A climate control system supplied by Greenville IDC at Belfast International Airport has led to annual savings of £112,000 per year. Not only this, but also a reduction of 500 tonnes of carbon emissions. The installation of energy- efficient VLT® drives has improved air quality for 5 million passengers each year and turned the airport into a greener facility.
Following the previous success of retrofitting VSDs to two 30 kW circulating pump drives, Airport Technical Supervisor Colin Sloan decided to fit variable speed drive control to the 28 fans on the AHUs covering 35–40% of the main airport.
“From past experience, we knew that VSDs could offer substantial energy savings and with rapidly rising electricity prices. As well as, prompting the availability of a 30% grant from our energy supplier, Energia. Under their Energy Efficiency Scheme, we decided to refurbish a number of our air handling units with variable speed drive control.”
Demand matched Speed Control
Belfast International Airport handles over 5,000,000 passengers per year. The air conditioning system is in operation continuously to guarantee passenger comfort. Some 28 fans, totalling 240 kW of installed load, represent a significant proportion of the airport’s annual energy bill.
Previously, the fans were running uncontrolled at full speed with direct on-line start. Preliminary measurements had indicated that the motors were oversized. As well as, running inefficiently and well below full capacity. Fitting VLT® drives would not only offer energy savings but would improve passenger comfort throughout the airport.
Carried out a Site Survey
VIS Security Solutions carried out a detailed site survey of existing loads and presented a report which showed that with only a 20% turn down on fan speed. Therefore, the system would return energy saving sufficient to pay for itself in less than 1 year. The survey highlighted, that conditions within the airport, varying widely with daily and seasonal temperature conditions and passenger numbers. This could be stabilised by linking the drives through ModBus & BACnet communications with CO2 monitors, which measure the energy savings in each of the passenger processing areas.
Great savings with VLT® Control
In addition to this, 28 Danfoss VLT® 6000 HVAC drives, supplied by ourselves, Greenville IDC an official Danfoss Partner. These were installed and commissioned, initially with the drive outputs limited to 30 – 37Hz, pending full commissioning of the air quality monitors. Despite the hot summer conditions, during which the air-con system functioned satisfactorily with the fans at 80% speed. The actual savings exceeded expectations and the energy bill was down by over £16,800 for the three month period. In cooler weather conditions, it is anticipated that savings will be even greater. Especially with the AHUs under full automatic environmental control.
Return on Investment
According to Colin Sloan, “the return on energy saving is so good that the investment has paid for itself in less than one year. Comfort conditions for our customers have definitely improved,” says Colin Sloan. “It was vital that there was minimal disruption to the airport during the refurbishment. VIS Security Solutions took every opportunity to simplify the installation process. The use of field-bus communication reduced the complexity and cost of the control wiring. Moreover, the new control panels were pre-built and installed with the existing control panels used temporarily as a junction box.”
All of the work was carried out during normal working hours but nonetheless, downtime was absolutely minimal during the change-over. Neither the staff nor the passengers noticed any disruption.
More savings to come
Thanks to this success, the airport management is currently looking at the remainder of the air-handling units and every variable load device across the airport. This is with a view to fitting variable speed drives to them and making even greater savings. Better air quality is being delivered to the passengers and at the same time the airport saves 1 million kWh. As well as, saving a lot of money every year through the installation of variable speed drives. “Due to rising electricity prices, the savings are now £112,000 per annum. It’s much more than the £67,000 we had estimated.” Colin Sloan, technical supervisor at Belfast International Airport, says. The installation of VLT® drives have turned the airport into a greener facility. This results in considerable energy savings and reductions in carbon emissions.