Bought a new battery!

I bought a new battery to run my fan system. The one that I have been using was quite old, probably 5 years at least if not more. I was trying to save a bit of cash by using the one from my tent trailer, but it wasn't holding it's charge. So $100 dollars later, I will get a better idea of how well the tubes perform with a fan drawing the air constantly.

Cabin shell is close to lock up!

So the shell  of the cabin is close to complete. I will be building a loft, deck, pergola and small kitchen area. At this point though I'm simply worried about the building envellope. I want it to be good, but it is tough having used windows and lots of culled lumber from thesale piles. I will take my time with the finishing, interior and exterior once I get to lock up. I'll probably work on it this winter. For now, I need to start worrying about school, and I will be taking my LEED green associate exam soon. I am looking at a new battery, not sure if my battery is the problem, or wether or not I need more panels. I will relook at my calculations to see where I went wrong. The cabin has a nice feel to it though. I'm looking forward to having it done. It won't win any awards, but will be a good getaway.

Fan system is great for cooling air!

So the battery I have to power my system is not holding a charge long enough. However, for the hottest couple of hours that it ran today, it brought the air temperature down to 20 degrees celcius. Pretty good I think. I was pondering how useful it would be in a system with a furnace. On a thirty degree plus day, consistent air coming into the home at twenty degrees would certainly make a building far more comfortable for very little energy use.

Photovoltaic system and fan!

Well the little photovoltaic system I set up is working great. The fan is a little stronger than I'd like, but would do well in a larger building. I don't have data on it yet, my battery wasn't holding a charge for long enough. I have it charging and I am hoping to get some data with the fan running continuously. I want to see what effect a faster airflow has on the temperature.

Here is a graph of the potential of an earth tube system for your home or building.

The orange line represents the air temperature, the blue line is the air temperature entering the building, that has been conditioned by the underground temperature . The yellow line is the temperature deep inside the tubes. I have found that it fluctuates between 16-18 degrees. I will be trying to get a better measurement, but for now it serves as a good guide for when the outdoor temps have been high during the day. As you can see from the graph, the cooling potential for this type of passive system is significant. One of the positive offshoots of the system, is the potential for heating applications as well. The temperature differentials are not as large, but as you can see, the potential is there.

Solar system for running fan.

Here is the set-up I built to run my fan. The whole package cost about $150 for all the parts. I took the battery off my tent trailer, since it is meant to be drained and recharged. The panel is from Blue Planet, it is rated for 5.5W with a current of 400mA @ 15V. It is ideally suited to recharge a 12V battery. The Inverter is a small one from Canadian Tire and was one of the cheapest I could get.  Here is what the set up looks like. Missing is the fan which has been wired with a regular plug-in, which is plugged into the inverter. The battery is used to keep it running at night, and the panel runs the fan during the day and recharges the battery.

Here is the fan for the tubes!

I don't think I have posted the fan system for my blog yet. It is a small 4" fan that I purchased at Princess Auto. A computer fan would probably be best, since it probably uses less power. I will post photos and drawings of the power system I rigged up to power the fan soon.