Deliverable 3.2. of the TEMPO project focuses on the actual execution of the more rural Windsbach demo-site and its key components.
To implement and operate an optimally functioning district heating network, coordination and a certain amount of heat storage capacity in each home are very beneficial.
As a consequence, a district heating network with higher-level control and decentralized buffers in every participating house was built in a development area in rural Windsbach, a town in south-eastern Germany. Decentralized buffers allow for a certain amount of thermal energy to be stored inside each house. Thus, demand peaks may be capped (“peak-shaving”). Consequently, the district heating pipes may be designed with smaller diameter. This allows reduced installation costs as well as minimized transfer heat losses.
The higher-level controller is able to manipulate the amount of energy stored (within comfort boundaries), further improving these effects.
Several assumptions had to be made for the district heating (DH) network in order to determine the adequate size of the district heating piping, the heat generators and the central pumps that transport the hot water to each house:
- The average energy consumption of single-family homes averaged over the day is about 10 kW or slightly more (depending on the building size), and about 40 kW for multi-family homes. Consumption peaks (e.g. for domestic hot water generation) are being attenuated by the buffer tank.
- Maximum supply temperature (in winter) is 80°C, return temperature will be significantly below 50°C. Together with the calculated maximum required heat power, this allows the layout of the network’s central pumps and pipe diameters.
Overall, approx. 3000m of pre-insulated plastic pipes have been installed. By the end of 2021, about 70 to 80 homes will be connected to the heating network.
(Image: Heating central in the north, main trenches in black colour)
The heat mainly comes from the combustion of renewable biogas in large motors, that simultaneously provide electricity (“cogeneration”).
It is distributed via semiflexible PEXa pipes with very good insulation.
Inside each home, there’s a buffer tank that stores hot water from the district heating network. This hot water is being used for the house’s heating, as well as heating domestic water instantly when it is required
A combined unit consisting of buffer tank, controller, pump unit, domestic hot water station etc. controls the necessary processes in the house. The heat consumption is determined individually in each house’s station, so that the heat supplier can charge each connection user exactly for the heat they have consumed throughout the year.
The network and the heating central are monitored to keep an eye on performance and possible errors. It goes without saying that no personal data is passed on in the process.
With the help of the monitoring programs, charging behaviour of each single unit, as well as the overall district heating network may be optimized.