9.0 Notes (page 7)

< Seed Factories

back to page 6

F.2.1.1.1.1 Control Location Data

This function provides control of all operational tasks at the location, including those Habitation and Transport tasks not controlled internally to their respective elements. An example of this would be deferring Habitation clothes washing to manage peak location power requirements. Internal control of elements is provided as needed. For example, a local controller may monitor the temperature of a kiln, and communicate with the outside to get new tasking and report status. The control function includes human future planning and retrospective analysis, generating real time commands to elements, displays, observation of conditions, and operations data collection. It also includes tasks like accepting outside sales orders, acquiring outside supplies, and internal bookkeeping and output allocation. It is implemented by a mix of local and remote controls, and a mix of human, automated, and software commands and actions.

Control Location Requirements

Control Location Alternatives

- Outside the program, which includes the natural environment and human civilization,
- Other program phases, which will be only Phase 0 at the start of building this location,
- Other environment ranges than Temperate, which there likely will be none at first, and
- Other locations in the Temperate range, which we also expect none at first, since this is the first location, but can add new ones later.
This task conventionally is performed as part of Manufacturing Resource Planning (MRP II), a factory planning method. We are unlikely to invent a new method for this task, so it seems more feasible to adapt existing methods to our situation, where part of the factory output goes to building more factory. MRP II can be used for other parts of the control function. We will use it where it applies, and we may build custom spreadsheets, databases, websites, and software where needed. The task will require human labor to interact with outside entities, and at a minimum oversee the control task. At first it is expected to require more manual data inputs and calculations, but the goal over time is to automate this task along with the other control jobs.
To the extent they are automated, the production elements will have their own local control software to do the discrete operations, and will report back status to the control system. The system elements to perform this task will include humans, control software, which is likely to be custom, and computers and a network to deliver the orders and track progress.


F.2.1.1.1.2 Supply Power Data

This function provides electrical, thermal, hydraulic, and other forms of energy for all parts of the location, plus a large surplus. The high output ratio comes from the program level goal of expanding the material and energy resources of civilization as a whole. It also supports a high quality of life for project members by having ample available energy for their needs, and income from sales of the surplus. Finally, we want to make a positive contribution to environment impact by relying on renewable sources where possible.

Power supply can be divided by type (electrical, thermal, etc.) and parameters within a type: voltage and current for electrical; temperature, duration, and accuracy for thermal; pressure and flow rate for hydraulic. It can also be divided into service classes by reliability: residential and control functions should be more reliable than industrial tasks that can be deferred. Finally it can be divided into fixed and portable.

Supply Power Requirements

Supply Power Alternatives

This alternative uses a large mirror area to focus sunlight onto a small target to reach high process temperatures or generate large amounts of electricity. We will define concentration ratios of more than 4:1 as high. Some means accommodating the Sun's daily motion is needed. We will use Atlanta, GA as a "typical" location for calculation purposes, but other locations need to adjust for their actual circumstances:

