Gen1000 Chamber Sound Reduction
Conviron’s GEN1000 chamber is one of their best-selling plant growth chambers, used by growers, researchers, and students all over the world. These growth chambers are currently producing 60 dBA (A-weighted decibel) of noise, which can be irritating for users that have these chambers in their labs or classrooms. The goal of the student team is to decrease these sound levels to 50 dBA. The chamber must be modified in a way that does not hinder the growth of the plants inside, while maintaining the manufacturing cost of the chamber. Additionally, the team must stay within the project budget of $5000 CAD NRE (Non-Recurring Engineering) cost. The primary element of sound production was identified as the condenser fans in the machine compartment of the chamber. The team researched existing methods of sound dampening and presented these to Conviron. Further research was requested on three of these ideas and was later narrowed down to two due to the feasibility of the solutions in terms of manufacturability and function. The two methods of sound reduction chosen included insulating all surfaces in the machine compartment with sound insulation foam and acoustic louvers to replace the ventilation holes in the back panel of the compartment. A preliminary sound test was conducted which resulted in a baseline average of 62 dBA. A preliminary machine compartment temperature test was also conducted which resulted in a maximum baseline temperature of 35.7⁰C. The machine compartment was then insulated with acoustic insulation foam on all the metal surfaces. Three prototype back panels were made to replace the original panel. The first panel (“Handmade”) was made in the University of Manitoba shop using box brakes and hand tools. The second panel (“Manufactured”) was made with Malach, a metal and machining company. The final panel (“3D Printer”) was made using a PLA (Polylactic acid) filament and a 3D printer, to mimic the shape of an industry standard acoustic louver. These panels were then installed and tested along with the insulation for sound and temperature for 1.5 hours. The Handmade, Manufactured, and 3D Printed panels emitted an average of 60.7, 60.5, and 59.7 dBA, respectively. The recommendation chosen by the team was to insulate the machine compartment and to redesign the back panel using the Manufactured panel design. This recommendation was chosen for its effectiveness in dampening sound and high frequencies, the manufacturability, and its relatively affordable price. The final recommendation came out to $291.74 for two rolls of acoustic insulation foam ($114.37) and for the manufactured panel ($63).