Existing air handling units often consume more energy than necessary. Targeted upgrades can significantly improve efficiency without complete unit replacement. Understanding upgrade options helps building operators reduce operating costs while extending equipment service life.
Fan System Upgrades
Fan assemblies often represent the best efficiency upgrade opportunities. Older fans with dated motor and impeller technology consume significantly more power than modern alternatives.
EC motor retrofits replace older AC motors with electronically commutated alternatives. Efficiency gains prove particularly significant at part-load operation typical of variable-demand systems.
Impeller upgrades using modern aerodynamic designs reduce pressure losses within fan assemblies. Backward-curved centrifugal fans generally outperform older paddle or forward-curved types.
Complete fan replacement with packaged EC plug fans simplifies retrofits while delivering substantial efficiency gains. Pre-assembled units reduce installation complexity.
Variable Speed Drive Retrofits
Adding VSDs to constant-speed fans enables capacity modulation through speed variation. The cubic relationship between speed and power consumption means modest speed reductions yield substantial energy savings.
VSD retrofits suit systems where actual demand varies but fixed-speed fans operate continuously at full capacity. Oversized systems particularly benefit from reduced speed operation.
Control integration connects VSDs to building management systems for coordinated operation. Pressure, temperature, or CO2 sensing can drive speed optimisation automatically.
Heat Recovery Additions
Units lacking heat recovery represent significant upgrade opportunities. Adding heat recovery captures exhaust air energy that current configurations waste entirely.
Retrofit heat recovery requires careful assessment of available space, air stream accessibility, and ductwork modifications. Some installations prove straightforward; others present significant challenges.
Plate heat exchangers suit many retrofit applications, offering good efficiency without moving parts complexity. Run-around coils enable recovery where streams cannot be brought together.
Payback periods for heat recovery additions often prove attractive, particularly in buildings with high ventilation rates and significant heating/cooling requirements.
Control System Upgrades
Modern controls optimise unit operation beyond older control technology capabilities. Upgrading controls unlocks efficiency improvements impossible with legacy systems.
Demand-controlled ventilation modulates fresh air based on actual occupancy rather than design assumptions. CO2 sensing provides proxy indication of occupancy for ventilation control.
Optimal start/stop algorithms minimise operating hours while ensuring buildings reach required conditions before occupancy. Learning algorithms improve timing based on building response.
Scheduled operation with holiday calendars prevents unnecessary operation during unoccupied periods. Simple measures but surprisingly often overlooked.
Coil Upgrades
Replacing heating and cooling coils can improve heat transfer efficiency. Modern coil designs may achieve required duties with lower water temperatures or smaller approach temperatures.
Coil cleaning improves efficiency without replacement. Contaminated coils require elevated temperatures to compensate for reduced heat transfer.
Adding coils for purposes like pre-heating or free cooling extends unit capabilities. Additional coil sections enable strategies not possible with original configurations.
Implementing Upgrades
Effective upgrades require thorough assessment of existing conditions and clear understanding of improvement targets. Ad-hoc upgrades without strategic planning may miss opportunities or waste investment.
Professional survey identifies upgrade opportunities and enables prioritisation. Some upgrades deliver better returns than others; assessment informs investment allocation.
Staged implementation can spread costs while progressively improving performance. Priority upgrades delivering best returns can proceed first, with lesser opportunities following.
I-Flow Technologies provides AHU upgrade services delivering measurable efficiency improvements. Our engineers assess opportunities, design solutions, and implement upgrades that reduce operating costs while extending equipment life. Contact us to discuss upgrade options for your air handling units.
