As inverter-driven mini-split technology gains HVAC market share by roughly 30 percent each year, it’s being embraced in even the unlikeliest of places. Eastern Indiana is home to a growing Amish community, where members are drawn to the rural surroundings and the opportunity to continue the farming lifestyle that they’re known for. Sticking close to Read more
As inverter-driven mini-split technology gains HVAC market share by roughly 30 percent each year, it’s being embraced in even the unlikeliest of places.
Eastern Indiana is home to a growing Amish community, where members are drawn to the rural surroundings and the opportunity to continue the farming lifestyle that they’re known for. Sticking close to the land, however, doesn’t necessarily mean being uncomfortable or utilizing old technology. At least not anymore.
One Amish couple found a creative way to ease the rigors of harsh Indiana weather: humid summers and severe winter conditions.
Tom Neuenschwander, owner of Cardinal Air and Mechanical, in Linn Grove, IN, received an inquiry this past spring about replacing a window air conditioning unit with a mini-split at an Amish farm. AC was priority, but the homeowner also wanted to use the system as a source of heat. The most interesting facet of the conversation was that the home is entirely off-grid, using an existing 12 kWh photovoltaic solar array and 24V, 450 AH battery bank as its sole source of electric power.
Neuenschwander founded Cardinal Air in early 2020, and has already grown the full-service mechanical company to seven employees. Having worked in the HVAC field since he graduated high school, he knew that mini-split installations would provide an area of rapid growth, and has made ductless systems a focus since the beginning.
“We buy Fujitsu mini-spits through Chris Smith at Plumbers Supply Company in Fort Wayne,” said Neuenschwander. “He helped us find the right size Halcyon unit for this application, given the unique nature of the power supply.”
The two-story, 2,000-square-foot home was originally heated by a coal stove and cooled, partially, by a 6,000 BTU window air conditioner. A larger or second window unit couldn’t be used because the solar array and battery bank isn’t sufficient to handle a bigger load. The owners wanted to learn if they could improve their cooling performance with a mini-split, without the need to increase solar capacity.
“We had to size the mini-split to the source of power, not to the cooling load of the home,” said Neuenschwander. “In addition to the window unit, the small solar array powers a freezer, refrigerator, and a few lights. Domestic hot water is produced by a propane-fired tank.”
“Our biggest consideration was wattage draw,” he explained. When we looked at the Fujitsu specs, we found that peak draw from a 9,000 BTU Halcyon system on start-up is about 1,300 watts. The same system idles at 300-400 watts, with high draws around 600 watts. The battery bank could supply enough power to cover a 9,000 BTU unit, but not a 12,000 BTU system.”
When Cardinal Air purchased the system, they ordered a 115v model to match the transformer on the farm. Otherwise, the installation was quite ordinary. Cardinal Air standardized on Fujitsu as their brand of choice due to ease and simplicity of installation.
After having the unit in operation through all of summer 2022, the owners reported that the new mini-split cools the entire downstairs, instead of the one large room that the window unit used to serve. Beyond that, the mini-split uses substantially less power than the window unit, despite its 34 percent greater capacity. This becomes evident when numerous, consecutive cloudy days prevent good solar harvest.
“The homeowners reported that the mini-split now runs non-stop, whereas the window unit would deplete the battery bank after a day or two of cloudy weather,” said Neuenschwander. “It’s energy efficient enough at idle that it barely places a draw on the batteries. They’re cooling about 600 square feet with it. The only downstairs room that doesn’t quite stay at temperature is the kitchen, due to the floorplan. The humidity is gone, though. Oh, and the unit is a lot quieter than the window unit.”
“Because the system is sized to the power supply and not the heat load of the home, the owners know they’ll need supplementary heat,” continued Neuenschwander. “At this point, they just don’t know at what outdoor ambient temperature that will occur. So far, they say that the mini-split sure beats starting a fire in the stove to knock out the shoulder season chill.”
The owners have no plans to expand the solar array, but are considering expanding the battery bank and potentially installing a Fujitsu unit upstairs. For now, they’re thrilled with the comfort improvements and energy savings they’ve made to their off-grid residence.
