At the end of last week we had a good meeting with Murphy’s Cell-Tech, our energy consultant, who has done the thermal modeling for our house to determine the number of BTUs entering and leaving. The people involved in the model included experts in insulation, thermal seal of the building, heating systems, air ventilation, and renewable energy sources.
The basic idea is to use the sun to fill (heat) a storage tank in the ground with the amount of BTUs that will be required all winter to keep the house warm. The better insulated and air tight the house is, the fewer BTUs that will be needed to keep the house warm. To ensure healthy air quality, there will be a heat exchanger ventilation system which is always drawing in air from outside, pre-heated by the warm air from inside that is on its way out.
So the items that go into this model include the level of insulation in the basement (R26), walls (R40), windows (R10), doors (R10), and roof (R80). Then you have to factor in the amount of air you would like to exchange (150 cubic feet/minute for this house). Then calculate how many BTUs can be stored in the tank, the number that can be delivered on a daily basis by the evacuated tubes (about 140,000), and the number and speed that the BTUs will be drawn off to keep the house warm.
I started a page this week to summarize the goals, and provide links to the most recent updates and pictures. It is called “78 Main St – Renovation” and you can get to it from the main page below the full width image of a house with a solar panel, or from the “Visit Our Store” links.
We hope to start excavation for the storage tank the week of August 24th!