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Thermal Disinfection Of Hot Water

Hygienically clean drinking water is delivered from the water supply companies to the premises. At this point, the responsibility for drinking water quality is transferred to the owner. It is up to the owner to ensure the proper operation and maintenance of the drinking water system. Poor operation and maintenance will significantly increase health risks by exposing the occupants to water borne pathogens.

Hot water distribution is a critical factor: If the hot water temperature in the house is constantly regulated and monitored, pathogens such as legionella have no chance of survival. For safe protection, high water temperatures of >55 °C are necessary. The German Environment Ministry considers a hot water temperature of 55-60°C necessary for hygienic heated water. Keeping within this range is also considered the optimum temperature range for energy efficient operation.

Benefits

Applications & Products

According to DVGW worksheet W551, a minimum of 60°C temperature must be reached in the hot water storage tank. Due to the circulation, the water must be returned to the storage tank at a minimum of 55°C. This task is carried out by a circulation pump. This ensures the required supply temperature is maintained and pathogens are killed. In order to realise the even distribution of water temperature, a controlled flow through all the pipes of the drinking water installation is necessary. As different plant components have different pressure losses, the differential pressures of the individual hot water pipes must be determined and adjusted by "adjustable resistors" in the pipe network. This hygiene calibration usually takes place by means of pre-settable control fittings. Where there is too much water, the water flow is slowed by the pre-setting.

Honeywell Home offers the right solution for every installation.

System with static hydraulic circulation adjustment

Through the installation of throttle valves, permanently adjusted pressure losses are balanced in the risers, thus permitting an even flow and distribution.

Advantages
  • Ensures an even temperature distribution in the lines in the design case
Disadvantages
  • Only applies to the design case
  • There are temperature differences within the floors
  • A complex calculation of the temperature and pressure losses is necessary for the pre-setting of the throttle valves
Alwa-Kombi-4 throttle valve V1810Y without thermal control set
  • Fitting for hydraulic adjustment in hot water systems
  • DN 15 to DN 40
  • Emptying via emptying adapter
  • Maintenance-free spindle sealing
  • Can be retrofitted with thermometer

Dynamic, continuous thermally balanced system

Through the installation of control valves with thermostatic temperature control, variable pressure losses are configured in a modulating way in the risers, thus permitting an even flow and distribution.

Advantages
  • Simple production of the thermal configuration, as only the desired temperature at the controller has to be adjusted and elaborate calculations are not required
  • Automatically self-regulating for all operating conditions and also supports thermal disinfection
Disadvantages
  • There are temperature differences within the floors
Alwa-Kombi-4 throttle valve V1810Y with regulator set VA2400A002
  • Fitting for hydraulic adjustment in hot water systems
  • DN 15 to DN 40
  • Can be retrofitted, automatic temperature control Alwa-Therm
  • Emptying via emptying adapter
  • Maintenance-free spindle sealing
  • Can be retrofitted with thermometer

Dynamic, thermally balanced system in terms of levels

Through the installation of floor levelling valves, variable pressure losses in all plant sections are configured in a modulating manner, thus enabling even flow and distribution.

Advantages
  • Simplest thermal balancing, since no adjustments need to be made
  • Automatically self-regulating for all operating conditions
  • No temperature differences in the whole system
Disadvantages
  • None
Alwa-Comfort regulation valve V1840
  • Very high control accuracy and fast response time due to the internal thermocouple, which is completely surrounded by water
  • DN 15
  • Pre-set at 57 °C or 63 °C
  • Minimum volume flow <0.1 m3/h