way to rehab solar power fiasco, 01.12.2020

Way to rehab solar power fiasco, corrected on 23.12.2020

Author: David Judbarovski, systems engineering, principle inventor,

judbarovski@gmail.com

 

Abstract

It is wonderful way allows to restore now lost interest to solar plants.

I suppose here to show a new look and a new way to feasible solar electricity much cheaper than USD 0.01 /kWh.

 

Background

Seasonality, unpredictability, instability, low ratio of useful electricity to deployment area, illusory belief in Smart Grids really being a Big Folly in a case of large districts’ demand and supply, a cost problem to convert solar power in competitive artificial fuel because it needs electricity cheaper USD 0.01/kWh, and any other solar electricity storage is a big cost problem and so on, all those inherent all kinds solar plants as earlier stages as present one.

     

I suppose a solar power unit, consists of a planar square mirror of about 1.5 m2 served to redirect solar beams co-axially on a dish concentrator of about 1.0 m2 and being motionless, while a tiny and very simple and cheap motionless semiconductor sensor can control precisely focal spot to be motionless too with a help of two tiny servomotors. Being made of thin sheets the said mirrors are very cheap too, and totally such unit can be about USD 15.0, including steel pedestals following my very old invention and its evaluation. 

At the said motionless focal spot there is a transformer of solar energy in electricity. The said transformer comprises a thin steel sheet and three small rectennas around it with open side towards to concentrated solar beams.

Totally it is a thermal heterodyne, recently invented and evaluated by me too

We can approximate a wideband thermal radiation of blackbody at temperature T0 as a sum of narrow bands represented by radiation of their averaged frequencies each, while such isolated frequencies are interfered with everyone else, when all fall on a rectenna.

Ideally, Sin (A*t + C) + Sin (B*t) = 2 * (Sin (A + B) * t /2 + C/2)) * (Cos (A – B) * t /2 + C/2)), there

(A + B) / 2 and (A – B) /2 are two abovementioned separated bands of frequencies.

Mix of blue band with yellow one forms to band, one is green band and another is about from 1.5 nu to 2.5 nu..

In our case of thermal radiation, we can consider it fallen on rectenna array with resonators restricted by limits from 0.0 THz to 10.0 THz being our (A – B) /2,  here A and B are two limits of thermal radiation band near the peak wave length for a designed temperature T0.

For example, if T0 = 700 C, the peak wave length L0 = 3.0 um, corresponding to peak frequency 57.21 THz, we can choice the band interval of A = 47.21 THz to B = 67.21 THz (Lmin = 2.535um, and Lmax = 3.608 um), so (A – B)/2 = 10 THz chosen to be our rectenna frequency.  

Using Plank’s Law on-line calculator for blackbody, the Radiant emmitance is W = 50.8 kW/m2 and Band Radiance is B = 47.0 kW/m2 for our solar thermal concentrator's design.

So our rectenna is k = 50.8 times smaller cross-section than origin solar flux, so correspondingly cheaper and simpler in production. Its energy efficiency is n = 3/4 * B/W= 3/4 * 47 / 50.8  = 70.0 % vs. 18% for commercial PV solar cells.

Analogous calculations gives for T0 = 900 C, k = 109 and n = 57 %

The cost of such electricity can be calculated by a formula: 

Q US cents/kWh =  ( 15 / (0.8 * n) + q * 1000 * 4 / k ) ) / ( H *  t ), 

here: 15 $/ m2, 0.8 - rectenna energy efficiency,  n -thermal efficiency, q - cost of rectenna USD /W, k - solar concentration, H - direct sun hours in a year, t - years of payback

At T0 = 700 C, k = 50.8,  n = 0.7; q is supposed to be USD 2.0 / W, H = 2400 hours / year, at t = 5 year, so Q - USD  0.015/ kWh = 1.5 cent/kWh 

For T0 = 900 C, it is Q = 0.9 cent/kWh !!!, and to be practically free after 5 year payback period.

It can be practically free also during the payback, if using breeding investment for building with breeding rate 2.0 during 5 years payback (see Breeding for cheap energy cheapening, posted on 3.11.2020 in https://judbarovski.blogspot.com/2020/11 )

Moreover, we can make the solar energy supply by very cheap way round the clock and all year round and to guarantee a long autonomous powering in emergencies, e.g. if a war or other catastrophic cases. It was disclosed conceptually in article “Fundamental breakthrough energetics” being posted on 7.11.2020 in https://judbarovski.blogspot.com/2020/11 .