Solar Resource - Hours/day of total sunlight for Atlanta GA: 4.09 winter, 5.16 summer, 4.74 average. For direct sunlight, average = 4.2 hours (suitable for thermal concentrator). Assume similar range for direct as for total hours by season, thus 3.55 to 4.62. Terrain and nearby objects can affect this.
Unit Spacing - For year-round operation, you do not want winter shadows from one unit to affect the next too much. For a latitude of 34 degrees North for Atlanta we assume a tilt of 34+15=49 degrees for the mirrors, and therefore a unit spacing of 1.15 times the difference between highest and lowest points of a unit mirror array to avoid shadowing, in addition to their ground footprint at that tilt angle. If the array dimension is D, the ground footprint will be cos(49 degrees) x D = 0.65D. The height difference will be sin(49 degrees) x D = 0.75D, and thus the extra spacing will be 0.87D. The total unit spacing for a north-south line of units is then 1.52 D. For east-west spacing, solar intensity due to atmosphere absorption falls 20% at 65 degree zenith angle (25 degrees above the horizon) and 50% at 80 degrees zenith angle. The unit spacing will then depend on whether you want to maximize output per unit, or output per ground area, and how many continuous hours of sun you need for a given process. For calculation purposes, we will assume a 65 degree zenith angle as an operating limit. Then the array spacing needs to be 1.94H + 0.43W, where H is the maximum array height (0.75D in our case) and W is the array width east-west. Combining spacings, we find that mirror area is about 35% of ground area. The remainder can be filled with short plants which do not require a lot of direct sun or secondary industrial tasks which benefit from small amounts of sunlight.
Economics - Peak sunlight has a standard value of 1000W/m2. Therefore average solar input is expected to be 1000 W x (4.2/24 hours per day) x (35% ground fill area) = 61 W/m2 of ground area. Net useful power depends on efficiency losses in the mirrors and later steps in using the energy. Over the course of a year, 61 W average power yields 1925 MJ. At an energy cost from conventional sources of $0.03/MJ, the land area then yields up to $57.75/m2/year ($233,700/acre/year).
Sandia National Laboratory estimated the cost of a tracking heliostat at $125/m2 in 2006. Adjusting for inflation and ground coverage, we obtain a cost of $50.5/m2 of ground area. This implies the concentrator assembly would theoretically pay for itself in 0.875 years, or a return rate of 114%. This does not count whatever equipment is at the focus to use the collected energy. This is a promising rate of return. If self-production can lower the cost of the equipment, this is potentially very promising.
Alternatives
- Central system - This uses a set of individually steered heliostats (mirrors) aimed at a central target. Depending on size and distance the heliostats can be flat, curved, or segmented. At least 10 curved heliostats are likely needed for 400:1 concentration, or the ability to adjust the shape to compensate for off-axis pointing as the Sun moves. Alternately a group of flat heliostats move on a circular track to track sun azimuth, and tilt for elevation, with a curved secondary to reach a fixed target at ground level. The secondary is elevated for average latitude tilt. This keeps most of the mirrors at ground level, and they can share a common tilt mechanism. Terrain will affect the design of any solar concentrators system.
- Dish System - This uses a single steerable dish with either an elevated target or a secondary mirror to direct the light to a fixed or ground level target. Using a single dish limits the size because of the support structure required, and an elevated target is more difficult to use. However, a fixed shape dish can more easily reach higher concentration ratios.
- Linear System - This uses a parabolic trough or linear Fresnel mirror arrangement oriented East-West to reach moderately high concentrations. A long device minimizes end losses from the Sun's motion, and only requires minor seasonal adjustment daily.
- Polar System - This is a flattened layout of mirrors on a polar axis mount, with the focus or secondary towards the lower end. It is effectively a segment of a circular dish, but the flat layout and keeping only the upper end of the dish lowers the focus and support structure. The polar axis tracks daily Sun motion, and a seasonal tilt adjustment accounts for the Sun's declination in the sky.


This uses fixed or seasonal reflectors with mirror/target area ratios of 0.0 to 4.0. A zero mirror area means the target is directly exposed to the sun with no extra help. Some examples are greenhouses or lumber drying sheds with moderate reflector areas to increase winter growth or speed drying. Building air and water heating and direct solar cooking can be done at these ratios.


Direct sunlight in an average location is only available about 4 hours/day, and in the best locations for 8 hours/day. Thermal storage allows extending high temperature processes or power generation for more hours per day, at the expense of more collector area and a storage system. Various thermal storage media have been tried, including high temperature oils, molten salt, either of those with solid fillers, and dry rock. Heat transfer media can include the oil or salt directly, piped water/steam, unpressurized humid air, or dry air. Heat exchangers are required if the transfer medium is not the same as the point of use medium.

