Example ‘system’ cost in Montana, winter of 2017
Example ‘system’ cost in Montana, winter of 2017
Here in Montana 2017, I could create the following iAVs ‘system’ for under US$7000 (excluding ‘greenhouse’, labor, misc. tools and related supplies):
24 m3 of circular conical-bottom fish tanks with top-quality stainless steel pumps, current state-of-art regenerative blowers (aeration) with top-grade ceramic diffusers, SS fittings etc., and coupled to from 150 to 200 square meters of sand beds. 45 mil EPDM fish/food safe liners throughout. (all equipment Made in US, btw).
0.5 HP, 11,500 litre/hour at 1.5 m head 0.67 HP, 990 l/min @ 1 m depth
That’s between $28 and $35 per square meter (including a 50 m2 tank area) or $2.60 to $3.25 /ft2 with ‘top-shelf’ equipment and materials. Okay, so, maybe add $500 to include some misc. items and delivery costs to my mountain. Would be $1000 less if using in-ground (dug/lined) tanks.
At an average of under $3.00 a square foot, that’s considerably cheaper than any empty Rubbermaid (etc) bin/tub from China-mart. Seriously! How productive could that be for you? What’s the cost:benefit ratio of a flimsy polyethylene bucket on steroids? Where would you plug it in? BTW, un-faced Styrofoam™ (polystyrene) is $1.56/ft2 (alone) at the local Lowe’s (building supply megastore).
At 175 m2 of ‘grow-bed’, planted as single-stem tomato (or equivalent), that’s 700 plants/crop x 3 per year with a minimum of 6 kg/plt, for 12,600 kg/yr plus an expected 1500 to 2000 kg/yr of tilapia. [ 100-120 kg/m3/yr is possible (has been achieved) ]
PS: Ballpark cost for off-grid photovoltaic system to power the above equipment is in the $600 to $1000 range (PV cells, wire/fuse, charge controller and inverter) and without batteries (w/o aeration at night), base supports or installation. For 24-hour aeration (this example) add about $1000 to $1200 (for 500AH@24V for a 10-year +cycle/use life from lead-acid cells. Total overnight load in range of 35-45 AH draw (by latitude and season)… via the cheapest route … here … DIY)
- So, if it cost $1000 for panels etc with 25-yr+ life ($40/yr) plus about $110/yr for batteries. Effective annual cost $150.
- 24 hour load 13,5 kWh w/ 24/7 aeration. 13.5 x 365 ~ 5000 kWh/yr $150 / 5,000 kWh = $0.03/kWh. That’s about one-quarter of what grid electric rate is here. PV really has come WAY down in price over the past few years.
- Running cost (amortized PV) for 2 pumps (1hp @ 2hrs/day) is $0.045/day, $16.43/yr or $0.68 /m3/yr
-o0o-
Hai Mark…
Does it need this much big aerator…
One of my iAVs aerated with 20 lpm airpump @ 1m depth (2m3 fishtank(200 fish 50 kg standing density ) is that enough..?
Can we use a hemispherical shell type inground tank instead of circular conical tank (like a half coconut shell)
These type of tanks having an advantage of less foldings of geomembrane than circular tanks..Am I correct
No. minimum delivery depends on biomass, feed rate, temps and species. Tilapia don’t actually need any forced aeration to survive. Excellent growth performance (and low stress/high disease resistance) is a different subject. In the regenerative blower offerings, this size offers the ‘best bang for the buck’. That one could service more volume than I indicated – if and when that was desired. Significantly smaller ones are only slightly cheaper.
Not recommending the circular tank per se, just that MANY people prefer them – so I thought I’d price it in to this example. I’m not clear on exactly why. I’ve heard the claims, supposed benefits, and for actively swimming species such as trout, bass and salmon they have there place/use. But for tilapias or carps, catfish, perch not so much IMO. This is AN example, not THE example or a prescription. Only one example of thousands, costs only relative to here (in US).
Here’s a few more ‘examples’. https://iavs.info/backyard/iavs-easy/
I prefer a parabolic (catenary) profile with rounded ends for larger volume ‘tanks’ (concentrates solids plus convenient to access/manage and able to be subdivided for cohort staging.
Thank you Mark…..some times i had noticed the tilapia is gulping for air at surface. I thought it was because of low DO….
It almost certainly is. Won’t harm them but they also won’t be growing as fast as they could.
iAVs was designed to run without air pumps. While I would recommend supplementary aeration (as cheap insurance), we cannot know all of the factors associated with your circumstances and, as such, it is not possible to specify (with any certainty) any pump rating.
Suffice to say, when it comes to air, you need….enough! In making this observation, I’m not trying to be flippant but rather pointing out that every situation will be different according to the species, weight of fish biomass, feed composition and feeding rates, water temperature….and several other factors.
We can only attest to what we know and that information is on the iAVs web site. Everything else is subject to determination by the growing band of pioneers (like yourself) who are taking up iAVs.
Thank you gary…You already told me that through email but i was not fully satisfied. But now connecting openions of both of you something is sparking in my brain…