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Energy saving black boxes
Has anyone any experience of these so called energy saving modules fitted to compressor racks. Wired between the normal controllers and the contactors, they prevent the compressors from running when called for. From what I see they just interfere with the pressure control :confused:
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Re: Energy saving black boxes
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Re: Energy saving black boxes
Hi Rackman :)
The Energy managment systems were experimented with in a few supermarkets in the uk.
Some hold the compressors from starting,and float the suction pressure accordingly,Honeywell Elm call theres the supermizer interface this consists of filters and a bank of capacitors etc.If i recall it only came into effect once the compresssors second part winding for example came in,lowering the voltage and load. But this was quite often not the case,and was found to prematurely cause compressor failure.
The majority of pack controllers nowadays adopt methods of
energy saving by floating the suction when designated cases/coldrooms temperatures are satisfied ie when night blinds are down and thermal load is minimal.
Best regards.Mark :)
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Re: Energy saving black boxes
Thanks guys, these boxes are not VSD's or soft starters, they are manufautured by an Australian company Abbotly Technologies and sold in the US and Canada. They are also sold in Europe by the Energy Computer Company. They prevent compressors from running when the rack controllers call for them, this causes the back pressure control to go crazy.
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Re: Energy saving black boxes
Hi
The boxes work by either monitoring a target case or cases, or use a suction transducer, to monitor the packs load.
The information gathered is processed by a central unit and allows the target tempratures / pressures to rise or fall with the load.
the units work best with low temprature packs which have a fixed step controller (stongate step contoller).
If you only have one compressor or the compressors have variable capacitys (screws.) then the benifit of using sutch units is very limited
The boxes you have most likley are running on target cases as long as these cases are at temprature then the compressors will be off regardless of the suction pressure.
hope this helps.
Regards
Peter
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Hi Guys,
I have come accross a similar thing on norpe integral chillers.
The unit only has a small Danfoss compressor SC18 i think but it has this box wired in before the compressor electrics.
From memory :eek: the units are norplus 1.2m integs and the box is a Sava controlls SC4 unit.
Whats this all about then, i have seen them on Old and Newish units, some have them, some don't. is this some kind of energy saving thing that was tested but then given up on ?
Regards
Raymond
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I dont think the boxes you have Raymond are not the same as the boxes Rackman has Romond your boxes condition the voltage going directly to the compressor whilst the boxes Rackman has are inserted into the control circuits of the compressors
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Re: Energy saving black boxes
:) Hi all, its been a while.
Rackman, have come across these Abbotly things and argued with the owner of the company till I turned blue in the face.
They tried to get their gear installed in all new stores of one particular chain in oz. They do not belong in supermarkets, they may be fine when applied to a central a/c plant with old controls but with the control systems we see in supermarkets today these Abbotly crudbuckets don't even compare.
Basically it is its own little rack controller, with enough output modules to allow for each comp and unloader and a suction transducer is the only input into the rack control.
Its control algorithms are such that it assesses the suction pressure and the racks loading over a given time, from memory 15 minutes (its outputs are also voltage inputs - wired in series after real rack control output it can tell what comps and unloaders are being called for), it then proceeds to lock off compressors in a specific order according their run times and system's PREVIOUS 15 min interval.
It locks off comps until either its own time delay expires (max 12 mins) or until a high suction setpoint is reached, pre programmed by Mr Abbotly. It will then run normally for around 3 minutes (that is do nothing) and start it all again according to its gathered data.
I reckon I could do the same with a 4 channel timeclock and an LP pressure control!!! :D Except that would be better, it wouldn't rely on old data. These things do not tie in to any temp controls.
The company (Abbotly) mounted a discharge air sensor in the lowest SST cases on each rack and a "product simulator"(probe in a canister against back wall of case!) to monitor temps while they "fine tuned" the settings.
Fortunately it has a bypass feature, our service mechs usually bypass it whenever on site as it causes too many service calls, glass doors rated at -30'C SST running at -20'C SST struggling to pull down off defrosts, etc.Not to mention the floodback (as Marc says). But Mr. Abbotly keeps dialling in and turning it back on (they installed a GSM modem - should unplug it! :eek: )
If in doubt, rip it out. There's better ways to save energy without comprimising product temps... proper system design, a willingness to spend a little to save and proper system commissioning. If these things were THAT GOOD then they'd stand alone as a rack controller themselves. But they don't, they can't cut it with the real controls on the market, they don't even control discharge pressure... :confused:
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Re: Energy saving black boxes
Hi 750 valve :)
Good to see you online again,what you been up to????things busy your end ?
