63 minute read
INDUSTRY NEWS
Service Experts celebrates the 100th anniversary of Bryant Heating & Cooling with gift to Make-A-Wish Canada.
BRYANT HEATING & COOLING OF WINDSOR CELEBRATES 100TH ANNIVERSARY On Monday, April 4, Bryant Heating & Cooling Service Experts announced a $75,000 gift to Make-A-Wish Foundation Canada in celebration of Bryant’s 100 years in business in Windsor, Ontario. Bryant became affiliated with Service Experts in 1998. bryantheating.ca
RIGHT TIME GROUP CONTINUES TO GROW AND EVOLVE Right Time Group of Companies continues its growth across Canada with three recent acquisitions, two on Vancouver Island (360 Super Techs and The Comfort Group) and one in Sault Ste. Marie, Ont. (Wardlaw Heating and Cooling).
These acquisitions give the home services group 21 total locations across Ontario, Manitoba, Saskatchewan, Alberta, and B.C. with over 1,000 employees.
Founded in 2014 and headquartered in St. Catharines, Ont., Right Time is majority-owned by Gryphon Investors, a San Francisco-based private equity firm. Gryphon acquired Right Time in December 2020 from Clairvest Group when Right Time had 10 brands and 11 locations.
Last October Gryphon also acquired Southern HVAC, a collection of 15 HVAC brands across Florida, Georgia, Missouri, North Carolina, South Carolina, and Texas with over 650 employees. At that time is was announced that Southern HVAC and Right Time would be rolled under the umbrella of NAEHS (North American Essential Home Services). The two entities continue to operate independently, retaining their existing brands and management teams, while leveraging the combined scale and scope of the two businesses.
At the same time Ian McKeen was named CEO of NAEHS. McKeen, a dual Canadian and U.S. citizen, was previously president/COO of Service Experts (owned by Enercare). right-time.ca B.C. RAISES TAX ON FOSSIL FUEL APPLIANCES, CUTS TAX ON HEAT PUMPS On February 22 the provincial government in B.C. announced changes to its tax laws with direct effects on the heating and cooling industry. Effective April 1, 2022, the provincial sales tax (PST) rate on the purchase or lease price of fossil fuel combustion systems was set to increase from 7% to 12%, while heat pumps are now be exempt from PST.
The PST rate increase applies to fossil fuel combustion systems that heat or cool indoor spaces or water including: boilers, central forced air furnaces, unit heaters, storage water heaters, instantaneous water heaters, air conditioners and fireplaces
HRAI and CIPH both expressed concern over the taxation changes, which ultimatley led to greater clarity and alterations to the original notice with respect to how additional parts and components used in fossil fuel systems are taxed. gov.bc.ca
HRAI TO OFFER IGSHPA RESIDENTIAL TRAINING The Heating Refrigeration and Air Conditioning Institute of Canada (HRAI) and the International Ground Source Heat Pump Association (IGSHPA) have established a training agreement that will make HRAI the exclusive delivery partner in Canada for all of IGSHPA’s residential geothermal courses.
“In light of the growing number of government programs and policies aiming to de-carbonize heating in Canada, the HVAC/R industry is looking to broaden its offerings to include low-carbon technologies such as geo-exchange and, as that segment of the market grows, there will be increasing demand for quality training,” said Sandy MacLeod, HRAI president/CEO. hrai.ca igshpa.org
INTERNATIONAL NETWORK FOR WOMEN IN COOLING LAUNCHED ASHRAE and Women in HVAC&R (North America) are among a group of international organizations involved in the launch of the International Network for Women in Cooling (INWIC) to advance engagement, promote career opportunities and increase participation of women in the cooling sector, including refrigeration, air-conditioning and heat pumps (RACHP).
The initiative is led by the World Refrigeration Day Secretariat and the United Nations Environment Program OzonAction. unep.org
THE “NEW” 2020 NATIONAL MODEL CODES RELEASED The 2020 National Model Codes, the updated set of model construction codes that includes the National Plumbing Code of Canada 2020, National Building Code of Canada 2020, National Fire Code of Canada 2020, and the National Energy Code of Canada for Buildings 2020, are now available.
A volunteer group, the Canadian Commission on Building and Fire Codes (CCBFC), is responsible for the development of the National Model Codes with updates intended to be on a five-year cycle.
Across Canada, provincial and territorial governments have the authority to enact legislation that regulates building design and construction within their jurisdictions. All current provincial and territorial building, fire, plumbing and energy regulations will remain in effect until the new Codes are adopted, with or without modifications, by the provincial or territorial authorities having jurisdiction.
The 2020 Codes include nearly 400 changes from the previous versions. Highlights from the new 2020 codes include: • Performance requirements for HVAC and service water heating equipment are updated to align them with Canada’s
Energy Efficiency Regulations and relevant standards, and to add new equipment types; • A tiered energy performance compliance path which incrementally improves energy efficiency at each successive tier (four energy performance tiers are specified); • Updates to evaporative equipment and drain pans to minimize the growth and transmission of legionella and other bacteria; • The introduction of whole-building airtightness testing as an option for complying with air leakage requirements; • The introduction of encapsulated mass timber construction to allow for the construction of wood buildings up to 12 storeys tall.
The 2020 Codes are available now through the National Research Council of Canada (NRC)’s Publications Archive in a free electronic format for download.
To purchase the publications in print format, an order can be placed online through the NRC’s Virtual Store. <> nrc.canada.ca
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ROAD TO 2030:
DISCUSSING THE INDUSTRY’S APPROACH TO THE FEDERAL EMISSIONS REDUCTION PLANS
Trade contractors are encouraged get out ahead of the curve with respect to energy retrofits and take advantage of the opportunities available.
BY DOUG PICKLYK
Across Canada buildings of all sizes account for 12% of the greenhouse gas (GHG) emissions released into the atmosphere. As a category, the emissions generated by burning fuel to heat homes and office towers are behind only the oil & gas (26%) and transportation (25%) sectors as the most prolific polluters in the country, and that’s why programs are being drafted to encourage change.
This past March the federal government released its 2030 Emissions Reduction Plan, a 271-page document that includes $9.1 billion in new investments designed to ensure Canada will reach an emissions reduction target of 40 to 45% below our 2005 levels by 2030. This target is designed to put the country on a path towards achieving net zero emissions by 2050—a commitment made by countries around the world as part of the Paris Agreement.
Among the spending announced in the new 2030 Plan is $150 million towards the Canada Green Buildings Strategy, a nation-wide game plan to develop new policy incentives and standards to drive new building construction and the retrofits of existing building stock towards zero carbon standards.
According to Kevin Spencer, vice president of energy solutions with Modern Niagara, a national mechanical and electrical commercial contracting company, the demand for decarbonization among new building projects has already started.
“Especially for government projects, there is certainly a focus on GHG targets that must be met by the team that's designing and building the facility, and it has to operate that way as well,” said Spencer during a panel discussion with three other industry experts hosted by HPAC and Electrical Business magazines.
Held on April 25th, the live online panel event, The Road to 2030: Trades Contractors and the Federal 2030 Emissions Reduction Plan, was sponsored by Eaton and Mitsubishi Electric Heating and Cooling. The hour-long event addressed what mechanical and electrical contractors need to know and how they can get out ahead of changes that are coming to the building industry.
