The also patented so-called AL-LE-EPS-insulating system — Aluminium (AL) in combina-

tion with extruded polystyrene (EPS) featuring very low thermal conductivity (LE) — consists of a combination of reflective layers and a generously dimensioned insulating shell using environmentally amicable polystyrene (100 mm LE-EPS and 25 mm air). The insulation thickness of a total of 125 mm is unique in this market segment, additionally it features very low heat conductivity: Figure 3 shows the measurements of the ISE for different in­sulating materials in comparison to the measurements of LE-EPS (as quoted by the raw material supplier).

LE-EPS offers better values than all conventionally used insulating materials; its insulating values are even better than that of PU-foam (hard), while at the same time it is environ­mentally friendlier.

The insulation alone already reduces heat losses to 55 % of the losses of a 100 mm thick soft-foam insulation. Additionally there is a radical reduction of all further losses through heat bridges or microcirculation in the connection pipes: the tank is positioned on special insulating synthetic runners. Four connections leading to the outside are located in the cold bottom area while two heat-trapped boiler connections at the side are equipped with

PP-convective barriers thus reducing heat losses by about half when compared to con­ventional tanks.

Figure 4: Complete System