INDOOR AIR QUALITY
A shield against indoor air threats
Matthew Maleki explores the protective role of demand- controlled ventilation (DCV) systems in maintaining a safe and healthy environment where traditional ventilation solutions fall short.
Matthew Maleki
Business development manager and IAQ champion at CIAT UK
www.ciat.com T
DCV gathers precise data and intelligently acts on it to optimise the indoor environment
activating them only when required. This targeted approach reduces unnecessary operation and energy consumption. Additionally, DCV improves overall building envelope performance. By maintaining slight positive pressure, they minimise the infiltration of unconditioned air, lessening the load on heating and cooling systems and contributing to substantial energy savings.
he irony about the safe harbours we build to protect ourselves from threats to our health and wellbeing is that,
often, they harbour even more threats to our health and wellbeing. That’s because – due to ever-increasing thermal efficiency – they’re just as effective at keepin g toxins in as they are at keeping the elements out. Between carbon dioxide (CO₂) build- up and volatile organic compounds (VOCs) released from everyday materials, the mounting risks have drawn the government’s declaration that poor air quality is the largest environmental risk to public health in the UK. It’s a sentiment matched by the UN’s assertion that “climate change is the single biggest health threat facing humanity”. Certainly, technology is part of
the problem. But it’s also part of the solution. When it comes to protecting our health and the climate, DCV technology has an important role to play. It is arguably one of the most effective safeguards for indoor spaces, serving as an air quality watchdog and proponent of efficiency and sustainability.
The challenge of preventing indoor pollution Traditional ventilation systems often operate on fixed schedules or manual intervention, resulting in inadequate ventilation or unnecessary energy waste. Systems in unoccupied spaces may continue to churn out fresh air, expending energy without
EIBI | JUNE 2024
tangible benefit. Conversely, sudden spikes in occupancy can overwhelm these systems, leading to stuffy atmospheres and the build-up of harmful pollutants. Here, CO₂ plays a vital role as a
reliable indicator of room occupancy and overall ventilation effectiveness. CO₂ levels increase through our respiration, and as people gather, concentration levels rise. While this doesn’t pose an immediate threat, at high levels, it causes problems like reduced cognitive function and increased fatigue and headaches The most notable threats are
VOCs, organic chemical compounds characterised by intensified volatility, mobility and degradation resistance. These compounds are emitted by myriad sources, such as building materials and cleaning products, contributing to the UK’s average indoor air pollution being 3.5 times higher than outdoors.
Intelligent solution DCV systems offer an intelligent solution to help combat these challenges. Equipped with advanced sensors, they constantly monitor indoor air quality metrics like CO₂ levels and particulate matter (PM) concentrations. This real-time data guides DCV systems to adjust ventilation rates accordingly and on the fly.
The benefits of this invisible shield
are multi-faceted: Tailored Air Quality: DCV ensures ventilation matches current occupancy levels and pollutant
presence. This promotes good ventilation while optimising air quality and can be checked in real-time using IAQ monitors. Comfort and Productivity: Good indoor air quality supports wellbeing and mental focus. Well-ventilated, low-contaminant spaces enhance productivity by up to 11%, boost cognitive performance, reduce absenteeism and promote overall satisfaction. Energy Efficiency: DCV systems
significantly reduce ventilation energy consumption by optimising fresh air intake and operating fans only when necessary. This translates into direct cost savings and a lowered carbon footprint for buildings.
Energy saving A key advantage of using DCV is reducing start-up and shutdown energy loss, common in systems that cycle intermittently throughout the day. DCV runs more continuously, avoiding the energy surge of frequent restarts. DCV systems also intelligently
integrate with auxiliary equipment such as humidifiers and dehumidifiers,
A key advantage of DCV is reducing start-up and shut down energy loss
How DCV Systems Work At the heart of a DCV system lies its air quality sensors, strategically placed to monitor the environment. They continuously provide data that guides the ventilation system’s response. The most common are CO₂ and PM sensors, offering a reliable snapshot of occupancy levels and particulate matter concentrations. Sensors like mixed gas sensors offer a more nuanced analysis of specific volatile compounds in areas where VOCs might lurk (think cleaning product storage, kitchens, or bathrooms). DCV systems use data to adjust
various components, including air mix dampers to control the ratio of fresh to recirculated air, ventilation fans to fine- tune speeds and achieve the desired fresh air exchange, and local heating and cooling systems to maintain comfort while maximising energy savings. This integration ensures that temperature needs are met efficiently, with the DCV system adjusting airflow in consideration of heating or cooling demands to prevent unnecessary work and energy waste.
System design The complexity of a DCV system depends on the specific building and its ventilation layout. Simpler systems might primarily control fan speeds, while more advanced setups include air mix dampers, integrate with humidity control systems, and even interact with automated windows or blinds. Regardless of the complexity, a DCV’s core principle remains the same: gather precise data and intelligently act on it to optimise the indoor environment while conserving resources. DCV systems are a win-win for cleaner air and lower energy bills. By carefully adjusting airflow based on need, DCV reduces the energy drain from powerful fans. When combined with heat recovery technology, DCV dramatically reduces the energy needed to bring in fresh, healthy air. It’s an intelligent way to improve the air we breathe while lightening the load on energy costs. ■
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