March 26th, 2007

Ann Vole

home = place where past and future meet

There is a quote I just read that struck me as the key to my designs:

"A nest is a cup of space, a [insert a few example bird nest locations]... It represents a still point in a bird's fast-paced life, the place where past and future meet" - Gretel Ehrlich

When I was taking instrumentation classes, we were designing control systems to eliminate cycles so the desired variable would require the least amount of controls to maintain the desired set-point. This way, if the control system failed to work, the output would at least be close. The control system also requires the measured variable to be wrong to know that corrective actions need to be taken. The less corrective action needed, the more often the variable will be the same or very close to the set-point. The best way to cancel a cycle is the use of "dead-time". Think of dead-time as the flow of the variable is required to travel some distance. For example, a conveyer belt may receive more product on one end of the belt but it will take some time for the increased amount of product to reach the other end of the conveyer belt. If the need for the product cycles up and down every 2 minutes and the coveyer belt takes 1 minute to move the product, the measure of that need will be too high at the peak of the measure of the product but no problem because it is only the amount added to the end of the conveyer belt. One minute later the meeasured product will now be at the low point in the cycle and the product has moved across the conveyer belt, the amount matching the higher level measured one minute ago. As you can see, dead-time needs to be designed to be 1/2 the time span of the cycle. House heating and cooling has three cycles to consider: the artificial delivery system (the furnice or air conditioner turning on and off), the outdoor temperature swing from day to night, and the seasonal cycle from hotest to coolest part of the year. Pure dead-time does not occure often in nature but there is a different variable that can act like dead-time. "Intergation" as far as the instrumentation engineer is concerned is the averaging of a variable with the use of a holding tank and a restriction to flow. In our previous example, we can replace the conveyer belt with a tank that can hold the amount of extra product that the high demand part of the cycle needs compared to the low part of the cycle. This holding tank will have a restriction on the bottem to give the average amount needed if the control system fails (or if the variation is close enough). you can see how these ideas are bringing past and future together.

For my heating system design, I will try to use dead-time of having heat travel through walls as much as possible but otherwise use storage tanks of heat or cool with an appropriately sized restriction to the flow. As you can see, such a system can be made to be completely automated and have no need for specific control systems if designed right. Most designers of passive solar structures use thermal mass in the method equivalent of a sponge... The holding capacity enters and exits from the same opening (the outside surface of this thermal mass stuck in a room). The heat flow will only happen when there is a temperature difference so the amount of thermal mass needed is much higher to maintain the temperature range of the room within acceptable limits. If they varied the temperature on one side of a thermal mass with resistance (higher "R-value"), the heat will take time to flow through. If that equivalent dead-time matches a cycle (furnice cycling, day-night cycle, or summer-winter cycle), the temperature on the other side of that mass-resistance structure will be the right temperature at the right time. I hope to do my "furnice cycling" on a time span that will allow time between cycles to equal the time the sun is not shining so fans and such can be solar powered. In the summer, this cycle can be short but in the winter it will have to be once a day if usable sunlight happens for less then 12 hours a day. This will happen in the wall between the rooms and cavety before the outside walls. This cavety will be the "radiant everything" idea I posted earlier. The day-night cycle will be absorbed by the structural walls to make for a smaller difference outside of that structure across further pure insulation to make maximum use of that insulation. The walls will be clay-straw mix or similar combination of mass and thermal resistance to match the temperature swings from day to night. The pure insulation will be added outside those walls to up the R-value of the walls to considerable levels and to protect the clay-straw structure from moisture penetration and pests and vandels. If the walls are designed for the day-to-night temperature swings, the effective R-value of the outside insulation will be seeing the average temperature difference between indoor temperature and the AVERAGE outdoor temperature for that part of the year. The heat loss should be considerably less for the same amount of insulation. The yearly dead-time is a bit more technical and is explained better in John Hiat's book "Passive Anual Heat Storage". I have a whole bunch of ideas but I need to think them through better and crunch some numbers and then make a few prototype designs and test them with real buildings. There is a promise of software that can do computer models of heat flow through the ground but it is new and tailored to the Ground Source Heat Pump people connected with IGSHPA. I may not be able to effectively change the system to check the one-way flow of heat and cool through a strip of dirt in a complex 3D arangement.
Ann Vole

Fly in the ointment of eco design, and the flyswatter

I have been pouring over dozens of books and hundreds of example real buildings that are beautiful, healthy, and energy efficient but every single one of them has the flaw of needing artificial heating or a good southern exposure (for a fully passive solar system). The other flaw often seen is the need for the occupents to do some action to maintain conditions year round (open and close shutters, make fires in the fireplace, adjust heating system or cooling system elements or even to choose which system needs to be used). I can see my ideas being integrated into almost every design without any visual of functional changes to the rest of the design. I do not need to show people how to do those aspects (passive solar, local materials, healthy materials, multi-use and minimalism) because books and instruction groups and companies are already showing, teaching, and selling that stuff. It is only the passive annual heating and dead-time cancelation designs that need to be taught (and taught to just about every "eco" designer out there currently). This system also has to work for people looking to build or live in a "normal" looking square, drywall and plastic siding type house on a normal city street and never need to do anything but live in the house... No special instructions for the occupants, no special building materials or methods, no strange new looks so it can be identical to the other houses on the street... All that eco stuff is optional. Again, looking at all the material on heating systems for "normal" house designs in these courses I am taking mentions any of this stuff I want to add (nor does any of my additions violate code if done with modern materials and methods... it is just never done that way). I need to get people seeing the unique advantages of this system and offering the courses and certification to do it right in everybody's favorite building designs and with their favorite building materials. All I do is eliminate the furnice/air conditioner/fireplace/hot watter tank, and maybe replace the stove, fridge and freezer with energy-free versions too. Go ahead and keep your fireplace or your microwave but you will not need them for anything but personal satisfation (fire is beautiful and mood setting and microwaves heat your hot drinks back up in a few seconds). All the rest of the house can be all eco-green stuff or can be standard drywall, it will still work.
Ann Vole

Sin offerings required for very specific "sins"

In Leviticus 5:1-6 there is a list of things that require a sin offering to be made. I am always interested in lists of good or bad things people should or should not do. This list is quite different then the others so it peaked my interest.
sin offering required if:
- failed to testify in court
- touchs something ritually unclean or something "of human origin"
- someone makes a careless vow ABOUT ANYTHING

And that is it... Just those three things (presented as four things as touching something "of human origin" was considered different then ritually unclean objects like dead animals but I consider them about the same). Jesus said to never make vows and there are many examples in the Bible and in classic folk lore (Greek gods in particular) where making vows caused major trouble. It is interesting that this "sin" of making a vow is listed here but not in the 10 commandments. Makes me wonder if the first tablets God made and that Moses broke were a bit different then the ones Moses made to replace them (like the Monty Python skit where Moses presents the 15 commandments then drops one of the three tablets..."15... er... 10 commandments). The commandment "do not lie" was changed from the original "do not bear false witness". Bearing false witness is a specific kind of lie where you falsely accuse someone of something. It is interesting that this not giving evidence in a trial and withholding something you have seen or heard is a kind of inaction that results in the same injustice as bearing false witness does. The sin is the same and the damage to the creation of a free and just society is the same.