SUPER HEATED WATER FOR HEAT REGULATION
At normal pressure (760 mm Hg) water stays in a liquid form within temperature limits between 0° and 100°C; at 0°C it solidifies; at 100°C it evaporates.
It is necessary to maintain water in a liquid state even at higher temperatures (see figure above), to obtain an effective and efficient thermal regulation and to avoid scale formation.
Precipitation of calcium carbonate and magnesium carbonate (main components of the incrustation commonly known as LIME SCALE) is directly linked to temperature increase and is at its maximum near the evaporation point.
Water thermal regulation plants must be equipped with especially reliable devices to ensure the lowest possible pressurization in relation to the maximum temperature attainable.
The most significant water properties for thermal regulation include:
• the highest specific heat among common substances (1 Kcal/Kg/°C), which remains constant as temperature changes;
• heat transmission coefficient by convection is nearly double the value of oily fluids;
• best heat transmission by conduction, compared to oily fluids;
• heat transfer properties remain constant throughout a wide range of temperatures (unlike oily fluids, whose specific heat increases and whose heat transfer capacity decreases as temperature rises);
• non flammability;
• low cost: the water to be used is not required to have specific chemical properties except for a total hardness between 10 and 20°F (average hardness).
It is therefore possible to utilise suitably filtered water from cooling towers, wells, closed cooled loops.
CIRCULATION OF THE TRANSFER FLUID