HVAC manufacturers around the world are constantly developing new enthalpy wheels. These energy recovery devices have proven incredibly successful thanks to their performance capabilities. As a result, enthalpy wheels are now common in both new buildings and retrofits. Enthalpy wheels – or energy recovery wheels (ERWs) – are among the world’s most effective technologies for recovering both sensible (heat) and latent (moisture) energy. They deliver a range of benefits to building owners and operators, including significant energy savings and thus lower energy costs. Within three years, for example, the savings generated by a modern enthalpy wheel can cover the initial expenditure needed for its purchase and installation.
ERWs operate on a simple engineering principle. They transfer energy from exhaust (outgoing) air into incoming (outdoor) air. Incoming and exhaust airflows run adjacent to each other, with an enthalpy wheel turning across both airflows. The wheel captures heat and humidity from the exhaust air, then transfers it into the incoming air. This reduces the need for an HVAC system to consume the energy it would otherwise need to independently regulate indoor temperature and humidity levels. By recycling energy, enthalpy wheels are considered an environmentally friendly, green HVAC solution. See our extensive guide for full details on how an enthalpy wheel works.
Factors affecting the performance of an enthalpy wheel
Modern ERWs are finely-tuned pieces of engineering. Even the smallest changes can have a large impact on the performance of an enthalpy wheel. In general, however, four main factors tend to influence their final efficiency. It is important to understand these factors when trying to balance energy efficiency and indoor air quality.
- The type of porous surface used to capture sensible and latent energy can dramatically impact overall performance. Desiccant coatings, such as molecular 3A sieves, are popular choices for ERWs and are proven to be highly effective.
- The percentage of the effective area of the wheel directly affects how much energy can be transferred from one airflow to another. To get maximum results, look for enthalpy wheels with smaller casing and – ideally – a single-structure construction (without segments).
- Air leakage, which can be a significant issue. If an ERW is poorly designed, it is unlikely to deliver optimal performance. Check for details of the sealing system used in your chosen enthalpy wheel.
- The efficiency and reliability of the drive system is also something that demands close attention. If cheap components are used, the likelihood of failure increases in parts such as the belt, motor, gearing or bearings. Even degradations, rather than outright component failure, can negatively affect how well an enthalpy wheel performs.
The world’s leading enthalpy wheel manufacturers
Who are the leading suppliers of ERW? Below, you will find a list of seven HVAC manufacturers. Each has their own area of expertise and specific reputational strengths.
- HEATEX offers five different models of enthalpy wheel. Three of them have no segments, and its rotor diameters range from a relatively small 200mm up to 3800mm. Founded in Sweden in the 1960s, it launched a North American operation in 2004 and a Chinese business in 2005.
- HOVAL has been in operation for almost 100 years. Its founder, Gustav Ospelt, first established the company in Vaduz, Liechtenstein. Today the company operates in more than 50 countries and offers three different energy recovery wheels. HOVAL solutions focus on transferring humidity and use a 3A molecular sieve coating.
- Systemair is a Swedish HVAC manufacturer that offers a range of ERWs for residential settings. Its enthalpy wheels are available in false ceiling, top connected and side connected units. Systemair models also include EC fans.
- DRI – or Desiccant Rotors International, to give it its full name – is headquartered in India. The company exports its enthalpy wheels to South East Asia, China, West Asia, Africa, Australia, Japan, Korea, Europe and North America. Its EcoFresh Energy Recovery Wheel recovers both sensible and latent energy and uses a 3A molecular sieve coating.
- ERI Corporation focuses on innovation and progress. The company produces enthalpy wheels that are frost resistant from -15°C, with airflows of up to 150,000 m3/h. ERI Corporation ERWs offer a maximum efficiency of 85%, include an antibacterial treatment, and are available in widths of 200mm, 250mm and 400mm.
- Klingenburg was founded in Germany in 1979. It has since spread to Poland, Spain, USA and the United Kingdom. It claims to design the world’s largest enthalpy wheels (eight metres in diameter) and its ERWs achieve efficiency levels of up to 85%. Moreover, Klingenburg delivers bespoke units, with a rotor measured to the nearest millimetre.
- Swiss Rotors is a world leader in the HVAC industry, using artificial intelligence, automation and robotics in its design and manufacturing processes. We aim to drive down costs and human error production mistakes while increasing customer satisfaction and product reliability. Swiss Rotors produces more than 65,000 enthalpy wheels each year, ensuring Swiss quality runs through all of its range. Swiss Rotors is determined to deliver energy saving solutions to the world, because it believes this a key way of ensuring the future of our green planet. It aims to educate and raise public awareness about the depletion of the world’s natural resources; to create revolutionary energy recovery solutions in the HVAC industry; and to optimize production processes for client and environmental benefits.
Advantages of the Swiss Rotors enthalpy wheels
Swiss Rotors’ design expertise is perfectly encapsulated in its range of enthalpy wheels offered in 18 standard casing sizes. At 87% energy recovery efficiency, it leads the industry in terms of green performance. A combination of intelligent design choices have made our ERWs renowned across the HVAC industry. A fast-acting 3A molecular sieve desiccant coating captures and releases both sensible and latent energy, while antimicrobial protection helps to guarantee ongoing excellence in performance and hygiene.
In recognising the importance of design, Swiss Rotors’ engineers have created a single patented continuous manufacturing process for its aluminum wheel and the application of the desiccant coating. By creating a single structure, rather than relying on traditional segments, we reduced the weight of each enthalpy wheel and increased the overall effective area of the wheel by up to 8% compared to competitive solutions. At the same time, a double sealing system minimises air leakage and increases overall effectiveness by a further 2%.
Clever design runs throughout the Swiss Rotors ERW. An optional purge device can be included to eliminate cross-contamination between air streams. A Fenner PowerTwist belt, which is used in all models, has been specifically designed to maintain belt tension – thanks to this, repairs and associated labour costs are significantly lowered.
Swiss Rotors clients can take advantage of the EC motor and the integrated variable frequency drive to precisely control the performance and efficiency of their energy recovery wheel. Other elements, such as the double-wall casing, extruded aluminium wheel hubs and the permanently lubricated 200,000-hour (L50) bearings, also guarantee enduring excellence.
Swiss Rotors enthalpy wheels are manufactured in the USA, UAE and Europe, and available in 4”/100 mm (SF Series) and 8”/200 mm (RT Series) widths, making them ideal for retrofits as well as new buildings. The SF Series ranges from 21” to 83” / 500 mm to 2400 mm in diameter; the RT Series covers 21” to 92”/ 500 mm to 2400 mm diameters. Every model is AHRI 1060 certified. The Swiss Rotors enthalpy wheel is a true measure of excellence, with market-leading energy recovery efficiency levels and world-class components and design. View the full range of Swiss Rotors products to find out more about how our solutions can help you achieve significant cost and environmental savings.