---
title: Using High-Induction Diffusers to Improve Air Quality
description: With the help of CFD, the Predict team used high-induction diffusers to obtain efficient ventilation with an overhead mixing system in a heating climate.
image: https://blog.priceindustries.com/hubfs/Fig.%201.%20CFD%20Classroom%20Model.png
---

![PriceTraining\_Logo\_RGB-1](https://blog.priceindustries.com/hs-fs/hubfs/PriceTraining_Logo_RGB-1.png?width=303&height=58&name=PriceTraining_Logo_RGB-1.png)

 

[![Price Industries](https://blog.priceindustries.com/hubfs/Priceindustries-March-2018/Images/Price_Logo_Blue.svg)](https://www.priceindustries.com/) The Science of ComfortTM

## The Science of Comfort

Your Premier Source for All Things HVAC

# Using High-Induction Diffusers to Improve Air Quality

Posted by [Mike Koupriyanov, P.Eng.](https://blog.priceindustries.com/author/mike-koupriyanov) on September 27, 2022 at 9:18 AM

![Mike Koupriyanov, P.Eng.](https://blog.priceindustries.com/hubfs/MikeK_HS2.png)

Find me on:

[LinkedIn](https://www.linkedin.com/in/mike-koupriyanov-45849b6b)

- [Tweet](https://twitter.com/share)

## A CFD Classroom Case Study

Obtaining efficient ventilation with overhead mixing systems for applications in heating climates can be a challenge. Not only does the positive buoyancy of the supply air work against the air distribution system, but most overhead mixing systems are designed with low supply air volumes (relative to cooling) and high supply air temperatures (more than 15°F above room temperature). This combination leads to unfavorable thermal stratification and a low zone air distribution effectiveness in the winter months. Air distribution effectiveness, as defined in [*ASHRAE Standard 62.1*](https://www.ashrae.org/technical-resources/bookstore/standards-62-1-62-2), measures how effectively a system delivers ventilation air into the breathing zone.

Although there are many strategies for addressing these issues, using high-induction ceiling diffusers, such as square swirl diffusers, is a cost-effective option since they work with existing designs and installation practices.

A high-induction diffuser discharges a swirling air pattern parallel to the ceiling, which reduces the throw of a diffuser (compared to a traditional mixing diffuser at the same airflow) and induces more room air up to the ceiling, thereby increasing mixing in the occupied zone. This reduces the thermal stratification in the space and produces a higher zone air distribution effectiveness compared to that of more traditional mixing diffusers.

[Price’s Predict team](https://predictcfd.com/) recently vetted the application of these diffusers for a new primary school project in Quebec. The team created a computational fluid dynamics (CFD) model of a typical 567 square foot classroom in the school to analyze the effectiveness of the air distribution system in heating mode.

The initial design (shown in figure 1) consisted of two swirl diffusers in addition to standard slot diffusers next to the windows.

| ![Fig. 1. CFD classroom model of the initial design](https://blog.priceindustries.com/hs-fs/hubfs/Fig.%201.%20CFD%20Classroom%20Model.png?width=512&name=Fig.%201.%20CFD%20Classroom%20Model.png) |
| --- |
| Figure 1. The Predict team’s classroom CFD model, including two high-induction diffusers ([Price’s Radial Slot Diffuser](https://www.priceindustries.com/diffusers/products/radial-slot-diffuser) pictured) |

The CFD results for the initial design showed high thermal stratification in the space (illustrated in figure 2) and low zone air distribution effectiveness at the seated breathing zone.

| ![Fig. 2. Temperature illustration of the initial design](https://blog.priceindustries.com/hs-fs/hubfs/Fig.%202.%20Temp%20initial%20design.jpg?width=2400&name=Fig.%202.%20Temp%20initial%20design.jpg) |
| --- |
| Figure 2. The temperature profile of the initial design with overlaid velocity vectors |

Looking at the air patterns in figure 3, we can see that although the system generated air move¬ment down to the occupied zone, it was not enough to adequately mix the warm supply air into the occupied zone.

| ![Fig. 3. Velocity illustration of the initial design](https://blog.priceindustries.com/hs-fs/hubfs/Fig.%203.%20Velocity%20initial%20design.jpg?width=2400&name=Fig.%203.%20Velocity%20initial%20design.jpg) |
| --- |
| Figure 3. The velocity profile of the initial design with overlaid velocity vectors |

The team’s final design omitted the slot diffusers, allowing the extra air volume to be shifted to the swirl diffusers, which were repositioned to further optimize mixing.

