This page is under development, this is a DRAFT article.

There are different types of Concentrated Solar Power (CSP) systems, here I will describe an inflatable one.

I am marking the references please see below with R1, R2... Rn.

I've found inflatable solar collector patents from the 60's, so the idea itself is quite old (R1.). The main advantage of such a system is the lightweight construction, that the inflatable mirror part can be much lighter, than a conventional Ag-glass mirror. Also, the cost of such a mirror can be lower. The drawback of this solution is that the reflective coefficient of the mirror is usually lower. 

I would like to build 2 small prototypes and test this system, because I think it worth the effort. 

The advantage of this system that it is scalable, so if we can build a small working sample, later we can scale it up.

The idea is that the Cassegrain Reflector (3.) is an inflatable object floating in CO2, because it is filled with air. Please see Figure 001 below. 

The inside air pressure is higher than the pressure of the CO2 (1.), so that we have a parabolic shape mirror (18.) in the bottom of the Cassegrain Reflector.

We control this inflatable Cassegrain Reflector with strings as the length of these strings are changing. The servo motors are driving the spools. So the whole system is like an inverse Marionette with a Zeppelin, in this case the floating Cassegrain Reflector. For a controlled 2 DOF movement of the Cassegrain reflector min. 3 strings are required - with 3 motors and 3 spools. From practical point of view, 4 strings could be used and only 2 motors and 4 spools. In the Figure 001 we have 3 strings, 3 motors with 3 windlasses. The motors have the necessary drive electronics and microcontroller does the position control of each motor. A separate microcontroller can do the coordinate transformation, knowing the required roll and pitch of the reflector (3.)  

The concentrated light reaches the absorber, increases the temperature of the absorber, and this heat is transferred. In a household, the heat can be utilized with a radiator (11.) or in a much bigger system this can be converted to electrical energy and used somewhere in distance. This further transfer of the heat energy and the conversion is not detailed here, in the figure 1 we can see a heat pipe (7.) transferring the heat energy from the absorber to the tank / heat exchanger (6.), this can be direct with a working fluid which could transfer the heat from the absorber directly to the radiator. (or to a turbine if there is energy conversion). The output of the system is heat energy from the absorber, and how it is utilized is just an example here. 

The advantage of this architecture is that only relatively small motors are required for the reflector movement. 

This idea was based on R1.), eventually, it turned out to be very similar to R2.) figure 34A and 34B, 40. 41., please see references.

The difference that I am suggesting to use an external balloon, which enables to use different gases than helium and hydrogen, because the gas in the external balloon (1.) is not necessary air, it can be e.g. CO2. 

The idea of using an external, protective balloon for avoiding the effects of the wind might be obvious, however this case we use it for the previously mentioned reason. 

Also, I am suggesting to use a Cassegrain Reflector (R3): a parabolic mirror and a convex mirror. This is known from the 17th century. 

Figure 001

1.) External Balloon filled with CO2 or similar gas (transparent and higher density than air).

2.) External Balloon

3.) Cassegrain Reflector Balloon

4.) Air inside the Cassegrain Reflector Ballon 

5.) Convex mirror (might be solid)

6.) Heat Exchanger / Tank (might be buried under the ground)

7.) Heat pipe

8.) Servo motor with spool

9.) Thermocouple

10.) Pump

11.) Radiator (over the ground)

12) String(s)

13.) Parabolic mirror and transparent opening on it

14.) Absorber

15.) Thermal insulation

16.) Ring

17.) Tower with heat pipe in it

18.) Cassegrain Reflector Balloon / parabolic mirror