The transfer circuit lines transport the heat transfer fluid between the panel field and the elements of the solar circuit in the technical room.
Once the inter-panel links are installed on the panels, the transfer lines are to be connected to the male inlet/ outlet M3/4'' fittings for DN15 links, or M1'' fittings for DN26 links, installed at the end of the DualQuickfit inter-panel links.
The sealing of the fittings is ensured by a high-temperature fibre O-seal (in addition to the usual sealing products such as oakum, filetix, etc.).
The choice of transfer lines must be considered in order to:
- optimize ease and cost of installation
- limit linear pressure losses
Indeed, the flow rate of the heat transfer fluid passing through the transfer lines is a function of the number of panels. This determines the diameter of the pipes to limit the linear pressure losses. The choice of pipe diameter can change the choice of pipe material according to technical and economic criteria.
Selection of transfer lines - Pressurized system
For the connection of the solar station to the fields of panels, three types of pipes can be used:
- Copper pipes
- Stainless steel pipes
- PEX-Al-PEX multilayer pipes
It is possible to choose transfer pipes in multilayer PEX-Al-PEX due to the limited temperatures (<80°C) and pressures (<<6 bar) in the solar circuit with DualSun SPRING hybrid solar panels.
- The hydraulic circuit must be designed taking into account the rate of thermal expansion of the pipes
- The hydraulic lines must resist UV rays, corrosion due to external agents and wildlife (rodents, birds) for parts exposed to the outdoors
- Hydraulic lines and fittings must be of compatible materials
Burrying of the multilayer pipe
be aware that it is necessary to protect the tube when it is buried underground with a sleeve or sheath of the type “TPC” (Cable Protection Tube). This sheath must withstand crushing and be waterproof over its entire length.
The insulation of the pre-insulated tube is not designed to withstand moisture, so if there is a risk of contact with water, it is preferable to use insulators specifically built for this purpose.
Selection of transfer pipes for DualSun solar swimming pool heating system
For direct swimming pool heating systems, it is recommended to use pressure PVC pipes with anti UV treatment.
For aesthetic reasons, it is possible to paint PVC pipes: take a good quality paint, anti UV if possible.
>To go further : What are the components of the kit for pressurized systems?