Mark :)
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Re: Energy saving black boxes
The only black boxes, that I have seen are the ones that condition voltage. Many of the companies have claims that they will condition the power going to the compressor, and save you energy. They also claim the benefit of soft starting the systems. The sales pitch is the demo the do with a standard electric motor. They plug it in to an outlet and run the motor, clamp on an amp meter, and you see the voltage that motor is using. Then they plug in the motor to the box, and re-clamp the amp meter to show you the new voltage being used. But in reality, you will probably never see those savings in the overall picture.
I personally am not in favor of using the black box.... If it was like the black box on a jet, and told you why your compressor crashed, then I would probably be more interested.
Just my two cents.
Tight lines!
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Re: Energy saving black boxes
Dropping the head pressure is the preferred energy saving method nowadays......
Especially in the uk :D
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It always has been one of the best and the easiest ways to achieve big savings.
I used to have the bad habit in the past to set my HP settings on condenser fans always on a fix of 15 bar or 220 psi.
We will bury next week or the week after a copper ground heat exchanger (3 x 100 ft 3/4 copper) to increase efficiency on a pack.
We have installed a pack last summer which runs now (already some months) on a HP of 125 psi (8 bar) and a LP of 70 psi (or 4,8 bar) This gives us a very high COP.
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Re: Energy saving black boxes
It’s far more efficient to allow head pressure to
“float” with ambient wet-bulb temperature, down to
a minimum safe level for a given system. With floating
head pressure, the system works only as hard as
it needs to under all weather conditions, yet safety
and reliability are maintained. :D
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hey there ,can somebody tell me what is the price of the unit from Abbolty technologies and does anyone have manuals on how to install it ???? :P
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Shogun,
Can you clarify this more specific please? It's also the technique Danfoss uses.
I know it's sometimes not worth letting run all the power consuming condenser fans because this energy could cost more than the savings.
Purely seen on COP, the lower the HP the better. What have I missed?
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Quote:
Originally Posted by Marc O'Brien
Shogun is being very vague in his assumed definition of "floating head".
Also, the extra running, water and water treatment costs in acheiving the "wet bulb" shogun speaks of most often excludes it as an option.
Shogun doesn't talk from experience is my guess.
Yes I do I have owned a magnetic head floating on a layer of air away from the recording surface for a long time now :D :D :D Thanks Marc for keeping me true and straight, your the greatest Boy, it's so comforting to know WE have you to straighten us out when we are so ... er incomplete?:D
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Re: Energy saving black boxes
Quote:
Originally Posted by Peter_1
Shogun,
Can you clarify this more specific please? It's also the technique Danfoss uses.
I know it's sometimes not worth letting run all the power consuming condenser fans because this energy could cost more than the savings.
Purely seen on COP, the lower the HP the better. What have I missed?
Peter, By floating head, I mean letting the head pressure float
down but still maintain a minimum pressure setting which is determined by the expansion device, because it will require a certain pressure to be available for it to deliver sufficient refrigerant. Thermostatic expansion valves are the most sensitive component in most systems, as they generally require significantly more pressure to operate efficiently than other types. However they will still operate satisfactorily over a range of lower pressures. With regards to the wet bulb issue, I was referring to when you are useing an evaporative condenser :D
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Re: Energy saving black boxes
OK, then I 'm following you now Shogun. With air cooled condensers, we always maintain now a minimum HP to overcome the spring force in the TXV.
But in the past, we always setted this value - like most still do - we could expect in summer conditions (240 psi or 15 bar or +/- 35°C with R404a) So this was too high for winter conditions where it's possible to lower the HP to a certain level with big savings on compressor side.
We also select now TXV's with a DP of 6 bar instead of the 10 DP we used in the past.
Like said before, teh pack we installed last summer in a meat cutting factory runs now on +/- 70 psi LP / 120psi HP. This gives COP's of more than 6 !!!
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Re: Energy saving black boxes
Hi Mark, yeah been pretty busy. Enjoying a well earned break right now :cool:
Boutrous, it pains me to tell you this as I really dislike these things :mad: , but visit www.abbotly.com.au they have offices elsewhere in the world.
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Well 750 , i visited that site but no prices figures there , so if you know approximative prices i'll be glad if you post it .
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Nah sorry, no real idea of price. The installation I was involved with had 2 x 4 comp rack and 1 x 3 comp rack, on each rack was installed one controller with the only amount of output blocks req'd, different for each rack (unloaders on two racks) and also on each rack one temp monitor for one case temperature. Cost was around $8000 Australian from memory (give or take $1000) including wiring and commissioning.
