Q: How important is the collaboration between the architect and engineer in ensuring the highest level of indoor air quality for new sustainable buildings?
A: It is essential that architects and heating, ventilation and air-conditioning (HVAC) engineers work closely together to ensure a reduction in heat gains, maximising a building’s energy efficiency and ensuring that building shafts are designed to be prepared for mechanical installations of HVAC systems and related drainage points.
HVAC systems require a highly technical engineering application. In my experience, energy efficiency, together with environmental concerns, is at the forefront of clients’ concerns. All stakeholders in the process therefore, from design to beyond construction, need to ensure that client specifications are met, that compliance to regulations is applied, and that cost-efficiency is fully inclusive – be that installation, maintenance and future running costs.
Our company, for example, worked with consulting engineers Spoormaker and Partners on the design of the Sandton Oncology Centre. This project required our engineering input over a seven-month period, and we were on-site to ensure the installation crew did not encounter any hiccups. The feedback from the client is that they are achieving much better cost-efficiencies than they had expected.
Q: What HVAC trends are the most popular, and why?
A: Digital variable multisystem (DVM) technology with heat recovery has proven to be the most cost-effective way to meet ever-increasing and changing global energy efficiency standards. In the past, chilled water systems were widely used, and these required a specific volume of water that needed to be cooled or heated in order to alter the temperature of even a fraction of the building.
One of the products we stock, the Samsung DVM-S is a great example of new technology – its high energy efficiency and low fiscal footprint is the ideal solution for any type of building, given its inverter heat recovery characteristics. And a big plus is that it can be connected to a WiFi network, LAN or the internet.
Q: How cost-effective/feasible is retrofitting HVAC systems?
A: Cost plays a very small role in the decision to replace a system, considering that even a current system may be redundant in a couple of years.
The latest outdoor and various indoor units, for example, are exceptionally unobtrusive – they require little ceiling space and minimal penetration of the building. So a retrofitted system should not cost much more than a new system that would be installed at the beginning of a project.
Q: How do you measure HVAC effectiveness versus space and layout of the building?
A: The amount of fresh air required is calculated by determining the number of occupants in the building and their activities. Extraction is calculated based on the number of ablutions and kitchens in a building and, overall, what the entire building’s use is. Potential contaminants, such as carbon fumes in car parking areas, mould and moisture, pest controls and so on also need to be considered.
Location is an important aspect, as are the number of windows and, obviously, the size of the building. We also need to know what material the building is made of and the type of drainage/plumbing solutions. Power supply is crucial.
HVAC does not have to be connected to the main grid, provided that the alternative source can generate a constant and stable voltage.
Q: How are comfort levels of individuals taken into consideration?
A: The DVM-S technology supports zone control, enabling users to adjust individual climate settings to suit personal comfort preferences. Ambient temperature is widely regarded by manufacturers as 23°C.
Q: How does HVAC rate on the Green Building Council of SA Green Star scorecard?
A: It’s a very comprehensive scorecard with points awarded based on the percentage improvement of the actual building compared to the notional building in terms of base building. Basically, carbon emissions are measured on a linear scale, with zero points representing no improvement and 20 points representing a building with net zero operating emissions.
The base building’s carbon emissions include energy used for heating, cooling, ventilation, non-tenant (common area) lighting, external lighting and so on. However, efficient lighting and automatic daylight control can be included insofar as they reduce the cooling load of
Q: Just how reliable are computer-based HVAC simulations?
A: Simulations have become more popular given the complexities of sustainable design and the number of sub-components that HVAC may require. But the technology around HVAC computer simulations is only as effective as the data received.
Used correctly, they can be an incredible aid for design engineers in estimating the impact of the HVAC system on a building, enabling them to adjust levels prior to construction to achieve the best efficiency possible.