Evaluation of fric-tion coefficient is done by subtracting the pressure differ-ence at substituted duct from static pressure difference of silencer. Under the condition of free sound field (free space), the sound wave of the point source follows the spherical divergence law, and the sound power level is used as the point source evaluation quantity. The sound attenuator’s low pressure drop has been achieved by designing the acoustic baffle elements completely according to the basic laws of aerodynamics. As the sound waves pass through the attenuator, they are absorbed into the insulation and are. Duct Noise Calculation Excel Sheet - Sound Attenuation Download : Duct Noise Calculation Excel Sheet - Sound Attenuation. Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation. Original number is in A and the percentage to reduce by is in B. The SNR is 10 log (. 11/04/2017 06:31:00 PM. See our popular inverse. Celebrating 15 Years. FUNCTIONS THAT HAVE NOT BEEN REPLACED ARE: Calculation of the whole duct system Cross-talk External noisE In this paper, a new open source acoustics calculation platform, Trace, is presented. Address: 6122 Benjamin Road Tampa, FL 33634Speed of sound in water at temperatures ranging 32 - 212°F (0 - 100°C) - Imperial and SI units. Matching T Attenuator A two part calculator which gives ideal and preferred value resistors, showing most formulas used and a link to the others. The figure below can be used to approximate the Directivity coefficient - D - for typical locations of the receiver and the sound source. You have to read ISO 12354 standard. 5 63 125 250 500 1000 2000 4000 8000 LEQ (dB) 79. In case the absorbtion coefficient has been defined. us to produce and deliver attenuators as efficiently and quickly as we can. Al Mulla Industries offers you a wide range of Sound Attenuators that include Square &. Adjustable Attenuator. When analyzing the extent of project-related noise, consider the. Thescribes the measuring of sound attenuation as well as the measurement of minor loss coefficient. 0. STC numbers are determined based on the ASTM 413 standard. What is the best sound attenuation product you will recommend. This program does it for you. Use the calculator below to calculate the attenuation of sound from a line source, using either metric or imperial units of distance (i. Sound Attenuation Spreadsheet; Preliminary Pipe Sizing;. These are used to lower the sounds generated from fans and HVAC systems. 002 s . All computational steps are described by follow-ing equations. You have to create then an excel sheet for price calculation. The sound pressure falls to 1/2 times (50%) of the initial value of the sound pressure. 1 27 24 21. NC/RC Chart. 1 PurposeThis article aims to provide a detailed explanation of sound attenuator calculations, including the concept, factors affecting sound attenuation, and the calculation methods used. 95 shares. كيفية حساب تخفيض مستوى الضوضاء في أنظمة التكييف، و إختيار كاتم الصوتThe tool below allows for calculation of the Lw of Industrial Generators (excluding the driver) based on the calculations in Engineering Noise Control. Sound attenuators ALPHAfon-SA are used in applications in air ducts installations that require noise reduction and low pressure drop. A wide range of models and features to choose from. Because of their long time experience with KNC’s HVAC equipment vibration and architectural noise separation products and. 2 40. Individual modules can be assembled into assemblies to match most any size of duct. But for the NEC Acostix Modules: AX-C : Acostix ™ all design and calculation modules. This is intended to be a tool for understanding and implementing the calculations of ISO-9613 and creating interactive models that are freely accessible. OF SYSTEM: DATE FAN DETAILS Room/Area Served FAN DUTY SWL 1K 2K 4K 8K Spectrum DUCT ATTENUATION Length (m) PNC65 End Reflection Loss PNC60 SOUND POWER LEAVING PNC55 Sound Power to Room % PNC50 Room Size m3 PNC45 Reverberation Time secs PNC43 REVERBERANT SPL PNC40 Sound Power to. 10/10/2018 10:06:00 PM. References 1 and 2 are herein referred to as ISO/ANSI1,2. Acoustics — Determination of sound power levels of noise sources using sound intensity — Part 3: Precision method for measurement by scanning. Lebanon - Naher El Mott, INDUSTRIAL CITY . If it is a matter of pure absorption this occurs at the square of the frequency f, or at a higher exponent if attenuation is due to scatter. The Lay-In Service Reduces Project Risk. From configuration to. An online Preferred Noise Criterion (PNC) calculator. Spreadsheet for HVAC systems racket and sound attenuation calculation. The natural attenuation elements, such as ductwork, plenums and fittings, etc. Application Guide AG 31-010 5 Sound Basics General Sound is defined as a disturbance in an elastic medium that can be detected by the human ear. The ASJ model as defined in Equation 7 has been implemented in an Excel spreadsheet to calculate the expected sound propagation along the validation test. NEC Acostix. 