Array direct water pumping, Lorentz vs Grundfos [RE-wrenches]

[Phil Undercuffler]

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Dave, 

The Lorentz PS pump series could easily meet those requirements.  To clear
up some confusion, the Lorentz pump isn¹t Windy¹s ³new² pump, although a new
series of controllers provide unprecedented flexibility in array
configuration.  The ETAPUMP name was involved in a trademark dispute, and
rather than fight a legal battle the manufacturer decided to change the name
to, well, his own!

The PS line comes in 3 flavors:  the PS200 for low cost systems with less
than 300 watts of pumping load, the PS600 which is similar to our previous
ETAPUMP range although now utilizing 48-72v nominal array inputs, and the
new PS1200 using 72-96v arrays.  We¹ve had very impressive results with the
new controllers that allow this increased flexibility‹they use a faster and
much improved motor commutation control than their predecessors so they are
better able to start the pump under adverse loads and conditions.

The PS AC Power Pack allows running from grid (or generator) power, at
either 110 or 220 volts (one unit, configurable with a jumper).

Unlike the Grundfos, the Lorentz dry run protection does not rely upon an
wet electrode--which as Doug notes can be fooled by certain water
conditions. This is an improvement made about 1 1/2 years ago.

Regarding eliminating the storage tank on an array-direct system, it can be
done and we¹ve heard success stories, but there are some important factors
to take into account.  First, this solution is only appropriate for sunny
climates, with a tracking array.  Otherwise, there will be long periods of
time when the pump is running at reduced flow and the system pressure will
be below that required by the emitters.  In these conditions, the zones near
the beginning of the distribution network will tend to open wide and flood,
and zones further away will be starved. Don¹t forget to add the additional
load of pressurization to your system design.  Finally, don¹t scrimp on the
size of the pressure tank, and carefully tune it to the lowest system
pressure required.  Eliminate pressure reducing fittings, which are designed
to drop city water pressure to the low pressure of a drip system.
 
Phil Undercuffler ext.238
Technical Support
phil at dankoffsolar.com

Dankoff Solar Products
    
The Premier Manufacturer and Distributor of Solar Water Pumps, and
Wholesale Distributor of Solar Electric, Wind, and Solar Heating Equipment

888-396-6611 toll free
505-473-3800 phone
505-473-3830 fax
www.dankoffsolar.com


on 4/24/05 3:58 PM, David Palumbo, Independent Power & Light at
ipl at sover.net wrote:
> I have a potential job for a PV powered water pump at a nursery business.
> Grid power is present but they like the idea of using solar to do their
> irrigation. It is a modest sized operation, the owner estimates water use of
> 1,000 to 2,000 gallons of water per day.
> 
> They had a well drilled last week. 160' deep, 9.5 gpm, static water level -
> overflowing now.
> 
> I'm looking at the new Dankoff "Lorentz" pumps, and the Grundfos SQ Flex.
> 
> An advantage to the SQ Flex would be the ability to run it on the grid power
> (when the solar is lacking) that is a short distance from the well.
> 
> Is it also worth considering eliminating the storage tank in this case? Just
> have a pressure tank setup with irrigation pipelines controlled with on/off
> valves? It will be a summertime only deal and need to be setup as a drain
> back system.
> 
> Any ideas? Experience with either the Lorentz or the Grundfos SQ Flex.
> 
> Dave Palumbo

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