Heating, Ventilation, and Air Conditioning (HVAC) has always involved more than simply cooling a space. Today, rising energy costs, stricter indoor air requirements and increasingly specialised manufacturing and processing place even greater emphasis on temperature, humidity, ventilation and air quality management.
A well-designed HVAC system can support occupant comfort, process requirements, productivity and the overall energy performance of buildings. Importantly, for decision-makers in the commercial, manufacturing and industrial sectors, the real value lies in working with an experienced HVAC specialist.
Such a specialist understands clients’ building, process and operating requirements and can translate these into a practical, efficient solution.
Every building is different
Effective HVAC design starts with a simple principle: every building and process has its own requirements. Rather than applying a one-size-fits-all solution, we consider several factors before developing a system. These include the building layout, occupancy, internal and external heat loads, required airflow, filtration, pressure relationships, and applicable safety and ventilation requirements.
For example, our turnkey capability extends from design to fabrication, installation, and commissioning. It also includes coordinating related construction and electrical works, focusing on performance, efficiency, and long-term reliability.
Standard packaged or off-the-shelf equipment can be entirely suitable for many applications. However, these options do not automatically provide the best fit for every building or process. The important point is correct selection and control. Equipment needs to be sized for the actual load profile and selected for the required operating range, rather than simply choosing a unit on nominal capacity.
Modern HVAC equipment may use staged capacity, variable-speed compressors, inverter drives, or other controls to respond to changing loads. Nevertheless, an oversized or poorly controlled system can still cycle excessively. It may operate inefficiently, struggle with humidity control, and wear out unnecessarily. Good design is about matching the HVAC plant to the building’s actual demand and ensuring it can operate efficiently at full and partial load.
Ventilation and indoor air quality
People exhale carbon dioxide (CO₂), while occupied buildings also contain moisture, odours and other indoor contaminants. Outdoor air dilutes these contaminants and helps maintain acceptable indoor air quality.
The required outdoor air quality depends on occupancy and application, in accordance with SANS 10400-0. Ventilation rates vary by occupancy type. Designers may express them as litres per second per person and/or air changes per hour. Therefore, the design must meet the requirements applicable to the specific space.
I cite examples where clients asked us to improve ventilation after indoor air quality assessments identified insufficient outdoor air. In one case, the system was recirculating too much return air and introducing too little outdoor air. We rebalanced the system so that it could introduce the required quality of outdoor air while maintaining overall supply air performance.
We always seek the most practical way to introduce the required outdoor air. However, some installations need dedicated ventilation equipment. Depending on the air-conditioning equipment configuration, the system may have limited capacity to supply outdoor air, or designers may need to develop a separate solution.
In those cases, we can install a dedicated fresh air system and integrate it with the air-conditioning system. Outdoor air also contributes to a building’s cooling or heating load. On very hot or cold days, untreated outdoor air entering a conditioned space can increase the HVAC plant’s energy requirements.
Where appropriate, we can temper or pre-condition outdoor air and consider measures such as heat recovery. These measures help the system meet ventilation requirements without placing unnecessary loads on the main air-conditioning plant. They can also save energy.
Turnkey HVAC projects
The turnkey approach is evident in two recent projects involving specialised process environments. In both cases, climate control formed an integral part of production requirements rather than simply providing occupant comfort.
The first project involved a large-scale central HVAC plant serving multiple controlled-environment production areas. The system provides heated and chilled water alongside multiple filtration stages, including High-Efficiency Particulate Air (HEPA) filtration. These systems maintain tightly controlled temperature and relative humidity conditions.
The filtration and environmental control requirements were significantly more stringent than those of a typical comfort-cooling installation. The temperature-sensitive production process itself shaped the air distribution strategy.
Directing cold supply air onto the product could have caused damaging localised temperature stress. We therefore designed the air movement to avoid direct cold draughts across the sensitive production area and used controlled circulation within the space to achieve a more even temperature. Furthermore, high solar heat gain through the building envelope created another substantial design challenge.
Extreme temperatures occurred within the production environment. The central chiller plant sits remotely from the conditioned area and connects to the air-handling equipment through steel pipework. Its controls coordinate cooling, heating, and ventilation to maintain the required conditions as the load changes.
The second process-cooling project required a simpler solution but equally careful control. Large circulation and ventilation fans manage air movement. However, our main task was to maintain the process medium and supply water at a stable temperature. We therefore cooled the water to a carefully controlled set point suited to the production requirement, using heat exchangers to separate the chiller’s closed water circuit from the client’s process-water circuit.
Rather than passing process water directly through the chiller, the heat exchanger transfers cooling between the two circuits. This protects the chiller water loop while allowing the process water to be managed according to the production application’s specific water-quality requirements.
A new age for HVAC
HVAC technology continues to improve, particularly in compressor control, heat exchanger design, fans, controls and refrigerant selection.
Energy performance should be assessed against actual operating conditions and the efficiency rating of the selected equipment. Using an Energy Efficiency Ratio (EER) of 2.6 as an example, the system provides approximately 2.6 kW of cooling for every 1 kW of electrical input at the stated rated condition.
The higher the EER, the less electrical input the system requires for the same cooling duty. Also, R-32 is one of the lower Global Warming Potential (GWP) refrigerants now used in selected air-conditioning and chiller applications. However, refrigerant choice must always suit the equipment type, capacity, safety requirements and application. However, I caution that savings vary from project to project. They depend on the efficiency of the existing plant, operating hours, controls, load profile, and replacement HVAC technology.
In conclusion
The opportunity for performance and sustainability improvement is not only in replacing equipment. Correct sizing, controls, commissioning, and ongoing optimisation all contribute to HVAC energy efficiency and savings while maintaining the climate conditions that the building or process requires.
Ultimately, a ‘chilled’ HVAC partnership means more than installing cooling equipment. 
It requires an experienced specialist who understands each building’s operational demands and can deliver a tailored, efficient and reliable solution.
By combining careful design, appropriate technology and ongoing optimisation, we aim to help clients achieve the right balance between environmental control, productivity and energy performance. For businesses operating in demanding environments, a ‘chilled’ HVAC partnership can provide a practical route towards long-term operational reliability and improved energy efficiency.
Alin Gomes | Director | Industrial Climate Engineering (ICE) | mail me |
