How do we best ensure sustainable indoor air quality and energy-efficient air handling?

Do we have to consume more energy to meet more stringent ventilation requirements?

We posed these questions to Erdem Kokgil and Johnnie Allan of Oxygen8, the Vancouver-based manufacturer of innovative heat and energy recovery ventilators.

We’ve designed our Coffee Break webinars to give you a unique insight into the latest HVAC technologies — ask your SVL Sales Engineer for an invite to our future sessions.

HRV vs. ERV

As a quick refresher, heat recovery ventilators (HRV) recover only sensible heat, with no change in moisture or humidity levels. Energy recovery ventilators (ERV) recover heat and moisture, decreasing OA temp and humidity in summer and increasing them in winter.

These devices are rated by their SRE (sensible recovery efficiency) performance. Wheel-based recovery devices have higher performance (70–90% SRE) but also have moving parts that cause problems and allow for a small amount of cross-contamination of airstreams. Fixed-plate exchangers (60–85% SRE) offer a low-maintenance alternative.

Wheels are primarily for high flow-rate applications (over 5,000 cfm), and fixed-plate devices are usually specified below that rate. However, new fixed-plate technologies, like those from Oxygen8, are viable for 5,000-10,000 cfm applications.

The Benefits of Sustainable IAQ

Our goal is to provide more fresh air into a building while decreasing the energy consumption it takes to accomplish that.

Scientists are developing more data about how buildings affect occupants’ cognitive functioning. It’s easy enough to meet ASHRAE ventilation minimums (usually 3–4 air changes per hour). However, according to the Harvard School of Public Health, the ideal target is 5–6 air changes per hour, twice the minimum.

A greater number of air changes brings down the levels of VOCs and CO₂ in building air and helps remove airborne particulate. This summer, there’s been much focus on removing PM2.5, the particulate in wildfire smoke.

Studies show that people display better cognitive functioning in buildings with better indoor air quality. They take fewer sick days per year and demonstrate a 2–10% increase in productivity in higher-ventilated spaces.

High-efficiency energy recovery is an ideal way to achieve this ventilation increase without spending vast sums on traditional increases in air changes per hour.

Oxygen8’s High-Efficiency Energy Recovery

Oxygen8 set out to deliver customizable ERVs, making them compact, quiet, and highly efficient. It only manufactures fixed-plate core devices in crossflow and counterflow models ranging from 300–10,000 cfm.

The company’s ventilators can be configured for Daikin VRV or hydronic integration.

It manufactures all its units in Vancouver, BC, including its cores and panels, to decrease lead times and have a more reliable supply chain.

Oxygen8’s devices recover up to 75% sensible heat with an ERV core and up to 85% with an HRV core. Their different models apply to different climates and buildings. In Minneapolis, there’s a sizable demand with schools for fixed plate cores and hydronic integration.

Counterflow heat exchangers are common in Europe and are becoming more common in America. These units are a bit longer than crossflow-type ERVs, which allows more space for more space for heat transfer.

Oxygen8 ERV cores use polymer membranes instead of the desiccants that you’ll find on wheels. These are designed so only heat and water vapor can pass through the membrane.

Plus, How to Comply with ASHRAE’s New Infectious Aerosols Standard

How can airstream ionization help solve the problem of poor-quality ventilation air? We sat down with Peter Eno from GPS, who described the company’s technology and its applications for viewers of our most recent Coffee Break webinar.

Ask your SVL sales engineer for an invite to our upcoming Coffee Breaks. In these 45-minute sessions, a subject-matter expert will explain all the nuances of a particular HVAC challenge or technology. Stay up to date and earn PDH credits in the process!

How does ionization lead to better IAQ?

The concept of airstream ionization has been explored for over 100 years. It had never gained much traction because older versions of the technology split the oxygen molecule and produced ozone.

The founder of GPS worked with these old ionization technologies before discovering that carbon fiber is an excellent conveyor of electricity and can produce ions without producing ozone. GPS has now developed technologies that effectively mitigate bad outdoor air and enhance a filter’s capabilities.

Outdoor air quality has been especially terrible during these last few summers of rampant wildfires across North America. But it’s not as if you can shut off your building to the outdoors without levels of CO2 increasing to unhealthy concentrations.

GPS products agglomerate particles in an airstream so filters can more easily remove them. The particles in wildfire smoke are smaller than 1 micron in diameter — so small that standard (non-MERV) filters have limited ability to remove them.

Introducing charged ions in the airstream will flocculate these tiny particles into groups large enough for effective filtration. This strategy similarly helps remove airborne pathogens and VOCs from the air.

What is ASHRAE’s guidance on removing viruses from your airstream?

ASHRAE 241: Control of Infectious Aerosols directly responds to the federal government asking for direction on IAQ concerns for when the next pandemic inevitably arrives. ASHRAE is a lynchpin in that conversation, and the government wanted ASHRAE to spell out exactly how building owners can move forward.

The standard establishes minimum requirements to reduce the risk of disease transmission through exposure to those aerosols in buildings. It becomes enforceable in January 2025 and will continue to evolve so that specifiers can make intelligent decisions about addressing this challenge for their building occupants. The standard explicitly mentions airstream ionization as one of the technologies that help remove these aerosols.