20. These. Click Cost-free MEP Calculate Excel Sheets, AutoCAD Design, and Training Courses for HVAC, Firefighting, Plumbing and Electrical Software Design. Some of the calculation results are comparable with some input data envisaged in standardized calculation: cf. The software allows the prediction of stacks directivity, of atmospheric sound absorption. door air loss duct weight & flange drilling pressure loss spreadsheet sound attenuation spreadsheet preliminary pipe. Removal of hearing protectors severely reduces protection - online tool. Download free mep calculation excel sheets, autocad drawings, and training courses for hvac, firefighting, plumbing and electrical systems design. The splitter / attenuator key goes programmed regarding your individual requests. Excel sheet for all generator and transformer room ventilation calculation. 0015 W) / (10-12 W)) = 91. Take the NRR of 33 and derate it with the following formula: (NRR - 7) / 2. 00002) = 194 dB RE 20µ Pa Note: 20µ Pa is another way to write 0. Calculate room noise levels via spreadsheet CDROM data. By clicking the button, you allow us to provide you with an excellent website experience and easy shopping processes. P, CC series circular attenuators priate) sound attenuation effects from the unit sound power (Lw). Duct and bend attenuation figures should be entered against lines b. 1 Sound attenuator casing MS 2 Connecting subframe 3 Splitter MK Important notes Safety Correct use Splitter sound attenuators and sound attenuator splitters are used for the reduction of fan noise and air-regenerated noise in ventilation and air con-ditioning systems, for example in air handling units or ducts. And. Airwellcare Sound Attenuators design flexibility and Sound Calculations allows to adjust : • Attenuator Splitter Thickness • Airway Gap between splitters Approximate attenuation per metre run is shown in Table 2. This PDF document covers topics such as sound sources, sound transmission, sound criteria, sound attenuation, and sound analysis. Explore. The room constant can be calculated as. 5k ohm. This next calculator is used to convert from Watt to dB as a measure of sound or noise level. The L-pad Attenuator is a simple resistive voltage divider network which can be used as a fixed passive attenuator to reduce the amplitude of a signal. The ASJ model as defined in Equation 7 has been implemented in an Excel spreadsheet to calculate the expected sound propagation along the validation test. Comment: This should work, but note that if the adjustable attenuator were to be turned to its. Table 2: The attenuation of straight unlined rectangular ducts - dB per meter Table 3b: The attenuation of mitred bends with long chord turning vanes or radiussed bends. c c c is the speed of sound in air (v = 343 m s v = 343 frac{ ext{m}}{ ext{s}} v = 343 s m ); V V V is the volume of the resonator; S S S, the cross-section area of the aperture; and; L L L, the aperture's length. where R1 is the shunt resistor (to ground) and R2 is the series resistor. The quietest fan powered terminal in the market is the TFS-F Fantom IQ™. A. Sound Attenuators. Type. 7. Spreadsheet for HVAC systems racket and sound attenuation calculation. 1 Calculating an NR value To calculate the NR value, the noise level in each 1:1 octave band is compared to the values in the NR table (see page 11) for each corresponding band. Sound Attenuation and Test Strategies for Generator Set Installations • Describe the fundamentals of acoustics relative to generator set installations. 3 71. Center Frequency 500 1K 2K 49 49 48 50 50 50 73 69 65. Description The attenuator housing is made of galvanised sheet steel. Helmholtz resonators excel in muffling sounds when designing concert rooms or studios. Width B. The equation that gives an approximation of sound power from the sound pressure of a noise source is: Lw = Lp + 10*LOG (A/A0) Where: Lw = Sound Power Level. Because sound travels effectively in the same or opposite direction of airflow, downstream and upstream paths are often equally important. Caterpillar offers the industry’s widest range of diesel, gas and rental generator sets, automatic transfer switches, uninterruptible power systems, and switchgear. This pdf document introduces the features and benefits of various acoustic products, such as acoustic panels, acoustic baffles, acoustic doors and acoustic. We also undertake sound attenuator. sound attenuator calculation excel. Calculate the loudest possible sound at standard atmospheric pressure (101. Sound Power from Sound Pressure. 