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Recirculating Air Conditioning Unit

The floor standing RA3 Recirculating Air Conditioning Unit features all the facilities of the RA2, plus adjustable recirculation of air, additional sensors, and a recirculation facility via an enclosed climate control chamber.

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RA3

REFRIGERATION & AIR CONDITIONING
RA2 Air Conditioning Unit
RA3 Recirculating Air Conditioning Unit - Issue 1

RA2 is a fully instrumented bench mounted air conditioning duct for teaching all aspects of air conditioning systems.

RA3 is a floor standing unit, with all the facilities of RA2 plus a recirculation facility via an enclosed chamber. Some of the air exiting the chamber can be recycled back into the conditioning duct.

Ordering Specification

RA2

• Air Conditioning teaching system, complete with initial heating stage, humidifier, chiller/dehumidifier and final heating stage
• Transparent duct (200mm x 200 mm) for complete visibility of the process
• Computer controlled via USB interface, with complete educational software including data logging, graph plotting with real time updates, mimic diagrams, data export
• Educational software, replicating the psychrometric chart calculations
• 4 sets of Temperature and Relative Humidity measurements at the various stages of the process
• RH sensors come with calibration values which can be entered into the software for best accuracy
• Electronic Flowmeter to measure the air flow in the duct
• Dual control of boiler setting with a fast heat up setting and a gentle setting for control

RA3

• Comprehensive Air Conditioning teaching system, complete with initial heating stage, humidifier, chiller/dehumidifier, final heating stage, climatic chamber with window, return duct and adjustable recirculation
• Transparent conditioning duct (200mm x 200 mm) for complete visibility of the process
• Computer controlled via USB interface, with complete educational software including data logging, graph plotting with real time updates, mimic diagrams, data export
• Educational software, replicating the psychrometric chart calculations
• Six sets of Temperature and Relative Humidity measurements at the various stages of the process
• RH sensors come with calibration values which can be entered into the software for best accuracy
• Electronic flowmeters (2) measure the flow in each duct
• Measurement of refrigerant pressures, temperatures and flow
• Dual control of boiler setting with a fast heat up setting and a gentle setting for control

Features

> Transparent Duct for full visibility of the process and the components
> Includes pre-heaters, humidifier, chiller/dehumidifier and reheaters
> Fully instrumented, with temperature and Relative Humidity sensors at every stage of the process, plus an air flow sensor.
> RH sensors calibrated for maximum accuracy.
> Suitable for both vocational training and for rigorous academic analysis of the thermodynamic principles involved
> Fully computer controlled with real time data logging of results (requires a pc not supplied by Armfield)
> Capability of using PID control for preheat, humidity and reheat allows stable conditions to be set up for investigations

Additional Features with RA3

> Enclosed climate control chamber
> Adjustable recirculation of air leaving the chamber back into the conditioning duct
> Additional sensors, including refrigerant pressures and flow

Demonstration Capabilities

> Understanding and using psychrometric charts, Relative Humidity and Humidity ratios
> Sensible Heating and Cooling of air
> Humidification and Dehumidification
> Understanding Enthalpy

Additional Instructional Capability with RA3
> Energy savings with recirculation
> Heat transfer across the evaporator

Description

The RA2 duct is fabricated from clear acrylic for visibility and mounted on a painted steel frame.

Air is drawn into the duct by a variable speed fan, and is passed through a flow straightener to the preheat heating elements. The air is then passed over a nozzle from a steam boiler, which allows the air to be humidified.

The next component in the duct is the evaporator of the integral refrigeration unit. As the air passes through the evaporator it is cooled down. The evaporator housing also allows any water which condenses from the air to be collected in an external vessel.

After the evaporator the air passes over the reheat elements and out through a louvered exit.

Temperature and RH sensors are provided at the air inlet, after the preheat and humidifier, after the evaporator and after the reheat. The air flow is measured by an electronic sensor. The mains supply voltage is monitored in the equipment to allow calculation of effective heater powers

Underneath the duct are mounted the steam boiler for the humidifier, the compressor and condenser for the refrigeration system and the electronic control box.

On RA3 the air out of the duct is passed into a chamber to demonstrate climate control. The exit duct from the chamber is fitted with adjustable vents allowing some of the air to be recirculated back to the duct inlet. Additional sensors measure the temperature and RH at the chamber outlet and after the recirculated air is mixed with the inlet air. Also the flow rate of the recirculated air.

The RA3 also includes pressure gauges and temperature sensors to allow the refrigerant temperature change across the condenser and evaporator to be established. The refrigerant flow rate is also measured using a variable area flowmeter.

Software Details

The RA2 and RA3 are controlled from a personal computer (not supplied) using a USB interface. Powerful software is supplied with detailed mimic diagrams, and full instructional help texts, comprehensive data logging and graph plotting facilities, together with sensor calibrations and a wide variety of display and data export options.

For more details of the capability of the Armfield software visit: www.discoverarmfield.co.uk/data/armsoft

Technical Details

Item Value
Duct Size 200mm x 200mm
Air speed variable to > 1m/s
Preheaters 400W
Final Heaters 200W
Refrigerant R134a
Boiler Power 2KW nominal
Chiller Power 500W nominal
Chamber Volume (RA3) 230 litre

Complementary Products

RA1 Vapour-Compression Refrigeration Unit
TH1 Temperature Measurement and Calibration
TH2 Pressure Measurement and Calibration
TH3 Saturation Pressure
TH4 Recycle Loops
TH5 Expansion Processes of a Perfect Gas

Ordering Details

RA2-A/B/G
RA3-A/B/G

Essential Accessories

Personal Computer (PC), running Windows XP or above, with spare USB port (not supplied).

Requirements/order Codes

Electrical Supply:

RA2-A/RA3-A: 220-240V 50Hz 13A
RA2-G/RA3-G: 230V 60Hz 13A
G version has optional 1.5kVA transformer available to accommodate 120V/1Ph/60Hz supply.

Shipping Specification

  Volume Gross weight
RA2 1.2m3 150kg
RA3 3.3m3 250kg

Overall Dimensions

 

  Length Width Height
RA2 1.72m 0.40m 0.62m
RA3 2.45m 0.71m 1.20m