Remember that pathogens are particulate. Even VOCs, which are gasses, will host on a fine piece of particulate and ride the air current. When you agglomerate them, they are more easily removed. A molecule of virus is no different.

Are GPS products applicable to the IAQP in ASHRAE 62.1?

Yes! You can use more recirculated air when subjecting your return airstream to air cleaning procedures.

If your outdoor air load can be reduced credibly and safely, your architect will be thrilled — less tonnage, less electricity consumed, and less physical space to run extensive ductwork.

There are no downsides to ionization. It cleans the air, reduces outdoor air requirements, and makes building design more flexible.

If ionization groups particles together for easier filtration, is there a way to enhance the filter performance as well?

Opti-Lok from GPS is the solution you’re looking for. Standard filters come with an electrostatic charge that may last a few hours or weeks but will eventually dissipate. Opti-Lok imparts an electrostatic charge to whatever particles are coming into your filter.

Fine particulates, especially those in the sub-micron range, are a major component of wildfire smoke. GPS has run independent testing showing that Opti-Lok enhances a filter’s ability to remove these particles. This technology can improve a MERV 11 filter to MERV 13 performance.

Don’t choose between air quality and energy efficiency. enVerid explains how to get both from one technology.

We recently sat down with Matthew Gundrum from enVerid as he explained how the company’s Sorbent Ventilation Technology (SVT) is changing how engineers design air delivery systems.

If you want to learn more about the latest technologies in HVAC at our bimonthly Coffee Break webinars, ask your SVL sales engineer for an invite to our future sessions.

What is Sorbent Ventilation Technology?

SVT is an innovation that enables tonnage reduction in a building’s air-handling equipment. This advanced air-scrubbing technology fully complies with ASHRAE standards, in which its air-cleaning abilities reduce the amount of outdoor air a building needs to meet code.

A smaller outdoor air requirement means a smaller first cost for new construction by reducing the tonnage of the specified air handling equipment. This translates into ongoing savings in energy use reduction over the life of the building.

Besides these savings, SVT delivers great IAQ results for the building occupants. It helps builders qualify for LEED, WELL, and other green building certifications in the categories of air quality enhancements and energy reduction.

How does SVT work?

SVT is a filtration product. Sorbent is a gaseous media that uses adsorption to remove the contaminants generated in a space. It is a subtractive media that adds nothing to the airstream (no byproducts). Instead, it captures and sequesters contaminants. The sorbent media is packaged into a filter, and the filters are packaged in different fan-powered boxes. It can be integrated with various mechanical design schemes.

How does employing SVT reduce outdoor air requirements while still meeting code?

When contaminants are generated in a space, they enter the return airstream that is often ejected outdoors. This necessitates bringing in a high volume of outdoor air to replace that contaminated airstream, and conditioning outdoor air is a continual expense for building owners.

SVT reuses the return air you’ve already paid to condition by scrubbing that airstream of contaminants before it’s mixed with the new supply air and recirculated. In this strategy, ASHRAE gives you credit for cleaning the airstream and allows a reduction in the amount of new outdoor air you must bring into the AHU.

Which ASHRAE code does this refer to?

ASHRAE 62.1 defines this strategy, the Indoor Air Quality Procedure (IAQP), as a performance-based methodology that determines outdoor air requirements based on IAQ design targets and source-control and removal measures (like SVT).

IAQP results in equal or better IAQ than using 100% outdoor air (a strategy ASHRAE 62.1 calls the Ventilation Rate Procedure), especially when outdoor air is polluted or contains unusual contaminants. SVT is also fully compliant with International Mechanical Code.

How do the HVAC Load Reduction Modules work?

SVT may be deployed in a simple box with an ECM fan and a filter media core. In new construction or retrofits where RTUs are being replaced, SVT technology is available for integration into Daikin air handling equipment, requiring no new ductwork on the return side.

What are the best applications for SVT?

SVT is designed for spaces that use ASHRAE 62.1 to determine air changes and air quality, including offices, schools, commercial retail, event spaces, and other spaces prescriptively mentioned in that section.

This does not include spaces like critical healthcare settings with a mandated number of air changes per hour and anywhere with elevated exhaust needs, like commercial kitchens and laboratories, which require high volumes of makeup air.

Where can I learn more about SVT?

enVerid has over a thousand units installed and in design. This number is growing daily as more engineers learn that SVT is a great way to drive value for customers and be competitive in the marketplace.

Studies indicate that duct leakage is the most significant cause of inefficiency in commercial buildings. It costs building owners roughly $2.9 billion per year in increased energy consumption, on top of the many other problems that come with moisture intrusion in a duct system.

Luckily there are a few duct systems that better resist leakage. That’s why we recently held a Coffee Break webinar with Sterling Minter of Ducts and Cleats, a sheet metal fabricator in St. Paul, Minnesota, to discuss their Pro-R outdoor duct system.

Our Coffee Break series hosts the brightest minds in HVAC discussing the revolutionary technologies changing the industry. Ask your SVL sales engineer for an invite to our upcoming sessions.

