Selecting High Plume Dilution Fans

What to Consider When Selecting Fans For Your Application

When selecting a fan, I prefer to do so in a deductive fashion. In other words, try to understand everything you possibly can about the nature of the application and the details about what the fan is going to be doing. From there, you can actually use a process of elimination to back right into the appropriate types of fans.

1. Ventilation vs. Process or Ducted

You have several types of fans to choose from—such as axial, centrifugal, or mixed flow—but I think the first and best way to approach the task is to pay attention to the two general types of applications for industrial/commercial applications: ventilation or process/ducted. With general ventilation, the fan accelerates air and moves it from one side of an enclosure to another (like through a wall or roof).

With process or ducted applications, the fans are typically mounted in ducts or have other pertinences in the system that provide back pressure against the fan. These pertinences could be fume scrubbers, mist eliminators, sound attenuators, energy transfer devices, etc. As the air is accelerated through those systems, there is a wide range of pressure that the fan has to overcome. These fans work in contained environments and develop higher pressures than general ventilation fans.

2. Mounting

Once you determine the nature of the application (general vs. process or ducted), you need to consider how the fan will be mounted. In a general ventilation application, it is usually mounted to the roof or the wall. In a process or ducted application, it is typically mounted on a roof or pad with the duct coming into or discharging from the fan (or ducted both inlet and outlet).

Both ventilation fans and process/ducted fans can be mounted in either horizontal airflow or vertical airflow orientations.

3. Performance & Accessibility Requirements

The initial trait to determine in terms of fan performance is how much flow and pressure development the fan must be capable of generating. On the process or ducted type, there will typically be a broader range of pressure development requirements, depending on the nature of the system.

In terms of accessibility, where are you going to mount the fan, and how are you going to be able to access it for inspection, periodic maintenance, or replacement (if that ever becomes required)? What is the temperature and density of the air? These factors, along with the performance requirements, will affect the fan construction and fan material, as well as help you to determine whether it is best to have a direct or belt drive fan.

4. Noise Level, Efficiency, & Redundancy Requirements

Noise levels generated by the fan and efficiency are often considerations for selecting an appropriate fan. If low noise and high efficiency are required, it will have a significant impact on the size and type of fan that you will select.

You also need to think about whether the system is constant flow constant volume or variable volume and if you have a critical service system where redundancy is required in the fan equipment.

These traits need to be known in order to help optimize fan selection to satisfy your requirements. If you would like assistance with the selection process, contact us today.

Related Blogposts:

High Plume Dilution Fans – Now with Composite Plenums

Featured Manufacturer:
MK Plastics is the leading manufacturer of corrosion resistant industrial and commercial blowers, fans, and  ventilation systems. Patented in several countries, products are AMCA Certified for Air and Sound Performance

For More Information - askRick


ASHRAE’s Building Energy Quotient in Operation

Announcing New Building EQ Portal
ASHRAE In Operation Rating

ASHRAE’s Building Energy Quotient (Building EQ) In Operation rating program provides a quick energy analysis that compares your building to similar buildings within the same climate, helps to identify means to improve your building’s energy performance, and provides data on Indoor Environmental Quality.

Two different evaluations can be used independently to compare a candidate building to other similar buildings in the same climate zone or together for an assessment of a building’s design potential compared to actual operation:

Now Available
In Operation compares actual building energy use based on metered energy information.

Coming Soon
As Designed compares potential energy use based on the building’s physical characteristics
and systems with standardized energy use simulation.

Building EQ Portal is the most comprehensive assessment platform providing actionable recommendations for today’s commercial and institutional buildings.

Features include:

• Online data entry and submission process
• Metered energy data exchange from ENERGY STAR™ Portfolio Manager
• Median EUI calculation aligned with ENERGY STAR™
• Building EQ Performance Score visible to all users on the main input screen at all times
• Redesigned label shows Building EQ Performance Score on a barometer/scale.
No more letter grades!
• Standard reports can be automatically generated by credentialed users
• Improved submission approval process
• Help and validation information is built into the system

Visit for more information.

