ENERGY BY NATURE
9
VERTICAL-HORIZONTAL ORIENTATION
A domestic hot water storage tank, to function effectively, must have a good layering capacity, i.e. it
must have layers of water at different temperatures inside. What makes layering possible is the fact that
a fluid’s density changes as temperature changes: hot water has a lower density, therefore it tends to
accumulate in the upper part of the radiator while cold water, being heavier, is deposited in the bottom.
Layering is an essential prerequisite for the smooth operation of a solar water heating system.
The vertical storage tank prevents cold water from the water network from mixing with hot water
coming from the radiator every time water is used.
RADIASOL in vertical position has a diameter/height ratio well above the generally required standards
(2.5: 1).
The picture shows RADIASOL in vertical position (Figure 1) with an inlet water temperature of 15 °C. In
this condition three layers form, with respective temperatures 15 °C - 45 °C - 65 °C (indicative). In this
case 65 °C water is immediately available at the output.
In cold climates RADIASOL, installed in a vertical position, works on higher temperature ranges, also
greatly reducing the need to use any auxiliary heating source (heat pump or boiler) in colder seasons.
If a horizontal position installation is chosen (fig. 2) layering does not occur and, in the same climate
conditions, the output water is at 45 °C.
EDN recommends using RADIASOL horizontally only in climatic zones with insolation values above
2000 kWh/m2 per year.
For special installation and architectural requirements, contact EDN.
15°C
45°C
65°C
45°C
15°C
(image. 1)
(image. 2)