Propane provides a versatile, efficient water heating solution for any size building Water heating can account for up to a quarter of all energy use in some commercial buildings. And because nearly 80 percent of water heating energy use occurs in buildings built before 2000, replacing outdated systems with newer, high-efficiency water heating technology can Read more
Propane provides a versatile, efficient water heating solution for any size building
Water heating can account for up to a quarter of all energy use in some commercial buildings. And because nearly 80 percent of water heating energy use occurs in buildings built before 2000, replacing outdated systems with newer, high-efficiency water heating technology can offer significant improvements in terms of performance and savings.
Water heating systems can be powered by a variety of energy sources, but many contractors are finding high-efficiency propane tankless water heaters to be the best solution. These compact water heaters provide a versatile, sustainable, and energy-efficient solution for many commercial applications.
Tankless propane water heaters only heat water when it’s needed, making a storage tank unnecessary and eliminating standby losses associated with maintaining a tank of hot water. Thanks to their compact, space-saving design, tankless units free up valuable square footage in commercial buildings and cramped mechanical rooms. Because they don’t require a bulky storage tank, units can be wall-mounted, free-standing, or even moved outside. Plus, tankless units are less labor-intensive to install than tank-style units or boilers.
As contractors seek the best water heating solution for their commercial customers, here are three key advantages of propane systems they should know:
Propane tankless water heaters can meet the needs of any commercial building.
Propane tankless water heaters offer a versatile, high-performance water heating solution—whether in a new project, as a replacement for an existing storage tank, or a boiler system.
One of the biggest benefits of this tankless technology in commercial applications is its flexibility to meet a wide range of load types. Propane systems can provide water heating for a variety of commercial applications including restaurants, multifamily residences, hospitals, laundromats, salons, health clubs, educational facilities, and hotels. Individual tankless units can meet the demand of many small commercial building applications and in high-demand commercial applications—such as hotels and restaurants where users need high flow rates, high temperatures, or both. Multiple units can be banked together in larger groups to provide a high-value design solution or even use a single unit with multiple heat exchangers delivering up to 3 million BTU/hr.
Most importantly, propane is a winning solution in buildings without access to natural gas—which is especially beneficial for resorts and lodging facilities that are oftentimes located well off the natural gas line.
Propane water heating offer significant cost savings and superior energy efficiency.
The occupancy and use of many commercial buildings may change over time, but energy efficiency and cost savings will remain key considerations. Propane water heating technology offers a long lifespan, competitive operational costs, and a lower total cost of ownership compared with other options.
The trend toward energy efficiency and zero net energy buildings isn’t slowing down. Now more than ever, commercial building owners are emphasizing energy efficiency, and they’re seeking products and designs that will support their efforts.
One of the most important benefits propane tankless units offer building owners and operators is energy-efficient operation and subsequent cost savings. Propane tankless units have efficiency ratings of up to 98 percent, these systems feature a condensing design that extracts additional thermal energy from combustion gases to heat incoming water.
Commercial operations have experienced significant cost savings after switching to propane. Notably, a Nebraska brewery, Bolo Beer Company, decreased its operating costs by more than 25 percent by using propane water heaters instead of electric water heaters. Ruby’s Inn, a resort in Utah’s Bryce Canyon National Park, is saving approximately $6,000 a month installing a system of propane tankless water heaters.
Beyond their noteworthy efficiency ratings, propane tankless systems can function for up to 20 years or more strengthening their value proposition in commercial applications. High-efficiency propane tankless water heaters also offer attractive paybacks, better reliability, and long-term energy savings—all helping offset higher initial capital costs. And planning your retrofit away from electric water heating to propane tankless water heating can save all the costs associated with emergency replacements and damage that can occur when storage tanks fail.
Propane tankless units help reduce a building’s carbon footprint.
In addition to decreasing energy consumption and costs, propane systems can make buildings more sustainable. According to data from the Propane Education & Research Council (PERC), propane tankless water heaters produce up to 47 percent fewer nitrogen oxide (NOx) emissions, 61 percent fewer greenhouse gas emissions, and 91 percent fewer sulfur oxide (SOx) emissions than electric storage tank water heaters powered by grid supplied electricity.
Switching from an electric storage tank water heater to a propane tankless water heater can prevent more than one ton of greenhouse gas emissions from entering the atmosphere each year—the same amount produced from driving a car more than 3,000 miles.
