Solar Harvester

Introduction

We are an infant Antonyan's type three civilization according to the blog post about Kardashev scale of civilizations. We certainly have advanced computational power, but we are lucking energy source to realize our potential. In above post we determined that the Dyson sphere is for wimps, so lets define the machine that jump starts our civilization with huge energy inflow. The new design that can take us to the next level of energy freedom is building a machine that is cheap, easily produced and can happily thrive during decades of operation and generate unlimited amount of energy in its lifetime. Notice that we don't need to invent an energy source, we already have unlimited amount of energy at our disposal located in the closest star to our planet, the Sun. Thermonuclear reactions inside the Sun will last another four billion years, so our attempts to recreate same reaction on Earth is childish and irresponsible at best. Instead of spending hundreds of billions dollars trying to light the thermonuclear fire on Earth, why don't we spend tens of billions utilizing the natural reactor that is available to us. Besides it is pointless even to dream that we'll ever generate as much energy as the Sun on Earth. To utilize the Sun's energy we need to start harvesting it at at large scale. Note that harvesting refers to the collection of emitted matter as well as energy from the Sun. And then we need to be able to transmit/transport the collected material and energy to large distances with high accuracy. This functionality is handled by Solar Harvester machine.

Basic Functionality of Solar Harvester and its Design

Solar harvester is a machine that is parked close to the sun and uses Solar energy and Solar wind to generate powerful laser beam and stream of materials. Some of the energy is used on the harvester to concentrate and otherwise process the materials before sending them into matter stream. Some portion of energy is used for self preservation of Solar Harvester. Remainder of energy is transmitted to predetermined coordinates that define location of energy re-transmission stations.

Five Rules for successful design and deployment of Solar Harvesters

In order to evaluate feasibility of solar harvester lets define some rules and parameters for initial design.

1. Do not overheat external shell! The construction and materials of Solar Harvester should withstand environmental conditions present near the Sun, this include radiation as well. To protect from overheating we have only one option to use forced cooling using Suns Energy.
2. Prioritize self preservation! This is number one goal of Solar Harvester, since we want machine that survives for decades without down time
3. Locate Solar Harvester as close to the Sun as possible without violating rule 1 and 2. This is paramount design constraint and as the technology improves we will go closer to the Sun.
4. Select technology for energy generation that satisfies rules 1, 2, 3. Note that energy generation efficiency is not important, as long as we produce more then utilize
5. Select technology for matter transfer that satisfies/supports 1, 2, 3, 4. 

Rule 1: Do not overheat!

This rule is simplest of all and easily calculated. One simplistic Solar Harvester model is Heat collector and attached to Heat sink and some kind of machinery that harvests energy presented by energy difference. This sounds some kind complex machinery but it is nothing new. Consider using Nuclear power station guts and throwing away the reactor. Note that in the vacuum of space rules of thermodynamics work just fine and all we need to do is find efficient heat sink. Such electricity generation facility will have about 60% efficiency, so we need to dump 40% of excess heat. The heat dissipation is done using Heat Sink to emit infrared radiation. So for this we can use some kind of refrigeration unit and we have multiple options but lets use Heat Pump. So for the shell we can use steel and cool it down with heat collector and cooling the excess heat with heat pump. We can use large Heat sink area to Heat collector area to make the cooling problem even easier to handle. Imagine long cylindrical Solar Harvester that faces the Sun with its top and uses rest of its surface area as heat sink. So basically we have all the technology and materials to efficiently handle this rule.

Rule 2: Prioritize self preservation! 

This rule has paramount importance. Basically to be useful the Solar Harvester should be designed to survive harshest environments and have long operational life. The design should use redundancy of all critical systems and should have adequate shield to insure relaxed operating conditions of internal machinery and most importantly the controls, brains of the system.  The only hot part should be the Heat shield/collector and rest of the structure should be cooled. Solar harvester should have enough energy, fuel and coolant storage to insure adequate time to recover from any catastrophic failure. Designs like this are available and can be adapted to the technology, so no need to reinvent the wheel.

Rule 3: Locate Solar Harvester as close to the Sun as possible

The best position for Solar Harvester is at close proximity to the sun or in other words almost touching it. This location is the best considering highest energy levels available and access to immediate vacuum of space for cooling. If Sun had hard surface we would have been landing on it. But since the Suns surface is gaseous and very turbulent, we will be at some distance from it, somewhere in photosphere. Good analogy to solar harvester propulsion would be the dirigible, equipped with emergency rocket engines. We will need constant access to cold space to dissipate/conduct heat to survive and produce energy. At first glance it seems impossible to survive at close proximity to the Sun but once we get over the initial shock of the idea we can see that it is just matter of energy transfer and cooling. For example we can say that anyone can hold piece of Sun or molten steel in their hand without damage, as long as it does not have enough energy to burn your skin. So the temperature of sun surface does not matter but actual energy density. And we don't need any exotic materials to survive the close proximity of the Sun. And we can start by incrementally going closer to the Sun until we are close to violating Rule 1 or 2.

