Year 1 - What We Learned

ERTR - What We Learned in Year 1

In short, the Environmentally Responsive Test Room did not behave as we expected:

Insulation:
The ERTR was not insulated well enough. If it was cold outside and warm in the test room, the test room would lose about 1 to 2 degrees Fahrenheit per hour. This is too much temperature lost over night for the room to stay comfortable. Insulating the room further especially beneath the room may be the solution.

Glass Door and Awning Window:

The heat collected from the sunshine that came through the glass door and window was just barely enough to heat up the room on a sunny cold day and not enough if it was a cloudy cold day. Perhaps more of the room's exterior surface area should be more south facing glass than the approximately 5% of this ERTR.

Interior Insulating Curtain:

The curtain when covering the south facing glass had little effect on holding in the heat during cold nights as it only insulated approximately 5% of the room surface area and the heat loss through the wall, floor and ceiling were high. Also because the curtain was not sealed tight, solar heated air or air cooled by the cold glass could escape into the room. The insulated curtain might be better if it covered the glass exterior with a good seal. In addition, even when we prototyped with higher insulation on the window (thick blankets) it did not significantly reduce the heat loss from the room.

Solar Heating & Thermal Mass:

Much to our surprise the sunlight energy that comes through the south facing glass (as visible and ultra- violet light) in effect heats the air first, when it is re-radiated as infra-red light by whatever it hits. The hot air of the room is then the primary way any thermal mass in the room is heated up. Therefore the thermal mass should have as much surface area as possible. For example we found that 1 gallon water bottles were far more effective in absorbing heat from the air than larger drums or containers of water.

The Exterior Horizontal Sun Shade:

We found little opportunity to use the retractable sun shade. It needed to be a lot longer and wider to cast a useful shadow during the warmer months. In the winter, there was no need to extend the sun shade to decrease the sunlight as just barely enough sunlight was heating up the room as is. In the summer the high sun does not enter the room because of the fixed roof overhang and the sunshade offers little shade to the deck. Also the sun shade is likely to become damaged if extended in the wind.

Auxiliary Heating and Cooling: Realistically, to keep the room comfortable in the few days of extreme hot or cold, auxiliary heating (such as a small electrical space heated or wood fire stove) and auxiliary cooling (such as evaporative or geothermal cooling) should be considered.