Project for this particular VRF system started to become difficult and got to the point where the hassles of this overshadowed the work that needed to be done , and a decision had to ultimately be taken on a replacement system .
" The product selection was based on meeting critical energy efficiency aspects ."
There were two options , namely a replacement VRF system or a chilled water system . The space constraints and challenges of the previous VRF system would result in similar future challenges , and the fact that there were not really many other options to hide or disguise the control boxes – even placement in the passageways was considered , but this would take away from the building features , so was declined .
Based on these multiple factors it was decided to rather select the chilled water system as the preferred replacement . Two chillers were installed in an allocated space at the back of the building ( the building courtyard ) where space allowed . The chiller platform was built at a higher level in the courtyard zone . The two chillers have a capacity of 200kW each . Fancoil units , with capacities ranging from 2.5 to 5.2kW were installed at various locations in the building .
The required piping installation was all done at the back of the building , entering into the building space from this point , and hidden in pockets , ceilings spaces ( where possible ) or the bulk heads . Everything pipe related was done from the back of the building ( back to front ) so that the building façade was not compromised in any way .
The product selection was based on meeting critical energy efficiency aspects , and the consideration of deploying an environmentally friendly refrigerant – in this case R410a . The chillers , having scroll compressors , have an EER of 2.13 , essentially meaning that they produce more than double an output capacity over the input energy . This type of efficiency was also not available in earlier years when the original restoration was done .
PROJECT CHALLENGES Some of the notable project challenges included the erection of scaffolding in the narrow courtyard area to complete the required work at the plant platform . This area is particularly unbalanced and special manoeuvring was necessary as no access other than manpower could reach this space .
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The building foyer . The floor here is also protected by a specially designed glass ramp .
www . hvacronline . co . za RACA Journal I February 2022 43