Energy/power saving compressor application

[Apel]

Dear all, I am in rainy dark-searching energy saving option-for the existing system.

"aircooled condensers are used in this existing system."

We have total of 14 compressors in our 1st phase of the project.Two same kind of room are
cooling using these compressors.So one Room using 7 compressors.Out of 7, two are Danfoss
MT320-Hw4, 3 are MT160 and Another two are of MT 160-4VM type.Room size is 21Mx14M and
height 3M.The Lequid product is cooled down from 45 deg C to 10 Deg C.Every 24 hours 150 Ton
of this Lequid(Palm Oil Kernel) produce( means hot Product into the room and cold Out from
the room).But Present compressors are running by adjustable timers.Our concern is: How we
can save energy in this application?
adding few information.
1.Ambient Temperature Min 28-Max 34 deg C, Average 31 deg C.(Country-Malaysia).
2.Timer settings:40 minutes OFF and then 4 hours ON,approx. 20 Hours ON and 4 Hours OFF in
24 hours(a day) for all the compressors.But not all are starting /stopping at the same
time.There is a secuence.
3.I have measured Power the each compressorS taking are follwing:
compressor 1=21kw/440VAC/34A/50Hz
compressor 2=21kw/440VAC/34A/50Hz
compressor 3=27.6kw/440VAC/37A/50Hz
compressor 4=23.4kw/440VAC/23.4A/50Hz
compressor 5=37.7kw/440VAC/37A/50Hz
ABOVE EACH ONE(1-4) ARE USING 4 SAME SIZED(120W APROX)-CONDENSING FAN FOR CONDENSER.
compressor 6=18.5kw/440VAC/21A/50Hz
compressor 7=18.5kw/440VAC/21A/50Hz
ABOVE EACH ONE(6&7) ARE USING 3 SAME SIZED(120W APROX)-CONDENSING FAN FOR CONDENSER.ALL
CONDENSERS ARE OUTSIDE THE BUILDING.
fOR STARTING THESE ABOVE ALL compressorS AUTO-TRANSFORMERS ARE USED.
BLOWER-1(EVAPORATION) FOR compressor-1,2&3 FOR LINE-1 FOR THE SAME
ROOM=18.5kw/440VAC/21A/50Hz
BLOWER-2(EVAPORATION) FOR compressor-4&5 FOR LINE-2 FOR THE SAME ROOM=18.5kw/440VAC/21A/50Hz
and(440VAC 3 phase giving)V12=438VAc,V23=435,V31=432 aprox for all.
4.The room is well insulated but there is some workers(average 4 person always) working for
taking out the cold-freezed/solidified (oil became solid after cooling) from the room
through the gate.When they enter/exit the room some outside air obviouly enter the room.
5.PRESENT SYSTEM AIR-COOLED CONDENSER.SO I THINK IF WE CHANGE ALL THESE AIR COOLED SYSTEM TO
WATER COOLED CONDENSING SYSTEM THE COST WILL BE VERY HIGH.

[GXMPLX]

first let me say this is a very difficult question and though your information is good compared to others I'v read here is not nearly enough to pinpoint exactly what you need. So these are only general ideas.
What I would do is measure where and how energy is spent and then thry to work from there to see where you can save most.
The type of compressors you are using are not the most efficient for their application. I suppose you are unwilling to change them, like the condensers. But here you can at least save a 10% depending on operation.
So you are left with two (main) options one very good is use the heat for something useful. You cannot get too much heat at high temperatures but yes to warm water and only if you can use it to support or replace another device or you wan't be saving.
The problem is you need to know very well your operating conditions and how your condensers work not to jeopardize them.
Register operating variables like discharge temperatures because anything you install between the compressor and the condenser will afect it.
The second good option is to study (estimate) the load needed in the process and try to control your compressors on demand and not on time. This requires long data adquisition process and possibly more protection for the compressors.
Auto transformers are ok if you have a severe power limitation on compressor sturtup but if you can get rid of them during normal operation, you´ll be saving something.
You can get all sort of ideas to save power even magical additives, but if you don't first measure the operating contitions of your system (for long enough), you won't be in a position to evaluate if the change is worth the investment and you can even make things go much worse!

[Apel]

You can get all sort of ideas to save power even magical additives, but if you don't first measure the operating contitions of your system (for long enough), you won't be in a position to evaluate if the change is worth the investment and you can even make things go much worse.

Dear GXMPLX,

Can you suggest me what are the operating conditions you meant? are they power taking by compressors,Temperature of condenser coil in & out or Evaporator coil in/out..

I have measured condenser air temperature blowing by fan(after passing through coils) its around 50 Deg C.And what I saw in the cold room the temperature is different in the different corner of it.

[GXMPLX]

It depends on objective:

If you want to improve performance through control parameter modification then you should record suction pressure, discharge pressure, operation time of compressors and fans in relation to the load.

If you want to recover heat then you should closely monitor discharge pressure and temperature in relation to load.

If you want to save energy shuting off condenser fans then record discharge pressure and ambient temperature in relation to load.

If you don't know where to start then you shoud first record power consumption, though the compressors consume most of the power having data on consumption in relation to load can give you a better unserstanding on where you need to focus your efforts.

Sometimes big compressors do not run as much time as smaller ones or you can have equal size but one is running far more than another, this type of things you want to be looking for.