IEQ Sensor & demand-controlled ventilation

Indoor Environmental Quality (IEQ) concerns not only air quality but also other factors that affect the comfort and well-being of building occupants, such as thermal comfort. IEQ aims to improve the overall living or working environment, considering not only physical health but also the general well-being of the occupants. By optimising IEQ, buildings can promote healthier, more productive and more comfortable indoor environments. Daikin's new IEQ sensor addresses the increasing awareness and importance of indoor air quality, providing an advanced solution for the monitoring and management of IAQ across various indoor environments. Furthermore, this article will present a case study demonstrating the energy-saving benefits of the Daikin IEQ sensor when integrated with our Modular T unit. 


The need for excellent IAQ as a predominant part of IEQ 

Mechanical ventilation significantly improves IEQ by ensuring good indoor air quality (IAQ). In indoor environments, it's not always possible to rely solely on opening windows for ventilation. In many cases, windows may not be present or may not be able to remain open continuously without compromising the thermal comfort of the occupants. In such scenarios, mechanical ventilation systems are essential. These systems draw in filtered outdoor air while simultaneously exhausting indoor air, ensuring proper ventilation and air exchange. This process effectively dilutes potential indoor contaminants such as bacteria, viruses and CO2. 

The term IAQ refers to the quality of indoor air, which has a significant impact on the well-being of building occupants in their daily lives. Traditionally, IAQ has focused on temperature and humidity control in addition to cooling requirements. Today, it encompasses a wider range of parameters, including particulate matter, CO2 concentration, volatile organic compounds (VOCs), humidity, temperature and the presence of other airborne pollutants. Achieving comprehensive IAQ monitoring requires sophisticated and accurate sensors. Currently, almost everything around us can be monitored and tracked, including indoor air and environmental quality. Monitoring IAQ levels not only helps us understand how our immediate environment affects our health and comfort but also enables us to take proactive measures to improve the quality of our living spaces, whether they be homes, offices, restaurants, schools or shops.  Now more than ever, monitoring is essential to assess whether the indoor environment meets acceptable quality standards or needs improvement. This requires the consideration of more parameters and the use of sophisticated and accurate sensors.  



Compliant with regulations & aligned with green building protocols 

According to Article 2, paragraph 66 of the European Commission's new EPBD (EU 2024/1275), Indoor Environmental Quality (IEQ) in buildings is defined as the result of an assessment of the conditions inside a building that affect the health and well-being of its occupants. This assessment includes parameters such as temperature, humidity, ventilation rate and the presence of pollutants. The assessment of IEQ is essential to ensure a safe, healthy and comfortable indoor environment for occupants. This Directive is in line with a wider European legislative agenda focused on improving energy efficiency and sustainability in buildings.  Consequently, the EU urges Member States to incorporate minimum IEQ standards into their legislation to ensure and maintain a healthy indoor environment. This includes adequate ventilation and the introduction of measurement and control devices to monitor and actively manage indoor air quality, which is a crucial component of IEQ. 

Green buildings must meet rigorous quality assessments based on specific rating systems that certify the minimal environmental impact of their design. Among the most well-known rating systems are BREEAM, LEED, and WELL. BREEAM is widely used around the world, with over 200,000 buildings certified and more than a million registered for assessment. LEED is particularly popular in the US and is gaining traction in the EU. Monitoring the IEQ is a crucial requirement in these Green Building protocols not only to minimize energy consumption but also to ensure the well-being of building occupants. For these reasons, demand-controlled ventilation systems with integrated control and monitoring capabilities are increasingly recognised as essential for new buildings and major renovations. The Daikin IEQ sensor meets these requirements by continuously monitoring and optimising indoor environmental conditions. 



Daikin's IEQ Sensor features 

In addition to Indoor Air Quality, the Daikin IEQ Sensor measures environmental quality and comfort, including electromagnetic pollution through noise and light parameters. These aspects have a significant impact on people's well-being, especially in environments where they spend a lot of time.  

Daikin can ensure excellent IEQ with minimum energy consumption by integrating the Daikin IEQ sensor with the Air Handling Unit (AHU). This combination enables effective monitoring and management of IAQ while optimising energy efficiency. The state-of-the-art AHU/ventilation control systems, combined with Demand Controlled Ventilation (DCV), control fan speed and the rate of fresh air filtration based on specific IAQ conditions, resulting in significant energy savings. This integration is essential to minimise energy consumption by avoiding unnecessary air renewal and efficiently managing airflow to meet specific IAQ requirements in different areas of the building. 

Daikin's new IEQ Sensor offers stand-alone installation and includes 12 embedded sensors that monitor 15 different parameters. It connects to Wi-Fi and can be easily configured using a dedicated app, as well as integrated with Daikin on Site - Daikin's remote monitoring and intelligent maintenance solution. Once installed, the IEQ sensor tracks indoor air and environmental comfort metrics and transmits data to Caelum - Daikin's indoor air and environmental quality monitoring platform. This platform provides clear insights into the indoor air and environmental quality of monitored spaces. Caelum also enables reporting and real-time video wall monitoring. The platform also includes a notification system that alerts users when specific parameter thresholds are exceeded, ensuring prompt action to maintain optimal indoor air and environmental quality levels. 





Case Study 



The example application is a waiting room of a large clinic. The ventilation of this room is controlled by a Modular T unit, which must regulate the ventilation based on the number of people present and the size of the room. The maximum airflow requirement is determined based on the expected maximum occupancy according to the EN 16798-1 standard. This applies to both CAV and DCV systems, which differ in the way they operate: 

  • Constant Air Volume (CAV): The amount of air supplied by the AHU remains constant, regardless of external or internal building conditions. This system always operates at the design air flow rate, without feedback from the occupied space. 


  • Demand Controlled Ventilation (DCV): This system is designed to adjust the airflow based on the actual ventilation demand of the environment. It uses sensors to monitor parameters such as human presence, indoor air quality and other indicators of thermal load or air pollution. Based on the data collected by the sensors, the DCV system automatically adjusts the airflow delivered by the air handling units. 

In particular, the air handling units initially operate at constant airflow (CAV). Then, thanks to the quick and cost-effective installation of the Daikin IEQ sensor, a demand-based strategy (DCV) is implemented and the behaviour of the two systems is compared. 

When the waiting room is full, the fans increase their speed to ensure greater air exchange, whereas in the standard case, the fans always operate to ensure a constant design airflow. In this case, the design airflow of 3000 m³/h is only reached for a brief time. 




The graph below shows the ventilation trend throughout the day, illustrating how occupancy-based ventilation increases in the morning, decreases at noon and increases again in the afternoon. 

The graph shows both cases, highlighting the energy savings average in terms of ventilation energy in orange. These savings, for the 8:00 to 19:00 opening hours, can be quantified as follows for the ventilation component alone: 

CAV Case: 

  • 13.1 kWh/day 
  • 2882 kWh/year 

DCV case: 

  • 5.39 kWh/day 
  • 1186 kWh/year 
  • -1696 kWh/year energy savings 




In conclusion, the CAV system operates at a constant design airflow without any feedback from the occupied space. In contrast, the DCV system optimises energy consumption and improves the efficiency of the air conditioning system by reducing the airflow when it is not needed and increasing it when there is a higher demand for ventilation. In addition, the DCV system operates according to actual demand and is cost-effective and easy to install thanks to Daikin's IEQ sensor and Wi-Fi communication, resulting in significant energy savings. 


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