Solar stainless steel double pipe, bellows TWIN

Product detailed description

This pre-insulated stainless steel twin pipe system is designed for the installation of solar thermal systems, particularly for connecting solar collectors to storage tanks or heat exchangers. The system is commonly used in residential and commercial buildings where solar thermal energy is integrated into the heating or hot water supply. The flexible and durable design allows for installation through existing unused chimneys or ventilation shafts, making it suitable for retrofitting older structures. The system is ideal for use in solar thermal installations where high flexibility and thermal efficiency are required.

The HPW® TWIN system is engineered to handle the thermal and mechanical demands of solar thermal applications. The stainless steel corrugated pipes ensure resistance to corrosion and thermal expansion, while the EPDM HT insulation minimises heat loss and maintains system efficiency. The integrated sensor cable enables accurate temperature monitoring and control of the solar pump unit. The system is available in two lengths—15m and 20m—to accommodate different installation requirements.

Technical parameters

The working temperature range of -40°C to +160°C allows the system to operate in a wide range of environmental conditions, including cold climates and high-temperature solar loops. The DN16 and DN20 pipe sizes are selected based on the flow rate and number of collectors in the system. The 13 mm EPDM HT insulation thickness provides effective thermal protection and reduces energy loss. The length options (15m and 20m) are chosen based on the distance between the collectors and the storage tank or pump unit.

Installation and connection

Installation of the HPW® TWIN system requires careful planning to ensure proper routing and connection. The flexible corrugated stainless steel pipes allow for easy bending around obstacles, but sharp bends should be avoided to prevent kinking. The system is supplied with brass fittings, high-temperature gaskets, and half-ring sets for secure connections. The 3/4" or 1" threaded brass fittings are used for DN16 and DN20 connections, respectively. A deformation screw is included for adjusting the fit during installation.

Before installation, check that the insulation is undamaged and that the sensor cable is intact. Ensure that the system is properly supported along its length to prevent sagging or mechanical stress. Common installation mistakes include using incorrect fittings, failing to support the pipe adequately, or neglecting to protect the insulation from physical damage. The system should be installed with a slight slope to allow for proper drainage and prevent water accumulation.

Compatibility and accessories

The HPW® TWIN system is compatible with solar collectors and storage tanks that use stainless steel or copper piping. It is suitable for use with solar pump units that require temperature signal transmission via a 2-core cable. The system is supplied with four brass fittings, four high-temperature gaskets, four half-ring sets, and one deformation screw. Additional accessories such as expansion joints or protective covers may be required depending on the installation environment.

For systems requiring expansion compensation, the Deformation Screw DN12 can be used in conjunction with the HPW® TWIN system. This accessory helps to absorb thermal expansion and reduce mechanical stress on the connections. When ordering, ensure that the correct number of fittings and accessories is included to match the number of connections required for the installation.

Technical background for designers

The HPW® TWIN system operates as a closed-loop solar thermal circuit, where the stainless steel corrugated pipes transport the heat transfer fluid between the solar collectors and the storage tank. The EPDM HT insulation minimises heat loss and ensures that the temperature differential between the collectors and the storage tank is maintained. The 2-core sensor cable allows for accurate temperature monitoring and control of the solar pump unit, ensuring optimal system performance.

The EPDM HT insulation is resistant to UV radiation and maintains its insulating properties over a wide temperature range. The system is designed for integration into solar thermal systems with operating temperatures up to 95°C and pressures up to 8 bar. The flexibility of the corrugated pipes allows for easy installation in complex layouts, reducing the need for additional fittings and joints.

Service and operation

Regular inspection of the HPW® TWIN system is recommended to ensure that the insulation remains intact and that the connections are secure. Check for signs of mechanical damage, such as kinks or abrasion, and ensure that the sensor cable is functioning correctly. The system does not require regular maintenance beyond visual inspection and cleaning of the connections. If the insulation becomes damaged, it should be replaced immediately to prevent heat loss and reduce system efficiency.

During operation, ensure that the system is properly drained during periods of non-use to prevent freezing and corrosion. The system should be checked for leaks and proper flow after installation and periodically thereafter. No specific service intervals are required for the HPW® TWIN system, but any signs of wear or damage should be addressed promptly to maintain system performance.

Frequently asked questions

Can the HPW® TWIN system be used with copper piping?
Yes, the HPW® TWIN system is compatible with copper piping as long as the connections are made using the appropriate fittings and gaskets. The brass fittings provided with the system are suitable for use with copper piping.

Is the sensor cable suitable for long-distance signal transmission?
The 2-core sensor cable is designed for use within the length of the HPW® TWIN system (15m or 20m). For longer distances, an external signal booster or extension cable may be required to maintain signal integrity.

Can the HPW® TWIN system be used in a closed-loop solar thermal system?
Yes, the HPW® TWIN system is designed for use in closed-loop solar thermal systems. The stainless steel corrugated pipes and EPDM HT insulation ensure that the system is suitable for transporting heat transfer fluid between the collectors and the storage tank.

What is the maximum operating pressure for the HPW® TWIN system?
The system is suitable for use at pressures up to 8 bar. Ensure that the system is installed and operated within these limits to maintain its integrity and performance.