Project
The coffee bar located in the lobby . One of the conference rooms .
• The scope of HVAC engineering services then included delivery of the following :
• Air conditioning to all hotel suites , retail zones , offices and client circulation areas ( excluding the atrium ).
• Fresh air to all occupied zones at a rate of approximately 7.5 litres per second per person .
• Extraction from all WCs , laundry , kitchen and change facilities .
• Mixed mode ventilation of the parking garage areas .
• Stair pressurisation to fire escapes as well as smoke ventilation to the atrium and all other areas over 500m2 .
• For this project no heating provision was made as it was clear through simulations conducted and international weather data that it would not be needed .
• Tempered fresh air ventilation only was deemed acceptable for all of the back of house areas .
The system was designed using a central plant in a redundant arrangement ; two-off chillers at 66 % capacity each , and two-off pumps at 66 % capacity each .
Heat recovery chillers were used to enable efficient heat recovery , while variable speed drives on pumps ( with manual bypass ) were installed for reliability and efficiency . The manual bypasses provided would maximise operator usability and ensure robustness of the design .
Conditioning via above ceiling hideaway units with ducted discharge and diffusers was used as far as possible . The project did not make use of cassettes , midwall or split units , as well as conventional air handling units were avoided to maximise all useable area .
Fan coils were ordered complete with valve and control packages to simplify site installation works . Air diffusion included linear diffusers in high visibility areas , swirl diffusers in offices , and typical round disk and square plated diffusers in general areas . All air diffusion units were electro-galvanised steel or aluminium and were lay-in grilles for ease of replacement and ceiling access when required .
The chiller heat recovery was used to incorporate into the hot water generation system where a heat pump was selected as the optimum choice to meet compliance and space requirements , as well as overall cost of ownership formulated into cost per unit . For the project , energy efficiency interventions in water heating were essential in order to reduce operational costs and improve overall sustainability performance .
The lobby area of the building .
OTHER INCORPORATED SERVICES TO THE PROJECT The scope of plumbing and drainage engineering services above the water heating then included the provision of the water storage at 14 500 litres which equated to approximately 4 days of supply , a water filtration and
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RACA Journal I October 2022 www . refrigerationandaircon . co . za