Related Blogposts:

For More Information - askRick


High Plume Dilution Fans | Now with Composite Plenums

K-Kore™ Composite Air Plenums and Energy Recovery Plenums

The perfect product to provide years of trouble-free operation, K-Kore Composite Air Plenums and Energy Recovery Plenums use the latest technology in composite construction materials that renders steel construction obsolete. Our patent-pending Fiberglass Reinforced Plastic (FRP) assembly will provide the ultimate in durability and equipment life.

K-Kore plenums are high quality custom designed exhaust systems for commercial, industrial and institutional applications where corrosive environments can rapidly destroy steel equipment. The product is manufactured from high quality reinforced composites that can be engineered to withstand any corrosive environment, from the acidic rain or wastewater treatment plants of industrialized cities to the chemical exhausts of university or hospital laboratories.

Why Composites?

Composite materials, once considered futuristic and expensive, are now commonly used for all high-tech manufacturing sectors, from aerospace manufacturing to the automotive industry. Metal construction is considered obsolete in most high-tech industries where any degree of corrosion resistance or longevity is required, and so the engineers at MK Plastics came together with a common purpose of keeping the HVAC industry up to speed with the pace of technological advancements in material design.

Pound per pound, composite construction is stronger, more durable, and significantly more corrosion resistant than coated metal construction. The thermal conductivity is extremely low, allowing a true no-through metal design over the entire depth of the panel, something unachievable with current metal design.

Composite History

The use of resin-infused fiberglass for marine construction began over 50 years ago in the 1960’s. The actual service life of this material is unknown since there has never been a failure in the industry due to corrosion through exposure to saltwater environments. K-Kore plenum construction uses the same resin-infused fiberglass design that will almost certainly shown no signs of corrosion after 50+ years in the harshest environmental conditions. In the conceivable event that the K-Kore unit outlasts the building in which it is installed, the material can be recycled in an environmentally friendly manner.

Composite Usage

Composites are everywhere in the world today. Look up and you might see an airliner from Boeing, Airbus or Bombardier pass overhead, with their high-tech composite bodies allowing greater range, fuel economy and longevity compared to their metal rivals. Sports cars, military vehicles, spacecraft and almost all other high tech construction industries make extensive use of composite construction. The HVAC industry, until now, has been lagging far behind the state of the art. MK Plastics is bringing the construction industry into the 21st century.


  • Lightweight construction. Up to 40% weight savings vs. steel construction.
  • True no-thru-metal construction throughout the entire cabinet depth.
  • Unlimited salt-spray resistance: FRP has over 40 years (and counting) of salt spray exposure with no detrimental effects.
  • Corrosion resistance: K-Kore™ Air Plenums are the only products that carry a 50 year expected service life without corrosion in most environments.
  • Flame Spread index of less than 25 when tested according to UL 723.
  • Acoustic Performance: Tested and certified acoustic performance of the composite skins and cores allows the highest level of acoustic performance. Acoustic software accurately predicts the unit performance based on independently certified results from ASTM E 90 and ASTM C 423.


Contact us to learn more or visit the MK Plastics site to learn more.

Featured Manufacturer:
MK Plastics is the leading manufacturer of corrosion resistant industrial and commercial blowers, fans, and  ventilation systems. Patented in several countries, our products are AMCA Certified for Air and Sound Performance.

For More Information - askRick

Project Snapshot: Boston University – Theater Center

Project Name: Boston University – Theater Center
 Architect: Elkus Manfredi Architects
Mechanical Engineer: Vanderweil
Mechanical Contractor: TG Gallagher
Equipment: Modular Chiller and Boiler Plant – Mechanical Enclosure
Manufacturer: Cambridgeport 
Size: Two 125 ton chillers, three CW pumps, three CHW pumps,
two HW pumps, one FC pump, two boilers, all piping and accessories and a fully packaged control system with a refrigeration monitoring system.
DAC Sales Engineer: Matt Tefft

Project Overview

Boston University now boasts a state-of-the-art multi-functional 250-seat studio theater complex and production facility housing space for scenery, prop, and costume shops, as well as faculty offices, design labs and teaching spaces, therefore uniting the theater community by combining the previously separated design and production spaces with the theater and opera performance programs.