Rule 4: Select technology for energy generation that satisfies rules 1, 2, 3

On Earth we have no shortage of energy generation methods. But for useful Solar Harvester we need to use turbine generators, or basically all the standard machinery that is used for nuclear power generation. Imagine system with four 250 Megawatt generators and support machinery. Note that we need to come up with methods of energy utilization/transmission. The energy is utilized to create matter stream, build containers and energize lasers and power RF transmission. Megawatt rated Lasers and RF transmitters are readily available so no exotic technology or materials need to be invented.

Rule 5: Select technology for matter stream that satisfies rules 1, 2, 3, 4

The matter stream is actually number of transport spaceships that get their initial speed boost by energy transmitted by Solar Harvester. Basically those are interplanetary spaceships that luck first stage engines. These ships are automatic and do not have any support personnel, since they are subjected to thousands of G's acceleration during launch and harsh radiation. The ships would be built on board of Solar Harvester and require constant delivery of raw material. But this should not pose a problem. We are type 3 civilization and have enough material to realize our destiny.

Example Solar Harvester design

The design will utilize triple redundancy as its basis of operation. The generated electricity will be used to power the heat pump, generate powerful Laser beam, generate powerful RF beam (microwave beam power transfer) and to keep sun stationery orbit or its distance in photosphere.

Heat shield

The Heat shield of solar harvester is assembly of heat pipe array that provides shadow. The principle of operation is very simple. At surface of the sun the energy density is about 6KWt/cm2. The best heat pipes we have can conduct over 22KWt/cm2. So if we can dissipate the energy of the heat pipe then we can even land on Sun if such feat is possible. Heat shield is copper conductor 1” squares coupled to 0.25” diameter heat pipe’s (three), routed to three different turbines.  There is a small gap of 0.1” between copper squares to allow light passage and material collection. The heat shield can be cylindrical shape at immediate vicinity of the Sun. As the Solar Harvester technology improves, we can get closer to the Sun. Solar harvester operation can be easily emulated on earth by placing it in the focal point of solar concentrator in vacuum. Once we come up with closed loop machine that can survive this conditions and generate energy for long period, we can start deploying solar harvesters.

Material sink

The sink concentrates material emitted by solar winds that passes through tiny gaps of the heat shield and feeds it to compressor.

Compressor

The compressor is electrically operated multistage turbine coupled to electric motor on magnetic bearings. At extreme distances from the Sun we can use activated Carbon to store the gases that would be released by electric heaters. The gases/materials would be used to power rocket engines.

Rocket engines

Rocket engines are used to keep the Solar Harvester in  Sun stationary orbit or its photosphere. The engines are electrically powered ion engines at long distance from the Sun or could be turbofan powered by friction-less induction motor.

Closed loop Turbine

The simplest design of solar harvester energy generator will be closed loop Turbine design behind the heat shield/source. The turbine will be running in thermally relaxed mode and at minimal part stress levels to provide longest possible operational duration. It will have no moving parts that are in contact since all of its components will have magnetic bearings.

The generator will have permanent magnets that can be optionally magnetized by magnetically coupled coils. The cooling of turbine will be done using Heat pumps.

Heat pump

The heat pump has no contacting moving parts and designed to cool the turbine and dump the rejected heat on the radiator. One design will have turbine coupled with inductive electrical engine on magnetic bearings. Another option for heat pump would be paltier coolers powered by electricity.

Solar Harvester Energy utilization to jump start the Type 3 civilization

Portion of energy of Solar Harvester is  transmitted via powerful beam of laser to arbitrary location in solar system. There would be Laser re-transmission stations in the solar system to refocus the laser, located at sane distance from Solar Harvester. Energy beam and material stream can be targeted precisely at arbitrary location in our solar system. Formation of thousands/millions of those Harvesters will provide trillions of megawatts power and energy amount available to our civilization will increase by several orders of magnitude. This energy can be concentrated to increase power output of ISS solar panels, provide power to light sail powered spacecraft, help asteroid mining/elimination and help terraform Mars in a decade. Initially almost all the energy produced by Solar harvesters would be used to create more of them. Then after we reach some comfortable number of harvesters , our civilization can start utilizing our newly found muscles that matches our intelligence size. The technology required to build Solar Harvester is available today and the design can be done to insure decades of operation with no additional support. We can use it to permanently shield Earth from Solar wind or power interstellar ships. Those ships will carry solar harvesters to other stars and in short time we will have colonies in our immediate Star system proximity and spread throughout the galaxy.