Is BIG really good??

[Tanggy]

Hi all. Just got my 5ft up and running. Have heard so many people saying that you need to get the biggest chiller you can afford to chill a tank and to save electricity. It sort of became a myth to me. I had my doubts but what they say sounded logical. A big chiller can cool faster and runs shorter and inturn cost less electricity. Where as a smaller chiller take longer to cool and waste electricity.

I took it at face value until recently when I needed a chiller for a bigger tank did I did some calculation. They are as follow.

Size: Comsumption

1.25 HP chiller : 1100watt .

0.5HP Chiller : 440watt

So lets say a 0.5 chiller runs for 12hrs a day ths total comsumption:

440x12=5280watt = 5.28Kwh

If 1.25 HP runs for 6hrs (From what I observed longer.)

1100x6=6600watt = 6.6Kwh

From the results you can see that the 1.25HP consume more power.

Inorder for a 1.25 HP chiller to save money, the chiller needs to run for less than 1/3 the time of what a 0.5 HP will run to cool the tank.

For my personal experience, I am running a 0.5HP for my 5ft. I got it to test this theory. As I am using 2x250watt MH with 2x36watt antinic, I didnt see the need of a 1.25HP chiller. The 0.5 is rated for up to 1000ltrs. Mine is like 180+ gallons minus after minus the rocks and sand (which is approx 750ltrs).

Not unless I plan to use like 3x400watt MH than I would have gone for the 1HP (not 1.25). Want to put my theory to test and found that my chiller runs an est 10hrs a day to keep the temp between 26-27deg. In order for a 1.25 to give me savings, it cannot run for more than 4hrs which I think is highly unlikely.

For what I think, it need to run like a quarter of the time in order to have significant savings to offset the higher noise and hotter operation a larger compressor create.

So my question is, do we really need a bigger chiler than what it required to chill our tanks. I am not suggesting that we go for a smaller on. just something that's rated or slightly bigger if a lot of lights. Penny for your thoughts.

[nqh71]

Had the same thought before too... Can somebody care to explain further if it does save the $$$

[riot]

yeah I'm thinking along the same line too. However, if you are sitting watching your tank and your chiller turns your tank area into a sauna, some people dont mind paying for this if it means their chiller turns on in short bursts.

[tigershark]

I'm 100% agree with Tanggy, the same concept applied to air con where a bigger unit will need lesser time to cool down the temp of a room compare to a smaller unit. However, the bigger unit will have a higher power consumption, eg;

Lets assume that there are 2 aircon unit in a room and both is equally efficency at their wattage rating...

a) A 1000W aircon unit run 1 hr to cool down the temp from 32 deg Cel to 22 deg Cel.

power consume= 1000W x 1 hr = 1KW

A 500W aircon unit needs to run 2 hrs to coll down the temp from 32 deg Cel to 22 deg cel

power consume= 500W x 2 hrs= 1 KW

in the end of the day, both aircon unit are consuming the same amount of electricity... However, aircon B should ave shorter lifespan due to higher usage compare to aircon A.

[CalciumReef]

what chiller do you base it on?different chiller has different chilling rates too even though the H/p is rated the same

[Tanggy]

From what I have read in the threads. I had seen quite a few eg of people using RR and TR and running for 2-4hrs to drop temp by 1+ deg. assuming this is true, Like what I said unless the smaller chiller is insufficient to chill the tank ( like run for 20 hrs and hardly can maintain desired temp) but if a half horse runs for 12 hrs, a 1.25 have to runs less than 4hrs a day just to match the power needs.

As for the house aircon example, this is different, not unless you never switch them off (like our chiller) a house air con need to cool air which is a bad conductor and a drop of 5-10 deg is desired in a short time.

[Golf]

Hey !

I tends to agree with Tanggy...sounds very logical and as a matter of fact, it had to be pretty true.

I think our dear friend, Wei Loong posted his analysis on his 1.25HP Titanium Chiller...on his 4ft tank (combined with PL + 250W MH). It took about 10hrs running time...which means about 40% of the time, it is consuming all electricity.

