Duct system sizing to avoid obstructions enhanced equal friction duct system sizing to avoid obstructions simplified static regain coil psychrometrics. Air duct networks can be sized by using the equal friction, static regain. Static regain methodology sizes the supply duct system to obtain uniform static pressure at all branches and outlets. In sizing the duct, there may be a case where the trunk duct would get larger. Local pressure losses are caused by the fluid flow through the duct fittings. Static regain, equal friction, constant velocity, and as built presize. For air quantities greater than 4500 ls size duct at 10ms.
Re size noncritical paths to reduce system first cost while optimizing the system design. About duct sizing methods revit products 2018 autodesk. Duct sizing equal friction method engineering toolbox. In the duct sizing dialog, select a sizing method from the drop list. Pressure drop in the duct system can also be calculated.
Air duct networks can be sized by using the equal friction, static regain andor. Noise levels and required attenuation are printed for each runout duct. Much more complex than equal friction, static regain can be used to design systems of any pressure or velocity. You can use any method that you like, equal friction, or static regain. We will design spiral static regain to your choice of ext sp for maximum energy savings and optimum spiral sizing. Note that the size of the header duct a to b is the same for both equal friction and static regain method of duct sizing. We now go to the next step and design a duct system that will have a pressure drop of no more than the available static pressure. Design master hvac free download design master hvac 6 3d. Duct be used to design complete air conditioning systems including both supply and return ductwork for ventilation systems and complete exhaust systems for commercial, residential and industrial buildings.
Stretch your project dollars with static regain duct design trane. Elite software has a good cd on static regain, however i am only familier with these four. Calculate the pressure loss of the duct fitting in a 600mm w x 200mm h duct with. The equal friction and static regain methods used in revit use the ashrae duct. Static regain method for duct sizing can be effective in certain applications. The static regain method of duct sizing is based on bernoullis equation, which states that when a reduction of velocities takes place, a conversion of dynamic pressure into static pressure occurs. Existing duct sizing methods lawrence berkeley national. Duct design 2 available static pressure energy vanguard. Varitrane duct designer building energy software tools. System requirements for full functionality of all software programs, it is recommended that your system have at least the following configuration. Building load calculations are done using the ashrae. One example, the ductsize computer program developed by elite software.
With a smaller amount of air, the trunk duct may stay the same. High velocity static regain moves air with more efficieny compared to medium pressure rectangular supply ducts. We do it with software, but duct calculators give the same information. Much more complex than equal friction, static regain. The second problem centres around total pressure balancing. Normally, the size will decrease after a sizable tap to the terminal boxes.
The equal friction method for sizing air ducts is often preferred because it is quite easy to use. Ductwork sizing, calculation and design for efficiency the. Understanding basic residential ductwork design please note. Ductsize hvac duct sizing and analysis elite software. Revit doesnt have any builtin functionality to help size duct by static regain. Static pressure is the pressure that causes air in the duct to. The calculated duct sizes can be printed on a round, rectangular, and flat oval basis. Sizing ductwork using the static regain method results in small ducts and a system that is nearly balanced when first installed. Or, you can hire a contractor, and verify their working through duct sizing topic we were discussing a while ago. Calculate duct sizes based on equal friction, modified equal friction, static regain, or existing system. Duct system sizing to avoid obstructions simplified static regain. All information provided in this document is to be used as a guideline only. For this method, a section of the duct system is sized so that the increase in static pressure due to velocity reduction from its upstream.
Duct configurator helps you model and size supply duct systems, as well as determine required fan static pressures. Duct sizing calculations include constant pressure drop, constant velocity, and static regain. Duct sizing step by step with mcquay duct sizer duration. The static regain method claims to create equal static pressures at successive takeoff points along a main duct thereby causing equal air flow. The equal friction method creates an initial estimate for duct sizing based on the constant pressure loss per unit of duct length specified default is 0. More sophisticated than other duct sizing methods, rightcommduct will calculate the pressure needed to achieve the targeted friction rate, rather than manually readjusting the static. Yes revit can do static pressure loss calculations regardless of whether you size your duct using static regain, friction loss, or velocity. I have used static regain with a software program called dd4m. Static pressure is the outward push of air against duct surfaces and is a measure of resistance when air moves through an object like duct work. Upstream velocity of fitting h height of the duct w width of the duct r radius of the bend. It calculates both rectangular and round duct dimensions. As air is distributed off the main duct, the duct stays the same size, or actually increases in size. Elite software ductsize hvac duct sizing and analysis. Static regain improved this design methodology sizes the supply duct system to obtain uniform static pressure at all branches and outlets.
