5.2 - Personal Production: Functional Analysis

Analysis Approach

The next step in the Personal Production example is to divide the project into more manageable pieces that can be individually designed. The project's equipment will grow and evolve from a starter set, so there is a strong time element. Our first division is then into a sequence of project phases that meet increasing levels of the total goals and requirements. Part of the growth will be how many people are in the community the project serves, so the phases also scale in quantity of outputs. The equipment set is sized to meet the needs of a given phase, either in dimensions or number of units. Operations on a smaller scale in the early phases should also provide some feedback for later design improvements. The equipment is intended to directly support some of the hobby and home needs of the community. So defining where outputs like food, shelter, and utility services go, and how they are used, is an integral part of the project. We therefore include these items as part of our complete system analysis.

Our second method of division is into a set of functional tasks that describe what the project will do. We will accomplish these tasks with some number of design elements, such as pieces of equipment or a set of operating instructions. There isn't a one-to-one correspondence of functions to elements. A given task may require multiple elements, and a given piece of equipment may be used in multiple functions. A complete design includes all the designed elements necessary to perform all the functions.

At the conceptual design stage we have limited project staff, and we cannot examine every possible design alternative. Our goal is to demonstrate project feasibility, and leave most of the design variations and optimization for later project stages. We therefore start with one set of functional flow diagrams, and a limited number of design options. We also plan to follow the reference architecture laid out in section 3.4. Given more time and people, later design work can go back and look at improvements and variations on the initial concept.

Project Phases

Figure 5.2-1 illustrates the division of the project into expansion phases, starting with a conventional workshop, and six phases numbered 1A through 1F (you can click drawings for larger versions). Six is an arbitrary number of divisions for what is really a continuous expansion. We chose that number as a reasonable compromise between number of phases to analyze and complexity of the additions in each step. The diagram is a partial functional flow type. It illustrates the time sequence, but only shows some of the inputs and outputs. Functional diagrams show what activities need to be done, but do not pre-determine how. Selecting how to do the tasks is a later design step. Conventional shop equipment and new parts and materials are inputs from outside the project. For simplicity we only show operating the final Phase 1F after building it, but each of the earlier phases will also have production operations. Producing useful outputs is, after all, the main goal of the project.

The expansion process begins with building a conventional workshop in the lowest box. For now we assume it is located at a single site. We use conventional construction tools and inputs of lumber, sheet metal, etc. to assemble a building, install purchased workshop equipment, and build custom items like workbenches and storage units. The completed conventional workshop is an output from the first function box. We use the conventional shop tools, along with additional outside parts and materials, to build the first Phase 1A expansion elements. These will be a set of added equipment that can process more materials, make new kinds of parts, etc. These may include the first "Seed Factory" machines, which are custom designed to make more of themselves. The expansion may also include buying or building more equipment of conventional design. The loop marked "Phase 1A Expansion Elements" indicates as soon as a new piece of equipment is finished, it starts being used to help build more equipment. When the full set of Phase 1A elements are finished, we transition to the next function box and start building Phase 1B. As equipment accumulates, we must also expand the building(s), roads, outdoor space for solar collectors, etc. to support them. It is likely this will be at multiple sites due to the eventual scale of production.

We continue building expansion phases in sequence through the final Phase 1F. During expansion, our ability to make our own parts and materials grows, but our target is only about ~25% self-production at the end of the expansion. Therefore all the phases require significant supplies of new parts and materials from outside. The final box, "Operate Phase 1F Location" indicates the growth is complete according to the project goals, and outputs the desired range of products for the community. Since the operating life is indefinite (has no fixed end point) we also produce whatever replacement parts are needed for maintenance. This diagram does not show the outputs of final products, but all the expansion phases will make them, in increasing amounts over time.

Because we have not done more detailed analysis yet, we assume geometrical growth in community size in each phase. The minimum size is assumed to be a community of 25 people, with eight owner-operators. This allows one skilled person per major production function, and enough labor for early construction and assembly. The first group of people build the conventional workshop, then start to build new equipment for Phase 1A. The end of each build phase from 1A to 1F assumes a factor of ~2.175 growth in the community, to 55, 120, 250, 550, 1200, and 2640 people. The percentage of needs & desires met is assumed to increase linearly by 4% per phase starting at 1% for the conventional workshop, then 5, 9, 13, 17, 21, and 25%. The number of owner-operators is expected to grow slightly slower than the community size. This is because they are accumulating more capable equipment that can produce more outputs, and the ratio of community to owners can therefore increase. These assumptions require increasing scale and diversity of equipment and skills for each phase.

