Air Handling Unit Refurbishment & Upgrade

Project Overview

At Phoenix Air Handling Ltd, we were engaged to deliver a full refurbishment and upgrade of two existing Air Handling Units, alongside the supply and installation of new extract systems. The project required a careful balance between improving performance and working within the constraints of existing plant.

From the outset, the focus was on bringing the existing systems up to modern performance standards while maintaining reliability and ease of maintenance.

Understanding the Existing System

Both units had reached a point where key components were no longer performing efficiently. The existing fan assemblies, filtration stages and coil arrangements were limiting airflow performance and energy efficiency.

Our approach was not simply to replace like for like, but to re-engineer the internal layout to improve overall system operation.

This included full strip-out of:

• Existing fan and motor assemblies

• Frost coils and associated pipework

• Filter sections and access arrangements

This created a clean starting point to rebuild the units with improved components and better airflow paths.

Refurbishment & Performance Improvements

The upgraded systems were designed to deliver improved efficiency and more stable control across both heating and cooling conditions.

New rigid bag filtration (F7 grade) was introduced to improve air quality while maintaining acceptable pressure drops.

A key part of the upgrade was the integration of run-around coil systems. These were designed to recover energy and stabilise air temperatures across seasonal conditions, delivering strong performance in both winter and summer operation. 

The systems were designed to handle:

• Low external temperatures while maintaining supply air conditions

• High summer loads with controlled humidity levels

• Efficient fluid circulation with optimised flow rates and pressure drops

This resulted in a more balanced and energy-conscious system overall.

Fan & Airflow Design

The fan upgrades were a critical element of the project.

New EC motor-driven fans were installed, selected to provide:

• Consistent airflow delivery

• Improved energy efficiency

• Reduced maintenance requirements

With airflow volumes ranging up to over 4 m³/s and external static pressures around 400 Pa, the systems were engineered to meet the demands of the building while maintaining reliable operation. 

Attention was also given to acoustic performance, ensuring the upgraded units remained suitable for their operating environment.

New Extract Air Handling Units

Alongside the refurbishment works, new extract Air Handling Units were supplied and installed.

These were constructed using:

• Aluminium framework with double skin panels

• Mineral wool insulation

• Weather-resistant external finishes

The units were designed for external installation and built to withstand operating conditions while maintaining thermal and acoustic performance.

Each unit included:

• High-efficiency EC fans

• Integrated filtration• Extract coil systems

• Weather louvre discharge

This ensured a fully matched system between supply and extract, improving overall system balance.

Flat Pack Delivery & Site Assembly

Due to site constraints, the units were supplied in flat pack form and assembled in position.

This allowed:

• Easier access into restricted plant areas

• Reduced lifting requirements

• Greater flexibility during installation

Our team managed offloading, positioning and full reassembly on site, ensuring the final installation met both design and practical requirements.

Delivering a Practical Solution

This project is a good example of how refurbishment, when done properly, can deliver results comparable to new installations.

Rather than replacing entire systems, we were able to:

• Extend the life of existing plant

• Improve efficiency and performance

• Introduce modern components and control capability

All while working within the physical limitations of the existing setup.

The Result

The upgraded systems now provide:

• Improved airflow and system stability

• Better energy performance through heat recovery

• Enhanced air quality through upgraded filtration

• More reliable and maintainable equipment

This project demonstrates Phoenix Air Handling’s ability to deliver bespoke, application-led air handling solutions, combining technical expertise with practical site awareness and strong project coordination.