Continuing their established relationship with BOND, TG Gallagher was brought on the team to install the HVAC system in the new theater. At the heart of the theater is a modular chiller and boiler rental that houses two 125 ton chillers, three CW pumps, three CHW pumps, two HW pumps, one FC pump, two boilers, all piping and accessories and a fully packaged control system with a refrigeration monitoring system.  The entire chiller plant was prefabricated at TG Gallagher’s prefab facility and was rigged on site in four packaged sections.  Taking the initiative to prefabricate to such an extent allowed TG Gallagher to complete the entire mechanical room offsite in a controlled environment.  This approach improves safety and quality control, decreases waste and simplifies the project logistics.

Related Blog Posts:




Coils — Construction vs. Performance

Coils – Construction vs. Performance
(Credit to Guest Blogger: Matt Jacobs, Capital Coil & Air)

If you have ever dealt with commercial HVAC coils, you have probably come across numerous “industry terms” with little to no explanation as to what these terms actually mean. To further confuse you, some verbiage is specific to the actual construction of the coil, while others are only important when determining a coil’s performance. If you do not work with coils on a frequent basis, it is hard to decipher exactly what these terms are referring to. To help translate this industry verbiage, Capital Coil & Air has come up with a list/glossary of the most common and relevant terms that you are likely to come across on most coil jobs.


  • AHRI (Air-Conditioning, Heating, and Refrigeration Institute): Developed industry standards for air conditioning, heating, and commercial refrigeration equipment. All of CCA’s coils are AHRI-certified, so you know you’re getting dependable quality and performance in every product.
  • Air Pressure Drop: Air Pressure Drop is a result of Flow Rate, Fin Type, Rows and Fins per Inch. In addition, on either Chilled Water or  DX (Evaporator) Coils, the air pressure drop is affected by the condensate on the fin surface.
  • Airflow (CFM): Cubic Feet per Minute, which refers to the amount of air flowing across the coil. A typical cooling coil should produce between 400-500 FPM. You want to avoid exceeding 550 FPM on all Chilled Water & DX Coils. Too little airflow means your coil is not running at peak capacity, while too much airflow can result in excess water carryover.


  • Casing Type: The supporting metal structure for tubes and the header. Different casing options include Flanged (standard), Slip & Drive, Inverted, Stackable, and Collared End Plates & End Plates only. Steam Coils require Pitched Casing to allow for adequate condensation drainage.
  • Casing Material: The coil’s casing can be made from a variety of different materials. Options include: 14 or 16 Gauge, Galvanized Steel; 304 or 316 Stainless Steel; Copper & Aluminum. Please contact us directly to see about options other than those listed.
  • Connection Material/Type: Standard connection types are MPT (Male Pipe Thread, threaded on the outside), FPT (Female Pipe Thread, threaded on the inside), ODS (Sweat Connections, no threads)


Related Blogposts:
Cooling Coils and Moisture Carryover

Featured Manufacturer:
Capital Coil and Air is the leading manufacturer of commercial OEM HVAC replacement and custom design/build booster coils, fan coils, condenser coils, and DX Coils.
For More Information - askRick



SMARDT Chillers win Energy Award at Citizens Bank Data Center, Medford MA

Citizen Bank Data Center, Medford, Massachusetts

SMARDT, Danfoss Turbocor & Southern Air Win Association of Energy Engineers Award for Citizens Bank Installation

The New England Chapter of the Association of Energy Engineers (AEE) recently announced its 2007 Energy Awards Projects. Among the award winners were Southern Air and Citizens Bank for the Citizens Bank data center project in Medford, Massachusetts.