When it comes to retrofits of commercial buildings, Spencer is seeing two different approaches among existing building owners. There are companies that have articulated their own climate reduction goals and have started down the emissions reduction path, and then there are the building owners who are in a wait-and-see mode.
“We have an energy solutions group with a number of energy engineers and
HVAC technicians that are looking for better ways to improve not just the energy efficiency of buildings, but now we're also switching over to help our clients decarbonize and electrify,” says Spencer.
And while he’s seeing progressive companies that are in the planning stages, he foresees the actual transition to lower-emissions technology will begin happening between now and 2030.
For residential contractors, the most significant push towards decarbonizing homes is the transition off of natural gas and towards electric heat pump technology for heating and cooling —a solution that's being heavily promoted in jurisdictions across Canada.
Jeremy Sager, a senior HVAC and renewables research engineer with CanmetENERGY (NRCan), addressed some obstacles that contractors need to be aware of to get themselves and homeowners on board with electrification.
“We need to get past the assumption that heat pumps don't work in cold climates,” says Sager. “We've done testing on this technology in our lab … and we've seen that the systems do perform well, even in cold temperatures, some systems performed down to -30 Celsius.”
A range of heat pump technologies exist today, and Sager explains that there are options for those who want to fully electrify their homes or those looking to begin with a dual fuel, or hybrid system, by adding a heat pump to an existing gas furnace, or even those with electric baseboards who could incorporate heat pumps to displace some of their loads with more efficient heat pump solutions.
A challenge he sees is contractors not taking the time to properly size and select systems. “I think calculating proper design, including a heat loss and heat gain calculation, is something that needs to be done to make sure we're getting the systems in the right size to address the load. We don't want Jeremy Sager, CanmetENERGY “I think the more we can get heat pumps into people’s houses the more costs are going to come down and the more heat pumps going to become a commoditized item, like a furnace is for the average homeowner now.”
to oversize, and we don't want to undersize,” says Sager.
While he sees heat gain/loss calculations being more common for new builds, it’s not always built into retrofit projects and that’s a problem.
INDUSTRY ACCEPTANCE
Martin Luymes, vice president of government and stakeholder relations for the Heating Refrigeration and Air Conditioning Institute of Canada (HRAI), is seeing a range of attitudes among members when it comes to transitioning heating and cooling away from fossil fuels. “Among the contractors, it’s a very small percentage of people who are very eager to get into this, but on the other hand, we have people who remain skeptical.”
Industry veterans have experienced government commitments and then withdrawals from low carbon programs and policies in the past. “That creates a bit of an uncertainty around where we’re going, and for contractors to invest in the future of their businesses in terms of product mix and train employees requires clear signals from government,” says Luymes.
“However, I will say, I think more and more our membership is getting the sense that this is an inevitability and they need to start preparing.”
Some concerns about decarbonization and a mass migration to all-electric solutions for heating buildings revolve around the additional load being placed on our existing and aging electrical grid. Canada’s electricity grid is one of the cleanest in the world, with over 80% produced by non-emitting sources, and part of the 2030 Plan includes transitioning the remaining generation to clean sources. And although there are other “clean” alternatives for heating, such as hydrogen and biomass as alternative fuel sources, electricity is the leading solution.
“When it comes to clean energy, or reducing carbon emissions, electricity has and will play an important role in achieving those goals,” says Gurvinder Chopra, vice-president standards and regulations with the Electro-Federation Canada. “Our research and development teams are spearheading their product designs in that direction.”
Electrical grids and electrical products are all going through a transformation as technology and innovation are disrupting the traditional models, notes Chopra, who points to three key trends leading the disruption: the electrification of the transportation sector; decentralization or distributed energy resources (DERs), where localized energy generation and storage meet demand flexibility and energy efficiency; and the digitalization of the grid including smart metering, smart sensors and automation beyond the meter.
With respect to concerns about grid capacity, Chopra explains that it is clear from many studies that unless there is a very sudden upsurge, the current power system is capable of absorbing additional loads. He does acknowledge there is a need for invest-
The virtual Road to 2030 round-table discussion included: (clockwise from top left) Doug Picklyk, HPAC; Gurvinder Chopra, Electro-Federation Canada; Martin Luymes, HRAI; Jeremy Sager, Canmet ENERGY; and Kevin Spencer, Modern Niagara.
ments and operational adjustments including replacing aging, inefficient electrical infrastructure, and using energy efficient products.
RETROFIT OPPORTUNITY
The transition of buildings away from fossil fuels to electrification for heating and cooling does provide a “massive opportunity” for contractors, suggests Spencer. And although he admits the government messaging with respect to incentives doesn't seem to be uniform across the across the country right now, he is confident that the traditional course of action for lifecycle replacement—swapping out fuel-burning equipment for the same thing—is going to be disrupted.
Sager also sees a huge opportunity on the residential side with air conditioner replacements. “Let's look for ways to swap out [the AC unit] for an equivalent capacity heat pump, if that's what the homeowner is looking for,” he says.
“Our research has shown that if you do go this route, you can still generate 25 to 30% GHG reductions if you swap an air conditioner with a like-for-like heat pump.
“I think the more we can get heat pumps into people’s houses the more costs are going to come down and the more heat pumps going to become a commoditized item, like a furnace is for the average homeowner now.”
Contractors can also offer solutions to homeowners that can optimize their heating systems to be lower cost or to release fewer GHG emissions.
In jurisdictions like Ontario, where there is time-of-use electricity pricing, smart switching controls can be incorporated with the use of hybrid (or dualfuel) heating systems—using an electric heat pump in tandem with a gas-fueled furnace—and the controls will ensure the homeowner is operating the leastcost heating system at all times.
“I would encourage contractors and distributors to ask for these kinds of capabilities from their equipment suppliers,” says Sager, who also suggestsmaking homeowners more aware of ground source systems as well as the air source heat pump options.
TAKING CHARGE
As different levels of government continue to develop new plans and directives to drive Canadians towards new emission-free ways to heat and cool homes, both Luymes and Chopra agree that industry needs to be at the table helping to set the agenda.
“One of the things we need to do as a sector across the board, is to send a signal to utilities and governments at the provincial, federal and even municipal level that we have solutions, we have ideas about leading the way in the drive to low carbon technologies,” says Luymes.
For example, HRAI conducted research that shows that a greater adoption of ground source heat pumps, rather than relying 100% on air source heat pumps, could provide great benefits to managing the grid because the ground source systems don't peak any-
where close to the same level on the coldest days of the year.
Luymes points to this research being helpful to the electrification policy discussion. “It doesn't really say one technology is better than the other—it’s more about showing there are considerations that need to be thought through when we’re talking about electrification.”
According to Chopra, almost every member of Electro-Federation is aligning with climate change. “I mean, they have to be, there's no other option. They’re all helping the customers and suppliers to implement sustainable practices across the value chain and throughout the lifecycle of their products and solutions.” He also highlighted one member company that has supported two apartment buildings in Switzerland with carbon neutral energy production and with no-cost electricity or heating for the tenants with photovoltaic modules installed on the front and on the roofs, and with two wind turbines. “The production covers energy demand for heating and cooling, and the production of hot water for all residents. The system also manages switching from one source to another at optimal times, switching power on and off to manage efficiencies and costs. So, all this is happening as we speak, and as Martin mentioned, we need to have proper policies in place which would help these going forward.”
