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To avoid sweltering summers, district cooling plants emerge as a powerful and sustainable solution for a comfortable indoor atmosphere. Unlike individual air conditioning units that strain power grids and offer limited efficiency, district cooling leverages a centralized approach. This means larger, more efficient chillers with optimized operations.
The plants also significantly reduce the carbon footprint by reducing peak energy demand and integrating with renewable options.
Take, for example, the capital city of Finland, Helsinki. Since installing district cooling plants, the city has observed an approximate CO2 saving of 60,000 tons per year.
Despite being such an eco-friendly system, these plants often cause significant noise pollution in the surrounding areas.
A comprehensive acoustic analysis addresses this issue. With proper analysis, noise from the plants can be effectively reduced.
In this blog post, let us explore the role of cooling plants and how sound analysis can be effectively leveraged to mitigate noise.
As noted above, the idea behind the cooling plants is to use a centralized system for air conditioning across multiple spaces. These systems generally have a central plant house with mechanical, electrical, and plumbing (MEP) equipment responsible for producing chilled water.
The following steps are involved in the operation of district cooling plants:
Chilled water produced in the plant house through MEP equipment is supplied to each building through insulated underground pipes.
Cold water flows to the buildings and then passes through the heat exchanger.
As the water passes through a heat exchanger, heat from the building is absorbed.
The hot water goes back to the cooling plant and is used for other purposes, such as as a heat source for heat pumps.
A sound analysis can help make these systems less noisy and more sustainable.
Acoustic analysis refers to scientifically and systematically examining sound waves and vibrations. In cooling plants, the analysis typically involves these aspects:
Mechanical, Electrical, and Plumbing (MEP) equipment produces vibrations that can transmit through structures and create noise.
The analysis involves calculating the optimal level of vibration isolation for each piece of equipment, using dampeners, springs, or other methods to minimize transferred noise.
Before implementing solutions, sound analysis uses specialized software to simulate how noise propagates through the building and surrounding environment.
Simulations consider factors like equipment placement, building materials, and distances to identify potential noise hotspots.
The insights from calculations and simulations guide targeted noise reduction strategies, ensuring efficient and cost-effective solutions.
Possible measures include installing sound barriers and acoustic enclosures, relocating equipment, and even modifying operational schedules.
The water chillers, pumps, cooling towers, HVAC (Heating, Ventilation, and Air Conditioning) fans, AHU (Air Handling Unit), FAHU (Fresh Air Handling Unit), and FCU (Fan Coil Unit) installed at different levels of the building of the cooling plant produces intense noise.
Such noise pollution affects human health, causing sleep disturbance, hearing impairment, and also mental health issues like anxiety and depression. In addition, it also impacts wildlife and the ecosystem.
This way, the noise generated by mechanical, electrical, and plumbing equipment in district cooling plants can significantly disrupt the lives of nearby residents. Therefore, to protect community well-being, it’s crucial to maintain noise levels within limits set by local building regulations.
To effectively combat noise generation, acoustic analysis simulates the combined operation of all MEP equipment. This involves identifying and evaluating primary noise sources, and then optimizing the plant layout for noise mitigation based on the analysis results.
The key steps are discussed in detail below:
The first step of sound analysis is to find out the specific sources of noise within the cooling plants. Engineers can determine which components contribute most significantly to overall noise emissions by thoroughly examining all the MEP equipment.
Next, analysis experts understand how the sound waves propagate. The spread of noise pollution heavily depends on the surrounding environment and includes factors like distance, terrain, and the presence of barriers.
Modeling is done by simulating these conditions so that engineers can analyze and adjust noise levels.
There are many regulations and standards established by various jurisdictions to protect residents from excessive noise pollution. Through acoustic analysis, engineers can compare noise levels against the thresholds, identify areas of non-compliance, and implement solutions to achieve regulatory compliance.
Some mitigation strategies may include:
Engineering Controls: Engineers can install sound insulation materials or silencers on MEP equipment to minimize noise.
Placing Noise Barriers: Noise barriers can be placed around the cooling plants. The height, thickness, and material composition can be determined through the analysis.
Vegetative Buffers: Trees and shrubs act as natural sound barriers, absorbing and diffusing noise waves. To mitigate noise pollution, we can decide on appropriate plant species and their placement around the plant.
Active Noise Control: Noise control systems can also be helpful as they emit anti-phase sound waves to cancel out the noise frequencies.
Mechartés is a global CFD, FEA, Piping, Vibration, and Acoustic Analysis consultancy company with decade-long experience. Throughout its diverse and cross-continent projects, the company relies on ASHRAE Standards, AHRI Standards 885, NC criteria, and local civic building regulation guidelines for studying the acoustic analysis simulation.
Let’s explore one of our case studies on Managing Noise and Vibration in District Cooling Plants.
In this case study, Mechartés used sound analysis to mitigate the noise and vibration in a district cooling plant established near residential areas in the Middle East.
The study focuses on reducing noise generated by MEP equipment (considering all equipment was running simultaneously) and maintaining noise levels in compliance with the building regulations.
Here are the key steps involved in this analysis:
Vibration Isolation Calculation: Determined the optimal isolation levels for each piece of Mechanical, Electrical, and Plumbing (MEP) equipment to minimize noise transmission.
3D Sound Simulation: Modeled the entire plant in 3D using Finite Element Analysis (FEA) software to simulate sound propagation.
Noise Level Evaluation: Analyzed the simulated noise levels to ensure compliance with guidelines outlined in ASHRAE Chapter 48.
The acoustic analysis revealed the plant’s sound decibel level exceeded the allowable range according to ASHRAE guidelines. Mechartés implemented solutions to address the issue, including the installation of:
sound attenuators
acoustic louvers
enclosures
vibration isolators
Simulations were re-run after implementing the modifications.
Most importantly, the acoustic noise level was successfully reduced to 15 – 42 dBA, falling within the acceptable range.
Read the full case study here.
Addressing the noise pollution in the district cooling system is necessary for a sustainable environment. Acoustic analysis is a valuable tool in this regard.
With careful sound analysis, engineers can identify and evaluate the noise sources and implement optimization strategies to mitigate noise.
With an impressive client portfolio, Mechartés is regarded as one of the best global acoustic analysis consultancy companies offering next-generation solutions.
To learn more, talk to our experts now!
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