House connection station

from Wikipedia, the free encyclopedia
Heat transfer station of EVN heat with an output of 300 kW a residential complex, a so-called indirect house connection station

A house connection station (HA station, HAST) serves as a transfer point for district heating from the energy supplier to the building being supplied. This then supplies the central heating . A distinction is made between direct and indirect house connection stations and the way in which the energy carrier media (steam or water) of the energy supplier is treated in the building supplied is classified.

tasks

The task of a house connection station in the building is to control the heating and hot water preparation (WWB) for the respective building. The flow temperature and output are regulated depending on the outside temperature. The characteristic curve of the flow temperature, which depends on the design of a building, is also known as the heating curve . The values ​​for the flow temperature vary depending on the system and are determined by the operator.

The basis for the parameters is the operator's duty to ensure a temperature of 22 degrees with an outside temperature of -14 degrees within the residential units (with the thermostatic valve at the maximum position).

The hot water preparation is used to heat the cold drinking water. A flow temperature of 60 degrees Celsius is specified as the target value for small systems (<400 l storage volume). A prophylaxis against Legionella infection by heating the system to higher temperatures is not a requirement. However, if Legionella has been detected in the system, thermal disinfection of the system is a possible remedial measure. According to DVGW worksheet W 501, a temperature of 70 ° C in the system is required for this and this must be verified for 3 minutes at each tap.

Direct house connection station

Destroyed shut-off valve of a water pipe due to the effect of frost

In the case of the direct house connection stations (HAST), also known as the primary station, the water from the energy supplier is fed directly into the heating system of the consumer, i. H. Apartments forwarded. The regulation takes place via control valves (e.g. differential pressure regulator ) which reduce the available heat by reducing the mass flow .

The risk of a tube fracture is that through the central water make-up a lot of water is pumped into the pipe system of the energy provider arbitrarily and the entire house is placed under water. Water losses are normal in large pipeline networks. The water loss in the event of a pipe break in the house is minimal in relation to the normal losses and would therefore not be noticed by the network operator.

This type of connection is no longer implemented across the board due to the risk of a pipe break.

Indirect house connection station

In the case of indirect house connection stations (HAST), also called secondary stations, the heat from the medium is transferred via a heat transfer station (WÜST). This reduces the length of the utility company's piping in the house and the risk mentioned above. The water distribution via pipelines in the building is realized through a separate water circuit.

The energy supplier's medium is located on the primary side of the heat transfer station and the separate water circuit in the building is located on the secondary side. This has its own make-up. In this case the water make-up can be adapted to the size of the following network. In the event of a pipe rupture, the network would run empty and would be deactivated if the pressure fell below a minimum ( ).

Components

A house connection station consists of the following components: