www . refrigerationandaircon . co . za RACA Journal I February 2024 31
Project
Renovation work commences .
The design incorporates the separation of occupied areas and circulation areas . It was important to keep the solar heat gain low , therefore glazing and roof insulation were heavily considered . The system could cater to a lower demand for cooling .
The following design criteria were applied in the design and configuration of all technical systems and services :
• Adequate capacity : load handling capabilities to meet present and future requirements .
• Reliability : under all circumstances .
• Adaptability : ability to cater for changes in future technology and expansion without infrastructure modifications .
• Flexibility : simplicity of operation and ability to cater for changes in occupancy .
• Maintainability : ease of maintenance and totally serviceable with locally available components .
• Cost-effectiveness : minimised capital and long-term operational costs .
• Energy efficiency : the systems must operate at optimum efficiency and minimum energy costs .
• Sustainability .
• Safety : the designs must be performed with due consideration given to the circumstances of the patients and the environment .
• Security : consideration must be given during the design process to potential incidents of equipment vandalism and improper use and handling .
The impact of the design choices made during the project is significant . The conversion of Wits ’ Flower Hall into an Engineering Analytical Laboratory allows for space optimisation and meets the University ' s requirements for increased academic and office space . The integration of an innovative HVAC system contributes to the sustainability goals of the institution while providing an efficient and comfortable environment for occupants .
THERMAL COMFORT AND INDOOR AIR QUALITY Occupants ’ thermal comfort is the primary objective in radiantly heated or cooled space . To provide an acceptable thermal environment for the occupants , the requirements for general thermal comfort shall be taken into account by using the index of predicted mean vote ( PMV ) or operative temperature ( to ), and local thermal comfort – for example , surface temperature , vertical air temperature differences , radiant temperature asymmetry and draft .
In laboratories and exam venues , thermal comfort is crucial for the occupants ' productivity , concentration and overall wellbeing . Chilled beams offer several benefits in terms of thermal comfort :
• Zoned cooling : Chilled beams provide zoned cooling , allowing different areas within the facility to be controlled independently . This feature is particularly useful in laboratories and exam venues , where maintaining different temperature requirements in different spaces is often necessary . The difference between exam venues and laboratories is the set points required for cooling . It must be noted that the ability to cater to the different heat loads and temperature set points is ideal for the design .
• Low air velocity : Chilled beams operate with low air velocities compared to traditional air conditioning systems . This reduces drafts and the sensation of moving air , creating a more comfortable environment for occupants .
www . refrigerationandaircon . co . za RACA Journal I February 2024 31