Kevin Spencer, Modern Niagara “The selling is shortsighted, … now is the time to be presenting other options with longer-term benefits for clients.”
Gurvinder Chopra, Electro-Federation
SELLING THE LIFE CYCLE
The panelists all agreed that where the greatest gap exists in the industry today is in the number of properly-trained technicians and the lack of long-term thinking when it comes to selling HVAC systems.
“When you’re dealing with a building owner, and whether it’s HVAC equipment or whatever it may be, the focus is typically always on installed price,” says Spencer. “And yet there’s so much more that goes into it—there’s the energy consumption and the air tightness of the building—and it doesn’t really matter if it’s a residential building or a commercial building, but we really are lacking the skilled expertise to look at a building, and the systems in that building, and come up with solutions for that client where we can say: ‘Here’s what the financial cost over the lifecycle of that equipment will look like for you. Today, if you put in a heat pump, whether it’s ground source or air source, it will absolutely under its lifecycle be more cost effective than fossil fuel based natural gas.’”
He sees the selling process today to be too short-sighted. People are replacing gas appliances for similar products because it’s familiar.
“But carbon pricing is escalating, so when you look out even eight years from now pricing will change. So now is the time to be presenting other options with longer-term benefits for clients.”
Selling against the rising carbon price is seen as a short-coming for the industry. “If you’re not thinking about that, and presenting the alternatives to your customers, you’re really doing a disservice,” suggests Luymes.
HRAI has been working on a plan of training programs for a low carbon future. It includes re-training programs for existing HVAC technicians as well as developing a new pathway to attract new technicians for the residential heat pump trade.
But by far the biggest need, says Luymes, is to get people to understand how to sell the solutions. “There’s all kinds of new technologies and people have to technically understand how to install and service them, but also, how do you sell them, particularly when the price point is a bit higher than what people are used to?”
Sager and Luymes also see opportunity in the market for existing contractors to join forces to provide a broader suite of services to address energy retrofit solutions for businesses and homeowners. HVAC contractors can take the lead on the mechanical room, while electricians manage solar solutions and smart controls, while another contractor takes care of the windows, insulation, weather stripping etc. Very few companies are in a position to offer the whole suite of services and that could create a new business model.
“And I would suggest that contractors who think about leading with their own expertise and broaden into some of those other services will be doing themselves a favour,” says Luymes. “They’ll also be doing their customers a favour and will be positioning themselves for long term success.” <>
To view a recording of the entire Road to 2030 session visit hpacmag.com.
HUMIDITY PIPELINE
Approaches for dealing with the challenges of hot and heavy weather systems in central and eastern Canada. BY IAN McTEER
As a kid, I never noticed how bothersome hot and humid weather would become in southern Ontario during our glorious summers. I was too focused on enjoying those days.
Years later, I learned about the number of days and hours a specific area would experience different temperatures throughout the year. For example, in a document created by Lennox and published in the 1986 version of the Air Conditioning Contractors of America (ACCA) Manual J, the Greater Toronto Area (GTA) can expect to experience an average of 709 hours (30 days, roughly) at or above 75F (24C). By comparison, Miami, Florida has an average of 5,273 hours at or above 75F. Nothing about humidity though.
Well, we’ve all heard of oil, gas, water, sewage and steam pipelines, but what about a humidity pipeline? Well, there is a particular weather phenomenon that occurs regularly during our summers in much of eastern Canada. Weather observers talk about a “pipeline” that opens between the Gulf of Mexico and southern Ontario through to southern Quebec and points east.
The pipeline encourages a flow of incredibly hot and humid air, typically relegated to the Southern U.S., up the Mississippi and Ohio River valleys to the lee of the Appalachian Mountains and into our region.
Often lasting for several days and periodically opening and closing the flow of moisture almost anytime from June to late August, the moist air pushes the socalled humidex readings beyond 105F (40C) in some areas causing health problems and generalized misery for many people who’ve long since turned to cooling systems for relief. When moisture condenses on the outside of the windows, that’s a pipeline day.
I once spent some time in New Orleans during July where I learned from the locals that only tourists visited the beautiful parks during the summer. I saw a mobile home with a 5-ton packaged unit installed into a large window opening; it’s so hot that shipyard welders started their day shift at 3:00 a.m. going home at noon to avoid the worst of daytime heat; some people slept outside when the cooling system goes down. This kind of extreme weather, visited upon unsuspecting Canadians, is truly behind our robust cooling industry in eastern Canada.
HUMIDITY: GOOD OR BAD
Someone once said, “moderation in everything.” Scientists and HVAC engineers have determined, especially considering Covid-19, that maintaining a consistent level of moisture in the air inside buildings helps to prevent some health problems. Keeping the level of humidity within the home somewhere between 35% to 50% should be the gold standard for moisture control.
Too much moisture damages buildings, creates ideal conditions for bacteria and viruses, and allows dust mites colonies to multiply, while too little moisture is equally hospitable to potential pathogenic organisms.
Out of control moisture levels within the home (leaving thermal comfort aside for a moment) creates ideal conditions for the growth of dangerous mold, often in places the average homeowner doesn’t realize even exist.
Sometimes, a minor renovation will expose a world of fungi happily doing their thing, as can be seen in Figure 2 below.
In our northern climate, maintaining an appropriate level of humidity during the winter months is one thing, but rarely do summertime moisture levels in the home warrant much discussion beyond the old standard complaint: “It’s not the heat, it’s the humidity.”
The curious thing is that eastern Canada, affected by the “pipeline,” does have a humid climate. Engineers classify humid climates as having an average dew point of 56F (13.3C) or higher. Ottawa, often described as the coldest capital city in the world, also possesses an average dew point in July of 59F (15C) (source: timeanddate.com/weather/canada/ottawa/climate), and when the “pipeline” gets going the dew point can exceed 70F (21C) for days at a time.
Temperatures can soar in other parts of Canada, the prairie cities often experience high temperatures, but rarely is moisture a problem because weather patterns allowing for the incursion of hot and humid Gulf of Mexico air do not exist in other parts of Canada.
We have learned so much about how buildings function throughout the years, especially how to reduce energy consumption while maintaining a healthy indoor environment. Yet, there are more than 4 million homes in Ontario alone that were built without deference to energy performance and ventilation.
I think it’s safe to say that many of those houses have been retrofitted with new windows, doors, furnaces and cooling equipment over the years, but too often the cookie cutter recipe used for HVAC systems continued the use of the original cookie cutter. However haphazardly the retrofits were made over the years, studies have shown that HVAC systems are too often oversized!
MOISTURE HAS A SOURCE
Visible sources of moisture are easily recognized as liquid water leaking into the building from roofs, windows, doors, and faulty drainage from sinks, tubs, showers and so on. I’m talking about the invisible sources that cooling systems typically are not designed to deal with.
Sources of moisture, such as vapour diffusion, are difficult to find and not always easily explained to homeowners. Many sources in the house include: cooking, bathing, hot tubbing, indoor gardening, toilet seats left up, plus the added potential sources from the mechanical system such as constant fan operation in cooling season, oversized cooling systems and leaking ductwork complicate the matter too.
Basements rarely ever require mechanical cooling, unless some heat producing process is going on down there, because the ground temperature is such that heat will flow from the basement into the cooler ground all year. But what about water vapour? Water vapour can diffuse thorough solid materials or simply barge in through open doors and windows whenever
Figure 1. Condensation on windows from high humidity.