Personally, I use a Resun CL 300 (1/10HP) chiller to cool my 4ft tank to 26deg.C. It is under-powered...but actual temperature is around 26~27deg.C. It runs about 50% of the time...electrical bill- hardly make any obvious dent on my PUB bill man.

Problem - it is noisy lah as compared to Teco.

Just my personal comments...thats all!

Cheers to all , Golf

[Blenny]

maybe Dr Chill should have a look at this and comment. After all he is the most qualified to clear this cloud here.

Dr Chill! Dr Chill! Help is needed here.

[Tanzy]

Bigger chillers give a more stable water temperature. They can pull the temperature down faster. My chiller hysteresis is set at 0.5­°C. Realistically, water temperature range is about 1°C. My 1.25 TiR runs for an hour or so each time it starts when the lights are on. The interval between is about 1.5-2 hours. My previous Teco 0.5 RA680 had to work for more than 2 hours with similar intervals between on/off.

Although purely anedotal as no real measurements were made but I am definite the TiR is running for shorter period of time and when I view my tank it is way quieter.

[Tanggy]

If what weileong say is true, think of it, 10 hours a day at 1100watt = 11kwh.

So for example is a 0.5 runs for 24 hrs a day and can maintain the temp (worst case la, unlikely unless super powful light and very big tank then have to use very big chiller) -

24x440watt=10560watt=10.56kwh

So if a 0.5 hp chiller can chill, even if it runs 24/7, it will still consum less power. But thats provided it can chill the tank la. if it cant then still have to get a bigger chiller.

I have been monitoring my 0.5HP teco on my 180 gallon. with sump minus the rocks,sand etc got total of around 190 gallons of water. With all the lights (2x250mh, 2x36watt antinic and 2 x 36watt pl in sump) the chillers runs for bout 2.5hrs and stop for 2hrs. with the lights off, runs for <2hrs and stop for 3hrs. Estimated runs for around 11-13 hrs a day. So if I go for a 1.25HP, it needs to run for total of <5hrs daily just to see a slight drop in elect bill. Will have to run like <3hrs to see sinificant decrease in elect.

I was just wondering how come weileong need bout 10hrs to chill a smaller tank?? When his chiller is 2.5 times the size of mine?? is it he got the wrong setup or too much heat to chill??

10hrsx1100watt = 11kwh

at $0.16 per kwh it will be 11x0.16 = $1.76 a day

$1.76 x 30 = $52.80 per month in elect bill.

asuming mine runs for 14hrs daily (worst case)

14x440=6160=6.16kwh

$0.16x6.16 = $0.99/day

30x0.99=$29.70/month

So you can see a sinifficant difference in elect bill but I have a bigger tank and more water to cool?? Theoritically should not be the case.

So I also dont know. can any bros with a 1.25 but running shorter period let us in on the running time??

[Tanzy]

You can't make the chiller run 24 hours. I had a RA240 before on the same tank and it was going non-stop. Infact, the water temperature was gradually rising to 28.5°C when the lights were on.

[CalciumReef]

His mh is 3 inch from the water.On top of that he has quite a few powerful pumps in the sump, contributing to the heat.

[Blenny]

have been monitoring my teco 680 on my 6x2.5x2.5 FW planted tank with 3x150w mh and iwaki pump today. Lights was turned on at 1700 hrs and chillers is still not turned on. Temperature recorded on chiller is 26c.

Today is cooler but in normal days. chiller needs to work about 30 mins to reach 26c before shutting down for an hour or so before turned on again.

Am still why is there so much difference?!?!!?

[Tanggy]

I am not saying making a chiller runs 24/7. If a chiller need to run 24/7 means that it is unable to chiller the temp. I am just stating if a chiller can maintain the temp, even if it runs 24/7, it will still most likely be using less power.

[Tanggy]

Not suggesting people get smaller chiller than rated for their tank as that would not be able to chiller. I state smaller as in enough, rated for tank size. as compared to over sizing.

Just trying to get actual fact whether does bigger chiller save power or waste power. Of cos if very big tank and like 3x400watt MH one would need such a big chiller la.