- From Specific Heat Data, ordinary rock has a specific heat of 800 Joules/kg-K, and a cubic meter of crushed rock has a mass of about 1400 kg. If you heat the rock by 500 K, then one cubic meter can store 560 MJ, or 155 KWh or about $19 worth of electricity at typical utility rates. It is equal to 90 Prius battery packs.
- Insulation is required so the stored heat does not leak to the surroundings too quickly. Rock wool has a conductivity of 0.045 W/(m-K), and a use temperature up to 1000 C. Insulating Firebrick has various properties depending on composition and temperature rating. If we use the lowest grade (1260 C rating), it has a hot load capacity of 69 kPa, which allows 5 meters maximum gravel load, and 3 meters design load. Conductivity vs temperature C is [260,0.13], [538, 0.17], [816, 0.22], [1093, 0.24] W/(m-K). Concrete and stone have conductivity of 1.7 W/(m-K), and concrete has a maximum working temperature of ~400C under load (this varies by mix type).
An assembly of gravel at 1000C hot storage temperature, 0.25 meters of firebrick, and 0.15 meters of concrete would lose 450W/m2. For a 1 meter cube, the storage time constant is 200,000 seconds. Refractory concrete is a special mix which can withstand higher temperatures.
- An option is vacuum/powder insulated storage. The vacuum reduces heat transmission, and the powder fill supports the storage vessel against the pressure difference. This is likely to be more expensive than concrete storage units, but may be useful for portable applications.


This is primarily photovoltaic (PV), or solar panels, which have reached mass production levels. Sun-facing fixed panels are the least expensive to set up, but tracker units are an option. Concentrator PV can reach higher area efficiency for the panel, but requires spacing of the tracker units to not shade each other. Using only purchased concentrator cells and self-building the rest of the system would increase percentage of local production. This would combine with the high concentration designs above. Some lower efficiency technologies should be considered if they offer low cost and are producible: dye or oxide cells, integrated roofing/PV, window integrated cells.

- Polar Axis Mount - The purpose of this option is to get increased output from purchased panels relative to stationary mounts. The polar axis mounting allows following the Sun. An average tilt is used, since seasonal declination is a small loss. Depending on thermal limit of the panel, side reflectors or placing the panels at a reflector focus will increase output. Active cooling may keep the panels from overheating. Compare to using concentrator cells designed for high flux.


One concept is a tower with volute turbine units on a circular track mount. Track is L shaped, with upright and sideways rollers for support and position, and a cover to keep debris off. Turbine units are paired, set behind center of rotation, with dihedral, so they auto-point into the wind. Larger units may use a drive motor for pointing. Units are stacked vertically on the tower to get more total output. Tower height is used to get above trees and into higher wind velocity.


This is using plant wastes, microorganisms, external trash, or other organic sources either to create a liquid fuel for transport, or direct combustion of solid, liquid, or gas products for heating or power. This may be in parallel with wood or food production from plants. An option is to use CO2 byproducts from combustion or other production processes to increase growth rates. Bioenergy is limited to about 6% solar efficiency in the best case, and much lower for unmodified plants, so on the whole is much lower efficiency than solar options, even when storage losses are included. Reasons to use it include portable power, and off-hours when other energy sources are not functioning. Organic sources are likely to be more useful as chemical feedstocks than as fuel, so the value in alternate uses should be considered.


We do not assume the location has special features like hydroelectric or geothermal potential, but if such an option is available when selecting land it should be considered as a plus. Fossil energy sources are unlikely to be found, but we would prefer to use them, if available, for non-energy uses so as to not add to atmospheric CO2. Other storage options like compressed gas, large batteries, and deep well gravity can be investigated to see if any done as self-built would be economical.

F.2.1.1.1.3 Extract Materials Data

Extracting raw materials covers steps before a material is in inventory and ready for further processing or use. It includes tasks like mining, water, and air collection from the environment, and harvesting organic products from living things. After extraction it usually requires transport to another production function. It includes doing this on owned or leased location land, or from other property using internal equipment to do the extraction and transport. Materials mined and delivered by others using their equipment is an external supply, accounted for elsewhere.