Software comprehensive collection of hvac design software and plumbing design software programs to help streamline and standardize your design process. A useful tool for finding duct diameter, duct velocity, friction loss and air mixture. The software is based on engineering data and procedures outlined in the ashrae fundamentals handbook. Duct system design guide first edition 2003 mcgill airflow corporation mcgill airflow corporation one mission park groveport, ohio 43125 duct system design i notice. Static regain methoda method of duct sizing in which duct velocities are systematically reduced, allowing a portion of the velocity pressure to convert to static pressure and offsetting duct friction losses velocity reduction methoda method of duct. Much more complex than equal friction, static regain can be used to. Static pressure regain a pragmatic solution to optimise the conflicting elements in duct design, the late w r roy ahern, offered the following approach1 for the sizing of lowpressure air conditioning ductwork. You can access this software free of charge by clicking here, and they offer a number of different account types depending on your simulation needs. Ductwork sizing, calculation and design for efficiency. To do that, we size ducts and choose fittings using something called equivalent length. You have to use good fittings and have a wellconnected system, but it is possible. Online ductulator duct size calculator ductcalc online. Links to 32bit versions of autodesk building systems 2006 and 2007, 32bit autocad mep 2008 to 2012 static regain version only.
A guide to the design of an effective low pressure vav air. Varitrane duct designer enables you to organize the layout structure of your duct system and provides detailed engineering information on a sectionbysection basis making revisions and updates easier. Compute the necessary air volume flow m 3 s, cfm in every room and branch of the system. Forgotten hvac software feature design master blog. Cfm and sizing calculations design master software. Latest updates on everything duct sizing software related. Ductulator calculats duct dimensions using equal friction method or velocity method. Use duct sizing revit products 2017 autodesk knowledge. It is clear that the static regain method simplifies the design process to a great extent. Air duct system design software, air conditioning systems, air flow calculations.
Comprehensive collection of hvac design software and plumbing design software. Velocity, friction, equal friction, or static regain. Duct sizing, duct calculation, duct design, energy efficient ductwork design. By sizing duct system for a constant pressure loss per unit length, such as 0. And it shows the velocity andor static pressure loss of air for both types of duct. Static regain methodology static regain methodology sizes the supply duct system to obtain. For those with access to a computer and the necessary software, a total pressure design of a system initially designed by static regain will produce the most. This is used as the major principle for sizing the ducts so that the increase in static pressure at each branch offsets the friction loss in the succeeding section of the duct. Determine the maximum acceptable airflow velocity in the main duct. The traditional duct sizing methods are equal friction and static regain ashrae, 2001. Whether you are a designbuild contractor, a building owner, or a consulting engineer, the varitrane duct designer software can put more money in your pocket. Static pressure loss by static regain method autodesk.
Hvac airside design package includes over 23 programs and forms that include. The equal friction method creates an initial guess for duct sizing by. This weeks topic answers the question, what is static regain. Based on the information given in table 3, select a starting velocity appropriate to the particular system and calculate the pressure loss in this first section of duct.
You can access this software free of charge by clicking here, and they. When you select friction or velocity, the following are activated. Problems with the static regain method sciencedirect. Duct sizing has been made easier by software that will calculate and route duct works within your building. This design methodology sizes the supply duct system to obtain uniform static pressure at all branches and outlets. Use 1 to compute the total air volume m 3 s, cfm in the main system. The elite software ductsize program quickly calculates optimal duct sizes using either the static regain, equal friction, or constant velocity method. This equalfriction method of duct sizing should be adequate for normal residential furnace heating and air conditioning applications. The same principle is utilized to provide equal pressures at the takeoff points of a duct riser that serves several floors which means that the duct sizing of each floor can be considered typical. And thats the subject of the next article in this series.
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