Honestly they're NOT worth it, you're better off with a timeclock to lockout (save $) and a pressure or temperature control to override (get COLD again), or even better, spend the time commissioning the site for all conditions.
What's the project that requires these controls?
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Thanx 750 ,
It's a supermarket project that we are designing and that if we take the job we will excecute the job on field in April i think.
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Re: Energy saving black boxes
Hi botrous :) welcome to RE
Many pack controllers adopt energy saving methods in different ways, me personally would rather see a close control method of compressor staging,to coincide with constant case temperature monitoring from the front end.
Prefered modern methods are floating the head pressure,and when case temperatures permit to float the suction.Floating the head pressure is advised in both LT/HT application,however floating LT suction is not advised :)
Many energy saving modules ive seen through the years are totally bypassed and are to blame for a few premature compressor failures.
The choice is yours.
Best regards Mark
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Thanks for the information Mark , i'll have a look to the links ..
And thanks for welcoming me , i'm really enjoying this forum , it's professional and friendly
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Botrous, throw the Abbotly idea in the bin, spend the time commissioning the site for all conditions, this will save you the $$$ the customers after and also time wasted... PS really pissed, this is hard. Might give up as Im pressing backspace more than any other key. PS Abbitly sux bigtime. If your really Hellbent on using them, I'll give you a quote to do the same thing for about 1/4 price!!!!
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750,how do you commission a site for all conditions.
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How would one, control variables other than certainties.
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750 thanks for your advise , but considering the Abolti systems isn't a "SIN" no ????
We all consider the job and try to do our work the most effective way for us and for the customers , anyway i'll be glad if you show me the way for the 1/4 price
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Re: Energy saving black boxes
Botrous its just a timeclock that overrides on pressure, you can do the same thing with mechanical controls for cheaper and possibly more reliable.
Mark, obviously its gonna be a compromise, but rather than say set up a system for floating heads and not spending the time to see the effects on system under summer, winter, part load, full load, case superheats, find best compressor staging and delay timers, etc. Not just set it up as you did the last site. In this case, push the suction pressure control as high as possible giving the black box no chance to save $.
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thanks 750 for the advise , you are saying that using electromechanical devices is more reliable and sure you are right . . . but can you do me a favor ?
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Re: Energy saving black boxes
Quote:
Originally Posted by Marc O'Brien
Fuzzy Logic.
Reading this post I noticed that no you one gives a sh## about what you have to say :cool: Sorry I've been busy with my family at my other home on the Colorado River(Poco Casa Del Rio) playing with all our toys. Gee for as dumb as you say I am, I sure am able to live the good life. Coming from parents of Mill Workers and working my way through college,becoming the Craft Head for Steamfitting & Refrigeration with over 120 craft workers just in my section,becoming a professor at a community college, being selected to two Honerarysin college, becomeing a Certified Energy Manager with the Association of Energy Engineers, being a Local 250 "Certified Pipe Fitter" and a Certified Member of RSES and an ASHRAE member etc. I haven't done too bad, maybe you too can be as great as I am and have as much respect from your peers ;) but don't hold your breath :p
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HI shogun ,
appreciate you career achievement.
Would you pls tell sth about energy saving control?
Our chillers is still on-off control. How to take on the energy saving control for the specific use?
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Quote:
Originally Posted by lc_shi
HI shogun ,
appreciate you career achievement.
Would you pls tell sth about energy saving control?
Our chillers is still on-off control. How to take on the energy saving control for the specific use?
Ic_shi, Do you have a building automated system, with open protocal / Are the chillers for Air Conditioning? Are they now on time clocks? Give me some background info on what you are working with and I will try to guide you to the best source for infomation :)
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Re: Energy saving black boxes
Quote:
Originally Posted by Marc O'Brien
You're too f u c k i n g stupid to see the humour. I wouldn't be suprised if that was a family trait either.
Get ahold of yourself "sh33 for brains" your loosing it! :rolleyes:
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shogun,
i'm providing chillers not take on the whole system. My chiller is only on-off control by return water temp. i don't know the system compay how to incporporate the chiller to the building aumated system. could you give me some introduction or useful links? thx.
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Re: Energy saving black boxes
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Re: Energy saving black boxes
Quote:
Originally Posted by lc_shi
shogun,
i'm providing chillers not take on the whole system. My chiller is only on-off control by return water temp. i don't know the system compay how to incporporate the chiller to the building aumated system. could you give me some introduction or useful links? thx.
Ic_shi, Please read this and see if you need more I have a lot of sites you can learn more . Do you have an understanding of Direct Digital Controls ...If not then you should start by going here: http://www.ddc-online.org/
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