Green Collar Careers - Future
Solar Heat Products
One of the "hot new technologies" that's been emerging from a 200
year slumber are Stirling Engines. These engines are
among the few that can be powered directly from solar energy.
Some large scale systems are currently generating electricity in the
Mojave desert with that electricity powering homes in San Diego.
Smaller scale systems are in trials today with excellent results.
The Infinia design
clearly stands out among the rest as there are virtually no friction
parts in the engine. Incredible as that may seem the design uses
close tolerance components and rather then bearings to guide the
piston in the cylinder it employs an ingenious device to maintain
precise alignment. As a result no oil is required nor does it
require any service for an estimated 25 years. This design was
first tested over 20 years ago.
The cost of these systems are
currently estimated to be in the $6 per watt range and given dedicated
mass production projected costs are in the $3 a watt range or less.
The current systems are directly heated by the sun using a tracking
parabolic mirror. The focused heat of the sun produces
temperatures in excess of 1000° to heat the working gas Helium, and
the system is totally sealed with the generator inside the Helium
The video above shows a cross section of how this
Stirling Engine Generator works. Like all solar powered devices
the current configuration only produces electricity when the sun is
shining. However by storing the thermal energy in a heated mass
a Stirling Engine generator could run 24 hours a day. The cost
of a thermal storage mass is much less then batteries giving some
significant advantages to this system. Watch the
The Infinia system is tooling up for mass production with
deliveries planned by the beginning of 2010. No doubt these
systems will spawn the development of parabolics used to heat water.
Europe has been promoting the development of Micro Combined Heat and
Power (m-CHP) appliances that currently operate on combustible fuels
from natural gas to wood. Using a Stirling Engine Generators
they produce electricity very efficiently with claims of lower costs
then commercial AC at retail prices.
Tracking Parabolic collectors are on the rise, particularly with
ground mounted systems. As the cost of drive systems has
plummeted with a significant improvement to reliability, parabolic
systems are beginning to rival flat panel cost with major improvements
in thermal production at times of low solar energy availability - such
as cloudy days and when the sun is lower towards the horizon.
In colder climates Solar heating has been slowly catching on and
requires quite a bit more energy then water heating. Tracking
Parabolics systems have been gaining some excellent results in the
Nordic region and should be commercially available in the United
States by 2015.
China has long been an advocate of using the solar water heating and
some systems from China are now SRCC qualified with more coming.
India has more recently taken an interest in solar water heating
and no doubt will also become a low cost source in the coming years.