All times are UTC + 8 hours




Post new topic Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Jul 16th, '18, 15:29 
Offline

Joined: Jul 16th, '18, 14:26
Posts: 1
Gender: Male
Are you human?: Yes
Location: Colombia
Myself and a buddy of mine are currently starting the design process for a small scale/Pilot project, partial re-use system for raising Tilapia.

He recently purchased a farm in a tropical region of Colombia which has a year-round stream/waterfall flowing right through the property. We have been discussing the idea of trying to take advantage of the stream by building a pilot project for an 80% RAS//20% flow-through to get a better idea of the economics behind it before entertaining the idea of anything commercial.

The one area where were getting stuck is coming up with the most efficient way to control the water temperature in the system.

The temperature of the incoming flow is around 70-71 degrees F, (We've been checking it multiple days at different points throughout the day). Considering were located right on the Equator, There isnt any seasonal changes in ambient temperature...Were looking at year-round avg daily highs of 82-85 degrees, avg nightly lows of 61-63, (overall avg temperatures right around 71 degrees throughout the year.

We are trying to figure out the most efficient way possible to keep the water temps right around 75-77 degrees consistently throughout the day. I've spent all week trying to familiarize myself with the Thermal aspect of water temp control but I just keep going around in circles with all of the available ways to heat the water.

Were set on starting with 3 tanks, 2000 Gallons each with a replacement flow-rate of around 7 gpm, and the recirculating rate of 27gpm. The tanks will be installed outdoors but we are not opposed to putting up a greenhouse/plastic coverhouse over the tanks but I cant imagine that alone making much of a difference considering there wouldnt be any insulation.

Immersion heaters work, but I have to believe there is a more economical way to taking advantage of the climate here. Granted we will have to regulate the temperature through-out the year...we are realistically only a few degrees away from Optimum growing conditions. We realize we will not only have to maintain the temperatures in the tanks, but also attempt to raise the temp of the incoming replacement flow a few degrees to try and keep things consistent.

So far i've looked into In-line heaters for increasing the replacement flow temps, immersion heaters for keeping the growout tank temperatures within range, Heat exchangers/pumps to recover some of the heat from the 20% that is exiting the system. But realistically, I cant figure out which might be overkill, in-efficient, or theoretically incorrect lol Also, would incorporating a Solar heating system be complementary? How do I even begin the process of sizing it considering our production parameters? its usually around 75 degrees by 9am, 85 degrees by noon, and 75 by 5pm, so there's about 8 hours throughout the day where ambient temperatures are just perfect.

Sorry If im being redundant, thermal energy is just not my cup of tea. But if anyone can point me in the right direction, any insight would be appreciated.


Top
 Profile  
Reply with quote  
    Advertisement
 
PostPosted: Jul 16th, '18, 17:53 
Offline
Bordering on Legend
Bordering on Legend

Joined: Feb 8th, '17, 18:03
Posts: 283
Gender: Male
Are you human?: YES
Location: UK East Sussex
A method many people seem to use is circulating water through black tubing in direct sunlight. Sensors can be used to increase/decrease flow through tubing according to temp requirements.

Are you planning on using bio-filtration and growing plants? If so then you may find the system temperature fluctuates diurnally as grow-beds and filters absorb heat during the day and release heat during the night. If this were the case you could reduce overall flow rate during night and limit flow-through to daytime.


Top
 Profile  
Reply with quote  
PostPosted: Jul 17th, '18, 09:22 
Offline
Bordering on Legend
Bordering on Legend
User avatar

Joined: Jun 17th, '07, 12:53
Posts: 471
Location: Riverland Sth Australia
Gender: Male
Are you human?: Yes
Location: Riverland Sth Australia
Attachment:
Systems with heater.JPG
Systems with heater.JPG [ 183.29 KiB | Viewed 2257 times ]
First thing will be effective insulation so you don't lose the heat you have just put in . Black poly is a big help here in the cold seasons pic shows a trial on my system , this year I have clear plastic over the poly works much better , clear plastic is pinned down around the edges to stop our cold wind . Water is pumped through the poly controlled by a timer.

Another way or combination of both is part of your system in a "Hot House" , you don't have to lift your temperature much so shouldn't be too hard to achieve .

I know of a system locally that is under plastic all year but gets TOO HOT during our summer so im planning a combo setup .

My system will all be shifted around the corner to the right of pic as soon as im fit enough ,

Fish tanks and some biofiltration in a insulated shed , one third hot house on one end , two thirds shade house on the other end (aligned for sun track) so I can shut down sections through the seasons if required .That's how I intend to manage my temperatures .

Before I got my heater running again my system got down to 8 celcius

Maybe you can run your replacement water through a 1000 metres of black poly , some into system and some into a storage tank during daylight to provide the required replacement flow after dark .

_________________
My System
viewtopic.php?f=18&t=12070


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC + 8 hours


Who is online

Users browsing this forum: No registered users and 5 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

Powered by phpBB® Forum Software © phpBB Group
Portal by phpBB3 Portal © phpBB Türkiye
[ Time : 0.075s | 18 Queries | GZIP : Off ]