Extract Materials Requirements

Extract Materials Alternatives

- Generalized resources: These are ones generally available in most locations and not particularly specialized, such as local rock, soil, plants, air, and water flow.
- Specialized resources: These include nearby mineral deposits, outside recycling, scrap, trash, and waste sources, and commercial raw materials suppliers.
- Habitation foundations: 27 m3/person x 75 people/year = 2,025 m3/year of suitable gravel and sand aggregates, of which 15% needs to be limestone and shale for cement making.
- Habitation Roofing: 3 m3/person x 75 people/year = 225 m3/year of clay or cement ingredients for roof tile.
- Habitation Siding: 24 m3/person x 75 people/year = 1,800 m3/year of suitable clay and sand for brick making.
- Total Water Use - Data from Water Footprints (Mekonnen - 2011) indicates USA total water use for all purposes was 2840 m3/year/person. This does not include any recycling, and includes water used in agriculture, so should be considered an upper bound on water collection.
- Domestic Water Use - Data from several sources indicate US residential use averages 0.6 m3/day/person (220/year). Again, this should be considered an upper bound with no re-use.
- Framing Lumber: During construction we need (40 m3/person for living space + 10 m3/person for roof support) x 75 people/year = 3,750 m3/year of finished lumber. Assuming 75% conversion of raw logs to finished lumber, that means harvesting 5,000 m3/year of logs.
- Food Plants: (Needs data)
- Other Plants: Includes harvesting fruits from trees, non-food plants used for fibers, feedstock or combustion.


F.2.1.1.1.4 Process Materials Data

This function includes the conversion of raw materials to finished materials inventory, which is ready for storage, parts making, or consumption. It can include a series of chemical, electrolytic, mechanical, thermal, or other processes, either continuous flow or batch. Some measurable change in the materials properties needs to be made, but no special shaping or forming to designed parts. Thus generic metal bar stock is an output of this function. Because of the large number of materials and processes, this function is sub-divided further. Note that the same hardware may be used for multiple sequences and materials. This starts with a functional breakdown telling what needs to be made, the design telling how it is done follows.

Process Materials Requirements


General Alternatives

F.2.1.1.1.4.1 Process Stone and Concrete

This function includes preparing materials for direct stone use, in the form crushed stone for gravel beds and aggregates, sand or finer crushed rock for aggregates, filter, or thermal beds, larger rubble or dimension stone for construction, and indirect use as lime or cement.

Quantities

Cement makes up about 15% by mass of concrete, this requires 7.5% additional mined mass relative to final concrete ingredients. We estimated 2250 Habitation + 2250 Production = 4500 m3/year of concrete products during construction, which implies 1800 tons of cement, and thus 2,700 tons/year (7.4 tons/day) cement-making ingredients. The enthalpy of formation is 1.757 MJ/kg, and actual energy without heat recovery is about 3.6 MJ/kg. This requires an average of 308 kW power, or 4.1 kW/person/yr construction rate. This requires about 0.5 hectare solar collector area, if that is the energy source.

Design Alternatives

All cements need furnace heating to change the raw ingredients to the final product. The required temperature varies according to the ingredients. Metakaolin, derived from kaolinite clays, needs 500-800C calcination temperatures. It can be used to replace up to 30% of Portland cement without loss of strength. Pulverized Fuel Ash and Fly Ash are fine particles produced by fuel combustion, usually in power plants, and condense in the exhaust stream. They can also substitute for Portland cement. We do not want to generate power by burning fossil fuels, but alternatives are biofuel combustion and buying commercial ash products. Portland cement requires the highest temperatures to produce, about 1450C, thus higher concentration ratio of sunlight is needed, or supplemental heating.

F.2.1.1.1.4.2 Process Metals

In modern civilization, Iron and steel make up about 95% of total metals use. We can therefore treat this function as first supplying that metal, and then consider other metals as additions. Quantities beyond reinforcing steel are presently undetermined.

