CARES – University of Guelph, Ridgetown Campus

Location: Ridgetown, Ontario, Canada
Owner/Operator: University of Guelph “Centre for Agricultural Renewable Energy and Sustainability” (CARES)
Biogas Solution Provider: PlanET

Based at the University of Guelph, Ridgetown Campus, the “Centre for Agricultural Renewable Energy and Sustainability” (CARES) is a hub for applied and adaptive research, training and education, technology transfer, and rural community development in bio-energy and the bioeconomy.

The cornerstone of this Renewable Energy program is a farmscale 250 kW anaerobic biodigester, which converts agricultural and food industry biomass to biogas, which is then harnessed to drive a power generator that creates Electricity.

Predictive Acoustic Analysis of Planned Biogas Operations

Prior to its development in HGC was contracted by PlanET to undertake a predictive acoustic analysis of the planned biogas power generating operations and to investigate the need for noise control measures based on the guidelines of the MOE, including publication NPC-232, “Sound Level Limits for Stationary Sources in Class 3 Areas (Rural).”

Under MOE noise assessment guidelines, power generation equipment is classified as a stationary source of sound (as opposed to traffic noise sources, for instance).  In essence, the sound from a stationary source is evaluated by comparing it to the existing background sound levels during a period of low background sound.  Specifically, publication NPC-232 states that the sound level criterion for a stationary source that can operate during both daytime and night time hours in a rural environment is the greater of the minimum one-hour background sound level or the exclusionary minimum night time limit of 40 dBA at night, at any potentially impacted point of reception.  A point of reception is defined to include any location on the premises of a person (e.g., a residence).

The analysis also considered the sound levels at the closest livestock areas and inside the facility crusher room, resulting from the operation of the proposed bio-gas generators. The livestock areas are located approximately 60 meters southwest of the generator room. The crusher room adjoins a side of the generator room.

Recommendation Generator Room Noise Control Measures 

The site geometry and manufacturers’ sound level data were taken to develop an acoustical model of the site using Cadna/A software. Typical acoustical consulting calculations were also made to determine the proportion of sound inside the generator room that would exit through ventilation openings. The study revealed that the majority of sound would be emitted by engine exhaust stacks, but ventilation-air intakes would also be a contributing factor.  The analysis indicated that with recommended noise control measures in place, sound levels would be within the applicable criteria.  These mitigation measures included the installation of exhaust mufflers, ventilation intake silencers, and acoustical louvres in the generator room. Our recommendations also involved adding a layer of thick fiberglass insulation to the inside of the generator room wall assemblies, and augmenting the interior walls’ acoustical treatments with heavy gauge steel sheets.

Acoustical consulting services delivered:

• Predictive Acoustic Analysis
• Acoustic Measurement
• Noise Assessment
• Detailed Noise Impact Studies
• Noise Control Investigations
• Recommendation of Noise Control Measures