Electronic Controls

[Bones]

Hey guys, not sure if this is the right place to post this, but figured you guys would be the ones using digital/programmable controls the most...

my situation:
my boss is building a small coolroom for his up and coming fishing trip to the red centre... (Northern Territory, Australia). and he not being into computers, or anything to do with new technology advances within the last 10 years lol asked me if it was possible to get an electronic controller for his coolroom which would cycle the room when it got down to say -20 and come back on at say 5-10'c to conserve power through there generators/inverters etc to allow them to run other things for longer periods.

Being programmable, i would imagaine that all i would have to do would be set the paramaters anyway - as i have not been able to find out any specific operating ranges for the controls available here (Dixel) other then med/low temp... which makes me think you cannot insert your own differentials... and not playing around with them day to day thought i would ask the knowlege base here

[Mark]

Hi Bones

Have you thought of coldroom temperature pulldown times?.It may be a better to cycle c/u and fans when box temperature satisfied within a smaller differential ,as the pulldown times may be longer if the box temperature has risen to the set points you explain.
In other words the run time would be proportional to the associated box/product temperature.
There are a number of options regarding electronic temperature control my first question would be how much you want to spend?.

Kind regards mark

[Bones]

the box will have no fans, it is going to be fully constructed out of 100mm pannel... and he is going to use pate evaporators around all the internal walls and roof to i think.

because it will be loaded with ice fish etc... his idea is to run it down low, and if they want to move camps etc the room will be extra cool, as well as have long off periods once temp is acheived, with the nice insulation and the product being so cold...

i'm not sure exactly how much he wants to spend... he seemed interested at the prices of the dixell controlers.

after working on ice boxes with a similar setup... pull down time should be around 15 minutes to go from 35'c to 0'c and and about the same to get to his -20'c setpoint.

I'll have to take some photos of the finnished product, only being build out of scrap for the trip... if he gets motivated enough to finnish it off to meet the deadline of actually going lol... but you get that.

[chemi-cool]

hi bones,

what you need is plates like they use in icecream trucks.

you refrigerate down to -35 and the cold liquid in the plates, preserve the temp for as long as one day.
Eutectic plates is the name, you can install as many as you like.

check it out.

chemi

[Mark]

yes chemi eutectic plates could be used,however would the high price of eutectic plates not put him off.

[chemi-cool]

hi mark,

I am not dealing with bones`s boss finencial situation but trying to halp the young man

If not , bones will be happier to seat in the pub instead of making a fish box for his boss.

I am sure he is not getting any extra for doing it.

chemi

[Mark]

my boss is building a small coolroom

I thought bones was asking about the control side

[chemi-cool]

in that case, Dixell RX 20 will do, just sut the diferential for maximum and there you go

chemi

[Peter_1]

in that case, Dixell RX 20 will do, just sut the diferential for maximum and there you go

chemi

Eutetic plates I heard??? Remember the pictures I posted some time ago how we did it in the past?
We're making them ourself +/- 30/year.
Eutectical solution should be chosed according to the temperature you want in the room.
Temperature is afterwards not adjustable anymore (in the most common setup). Or you need a double insulated wall and a fan..

If you need info, give me a call.

Regards
Peter

[frank]

How can you have a coolbox going down to -20 and then back up to 5-10 deg? What about the product freezing, thawing, freezing etc. - don't think I would want to eat that stuff!!

[chemi-cool]

thats why you dont go fishing in the Northern Territory, Australia!

chemi

[iceman007]

The thing is with eutectic plates that they are slower to respond to temperature increases than other methods (ie. forced air), but can work quite well. It's important to choose the correct ones for the temperature aplplication, which Peter has already mentioned, because the eutectic solution depends on the application.
How are you going to re freeze the solution Bones ? I've heard of some places having two lots of plates with one being refrozen with the other set in the box, which seems a bit of a pain. Are you going to use a compressor to refreeze the solution overnight? We did one ages ago for a client at a firm I worked for and used a sanyo air con compressor with a water cooled heat exchanger, but it's been that long ago I can't remember model numbers or anything.

Reagards
James

[Bones]

How can you have a coolbox going down to -20 and then back up to 5-10 deg? What about the product freezing, thawing, freezing etc. - don't think I would want to eat that stuff!!

hehe.. frank how true, it is his decision after all I will not going on the pilgramidge so i dont really care about the quality of his food lol. he will be eating more 45'c red dirt then anything, i did talk to him about it but he didnt seem that worried.

the hole room is the right size to fit on to a box trailer, height is around 1m rectangular shape with two swing type opening doors above that height (total hight to peek 1.6m give or take), so it looks like a regtangular square with a rectangular pyramid sitting on top if that makes sense with a swinging door each side.

we will be lining the inside walls of the rectangular box with plate evaporators we have scored from decomissioned portable fridges here (we have enough to do the job, and they are all the same). they will be lined off the walls 5mm to allow air fall even if the box is packed to the brink

the bottom of the box will be filled with there ice, beer, there catch and any hitch hikers they kill along the way i guess lol

becuase the fish and food etc will be in the ice all he would like to do is run the fridge unil it hits -20 and be off until it reaches 5-10'c (i think he would be better off setting it to cylce off at -10 and back on at 0, so his ice wont melt).

in that case, Dixell RX 20 will do, just set the diferential for maximum and there you go

thanks chemi, i will check it out i'm only worried he will try and change his settings once he is way way outback because he has set it to pull down too cold and ring me to tell him how to change it... if he does maybe i'll charge him for a service call lol

where can i get some information about these "Eutectic" plates? are they ***** filled or just refrigerate a brine solution which is pumped through like a water chiller setup?

Thanks all, for your help so far much appreciated

[Peter_1]

where can i get some information about these "Eutectic" plates? are they ***** filled or just refrigerate a brine solution which is pumped through like a water chiller setup?

Thanks all, for your help so far much appreciated

Haven't read my previous post Bones? Well, well, well....!

We make them ourself, in fact, we let thme make now according to our specs, now already for more then 10 years, +/- 30 plates/year, always for mobile vending trucks applications.

I will make some pictures of it the nex time.

Peter

[chemi-cool]

hi bones,

attached is a pdf with the RX20 instructions.

see how to lock the settings.

chemi

p.s. file is too big, send me your email and I will send it.

chemi

[Peter_1]

With almost all Dixells (not mentioned in the technical leaflets, at least those we have here in Belgium), if you push the up and down button simultaneously 5 seconds (both are located on the upper button left and right) then you lock the display PoF en Pon

[Bones]

sorry peter... just all this information reading everyones posts Some pictures next time you are building would be great! as i have never worked on any yet... and you can never know too much information

I will PM you my email address now chemi, cheers mate