Water heating continues to be a major energy consumer in commercial buildings. Whether seeking increased energy efficiency, better performance, or a smaller carbon footprint, building owners can rely on propane to deliver a sustainable water heating solution in any size building.
To learn more about the benefits of commercial tankless systems, visit Propane.com/Water-Heating.
Bryan Cordill is the director of residential and commercial business development at the Propane Education & Research Council. He can be reached at email@example.com.
PEX Protects Pedestrians and High-End Flooring At City’s Prestigious Place Ville Marie Every winter in Montreal, an army of municipal employees works around the clock, running one of the largest snow-removal operations in the world. Up to 3,000 personnel and 1,000 snowplows are mobilized to collect 300,000 truckloads of snow from 10,000 kilometers of city Read more
PEX Protects Pedestrians and High-End Flooring At City’s Prestigious Place Ville Marie
Every winter in Montreal, an army of municipal employees works around the clock, running one of the largest snow-removal operations in the world. Up to 3,000 personnel and 1,000 snowplows are mobilized to collect 300,000 truckloads of snow from 10,000 kilometers of city streets.
The volume of material is almost as impressive as the means in which it is gathered and disposed of — snow removal in Montreal is carried out with military-like precision. And in Montreal they don’t just plow the streets. They also plow the sidewalks. When Montrealers talk about snow removal, they mean getting rid of it, not just pushing it to the side of the road. Here’s how it works:
When significant snow is forecast, signs go up announcing on-street parking bans. The day of the event, tow trucks cruise the streets blaring a warning to vehicle owners still parked in snow-clearing zones. If the cars aren’t removed within minutes, they are towed. Snow is then plowed to the center of the street, where a giant snow blower sprays it into a truck, which transports the snow to one of the city’s 29 snow dumps. A convoy of dump trucks repeats the procedure.
This well-run system is required in a city known not only for its Stanley Cup-winning hockey franchise, the Montreal Canadiens (known to locals as “The Habs”), but its brutal winters. Sometimes, however, it just isn’t possible to use a mechanized army of plows and shovels.
Severe winters are etched into the memories of Montrealers, when large accumulations of snow and ice combined with high winds have destroyed power lines, leaving some areas without electricity for days and residents dying.
A particularly nasty cold spell occurred in 2015, when for 12 days straight, temperatures plunged below -20 Celsius, making it the coldest February in Montreal in more than 100 years.
Fortunately, the modernization of the city’s downtown has brought with it the construction of areas where Montreal inhabitants can go to enjoy a pedestrian experience free of snow and ice. One of those is Place Ville Marie (PVM), a large skyscraper and shopping complex. Its four towers and spacious Esplanade is a nexus for Montreal’s underground city, with indoor access to over 1,600 businesses, several subway stations, a suburban transportation terminal and tunnels extending throughout the downtown.
Designed by Henry Cobb, of award-winning New York architectural firm Pei Cobb Freed & Partners, Place Ville Marie was built in 1962 to serve as the official headquarters of the Royal Bank of Canada, which it remains today.
According to design historian Mark Pimlott, via Wikipedia, “The most radical aspect of the Place Ville Marie project was that nearly one-half of its 280,000 square meters area were beneath street level, deriving the obvious benefit of being protected from Montreal’s extreme winter and summer climate.”
At time of construction, the main tower was the tallest in the British Commonwealth and the third highest skyscraper on Earth outside the United States. As for its moniker, former Montreal mayor Jean Drapeau reportedly chose Place Ville Marie for the name of the Catholic colony founded by what is now Montreal in 1642.
Fast forward to 2017 when Place Ville Marie received a make-over thanks to real estate firm Ivanhoe Cambridge, whose $1 billion Projet Nouveau-Centre featured plans to refurbish its flagship downtown properties, including PVM, Fairmont The Queen Elizabeth Hotel, Maison Manuvie, and Montreal Eaton Centre.
A $200 million investment revitalized the Esplanade (the central public space between the office buildings) and renewed the commercial offerings at Place Ville Marie. To execute the historic project, Ivanhoe Cambridge called upon Montreal firms Sid Lee Architecture and Menkès Shooner Dagenais Létourneux Architectes.