10 inch for a sound attenuator design for a duct velocity of 500 fpm compared to a static pressure. The difference in. Attenuator calculator PI Attenuator calculator T Bramham matching transformer Butterworth filter designer Cascaded Noise Figure calculator. 1/08/2019 12:29:00 AM. This should be done in frequency bands. Download Free AutoCAD Blocks for HVAC Systems Design dwg. txt) or read online for free. Application of sound attenuator DZ-3 DZ-3 sound attenuators are suitable to attenuate industrial machinery noises and for special applications in the air-conditi-oning engineering. Sound Pressure (Pa) Sound Pressure is the sound force ( N) acting on the surface area ( m2) perpendicular to the direction of the sound. 4 Safty factor 10%. 6 Return duct Sound attenuator Fire damper Sound attenuator 0. The total sound pressure in the tube can be measured by a microphone and is given by the sum of the two. ) The silencer should not be included in the initial calculation. The attenuation values printed in Table E1 of Normative Appendix E “Typical Sound Attenuation Values” , often called transfer functions, are used as deducts to compute the space sound pressure. Single, Double or Triple. SOUND ATTENUATOR SOUND ATTENUATOR RECTANGULAR Low Pressure Drop Sound Attenuator Silencer Splitter • is constructed of solid and perforated metal that is located inside the silencer which protrudes into the air stream and house the acoustic media. Identify the highest NC curve intersected by the plotted sound pressure level. Assessing whether an attenuator would reduce noise effectively enough for a particular situation usually requires complete equipment noise data and attenuator insertion loss. Another application of Helmholtz resonance is in the exhausts of vehicles: creating a suitably sized exhaust. Sound - Attenuation and Speed vs. Sound - Attenuation and Speed vs. In this article, we will show you how. To calculate the level at the ear, enter the measured C weighted sound level along with the protector's SNR value, which should be marked on the protector packaging or associated paperwork. You have to create then an excel sheet for price calculation. The sound pressure measured twice as much gives 6 dB more level. The sound power from a from a tool is 0. In column C, enter = (B1/A1). 1. Sound level calculation To determine the sound level after using an attenuator, the insertion attenuation is to be deducted from the level of the band of the fan using the fre-quency band and the total sound level calculated from this. ). A number of apps are available for both iPod and Droid smart phones that can measure the room sound power, by octave band. 1, is assumed to be infinitely wide (in the x dimension) and to have a height in the y dimension equal to h. CAIROX. 1 Noise Criteria 76. A = Measurement Surface Area of the Source. When autocomplete results are available use up and down arrows to review and enter to select. To calculate the percent difference between two numbers correctly, carry out these steps. (W. g. 6 Return duct Sound attenuator Fire damper Sound attenuator 0. Decrease by %: Use the formula =A1* (1-B1). The box “swallows” part of the noise and thus reduces the overall SWL level at the tower. ISO/TC 43/SC 1. Center Frequency 500 1K 2K 49 49 48 50 50 50 73 69 65. Calculation of the sound level L 2, which is found at the distance r 2: Reference distance r 1 from sound source m or ft: Sound level L 1 at reference distance r 1 dBSPL: Search for L 2: Another distance r 2 from. Step 3: Multiply the result by 20 to get the final result. Free spread sheet forward noise and sound weakening in HVAC systems. 4 48. Request an Estimate. To calculate an A-weighted value: 1. FAQ. RT Series - Rectangular Attenuators The RT series is ideal for general HVAC purposes and suitable for industrial applications. Makes sharing these projects with colleagues simple and easy. Sizing Pressure Relief Outlets, Door Air Loss. To calculate the airflow needed in a room, the pressure and temperature. (See ASHRAE’s “System Design Procedures”1 for more details. The Pi attenuator (Pi pad) is a specific type of RF attenuator circuit which resembles the shape of the Greek letter for Pi. 13. 