JJosé Antonio Torre (ATECYR): AHUs satisfy the requirements for air quality, ventilation and climatisation

What are Air Handling Units (AHUs)?

These are climatisation systems bespoke designed to satisfy a building’s requirements for air quality, ventilation and climate control, in accordance with its intended use and typology. 

What roles do they perform?

They perform a diverse range of processes, including ventilation, filtration, energy recovery, free cooling, heating/cooling and humidity control, as well as managing pressure differentials and airflows between the various areas of the building to prevent contaminated air from entering clean zones. 

What kind of buildings or facilities are they intended for?

Generally, buildings with centralised climatisation systems, such as hospitals, schools, office buildings, hotels, care homes, sports centres, laboratories, shopping centres or industrial facilities, although they can sometimes also be found in smaller premises.

Why does the design of equipment vary depending on its intended use and application?

Depending on the usage and application of a building, requirements regarding air quality, filtration, temperature, humidity and even acoustics can vary considerably; consequently, the AHU must be designed to incorporate specialised components.

For example, hospitals require extremely high standards of hygiene, as well as airflow control measures to prevent contamination from entering operating theatres. This will determine how the AHU is configured, ensuring not only that all these processes can be performed on the air to meet the required thermal, hygrometric and air quality standards, but also that maintenance and disinfection of the equipment itself can be executed.

An air-handling unit for an auditorium or cinema, however, even without having to meet such stringent hygiene standards, must still ensure proper ventilation, comfort and a very low noise level that does not detract from the performance. 

What innovations does the Technical Document for Building Installations (DTIE 9.10) introduce regarding calculation and design?

Previously, there was no DTIE specifically dedicated to the calculation and design of air handling units (AHUs). The opening chapters outline and explain the context and functions of air handling units within a building, along with the performance characteristics and requirements to be satisfied. The remaining chapters cover every process carried out within the AHU, examining the relevant components for each case and the criteria for their calculation and sizing under the current regulatory framework.

At the end of the document, a complete calculation example for an AHU is provided, starting with the building’s load calculations and proceeding to the sizing and selection of every AHU component to optimise performance, efficiency and technical specifications.

In what way does this DTIE affect the work of designers, engineers, technicians and other professionals in the sector?

The DTIE is designed to serve as a reference guide for both design engineers, technicians and professionals accustomed to working with AHUs who want to explore specific aspects in more depth, and for technicians working on climatisation systems who wish to broaden their knowledge of AHUs and gain a comprehensive overview. Throughout the document, many of the issues that professionals encounter in their daily work are addressed in a thorough and comprehensive manner.

Are there any other aspects you find noteworthy about this technical document?

The overarching aim has been to provide practical guidance throughout. For this reason, the document provides practical solutions to real-world scenarios that technicians and designers encounter when tasked with designing an AHU. Similarly, it contains numerous illustrative examples that are highly beneficial.