“Our primary goal is for this civic space to be a catalyst for downtown social activity,” Jean Pelland, architect and senior partner, Sid Lee Architecture, said at the time. “Given the importance of this iconic space, we sought additional exposure to urban activity, making it more accessible and usable. Our major architectural interventions are in line with this desire for great openness.”
An important part of the project’s ethos to breathe new life into the area, and position it as a social, cultural, and commercial hub, was to install a snow and ice removal system.
The restricted access for snow removal equipment, coupled with the upscale finish of the surface material, made mechanical and chemical snow removal at Place Ville Marie unfeasible. The owners turned to HeatLink Group, Inc. (Calgary, Alberta), a manufacturer and supplier of radiant hydronic heating/cooling and snow melt systems, to spec the job and supply the PEX-a tubing, loops and manifolds.
The Calgary-based company’s PEX-a snow and ice melt system eliminates the need for those other methods, helps to preserve the manufactured stone finish without abrasion caused by shovels or chemical attack from salt, and ensures pedestrians can safely and comfortably enjoy the space and use the stairs at any time of day or night in the wintertime.
At 120,000 square feet that would need nearly 50 miles of PEX-a tubing, the Esplanade at Place Ville Marie was the largest snow and ice melt project HeatLink had ever contemplated, certainly on par with the radiant heating/cooling system the company designed for the Vancouver Convention Centre. The six-floor facility is a global hub for conferences and trade shows; in 2010 it was used to host the medal ceremonies for the Winter Olympics. Place Ville Marie is comprised of pedestrian areas, stairs, and multiple levels of commercial space, incorporating a beautiful glass-roofed pavilion in the center.
The company worked closely with its distributor, Agence Jacques Desjardins Inc., and engineer Bouthillette Parizeau, to manufacture and supply 260,000 linear feet (79,300 m) of ¾-inch PEX-a tubing that was installed in 679 circuits or loops. A challenging aspect of this outdoor project was where to place the 77 supply and return manifolds, which distribute the heated fluid with 50 percent glycol solution to the numerous zones set up for snow melting. The 13-phase endeavor is the largest snow melt project in Montreal and ranks as one of the most extensive on the continent, according to the Plastics Pipe Institute, Inc., the major North American trade association representing the plastic pipe industry.
“The first hydronic snow and ice melting systems were installed in the 1930s using steel piping that was welded together and encased within concrete,” explained Lance MacNevin, P. Eng., director of engineering for PPI’s Building & Construction Division. “Those systems performed well and proved the concept, although the piping would start to fail after several years due to corrosion.”
Today, the majority of SIM systems utilize PEX – crosslinked polyethylene or PERT – Polyethylene of Raised Temperature resistance tubing. The PEX tubing used in this project is a flexible piping material with high temperature and pressure capabilities and incredible toughness.
“Hydronic SIM systems using fluid-filled pipes are known worldwide for their high degree of safety and convenience. Additional benefits include reduced liability, lower maintenance costs and long-term reliability, all important factors for building owners. Hydronic systems typically use far less energy to simply melt snow and let it flow down the storm drain than would be required to plow the snow and truck it away. Plus, because melting snow and ice prevents the need for salting and sanding, there is very low environmental impact, which fits in very nicely to Montreal’s sustainable development plan.”
The large surface area required thoughtful placement of manifolds to ensure efficient use of energy and tubing. The project used cleverly designed sliding panels to hide, protect and access manifolds that needed to be located close to pedestrian areas.
Manifolds ranged from four loops to 20 loops. In a couple of areas, two manifolds had to be joined together. “Snow melting systems require relatively high flow rates of heated antifreeze, as compared with indoor radiant heating systems, due to the energy requirements for melting snow during extreme weather events,” said Byron Stadnyk, HeatLink Group’s senior tech & design support. “Therefore, the tubing design has to allow for precise delivery of the heated fluid where it is needed, without incurring excessive pressure losses. There are engineering limits on how long the loops can be.”
All parties involved in the installation needed to make sure that the tubing loops followed the design specifications for on-center spacing, tubing patterns and circuit lengths. The nominal ¾ inch tubes at Place Ville Marie are spaced six inches (15 cm) apart. The project was designed to deliver a heat output of up to 150 Btu/h-sq.ft.