03 System effect Fresh air louver 0. ProSilencer is the follow-up to ProAc, however not with the exact same functionality. In the ZS box, type a value of 75 Ω. Using a Noise Calculator. Sound Frequency and Air Humidity The speed and attenuation of sound in moist air varies with sound frequency and air humidity. Long coax cable: Loss 3 dB attenuation (reduction to half the level) High power 10 watt amplifier: Gain=30 dB (increase in signal level by a factor of 1000 times. com. Get the K factor. It shall include the following modules: AX-01, AX-02, AX-03, AX-04, AX-06 and AX-07. For this reason, an advanced design procedure is not necessary to reduce noise components above the cut. 48The sound pressure that is considered as a limit for the human audition is 2 · 10 -5 Pa. BP of Engine Introduce BP of Piping & Elbows Super Critical Grade S. 95 shares. xls / . The distance from person 2 to bus stand is RΓéé = 15 m. Description. The formula is as follows:Range, mean and standard deviations for sound attenuation rates for confined bubble curtains achieved on WSDOT projects. **Note: All of our calculators allow SI prefix input. To do so, repeat step 1 from above and input the desired Sound pressure level at. 370. Gentlemen, may I turn your attention to an Excel spreadsheet I created for the calculation of resistor values for stepped attenuators in shunt (i. . 249) Multiply the total of above by a safety factor of 1. etc. Pressure Loss in "w. Attenuator Pressure Loss A sound attenuator restricts the passage of airflow through it. Lp1 - sound pressure level at location 1 (dB) R1 - distance from source to location 1 (m, ft) R2 - distance from source to location 2 (m, ft) Example - Noise from a Machine The noise from a machine in distance 1 m is measured to 110 dB. 9 Ω, R₂ = 3,062 Ω, and R₃ = 50. The disruption of the sound pressure wave and the reduction of noise is called attenuation - Sound Pressure Level vs. Calculation methods for predicting attenuation of parallel baffle type silencers For use in power plant ducts and exhausts Master’s Thesis in the Master’s programme in Sound and Vibration DARIO BOGDANOVIC Department of Civil and Environmental Engineering Division of Division of Applied Acoustics Vibroacoustics Group 2. Pasternack's RF Free Space Path Loss (FSPL) Calculators is the ideal measurement tool that allows loss or attenuation of signal strength calculations between two antennas. In its simplest form, a. • Units are tested by ETL Intertek in accordance with AHRI. The splitter / attenuator key goes programmed regarding your individual requests. LW is the power specified in Watt. sound attenuator calculation excel. Among the advantages of the SILDIS ® calculation software, it is. The method is based on a measurement of sound pressure levels and a set of sound pressure criteria curves ranging frequencies from 63 to 8000 Hz - and a. source off maximum sound pressure level = nr 40 table 1 room and terminal effect fig. g. Calculate the International Standard Atmosphere at 1000, 11,000, and 20,000 m with extended=true to implement the mathematical representation of the International Standard Atmosphere values to between -5000 meters and the mesopause. Kinetics offers the design and engineering assistance to integrate our line of duct silencers/sound. Duct Quantity TakeOff Sheet (HVAC System) October 31, 2020 In "Download Notes". Figure 3. Flexible Sound attenuator The Splitter / Attenuator Product Key. For a particular volume knob setting on my sound card embedded with a headphone pre-amplifier, I would like to determine the output in dB SPL from the headphones. Now we add all of these values together, log this value and multiply it by 10 to give the final dB (A) value. The sound pressure level of a fan is not very useful since environmental factors apparent when the unit was measured may or may not be present in the actual location of the plant. The platform is built as a Microsoft Excel Add-In and contains tools for common acoustics calculations, mainly centred around mechanical noise, simplified environmental noise, and basic room acoustics. Plenum as sound attenuator. 2. 14. These excel worksheet's includes the following conversion and useful sheet which are mentioned below :-. These are used to lower the sounds generated from fans and HVAC systems. P, CC series circular attenuators us to produce and deliver attenuators as efficiently and quickly as we can. Access Acoustic Calculator More technical support below Tools. Sound Frequency and Air Humidity The speed and attenuation of sound in moist air varies with sound frequency and air humidity. Duct Sizing & Estimation of System Pressure Loss. It is a very wide range, so, to handle these quantities more easily the unit usually used is the decibel (dB), which is a logarithmic scale relative to a reference level. 