Feature
Clive Donnelly
Dusan Stefanov
Clive Donnelly , mechanical engineer at BD & O Group .
Dusan Stefanov , mechanical engineer at ODA Design & Drafting and airflow , ensuring buildings meet all required IAQ codes and standards .
“ This cleaner environment means less energy is needed to provide the necessary amount of cooling and airflow to maintain system energy efficiency . We have found that UV-C installed even in older systems reduces energy use by 10-25 % on average , reducing carbon footprints ,” says Hector .
“ When it comes to UVC GI ’ s benefits , one way of measuring the effectiveness of UVC GI is based on various case studies using what is called the U-value . We use U-values to measure a cooling coil ’ s thermal performance . The higher the value , the more efficient the operation . In a recent case study of an office block , we saw annual chilled water volume reduced from 28 849 to 18 507 tonnes – a reduction of 35.8 %. Our client saw an annual saving of R10 000 for a single coil ,” Hector says .
“ Offering companies the highest grade of protection from highly transmissible influenzas , tuberculosis and other airborne diseases is a winning sales point in an environment where employers are trying to coax workers back to the office . Employers have enormous choice in premises right now and so decisions can turn on features like air quality and other health benefits . Disinfectant technologies , like UVC GI , deliver selling points as well as cost savings , making the immediate return on investment compelling ,” Hector advises .
TREATING CIRCULATED ROOM AIR AND SUPPLYING FRESH AIR Rickard Air Diffusion specialises in air distribution and has developed a product , the Rickard UV Air Purifier , that treats air with UV light , purifying it of pathogens .
Healthcare organisations and hospital administrators are using UV light to disinfect hospitals with wall mounted units or mobile UV-C units . Mark Rickard , director of marketing at Rickard Air Diffusion , says : “ It combines the protective power of UV-C light and the performance of diffusion to give a diffuser that not only keeps tenants comfortable but reduces the risk of exposure to viruses . Rickards ’ patented UV induction treatment system induces air from the room and through the diffusers ’ UV treatment zone where it is treated . The induction system is quietly powered by the discharge of conditioned air and therefore does not need fans or external power . “ This treatment strategy is particularly effective as it treats circulated room air and supplies fresh air . In this way , pathogens within the room are treated by UV light and the viral load is reduced by adding fresh air . VAV diffusers are also excellent at providing air circulation without creating drafts . Since the velocity drops to below 0.25m / s in the occupied zone , pathogens are less likely to be spread if a contaminant is present ,” says Rickard .
“ If a floor ’ s return air is mixed with fresh supply air as is the norm , we recommend the return air be treated with UV light in
www . refrigerationandaircon . co . za RACA Journal I February 2023 31