Intro, Mod vs. Sine, Trace UT-SW MPPT & THD, ConServ/Vestfrost reliability, NE

[Pat Kiernan]

<x-flowed>Hello wrenches!

First an intro ...

Name: Pat Kiernan

Company: Eco Electric, Inc. PO Box 2389, Basalt, CO 81621

Company Description: Licensed electrical contractor specializing in 
renewable energy and energy efficiency.

I have been installing PV since 1989. The company was started in 
1993, with the intention of doing a variety of electrical work 
initially and focusing on RE as the market allowed. Initially about 
20% was RE, last year 60 to 70%. Our work is primarily PV, last year 
more grid-tied than stand alone. We work occasionally with wind or 
hydro. Being 20 miles from Aspen, I have the option of supplementing 
the RE opportunities with residential and commercial wiring as 
needed. In stand alone residential situations, we often do the RE as 
well as the electrical design and wiring for the home. This allows us 
to provide an integrated combination of energy production and 
efficient electrical equipment.

The largest PV system I have installed is 4.5 kW. The most satisfying 
is a 450 watt system with a backup Korean war surplus generator that 
is largely silent all summer. To see a couple and young child live 
simply and well with this system has been an inspiration in treading 
lightly!

I have not sold a mod sine in several years. Even in modest systems I 
encourage owners to bite the sine bullet up front, rather than deal 
with ongoing equipment irritations. Off grid sine units we install 
are primarily Trace SW. Grid tied are a mix of Trace UT-SW and AES 
GC-1000.

The biggest problems we've had with Trace SW units are 
erratic performance of clocks, non-user friendly controls and 
manuals, and sketchy technical support.

The Trace UT-SW (grid tie, no battery) have exhibited a couple of 
problems. The MPPT voltage with three series single crystal PV 
modules should track at about 48 to 51 volts. Some units consistently 
track at about 39 volts, resulting in about 20% less power. Trace has 
updated firmware that I will be installing in a couple units in the 
next few weeks that is intended to correct this. Also, one report 
claims that Trace UT-SW units operating at 25% (1kW on a 4kW SW) of 
rated power have a THD of 17%.

The AES GC-1000 is fairly new -- our first ones went in last year. 
They are a very easy package to wire when purchased with the 
combiner/GFCI/AC&DC disconnect package. I don't have a power quality 
meter, so have not measured the purity of output. Some of the wiring 
terminal blocks and fuse holders are a bit flimsy and need to be 
handled with care.

Anyone out there able to speak to the surge capacity/overload 
protection of switching technology sines like the ProSine? I'd like 
to give them a try.

Any pros/cons/reliability info out there on  the ConServ/Vestfrost 
refrigerators and freezers?

There are quite a number of proposals to amend the PV section of the 
2002 NEC. I encourage you all to review and comment so the wrenches 
can balance out the paper electricians.

Fellow wrenches, I am delighted to be included in your company. I'm 
enjoying the philosophical and technical discussions.

Pat Kiernan

Eco Electric, Inc.




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