In this section the building, its analysed walls, the used measurement equipment and the test sequence are briefly presented. More details about the building and walls are included in (Porcar, 2004).

The building

The building analysed is being used as a workshop at the Plataforma Solar de Almeria (Tabernas, Almeria, Spain).

Its design includes some design strategies intending to save energy maintaining the desired comfort. The aim of these implemented features are the following:

• Overhangs size was calculated to allow solar gain into the room in winter, and to avoid it in summer.

• Windows have been diagonally placed to promote cross ventilation.

The building is being monitored to evaluate the effect of the implemented saving strategies, the degree of comfort achieved and also to validate simulation work.

Figure 1: Monitored building. Left: South fagade with window and overhang. Right: North and east fagades.

This building is very useful as it allows applying sophisticated analysis tools and due to its simplicity and high degree of knowledge about its construction, it is possible to apply different approaches and to compare their results.

Analysed walls

The opaque walls of the building have been analysed. Figure 2 schematically presents these walls.

SOUTH WALL E v 1 w

EAST WEST AND NORTH WALLS E [——————————————————— 1

ROOF

3 to 5 cm Concrete

25 cm polystyrene cove

Indoors plaster

8 cm hollow bricks

Air chamber

Projected Polyurethane (2 cm aprox.)

Ceramic block 20X20X40

Indoors and outdoors plaster using mortar (1.5 cm)

North, East and West walls are identical. South wall is also identical except that it has a wider air chamber and also a 2cm polystyrene (PS15) panel attached on the indoors surface.

Figure 2: Constructive schemes of the analysed walls.

Sensors

The following sensors have been installed:

• Four indoor and one outdoor air temperatures using PT100 four wire connected, protected from solar radiation and ventilated.

• Global horizontal and vertical solar radiation using thermoelectric pyranometers

• Heat flux density leaving the room through the ceiling, south, north and west wall using thermopile based transducers. All of them centred in each wall and embedded on its indoors surface.

• Relative humidity using capacitance transducers.

• Wind velocity sensors using optoelectronic transducers

• Wind direction using resistance based transducers

All these measurements have been read using a datalogger which A/D resolution is 16

bits.

Sensors where installed with the constraint that monitoring should not be intrusive and

taking into account that the building was being used as a workshop.

Meteorological sensors were installed near the building.

Test sequence

As it was intended to make compatible the normal use of the workshop with the measurements carried out, no tests strategy has been implemented in this case. However it is usual to use some kind of cooling or heating power to excite the system (Letherman et al, 1982).

In principle the normal use of heating and cooling devices could have been used for this purpose but due to the implemented saving strategies very low heating and cooling were required, so most of the time the building was in free evolution.

As weather conditions were the only external exciting signals available it was decided to use winter data for analysis, where these excitation signals were more powerful. So the following data were used:

Winter: Since the 20th of December 2003 to the 6th of January 2004. These data are graph in data in Figure 3 to Figure 6.

Figure 3: Measured Global Vertical Irradiance.

Figure 4: Measured indoors and Outdoors Temperatures.

Data were read each second, and averaged and recorded each ten minutes.

North and West Walls.

1 1 1 1 1 1 1 1 1 1 ,1 ,1 l’l ll л л 1 l,: ill II ll till ll 1 a i’j a * — V tjjj-w J4 ‘L L

5 — r 4 3

Time (DAYS) — South Ceiling

Figure 6: Measured Heat Flux Density:
Ceiling and South Wall.