The thermal performance of each test cells will be monitored continually from this winter until autumn 2007. The cells will be heated. So, sensors will be used to
- control and measuring the heating,
- determine temperature variation in various parts of the room;
- measure heat movement through the cells' fabric; and
- Monitor air movement in the roof and sub-floor spaces.
In addition, local weather conditions will be monitored and recorded.
Controlling the heating
The regulatory modelling program, AccuRate, estimates the amount of energy required to keep specific rooms at a comfortable temperature during different times of the day. To replicate this, the heater in each cell will be controlled by internal temperature sensor. Running time and energy use will be measured and recorded.
Temperature in a room is not consistent. It is influenced by height in the room, proximity of hot and cold surfaces such as walls, and draughts and other air movement. Temperature will be measured at three heights (0.6, 1.2 and 1.8 m high) at each of nine points in the cells. This is shown in Image 3 below.
Heat movement through the fabric
Heat moves through each surface of the cells, ceiling and roof, walls and floor. To measure this heat flow and the thermal performance of the construction systems, temperature sensors are positioned:
- At each material surface in the centre of the north and south walls;
- At each material surface in the centre of the ceiling and across the roof sheet on the centre of the north facing roof segment; and
- At each material surface in the centre of the floor. As the slab may use the ground under it as a heat sink, temperature is also measured one meter under ground in the centre of each cell.
Air movement under the timber sub-floors and in the roof spaces influences the flow of heat through the floor and the ceiling. Air movement sensors will be positioned in the centre of the floor and ceiling space of each module.
The collected data will be analysed to compare actual thermal performance to that predicted by AccuRate. This will provide a critical but objective comparison between the performance accessed by the rating software and the measured performance of three similar test cells.