The results for this optimized design showed a much more uniform temperature distribution in the classroom (figure 4) with better comfort, lower thermal stratification and a significantly higher zone air distribution effectiveness.

| ![Fig. 4. Temperature illustration of the optimized design](https://blog.priceindustries.com/hs-fs/hubfs/Fig.%204.%20Temp%20optimized%20design.jpg?width=1407&name=Fig.%204.%20Temp%20optimized%20design.jpg) |
| --- |
| Figure 4. The temperature profile of the optimized design with overlaid velocity vectors |

If we look at figure 5 and compare it to figure 3, we can see why this is the case. The placement of the diffusers combined with the extra airflow in the optimized design creates more air movement and allows the supply air to penetrate further down into the occupied zone.

| ![Fig. 5. Velocity illustration of tthe optimized design](https://blog.priceindustries.com/hs-fs/hubfs/Fig.%205.%20Velocity%20optimized%20design.jpg?width=1410&name=Fig.%205.%20Velocity%20optimized%20design.jpg) |
| --- |
| Figure 5. The velocity profile of the optimized design with overlaid velocity vectors |

This study highlights not only the effectiveness of swirl diffusers for heating climates but also the [importance of using a CFD analysis](https://blog.priceindustries.com/using-computational-fluid-dynamics-to-optimize-hvac-design) to achieve their intended performance in the real world. To learn more about CFD and how a CFD analysis can optimize your next project, email us at [info@predictCFD.com](mailto:info@predictCFD.com).

[![Predict by Price](https://no-cache.hubspot.com/cta/default/4024064/8320cdda-6d65-47a3-b099-26bda0fdb4b9.png)](https://cta-redirect.hubspot.com/cta/redirect/4024064/8320cdda-6d65-47a3-b099-26bda0fdb4b9)

 

 Topics: [GRD](https://blog.priceindustries.com/tag/grd), [Diffusers](https://blog.priceindustries.com/tag/diffusers), [HVAC](https://blog.priceindustries.com/tag/hvac), [Engineering](https://blog.priceindustries.com/tag/engineering), [Design Engineering](https://blog.priceindustries.com/tag/design-engineering), [ASHRAE 62](https://blog.priceindustries.com/tag/ashrae-62), [CFD](https://blog.priceindustries.com/tag/cfd)

## At Price, when we say “the sky is the limit,” we actually mean it.

Our customers have come to count on a consistent and ever-increasing stream of new products and enhancements.  Price has a large team of experienced and talented engineers who are consistently working on breakthrough ideas.  We are not afraid to move into whole new product categories if we believe we have a contribution to make.

- Research & Innovation
- Technical Tours
- Training Classes
- Targeted Discussions
- Mock-up Testing
- Custom Solutions & Specials
- Custom Finishes
- Computational Fluid Dynamics
- Virtual Reality