The project achieved multiple goals including:

1) An enticing electric utility rate being available if the data center could be switched over to in-house emergency generator power controlled by the utility company during peak demand periods.
2) The customer wanted to be able to lower condenser water temperatures under light load conditions, to significantly reduce energy consumption.
3) By reducing overall energy consumption, the owner would realize financial benefits of utility rebates and reduced electric power costs, and thereby offset the project cost.

  • Benefits:
  • Improved Energy
  • Efficiency
  • Superior Energy Savings
  • Reduced Operating Costs
  • Reduced Environmental Impact
  • Built In Redundancy
  • Total Cost of Ownership

The facility’s existing chillers were replaced with two 90 ton SMARDT brand chillers that utilize Turbocor oil-free, variable speed, centrifugal compressors. Because Turbocor compressors draw less than 2 amps at startup (rather than a typical in-rush current of 300-400 amps), they are very compatible with the emergency generator application. No in-rush current greatly reduced the generator capacity that would otherwise be needed. Furthermore, the oil-free compressor design enhances operation at the lower condensing pressures that can be achieved as oil return is no longer an issue. This provides extremely efficient operation at low load conditions, where the chillers will operate most of the time.

Featured Manufacturers:
SMARDT specializing in using Turbocor compressors in its full line of water and air cooled chillers for commercial and industrial applications.

For More Information - askRick




Our Process: HVAC Solutions Designed Around You

Rick McGinley

Rick McGinley VP of Engineering

We’re Different:  Your DAC Sales Engineer designs your system, executes the CAD work, coordinates the bidding process, and takes personal responsibility for your job from start to finish. No other firm offers this level of continuity, and it gives our customers a lot more confidence. No matter where you are in the process, we don’t shuttle you between departments. We don’t miss calls or information or opportunities.  Our whole team is behind you, but your DAC Sales Engineer is always right beside you.

We believe in a better process:  At DAC Sales, the process of the air conditioning repair is as important as the finished product. Our nationally recognized design team believes every HVAC system design should be a custom HVAC system design. We make your system a perfect fit for your building, your budget and your priorities. When you work with DAC Sales, you do a lot of talking and we do a lot of listening. Our engineers bring an average of 16 years of experience, creativity, and hands-on expertise to every project. We never forget that the most important person at the drafting table or on the job is you. DAC Sales led the way on sustainability and energy efficiency, and our design process makes environmental impact and energy savings a top priority. Any HVAC system designed by DAC Sales has sustainability and energy efficiency in its DNA. As we design your sustainable, energy efficient HVAC application, we provide you with detailed drawings, personalized equipment selections, energy payback analyses and timely cost projections. Have questions or concerns? You will always know just who to call – your personal DAC Sales Engineer.
We’re here for you. Give us a call:

DAC Sales Engineer Email Address Cell Phone
Craig Ashman 207-604-0894
Brad Carpenter 508-713-7042
Rich Clarke 401-528-7992
David Goodman 508-423-0088
Rick McGinley 207-232-4675
Dan Swanson 781-405-4144
Matt Tefft 617-913-3874
Pat Will 207-415-6861
For More Information - askRick



Project Snapshot: Freetown Lakeville Intermediate School | Pool Unit

Project Name: Freetown-Lakeville Intermediate School
 Architect: Architectural Resources Cambridge, Inc.
Mechanical Engineer: SED Associates
Mechanical Contractor: Ambient Temperature, Inc..
Equipment: Pool Dehumidifier
Manufacturer: Seresco
Size: Seresco NP-18 Pool Dehumidification Unit.
DAC Sales Engineer: Craig Ashman

Project Overview:

In 1994, Rick McGinley from DAC Sales designed an air-to-air dehumidification unit for the George R. Austin Intermediate School (Freetown-Lakeville Intermediate School).  The unit was supplied by Des Champs and was state of the art, for the time.  It utilized two air-to-air plate exchangers, a modulating re-circulation, and outside air dampers to regulate the outside air volume to the precise amount required for humidity control. This unit conveniently provided minimum outside air flow at the time when heating costs would be highest. Code ventilation rates were still maintained with a minimum set point on the dampers.