The owner-operators are not expected to design much of the custom equipment. Rather they are provided with designs and instructions, and in some cases actual hardware, from a previous research and development phase. The R&D can operate in parallel with the project phases. It would deliver product designs as needed, rather than all up front. The needs of the Personal Production project help determine what R&D is required.

Top Level Functions

To the outside world, the entire project can be treated as a single function box with inputs and outputs (see Figure 4.1-1). From within the design process, the edges of that function box are treated as the System Boundary, the logical division between the system we are designing and everything outside that we are not (see Figure 4.1-2). The inputs and outputs across that boundary can then be broken down into separate flows by type: Energy, Food, Water, Parts and Materials, etc. The question then becomes how best to break up the sub-tasks internal to the boundary into smaller pieces. We choose as our approach the reference architecture described earlier in section 3.4. This follows a produce-deliver-use concept. First we make the product or service that people want. Since the production area generally isn't where people live, it then gets transported to them. Finally people use product they wanted. So our first level of functions are making things (Production), using things (Habitation) and moving things (Transport).

This is not the only way you can divide up the tasks, but we think it is logical way to apply the rule of Functional Relatedness. This rule organizes functions that are more related to each other than to other functions into one group at the next higher level of a project. One reason for doing that is it places sequences of related tasks and the flows between them in a more compact and understandable layout. Another is optimizing groups of related functions is easier than trying to optimize everything at once. Changes to the related functions have less effect on the rest of the project, so they can be updated independently.

Lower Tier Functions

There is not enough detail in the top three function boxes to identify what external flows link up with them, and what the flows are between them. To find that out, we begin a process of breaking down each function into smaller parts, identifying their inputs and outputs, and repeating until we reach tasks and flows that are simple enough to develop detailed designs for. Rather than creating this breakdown from scratch for each of our four example designs, we adopt the one from the reference architecture in section 3.4 as our starting point. Box and arrow type functional flow diagrams help understand how the parts of a system are connected, but they don't have room for full descriptions or technical data. We link the additional information to the diagrams by using the same names and numbers within the diagrams as reference labels on the other data.

Since the factory will grow in phases by additions to the previous phase, we don't need to create a completely new set of diagrams each time. Instead, our higher level diagrams will be based on the completed project (Phase 1F). We will eventually make a version of the lower tier diagrams for each phase, showing what items were present in the previous phase, and what is added or changed in the current one. Therefore they represent slices in the time dimension of the project, with each slice showing the physical relationships at that time.

1. Provide Production Capacity

Production is numbered first among our three top level functions, because logically it comes before using the products for living space or transportation. In practice, though, the all three top functions will operate mostly in parallel. Figure 4.1-3 shows the bare breakdown into second-tier functions. The core of the production flow is the sequence from extracting raw materials such as ores, processing them into finished materials such as metal alloys, fabricating parts from those finished materials, and then assembling them into finished products. To these core steps, we add a control function to issue commands to the production equipment, supply power to operate them, and store inventory as needed between steps. Lastly we have growing organics as a separate item because living things perform self-production in a fundamentally different way than human designed equipment.

Again, there are other ways the Production function could be divided up, but we think this is a logical way of grouping related tasks. The numbering sequence is also arbitrary, but more or less in time order so that flow arrows will proceed from left to right. In this form the diagram is incomplete. Next, we need to describe each function in more detail and what the flows are that connect them. This defines the scope of the tasks that a given function includes. Rather then repeat the all the generic descriptions from the reference architecture in Section 3.4, please refer to those, and we will note differences and added details here.