“You don’t want little piles of snow in between your loops, so adequate tube spacing is critical. The loop length has to be under a certain amount to make sure that selected circulator pumps can be used to efficiently deliver flow to all the areas as needed,” noted Mike Casavant, HeatLink’s technical manager. “There are a lot of technical constraints that people don’t even realize, that make a big, complicated project like this even more complicated.”
The tubing was positioned in a bed of leveling sand. It’s vital that the entire substrate be heated, along with the surface material, which at Place Ville Marie, consists of two-inch-thick manufactured stone.
“The challenge is to heat up the sand enough to be able to heat up the stone, to have high enough temperature at the surface to melt snow,” said Stadnyk.
The water-glycol supply is heated to 134 Fahrenheit (57 degrees Celsius) and pumped and distributed through the loops and manifolds to reach all of the heated areas. When snow begins to accumulate, sensors embedded in the surface stone activate the snow melting system. The heat sources are non-dedicated boilers that also heat the buildings.
With 260,000 linear feet of tubing installed underneath a finished-stone slab, it is important that the material is able to withstand the countless cycles of heating and cooling; nobody wants to be conducting an excavation to repair cracked tubing in the heart of downtown Montreal in the dead of winter. “The proven performance of HeatLink’s PEX-a tubing will ensure that such issues will not occur,” MacNevin stated.
A tekmar® Snow Melt Control 680 unit communicates with the building’s automation systems using BACnet® – the data communications protocol for building automation and control to provide alert notification, remote monitoring and adjustments. It uses sixteen tekmar Snow/Ice 090 Sensors to automatically detect snow or ice on the snow melting slab and meet demand on a priority basis.
According to PPI, PEX is a polyethylene material which has undergone a change in molecular structure using a chemical or a physical process whereby the polymer chains are chemically linked. Crosslinking of polyethylene into PEX for tubing results in improved properties such as elevated temperature strength and performance, chemical resistance and resistance to slow crack growth.
Casavant compares PEX tubing to the tires on a car. “A long time ago tires were just natural rubber and they would fall apart in short time. Charles Goodyear discovered that if he crosslinked the rubber through “vulcanization”, the modified rubber would resist the abuse of the roads and last much longer,” he said. “Standard thermoplastic materials can be heated and reformed into various shapes. Crosslinked polyethylene doesn’t do that. Once you’ve extruded the material into tubing, if you try to do anything to it, short of grinding it, it will always stay in the shape of that piece of tubing. You could heat it up and tie it into a knot, and you could even undo it, it’ll still be a piece of tubing. As long as you don’t cut the tubing, it will always hold its shape.”
The industry states that PEX tubing has an expected design life in excess of 50 years for projects such as this one.
“The success of the snow removal system at Place Ville Marie should encourage other engineers and architects to consider hydronic SIM systems for large public spaces, especially in downtown urban areas,” MacNevin stated.
“I think the more people realize that a job of that scale can be done, they’re not going to be afraid of it,” Stadnyk said.
“The high visibility and usage of this area will highlight the benefits of snow melt systems, not only to knowledgeable professionals in the heating industry, but also to the general public who will appreciate how accessible this space is in the winter. In the plastic pipe industry, our products and their benefits are largely invisible to the casual user, but in this case, people will notice immediately when they step from the snowy city sidewalk onto the PVM property,” said Casavant.
“It’s one thing to see a driveway being snow-melted, but it’s a very different thing to see this huge promenade where people are literally walking onto it from the city sidewalk, kicking the snow off of their boots and they don’t have to worry about slipping and sliding on the steps because the steps are all melted. I think they’re going to see that and say, ‘I love taking this route because of these reasons.’”
More information about SIM systems plus technical information can be found at the PPI Building & Construction Division’s website: https://plasticpipe.org/BuildingConstruction
Michigan’s High Mountain Cannabis Co. mold and fungus prevention efforts lead to rich harvests Mold and fungus is one of the most pressing issues facing the North American cannabis growing industry. Fungus and molds, such as Botrytis, are leading causes of infections that can result in entire crop destruction and sometimes even force cannabis grow-op Read more
Michigan’s High Mountain Cannabis Co. mold and fungus prevention efforts lead to rich harvests
Mold and fungus is one of the most pressing issues facing the North American cannabis growing industry.
