Any and all feedback greatly appreciated

Re: Any and all feedback greatly appreciated

First off thank you all for your feedback regarding this project.

Here are some answers to your questions and comments and way too much additional information:

BB:
“Everything is about conservation of power.” Boy I have learned this during this process. It’s kind of funny that when we are staying at the trailers on the property we use so very little energy – 12 volt lighting and fans run mostly only 2 to 3 hours at night. Hence the miniscule trailer solar system.

The air pump story:
The air pump that I have chose is the most energy efficient pump that will provide the required volume of air flow at the required PSI to aerate my pond to the depth that I need. What I failed to mention in my initial post is that the pond is 17 feet deep, and in order to get enough air flow down to that depth to provide enough air flow to a diffuser (actually two diffusers because of the volume of the pond) it requires a fairly significant air pump. The pumps originally suggested by the pond gurus gobbled up between 253 amps to a whopping 460 amps. This would have made my solar budget to through the roof! So I researched like crazy to get a pump down to 140 amps. Unfortunately none of the DC air pumps will provide anywhere near the air flow at the required PSI to overcome the depth of the pond. You mentioned mechanical beaters for aerating water, unfortunately they don’t aerate water much beyond about 4-5 feet deep which will not be sufficient for my pond depth. (I know probably way more information than you wanted about air pumps and ponds).

System losses:
Great information, thank you. As a side note when at a recent building show I spoke to several solar companies regarding the eventual home construction – they all said the same thing about panel derating by temp. I had found solar roof shingles that I thought looked nice but according to all the solar companies those are not advised unless you have no where else to put panels mainly because of the temp derating problem – something I had never heard of before. Fortunately I have 30 acres of property and there is a nice clear (of vegetation) crown of a hill that will get great exposure for the eventual house installation.

Evil batteries:
Thank you for the suggestion of the alternative brands. By switching to an AGM battery I can cut my budget for the batteries in half.

Shadows:
Fortunately at the pond site there is a rather large meadow area at the east end of the pond that doesn’t have any trees, power lines or anything else that will cast a shadow – aside from the occasional turkey vulture.


Roderick:
The pond story:
The pond was built sometime during the 1940s and was virtually never maintained. According to some of the pond gurus that I have spoken with without any intervention (aeration or filtration) most ponds have about a 30 year life. The saving grace with this pond is that it is spring fed which replenishes and renews the water. The pond is stocked with Large Mouth Bass, Green Sunfish, Blue Gill, Red Ear Sunfish and a few Catfish. In northern California we are not allowed to stock Tilapia. The pond is beginning to suffer from muck build up. Vegetation has formed a layer on the bottom of the deeper area’s of the pond that are not decomposing due to a lack of oxygen. Hence the aeration. Since the pond is deep I need to move a significant column of water up from the depths to the surface. The most efficient (from a water movement perspective) method to do this is to use diffused air to create a moving water column. The pond does not smell but is beginning to get clogged with vegetation and algae. I can (and will) use chemicals (there are several good herbicides that will not harm animal life) to kill back the offending plants but this is a short term fix. In addition during chemical vegetation removal you have to be very careful about causing an oxygen crash. Getting the muck to decompose will (purportedly) reduce the algae and Elodea and will reduce the likelihood of a fish kill due to an oxygen crash. Mainly the aeration is to help renew and rejuvenate the pond.

The pond is at the end of a valley and is the only year round surface water in the area. As such it is a great resource for wildlife and my intent with the property is to create sort of a natural wildlife sanctuary. I do fish but am not a hunter (don’t have anything against hunters but just never had the stomach for it myself). I myself have personally observed a lot of natural wildlife using the pond including: deer, mountain hare; red fox; turkey; squirrels; heron; geese; ducks, etc. In addition I have found (but never viewed) mountain lion tracks and bear have been seen on the property by a neighbor. The intent is to build a low impact energy efficient home and keep the property as natural as possible and just enjoy the wildlife and to fish on the pond.

Grid power:
No grid power exists on the property as yet. The nearest power pole to the pond is probably 1,200 to 1,500 feet. I may eventually have grid power to the house site which will be about 300 feed to the pond, so it maybe merely a waiting game until the house is built.

Running the system with out batteries:
Funny you mention that. This seems to be the most cost efficient solution. Although in theory it is better to aerate at night it seems like it will be way too expensive. Any aeration is better than no aeration so I have recalculated my system using a six hour per day run time that will only run during the day light hours and not on cloudy days. This reduced the budged to $2,465 – much more acceptable.

Jim
Thank you for the education, equipment suggestons and fine tuning my calculations. I have modified the excel spreadsheet to use an 87% inverter efficiency (instead of my 75%) and to use a 98% efficiency for the batteries and to use only 6 hours of summer isolation.


Revised calculations and budgets

Using Jim’s tweaks to my original calculations I have determined revised numbers as follows:

Here is the revised budget:
Kyocera KC-130 panels: 4 at $609 = $2,436
AGM 8A40 batteries: 5 at $329 = $1,645
Cables complete guess at $50
Controller Flexcharge DC Timer Controller: = $72
Inverter Excel Tech XP 600 = $531
Pole mounts TPM-2-KC130: 2 at $265 = $530

Total system cost $5,264.

Much better than my original $6,385. Still fairly costly.

A redesign
So back to the drawing board. Based upon all of your input and using the theory that any aeration is better than no aeration I decided to re-design the system entirely. Run the air pump only during the day and only for 6 hours per day. Here’s the resultant calculations. Load calculation: 140 watts x 6 hours per day divided by 87% inverter inefficiency = 966 daily watt hour divided by 12 volts = 80 daily amp hours. Battery calculations: 80 amp hours divided by 50% max battery draw down and divided by 98% battery inefficiency = 164 battery capacity in amp hours. Using a AGM 200 AH battery will require only 1 battery. PV Array Size calculation: 80 daily AH divided by 6 bright sunshine hours = 13.4 array current in amps. 13.4 divided by 7.4 module current in amps = 2 modules required.

Here’s the budget with only a 6 hour per day and day time only run times:

Kyocera KC-130 panels: 2 at $609 = $1,218
AGM 8A40 batteries: 1 at $329 = $329
Cables complete guess at $50
Controller Flexcharge DC Timer Controller: = $72
Inverter Excel Tech XP 600 = $531
Pole mounts TPM-2-KC130: 1 at $265 = $265

Total system cost $2,465.

If my calculations are correct that is much more affordable! Using a prepackaged windmill style aeration system is still slightly cheaper in total but has the problem that it simply will not run without adequate wind speed – I’m still researching this option. I am going to have to measure wind speed near the pond.

Any comments regarding the six hour run time calculations and budget?

Wow, I can't thank you all enough for your input and education - this is forum is truly a great resource. I will keep you posted on this project and others and will continue to participate in forum in whatever capacity I can (being a solar ignoramus I can’t provide any technical advise) but I will chime any on anything that I can. Because of the huge pending house project I am going to sign up some solar energy courses - not because I want to be involved in the house system design (I'll leave that to professionals) but merely because I feel like I need to understand how the system will work.

Sorry once again for the long winded post.

Re: Any and all feedback greatly appreciated

Mu uncle, in his younger days, had 3 fish ponds. He aerated his ponds with a small water pump, which sucked water from near the bottom and sprayed it up into the air, to fall back onto the pond.
Don't remember the exact details of the pump, but wasn't all that energy sucking.