Production capacity is intended to evolve across the expansion phases. If we start with an early production step, like extracting raw materials only, we cannot deliver a useful finished product, because the later steps are not in place yet. So instead the evolution starts with the last steps near final delivery. Since the earlier production steps are not in place at this point, we have to buy parts and materials that are closer to finished. For example, if the product is a piece of furniture, we would start with buying ready lumber and hardware from outside sources, then fabricate parts and assemble them. In a later expansion phase we may work backwards and add logging and a sawmill to lower the cost of materials. If the product were a room addition to a house, at first we might only have carpentry and masonry tools to assemble the room. The excavation and foundation work would come from outside sources that have the larger and more expensive equipment. Later on, we could build our own digging and mixing machines to do those steps.

1.1 Control Location - This function provides overall control of the Personal Production sites and systems, including production, habitation, and transport. It takes as input the designs for the locations, and for end products, which are provided from the previous R&D phase. The degree of automation in the control systems starts out low for the conventional workshop, and will increase by phase.

1.2 Supply Power - This function is to supply all forms of power for the project, and converting it as needed to other forms. A significant surplus is an end goal. We expect to use conventional utility power at first, adding solar furnaces for direct heating and thermal storage, and photovoltaic, wind turbine, and bioenergy systems later to increase renewable sources and reduce outside dependence.

1.3 Extract Materials - This includes local supply of raw materials, using Personal Production equipment. The project goal is to obtain a significant share of total materials from new local supply, internal recycling, or from outside waste sources. As the space required grows beyond home garage/basement scale, project members may need to build new sites. Therefore conventional heavy equipment or self-building such equipment is an early priority.

1.4 Process Materials - This includes conversion of raw materials to finished materials inventory. Inventory is ready for storage, parts making, or consumption. The conversion can use a variety of chemical, mechanical, thermal, electrical, or other processes, and operate as a continuous flow or in separate batches. Early outputs may include concrete, basic metal shapes, glass, and wood for basic construction, with other products added later.

1.5 Fabricate Parts - This takes as input finished materials from processing or storage, plus outside materials supply. These are transformed into finished parts ready for assembly. Early processes for this function can include casting metal, glass, and concrete shapes, and machining wood and metal parts. Additional machines and processes would be added during expansion phases.

1.6 Store Inventory - This task includes storage for materials, parts, and completed items not currently in use. It includes storage for other Production functions, and long term storage for Habitation and Transport. Because of similarity, we also group environment protection and control (i.e. buildings) for the other production functions, and land for industrial tasks under this heading.

1.7 Assemble Elements - This includes combining parts and materials into higher level assemblies (collections of parts), leading to completed elements. It also includes dis-assembly of elements for maintenance or modification. Assembly includes making movable elements like production machines and vehicles, and construction of fixed elements such as buildings. At first, most of the parts for assembly will come from outside sources, with the percentage decreasing through the phases.

1.8 Grow Organics - This includes growing microorganisms, plants, and animals to the point of harvest. Pets and ornamental plants not included in this category. They are placed under Personal Items in Habitation. Growing organics includes the land space to grow biological products, including within Habitation areas. This land includes owned, leased, and harvest rights. Land may start out undeveloped, and used for extraction before upgrading to other purposes.

2. Provide Habitation Capacity

The Personal Production project as a whole is intended to satisfy some of the needs and desires of the owner/operators and the local community. This includes necessities like food, shelter, and utilities, and some optional items for hobbies and entertainment. The Production functions provide the physical items and primary services. The Habitation functions supply the locations where they are used. Habitation includes all types human-occupied space outside of production and transport tasks. Production and transport may include habitation elements. For example, a factory building may include restrooms for the people working there, and a passenger vehicle may include heating and cooling. They are included by necessity, but they are not the primary purpose of those elements. Conversely, a kitchen is a materials processing area, and may share equipment types like furnaces (oven) and mixers with the production area materials processing. But the end purpose of a kitchen is to provide food and drink to people, not to make other kinds of products, so it is put under the Habitation heading.

