This webinar is presented by Richard Zhang from Swegon and focuses on energy recovery in low ambient environments, particularly in commercial ventilation systems. The session emphasizes the importance of frost prevention in energy recovery units (ERVs) and how Swegon’s innovative technologies address these challenges effectively.
Richard begins by discussing the common issue of frost formation in energy recovery ventilators operating in cold climates. Traditional systems rely on default frost control strategies that can prematurely activate, leading to energy loss. To improve this, Swegon focuses on a strategy that considers three factors: outdoor air temperature, latent efficiency, and indoor relative humidity. These factors collectively determine how effectively an ERV can prevent frost formation.
One key point Richard highlights is the role of latent efficiency, certified by AHRI 1060 standards. In extreme cases, where the latent efficiency is low (close to zero), frost forms on the heat exchanger at temperatures as high as 32°F, requiring immediate activation of frost control measures. In contrast, higher latent efficiency systems (closer to 100%) can operate without frost formation at much lower temperatures. Swegon’s energy recovery systems feature higher latent efficiency, allowing them to function efficiently at temperatures as low as -10°F without frost formation.
Another crucial factor in frost prevention is indoor relative humidity. Richard explains that higher indoor humidity levels increase the likelihood of frost formation on the heat exchanger. For example, in environments with 30% relative humidity, frost forms at higher outdoor temperatures. However, in drier environments, such as those with 10% relative humidity, frost is much less likely to form, even at extremely low temperatures.
Swegon’s high-efficiency rotors are designed to handle these conditions by significantly improving energy recovery while minimizing the need for frost control. By using a high-latent-efficiency rotor, Swegon’s systems can operate at temperatures down to -10°F without frost. In extreme conditions, when frost control is necessary, Swegon uses a pressure-sensor-based strategy to precisely monitor frost buildup and activate defrosting only when absolutely needed. This method is more energy-efficient compared to traditional strategies that rely solely on outdoor air temperature monitoring.
Richard also discusses Swegon’s unique defrost control mechanism, which involves gradually slowing down the rotor to as low as 0.5 RPM. This slow rotation allows the system to maintain energy recovery while defrosting, avoiding the need for external preheating and significantly reducing energy consumption.
In conclusion, Swegon’s advanced energy recovery systems provide an effective solution for maintaining efficiency and preventing frost formation in low ambient environments. By focusing on latent efficiency, indoor humidity, and precise defrost control, these systems offer superior performance and reduced energy consumption, making them ideal for use in cold climates like Denver, Colorado.
