Would a solar powered pump work for a solar hot water heat system

[Curtis Jon]

I was toying with the idea to try and supplement my heat with some homemade
solar collectors. Something small maybe 5 to 10 4'x2' units. I was not
going to have a storage tank, just direct the heated water thru a hot water
base board type heater.

Could I just use a solar powered pump to circulate the water? It made sense
to me that when the sun came out and heated the collectors, the pump would
power up and circulate the water.

Thanks in advance,

Curtis Jon

 

[Derek Broughton]

I was toying with the idea to try and supplement my heat with some
homemade
solar collectors. Something small maybe 5 to 10 4'x2' units. I was not
going to have a storage tank, just direct the heated water thru a hot
water base board type heater.

Could I just use a solar powered pump to circulate the water? It made
sense to me that when the sun came out and heated the collectors, the pump
would power up and circulate the water.

That's the way to do it.

 

[SQLit]

That's the way to do it.

I disagree depending on the situation.

My flat plate collectors ~ 15 feet higher than the tank, could in the
summer time get pretty hot in Phoenix. If a cloud comes by the amount of
shadow could be enough to stop the pump from operating. This might create a
situation where the T&P valve might release. ( Mine did a couple of
times ).
If you decide to use solar cells to power the pump make sure that there is a
battery in the circuit to carry it over for the time clouds could interrupt
the production of electricity.
This concern I have is not a really big deal in the summer, it is in the
winter when the amount of sun is much less and my systems is on the edge
keeping up with the load. Of course if you do not care that the backup heat
kicks in .................

Besides the solar pumps and cells are a lot more expensive than running a
tiny pump on the utility, IMO

 

[Derek Broughton]

I disagree depending on the situation.

My flat plate collectors ~ 15 feet higher than the tank, could in the
summer time get pretty hot in Phoenix. If a cloud comes by the amount of
shadow could be enough to stop the pump from operating.

What kind of clouds do you get??? My ventilation fans (moving hot air
through my slab) start up at 7:45 at this time of year - when the sun isn't
even over my horizon. I'll grant that it might take a bit more incoming
light to get water (or glycol) pumping, but to be stopped by a cloud?
Seems a bit unlikely.

If you decide to use solar cells to power the pump make sure that there is
a
battery in the circuit to carry it over for the time clouds could
interrupt the production of electricity.

The ones produced locally by Thermodynamics, which have a very good track
record, have no such backup, but they do use a glycol loop and heat
exchanger, so they should be able to take a higher temperature. We also
don't get as much sun as Phoenix at the best of times.

Besides the solar pumps and cells are a lot more expensive than running a
tiny pump on the utility, IMO

Probably - installation is easier though, and there's no control circuitry
to worry about: it's on when there's current, and it's off when there
isn't.