Backyard Aquaponics
A place to discuss aquaponics

How come train engines can stand idling in the yard day and night sometimes days on end

Because when they're not sitting around idling they're loaded right up getting a workout.

You don't need to load a diesel up all the time, but you do sometimes.

It's not an issue if you're running at even 25% - 30% of capacity; especially with an air-cooled diesel engine.

Regardless of the age of this thread I feel compelled to bang on about stuff as usual.

One thing you can do with excess energy or off peak energy, is to heat or cool a stinking great body of something, then run air conditioning conduit through it when you need it later.

Radio National (Australian government radio that I listened to for 12 hours a day and is responsible for a lot of my education ) did an article around 20-30 years ago on a USA university that used off peak power to heat or cool an olympic sized swimming pool of water so that it was simmering or freezing at night, then used during the day for air conditioning.

What was I talking about again?

I had this idea about lifting a really heavy object like 10 tons of steel (1 m x 1 m x 1.3 m) inside a cage with surplus electricity and an electric geared motor. Then letting it descend slowly while being hooked up to on demand geared generators. It would be a lot more compact than pumping water especially if you don't have it.

Pete.

And it could be made to look steam-punk as well, which is always a positive feature.

I'm sorry to burst your balloon, but where are you going to find a 10 ton lump of steel? It would cost a lot of money if you can get hold of it.
If it is descending very slowly, much of your potential energy will be lost through the gearing up process to make a generator spin fast enough to generate electricity.

How high up are you going to lift it? It would be dangerous to lift more than say 5 m, even if you had an extremely strong (ie expensive) cage to contain it, but even then you could only store a rather small amount of energy, much less than a small 12V car battery. Even if you dont have it, 10000l of water will cost a lot less to buy than 10000kg of steel!

If I've calculated correctly, and you had no losses, 490kW for 1 second, or 136W for an hour - 11AH at 12V. Accounting for more than 50% losses through the gearing, both up and down, you are going to have to put in 4X the energy that you get back, so ~275W for an hour to lift it, and <70W for an hour out.

I think you'd be better off buying a battery, a solar panel, and a charger!

Is there a lot of potentially stored energy in a rainwater sized tank with 20-40m of height difference to the discharge point?

Having silly ideas... Not hard to create that height difference at an average house, without putting the tank on a whacking great big stand, if you think outside the box.

I'm in the middle of (very slowly) putting together a pumped stored hydroelectric system, and have 85m of head with 23000 litres of water, and expect to be able to recover about 3.5kWh of energy from that, of course using more than that to get it up there, but at no cost.