Figure 2: Renovation project reveals hidden mold.
there is a difference between the indoor and outdoor dew point.
Suppose a cooling system can maintain a sensible temperature of 75F (24C) at 50% RH; plot those conditions on a psychometric chart and find the dew point will be a reasonably comfortable 55F (13C). On a hot “pipeline” day (say 70F (21C) dewpoint), an older, leaky house with its cooling system working overtime is a candidate for an invasion of moisture by convection through gaps, holes, open doors, etc., and by vapour diffusion.
Even a small difference in dew point across building materials such as drywall, wood, and even insulation, means there will be a transfer of moisture across those materials, from the higher dew point temperature to the lower dew point temperature.
MECHANICAL ISSUES
Whether the house is new or old, an accurate load calculation will ensure the proper equipment will be specified for any job. The goal of any HVAC system must be to transfer heat as efficiency as possible, yet numerous studies consistently show mechanical system flaws lead to poor performance, lack of humidity control and higher than anticipated electricity consumption. Combined with lack of maintenance, too many systems are wasting precious energy resources.
The most common mechanical problems in the millions of
older “pipeline area” houses, especially if they’ve been haphazardly renovated, almost need no introduction: • Oversized cooling equipment (and furnaces, too) that short cycle reducing only the sensible load. • Improper equipment selection leading to high evaporator dew point temperature. • Improper air flow outside of the manufacturer’s recommendation of 350 to 450 cfm per ton; airflow is often too low because of undersized or improperly installed duct systems. Sensible capacity increases by about 7% at higher airflow and decreases at lower airflow. Because latent capacity is reduced somewhat at 450 cfm per ton, standard procedure in Ontario has been to use airflow settings ranging from 350 to 400 cfm per ton. • Remember, many houses built in Ontario had duct systems designed for furnaces with a temperature rise of 100F or greater, no such thing as future proofing back then. The residential cooling market was in its infancy; no one thought furnaces of the future would require 45% more airflow.
Without renovation, it’s impossible to guarantee energy savings from modern forced warm air mechanical equipment. • Studies also show that unsealed duct systems lose about 25% of cooling system performance because the conditioned air is not getting to the places where it’s needed. In basements where ductwork is exposed, all trunk duct joints and perimeter pipe take-off fittings must be sealed (see Figure 3, next page).
WHAT CAN BE DONE?
Fortunately, for many of us, we don’t have a summer climate anything like the southern United States. Miami, Florida has a July dewpoint of 73.4F (23C), conditions we in eastern Canada see only when the pipeline is flowing in full force.
Even though our residential cooling equipment might run thousands of fewer hours than our mechanical colleagues down south, it is nevertheless vital that our cooling systems match the sensible load as closely as possible.
And we do know that controlling humidity has everything to do with human comfort along with reducing embryonic outbreaks of pathogenic organisms and reducing potential property damage caused by unwelcome moisture incursion.
So many of the four million or more homes (in Ontario alone) have second-rate air handling systems, it might be better to abandon the existing forced warm air duct system altogether. Without proper airflow, equipment run time is compromised so that providing effective cooling and humidity control is impossible.
Continued on p20
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In such cases, I think a cold climate heat pump using floor mounted terminal units (or a combination of wall and floor mounted units) would provide superior cooling and humidity control along with efficient heating.
Older houses are inherently inefficient because there is too great a temperature difference between the inhabitant’s skin temperature and the temperature of surrounding infrastructure such as walls, doors and windows. For the average consumer looking for a low-cost cooling unit installation, it’s not likely they’ll be interested in spending more money on building envelope improvements.
HVAC sales professionals must consider offering strategies to maintain a suitable relative humidity in the house during the cooling season, however, depending on the condition of the house, when a human needs analysis combined with all the necessary industry parameters are included in the kitchen table quote, the cost perspective may be daunting to some consumers. Workarounds may be possible, but the “we’ve always done it this way” approach isn’t helpful.
Figure 3. Unsealed duct systems lose about 25% of cooling system performance.
Here are some strategies to consider: • Do a load calculation to be sure the equipment is not oversized yet can run long enough to condition the living spaces but not the basement (walk out basements excepted).
Today’s cooling units feature much larger evaporator coils often taking more time to absorb heat through the mass of the coil, thus 15-minute cooling cycles will do little in the way of controlling humidity. • Inverter drive compressors com-
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Figure 4. Example of a ventilating dehumidifier.
bined with variable speed indoor blowers providing capacity control is a good way to go for older houses, provided the existing duct system is appropriately sized and properly installed. • Install a smart thermostat capable of controlling the indoor blower so that dehumidification cycles are enhanced, and that the continuous blower operation will cease if the RH climbs beyond 55%. • Recommend an ERV for all-year ventilation, but do a blower door test as well to be sure only the necessary amount of outdoor air is provided. Older houses are leaky: reduce infiltration as much as possible. Some situations might benefit from a ventilating dehumidifier (see Figure 4, above). • Homeowners should be aware of new generation ventless
clothes dryers and heat pump water heaters. Eliminate air exhausting appliances! • A zoning system utilizing outdoor unit compressor capacity control (inverter drive, two-stage or two-step) combined with variable speed indoors and a smart controller that provides system relief (no bypass) could be an option when all the ductwork is exposed in an unfinished basement.
With the advent of smart thermostats capable of monitoring and reacting to humidity levels, I think it’s best to provide a system that will efficiently keep an older “pipeline” house at 74F and 50% RH.
We know that longer run times (not too cold), less moisture coming in from outside, less indoor moisture generation, and simple things like keeping the doors closed and windows shaded on pipeline days makes for effective cooling, but in the end our customers will do what they will.
When the annual humidity pipeline opens yet again, let’s make sure they’re ready. <>
Ian McTeer is an HVAC consultant with over 35 years of experience. He was most recently a field rep for Trane Canada DSO. He is a refrigeration mechanic and Class 1 Gas technician. Ian can be reached at imcteer@outlook.com.
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MINI SPLITS AND SYSTEM DESIGN
BY GERRY WAGNER
Homeowners seem to have a perception of mini splits which over simplify their application and installation. Truth be told, mini splits often find themselves bunched together with window units and free-standing portable AC units in the collective mindset of the buying public.
This perception is unfortunate, inaccurate and frankly, not healthy for the HVAC industry.
I have two curriculums that I conduct for the inverter mini split product line I represent in Canada, one being Sizing, Design & Installation and the other, Troubleshooting.
Sizing, Design & Installation, yeah, you heard me “DESIGN.”
After a sale, installation is not simply slapping an evaporator on a wall and attaching it to an outdoor unit in the closest possible proximity. Installers must first be system designers to ensure a system meets the needs and expectations of the homeowner and at the same time performs to its fullest potential.
A professional installation starts with a proper heat gain/heat loss calculation, in Canada the industry standard being the CSA F280–12 Standard for residential applications or the Air Conditioning Contractors of America (ACCA) Manual J.
A professional installation then continues beyond the sizing calculation with a proper system design.
Where is the best placement for the evaporator? The outdoor unit? How to best run the lineset, condensate drain tubing and power/communication cable between the indoor and outdoor unit? These concerns are just that, concerns that must be addressed before holes are drilled through walls.
