Help with new electronic refrigerator controller !

[EngiGal]

Hi everyone :p ,

I am a student currently doing my engineering studies and I am new to this forum. I hope you guys can help me with my project.

I know that programmable controller is sometimes hard to understand. As part of my project, I am currently researching on a new simple (no programming involved at all!) to use electronic commercial refrigeration controller for beverage coolers/refrigerated showcase.

These are some of the features I have thought to be useful:
· Automatic defrost
· Overheating condenser alarm
· Protection against irregular mains power (browns out)
· Tamper free temperature setting

Since you guys are expert in refrigeration and I have no experience at all in this area :confused: , I would like to know about your thoughts, opinions or suggestions on what features would you like to have in a controller.

Oh, one more question do you think it is important to have the controller splash proof and waterproof?

Thanks !! :)

[Peter_1]

Hi EngiGal,

If you will later search for a job and make such a polite introduction, you will be hired :cool:

Have once a look at http://www.invensyscontrolseurope.com/InvensysControlsEurope/en/ProductsServices/Eliwell

http://www.dixell.com/page.php?sid=b1c89d4cbd9105bddba317ca70b30e21&pageid=PHOME001&m58LangNew=ENG

and the one with the largest product scale and posess now +/- 80% of the OEM market

Smart defrost in the controllers is standard

http://www.carel.com/carelcom/web/eng/mercati/refrigerazione.jsp

Smart defrost in the controllers is standard.
Overpressure of a condensor is much more important then overtemperature. Some controllers have a digital input for this overpressure.
Irregular power? What do you mean with this? If there 's an overvoltage, then not only your controller will be blown away.
Tamperfree temperature setting is available, eventually password protected.
Splash proof is standard with most controllers.

So the product excists already since very long time.

[Tycho]

http://www.ra.danfoss.com/ra/Products/ProductCatalogue.asp?BA=&Division=RC&HL=4&HLID=648&AppID={c2a95dac-5e01-47df-92cd-5972d837cf1a}&selectedTab=LI# PDF file with information on the Danfoss AKC 72A



Tamperfree temperature setting is available, eventually password protected.

Sometimes it's best to leave it open for the customer to tamper with :D he will only do it once tho :)

[liverpool Eng]

Smart defrost in the controllers is standard.
Kuba Defrost on demand is the only one i have seen that donot run on a time factor.


Overpressure of a condensor is much more important then overtemperature.
This is so closely linked that it amounts to the same thing.


Irregular power?
A brown out is a voltage drop that will make your equip go overcurrent and blow fuses or trips.

[Andy]

Hi EngiGal
All the controller mentioned can have the "set temperature" limits from been set too high or too low (max and min set).

We fit a phase fail relay to all our control panels, this senses phase failure, under voltage and reverse rotation, a delay timer is set to delay the main control circuit on after a power fail, basically stops the compressor cycling in and out on low voltage ect.

Kind Regards. Andy.

[Peter_1]

Kuba Defrost on demand is the only one i have seen that donot run on a time factor.
This is so closely linked that it amounts to the same thing.
A brown out is a voltage drop that will make your equip go overcurrent and blow fuses or trips.

Ever scrolled through the parameters of an Eliwell or a Dixell? There is a smart defrost.
And better defrost once more with a defrost end temperature then run on a 'smart system' where the evaporator blocks.

I think you're speaking of a Kubatron. They're very expensive and by the time you have saved this money with the savings they predict only with the defrosts...?

Why are so many AC units and scroll compressors equiped with a discharge temperature sensor?
Discharge temperature has little to see with condensing pressure. Subcooling and superheat makes that you can't solve this with a temperature sensor.

[EngiGal]

Thank you so much for all of your replies and suggested websites. I’ll have a look through them later today.

I agree with most of you that features like smart defrost and over temperature alarm is not new features in refrigeration controller.