Quantities

Design Alternatives


F.2.1.1.1.4.3 Process Ceramics

This function includes preparing clay and sand for bricks, roof tiles, paving, household wares. It also includes other ceramic mixes for high temperature linings and containers, and carbides and mineral oxides for cutting and abrasion tools. The equipment to implement this function is shared with Process Stone and Concrete where the materials overlap.

Quantities

Design Alternatives

F.2.1.1.1.4.4 Process Glass

This function includes making soda-lime (ordinary) glass, and possibly specialty glasses using Boric or Barium Oxides and other additives.

Quantities

Design Alternatives

F.2.1.1.1.4.5 Process Wood

After raw wood in log form is extracted from the tree, it must be cut to the correct size pieces, and then dried to a preferred moisture level, typically 8-19% depending where it will be used. Because it is a natural product, it has variations and defects, and is anisotropic: having different properties like strength as a function of direction. The properties of wood also vary by species. Therefore pieces may be glued together with adhesives and reinforcement to form larger and stronger timbers and sheets as inventory stock.

Quantities

Since trees that supply good lumber take 25 years or more to grow, early construction will depend on existing forest inventory. A forest inventory of 125 tons/hectare @ average density of 0.7 green implies 0.8 hectare/person forest for initial construction. This is much larger than the sustaining amount, so either harvest rights, using the location land itself as a source, or buying excess land and reselling it would be options for the initial wood supply. A mix of these methods can be used. Sustainability will depend on replanting or selective harvest, to maintain a continuing supply. Once harvested, the "green" wood needs to start drying as soon as possible, and be protected from rot and moisture then, and thereafter.

Design Alternatives

F.2.1.1.1.4.6 Process Fibers

Natural fibers include items like cotton and wool. Growing and processing them to the point of threads and fabric are already large and mechanized industries, and we don't think we can improve on them enough to be worth doing. Sewing finished items from the point of fabric is worth considering. Synthetic fibers include glass, basalt, carbon, and polymers. These have a number of industrial uses as high strength reinforcement and insulation, and the quantities and market price make them a more attractive option to do internally.

Quantities


F.2.1.1.1.4.7 Process Electronics

Design Alternatives


F.2.1.1.1.4.8 Process Organic Compounds

Design Alternatives


F.2.1.1.1.4.9 Process Inorganic Compounds

Includes purified gases, liquid solutions, and solid inorganics. Metals extraction can be by thermal, chemical, or electrolytic means, the exact process depends on the ore and element being extracted.

F.2.1.1.1.4.10 Process Fertilizers

Design Alternatives


F.2.1.1.1.4.11 Process Water

Design Alternatives


F.2.1.1.1.5 Fabricate Parts Data


F.2.1.1.1.5.1 Fabricate Stone and Concrete

Design Alternatives


F.2.1.1.1.5.2 Fabricate Metals

Design Alternatives


F.2.1.1.1.5.3 Fabricate Ceramics

Design Alternatives


F.2.1.1.1.5.4 Fabricate Glass

Design Alternatives


F.2.1.1.1.5.5 Fabricate Wood

Design Alternatives


F.2.1.1.1.5.6 Fabricate Fibers

Design Alternatives


F.2.1.1.1.5.7 Fabricate Electronics

Design Alternatives


F.2.1.1.1.5.8 Fabricate Organic Compounds

This includes parts made from plastics, rubber, and related organic materials

Design Alternatives


F.2.1.1.1.5.9 Fabricate Inorganic Compounds

Includes parts made from non-metallic compounds not covered elsewhere.

Design Alternatives


Note:

Process subfunctions 10 Fertilizers and 11 Water are bulk materials, and not fabricated into parts as such. They go from process to storage or direct use.


F.2.1.1.1.6 Store Inventory Data


F.2.1.1.1.7 Assemble Elements Data


F.2.1.1.1.8 Grow Organics Data


This article is issued from Wikibooks. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.