Pre-insulated twin pipe systems for district heating
The demands on modern heating infrastructure are increasing – particularly in urban networks and complex construction projects. Pre-insulated twin pipes offer a smart solution: they combine the flow and return lines in a single district heating pipe, enabling a compact, thermally efficient, and sustainable design. aquatherm energy twin builds on this principle as a consistent further development, providing a future-proof solution for district heating systems.
The world's first PP twin pipe system in dimensions 32 - 125 mm
aquatherm energy twin simplifies installation and optimises the operation of modern heating networks. By integrating the flow and return into a single casing pipe, it saves time, energy, and costs – making it the perfect solution for urban areas and complex projects.
| Advantages | |
|---|---|
| Space-saving installation | A narrow trench is all that is needed to lay the supply and return lines together – ideal for urban or confined projects. |
| Reduced construction costs | Lower excavation volumes and minimised material requirements significantly reduce construction costs. |
| Shorter construction time | The supply and return lines can be laid simultaneously, saving time and reducing logistical effort. |
| Minimised heat loss | The double system provides optimised thermal insulation, lowering energy consumption. |
| Lower weight | Easier handling due to lower weight compared to steel pipes. |
| CO2 savings | Polypropylene pipes have a lower CO₂ footprint as they are more energy efficient to manufacture, lighter to transport, and fully recyclable. |
| Durability | Resistant to corrosion and incrustation, both internally and externally. |
| High temperature resistance | Operational at temperatures up to 75 °C and briefly up to 100 °C – ideal for demanding applications. |
Like all aquatherm energy pipes, aquatherm energy twin is also available with integrated leak detection. Leakage monitoring continuously or periodically checks the system for leaks, enabling even the smallest issues to be detected at an early stage. This minimises water loss, environmental impact, and potential operational failures, while also reducing maintenance costs.
The diameter of the PP pipe determines its location and intended use. To ensure proper installation, the diameters of the individual pipes and fittings must be compatible, allowing a continuous connection from the supply point to the outlet.
A wide range of dimensions for every project: aquatherm energy twin is available in dimensions from 32 to 125 mm. For larger requirements, aquatherm offers single pipe solutions up to 355 mm.
aquatherm energy twin consists of several material layers that provide unique strength and insultation properties.
- Medium pipes made of PP-RCT
Manufactured from durable polypropylene, these pipes offer outstanding temperature and pressure resistance as well as reliable corrosion protection. - High-quality insulation
High-quality PUR foam fulfils the requirements of DIN EN 253 and, in combination with the excellent insulating properties of PP-RCT, minimises heat loss. - Robust PE casing pipe
Provides reliable protection for the insulation against external influences such as damage or moisture. - Effective oxygen tightness
Thanks to the diffusion barrier, the OT layer effectively prevents oxygen ingress and ensures long-term protection of the system.
The SDR (Standard Dimension Ratio) is an indicator of pressure resistance. In order to guarantee a certain pressure resistance, a certain maximum SDR number is required, depending on the type of material. The following applies: the greater the wall thickness, the lower the SDR number and the more pressure-resistant the plastic pipe. The unit indicates the ratio between the outer diameter and wall thickness of a pipe. aquatherm energy is available in the following SDR sizes:
SDR 9: Ø outer carrier pipe: 32 mm / Ø outer casing pipe: 180 mm
SDR 11: Ø outer carrier pipe: 40 - 125 mm / Ø outer casing pipe: 200 -500 mm
The polypropylene carrier pipe from aquatherm energy offers several advantages over conventional steel pipes:
- Low weight
- No corrosion
- High stability
- High impact resistance
- Less roughness inside the pipe
- Resistant to most chemicals
- Very good welding properties
- Self-insulating
District heating is widespread in Northern Europe, particularly in the Scandinavian countries, and plays an important role in heat supply. This is demonstrated by a project in Denmark in which aquatherm was part of the solution with its twin pipe system: aquatherm energy twin helped reduce construction costs and excavation volume for the pioneering project in Holbæk, while also significantly shortening construction time.
In the town north of Copenhagen, more than eight kilometres of the pipe system were installed to connect around 400 houses to the local district heating plant. The pre-insulated pipework system ensures that hot water is transported safely and with minimal losses over long distances, providing the entire housing estate with a reliable and cost-effective heat supply.
Denmark is pursuing a nationwide strategy to significantly increase the share of district heating – particularly from geothermal energy. Today, 64% of all Danish households are already connected to a district heating network, which is among the highest figures in Europe.
In Veksø, north of Copenhagen, around 400 houses are connected to the local district heating plant. The distribution of tempered water via the pipe system plays a central role here, as the network extends over more than 15 kilometres. Optimum thermal insulation of the underground pipes is crucial to minimising the heating plant’s energy requirements and supplying the housing estate efficiently.
The operators opted for the pre-insulated PP pipe system aquatherm energy twin, which stands out for its outstanding insulation performance, high flow rate, and lasting corrosion resistance. Compared with metal pipe systems, it offers greater efficiency, enhanced safety, and an improved environmental footprint.