### Subscribe to Email Updates

### Recent Posts

### Posts by Topic

- [HVAC (148)](https://blog.priceindustries.com/tag/hvac)
- [Engineering (122)](https://blog.priceindustries.com/tag/engineering)
- [Design Engineering (106)](https://blog.priceindustries.com/tag/design-engineering)
- [HVAC Fundamentals (84)](https://blog.priceindustries.com/tag/hvac-fundamentals)
- [Employees (38)](https://blog.priceindustries.com/tag/employees)
- [Diffusers (32)](https://blog.priceindustries.com/tag/diffusers)
- [Thermal Comfort (32)](https://blog.priceindustries.com/tag/thermal-comfort)
- [Terminals (28)](https://blog.priceindustries.com/tag/terminals)
- [GRD (27)](https://blog.priceindustries.com/tag/grd)
- [Tech Tip (26)](https://blog.priceindustries.com/tag/tech-tip)
- [Critical Environments (23)](https://blog.priceindustries.com/tag/critical-environments)
- [Fan Coils (19)](https://blog.priceindustries.com/tag/fan-coils)
- [People of Price (19)](https://blog.priceindustries.com/tag/people-of-price)
- [Beams (17)](https://blog.priceindustries.com/tag/beams)
- [Customer Service (16)](https://blog.priceindustries.com/tag/customer-service)
- [Displacement (15)](https://blog.priceindustries.com/tag/displacement)
- [Architecture (14)](https://blog.priceindustries.com/tag/architecture)
- [Noise Control (14)](https://blog.priceindustries.com/tag/noise-control)
- [Pressure Drop (14)](https://blog.priceindustries.com/tag/pressure-drop)
- [13 Tenets (13)](https://blog.priceindustries.com/tag/13-tenets)
- [CFD (13)](https://blog.priceindustries.com/tag/cfd)
- [Filtration (13)](https://blog.priceindustries.com/tag/filtration)
- [System Efficiency (13)](https://blog.priceindustries.com/tag/system-efficiency)
- [Controls (12)](https://blog.priceindustries.com/tag/controls)
- [Training (12)](https://blog.priceindustries.com/tag/training)
- [Contractors (11)](https://blog.priceindustries.com/tag/contractors)
- [Grilles (11)](https://blog.priceindustries.com/tag/grilles)
- [Static Pressure (10)](https://blog.priceindustries.com/tag/static-pressure)
- [Engineering Update (9)](https://blog.priceindustries.com/tag/engineering-update)
- [Underfloor (9)](https://blog.priceindustries.com/tag/underfloor)
- [ASHRAE 170 (8)](https://blog.priceindustries.com/tag/ashrae-170)
- [ASHRAE 62 (7)](https://blog.priceindustries.com/tag/ashrae-62)
- [Acoustics (7)](https://blog.priceindustries.com/tag/acoustics)
- [Mock-Up (7)](https://blog.priceindustries.com/tag/mock-up)
- [VAV Diffusers (7)](https://blog.priceindustries.com/tag/vav-diffusers)
- [Heat Transfer (6)](https://blog.priceindustries.com/tag/heat-transfer)
- [Psychrometrics (6)](https://blog.priceindustries.com/tag/psychrometrics)
- [Tours (6)](https://blog.priceindustries.com/tag/tours)
- [Acoustic Panels (5)](https://blog.priceindustries.com/tag/acoustic-panels)
- [Giving (5)](https://blog.priceindustries.com/tag/giving)
- [HVAC Silencers (5)](https://blog.priceindustries.com/tag/hvac-silencers)
- [Philanthropy (5)](https://blog.priceindustries.com/tag/philanthropy)
- [ASHRAE (4)](https://blog.priceindustries.com/tag/ashrae)
- [Condensate (4)](https://blog.priceindustries.com/tag/condensate)
- [Handbook (4)](https://blog.priceindustries.com/tag/handbook)
- [Lighting (4)](https://blog.priceindustries.com/tag/lighting)
- [Noise Solution (4)](https://blog.priceindustries.com/tag/noise-solution)
- [Price Technical Center (4)](https://blog.priceindustries.com/tag/price-technical-center)
- [Cooling Coil (3)](https://blog.priceindustries.com/tag/cooling-coil)
- [Duct Noise Reduction (3)](https://blog.priceindustries.com/tag/duct-noise-reduction)
- [Events (3)](https://blog.priceindustries.com/tag/events)
- [Induction (3)](https://blog.priceindustries.com/tag/induction)
- [LEED for Schools (3)](https://blog.priceindustries.com/tag/leed-for-schools)
- [ASHRAE 70 (2)](https://blog.priceindustries.com/tag/ashrae-70)
- [Acoustic Louvers (2)](https://blog.priceindustries.com/tag/acoustic-louvers)
- [Background Noise (2)](https://blog.priceindustries.com/tag/background-noise)
- [Blower Coils (2)](https://blog.priceindustries.com/tag/blower-coils)
- [Catalog (2)](https://blog.priceindustries.com/tag/catalog)
- [Inlet Conditions (2)](https://blog.priceindustries.com/tag/inlet-conditions)
- [Inlet Effect (2)](https://blog.priceindustries.com/tag/inlet-effect)
- [Low Temperature (2)](https://blog.priceindustries.com/tag/low-temperature)
- [Noise Criteria (2)](https://blog.priceindustries.com/tag/noise-criteria)
- [Outlet Conditions (2)](https://blog.priceindustries.com/tag/outlet-conditions)
- [Price International (2)](https://blog.priceindustries.com/tag/price-international)
- [Reverberation Time (2)](https://blog.priceindustries.com/tag/reverberation-time)
- [Software (2)](https://blog.priceindustries.com/tag/software)
- [Sound Absorption (2)](https://blog.priceindustries.com/tag/sound-absorption)
- [Sound Masking (2)](https://blog.priceindustries.com/tag/sound-masking)
- [Speech Privacy (2)](https://blog.priceindustries.com/tag/speech-privacy)
- [Velocity Profile (2)](https://blog.priceindustries.com/tag/velocity-profile)
- [AROW (1)](https://blog.priceindustries.com/tag/arow)
- [Air Transfer Silencers (1)](https://blog.priceindustries.com/tag/air-transfer-silencers)
- [Ceiling Attenuation Class (1)](https://blog.priceindustries.com/tag/ceiling-attenuation-class)
- [LEED credits (1)](https://blog.priceindustries.com/tag/leed-credits)
- [LEED for Healthcare (1)](https://blog.priceindustries.com/tag/leed-for-healthcare)
- [Public Transit (1)](https://blog.priceindustries.com/tag/public-transit)
- [Sound Transmission Class (1)](https://blog.priceindustries.com/tag/sound-transmission-class)
- [Supply Chain (1)](https://blog.priceindustries.com/tag/supply-chain)
- [System Effect (1)](https://blog.priceindustries.com/tag/system-effect)
- [Transportation (1)](https://blog.priceindustries.com/tag/transportation)

