Should I Get A Chiller?

[mike_danger]

Hi all,

Having real problems with the temp of my tank, the worst was 30 C!!

At the moment I am using a fan to keep the temp down, but I don’t like this as it is causing massive evaporation which in turn is costing me a lot in RO water (have to buy it as I live in a rented flat so can't set up my own RO).

I have been reading through the posts and I think my best option is to get a chiller. I am hoping to get one for under £200.00 (posted link below for ones on eBay, what do you think of them?)

I am hoping to fit the chiller under my cabinet, will this be OK? Will I need to provide a lot of ventilation for the chiller as I’ve heard they get really hot and make the room really hot, is this true? I also don’t want dripping walls. Will I still get a lot of evaporation with the chiller? And Finally is there any hidden things I should know about chillers, ie costly to run, need regular mantance?

Many thanks, Michael

Chillers on eBay:
http/cgi.ebay.co.uk/CHILLER-COOLER-FOR-A...1QQcmdZViewItem
http/cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...AMEWA%3AIT&rd=1

 

[SkiFletch]

Chillers are like air conditioners for your tank. You pay a LOT to run one usually since there is so much latent heat in water (probably more than the cost of RO water), and they heat up the room a lot. Cooling in a quality chiller is limited to the water heat exchanger so you dont really have a problem with condensate on the walls, but you do have to remove that waste heat some how. A chiller running in the same room as the tank will cool the water down but heat the room... If it were my tank, I wouldn't buy one and look into line-piercing fittings to install an RO unit. Prolly cheaper

 

[N1z]

I must admit i thought about one once too, mainly in the hot days. But really i tried a fan also and didnt work so most times the temp is at 28 deg but 30 on hot days with no windows open due to no one is in! but there are no signs affecting the fish nor the corals.

 

[MHunt]

You could always swap the washing machine fitting if you can get to it when you want to make the RO. the fittings are the same i think!

 

[mike_danger]

Hi all,

I got a bit impatiant last night and bought this one off eBay..

http/cgi.ebay.co.uk/CHILLER-COOLER-FOR-A...1QQcmdZViewItem
[url=http/cgi.ebay.co.uk/ws/eBayISAPI.dll?

He seler told me that it wont heat the room up, and it is smal enough to fit under my tank in the cabinet.

I hope its ok

Michael

 

[SkiFletch]

Well mike, it will work and your tank will get cooler. At a mere 1A draw its gonna take some time to get it cool enough to get your tank down to temp. I could figure it out roughly roughly for you if I knew the tank volume, current temp, and the temp you want it to get to. Then you could estimate how much energy costs would be. At least you got one with a titanium heat exchanger, those dont corrode very fast at all so it should run for a few years. During the winter months I'd disconnect and drain the chiller. Also, heed the warning at the bottom of the seller's auction: Set the chiller in place and leave it for 24 hours before you turn it on. The refrigerant needs to settle before the compressor can operate properly.

 

[mike_danger]

Hi Skifletch,

Thanks for your help. My tank is 190L, but with displacement theres about 160 litres in there. At the mo my tank is 30 C, and I want it down to a good temp maybe 25/26 (would it be cheaper to run the tank hotter?). If you could work out how much electric it will use I would be very greatful.

It is not very hot here at the mo, so I am thinking im gonna need the chiller on all year around, but i take it not using it winter prolongs the life? So heres me hoping for a cold winter lol. I didnt realise chillers had only a couple of years life on them, thats a bit annoying!

If you know any more info for chillers I would be really greatul, as I am a newbie to marine let alone chillers lol.

Michael

 

[SkiFletch]

I'm going to ignore evaporation here with this calculation for a sort of worst-case scenario. In reality evaporation is currently in equillibrium with your heat added so ignoring it is feasible. So you want to cool 160L (aka 160kg's) of saltwater from 30 to 26C. Some useful quantities to know are the specific heat of saltwater (5018J/(kg*K)), the delta T (4K), and the mass of water (160kg). So the second law of thermodynamics says Q=MCpDeltaT. So heat transfered (Q) = 160kg(5018/(kg*K))(4K). So you need to remove 3211520 Joules of heat. Converting that to a useful energy medium thats 892 watthors (thank you onlineconversion ). So at 220V 1A thats 220watts which would require 4 hours of constant chiller operation. Now that would be IF the chiller were 100% efficient at removing heat. Compressor chillers for aquaria are however at BEST 70% efficient, so you'll actually only deliver 154watts to the water for about 6 hours of chiller operation initially.

Its basically 1 kilowatt hour just to cool the tank initially. Then the forumulas get more complex to calculate the equillibrium of the tank. Suffice it to say that your chiller will prolly run about a KWH per day to keep the tank cool in the summer months. So 30 KWH per month around where I live is only about $3/month, but something tells me that since you dont live next to niagara falls your energy costs are a little higher. Check your local bill, or maybe someone in the UK can chime in on what your electrical costs are around there per kilowatt hour.

Sorry about getting long-winded there, I work in a thermal cooling laboratory and I just get rolling sometimes . You should try calculating how much energy it takes to cool a 167,000 gallon pool from 29C to 5C and then keep it there... Anyway, I hope that all makes sense. Removing the chiller in the winter will make it last much longer. Problem is, salt water is horribly corrosive and even the best titanium cant last forever before it'll be eaten away.

Just multiply 30 times your Kilowatt hour cost and you should have the avearage cost of running the chiller.

 

[mike_danger]

Wow that was complecated, but very useful. Looking at my bill I think it will cost about £3.00 a month to ru,n, I dread to think how much my whole tank costs with filter, powerheads skimmer, lights!!

I will do some tests in the winter, turning it off, as you say it will prolong the life and save me £££££!!

Good news it has just turned up, so gonna set it up and let it stand for 24hrs.

Michael