June 5th, 2012

Ann Vole

My calling in a box

My calling in a box
I feel strongly that my mission in life is 90% talking animals (real or fictional) and 10% self-sufficient living methods. The mission to become self-sufficient and to show the world how to be so themselves comes down to 70% how to make your own food, 20% how to be utilities-free, and 10% transportation (in terms of the impact those areas have on the world). Being that food technologies are very connected to utilities use, they become inseparable. Most of the energy losses can be accomplished with well known technologies of insulation and air-tightness so there is little for me to contribute there. Humidity control and air exchange (oxygen and CO2 levels as well as smells) are an area that is poorly handled in even the most modern buildings. When the inside and outside temperatures are vastly different and de-humidification is necessary (as is the case in both hot and cold climates), carefully controlled air exchange through an air-to-air heat exchanger becomes the key aspect. Occupancy testing is good for saving electricity for lights but far more significant is controlling the amount of air exchange through a heat exchanger. To increase air-tightness in even a poorly sealed wall or window, just having identical pressures on each side of that wall will keep the air from flowing through. A separate air-to-air heat exchanger in each room's outside wall will eliminate such pressure differences. In Saskatchewan (where I live), temperatures can drop to the -40 range (both temperature scales are the same at -40) so an air-to-air heat exchanger will be doing 2/3 of it's work below freezing and so must be designed to defrost. Many designs just cool to freezing point by heating the incoming air enough that the out-going air stays just above freezing point. My idea is to do the same but also have a second heat exchanger designed to work entirely below freezing. The two exchangers will then switch places on a regular basis. If these units are built vertically, the melting frost buildup can drop to the bottom and melt while doing the warm-side of things and while dehumidifying, condensation can drip to the bottom. The problem of course is to put one of these vertical units in every room. My solution is to make them flat and the two units placed side-by-side then have them located within the wall. If the outside connections are at the top of the unit, a perforated sheet of metal can act as a pre-heater (air enters the holes as solar heating of the metal starts convection flow upwards) The units also only need to operate in the day and the high efficiency ECM motors can handle a wide range of input voltages so solar cells placed in series can be used to power the units directly and in parallel with charge controllers that charge batteries. When a demand use is initiated such as a bathroom fan, kitchen range hood, or general smelly room "panic button", the power source can be switched to inverter AC converted to DC for a timed duration (and thus draw from battery power in a utilities-free house). The inverter and charge controllers need to be cooled but it would be good to add that heat to the incoming air. Batteries need to be exhausted to the outside air but also should be kept warm. Having the batteries and electronics located within the correct areas in this in-wall heat exchanger would work great. It can also be connected using high voltage AC to the lighting units that also communicate occupancy to the heat exchangers. Wiring going out to the solar panels can be sent out along with the air flow so the points of breaking the air-tight wall are reduced to one. The heating needs within the heat exchanger can be created with friction heat by hydraulic oil using the ECM motors or can also be sourced by thermal solar heaters (and oil is a good choice for heat transfer fluid in cold climates... lasts longer then antifreeze and pumps better then salts). I think I will design and build some of these units and see if I can get funding to start a manufacturing venture for these. Saskatchewan with extreme hot and cold weather and extreme wind would be a prime place to test these in conditions not expected elsewhere.