ACR Journal

CMYK / .ai CMYK / .ai CMYK / .ai acrjournal.uk 29 VENTILATION Some Energy Recovery Ventilator (ERV) products in the current market have embedded CO 2 sensing in the unit, such as those manufactured by LG which are suitable for commercial and residential buildings respectively. These systems constantly monitor the indoor CO 2 level in real-time, which is used to control the ventilation rate automatically according to the measured values. The measured CO 2 level can also be displayed on the wired remote controller. The original design intention of this feature was for energy saving to ensure that the fan is off when the indoor CO 2 level is low. Even if the new Part F for dwellings in England does not require CO 2 monitoring, LG’s residential ERVs have this capability built within the unit. Obviously, the outdoor air intake and the indoor air exhaust of the ERV unit need to be properly managed in the design and installation stage to prevent exhausted air from re-circulation returning back into the building again. These devices can also be integrated into the Building Management System (BMS) to control ventilation for large commercial buildings. If the ERV is set in Auto mode, the CO 2 level is used to control the fan speeds (i.e. link to building ventilation rate) automatically. For example, the typical operation control logic used in LG’s product is as follows: CO 2 Sensor Reading ERV Fan Operation Less than 500 ppm Off 500~700 ppm Low speed 700~900 ppm High speed More than 900 ppm Super high speed When the measured indoor CO 2 level is above 500 ppm, the sensor will activate the fan at a low speed to start to ventilate the building. If the measured value is above 700 ppm, the fan will run at a high speed to increase the ventilation rate. During this process, the sensor will continue monitoring the indoor carbon dioxide level, until the CO 2 level is reduced to under 500 ppm, when the fan will switch off automatically. The threshold values used in the control logic will ensure a healthy CO 2 level indoors. In addition, all LG’s ERV units are able to clean the incoming outdoor air by removing fine particles with high efficiency filters and supply fresh air indoors. These high- performance filters are rated according to ISO EN BS 16890 standard (optional ISO ePM1 75% for the commercial unit and built-in ISO ePM1 95% for the residential unit respectively). Furthermore, the recently lauched residential ERV also has UV nano (i.e. UV-C germicial irradiation technology), a bacteria/mould-resistant heat exchanger and air pathways built within the unit to reduce the risks of transmission of airborne infection in the indoor enviroment. Summary In conclusion, these ERV products, suitable for new-build and retrofit, can meet the requirements of the new building regulation in several aspects to achieve the improved indoor air quality for the occupants, including constant CO 2 monitoring, automatic ventilation control, and preventing ingress of external pollutants with the high efficiency filters. https://www.lg.com/uk/business/ ventilation-solution-erv Commercial ERV