HP per gallon for a chiller?

[JoJosReef]

Scanning the online vendors, the fraction of "HP" for a chiller that is appropriate for your tank size and situation is still a black box for me. All I know so far is that the JBJ 1/15HP chiller is their nano chiller.

I assume the appropriate HP fraction for your tank is a function of the total water volume of the system and the expected ambient temperature (throw in humidity and air exchange for good measure), which I suppose could be used to estimate a BTU/hr requirement (???).

In any case, is there a rule of thumb for people buying their first chiller?

For ref, my tank is an 83gal DT with 1-1.5" sand bed, about 40-50lb of very porous live ocean rock, and a 29gal sump. Temp is a problem on the weekends in the summer when the office A/C cuts off and office temps can go over 100, although most commonly in the 90s.

Thanks!

 

[bubbgee]

I'd go with 1/4 hp used. here's some info from MarineAndReef.com

 

[UncommonSense]

Scanning the online vendors, the fraction of "HP" for a chiller that is appropriate for your tank size and situation is still a black box for me. All I know so far is that the JBJ 1/15HP chiller is their nano chiller.

I assume the appropriate HP fraction for your tank is a function of the total water volume of the system and the expected ambient temperature (throw in humidity and air exchange for good measure), which I suppose could be used to estimate a BTU/hr requirement (???).

In any case, is there a rule of thumb for people buying their first chiller?

For ref, my tank is an 83gal DT with 1-1.5" sand bed, about 40-50lb of very porous live ocean rock, and a 29gal sump. Temp is a problem on the weekends in the summer when the office A/C cuts off and office temps can go over 100, although most commonly in the 90s.

Thanks!

There is a calculation for this actually!

The factor you need still is the maximum temp reduction desired…

if it’s 110-120 degrees outside on a Thursday, never really cools down below 80 overnight, then is the same blistering 110-120 degrees Friday, and the weekend… which isn’t unheard of in our sunshine state…

In such conditions; the sheer amount of “heat soak” through the entire building will mean the walls are radiating 90+ degree temperatures even into the night!

So, let’s assume the tank has to stew for three nights at up to 100 degrees air temperature in a worst-case scenario…

You probably want your water at or below 80 degrees… to get a 20 degree cooling difference from tank temp to air temp; the math I just did came out to roughly 3,700BTU… this doesn’t account for several factors, and is calculated off 110g water volume.

I do see that JBJ has a 1/3hp unit rated at 4,000BTU!

Possibly consider insulating any panes of your tank/sump not used for viewing to improve chiller performance? Or, a thermal cover for hot weekends so the chiller isn’t working so hard? — it’s a pretty extreme operating scenario!