-=>Quoting Gary Collier to All <=-
GC>I would appreciate some advice regarding a project I am pursuing.
Go ahead. We're friendly, damnit. [grin]
GC>I intend to retrofit a hot water heater to burn wood and I need a
GC>pump that will pump the water from a storage tank up 15 to 20 feet
GC>and through a copper pipe heat exchanger(aluminum fins) placed in
GC>a forced air system (formerly a functional Heat pump). I intend to
GC>use gravity to return cooled water in a closed loop to the boiler.
If you insure that air is kept out of the line, you can move the
water easily with most any pump.
GC>I have several options for a pump, including a sump pump that
GC>currently pumps a head of at least 10 feet(more potential) now,
GC>but I have concerns for heat transferance to the attached motor.
GC>Is heat transferance in a metal jacketed sump pump a valid concern?
Yes. A submersible pump will not last very long at continuous duty in
hot water. With hot water applications, the motor needs to be
separate from the pump, ie. it must be air cooled.
GC>Can a water pump such as from a chevy citation (seperate
GC>housing type) provide 20 foot head?
Nope. It is designed to move a lot of water at lot pressure, < 5 PSI.
GC>Is their a larger capacity water pump and external housing (sans
GC>motor) available in an automotive wrecking yard?
I can't imagine one. Farm equipment yards may be a possibility.
Industral equipment, better. Do you live near a large city?
GC>I have several 110 and 240v motors available, but would like to
GC>know if a 12 volt motor could be used here, as I intend to make
GC>this system easily dismantled and moved offsite with the potential
GC>to be solarpowered.
Motors are rather power intensive. You will probably need at least
300-watts (1/4-HP) to move enough water. And, since you are using it
in conjunction with your central air, you will need to power that,
too.
GC>In this scenario, the pump would be belt driven. Can I utilize
GC>galvanized pipe from the storage pipe up to the heat exchanger or
GC>will their be interaction with the copper?
Yes. But you can purchase special fittings (usually brass) to isolate
the two and prevent corosion.
GC>I intend to have a switch/valve that can activate upon pump shut
GC>off, to drain system when temperatures drop below freezing (to protect
GC>copper heat exchanger), but do I have to use antifreeze for rust
GC>prevention being that it is a closed loop system??
That would be a good idea, plus the glycol will allow you to transfer
more heat energy.
GC>Will limiting flow for better heat transfer at the exchanger
GC>create a strain upon the motor, or is the flow rate inconsequential?
Move as much water at the motor rating. Use no restrictors.
GC>I know the concept has too work...lennox is starting to make furnaces
GC>utilizing fast recovery gas water heaters with aluminum heat
GC>exchangers, but they plumb into the hot water line of the house, an
GC>approach I am not comfortable with for my application.
Interesting. You say they steal heat from the water heaters to boost
their BTU rating?
GC>How high can I pump water with these types of pumps?
Not familar with that, but if you are burning wood to make heat, why
not simply vent the heat from the source directly through the house?
I helped a friend move his return vent to where his wood stove was
located. The heat rising from the stove gets circulated throughout
the house. No water, no pumps, easy to do. My kind of project. [grin]
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