solar air power

[thirteen]

I am looking for a soler powered air compressor. I am filling one tank then using it to preasurize the other tank on demand air regulated type of system.  Gas is becoming to much to use.  

[thefinis]

Expensive power(solar) and inefficient use of power(air compressor)

A very small unit that feeds a large tank at a fairly low pressure might be workable.

[Vtbsr]

What are you using the air for? If it is for power tools how about a gas engine powered air compressor.

[thirteen]

I preasurize a large air tank 2000g and when I want water at the house I open a valve and preasurize the water tank which forces water around the house. When not in use the tank fills with a small trickle from a spring maybe one /half gal a minute at the most but 24 hr a day.  I use a gas powered compressor now. I am 51 miles to the nearest town and if I stay up during the winter the is 3-4 months of limeted snowmoble travel only.  

[Countryboy]

Use gravity and install the water holding tank higher than the faucets.

Why do you think towns have tall water towers?

Why do you think the water tank for toilets is higher than the bowl?

[thefinis]

You are only needing low pressure(30-60 psi)if the tank is on the same level as the house. After thinking about this and the amount of air you would need if this is the main thing it is used for then a dc conversion of a small unit is very doable. A battery bank can act as the storage and only kick the unit on when needed for the water system pressure and use it as a dump load when batteries are full.

If you are going to set up a hydro unit then this is a little redundant just get a small ac compressor and run the air pump off peak.

Good luck

Finis

[ghurd]

I have put quite a lot of thought into this myself, and hope more people jump in with ideas.

So far the best I can come up with is...  (Not sure if its a good idea)

Solar, wind, or hydro charging the batteries.

A dump load controller with a timed dump, like Chris G's Homepower circuit, but set to a much longer dump time. Maybe 3 minutes?

The dump load is an inverter.  The compressor is pluged into the inverter.

The batteries get full, the compressor comes on.  The batteries should have a long life because they are almost always full.  And if the pressure gets low while the sun is not out, it can be switched on to add pressure.

I have a feeling very large air and water tanks are a good idea.

DC compressors are either VERY expensive, or junk toy tire pumps.

Small AC oiled compressors that will last don't seem to be made.

That leaves me thinking refridgerator compressor.  I don't know about them and there isn't a lot of info floating around.  I guess there are 3 kinds, but only 1 is good for an air compressor.

Best guesses... They don't take a whole lot of power, but only move 0.5CFM at about any reasonable pressure.  Should move 0.5CFM at 125PSI with 150W, maybe less???.

Possible troubles, they may run hotter with a cheaper inverter, and they need a large upright pipe with baffles at the air output to let the oil cycle back into the compressor.

Two pop-offs would be a good idea, I was told 'fridge compressors can pass 300PSI easy.

Very rough math (nowhere to really start), I get a 50W PV with 2 hours of insolation will move 110 gallons of water per day.  As long as the system doesn't need opened and repressurized. Double the PV watts, double the water.

G-

[RP]

Anytime you compress something (like air), part of the energy turns into heat.  That is, the compressed air is hotter than it was before being compressed.  After it cools, the pressure reduces to lower than it was when it was hot.  Since the purpose is too move water, why not simply use the solar power to pump the water directly?

Dark periods could be handled with a battery system or alternatively, use a ballast pressure tank (with an air bladder) and use the pump to pressurize it during the day.  This is how most well systems work and the pump only kicks on when the pressure in the system falls below a certain point.

[TAH]

It seems to me that the best way to do the water would be to add a pressure tank like a standard well system and then use a shallow well pump with a presure switch to feed water when needed from the large tank. If you want simpler get a motor home pressure pump. They work good and run off 12 VDC. You just add it in series in the pipe to the house and power it off batteries that have some solar panels charging them. They turn on when the pressure in the pipes drops. This would require far less power than almost any other way and is easy. It wouldn't take much to figure out many solar panels you would need if you knew how much water you use.  

[thirteen]

thanks for the onfp.13