The Role and Functioning of Microbubble Deaerators in Central Heating Systems

Microbubble deaerators also known as air separators are specialised devices used in central heating systems to remove the smallest air bubbles and circulating air, which can cause significant issues if not addressed. These devices are essential for maintaining the efficiency, performance, and longevity of heating systems. In this article, we will explore the working principles, applications, advantages, and types of microbubble deaerators, with a focus on their placement within central heating systems.

Working Principles of Deaerators

The fundamental principle behind microbubble deaerators is to create a large surface area for gases to escape from the liquid. This is achieved by breaking the liquid into tiny streams or droplets within a low-pressure environment inside the deaerator, which encourages dissolved gases to come out of solution and form microbubbles. These microbubbles are then released from the liquid, leaving it relatively free from dissolved gases. The deaerated liquid is collected and exits the chamber, ready for use in the system.

Deaerators in Central Heating Systems

Microbubble deaerators are typically installed at the hottest point of a central heating system, such as where the water leaves the boiler and enters the heating system. This is because the solubility of gases decreases with increasing temperature, making it an ideal location for the release of dissolved gases. The removal of air and microbubbles is crucial for preventing dirt formation and the negative effects on energy efficiency, failure sensitivity, and wear and tear of the system components.

Advantages of Microbubble Deaerators

The primary advantage of using microbubble deaerators is their ability to remove even the smallest air bubbles and circulating air, which automatic air vents and bleeding valves cannot achieve. This leads to a quieter system, less friction, and better heat transfer efficiency. Additionally, the prevention of air in the system reduces the formation of magnetic sludge, which can accumulate in various parts of the system and lead to blockages or breakdowns.

Types of Deaerators

Microbubble deaerators come in several types, such as those equipped with sheathing or stainless steel gauze, designed to facilitate the release of micro-air bubbles. Brands like IMI Zeparo, SpiroVent® and Flamcovent offer a range of designs and configurations tailored to diverse system needs. These deaerators are often fully serviceable, allowing for maintenance and ensuring prolonged usability. With bi-directional flow capabilities, they offer versatility in accommodating various system requirements and configurations. 

Placement in Central Heating Systems

In central heating systems, microbubble deaerators are strategically placed to maximise their effectiveness. As mentioned earlier, the hottest point of the system is the preferred location. However, it is important to consider the static head or pressure above the deaerator, as excessive pressure can prevent the release of dissolved air. If the static height is too great, a vacuum degasser might be a more effective solution.

Microbubble deaerators are essential components in central heating systems, designed to remove microbubbles and circulating air that can lead to inefficiencies and system damage. Their strategic placement at the hottest point of the system ensures optimal performance and contributes to the overall health and longevity of the heating system. With various types available, these deaerators can be tailored to meet the specific needs of different central heating systems, making them a versatile and valuable tool for maintaining system efficiency.