For many years, engineering students at the University of Queensland have needed a facility to conduct HVAC experiments, Dr Saiied Aminossadati details the process.
The Newcrest HVAC laboratory will provide new opportunities for undergraduate and postgraduate students to test the application of fluid mechanics and heat transfer in various heating and cooling processes.
It is designed as a world-class facility to service multiple user groups covering areas such as indoor climate, energy economy and mechanical building services. It will help to keep the University of Queensland’s (UQ) graduates at the cutting-edge and ensure UQ remains at the forefront of engineering education.
The project would not have been possible without the generosity of Newcrest in providing $270,000 for this project.
The Newcrest HVAC Lab includes the following equipment: air conditioning unit, ventilation simulator unit, refrigeration laboratory unit, linear heat conduction unit and a temperature measurement unit.
Air conditioning unit
This is a complete, upgradeable, instrumented air conditioning laboratory unit mounted on a steel frame and castor wheels.
The unit provides the opportunity for students interested in careers involved in
the design, operation and servicing of air conditioning plant to be completely familiar with the processes occurring between air inlet and its discharge to the conditioned space.
Its capabilities include the ability to: demonstrate the processes and components used in heating, cooling, humidification, dehumidification of an airstream; measure the psychrometric condition of air before and after humidification, heating, dehumidification/cooling using pairs of precision wet and dry bulb sensors; determine a heat and mass balance across each process; construct a complete refrigeration cycle diagram; investigate the volumetric efficiency of the refrigeration compressor under varying load; determine the specific heat capacity of air, by measurement of the change in psychrometric condition across a heating or cooling process.
Ventilation simulator unit
This is a realistically scaled ventilation training unit capable of enabling students to study basic airflow and fluid mechanics as well as the more complex process of commissioning and balancing a multi ducted air distribution system.
The unit consists of a forward curved variable speed centrifugal fan and integral control console. The fan has a supply pressure of up to 350 Newtons per square metre and a flow rate of approximately 1400 cubic metres per hour depending upon the blockage factor.
Its capabilities include examination of typical components, fabrication, installation and assembly techniques used in air handling systems; investigation of pressure losses in bends, branches, changes of section and over straight lengths of duct; determination of ‘K’ factor for a pressure loss; investigation of the fan pressure and volume flow characteristics at various supply voltages; measurement of airflow rate using Pitot-static tube, orifice plate and anemometer methods; balancing of airflow distribution in a series or two (three) branch parallel distribution system.
Refrigeration laboratory unit
This is a fully instrumented refrigerant R134a vapour compression refrigerator with belt driven compressor, electrically heated evaporator, thermostatic expansion valve and water cooled condenser.
Operating parameters can be varied by adjustment of condenser cooling water flow and electrically heated evaporator supply voltage.
This unit can: produce a vapour compression cycle diagram under various conditions; produce an energy balance for the refrigerator; investigate the variation in refrigerator duty or cooling ability for various condensing temperatures; investigate the variation in refrigeration coefficient of performance for the various condensing temperatures; investigate power input based on electrical, shaft and indicated power.
Linear heat conduction unit
This unit is a small-scale accessory that allows experimental investigation of linear heat conduction and the measurement of the thermal conductivity of various solid conductors and insulators.
This unit will provide: understanding of the Fourier rate equation in determining the rate of heat flow through solid materials; measuring the temperature distribution for steady state conduction of energy through a uniform state condition of energy through a uniform plane solid and a composite plane solid; determine the constant of proportionality (thermal conductivity) of different materials; measuring the temperature drop at the contact face between adjacent layers in a composite plane solid; measuring the temperature distribution for steady state conduction of energy through plane solid of reduced cross sectional area.
Temperature measurement unit
This unit allows students to thoroughly examine a large variety of temperature measurement devices, how errors can be introduced and avoided, methods of calibration and the structure of the International Temperature scale.
Its capabilities include: the use of (expansion) liquid in glass thermometers
for measurement of fixed scale points; the use of vapour pressure for temperature measurement; the use of bi-metallic expansion devices for temperature measurement; the Peltier and Seebeck thermo-electric effects; investigation of junction voltage from different thermocouple types; the use of ice point reference with a thermocouple; the law of intermediate metals and intermediate temperatures associated with thermocouples; voltage calibration of different thermocouple types using a water-ice reference; connection of thermocouples in series for signal amplification and parallel for averaging of measured temperatures.