00002 Pa. Find the % of a total: Put the total in column A and number completed in B. The platform is built as a Microsoft Excel Add-In and contains tools for common acoustics. Roomside. Read More. 00002) = 194 dB RE 20µ Pa Note: 20µ Pa is another way to write 0. Download Free Arabic and Kufi SHX AutoCAD Fonts. HVAC. pdf), Text File (. way to verify the sound power level of a unit is through a laboratory test or the sound intensity method. Shop. Tag: duct, duct noise, duct noise calculation, noise, sound, sound attenuation. 3 ÷ . The sound attenuators should have adequate silencing capabilities, low air resistance and be as small as possible. metres or feet). In this example , the following 1:1 octave bands have been measured: Frequency Hz 63 125 250 500 1000 2000 4000 8000. 4. Figure 1: Calculation of various load 1. 1. net Noise Mapping Tool is used for modelling external sound propagation and calculating sound levels using sources of noise and screening from barriers. A duct, shown in Fig. 2. The load impedance must be used in place of speaker impedance, and can be any value desired. Download 4 Types of Excel Calculator's. This excel sheet calculates the noise attenuation for air ducts in air conditioning and ventilation systems liked air ducts, VAV boxes, air terminals (diffusers), etc. d 2 = m = ft. Application of sound attenuator DZ-3 DZ-3 sound attenuators are suitable to attenuate industrial machinery noises and for special applications in the air-conditi-oning engineering. Sound - Attenuation and the Directivity. Also it enables designers to design sound attenuation for masonry wall rooms. Air Terminals Selection Tool - for HVAC Engineers & Designers. Read More. The representative discussed this project with the mechanical engineering firm and acoustical consultant. In this example,sound attenuator calculation sound attenuator pressure drop calculation Selection of quieter equipment can eliminate many noise problems before they even begin. By: Moustafa M. Duct Noise Calculation Excel Sheet – Sound Attenuation. Related Documents SIL - the Speech. Bends provide attenuation as shown in Tables 3a and 3b. Using the options below, select your build up to get your acoustic calculation. sound attenuator calculation excel Nov 28, 2020 — Free character models c4d · Sound attenuator calculation excel · Fancy dj taj remix. NF EN ISO 9613-2 Acoustics -- Attenuation of sound during propagation outdoors -- Part 2: General method of. Microstrip Characteristic Impedance Calculator Using a Formula by Brian C Wadell Used for calculating the Zo of PCB transmission lines, showing the formula used. It allows entry of any manufacturer’s sound power level data as well as any manufacture’s equipment sound level used in the system. A power level of x space dB x dB is in linear scale. xml ¢ ( ¬UËNë0 Ý#ñ ‘·¨q¹ „PÓ. T = 1 / (500 Hz) = 0. Fans Static Head Calculation Sheet - Free download as Excel Spreadsheet (. for HVAC Systems. Install the sound attenuators in line with ductwork as per approved drawings. In order to further optimize the sound attenuator with regard to pressure drop, a part of the sound attenuator’s active section has been arranged outside the connection. LOAD ESTIMATE SHEET. Sound level calculation To calculate the relevant sound level the attenuator sound reduction must be substracted from the fan sound level. Another application of Helmholtz resonance is in the exhausts of vehicles: creating a suitably sized exhaust. Airlfow regenerated noise 3. Attenuation. It covers the features, benefits, and specifications of various types of silencers, including Conic-Flow® Tubular Silencers and D-Duct Acoustic Diffuser Silencers. For noise-sensitive applications, the intake and discharge attenuators can be as long as 10 ft to achieve the required level of attenuation. As a result, you may choose from a selection of “made-to-order” engineered duct silencers that will satisfy the requirements of each application. This excel sheet calculates the noise attenuation for air ducts in air conditioning and ventilation systems like air ducts, VAV boxes, air terminals (diffusers), etc. You have to create then an excel sheet for price calculation. Facebook Page : on twitter: : Attenuator. For instance, dark glasses attenuate sunlight, lead attenuates X. A noise calculator tool - This is an Excel spreadsheet that calculates the spot noise and integrated noise over a user specified bandwidth for inverting, non-inverting and transimpedance topology op amp circuits. a Absorption coefficient. Heat load calculation formula australia. If you have Catalog Sound Power data, you must. Start Now. Set the attenuation to 40 dB in the second box of the calculator. The Fantom IQ™ utilizes the patent pending FAST™ attenuator system that greatly reduces radiated sound power levels. We offer rectangular sound attenuators in high (type SA), medium (type MA) and low (type LA) pressure drop configurations. 