Hot Water Systems

High pressure hot water systems heated up to 110 ° C and 180 ° C are called boiling water (hot water) systems. According to German standards, the limit for boiling water class is 120 ° C. A continuous counter pressure is created to prevent the water from evaporating. Therefore, the installation has no connection with the outside atmosphere. A closed expansion tank is used in the system. Hot water is a heating fluid that can be used in industry, building heating systems with fan coils, process heating and air handling units.

In hot water heating systems, the hot water boiler is completely filled with water and the desired degree of hot water is obtained. The hot water circulates through the heaters and releases its heat and returns to the boiler when cooled. The expansion tank should be placed at the highest point of the installation or in a place that can be seen in the boiler room. There is water up to a certain level in the closed expansion tank. When the installation starts to work, as the volume of the heated water expands, the water level in the tank rises and compresses the air at the top. As the pressure exerted by the air on the water increases, the boiling point of the water increases. The expansion tank must be pressure resistant and must have a safety valve on it. The water level in the tank is controlled with the help of a water level float.

If the hot water will be used for large-capacity zone and city heating, the water flow temperature may rise up to 180 ° C. Due to the high temperature, valves and armatures to be used in hot water facilities should be at least PN16 series.

The difference between flow and return water can be increased up to 80 ° C. Examples such as 160/80 ° C, 150/90 ° C, 150/70 ° C can be given among the temperatures used. When laying the primary superheated water network, there should be ventilation at the top and drain at the lower points.


Advantages of the Hot Water System compared to the Steam System:

  • Boilers can be 15-20% smaller than steam systems. Heat storage and network losses are less.
  • Pipe diameters are smaller than steam installations.
  • The system becomes simpler as the pressure reducing equipment (Steam traps, condensate pumps) will be removed.
  • The efficiency of the hot water system is higher. 10-30% cheapness is provided in the direction of operation.
  • In the steam system, network and system losses bring 15% transmission cost. In the case of a closed condensate system, these losses can be reduced up to 10-5%.
  • The steam trap and pressure reduction equipment in the steam system needs to be constantly checked and maintenance is required. This is not the case in hot water.
  • In open steam systems, corrosion and scaling stone occur in boilers and condensate pipes, and shorten the operating efficiency and life.

Equilibrium Pressure of Hot Water or Steam:

  • t=100×4/P(ata)
  • t=temperature to be obtained
  • P(ata)=P(atü)+1
  • P(atü)=manometric pressure value


The solutions we offer as Akterm Mekanik in hot water installation;

  • Hot water boiler installation
  • Hot water pipe transfer lines
  • Reactor heats
  • Hot water waste heat recovery systems installation and design