see all

Follow us:

- [![Follow us on Twitter](https://blog.priceindustries.com/hubfs/Priceindustries-March-2018/Images/Twitter-icon.svg)](https://twitter.com/PriceHVAC)
- [![Subscribe to us on YouTube](https://blog.priceindustries.com/hubfs/Priceindustries-March-2018/Images/YouTube-icon.svg)](https://www.youtube.com/user/PriceHVAC)
- [![Follow us on LinkedIn](https://blog.priceindustries.com/hubfs/Priceindustries-March-2018/Images/LinkedIn-icon.svg)](https://www.linkedin.com/company/price-industries)

Have a question? [Contact Product Support](https://www.priceindustries.com/contact/product-support)

### Price Industries - Who We Are

The founding principles of Price have never changed – business integrity, first-class service, innovation and a commitment to people. Our dependable quality, reliable delivery, and knowledgeable follow-up service have made Price a market leader in supplying air distribution, critical controls, and noise control products. After more than 60 years, Price remains a privately held family company with a deep heritage and commitment to innovation and service. Our long-standing vision, traditional values, and the Price way of doing business are the cornerstones of our leadership position in the non-residential air distribution industry.

- - [Privacy Policy](https://www.priceindustries.com/legal/privacypolicy)
    - [Engineering E-Update](https://www.priceindustries.com/signup/newsletter)
- - [Contact Information](https://www.priceindustries.com/contact/reps-dealers?territory=International)
    - [Career Opportunities](https://www.priceindustries.com/corporate/careers)
    - [Our Services](https://www.priceindustries.com/services)

![Price Industries](https://blog.priceindustries.com/hubfs/Priceindustries-March-2018/Images/PriceLogo-footer.png) © 2018 Price Industries. All Rights Reserved. 2975 Shawnee Ridge Court - Suwanee, Georgia 30024 - (770) 623-8050.

- **Current Market:**
- [Canada](https://www.priceindustries.com/?SwitchMarket=Canada)
- [United States](https://www.priceindustries.com/?SwitchMarket=United%20States)
- [International](https://www.priceindustries.com/?SwitchMarket=International)