and mount it in the cabinet and I'm done. Here's a pic of my progress so far:


Thank you SO much for all your help guys, I appreciate it!

Keep the progress pics coming. good work.

don't forget to document it ;-)

 

[funkyyyy]

Thanks mate, yeah definatley, this will thicken up my folio

I have a quick question on peltiers. I just ordered a 40x40mm one off of ebay from a guy in WA.. here are the specs:

"Operates from 0~15.2V DC and 0~6A
Operates Temperature: -30 to 70C
Max power consumption: 60 Watts"

So I'm assuming that you put a heat-sink on the hot side and a fan pushing the cold air out from the cold side? I'm just going to wire this up to the ATX power supply and use it as an inverter seeing as it's readily available =)

 

[crozdog]

Thanks mate, yeah definatley, this will thicken up my folio

I have a quick question on peltiers. I just ordered a 40x40mm one off of ebay from a guy in WA.. here are the specs:

"Operates from 0~15.2V DC and 0~6A
Operates Temperature: -30 to 70C
Max power consumption: 60 Watts"

So I'm assuming that you put a heat-sink on the hot side and a fan pushing the cold air out from the cold side? I'm just going to wire this up to the ATX power supply and use it as an inverter seeing as it's readily available =)

I personally haven't made anything with peltiers but believe that you will need a fan on the hot side to help remove the heat. This link has some info you might find useful http://labjack.com/blog/end-table-drink-cooler

 

[funkyyyy]

Thermostat unit all wired up and completed, ready for heating & cooling devices to be assembled (waiting on peltiers lol). Here are some pics Just a quick question though - I'm using a 150w ceramic lamp that fits in a socket (like a normal light bulb socket) and it has two contacts for wiring which are not labelled. How do I wire this up to the 240? Just two live wires in a circuit to and from the outlet? Or do I need a neutral and live wire.. thanks

 

[mgill]

definately put a fan on the hot side, and if you want to protect the peltier from possible damage you would be best to wire a thermostat onto the positive wire to stop power going to it if it gets above a specific temperature (in this case it says maximum operating temperature 70 degrees) http://www.jaycar.com.au/productView.asp?I...mp;form=KEYWORD. Simply cut the red wire to the peltier and stick this device in between. then mount the device to the "hot" heatsink. It may be $5, but it is good insurance against killing the peltier and the pain of waiting for a new one to arrive.

Another important thing to note is insulation. You will increase the effieciency dramatically if you make sure you have good insulation between the "hot" heat sink and the "cold" heat sink, so i would make sure you get some polystyrene foam and sandwich in between the gap of the two heat sinks (an air gap is a very poor insulator and as such the two heat sinks will try and equalise the temperature between them.

I am in the middle of a building a PC based temperature controller with built in alcohol sensor for my homebrew system which I am utilising the peltiers for... so i have done a fair bit of research on them.

More than willing to help out if you have any issues, its good to see your enthusiasm.

 

[funkyyyy]

Great idea mate, I'll go pick one up tomorrow. I'm a really big noob with peltiers, basically I ordered two (specs listed above). I am going to mount an AMD heatsink/fan with some arctic silver 5 (thermal compound) inbetween the hot side and the heat sink. To move the cold air coming from the other side, I thought of getting some sort of tubing lined with aluminum foil or something, with a fan at the end sucking the cold air out into the cabinet. I noticed you were mentioning "cold" side heatsink, am I supposed to mount a heatsink on both sides of the peltier?

Thanks

 

[kelbygreen]

ok I have to be honest I havnt read threw this entire thread. But on peltiers you have to get the volage right (well with CPU's as I researched) as not enough watts and it wont work properly and to much watts and it can freeze the cpu. But with my cpu phenom II they over clocked to 6.3ghz using dry ice so I guess cooling isnt the issue where old amd cpu wouldnt take - temps to well. for your case I got no real insite but seems like people in here have some idea