The environmental benefits of mechanical ventilation have long been clear - but in Mechanical Ventilation with Heat Recovery (MVHR), it’s possible to take the sustainable approach one step further. Rupert Kazlauciunas, technical product manager, MVHR, Zehnder Group UK, explains.
Heat recovery ventilation offers the optimal solution for energy performance, as well as providing excellent air quality in the building throughout the year.
It’s also possible to use recyclable materials throughout the manufacturing process, in order to produce optimal performance and durable ventilation solutions. For example, the ductwork that carries the air throughout the house can be made from pure food grade polyethylene which is 100 per cent recyclable. Making units easy to disassemble when they reach their end of life is another key way to ensure sustainability, so that recyclable materials are simple to separate.
Material that is easily recyclable
The majority of components and parts can actually be made from fully or partly recyclable materials, even plastics.
To make recycling simpler, plastic parts of MVHR units can be marked with a material code to aid immediate identification. Sustainable units can be made using expanded polypropylene, a recyclable closed-cell moulded foam.
Hard-plastic components can be made from Acrylonitrile Butadiene Styrene (ABS), an opaque thermoplastic that, unlike thermosets, can be easily recycled. Foam parts can be manufactured with low-density polyethylene (LDPE), which can enjoy a second life as a shipping envelope, bin liner, floor tile, furniture or, perhaps even in next-generation ventilation units.
Polycarbonate is an incredibly strong material that is often used, for example, for bus stops. It is fully recyclable and the natural oil that is used to create it produces one of the best yields for plastic recycling facilities. In MVHR units, it can be used to make the transparent parts.
Smaller MVHR components, such as the drive train valve, are often created using Polyoxymethylene (POM), an engineering thermoplastic. Thermoplastics are widely recycled and POM is typically used for precision parts requiring high stiffness, low friction and excellent dimensional stability.
Recyclable at specialist centres
The materials should be, where possible, sourced locally and need to be transported less than 600 miles to save on carbon footprint and spare parts should be kept in stock for a minimum of ten years – even if the model has been discontinued.
Using fully recyclable materials is always preferable, but for parts where this isn’t yet a viable option, it’s possible to use those that can be recycled but only at specialist centres. Electronic components, potted sensors, cables and PCBs (printed circuit boards) must be made from mixed materials and this can only be separated for recycling at specialist centres.
Similarly, the materials used to form heat exchangers is a mix of polystyrene (for the sheets) and hard polystyrene (for the casing). These need to be combined and sealed with glue, which makes recycling harder to achieve.
Sustainability is about more than just energy efficiency
The benefits of MVHR in returning heat to the house and ensuring a healthier indoor environment are clear, but there are other ways that the industry can become more responsible in ensuring a sustainable future. Using eco-friendly and recyclable materials where possible, as well as selecting and working with sustainability-focused partners and suppliers, can all make a difference in the fight for a more environmentally-focused future.
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