Backyard Aquaponics
A place to discuss aquaponics

Imagine a cold winter's night,
Dinner is served - Barramundi, potato, sweet potato with herbs and salads, all from your AP system, picked, prepared and served on the same day.
Without breaking the bank on heating bills or causing pollution.

This is NOT science fiction!

If you can use a diesel generator to supply power for your home, why not use the heat released in cooling the engine, which is normally wasted, to heat your greenhouse, and the fish ponds.

All engines (petrol or diesel) convert only part of the energy of the fuel into power at the crankshaft. At least 60% is used in creating heat.

For a diesel engine a good rule of thumb is that

• ~30% is crankshaft power,
• ~30% is heat removed by the cooling system and
• ~30% is heat in the exhaust gases.

The other ~10% provides noise and vibration.

How can we make use of this 60-70% of the energy that is currently wasted? This amounts to around 10KW of heat power for a 5KW electrical generator.

Direct heating.
If the engine is air cooled, the cooling air can be drawn from and sent back to the greenhouse.

Heat exchangers.
Liquid/Liquid -

• If the engine is cooled using a liquid coolant, a liquid/liquid coolant can be used to take heat from the engine coolant and eliminate any cross contamination.
• The diesel engine oil can be pumped thru a liquid/liquid heat exchanger to recover heat from the engine oil also.

Gas/Liquid -

• The engine exhaust can pass through a gas/liquid heat exchanger to heat water.
• Spent cooling air can be passed through a car radiator to heat water.

As long as the engine is allowed to operate at the correct engine temperature, this heat recovery will not adversely impact on engine longevity.

So, how can we run this with no pollution?

Well not quite NO pollution, but significantly less greenhouse gas emissions will be generated by using biodiesel and/or straight used vegetable oil instead of petroleum diesel.

Anyone care to set up a system to test my theories?

Tony

If i had a Diesel genny sitting around i would!

have just been looking on ebay

I live in a semi-rural setting and my nearest neighbour ids 500M away, so the noise of a "quiet" diesel (75dBA @ 5M) should not cause any disturbance to them. I doubt that any AP'er living in suburbia would be likely to get away with operating a diesel genny, unless he were supplying the whole neighbourhood with barra and veggies

What about ya Monya, I've seen a pic of your geny and I recon You could heat a few fish tanks with that little baby!

I already supply my neighbour with broadbans a few veg should sweaten the deal

Besides reverse cycle split systems sit at around 60dB, and i've found a 6KVA genny running at that noise.............

I'm sure a exhaust heat exchanger might bring that level down a tad if designed right

Sure it would work and be a good use of wasted energy, but who runs a gen all the time?

point being maybe you could run a small gen to run your AP setup and use the 50% wasted heat to heat your tanks and GH

Please keep the banter going, You are giving me more ideas.

Probably more effective to run the generator when the power is needed most and turn it off when not needed. It is amazing how much heat can be stored in 5KL of water.

What about using LPG for the fuel? Obviously it will need to be a suitable genny, but I've heard of people converting small engines to LPG/Propane fairly easily. It's cheap, if you're already using gas for cooking/hot water you've probably already got a source of it, if not, you could use 9kg gas bottles.

Just need to find a renewable supply of methane...
....bring on the composting bog!
Collect methane and bio energy to burn...time to eat more!

an excerpt(?)
We look at how the bacterial community structures change over time in the system, and relate those to environmental parameters such as pH and volatile fatty acid concentration," Mr Dearman said.

This enables the volume and rate of exchange of the nutrient to be adjusted to maximise methane production. While significant levels of methane are generated in the early phase, production reaches its peak after about two weeks.

The methane yield is approximately 300 litres from every dry kilogram of food waste, with the methane present in the biogas at concentrations of up to 75 per cent.

Problematic gases, such as the notoriously smelly hydrogen sulphide, can be kept to minimal concentrations, Mr Dearman said.

'Recalls blue flame tests as a youngster'
C1

Hehehe

I was thinking last night/early this AM about the possibility of using a waste oil boiler to operate a steam engine, which enter would provide mechanical power to operate an electric generator. You get the benefit of heat from the boiler for your home, the greenhouse or AP system, the steam engine, and maybe enough steam to operate a Calliope!

Kevin

I find some sites that cover steam engines and boilers. The first one is from Goolwa, S. Australia.

http://www.strathsteam.com

http://www.tinypower.com

http://www.pioneertelephonecoop.com/~ca ... Ehome.html

http://home.earthlink.net/~dlaw70/12stmng.htm

I also found some for solar heating that I thought you might want to check out;

www.bigginhill.co.uk/solar.htm

http://www.builditsolar.com/Projects/Sp ... eating.htm

Kevin