FEATURE AIR CONDITIONING Keeping cool on costs
operator can make the most of the capabilities of the BMS’ software and sensors. This alone can save huge amounts of energy, slashing energy costs by as much as 50 percent in many cases. Many of today’s drives include built-in
serial communications protocols. Several models will also offer a fieldbus adapter. This means the drive can connect to any BMS. Real-time clocks make it easy to schedule events, such as switching on air conditioning fan motors as the building fills up and turning them off at slack times. The timer allows the drive to act as a stand-alone control unit with no need for an input from the BMS. The clock can also be used to indicate the date of a fault, or to flag up that some inspection or maintenance is required. Modern drives often have numerous
HVAC specific macros such as supply fan, return fan and cooling tower, which can dramatically reduce set-up time. The panel can help users start up the drive, maintain it and diagnose faults. An on-board fault history assistant can
Carl Turbitt, Team Leader for HVAC Drives in the UK at ABB, discuses how air conditioning costs can be kept low by combining BMS and variable-speed drives into an energy management system
W
hen it comes to energy use league tables, buildings are near the top.
They are in fact the largest end-users of energy, responsible for 40 percent, well ahead of everyone’s favourite villain, vehicles. The potential for energy savings in buildings is high and set to increase still further, with global energy consumption for buildings expected to grow by 45 percent between 2002 and 2025. Much of this energy use of course goes
into maintaining an equitable temperature within buildings, making them comfortable places to be in. Managing energy use in air conditioning systems requires seamless control, which can be achieved by building management systems (BMS) combining both hardware and software. The hardware of a BMS typically consists of one or more control and processing units and some peripheral devices which control the operation of heating or cooling systems. The control unit runs the system based
on the information supplied by some of the peripherals or on pre-set instructions with commands sent from the central unit to the peripherals through
12 SPRING 2014 | ENERGY MANAGEMENT
communication cables. The software consists of the program and the instructions that allow the control unit to manage the operations of the peripheral devices and, through them, the appliances.
THE PERFECT MATCH One component that can help the BMS in its efforts to keep energy use in check is the variable-speed drive, or VSD. These provide infinite control over the speed of motors driving pumps and fans. Compared to cruder systems, such as
Omnibus building in Reigate is saving £20,000 a year on energy costs for the building’s HVAC system following the installation of ABB standard drives for HVAC
“Using
show the actual time when the fault occurred, speeding up drive repair. The assistant can detect, dirty filters and keep track of bearing and drive belt replacement intervals, as well as lubrication intervals for the driven equipment.
VSDs ensures that the BMS can achieve
maximum control over the building’s environment,
matching the temperature and humidity to the demands of the occupants ....."
direct-on-line and star delta starters, dampers and valves, which choke off the flow of air or liquid produced by a fan or pump, can be controlled more precisely through PID loops utilising the VSD’s control capabilities which can drive the fan or pump at the exact speed needed. Using VSDs ensures that the BMS can
achieve maximum control over the building’s environment, matching the temperature and humidity to the demands of the prevailing weather and number of occupants. In this way, the building
Carl Turbitt, Team Leader for HVAC Drives in the UK
MAJOR COST SAVINGS Many building operators are making dramatic savings by using VSDs to run their HVAC systems. Operators of the Omnibus building in Reigate, Surrey, are saving in the region of £20,000 a year on energy costs for the building’s HVAC system following the installation of ABB standard drives for HVAC. An energy appraisal by Econowise Drives and Controls revealed that the motors driving the system pumps were all running at full speed, with flow control achieved by
mechanical throttling. It was calculated that
putting VSDs on the application could save around £20,000 per annum in energy costs, with a
expected payback in under nine months. With better control, help with
maintenance and the ability to rein in rising energy bills, today’s VSDs, combined with BMS’, offer a complete energy management system to building operators.
ABB
www.abb.co.uk/energy 01925 741 111
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/ ENERGYMANAGEMENT
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