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It is a legal requirement in the United Kingdom that comfortable working conditions are maintained for employees; minimum working temperatures are even enshrined in UK law.1
Comfortable working environments have a positive impact on the overall productivity, as well as on a number of health issues such as eyestrain.2 Not only that, but well-maintained indoor environments can improve the energy efficiency of a building.3
Heating, ventilation and air conditioning (HVAC) systems are useful in the effective management of environmental conditions – for example, air quality and temperature. Large numbers of buildings make use of a centralized HVAC system which allows the required infrastructure to be contained in a single section of the building or, in some cases, externally.
Centralized systems generally allow for more straightforward maintenance as there are fewer compressor units spread throughout the building.4
A centralized HVAC system allows all the core equipment for heating and ventilation to be housed in the same area. Networks of ducting are then utilized to move heated or cooled air around the building as required. However, because this area performs as a central hub for the whole building, problems at the HVAC source can become building-wide problems rapidly.
It is believed that gas contamination in ventilation systems from species like carbon dioxide or volatile organic compounds could be a contributing factor in Sick Building Syndrome and other health concerns.5 As a result, advice from the Health and Safety Executive encourages regular maintenance of ventilation units.
Gas Monitoring for HVAC Systems
Centralized HVAC systems are generally used in a range of buildings including offices, banks, schools and other large complexes. This allows for improved aesthetics (the ducting for air transport can be kept discrete) and also means that noise from the HVAC system can be reduced. The compressor units are usually water-cooled and where parts of buildings have differing HVAC requirements, valves can be used to optimize conditions in these areas.
With a centralized infrastructure, gas monitoring systems must be installed in the area. Outdoor air is very often circulated to avoid the build-up of unwanted particulates or gases. Where this may not be possible, air quality can be controlled through ventilation systems.6
In particular, closed-loop ventilation systems that do not undergo exchange need to have careful gas monitoring in place. Carbon dioxide levels are often used as a proxy for air quality. These can be monitored as a means of observing ‘building health’.7
Centralized infrastructure gas monitoring can be installed where all ducting is connected to the source. A key advantage of this approach is that it is possible to inexpensively and effectively monitor everything that happens downstream.
Similarly, carbon monoxide monitoring is important for heating units, as incomplete combustion can lead to the formation of this odorless and toxic gas.
Easy Installation Solutions
Low maintenance sensors that are easy to install are the most suited for centralized HVAC facilities. These can be connected to remote control or data logging systems and offer the ideal gas monitoring solution for environmental safety and optimization.
With this in mind, Edinburgh Sensors has developed a range of OEM nondispersive infrared (NDIR) sensors, all of which offer excellent sensitivity and accuracy, and which only require connection to a reference gas upon installation.8
One such example is the Gascard NG; an NDIR sensor that can detect carbon dioxide concentrations over a number of different ranges. For the relatively low short- and long-term exposure limits seen as part of indoor air quality applications, devices which are optimized for low concentrations of 0-10 % may be ideal.9
This unit’s exceptional limit of detection means that it can detect even the smallest of changes in gas concentration, allowing for rapid response to any potential problem. Additionally, the first-rate zero stability of ±2 % of range, over 12 months, means the sensor can form a dependable part of any environmental control network.
The Gascard NG has been developed to be robust, requiring minimum maintenance, however, all its parts are field-serviceable so that if irregular or unusual maintenance is required, this will cause minimal disruption.
The sensor can be easily integrated into data logging networks and feedback systems where real-time, regular sampling is required. It also offers extra options including the use of data logging software already provided with the sensor, with only a cable connection required to begin using this.
Edinburgh Sensors also offer full pre- and post-sales technical support and the option of bespoke design, meaning that the sensor is also ideal for more complex, custom solutions involving extensive integration or advice.
The Gascard NG has been designed to work effectively within a wide range of conditions and offers pressure, temperature and humidity compensated measurements to adapt to an array of environments. These environments include the potentially highly variable and challenging conditions of many centralized HVAC spaces, in fact, the sensor will remain accurate over 0–95 % humidity conditions.
Rapid and regular readouts are available with a T90 of only 10 seconds. This combination of speed, accuracy, and flexibility makes the device incredibly effective for either environmental or safety monitoring purposes.
References and Further Reading
- UK HSE (2020), https://www.hse.gov.uk/temperature/law.htm, accessed 01/03/2020
- Akimoto, T., Tanabe, S. ichi, Yanai, T., & Sasaki, M. (2010). Thermal comfort and productivity - Evaluation of workplace environment in a task conditioned office. Building and Environment, 45(1), 45–50. https://doi.org/10.1016/j.buildenv.2009.06.022
- Pérez-Lombard, L., Ortiz, J., Coronel, J. F., & Maestre, I. R. (2011). A review of HVAC systems requirements in building energy regulations. Energy and Buildings, 43(2–3), 255–268. https://doi.org/10.1016/j.enbuild.2010.10.025
- Centralized HVAC (2009), http://www.seedengr.com/Cent%20Vs%20Decent%20AC%20Systems.pdf accessed 04/03/2020
- HSE on SBS (2020) http://www.hse.gov.uk/pubns/priced/hsg132.pdf, accessed 03/03/2020
- Li, J., Wall, J., & Platt, G. (2010). Indoor air quality control of HVAC system. 2010 International Conference on Modelling, Identification and Control, ICMIC 2010, 756–761.
- Bhattacharya, S., Sridevi, S., & Pitchiah, R. (2012). Indoor Air Quality Monitoring using Wireless Sensor Network. Sixth International Conference on Sensing Technology, 422–427.
- OEM Sensors (2020), https://edinburghsensors.com/products/oem-co2-sensor/, accessed 28/02/2020
- Gascard NG (2020), https://edinburghsensors.com/products/oem-co2-sensor/gascard-ng/, accessed 28/02/2020
This information has been sourced, reviewed and adapted from materials provided by Edinburgh Sensors.
For more information on this source, please visit Edinburgh Sensors.