My 2x250 MH is around 3-4 inches above the water too.

[weisoon]

Just thinking about those air-cons used to cool our rooms. I had a very old multi-split 4 to 1 with single compressor. Everytime any 1 room or all rooms cooling unit is switched on, the compressor starts. The air-con man said that the newer compressors have twin compressor and with inverter, meaning that if only 1 room needs to be cool, then only 1 compressor switch on, else both compressor will come on, this will result in savings if quite often only 1 room is needed to be cool.

Basing on this, maybe there is a optimum HP for a certain size of tank and anything over power will consume more electricity because although chiller will run shorter but it will run at full power, unless the chiller has twin compressor, or better still, inverter technology.

Just some thoughts

Cheers.

[AlfaRomeo]

Had a first run-in of my 1.25 TR chiller for my 6x2.5x2.5 tank.

The chiller dropped the temp from 26 to 25 in about an hour and it took 4 hours for the temp to reach 26 again.. this is with 3 x 250W Mh on..

Guess today is a cooler day and my place is very very windy so the temperature increase rate is super slow..

I think there are a lot of factors involved when we are evaluating chiller performace.. no of pumps in the water, wattage of MH, distance of MH lights from Water, ambient temperature, circulation of surrounding air etc etc..

[Tanggy]

So theorically, would 2 0.5 hp chiller set at 1 deg difference be more efficient than running 1 big one?? So let say one set to start at 1.5 deg increase and the othe at 1 deg. then one would start later while one start first but stop earlier?? Or something like tat.

[Tanggy]

Alfa, your one bo pian, so big tank, 0.5 definitely not enough. must be like 1hp or 1.25.

[Tanggy]

Wonder if someone can come out one that is twin compressor!! Dr chill, can consider?? ke ke.....

[weisoon]

If you set one at 1 degree diff and the other at 1.5 degree diff, then only the 1 degree diff chiller will run and the other will not even start at all as temp will not go beyond 1.5 degree diff as the first chiller already kicks in and cool down the tank. IMHO. Guess at the end of the day, not adviceable to over size unless there is a need.

[RockyBoy]

The size of the chiller only helps to speed up the cooling process, the bigger the size, the faster the water reaches the setpoint temperature. It is good to get the correct size of the chiller so that the chiller will not underwork nor overwork. The amount of electricity consumption is greatly depend on the heatload absorbed by the water due to the lights and pumps and also the efficiency of the chiller.

[Tanggy]

Thats exactly what I am trying to say, do we need to oversize the chiller we get. Cos I have be told by every LFS and most of the people I have ask. Thus would like to shed some light to this myth to set the record straight ma.

Maybe it's just typical singaporean style. Kiasu syndrome!! Just buy the biggest one. Better safe than sorry! ke ke......

[Achilles Tang]

Guess from my non-professional opinion:

If you have a heavy load to pull.... you use a truck to pull it. You don't attach 20 scooters to the trailer.... sure...they'll do the job but not as efficiently as a truck.

You'll probably burn enough rubber before you get enough momentum to move the first metre!

[Tanggy]

true. but on the other hand, if you have a sofa to move and you get an 18wheeler to move it, also waste diesel and the cost to rent the truck when renting a van would do the job quite efficiently.

Eg. if a 1.25HP chiller is enough for a 6x3x2.5 tank with 1600watt of light, do a 4x2x2.5 tank with 500watt of light require the same size chiller?? Not say the 6ft should use a 0.5 as would not be able to cool but can a 0.5watt cool a 4ft??

What I am trying to point out is that does it make economical sense to buy sure a big chiller for a small small tank when asmaller chiller can cool that small tank but at a slightly longer time?? does the shorten period of cooling time justify the power cost involve.

a 1.25HP chiller and a 0.5 chiller does not really make much difference in price. probably 2-300 more. not much if you are already spending 1k+ liao. just that the power comsumption is 2.5times more and the noise and heat level increase also. But that's just my personal opinion la. If got plans to upgrade to bigger tank or stronger lights, of cos better to buy bigger chiller.