In 2016 Craig Ashman, DAC Sales Engineer, was contacted by SED Associates of Boston to discuss the replacement of this original unit.  The replacement would have to be accomplished with minimal disruption to existing structure and operations.  If possible, existing duct work and roof curbs were considered to make the transition smoother.


It was determined that the most cost effective piece of equipment, both first cost and operating cost, was the Seresco 18 ton Protocol Series unit.  A custom roof curb adapter was also designed and furnished to accommodate unit mounting.

Roof Curb Adapter

Glycol Cooled A/C by a Fluid Cooler–  About 40% of the units Seresco provides use fluid coolers in lieu of Refrigerant Based ACCU’s.  This is a standard product offering in their Protocol Line of Pool Dehumidification Units.  In the Pool Dehumidification Unit, Seresco provides a heat exchanger and a pumping package. In the heat exchanger, the refrigerant loop dumps the rejected heat to a glycol loop. It is then pumped to the Fluid Cooler on the roof. Piping is PVC from the Pool Dehumidification Unit to the Fluid Cooler. The Fluid Cooler distance can be nearly anything (600 feet is not a problem).

WebSentry –  This application was also equipped with WebSentry, Seresco’s online monitoring, reporting and service optimization tool.  The 24-7 WebSentry monitoring then allows Seresco to remotely monitor over 100 performance parameters of the dehumidifier using sophisticated algorithms to analyze and identify potential issues and maintenance requirements long before they become potential problems.

Design Advantages: There are many reasons why this type of application makes a lot of sense.  The ultimate is stable indoor air conditions through fully modulating reheat.

    • Up to 85% less refrigerant charge – completely factory sealed
      – Compliant with ASHRAE Standards 15 and 34
      – Less refrigerant means LEEDS points
      – Less cost to install and maintain
    • Eliminates all seasonal refrigeration and oil migration issues to outdoor condenser
      – Decreased risk of compressor issues
      – Increased performance
      – Lower maintenance costs
    • Air cooled AC heat exchanger can be located far from unit
      – Heat exchanger uses PVC instead of copper
      – Simple installation with lower cost of materials and labour
    • 5% to 7% more energy efficient than DX systems
    • WebSentry® Internet monitoring and control
    • Touch screen CommandCenter® control systems
    • Premium corrosion resistance
    • Mechanical vestibule outside the air stream on all units
      – more efficient operation
      – easy to service
      – protects key components from moisture and chemicals in the air stream

    To check for updates on the GRAIS pool, visit the district website at

For More Information - askRick




ECM Fan Array – vs. 3 Phase Motor & VFD

We are using more and more ECM Motors and Fans in our applications (both new equipment and retrofit).  There are a lot of good reasons to consider them in your ac designs.  Below is a side by side comparison and seven good reasons to use ECM Motors and Fans.

ECM Fan Array

ECM Fan Array

Fan with VFD array

Fan with VFD Array






  • Permanent Magnets in Rotor
  • Squirrel Cage Rotor
  •  No Slip Losses
  •  Slip Losses in Rotor
  •  Higher Efficiency and Performance
  •  Motor Temperature Rise
  • Precise Motor Speed Control/
    Exact Feedback from the Motor
  •  Motor speed not well defined
  • Matched System of Drive & Motor
    /Easy to Install
  •  Parameter Setting of VFD/
  • Complicated Installation

High Efficiency:  A big advantage of ECM motors is that they are significantly more efficient when compared to AC motors.  ECM motors maintain a high level (65 to 75 percent) of efficiency at a variety of speeds.   This is not true for AC motors operated on variable frequency drives. As a result, ECMs are cost and energy efficient and can reduce operating costs.  In most cases, they use from less than one third to one half of the electricity used by traditional induction motors used in HVAC applications.

