re: small solar grid intertie inverters?
17 may 2004
solar guppy wrote:
>well nick , you are not one to shy from opinions ... it would be nice if
>even once , you would back these up with something you actually built.
i've designed and built many things in 40 years of electrical engineering :-)
>...my view is based on what three major manufactures have found out ..
>even the sub 1000 watt inverters have a very small market...
i have a different view.
>if you think there is a "tremendous" market for a 100 watt , ul1741
>certified inverter , why don't you design , test , certify and market it ?
i'm more interested in heat energy...
many people have heard of ohm's law in connection with photovoltaics, but
they may not be aware that it also applies to heatflow in houses (with
different units) and that solar heating can be enormously cheaper per peak
watt than solar electricity and that most houses need more heat than electrical
energy (the ratio is 1:1 in hawaii and 5:1 in vermont) and that this small
slice of the home energy pie can shrink even further with more efficient
appliances and compact fluorescent bulbs...
our july 9 workshop on "ohm's law for heatflow" with applications to solar
water and house heating and natural cooling is partly a basic tutorial
("what is a btu?"), and partly a discussion of tried and untried schemes
for increasing solar heating fractions ("how much does performance improve
over direct gain if we remove the mass and separate the sunspace from the
living space with an insulated wall and circulate warm air between the
sunspace and the living space during the day and stop the air circulation
and let the sunspace get cold at night?" is a question that can't be
answered with energy-10...)
we'll provide arithmetic and data and strategies needed to site-build
effective house heating and cooling systems using common, inexpensive skills
and materials like curved 1x3s and polycarbonate glazing. participants
should be familiar with high school algebra. we'll use calculators to design
houses to be 100% solar-heated in the worst-case month of the year, using
monthly averages from nrel's solar radiation data manual for buildings ("blue
book.") we would do simple, direct, laptop simulations for various solar
house heating configurations with tmy2 weather data and basic or spreadsheet
programs, using simple equations from physics for deep insight.
we'll discuss power, energy, heatflow, and overnight and cloudy day heat
storage at the high-school math and physics level, with insulation values
and heat capacities of materials, time constants, evaporative and nocturnal
ventilation cooling with "smart whole house fan controllers," passive and
low-energy solar heating, superinsulated houses, and ideas for houses that
are 100% solar-heated, by design. promising techniques include solar closets
and shelfboxes, soap bubble foam insulation, and 2:1 concentrating solar
attics that collect heat and electricity from standard pv panels under
drain-down water-filled lay-flat poly film ducts on the attic floor.
we'll also discuss a simple counterflow greywater heat exchanger, a $60
1"x300' plastic pipe coiled inside a 55-gallon drum. with hot water bursts
of 13 gallons or less, this could be 97% efficient, and maybe illegal, these
days, like harry thomason's single-wall galvanized tank heat exchangers.
handouts will include a workshop writeup on paper and a cd-rom containing
most of harry thomason's patents and writings and the data from nrel's blue
book and the paper "solar closets and sunspaces" by nick pine and paul bashus
and the book sunspots by steve baer and bill shurcliff's new inventions in
low-cost solar heating book and some pamphlets written by baer and shurcliff
and some design guidelines from pe norman saunders and the solar today stories
"solar heat in snow country" and "soldiers grove soldiers on" by nick pine
and drew gillett and some photos of soldiers grove and michael schofield's
1991 thesis "an economic evaluation of solar energy at soldiers grove."
i'm an ee by training and a registered us patent agent. i gave a similar
workshop on 10/4/03 for 20 people at the sustainable resources/engineers
without borders conference in boulder, co. steve baer is a world-famous
solar guru. rich komp is president of the maine solar energy association
and a pv author with a pchem phd and lots of solar house heating experience,
and drew gillett is an me/ce/pe with architectural training.
join solar guru steve baer and pe drew gillett and phd rich komp and
me for an all-day workshop on solar house heating and natural cooling
strategies ("hvac nonsense") on july 9 in portland, or--see page 25 of