I got a question in regards to Andy’s reply. Is it correct that the phase fail relay stops the compressor and other major parts of refrigeration when it senses a drop in voltage? And when the voltage returns to normal, after a time delay it will then turn the compressor on again? If I was to include this feature in the controller, do you still need to the phase fail relay?

However, I was wondering about what features that can be added to the controller that will solve most refrigeration problems. What other diagnostics would be best? Would it be best then to have an over pressure alarm ??

[Andy]

I got a question in regards to Andy’s reply. Is it correct that the phase fail relay stops the compressor and other major parts of refrigeration when it senses a drop in voltage? And when the voltage returns to normal, after a time delay it will then turn the compressor on again? If I was to include this feature in the controller, do you still need to the phase fail relay?

However, I was wondering about what features that can be added to the controller that will solve most refrigeration problems. What other diagnostics would be best? Would it be best then to have an over pressure alarm ??

Better keep the phase fail seperate on 3 phase systems as I don't like the idea of putting 415 volt on the back of a small controller:(
Single phase fail and under-voltage on the controller would be good:)
Also superheat alarm or a counter that counts the number of system L.P faults. Loss of refrigerant alarm such as this would be a major energy saver;)

Kind Regards. Andy:)

[EngiGal]

Thanks everyone for your opinions and advices...I now have a better understanding of what features a fridge controller should have...I really appreciate everyone's quick reply !!

[NoNickName]

Carel is rubbish, though the market leader.
Dixell is the way to go.

[Renato RR]

Why Dixell?

Renato

[NoNickName]

Try it or read their manuals and then you will discover yourself.

[Andy T]

Liquid line over temperature alarm.Good for Condencer blocked with dust or fan failure.

[Peter_1]

Carel is rubbish, though the market leader.
Dixell is the way to go.

Why Dixell, all those thermostats are +/- copy's of each other (Dixell/Eliwell)
As far as I remember, Eliwell was sold to the Invenys group and the founders of Eliwell started all over again with Dixell.

There are only a few components inside these thermostats, a small microprocessor, a transformer and some relays. That's all. There can't go seriously wrong with it, with any brand.

Used almost all the brands, we installed one of the first Dixell XJ500 in Belgium and it was a complete nightmare. You could see that the engineers of Dixell hadn't listen to the techs in the field.
That time, Eliwell was much better

Have now two XWEB 3000 running and the software of Carel is much better.
Especially the user friendly interface of Carel is better to understand by a not-computer minded user.

You can feel that Carel is much more listening to the needs of the market. They're making a product that suits most of the needs. Like their PCO² gamma.

What's wrong with Carel? The programming abilities are much larger then any brand.
Why do the possess +/- 80% of the OEM market? They don't have the cheapest product.

What's a little disappointing is the technical documentation they provide.


Eliwell

[NoNickName]

Peter, you can't be serious. Carel is rubbish on the side of software. Hardware is ok, but software sucks.
Dixell IC line of microprocessor regulators (I'm not interested in thermostats) is skies above Carel.
We are phasing out Carel for poor support, insufficient documentation, and lack of I/O channels.
Carel is being abandoned also by major producers.
And they are also the cheapest on the market.
Their programming skills are below the average.

[Andy]

Peter, you can't be serious. Carel is rubbish on the side of software. Hardware is ok, but software sucks.
Dixell IC line of microprocessor regulators (I'm not interested in thermostats) is skies above Carel.
We are phasing out Carel for poor support, insufficient documentation, and lack of I/O channels.
Carel is being abandoned also by major producers.
And they are also the cheapest on the market.
Their programming skills are below the average.

Carel have been taken over or some such likes

They still have a pretty impressive product range.

Kind Regards. Andy:)

[Peter_1]

...Dixell IC line of microprocessor regulators (I'm not interested in thermostats) is skies above Carel...

Is this the range of the common electronic thermostats?

The rest of your post, I see it as your personal view, I heard other stories and I also have my personal experience.

[NoNickName]

Is this the range of the common electronic thermostats?


No, I'm talking about the parametric controllers range, series IC100 and IC200, specifically the IC261L and 281L