Ease of Control:  ECMs are DC motors that function using a built-in inverter and a magnet rotor (no external VFD).  The motor’s operation is simply controlled by software allowing customers to optimize and integrate the motor, fan and controller with the application.  Features like data communications, constant volume control and variable speed control are simple to integrate.

ECM Fan-2Low Operating Temperatures:  ECM motors’ high efficiency also means that the motors run “cool” and dramatically reduce the amount of waste heat produced.

Extended Life:  Motor life of the ECM is extended due to its low operating temperature operation.  ECMs are also relatively low-maintenance; the use of true ball bearings reduces the need for oiling, and varied start-up speeds reduce stress on mounting hardware.  Less components, less trouble.

Quiet Operation:  ECM motors are also quieter than traditional inefficient motors.

Wider Operating Range:  ECM motors also have a wider operating range than traditional induction motors which means that one ECM motor can replace a number of induction motor models. In this way, the number of models required by a typical customer is significantly decreased, which decreases and simplifies inventory.Standard vs. ECM Fans-1

Compact footprint:  ECM motors have a reduced footprint.  They provide a significant savings in design layout for units.

Related Blog Posts:  
Custom Air Handling Unit Design | The ECM Fan Array
Project Snapshot: WCCC UMass Data Center | Custom Air Handling Units

Featured Manufacturer:    Cambridgeport Custom Air Handling Units  using ECM motors and fans by EBM Pabst

Also see QPAC Fan Arrays for retrofit applications.

Call us for more information or a product demonstration on ECM Motors & Fans.



Large Refrigerant Charges – No More

Split DX pool dehumidifiers have huge refrigerant charges and that is an ugly liability for owners. There are solutions available today that completely make that liability go away. Montgomery County in MD was recently charged $100 per pound for R22. Imagine getting a bill for $10,000.00 to just recharge their 100 lb dehumidifier’s one circuit with refrigerant.  Ouch!

Effective January 1 2017, the Environmental Protection Agency (EPA) requires indoor pool owners/managers to formally track and document refrigerant leaks from commercial dehumidifier HVAC systems. Section 608 of the Clean Air Act mandates that when a leak occurs, owners must maintain records including the unit’s location, leak verification test dates, all repaired leak locations, type of verification test used and their results. The purpose is to verify whether a repair was successful and that the leak was addressed, according to an EPA spokesperson. The records must be kept on site in electronic or paper form for a minimum of three years.

In July of 2015 the EPA published a document outlining the phase out plan for all HFCs. R134A and R410A are HFCs.

SerescoIf a customer has an R22 system they are paying dearly anytime they have work done that implicates the refrigerant. Systems with large R410A charges are also expensive and will get worse. Systems being designed today will be implicated by the 410A phase out during their lifespan. It is essential to take steps today to reduce refrigerant related liabilities.

When the indoor pool industry has questions, they turn to Seresco for answers and guidance. We have already published two articles on this subject;  Refrigerant Issue Heats Up and Escalating Costs for Owners of Dehumidifiers Using R22 Refrigerant.

Why is all this important to you?

Because Seresco has the best solution for this issue – a product line that has the lowest refrigerant charges in the industry. No site refrigeration work needed. Reject heat outdoors through a dry cooler.

All Seresco units can be set up to reject heat outdoors to a dry cooler. The NP Series offers up to 85% less refrigerant charge than traditional split DX dehumidifier. This limits future liability on leaks and significantly reduces initial installation costs as well.

As the EPA continues to drive change in policy, Seresco will continue to bring the market products that support environmental stewardship goals while saving owners time and money.

Related Manufacturer:  Seresco
Related Documents:  NP Series Brochure
More information on the NP Series from Seresco.  

For More Information - askRick