I always promote the evaporator be placed on an outside wall for no other reason than ease of installation. (This regular “Duct Free Zone” column of mine is directed at the HVAC/R trade, not to homeowners, so I’m speaking to my trade brothers and sisters here.) It is in our best interest to install the wallmounted mini split indoor unit on an outside wall for ease of lineset, condensate drain and electrical cable run. Nine times out of 10 with single-zone systems your outdoor unit will be just on the other side of the outside wall where you are installing the evaporator, and that makes our job as installers a whole lot easier, and there is nothing wrong with trying to make your job easier.
Also, nine times out of 10 I’m going to centre the evaporator on the outside wall onto which it is being installed for no other reason than aesthetics—it looks better when it is symmetrical.
The 10th time is when I’m trying to effect more than one room with a single evaporator, and this is a very common and very acceptable design alternative. There are any number of reasons why I might use one evaporator to service more than one room: open floor plan, difficulty in installing a second evaporator and the most common reason, simple economics.
In my Sizing, Design & Installation curriculum, I speak to the need to be able to accommodate all of our customers, not just the ones with an excess of disposable income, but also those who are on a tight budget. Utilizing one indoor unit to service more than one room, where applicable, can be a significant cost savings, and that makes sense for everyone.
I don’t want to imply that mounting the evaporator on an interior wall is a
no, no, or in some way a poor design. Clearly there are applications where an interior wall is the best location, but when we do install on an inside wall additional accommodations must be made for condensate removal (pump), not to mention lineset and electrical cable routing.
I always stress that as designers and installers we must make sure the homeowner is onboard with our design and understands it. The homeowner can’t do something that impedes that flow of air after you leave, compromising your system design (i.e. they can’t put a bookcase in front of the evaporator if you are trying to have the throw of air from that single indoor unit effect more than one room).
I always make a point to mention in my training that I’m not there to disparage conventional ducted “unitary” type systems, ducted systems should not, and will not disappear. Mini splits are simply an alternative to the conventional ducted system. Sometimes a better alternative, but not always!
Those of us who have designed and installed ducted, unitary type systems, from scratch, whether it be new construction or renovation, wouldn’t think of doing so without a proper system design and mini splits should be no different!
Let’s be honest here, the primary reason mini splits have taken this long to take hold in Canada, when the rest of the planet went ductless decades ago, is the mini split evaporator. The advent of alternatives to the “high wall mount” evaporator, like ceiling cassettes and ducted evaporators, create even greater emphasis for the need for proper mini split system design. These evaporators, though more discrete and aesthetically more “familiar” in appearance, do have their own unique installation requirements.
Harry Eklof, founder of Harry Eklof & Associates, one of the premier manufacturer’s representative agencies in our industry and one of my most valued mentors, both in life and in business, had an expression: “perception is reality.” Harry recognized how perception, no matter how inaccurate it may be, is reality to those who don’t know better.
We as HVAC/R professionals must understand that no matter what the perception the homeowner has of inverter mini splits, we know better and must give mini splits the same respect and consideration that ducted, unitary systems have enjoyed for generations. <>
Gerry Wagner is the vice president of business development for Bathica. He has 41 years in the HVAC/R industry working in manufacturing, contracting and training. He can be reached at GerryWagner@ Bathica.com. www.TOSOTamerica.com
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Indoor Air Quality is a vast topic with an almost exhaustive list of solutions for HVAC professionals to provide comfortable climates for homeowners and commercial building operators. Following is a collection of products to get you familiar with some options available on the market.
RenewAire has introduced the EV Series Premium–Model S, a static plate enthalpy corebased ERV for smaller IAQ-oriented applications. Like the larger EV Series Premium models, the Model S offers top-level CFM/watt, exhaust air transfer ratio and static pressure capabilities with customizable features. The unit is Home Ventilation Institute (HVI)-certified (CSA 439-09) and designed for new 3-bdrm/2bath single-family homes under 2,500 sq. ft., condos, dorms and light commercial buildings. More features include variable fan speeds supplying 30 to 130-CFM by an EC motor, digital controller for quick balance/airflow adjustments, and MERV 13 filters. renewaire.com Fresh-Aire UV has added the APCO-X MAG, an addition to the APCO product line of combination ultraviolet (UV) technology and activated EverCarbon media catalyst air treatment for HVAC systems. The new unit’s magnetic mounting bracket’s compact footprint is designed for installation flexibility near the evaporator coil, plenum or duct. The mount attaches to metal cabinets and its anti-vibration coating prevents wandering out of position. It also features a three-year UVC (254-nm) quartz lamp and UL-2998 validation as free of potentially harmful ozone. The unit also features the APCO-X’s V-Twin Cell Matrix incorporating lifetime ceramic cells infused with EverCarbon media. freshaireuv.com Panasonic’s WhisperAir Repair air purifier features nanoe X air purification technology that uses moisture in the air to neutralize pollutants. These air purifiers maintain healthy indoor air quality by suppressing airborne and adhered pollen and other allergens, inhibiting odours, and breaking down hazardous substances. The units are maintenance free with no filters to change and no duct work required. Suitable for remodels, retrofits or new construction, WhisperAir Repair can be mounted in most ceilings, and the paintable, low-profile grille blends into any room. panasonic.com
European manufacturer VENTS offers an innovative single room WiFi-enabled energy recovery ventilator (ERV). The TwinFresh Expert provides continuous ventilation all year with a 93% efficiency. The units offer three speed levels, various ventilating modes, efficient filtration, wall-through plug and play installation, quiet operation and modern design. The units are suited for a comfortable indoor climate and
required air exchanges in renovated premises, recently inhabited houses or reconstructed apartments. vents-us.com The Respicaire BioClean is a high output, UVC germicidal purification system designed for commercial air and coil disinfection for large rooftop units (RTUs) and air handling units (AHUs) up to 100 tons. The units include high intensity UVGI lamps with telescoping bars for easy retrofit and magnet mount brackets for diagonal, horizontal and vertical installation. BioClean has been engineered for surface and airstream decontamination. Proven to be test-
ed on the pandemic corona virus and shown to inactivate 99% in seconds, the BioClean helps eliminate coil biofilm while inactivating airborne microbials and pathogens. The product is suited for indoor air quality solutions. respicaire.com The Air Excellent air management system from Centrotherm provides draft-free, noiseless fresh air supply to living spaces and efficient stale air exhaust from kitchens and bathrooms while contributing to energy efficient homes and creating a better overall environmental footprint. Air Excellent is a fully configurable system that simply clicks together to form an air-tight seal and with flexible vents it allows for complete customization while allowing installers to independently control the air quality in each room. The system was designed to increase oxygen levels while reducing carbon monoxide, VOCs, viral load, bacteria, and mold growth. airexcellent.ca
The Kaiterra Sensedge commercial indoor air quality monitor allows users to monitor air quality, volatile organic components like CO2 and other harmful matter that pose risks to building occupants. It uses a real-time dashboard for reporting, monitoring, and analysis, allowing users to act before they have to react, preventing repairs and unnecessary building closures. The Sensedge uses removeable sensor modules for easy replacement. The system supports connections to the cloud for data reporting and BACnet for local building automation system integration. kaiterra.com
