Using chilled air to cool water

[saseafoods]

We are looking to chill large volumes of seawater using chilled air. Does anyone know of an equation that may help us work out how much chilled air would be required to cool the water?

To give you some background to the project, we are an aquaculture facility pumping approx 800L/sec of water throughout the farm. We are trialling the use of compressors and diffusers to increase oxygen levels in the water. However, we would also like to reduce our water temperatures by 1-2C during the middle of summer. One thought was to use chilled air (-20C) instead of ambient air.

Does this sound feasible? Any suggestions?

Cheers,

Ben

 

[russ_watters]

Welcome to PF.

It would be more efficient to use chilled water and heat exchangers to chill the water. But it would be even more efficent to use evaporative cooling (cooling towers) to do it.

What are the initial water temperature and night-time air temperature and humidity?

 

[saseafoods]

Thanks.

Peak water temperatures reach 23C, although there is very little fluctuation throughout the day (1C max). Daytime air temperatures can reach 40C with night temperatures as cool as 10C.

Heat exchangers have been investigated but are cost-prohibitive for the volume of water we are using. As we are aerating the water in this trial, the idea of using cold air instead of ambient was one that was thrown up as a cheap way of possibly cooling the water. Do you think this would work?

 

[chill_factor]

if you use air blowing, the primary cooling would be from increased evaporation rates instead of heat transfer from water to air, so cooled air should not have significant advantages over ambient air while being significantly more expensive.