Archive for the ‘FAQ’s’ Category
Is spiral ductwork more quiet than rectangular ductwork?
YES, ASHRAE says spiral is always more quiet than rectangular. See this table from 2011 ASHRAE Applications. WOW, a lot quieter!
What is Static Regain?
This design methodology sizes the supply duct system to obtain uniform static pressure at all branches and outlets. Much more complex than equal friction, static regain can be used to design systems of any pressure or velocity. Duct velocities are systematically reduced over the length of the distribution layout, which allows the velocity pressure to convert to static pressure, offseting friction losses in the succeeding section of duct. Systems designed using static regain require little ...
How long has static regain been used for ductwork design?
Static regain has been used since the 1940s and followed the development of the commercial fan and air moving market. Static regain is very friendly to long term operations but it took a lot of calculating, adjusting sizes and recalculating to get a system balanced on paper. With computer availability in the 1970s, static regain was done with a punch card input system. In the early 1980s, the IBM PCs were used to calculate DOS based ...
What is Equal Friction?
The Equal Friction design methodology sizes the supply duct system for a constant pressure loss per unit length such as 0.1"wg friction loss per 100 feet of duct. This is a low velocity industry standard. Equal Friction is the most widely used method of sizing lower pressure, lower velocity duct systems. There is no equalization of pressure drops in duct branches unless the system has a symmetrical layout. Dampers are used for balancing.
Does static regain actually save energy?
Most VAV ductwork systems are sized for a 1% ASHRAE cooling day for 86 hrs/year of peak demand. The average VAV fan system operates at 65-75% capacity for 4000 hours/year and operates at minimum 35% capacity for 2000 hrs/year. With static regain using 30% smaller VAV spiral duct sizes, there is less BHp-Hrs used for part load spiral systems estimated at 5-10% less than rectangular ductwork systems. Actual operating leakage savings using smaller spiral ducts ...
WHY LOOK AT STATIC REGAIN METHOD?
A local leadership enegry engineer explained that we need to do two important missions. "Stop wasting energy" is required. "Start saving energy" is desired. Static Regain methodology is more efficient with less lbs of supply ductwork, lower acoustic effect and less noise, and part load energy savings which are very important.
Lastest News
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Why using spiral duct improves duct design – SNIPS article
April 22, 2019
In 1948, research by R.G. Huebscher established flow resistance for different shapes of ductwork at equal velocities, which allowed the creation of the duct-sizing calculator or “Ductulator” for picking equivalent sizes of rectangular ducts based on the baseline round duct size. The Ductulator is a shortcut that only works on paper if you reduce the […]
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2014 was productive for Optimized Spiral using VariTRANE.
December 30, 2014
2014 was productive for Optimized Spiral using VariTRANE. A mechanical contractor in New Jersey used VariTRANE to save $80,000 cost on a 300T fitness center. A strategic partner in Utah used VariTRANE to save $70,000 cost on a 63,000 SF office building. A strategic partner in California used VariTRANE to save $60,000 cost on a […]
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SPECIAL… BRING IT ON!
July 27, 2012
Guaranteed: $20,000 in engineered spiral static regain savings for preparing a redline system design up to 34,000 SF or 100 tons, a value of $10,000. Included: a one-day static regain seminar at your location before December 14, 2015, Included: 12 months of support consultation by phone and email, a value of $10,000 a value of $7,500 a value of $2,500 Total value […]
- Trane Strategic Partner Exchange – 6 Real World Examples February 25, 2012
Featured Projects
1983 5 Story Office Building1983 5 Story Office: 82,000 SF 5 story with 175 tons DX RTUs using static regain spiral distribution to 145 VAVs. Static regain spiral installed at 18,000 lbs costing $116,700 in place of rectangular MP at 36,500 lbs costing $211,700 saving $95,000 or $1.16 per SF basis 2012$$.