The Condair HumiLife whole-home steam humidifier is direct furnace mounting so it saves space in any residential mechanical room. The system uses steam to create hygienic, wholehome humidity. Steam is vented through forced air ventilation units and automatically regulated to prevent dry air while also adhering to harmful aerosols like pathogens and allergens. There is no standing water, so mold and scaling will not accumulate in the cylinder. The unit is capable of using three sensors to automate humidity output, so homeowners minimize water and electricity usage while enjoying comfort in the whole home. It can also be remotely controlled through a built-in app on a phone or tablet. Patented auto-adaptive water management maximizes the humidifier’s cylinder life. condair.com/residential Venmar Ventilation’s Canadian-made Venmar AVS N series and vänEE AI series heat recovery ventilators (HRV) and energy recovery ventilators (ERV) feature new VIRTUO air technology offering improved performance and quick installation. Their smart, built-in, auto balancing allows quick set up, and the continuous self-adjustment optimizes operation and simple touchscreen controls allow simple settings. They come standard with MERV 8 filters and MERV 13
are an option. www.venmar.ca
The Central Air Controller from HAVEN combines with the company’s Central Air Monitor to makes home HVAC systems healthier. The Air Monitor is mounted directly within the duct and combines miniaturized particulate sensing lasers and chemical sensors to detect levels of airborne contaminants. The Controller automatically optimizes HVAC system filtration, ventilation, or humidity levels on-demand. Data is available via an IAQ app to homeowners and HVAC professionals. haveniaq.com. The ODD-ERV-120 from Ortech is an energy recovery ventilator (ERV) with washable MERV 6 air filters in the return and outside supply air streams. The ventilator with enthalpic core provides both heat and humidity recovery. The units feature EC motors with total speed controllable range and offer performance up to 77% SRE. The system also has automatic recovery core defrost mode and also offers an optional touchscreen controller. ortechindustries.ca
Yorkland Controls offers a selection of IoT-ready IAQ sensors that make it possible to continuously monitor indoor air quality for building occupants. Smart IAQ sensors transmit data to building automation systems and centralized IAQ analytic platforms to control and validate ventilation control strategies. The sensors monitor and control based on air pollutants such as PM2.5,PM10, VOC, CO2, and ozone. yorkland.net
Sanuvox’s Bio-Wall air disinfection system is a customized solution to help prevent propagation of bioaerosols in even the largest air handler units. Installed in ventilation ducts, this UV purifier has been shown to effectively reduce airborne concentration of biological pathogens, like mold, bacteria, and viruses (such as SARS-CoV-2).
SIMPLE & REPEATABLE
Delivering comfort and convenience by combining single zone cooling and multizone heating using heat pump system designs.
BY JOHN SIEGENTHALER
The versatility of modern hydronics technology allows designers to create systems that are “customized” to the needs, and constraints of almost any building. While best known for space heating, most modern residential systems also include provisions for heating domestic water.
Still, for decades, one of the “shortcomings” of smaller hydronic systems has been the inability to cool buildings, undoubtedly swaying many prospective clients to ducted forced air because it provides both heating and cooling.
This long-standing shortcoming is changing as the future of energy supply for heating continues to progress away from fossil fuels and toward electricity. Heat pumps, in both air-to-water and geothermal water-to-water configurations, are increasingly being used instead of fossil fuel boilers. This transformation brings the ability to provide chilled water cooling, and thus a more complete solution to comfort. That’s a really “big deal” in my opinion.
A GREAT COMBINATION
An approach I like to promote is multiple heating zones in combination with single zone cooling. The heating distribution system could use one type or a combination of heat emitters.
An example would be radiant floor, wall, or ceiling heating in some areas combined with panel radiators in other areas. Ideally, all heat emitters would be sized for the same supply water temperature. This keeps the system simple by eliminating the need for mixing.
Figure 1 shows a combination of heat emitters, all served by homerun circuits of ½-in. PEX, PE-RT or PEX-AL-PEX tubing from a common manifold station.
Flow to the manifold station is provided by a variable speed pressure-regulated circulator set for constant differential pressure. Each emitter is equipped with a non-electric thermostatic radiator valve. That valve is built into the panel radiators. The only thing needed to make each panel radiator into an independently controlled zone is to screw a thermostatic operator onto that integrated valve.
The other two circuits show a combination of floor heating and a towel warming radiator. Flow through these circuits is controlled by an external thermostatic valve equipped with a remote adjustment dial typically mounted to a wall.
This combination of thermostatic valves provides five independently controlled heating zones. As the valves open, close, or modulate flow, the variable-speed pressure-regulated circulator senses the “attempt” to change differential pressure and immediately adjusts motor speed to cancel out that attempt. This allows the flow in each homerun circuit to remain stable regardless of what zones are active.
Figure 1. A combination of heat emitters all served by homerun circuits from a common manifold station. HOT & COLD
In Figure 2 (page 30), a low ambient (split system) air-to-water heat pump is the source of heating (and cooling).
The heat pump is equipped with a variable speed inverter drive compressor, allowing it to modulate both heat output and cooling capacity down to about 40% of peak rating. The compressor speed changes based on maintaining user-specified leaving water temperatures for heating mode and cooling mode operation. In most systems this allows the heat pump to
supply an air handler sized to the building’s cooling load without use of a buffer tank—provided the air handler is not smaller than the minimum cooling capacity of the heat pump, and there is only one zone of cooling.
As a “split system” there is no water in the outdoor unit, and thus no need to protect it from freezing. This eliminates the need for antifreeze, which is required when a monobloc-type air-towater heat pump is used.
The diverter valve directs flow leaving the heat pump to the heating or cooling portion of the system. It should be configured with its normally-closed port, which is usually designated as “A” supplying the heating portion of the system, leaving the normally open port, which is usually designated as “B,” to supply the cooling mode.
The “A” port should only open when the heat pump is operating. This allows the diverter valve to prevent reverse thermosiphoning through what could otherwise be an unblocked piping path between the upper and lower portions of the tank. It also eliminates the need for a check valve to otherwise prevent reverse thermosiphoning.
The air handler supplies a ducted distribution system. Since this portion of the system is for cooling, the ideal arrangement would put the outlet registers in the ceiling or high on the walls. This allows the cooled air to mix with room air without creating drafts.
In cold climates it’s best to install the air handler in conditioned space. This all but eliminates the possibility of freezing water in the air handler’s coil during winter. It also reduces the potential for energy-wasting convective air flow through the air handler and ducting due to temperature stratification in the building.
If the air handler has to be mounted in unconditioned space some means of freeze protection is required. The possibilities include draining the coil during winter, using anti-freeze in the system, building an insulated enclosure around the air handler, or installing heat tracing cable and hoping that no long duration power outages occur. I’m not a fan of any of these if they can be avoided.
Even small air handlers can generate several gallons of condensate when operating in cooling mode on a humid day. Be sure to pipe up a condensate drain.
Depending on applicable codes, this drain might be connected to the buildings DWV system, or it may have to be routed to a separate interior or exterior drainage point.
When the air handler is installed above finished ceiling I recommend installing it over a secondary drain pan that would capture leaks from the air handler’s internal drip pan and route them to a suitable drain.
Figure 2. An example of a low ambient (split system) air-to-water heat pump used for heating (and cooling) energy.
THERMAL FLYWHEEL
The final subsystem is a reverse indirect tank that provides buffering for the space heating zones, which typically have heat transfer requirements much smaller than the minimum heating capacity of the heat pump. The concept is shown in Figure 3 (page 32).
