Back to the Basics–Heating, Cooling, and Water All in One, by Mike C.

Description
A quick “how to” system that will gather air on one end, run it underground, and output it to another system that collects the moisture from it in order to produce drinking water while altering the temperature of a living structure to a level that can sustain life.  Please note that every house, landscape, and geographical location can be vastly different than the next and it’s therefore impossible to give a thorough how to, independent research must be conducted by the reader.

Introduction
Preppers have the amazing talent of separating need from want in life, and the need factor basically falls into two master categories – food and shelter.  Every other “need” need can be easily placed under one of these two headings since keeping things simple is also a prepper trait (e.g. water would fall under food even though it’s not food per se).  Overcoming the challenges of each category in the most efficient manner possible is one of the keys to survival, which is why buying the latest and greatest technology may not always be the best answer.  In fact, nature has provided a free solution to many survival dilemmas and in most cases it’s just a matter of piecing together the puzzle.  Take that same completed puzzle, wrap it in a shiny plastic housing, find a catchy name, and now it can sell for loads of money…there’s not a product out there that somehow defies the laws of nature and is original.
With these things in mind, a simple solution to keeping a structure at a suitable living temperature can be pieced together using the very basics of science and carrying a price tag ranging from extremely low to really no more than the price of a good used car.  A basic system of heating and cooling used today has an input, a temperature conversion, and an output.  Depending on the process there may be other outputs as well but most of those are based on mechanical processes and ultimately go to waste.  But what if multiple outputs could be generated and put to use in a more natural, efficient manner. See this illustration.

Gathering the Input
No matter where a retreat is set up, there will be varying temperatures, sunlight, and precipitation.  The simplest and most independent way to gather the needed input (air!) is to harness one factor and protect from the others.  In other words, a solar powered fan system with a housing to cover the actual fan components is going to be a simple solution to gathering said air.  There are many window mount, solar powered window fans on the market now and with some slight modifications these can become an air moving system.  Choosing which fan (and how many) is going to take some additional research because of the next step in the process…not to mention the actual square footage to be heated and cooled at the output level.   Calculating cubic feet per minute (CFM) against anticipated system length into the space cooled may not be everyone’s forte, so luckily there are plenty of web sites out there to assist in the process (even Sears has one) – after all, they are trying to sell an HVAC system.  While solar power is not mandatory in this case, it’s going to provide the most independent and renewable source of airflow.  The cost of solar room fans is also fairly low, and although they are not made to take a beating from the elements, once again some simple modifications in the form of a fan housing can extend their lives indefinitely.
Hiding the input is another consideration, for example four solar fans mounted in a small housing and blowing into a hole is not only interesting to any passerby but is also a direct path into your living quarters where even smoke from a fire could make life hard.  While keeping the panels themselves uncovered, it’s entirely possible to camouflage the rest of the structure – prevention is gold.

Temperature Conversion
At 4 feet below the surface of ground level at any given point in the more populous latitudes on Earth it is very likely that a constant temperature of 55-to-60 degrees Fahrenheit will be found.  The system used in this design uses that constant to cool or heat the inputted air.  There are some factors to consider in this design, especially in the long term.  Assume that a four fan system is pushing enough air into an 8 inch PVC pipe that drops 4 feet below the surface, zigzags across a 75’x75’ area (a typical backyard for example) using over 500’ of pipe and emerges at the other end with the output air.  If the air goes through too fast then it’s not given the chance to drop (or raise) to the desired level, and a lack of CFM would give off the proper temperature but only cool or heat the output area.  These are factors that have to be considered when designing the conversion area, even the thickness of the pipe.  Some other factors that are critical would be keeping it level, drainage, and making certain mold accumulation does not occur.  While this would all seem an insurmountable task, with the abundance of current technology and better yet, the qualified people in this field these are actually easily answered questions when it comes to design.  Picking out the site, having the facts about the site and designing the conversion chamber will be the easiest of the process.  Renting and running backhoe, laying pipe or venting with graveled bottoms, and attaching all the pieces together will be a bit more of a challenge.  Don’t hesitate to walk into smaller HVAC businesses and start chatting about such things, most people in this field become instantly intrigued and want to explore the possibilities.  Lastly, try and think ahead 20 years and consider what the system will have to endure, design it to last.

Drainage And Mold
The system described herein has not been tested for the long term.  A simple ditch structure with a brick tunnel might suffice in some areas while 8” pvc with drainage holes may be necessary in others.  I cannot stress the importance of preventing mold in a system that goes underground and obviously is capable of not only attracting mold spores but giving them a place to thrive.  The number one preventer in mold growth is to not have standing water. I suggest with the time we have that owners look at their chosen site for such a structure and begin some independent tests.

Output
The outputted air will carry whatever humidity there was from outside, and any accumulation that occurred while underground.  Once again, a single design cannot be expressed for the purposes of this document because of the plethora of variables.  It’s within the occupant’s bests interests to remove at least some of that humidity from the air for the sake of comfort and to convert it to drinking water.  A simple Internet search for “air well” reveals an age old design of collecting moisture from the air through the simple process of natural heat exchange.  Even the ancient condensation collectors discovered in long gone civilizations were efficient at collecting the water from the air.  A higher end design would include an actual powered unit that costs around $1,500 USD and will output at least 5 gallons a day…just have a generator on site to handle its power needs (a medium grade solar generator can easily handle this unit with power to spare).  Bear in mind that powered units will also produce a warmed air that goes above the ground temperature so that could be put into a very advantageous position for the retreat dweller.   In the event that nothing electrical is used on the output side and moisture were collected naturally then the 55-60 degrees would be enough to keep people alive, perhaps not comfortable, but ultimately only needing another 10-15 degrees to be in a good range.  Having a good way to measure hacumidity and temperature will do a person a world of good when fine tuning the system.

Conclusion
If TEOTWAWKI occurs, food and shelter and all their little subcategories will be our main concern.  If a person can dig a trench, hook a fan (or fans) on one end and on the other end enjoy the natural temperature of the earth then that person is already ahead of the game – and it beats living underground.  A few tweaks to the design might be in order depending on exact circumstances, but if a person sticks to the principles of simplicity then they are easily overcome and handled.   Perhaps one of the strongest selling points of this system is that it’s very versatile due to the fact that it can be integrated into almost any survival retreat or plan – no matter how great or small.  It can also be accomplished on a budget that is less than the average family output on dining out, or can become a professional endeavor that a person looking for a way to become self employed and all the more independent.  When a person successfully sheds the bonds of society’s “have to have” luxuries and gets back to the basics, it’s amazing what can be done.