Summary of Contents for Armfield RA2
- Page 1 An ISO 9001 Company INSTRUCTION MANUAL ISSUE 2 September 2009 Air Conditioning Unit RA2...
- Page 3 Supervision of users should be provided whenever appropriate. Your Air Conditioning Unit RA2 has been designed to be safe in use when installed, operated and maintained in accordance with the instructions in this manual. As with any piece of sophisticated equipment, dangers may exist if the equipment is misused, mishandled or badly maintained.
- Page 4 RA2 Air Conditioning • When lifting is required, two or more people will be required for safety. All should be made aware of safe lifting techniques to avoid strained backs, crushed toes, and similar injuries. • Safety shoes and/or gloves should be worn as appropriate.
- Page 5 RA2 Air Conditioning • Long hair should be tied back out of the way and dangling items such as necklaces, scarves or neckties should be removed or secured so that they cannot become entangled in the equipment. • Do not touch or insert any object into any moving component while the apparatus is in use.
- Page 6 CFC (chloro-fluoro-carbon) refrigerants such as R-12. R134a is colourless, nonflammable and noncorrosive with a very faint odour. In the RA2 it is contained within a completely sealed unit, and is safe under normal use as described in this manual.
- Page 7 RA2 Air Conditioning In the event of damage to the refrigeration unit, the unit must only be repaired or replaced by a suitably qualified engineer. Contact Armfield or your local agent for advice.
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Page 8: Table Of Contents
RA2 Air Conditioning AIR CONDITIONING UNIT Contents Introduction to the Equipment ......................... 8 Diagram 1: Front View of Apparatus ......................9 Diagram 2: Top View of Apparatus......................10 Description ............................... 11 Overview ..............................11 Control Box.............................. 11 Axial Fan..............................12 Pre-heater and Re-heater ........................ - Page 9 RA2 Air Conditioning General..............................26 RCD Test ..............................26 Calibration of Relative Humidity Sensors ....................26 Calibration of Temperature and Air Flow Sensors ..................27 Cleaning Procedure ..........................27 Background and Theory..........................30 Background ..............................30 Nomenclature ............................31 Psychrometric chart and Glossary ......................32 Using Calculations instead of the Psychrometric Chart to Determine the Air State........34 Other Calculations Required........................38...
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Page 10: Introduction To The Equipment
Air Conditioning processes: cooling, heating, humidifying and dehumidifying. The effect and relationships of the primary processes involved in air handling systems can be investigated. The RA2 Unit is designed so that the student can simulate different environments and perform measurements to allow psychrometric data analysis. -
Page 11: Diagram 1: Front View Of Apparatus
Evaporator Pre-heaters Re-heaters Louver RH/T RH/T Boiler Air velocity assembly sensor sensor assembly outlet sensor RH/T sensor RH/T sensor LH duct assembly RH duct assembly... -
Page 12: Diagram 2: Top View Of Apparatus
RH/T RH/T Air velocity Louver RH/T sensor sensor sensor assembly Pre-heaters Evaporator sensor RH/T Fan assembly Steam lance Re-heaters sensor LH duct assembly RH duct assembly... -
Page 13: Description
Where necessary, refer to the drawings on pages 9 and 10. Overview The RA2 is a bench-top unit which comprises of a square ventilation duct mounted on a mild steel support frame. The duct is made of clear acrylic so all components are clearly visible: air fan, air preheater, humidifier tube, chiller/dehumidifier heat exchanger and air reheater. -
Page 14: Axial Fan
RA2 Air Conditioning Axial Fan The axial fan moves the air through the duct. The speed of the fan may be controlled to give different air flow rates. The fan must be on when both the pre- heater and re-heater are on to avoid heat damage to the acrylic duct during operation. -
Page 15: Evaporator
RA2 Air Conditioning Evaporator The refrigerating capacity of approximately 500W at 20°C is generated by an evaporator, which is part of a compact refrigeration system. The refrigeration unit is used to cool and dehumidify the air stream. The evaporator consists of a direct- expansion coil operated with a thermostatic expansion valve. -
Page 16: Condensing Unit
RA2 Air Conditioning Condensing Unit The Condensing Unit, located below the ventilation duct, incorporates a compressor and a condenser. The compressor is used to compress gaseous refrigerant leaving the evaporator, and in the fan cooled condenser the refrigerant gives away the heat gained in the evaporator. -
Page 17: Humidifier
If this occurs, wait 2 minutes and refill boiler, the cut off will self reset and steam can be produced again with 5 -12 minutes. Power to the boiler heaters can be remotely controlled and monitored using the Armfield RA2 Software. -
Page 18: Air Velocity Sensor
RA2 Air Conditioning Air Velocity Sensor The air velocity in the duct is measured by the air velocity transmitter. This operates on the hot film anemometer principle, using special thin film. It has very good accuracy at low air velocities. The working range is 0–10m/s and the response time can be up to 4 seconds at constant temperature. -
Page 19: Temperature / Relative Humidity Sensor
Routine Maintenance section. 2.10 Data Logger/Equipment Controller and Software The Armfield RA2 Air Conditioning Unit is designed to be operated using the RA2-304 software supplied with the equipment. The RA2 Air Conditioning Unit must therefore be connected to a suitable PC running the RA2-304 software (or an equivalent program created by the student). -
Page 20: Operation And Software
Help texts provided with the Software Check that the USB connection is made between the RA2 unit and the PC, and that the RA2 software is installed and running. Check that the circuit breakers and RCD device at the rear of the unit are in the on (up) position.
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