DC heat? [RE-wrenches]

[Darryl Thayer]

To all
Would it be practical to operate using the battery
from 100% to 90% and then recharge.  This gives a
longer run time for the compressor of the Heat pump,
it allows the system to use one  heat pump at full
power.  

How long should a heat pump run to maintain reasonable
life expectancy?  If the heat pump could run for 1
hour on these conditions, and the off time depends
upon the charging rate?  A three ton HP at 3.3 COP
would require 3 kW for 1 hr.  This is about 60 amp hrs
at 48 volt nominal.  Or a 600 AH battery set.  

If the RE source was producing during this period the
run time would be increased.  How many cycles can a LA
battery take at 10% DOD?     

It would appear that the RE energy system would have
to be much too large for the requirements to supply a
reasonable amount of energy to this expensive energy
booster.  If it were too large then an extra means of
power dump would be required.  

just a thought. 
Darryl  

--- Randy Brooks <Randy at BrooksSolar.com> wrote:
> Geoff,
> 
> We just completed a Bergey 7.5kW turbine grid tie
> battery based system 
> using stacked GVFX3648 inverters.  Bergey
> recommended at least a 1,000 
> amp hour battery bank.  We went with a HuP Solar-One
> instead of  a 
> "s-load" of L-16s.  Much less floor space required,
> fewer 
> interconnects, less likelihood of a failed battery. 
> We installed an 
> "automatic" watering system to simplify maintenance.
>  Not cheap, but a 
> great warranty.
> 
> Randy Brooks



		
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