The Problem with Standard Exterior Ducting

Standard external ductwork is notorious for its high rates of leakage. As weather conditions degrade the ductwork, air begins to leak at the joints, seams, and where insulation has been compromised. And if air is getting out of your duct system, water is getting in.

Standard exterior ducts often have uninsulated and exposed flanges, air gaps in the insulation, and penetration in the cladding. Water penetration in the jacketing jeopardizes the duct’s structural integrity, contributes to mold and mildew growth in your supply air, and results in a loss of energy efficiency.

Adding more insulation is not the answer to this problem. Adding more R value to a leaking duct system only adds more costs. Three inches of wet insulation is no better than two inches.

Pro-R is a Better Insulated Duct

The most important goal with external ductwork is to eliminate that so-called “acceptable” leakage that systems often experience. Pro-R is that proven solution that maintains R value and IAQ.

Pro-R is based on Kingspan KoolDuct Board, a rigid, high-performance phenolic panel that resists water absorption, sandwiched between two 25-micron aluminum sheets with fiber scrim. This superior insulation is enclosed in the duct by Ducts and Cleats’ double-gasketed construction that promises near-zero air leakage.

The duct features a .040 embossed aluminum jacket far thicker than other jackets used in the field. Integrated four-bolt TDC flanges aren’t just hammered on the end but are connected to the external duct jacket, so there are no seams at those joints. The Pro-R system features no penetrations on the jacketing at all.

This Phenolic duct meets ASTM E84 (25/50 Smoke and Flame), it’s UL 181 listed, and can contribute points for LEED certification.

A Versatile Design

Designed for maximum durability and efficiency, Pro-R is lightweight and easy to install versus standard insulated metal duct. With Pro-R, you don’t need two trades (sheet metal and insulation) for installation.

It is available in a variety of colors, as well as in rectangle, round, indoor, and double-wall formulations.

Specify Pro-R for Best Results

Pro-R reduces leakage, improves thermal efficiency, reduces long-term maintenance costs, increases the system’s lifespan, reduces installation time, and eliminates the need for an insulator.

Engineers should specify Pro-R as basis-of-design (BOD). You can ensure specification by requiring a Class 1 Leak Test, minimal exposed sealant, and minimal penetrations to external jacketing.

We recently hosted Sam Campbell of Furlong Industrial Systems, makers of the High-K Heat Exchanger. In his Coffee Break presentation, Sam explained the advantages of High-K’s shell-and-tube design and in which critical applications it works best.

Our Coffee Break webinars are full of information on the latest innovations in HVAC straight from experts on the technologies. Contact your SVL Sales Engineer for an invite to our future sessions.

What makes High-K’s design different from other heat exchangers?

High-K features a shell-and-tube construction with a true counter-flow design for effective heat transfer. But its main advantage is total serviceability.

The High-K features a tube sheet gasket around the tube sheet, with two steel plates sealing it on either side. If a tube fails or needs cleaning, that single tube can be removed and replaced independently of the entire welded tube bundle. This saves on materials and labor costs over the life of the heat exchanger.

A single High-K heat exchanger contains four shells; the load is 25% per shell, plus some redundancy. During cleaning or a slow season, you can isolate one of the tubes for servicing or cleaning while flow continues through the other tubes. This means all maintenance can be performed with no downtime to the system.

How does High-K compare to a plate-and-frame heat exchanger?

High-K’s one-degree approach makes it comparable with plate-and-frame heat exchangers.

They are larger, however, and space is always at a premium in mechanical rooms. To compensate, High-K has a high degree of design flexibility. It can be hung from the ceiling, mounted on a wall, horizontally or vertically, or even insulated and placed outside.

How does it deal with dirty water better than a plate-and-frame?

The number one complaint from maintenance technicians about plate-and-frame exchangers is that cleaning them is demanding. You must remove each plate, acid wash it, replace each gasket, and reassemble it. With High-K, you simply remove a Victaulic end cap and run a tube cleaner through each tube as you would a chiller.

With plate-and-frame exchangers, the dirty water flows through tiny gaps, getting plugged up over time. With High-K, the 3/4-inch straight copper tubes have no u-bend or catch and feature knurling that breaks up the dirt and keeps the flow moving. Because of the large tube design, it doesn’t require cleaning every season. Some critical applications can go an entire year between cleanings.

Which dirty water systems are suitable for the High-K?

The number one application is pairing with cooling towers. Cooling towers are air scrapers, gathering ambient particulate and drawing it into their system fluid.

If you don’t have a heat exchanger between a cooling tower and a chiller or water source heat pump, whatever particulate the strainer misses will get into the system, quickly derating overall capacity. As little as 1/16-inch of scale on a fluid cooling tower can reduce capacity by 30%.

This is especially important for industrial processes or foundries where the air might be full of particulate. If you need to guard against heavy particulate intrusion, plate-and-frame exchangers will get clogged up faster because of their small channels.

To isolate your cooling tower loop and keep that system truly closed, the High-K is the best buffer between that and your cooling device. Its end caps allow for ease of cleaning the dirty cooling tower side of the heat exchanger, and its isolation valves allow for cleaning without shutting down the system side.