The tank piping is configured around one currently available reverse indirect. It’s a “two-pipe” configuration, which allows for “direct-to-load” heat transfer at times when the heat pump is running at the same time as space heating load.
THE BRAINS
During heating mode operation the temperature of the buffer tank is monitored by a setpoint controller. When the sensor at the midpoint of the tank drops to some minimum value the heat pump is turned on. This happens regardless of any demand for space heating.
The goal is to keep the water in the tank’s shell warm enough to provide domestic water heating (or preheating) whenever there’s a draw at a fixture.
Once turned on, the heat pump continues to operate until the tank sensor reaches some upper limit. That limit should be several degrees lower than the safety high limit setting programmed into the heat pump’s internal controller.
This is where a tradeoff needs to be made. The lower the temperature at which the buffer tank is maintained, the higher the heat pump’s coefficient of performance. However, for tank temperatures below about 115F, the domestic hot water (DHW) will only be “preheated” rather than fully heated. Preheated domestic water requires a temperature boost prior to use at fixtures, and that boost could come from a single electric on-demand tankless heater. It could also come from multiple smaller-capacity electric tankless heaters located close to each fixture.
It’s also possible to base the buffer tank temperature on outdoor reset (rather than setpoint) . The warmer it is outside the lower the buffer tank temp.
This keeps the water in the tank just hot enough to provide the building’s
current heating load. Still the lower the tank temperature, the greater the required boost in DHW leaving the tank.
The “optimal” temperature control for the tank must factor in the energy used for space heating and DHW, the COP of the heat pump operating over a range of both water and outdoor temperatures, and the cost of electricity used for direct resistance heating.
Based on simulations I’ve done there appears to be a slight advantage to controlling the tank based on outdoor reset, versus maintaining the temperature high enough to provide DHW.
During cooling mode the heat pump monitors its leaving water temperature, and adjusts compressor speed to maintain a suitable setpoint, typically in the range of 45F to 50F. DHW FIRST
To ensure DHW availability the system’s controls give priority to maintaining the temperature in the tank. When required the heat pump switches from chilled water to heating mode. The time to boost the tank during warm weather should be minimal because the system is operating at high heating capacity.
When the tank reaches is upper temperature setting the heat pump switches back to cooling. At that time the heat pump and nearby piping contain hot water. It typically takes about three minutes for the heat pump to restart in cooling mode. It may take another two to three minutes to chill down the water in the heat pump and surrounding pipe. During this time the system controls should keep the blower in the air handler off to prevent a short burst of warm air from the ducting system.
Figure 3. The complete system including the indirect water heater.
IT’S IN YOUR FUTURE
The ability of heat pumps to provide cooling through a central air handler, combined with heating by individually controlled panel radiators, is a simple and repeatable concept that’s ideal for modern homes, especially those aspiring to net zero status. <>
John Siegenthaler, P.E., has more than 40 years of experience designing modern hydronic heating systems. He is the author of Modern Hydronic Heating (4th edition) and Heating With Renewable Energy (visit hydronicpros.com).
AIR QUALITY AND ENERGY EFFICIENCY: PART II
In this example we take a look at the economics of swapping out a VAV system for a DOAS and chilled beam solution for a low-rise office building. BY MIKE MILLER
In part one of this article (March 2022) I spent some time reviewing the need for enhancing the amount of fresh air ventilation in buildings, one of the key recommendations from the international health and science advisory bodies during the pandemic. I then went on to share one of many options available to achieve greater fresh air exchange in buildings through the use of a hydronic system solution using a dedicated outdoor air system (DOAS) in combination with active chilled beams. This solution, with the proper controls in place, can achieve well-conditioned fresh air in occupied areas, and it can be incorporated into buildings as a retrofit or designed into new installations, all while effectively managing energy consumption.
For this article we’re going to analyze the potential benefits and energy savings in a typical commercial building.
LOW-RISE COMMERCIAL
To show how a DOAS/chilled beam solution could operate, we’ll look at an existing low-rise commercial building designed and operating using a variable air volume (VAV) HVAC system.
We’ll consider an office building with five floors, a total area of around 200,000 sq. ft. Our sample building uses the current ASHRAE ventilation guidelines of 17 cubic feet of air per minute (CFM) per person. Using a conventional HVAC system based on 400 sq.ft./ton, we'll have a total of 500 tons.
To calculate a total annual operating cost we’ll use $0.15/kw-hr and $0.95/ Therm, so we arrive at $360,000 (numbers for demonstration only).
Figure 1. A typical five-story low-rise building.
VAV AIR HANDLER
A conventional VAV air handler handles total load (latent and sensible) for a building. In our example (see Figure 2) the air handler design has a recycled air duct introducing 90% return air.
Looking at the air handler schematic, we need to circulate 200,000 CFM through the building to handle the design load. On the supply side we have: outside air intake at 10% of the supply air; a filter; a heating coil; a cooling coil; and a 210 HP supply fan. On the return side we have a 40 HP return air fan.
With only 10% outside air introduced into the system. This leaves potentially virus-laden air to recycle throughout the building. To make our office building safer by doubling the amount of ventilation, from 17 CFM per person to 34 CFM per person, the air handling equipment might need to be upsized and extra costs will be incurred.
An extra 167 Tons would be required to satisfy the load. Using the same cost structure as before, we have a new annual operating cost of $440,000 or an increase of $80,000 per year.
The mechanical system would look the same as shown in Figure 2, except the exhausted and fresh ventilation air is doubled and the return air is dropped to 80%. The same HP fans would be in place to circulate the air.
HYDRONIC RETROFIT
Now to the hydronic retrofit solution using chilled beams. Again, we are trying to make this building safer by doubling the current ventilation standards but also effectively reducing the operating costs. Is this even possible?
First, we will rely on the much more efficient distribution options with hydronics versus air. Just a reminder: 1 ton of sensible cooling (1,200 Btu/h) requires 550 CFM of air through a 10in x 12-in. duct, while that same 1,200 Btu/h can be achieved by 2.4 gallons per minute (GPM) of water through a ¾-in. diameter water pipe.
In our same sample building, instead of the air handler treating 100% of the load we decouple it and replace the air handler with the DOAS. We treat just the latent load, which means only 40,000 CFM total for the entire building based on the doubled ventilation requirement (see Figure 3).
The air is moved to the occupied space and then exhausted from the building meaning no air is recycled (no return air) and hence no virus-laden air is re-introduced into other occupied spaces.
Applying the chilled beam injection pumping system (one pipe primary/ secondary with local mixing) will provide the increased ventilation we are seeking along with lower annual operational costs with savings of $90,000 due to the reduced fan energy.
The sensible load is conveyed to the spaces via hydronics using a single pipe distribution system with local mixing per active chilled beam zone for temperature and humidity control.
A run-around loop is used to extract heat from the exhausted air and capturing this energy as first source for the incoming ventilation load.
As mentioned throughout these two articles, a chilled beam can offer significant energy savings. In Figure 4 we see the air system’s energy profile. The energy required to generate the Btus to satisfy the loads is 55% of the overall required energy. The balance (45%) is used to distribute the Btus.
A conventional chilled beam system decouples the loads, transporting the sensible load via hydronics reduces the fan horsepower required. While
Figure 3. A dedicated outdoor air system (DOAS)
Figure 4. Operational savings of DOAS/chilled beam versus VAV.
some of this HP now shifts to pumps, the total savings can be significant.
