Project design point and then a condenser re-heat coil is used to reheat the air back to 20 ° C DB which results in 50 % RH inside the zone .
SYSTEM COMPONENTS USED Standalone AHUs with dedicated direct expansion ( DX ) systems were selected . A chilled water system with AHUs would have been a good option , however it was not viable due to the distance that separated each AHU .
Jet nozzle diffusers were selected for air distribution in the room . These diffusers allowed the use of minimal ducting and also allowed us to steer clear of existing racking and rather use open space to run ducting and rely on the good throwcharacteristics of the diffusers to get air distributed .
EFFICIENCY AND SUSTAINABILITY ASPECTS OF THE SYSTEM Heat recovery from the refrigerant was used in the dehumidification cycle . Hot gas leaving the compressors was diverted through the re-heat coil before it entered the condenser . This provided “ free ” heat for re-heating the air before it was supplied to the space .
Below one of the mezzanine floors .
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Installation of the vertical external supply air ducts was a challenge on this project .
RACA Journal I September 2022
The air conditioning design : second floor mezzanine division of existing cold room . www . refrigerationandaircon . co . za