نوع مقاله : مقاله پژوهشی

نویسندگان

• امیر کلانتری‌فرد ¹
• سید عباس آقا یزدانفر ²
• محسن فیضی ³

¹ دانشجوی دکتری معماری، دانشکده معماری و شهرسازی، دانشگاه علم و صنعت ایران، تهران،

² دانشیار، دانشکده معماری و شهرسازی، دانشگاه علم و صنعت ایران، تهران، ایران,

³ استاد، دانشکده معماری و شهرسازی، دانشگاه علم و صنعت ایران، تهران، ایران.

چکیده

بحران انرژی یکی از جدی‌ترین دغدغه‌های امروز جهان بوده که بخش عمده‌ای از مصرف انرژی در ساختمان‌ها است. یکی از بهترین و مقرون به صرفه‌ترین روش‌های دستیابی به آسایش حرارتی و کاهش مصرف انرژی، استفاده از تهویه طبیعی است که در شهرهای پرجمعیت امروز غالباً امکان تهویه طبیعی از طریق پنجره‌ها به علت ورود آلودگی صوتی همراه با جریان هوا به درون ساختمان، وجود ندارد. هدف این پژوهش دستیابی به راهکاری است که بتوان همزمان با استفاده از تهویه طبیعی و جریان هوا از محیط به درون بنا، از ورود آلودگی صوتی همراه هوا جلوگیری نمود. برای این منظور در ابتدا سامانه‌های ایستای تهویه طبیعی مورد بررسی قرار گرفت و نقاط ضعف آن‌ها با توجه به شرایط شهرنشینی امروزی بررسی شد. سپس سامانه‌های ایستا و پویای کنترل صوت بررسی و از ادغام این سامانه‌ها و با الهام از سامانه عملکردی مکانیکی صداخفه‌کن اسلحه‌ها، نمونه‌ای از یک بازشو طراحی و سپس از طریق شبیه‌سازی با استفاده از نرم‌افزارهای حرارتی و CFD مورد آزمایش قرار گرفت. با استفاده از تحلیل‌های مورد نظر، بازشویی طراحی شد که می‌تواند در حین عبور جریان هوا، مانع ورود آلودگی صوتی به درون ساختمان شود. نمونه‌ای از این بازشو ساخته و مورد آزمایش قرار گرفت. آزمایشات نشان داد که بازشو مورد نظر باعث کاهش شدت صوت جریان هوای ورودی به بنا تا ۱۰ دسی بل می‌شود.

تازه های تحقیق

- ارائه راهکاری نوین جهت استفاده از تهویه طبیعی در محیط‌های دارای آلودگی صوتی.
- آزمایش عملکرد بازشو طراحی شده در یک آزمایشگاه که همانند یک کلاس کوچک تجهیز شده است در ساعات غیر اداری.
- الهام از سامانه عملکردی مکانیکی صداخفه‌کن و ادغام هندسه متخلخل در طراحی یک سامانه ایستا نوین.

کلیدواژه‌ها

• تهویه طبیعی
• آسایش حرارتی
• کاهش مصرف انرژی
• عایق صوتی
• سامانه‌های ایستا و پویای کنترل صدا
• سامانه‌ی صداخفه‌کن

عنوان مقاله [English]

Reducing noise pollution through the building openings (Preventing inward airflow noise through opening design)

نویسندگان [English]

• Amir Kalantarifard ¹
• Seyed Abbas Agha Yazdanfar ²
• Mohsen Faizi ³

¹ Ph.D. Candidate in Architecture, , School of Architecture and Environmental Design, Iran University of Science and Technology, Tehran, Iran.

² Associate Professor, School of Architecture and Environmental Design, Iran University of Science and Technology, Tehran, Iran,

³ Professor, School of Architecture and Environmental Design, Iran University of Science and Technology, Tehran, Iran.

چکیده [English]

Extended Abstract
Background and Objectives: In today’s densely populated cities, it is often not possible to use natural ventilation through windows due to the noise pollution and the airflow into the building, while natural ventilation is one of the best and most cost-effective ways to achieve thermal comfort and reduce energy consumption. This study aims to achieve a solution that can prevent noise pollution while benefitting from natural ventilation and the natural airflow from the environment into the building.
Methods: In order to achieve this goal, passive natural ventilation systems were first inspected, and their performance and weaknesses were analyzed according to today’s urban conditions. The passive and active sound control systems were also studied. A prototype of an opening was designed and built by integrating these systems features with a porous geometry, inspired by the functional mechanical system of the silencer. The designed opening was tested in a laboratory that is furnished like a small classroom during non-office hours with no ambient noise pollution. While the airflow passed through the opening, different waves with frequencies of 125, 250, 500, 750, 1000, 2000, and 4000 Hz and intensities of 35, 45, and 55 DB were produced for 5 seconds each outside of the opening, and they were recorded by a microphone inside.
Findings: The system’s operation has been tested at 35, 45, and 55 dB at all frequencies. On average, the system can reduce the sound intensity of inward airflow by 9 decibels. The intensity reduction rate is lower at higher frequencies than at higher frequencies, meaning that the system is more efficient at lower frequencies. The decrease in sound intensity depends on the frequency of the input sound, but the sound intensity of the input sound does not affect the system’s performance. At 400 Hz, the system can only reduce the sound intensity by 5 decibels. If the best performance is related to the frequency of 125 Hz, the sound intensity was reduced by 12 decibels. At 35 decibels, the difference between the decrease in sound intensity at frequencies of 1000 and 200 Hz (1.8 dB) is greater than the decrease in the coefficient of intensity at frequencies of 2000 at 400 Hz (5. dB). At 45 decibels, this factor is for frequencies 1000 to 2000 Hz (1.4 dB) and 2000 to 4000 Hz (dB 9.). Also, at 55 dB, this factor is for frequencies 1000 to 2000 Hz (dB 1) and 2000 to 4000 Hz (dB 1.4). As predicted, the effect of system performance depends on both the frequency and intensity of the reference sound (sound produced). The system’s performance is not known exactly due to the amplitude of frequencies in the environment, the intensity of these sounds, and their synchronicity. Still, the results show a significant reduction in sound intensity after passing through the porous cavities.
Conclusion: The effect of system performance on reducing sound intensity for frequencies (125, 250, 500, 750, 1K, 2K, 4K) Hz at reference sound intensities (produced sound) of 35, 45, and 55 dB in the laboratory was investigated. Using a system of porous cylinders effectively reduces the volume of inward airflow sound. One of the main advantages of this project is that it is not dedicated to a specific climate and can adapt to different environmental conditions. Due to the operation of the opening (using the difference between cold and hot air pressure), air compensation is created regardless of wind. By using architectural climate design solutions, this opening can be used in suitable climates. The system performs best at low frequencies and poorly at high frequencies, so it can be concluded that the higher the reference sound frequency, the poorer the system’s performance in reducing noise and vice versa. From the data analysis, it can be seen that at high sound intensities, the higher the frequency of the waves, the more the system performance decreases. On average, the system reduces the sound intensity of the inward airflow by 9 decibels. It performs well against different frequencies of the natural environment that are produced at different intensities. It is possible to use the designed opening and conventional windows simultaneously to provide proper light and view without restrictions and benefit from natural ventilation without noise and dust pollution through the openings. Unlike ANC systems, the designed system is static, and this shutter operates without energy consumption.

کلیدواژه‌ها [English]

• Natural ventilation
• Thermal Comfort
• Energy Reduction
• Sound Insulation
• Passive and Active Noise Control Systems
• Silencer System