In our last article, we have shared why retrofitting old buildings is essential for our national commitment to sustainable development and some challenges facility managers and consultants may face when retrofitting an old building. 

So it is concluded that a well-planned retrofit approach can give old buildings a facelift and make them more sustainable and efficient. Now one may ask, how to map out plans for better efficiency and bigger savings?

Well, it is always advisable to start with (or at least give it a thought on) retrofitting the existing Air Conditioning and Mechanical Ventilation (ACMV) system, which can account for 60% energy consumption in a building [1].

But what is the most cost effective way to optimise the old equipment in ACMV system such as Air Handling Unit (AHU)? One solution is that you can simply retrofit or upgrade its essential parts instead of replacing the entire unit. As the critical component in ACMV system, fans can account for up to 35% energy consumption in ACMV systems [2]. For this reason, fan retrofit in ACMV systems is imperative and genuinely makes much difference in energy consumption. We are probably talking about 30 and 60% savings on annual electricity costs here.

In most of the old buildings, conventional AC belt-driven fans are deployed. These AC fans normally take up considerable amounts of space which makes installation rather complicated.  In addition, they also require ongoing maintenance and change of parts due to the number of wearing parts over the course of operation. The efficiency of AC fans is between 20% and 70% depending on the shaft power.

In contrast, EC fan powered by low carbon EC technology is increasingly recognised as being the best solution for energy efficient air movement.

EC standards for electronically commutated. EC fan, briefly speaking, refers to a fan powered by brushless, permanent magnet motor with electronic commutation. Its energy efficiency level can be as high as 90% meaning not only the better utilisation of energy, but also reduced heat loss and longer service life. In addition, EC fan’s motor and electronics are designed to perfectly fit one another. As such, additional electronic filters and shielded cables are unnecessary.

Besides the direct savings converting from AC to EC, each retrofit project should also consider the ease of installation as a metric for cost optimisation. In most cases, no specialised machinery is needed for the installation of EC fans as they are modular in structure, light in weight and easy to handle. Furthermore, EC fans are directly interchangeable with the AC fans, allowing for simple replacement with minimal disruption. Any voltage combination can be accommodated i.e. DC or AC single or three phase, as the electronics are fully integrated into the motor.

To summarise, upgrading from AC to EC fans is a simple and cost-effective retrofit solution for ACMV system. Nonetheless, our effort in exploring cutting-edge technologies for better air treatment does not stop here. In our next article, we will introduce our digital solutions that bring retrofit to the next level.