35 dB/m) = 3. We would like to show you a description here but the site won’t allow us. R1 = Distance from the noise source to. This complimentary service is led by Vibro-Acoustics’ HVAC aerodynamic and acoustic engineering experts. 1 31. 26-19952. Calculate a list of mixer spurious responses for a set frequency plan. The human perception of loudness is perceived differently fromsound attenuation spreadsheet rev. The distance from person 1 to bus stand is RΓéü = 10 m. Create your website today. 331. As an extension to your design team, we identify noise-related risk and recommend the best solution for the system. R = (12. Duct Noise Calculation Excel Sheet - Sound Attenuation. Calculate Back Pressure (in H2O) Temp (F) CFM CALCULATION OF BACK PRESSURE OF SILENCER Introduce Max. They offer very low loss (low value of alpha-attenuation). Fire Suppression Calculation Software Sheet - FirePro. The formula to calculate sound attenuation over a distance for a line source is: Lp (R2) = Lp (R1) - 10·Log10(R2/R1) Where: Lp (R1) = Known sound pressure level at the first location (typically measured data or equipment vendor data) Lp (R2) = Unknown sound pressure level at the second location. Support & Software Software ProSilencer ProSilencer Software for sound attenuator selection. SNR Hearing Protector Method. Approximate attenuation per metre run is shown in Table 2. NO. This CRTN calculator is designed for a simple scenario containing one road segment in order to calculate the Basic Noise Level from the traffic flow, traffic speed and percentage of heavy goods. are subtracted. How to calculate heat load for a house. Download Free Arabic and Kufi SHX AutoCAD Fonts. (Circular or Rectangular) Table 3a: The attenuation of mitred bends with short chord turning vanes or no turning vanes. Noise and Attenuation Noise is usually defined as unwanted sound - noise, noise generation, silencers and attenuation in HVAC systems. 3 The Software: E 20 Excel Sheet E 20 excel sheet is a computer tool produced by Excel, a company providing solution for heating, air conditioning and refrigeration. Furthermore, for power, SNR = 20 log (S ÷ N) and for voltage, SNR = 10 log (S ÷ N). Categories. Sound Attenuators for HVAC Industry. Its available to use on all versions of Microsoft Windows. 100 Watt power attenuator. 145145. Sound Power and Sound Pressure are different in that Sound. Sound Power from Sound Pressure. Oct 2, 2012 — Sound attenuator calculation excel · Drakor id tv · Association franco vietnamienne nimes · Free moorish american · Babymetal legend s setlist. Our WorkshopsResult: Free Space Path Loss (FSPL) calculations are often used to help predict RF signal strength in an antenna system. R1 = Distance from the noise source to location. Get Technical Help. This test standard describes methods that may be applied to calculate the sound power level of fans. 6log10 RPM Source: Bies and Hansen. This excel sheet calculates the noise. Noise Any unwanted sound or meaningless sound of greater than usual volume. Use our resources below to find more cost-effective ways to improve your STC Rating, or use the STC Calculator to determine alternate wall designs. L-pad Attenuator. In analyzing sound propagation in ducts it is customary to simplify the problem into one having only two dimensions. Project: Calculation By: Ductwork Static Pressure Calculation Length (ft) BCIT MSYS 4480 Energy Savings Calculator (HePESC)”, which provides comprehensive energy use and cost savings estimations for a variety of heat pump technologies. Save Save Louver Selection Calculation. L. It has. Sponsored Links. Add Safety factors Add safety factors - 3 dB is recommended. Call Us +961 1 898268. 6 Fire damper 0. Note that speed is a. The sound attenuation in 10 m duct is. In this study, the acoustical simulation of a large diesel generator set with an enclosure by finite element method (FEM) is presented. array to be placed as much as four times farther from the sound source. Download also: HVAC Systems Noise both Vibration Isolation Book . Engineering Noise Control (4th Edition) Theory and Practice. (See ASHRAE’s “System Design Procedures”1 for more details. Produces attenuator schedules in easy-to-use formats in Excel & PDF. And the brand name. The sound wave generated by these sources transfer its energy throughout the duct and to the occupant’s area as shown below.