Laing D5 Ecocirc pump

[westbranch]

Does anyone here have experience with this pump?

http://www.lainginc.com/pdf/LTID5solar.pdf

It has a built in MPPT capability...

Eric

[niel]

interesting. although i'm not a pump expert, i see some things that make me wonder.
1> with a 12v to 24v range this leaves out both nominal 12v and 24v battery setups as 12v batteries can fall below 12v and 24v batteries can go above 24v.
2> with a 230 degrees temperature on some models says that this is capable of running with steam being above the boiling point meaning it can pump a gas.

[icarus]

As for your first point, it sounds like it will run on any voltage from ~12-24 nom. Many other pumps including the shurflo 9300 series will run just fine as low as ~10 vdc, but will pump twice as much water at 24 vdc.

Water under pressure can be considerably above 212f without boiling, so it sounds like you could use it for a hot water heating system that runs at temps up to 230f (~20psi)
http://www.engineeringtoolbox.com/bo...ter-d_926.html

Tony

[mike95490]

Only has a 12' max head. That's not going to pump from the basement to the rooftop solar collector.

i think these are made to be in a batteryless system, just a PV panel.

[icarus]

Mike,

I saw that it only has 12' of head, but when I looked at the spec and saw a much higher psi (~250?) I thought that the 12' might be what the pump would "suck" from, not what it would push to. Someone will have to look into it a bit more.

Tony

[niel]

i have to go by it says and it does not say nominally. they specified the range in black and white and if it was capable of more then they should've put it in there to reflect the true range. not a good marketing practice on their part. there's just a gut feeling that i don't trust it. i hope i'm wrong.

[westbranch]

Mike got it right ... from the first page:

The first DC spherical motor pump for direct
connection to photovoltaic panels with automatic
performance optimization using
Maximum Power Point (MPP) tracking

that is the point I noticed first, direct connection, NO CC needed.

second the low lift... BUT in a closed loop system the fluid is already at height X and the pump really only has to improve on the heat syphon effect "pumping"or pushing from the lowest point, it is kind of like the static level of a well... lift is only from that elevation not the bottom of the well... at least that is my story...

As to Tonys point on volume moved, it is about the size of an orange, fitting in the palm of a hand. pretty compact. the D5 720 is only 2.5 inches across the top

Note the low Amperage drawn!

I will see if they can answer the lift question directly

here is a more readable PDF for the specs

http://www.oberread.com/Download%20Files/D5_Solar.pdf

HTH

Eric

[stephendv]

Conceptually a direct powered DC pump is such a nice idea - the more sun there is, the hotter the water is, the more power the PV generates so the faster the pump turns.

I wonder if you sized the PV just right where you could even run the system without a temperature difference controller?

[peakbagger]

I have a dc pump direct connected to DC PV panel for my SHW system. I started out without a temperature controller, but soon switched to an Artech DC controller as I found that on cold days, the pump would run long before the panel warmed up in the AM, therefore dropping the temp in my storage rather than raising it. I have a Laing pump sitting in a box to replace my current March pump when it dies or I have the system drained.

As discussed the pump is circulation pump. Pumps are usually rated for feet of head as hyrdraulic folks use feet of head instead of PSI. Divide by 2.31 for 60 F water to get PSI. The pumps use is to overcome the friction in the piping and equipment, not to lift a fluid from one elevation to another. If one insists and they have a flooded suction, the circ pump can pump up the distance in feet on the pump curve assuming the piping is real big so there is no significant contribution from pipe friction. The pumps needs flow to keep cool, so the worse thing to do is try to pump higher than the pump curve, as the pump will be unable to flow any liquid and will instead heat up.

The 150 PSI rating is the maximum pressure the casting will survive before leaking. Generally a SHW system is pressurized with a seperate pump usually called a charge pump, that is only needed when the system is set up and subsequently if there are leaks or someone deliberately drains the system down. The charge pump is rarely included with the system, so the typical homeowner would have to buy one or have a pro do a refill. I am not aware of any dual purpose pump that would work well as both a charge and circulation pump as the operating requirements are quite different.

A frequent problem with "orphan" systems is the new owner trying to run at low pressures which can lead to fluid boiling in the collectors, which leads to glycol breakdown (going acidic) and pressure relief valves popping off.

[westbranch]

Peakbagger, what about the non pressurized systems? Are they less efficient at collection? seems they would have a lot less issues with over pressure as the excess would go into an overflow tank or ?...

Also sounds like larger piping is desirable to lower friction losses.

Eric