We have just about enough in the Objectives & Requirements Document for our Peak Oil Homestead Project to proceed with designing some suitable homestead concepts. Please keep in mind that you would likely want a few more requirements before proceeding with a design, but in the interest of time (and to keep everyone from losing interest) we’ll proceed with what we have.
This is a good time to note that one of the reasons it has taken so long to develop the methodology we’re using for the Homestead Project is that I’m working to adapt techniques to our small homestead more commonly used for large-scale industrial projects like the Space Shuttle. The underlying drivers are the same, but much of the available material has a much grander focus.
Now that we have plowed the road for applying Systems Engineering to designing for Peak Oil, further projects will flow much more smoothly. In the future we will design entire communities, constitutions, specific functional buildings (e.g. community medical facilities), and much more within a much shorter time span. So, hopefully you all have not lost patience with this process yet and are interested to see how all this designing plays out!
We’ll round things out with the following energy and water system requirements:
Water System Requirements
Input requirements
The water system shall obtain water from the environment.
Simple enough. Reminds us that no delivery truck or utility pipe should be part of the design.
The water system shall withstand no less than 30 days without precipitation with a minimum of damage.
The water system shall withstand no less than 30 days without precipitation without depletion of reserve resources.
The water system shall accept all human biological waste.
The water system shall accept TBD lpd of grey water.
Output requirements
The water system shall discharge treated grey water.
The water system shall discharge treated black water.
This directs us to provide a method for treating both grey and black water before releasing it back into the environment.
The water system shall provide no less than 280 liters/day of potable water.
The water system shall provide no less than 14,000 liters/day for food production.
These are traced from our top-level system requirements.
Interface requirements
The water system shall accept heat energy from the energy system for hot water production.
Suitability requirements
Reliability requirements
The water system shall have a system uptime of no less than 99%.
Maintainability requirements
The water system shall ensure that maintenance does not require damage the structural system.
The water system shall require less than or equal to 3 hours/week for support activities.
The water system shall allow maintenance by a person with less than 2 weeks of formal training.
It should be noted that this refers to routine maintenance and not expansion or other modification of the water system -- that would likely require more training and time.
Extensibility requirements
The water system shall be modifiable without damaging the structural system.
Trainability requirements
The water system shall provide instructions for proper use of the system.
The water system shall be usable by an adult with no prior training in its use.
Cost requirements
The water system shall cost less than $10,000.
Sustainability requirements
The water system shall operate in a manner that does not harm existing ecosystems.
Reminds us to consider the full effects of our design.
Electrical System Requirements
Input Requirements
The energy system shall obtain energy from the environment.
Output Requirements
The energy system shall maintain the living space temperature at 55°F – 85°F.
Interface Requirements
The energy system shall heat water to the levels required by the water system.
Suitability Requirements
Reliability requirements
The energy system shall have a system up time of no less than 95%.
Maintainability requirements
The energy system shall ensure that maintenance does not require damage the structural system.
The energy system shall require less than or equal to 3 hours/week for support activities.
The energy system shall allow maintenance by a person with less than 4 weeks of formal training.
Extensibility requirements
The energy system shall be modifiable without damaging the structural system.
Trainability requirements
The water system shall provide instructions for proper use of the system.
The water system shall be usable by an adult with no prior training in its use.
Standards and Protocol Requirements
The energy system shall comply with the 2007 National Electric Code.
Cost Requirements
The water system shall cost less than $20,000.
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Damn that intimidating
Damn that intimidating section notation for making me immediately close the link after I opened it, but now I reopened and am reading it, it's really not that bad. I'm impressed and committed to learning systems engineering now. I am reading John Seymour's "The Self-Sufficient Life", extremely thorough introduction to homesteading. I will learn something about how to meet the requirements from that.
Don't let the notation scare you!
Glad you didn't let the notation stop you. The notation is just a way to keep things organized so you can easily refer back to a particular line in the document. The concept of Systems Engineering isn't really that hard, but the specifics can be difficult to do right.
Within the next few weeks (if the imminent arrival of our baby boy doesn't interfere!), I hope to get a few possible designs done so we can look at how to do trade studies and select the best possible concept. Stay tuned...
I've heard of John Seymour's book and read some excerpts, but have yet to sit down with a copy. Let us know what you think of it.
couple of suggestions
It's been awhile since I read a requirements document like this. I used to work in DoD and it brings back lots of memories. On my last project in that world I was fortunate to work with a number of AEs, MEs, EEs, and several systems engineers. I really came to appreciate the concept of systems engineering. The systems people help pull all the pieces together in a coherent fashion and help spot little problems before they become BIG problems! The world is in desperate need of systems engineering because so many things are designed with such a short-term focus; little or no attention is given to longer term affects.
A couple of suggested additions to the requirements are a measure of the allowable soil erosion in a year, and a measure of the available organic material in the topsoil. Both items are major issues in our modern mechanized farming. Millions of tons of topsoil are eroded every year and carry with it vast amounts of nutrients and organic materials. Measuring these two items (there may well be other related requirements) could influence site selection and/or could establish further requirements for preventive measures. Such measures could include mulching, terracing, contour planting, and strip cropping.
I'm not sure what allowable limits should be for these requirements. I've got a couple of reference books that I'll dig through and look for other sources of information.
Keep up the good work!
Nice
Those are some really good points. We need to find both allowable measures for those quantities and a way to measure them that would be feasible for a person without much knowledge of soil science (also feasible post-Peak Oil).
Thanks for looking that up -- I'll see if I can come with something as well.