Habitation includes residential, commercial, and public use space. Buildings share common parts, like foundations and roofs, regardless of their use, and some buildings can be mixed-use. Therefore our functional breakdown is by type of human needs being met rather than by purpose of the building. The natural environment is often uncomfortable and sometimes hostile to humans, so we create shelter to modify the environment to our liking. Functionally we divide this into passive elements that protect us, and active elements that control and modify the local environment. Once we have safe and comfortable surroundings, we next provide for the internal needs of the human body in the form of food and drink, and maintaining health. Basic items like shelter and food are necessary for everyone to live, but beyond that the majority of most people's time and occupied space is taken up by other activities which are more optional and diverse. We divide supporting these activities into the physical, which are personal items like furniture and clothing, and information, which is not tied to a specific physical item. Once we define these various functions in more detail, their required inputs and outputs then become demands which the production function needs to meet.

Personal Production has a goal of supplying up to 25% of what people need and want by the end of Phase 1F. So the majority of the next tier functions listed below are supported by conventional means, like paid jobs, savings, and retirement income. Early habitation buildings are either already occupied by community members, or bought from the market. In the later project phases, we can start to upgrade and build our own. Later in the design process we will determine which products and services are easiest to provide and give the most return for the effort put into them. Those then get priority to implement first.

2.1 Protect from External Environment - This includes passive protection of people and other habitation elements from weather, water, insects, and other outside factors. It also includes structural support of all habitation elements, the underlying land for it to rest on, and outdoor protective clothing.

2.2 Control Internal Environment - This function covers actively managing the internal environment created by the protective shell in terms of temperature, humidity, lighting and other factors. It includes controls and sensors, the active hardware which produces the environmental changes, lighting, windows, window coverings, and emergency systems.

2.3 Provide Food and Drink - This includes supply of food and drink materials at the point of use, local storage, food preparation, serving, dining, and disposal of food and drink wastes.

2.4 Maintain Health - People are included as an essential element of the project. This function is the most relevant place to account for them and their inputs and outputs. It also includes tasks for sleep, sanitation, exercise, cleaning of persons, cleaning the internal environment, filtering, health monitoring, first aid, emergency services, and examination and treatment.

2.5 Provide Personal Items - This includes the internal volume of private living and storage space, public/community space, and commercial space. It also includes the physical contents of all these spaces and decorative/non-protective clothing.

2.6 Provide Information - This includes communications, storage, and processing in all forms, for personal, commercial, teaching, entertainment, or general information. It does not include operational information for production, although they may share hardware and software elements.

3. Provide Transport Capacity

Transport is the third top-level function. It is required because sources of supply, locations for production, and final points of use can all be different. Only part of the community's needs and wants are being supplied by internal production, so we need to import the remainder from outside sources. We also need to deliver some items for trade or sale, move items internally at a site, and community members need to travel from place to place, for work or by choice. All the movements may use similar types of transport elements, so we organize their lower tier functions by type of item transported rather than where it is going. Transport elements can be mobile or fixed (like roads), and they can be owned by the project or by other entities. Project-owned elements can be custom designs, while non-owned elements generally are not. One shared design, like a utility truck, may serve different cargo types. The functional division of tasks allows analyzing the needs for each, then considering specialized or shared equipment to satisfy them.

Like Production and Habitation, only part of the community's total Transport needs are met internally by project elements, with the remainder provided by conventional methods. The functions below represent the total needs. Later design work will determine which parts will be met by the project.

3.1 Transport Bulk Cargo - This includes bulk solids, both incoming and outgoing, or being delivered between project sites. It includes items for sale, or to use internally for expansion and maintenance. Bulk items don't need special packaging or protection during transport.

3.2 Transport Discrete Cargo - This includes individual items that need protection from the environment, shocks, and vibration during transport. They may need special packaging to protect items from each other. Discrete cargo is typically smaller, so multiple items may be delivered in a single shipment.

3.3 Transport Humans - This includes the transport of humans between project sites, and to and from outside destinations. It also includes internal transport within a site, but the scale of sites in this example mostly will not require it. Humans have many of the same needs as discrete cargo, plus a desire for higher safety levels and comfort, schedule priority, and optional manual control.

3.4 Transport Energy - This includes wired and wireless distribution of electricity, and portable sources like batteries and stored thermal energy.

3.5 Transport Fluids and Gases - These items require closed containers or fixed piping for delivery. It includes items like water, natural gas, and liquid fuels.

3.6 Transport Data - This includes all types of data in all forms, electronic and non-electronic. Legal rights and money are delivered via data so they are included here.