Solar

Background

Solar power works by converting energy from the sun to either electricity or heat.  While most people are familiar with photovoltaic (PV) panels which convert light radiated from the sun directly to electrical energy,  that same light energy may also be converted to heat for residential, commercial, and industrial uses. Usually as a supplement to fossil fuels due to the unreliability of the incident sun reaching Earth.  This section provides a brief overview of the basics of solar energy starting with the source of solar energy, our Sun.

Photovoltaics (solar cells)

Photovoltaic (PV) solar cell, which convert light directly to electricity  is the most common form of solar energy used today.

Seattle

With Germany virtue signaling green by spending more than $150 billion (USD 2018) subsidizing rooftop solar, other nations followed based on the motto, "But it works in Germany.."  Working means paying citizens whatever it took to incentivize installing solar panels on their roofs.  This works for the homeowner who makes a profit off of their neighbors paying for their solar installation through higher electric bills, the installation companies, and politicians garnering votes.  It does not work for the environment, with whole beaches in Asia being consumed to produce the silicon needed to manufacture PV panels,  or citizens in the developing world who face a tsunami of e-waste in their backyards as these panels reach the end of their 25-year life. The environment pays a steep price for the virtue-signaling policies of the wealthier who push policies to support unearned feelings of self-righteous moral superiority.

Germany's commitment to rooftop solar installations, in the worst imaginable location (cloudy skies, huge seasonal variation in power output due to northern latitude), gave others permission to follow suit, including my neighborhood in Western Washington State.  Washington State residents pay millions in taxes so a tiny number of mostly upper-income earners can make money by installing rooftop solar panels.   Panels that produce a pittance of erratic junk power because rooftop solar power production is directly proportional to the incident solar load reaching it. 

So how little power can a rooftop solar installation produce in Seattle in the winter?  Try $0.18 over 24 hours from a $10,600 rooftop installation paid for by taxes on your neighbors and more federal government money printing. Enough to run a  1.35 kW space heater for about 1 hr.  

California

How does rooftop solar work in a location like California, which has some of the sunniest areas in the US? California collects that data, which shows a 4-fold seasonal variation between the sunnier long summer days and shorter cloudier winter days.  Since the power use varies little between seasons, a billion-dollar battery backup designed to level out a daily swing in solar power is useless when it comes to dealing with a seasonal variation.  Consequently, ratepayers continue funding their existing reliable power system, typically natural gas turbines, in addition to an insanely costly and environmentally damaging battery backup.  

Similar to Germany, wind power does not provide a reliable complement to solar energy, which has a nasty habit of disappearing nightly and during cloudy weather.

Solar Energy to Heat

My desire to become a thermal analyst began in college with an interest in capturing the heat of solar energy to either generate electricity, using a Concentrating Solar-Thermal Power Plant (CSP), or provide heat for residential or industrial use.  

Concentrating Solar-Thermal Power (CSP)

CSP uses mirrors to concentrate the heat of the sun on a liquid,  raising its temperature sufficiently high to spin a turbine and generate electricity.  It requires none of the rare Earth metals of PV and offers the potential for reasonably priced short-term storage (ie; 2 to 4 hours).  Storage is critical because solar-generated electricity goes to zero at the time of maximum power needed for many locations.

Underperformance and high costs,  relative to PV, have limited CSP  growth to a small fraction of PV market penetration.  There is also the issue of a limited number of areas receiving the clear sky conditions required to produce any power, water requirements, and dead bugs and birds. 

Focused light acts like a bug zapper, with sufficient heat to fry a bird flying in the path of the reflected sunlight.

Solar Process Heat

Residential Solar

I still have my library of textbooks for designing solar space heating and hot water systems. Cost was the big issue for systems providing supplemental heat to a traditional hot water or space heating system.