Chilled Beams are really the way to go in my opinion, and I expect this segment within our industry will grow. Seems to be a no brainer for any new building design, but this solution should also be considered for retrofit applications as well.
I hope these articles at least inspired some additional thoughts. All buildings need to become safer indoor environments. This is where the fight against any future pandemic should begin. <>
Mike Miller is VP Sales Canada, Taco Comfort Solutions and is a past president of Canadian Hydronics Council. Email: hydronicsmike@tacocomfort.com.
PLASTIC PIPE SIZING
HPAC Magazine spoke with Lance MacNevin to break down the sizing challenges with plastic pressure piping for commercial applications.
BY LOGAN CASWELL
This edition of 30 Mechanical Minutes featured a conversion between HPAC Editor, Doug Picklyk (left) and Lance MacNevin (right) from the Plastics Pipe Institute. MacNevin shared some history of plastic piping along with sizing tips for commercial applications.
On April 20th HPAC Magazine hosted the latest edition of 30 Mechanical Minutes, the free webinar series featuring virtual content for real world professionals. This edition zeroed in on plastic pressure piping in commercial plumbing, with a focus on the growing adoption of plastic pipes and sizing issues when it comes to design for plumbing and heating applications.
The guest for this episode was Lance MacNevin, a frequent contributor to HPAC and the director of engineering with the building and construction division of the Plastics Pipe Institute. This edition was sponsored by IPEX.
HISTORY LESSON
To begin, MacNevin shared some background on the early history of plastic piping in the construction industry, which dates back to the 1950s. The earliest residential installations of CPVC plumbing pipes was in 1959, and early-stage development of PEX piping was introduced in the1960s, with fullscale production hitting the European market in 1972 and really taking off in Canada in the 1990s residentially, and then in the 2000s for commercial applications. Other materials like polypropylene and PE-RT piping were first developed in Europe in the 1980s and introduced in Canada in the 2000’s.
From a building code perspective, MacNevin shared that both CPVC and PEX have been in the Canadian National Building Code since the 1990s, and polypropylene was adopted in 1995, while PE-RT appears in the latest 2020 National Plumbing Code released this past March.
While most certified plastic pressure piping can be used for commercial systems, some materials are not available in the sizes required. For instance, PEX tubing is widely available in up to 2-in. diameter, while CPVC and polypropylene are made from ½-in. all the way up to 24-in. and 30-in. or even larger.
In the field, plumbers will typically choose CPVC or polypropylene (including PP-R and PP-RCT) piping for its rigid characteristics on straight run installations. An example would be the vertical risers in multi-story buildings and horizontal headers of a school or an apartment building or condo. The logic is that you don’t need flexibility along a riser or header, but you do need big pipes and big volume. Then when it comes to branching off to individual classrooms, bathrooms, apartments or hotel rooms, the more flexible PEX or PE-RT are the choice of installation professionals.
MacNevin notes that all of the piping approved by the code has pressure rating for continuous operation of 100 psi at 180F giving plumbing installers the ability to seamlessly choose where they want to use rigid piping and where they want to use flexible pressure piping.
SIZING PLASTIC PIPING
Clearing up some terminology, MacNevin then clarified sizing issues as tubing and pipe have dimensional differences worth explaining. “We call it all piping, but there actually are dimensional differences between tubing and pipe,” he says, and this applies to plastics and copper and steel piping as well. “Tubing” means the actual outside diameter (OD) is ⅛-in. larger than the nominal size, it’s also known as copper tube size (CTS). “Pipe” means the actual OD matches that of iron/steel pipe
of the same nominal size, iron pipe size (IPS). “So when people ask for a plastic pipe or plastic tubing they really should use the right wording to make sure they get what they’re hoping for.” He also adds that polypropylene generally follows the European metric dimensions.
When it comes to sizing piping correctly for plumbing and heating applications you need to know: 1) Required flow rate (GPM or l/min), 2) specific fluid type (water or perhaps a glycol mix for hydronics), 3) fluid temperature (which affects viscosity), 4) pipe type, inside diameter, and smoothness, and 5), pipe length and associated fittings.
Since going with rules of thumb are not recommended, MacNevin shared how designers calculate pressure loss, velocity and the Reynolds number, an industry standard used to predict whether the liquid as a laminar or turbulent flow.
The classic equation that is used by the industry for pressure loss calculations is the Darcy Welsbach equation. The Plastics Pipe Institute has a free online tool, the Plastic Pipe Design Calculator (PlasticPipeCalculator.com) which can be used for calculating pressure drop and head loss among other options.
Lance MacNevin demonstrated a typical calculation using the PPI Plastic Pipe Design Calculator.
MacNevin provided viewers a concise walkthrough, demonstrating the ability to select piping and sizing type, wall types, and pipe diameter. Additional parameters on the calculator include flow rate, pipe length, fluid type and average fluid temperature. Individual fittings can also be included, and then the online calculator does the work to reveal the resulting flow type (laminar or turbulent), pressure drop, head loss and velocity.
Pressure loss and velocity are the two main factors to be considered when sizing piping systems, says MacNevin. To reduce pumping costs and save energy, designers typically want to keep friction low, and they want to keep velocity down to mitigate noise and vibration.
And yet stagnation for potable water is always a concern so you want to keep the water moving. Oversizing piping systems
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can lead to cost over runs and increased installation costs. Using the calculator, designers can try out different piping scenarios to find the right fit.
THE REYNOLDS NUMBER
Also, for hydronic heating applications there is the very specific purpose of optimizing heat transfer through the wall of the pipe that’s located within a floor or encased in concrete outside in a snow and ice melt tubing system. For these applications a minimum fluid velocity is important for optimal heat transfer to encourage a turbulent flow. “You want the water moving fast enough so that it’s always mixing and you don't get any slow-moving boundary layers of water inside the pipe wall (laminar flow).
To predict the velocity profile and flow regime, the Reynolds Number is calculated to find that “just right” pipe size. As MacNevin explains, the process for pipe design and specification is iterative, with the benchmark Reynolds Number separating laminar flow and turbulent flow at around 2,300. Above 2,300, the Reynolds Number indicates turbulent flow regimes that will give decent heat transfer through the pipe wall.
There is also transitional flow, a rate between laminar and turbulent, but as MacNevin points out, with radiant heating in a floor for example, the 180-degree bends in the typical small diameter tubing include even more churning and turbulence to prevent laminar flow, and so most radiant and snow melt systems are getting good heat transfer, even if people didn't design it that way. Yet, taking the time to calculate the proper sizing and ensuring a turbulent flow will lead to better results.
“These are some of the factors that designers really should be thinking about when sizing pipes,” suggests MacNevin. “It's kind of like a Goldilocks situation, you don't want too much and you don't want too little, you have to find that middle ground and find the just-right perfect pipe. There's always an optimal pipe size for a situation, but it might take a little work to get there.”
MacNevin also outlined how the Plastics Pipe Institute (PPI) offers a suite of tools for specifiers, designers, distributors, and installers, from training presentations and technical reports to case studies and more: visit www.plasticpipe.org/ BuidingConstruction for more information. <>
To view this entire episode of 30 Mechanical Minutes, or see previous episodes, visit hpacmag.com/tech-pulse.
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