Fungus and molds, such as Botrytis, are leading causes of infections that can result in entire crop destruction and sometimes even force cannabis grow-op closure for weeks of remediation.
However, cannabis growers are fighting back by combating mold, fungus and other microorganisms with ultraviolet germicidal irradiation (UVGI). Cannabis grow-ops are specifically using the UV-C wavelength, which is lethal for mold, bacteria, viruses and other biological contaminants.
UV isn’t new as it has been used for more than a century to sanitize water. More recently, the HVAC industry has developed UV lamp kits for HVAC systems to prevent mold and biofilm growth inside air handler units and to neutralize airborne microorganisms as they circulate through the ventilation system.
Consequently, cannabis growers have increasingly installed UV-C germicidal lamp systems in their facilities’ air handlers. One example is High Mountain LLC, Vassar, MI, an 8,500-square-foot facility that relies on UV-C lamps in its HVAC air handlers to prevent mold and fungus contamination.
The UV-C systems, combined with tight HVAC humidity/temperature control, help grow rooms operate at sanitary levels similar to cleanrooms. High Mountain’s impressive harvests are typically three-lbs/1,000 watt light (or a minimum 100-lbs/50-light room), which is considered the high end of the productivity scale in Michigan.
Based on previous mold suppression efforts, COO/co-founder Brandon Schmitzer, plans UV-C lights for an upcoming 10,000-square-foot expansion in the wake of the facility’s addition of recreational use certification to its original 2020 medical marijuana certificate from Michigan’s Marijuana Regulatory Agency (MRA).
“Mold is a constant battle in the medical marijuana growing industry, because it’s critical to keep (microbial) colony-forming units under the strict government standards we must meet during test processes,” said Schmitzer. “UV-C is an important part of the puzzle in keeping a facility sanitary.”
Consequently, High Mountain hasn’t encountered the mold challenges other Michigan grow-ops have faced, such as remediation, harvest delaying re-testing/inspection and, in some extreme cases, crop destruction.
Schmitzer and his HVAC contractor, Martin Proctor, president, Proctor Plumbing LLC, Vassar, chose APCO-X, a combination of UV-C disinfection technology and activated EverCarbon™ media catalyst air treatment for HVAC systems. Manufactured by Fresh-Aire UV, Jupiter, Fla., the APCO-X units were strategically placed in air handler return ductwork between the air filter and coil to prevent mold and biofilm growth on both. The UV-C light also neutralizes airborne mold and microorganisms in the airstream. While UV-C addresses biological contaminants, the APCO-X V-Twin EverCarbon Matrix is infused with lifetime warrantied activated carbon media to adsorb volatile organic compounds (VOC). VOCs, such as material off-gassing, solvents and glues, cleaning chemicals, and general nuisance odors are removed from the airstream before grow room HVAC distribution. The EverCarbon Matrix includes an antimicrobial-coating. The APCO-X process does not introduce any additives or oxidizers into the air that may pose issues to occupants or plants.
The facility operates 22 HVAC split systems ranging from 2 tons to 5-ton, 2,000-CFM units manufactured by Goodman Air Conditioning and Heating, Waller, Texas. The three flower rooms operate six 5-ton units each with air distributed through fabric ductwork manufactured by FabricAir, Suwanee, GA. The, Combi 70 fabric duct employs an anti-microbial agent that also helps prevent surface biological growth.
The ductwork distributes air evenly through Oriflow orifice arrays that span linearly along the entire length at 5 and 7 o’clock positions. Approximately 15-percent of the air circulates through the fabric surface. This promotes uniform airflow and prevents condensation formation, which helps in facility moisture control.
Other equipment critical to High Mountain’s mechanical design includes 210-pint/day dehumidifiers and 34.6-gallon/day steam humidifiers manufactured by Anden, Madison, WI, to maintain relative humidity levels.
Preventing biological contaminants with UV-C also has an additional benefit of maintaining optimum HVAC system efficiency and cleaner air. A biofilm coating as thin as 0.002-inches can potentially reduce HVAC coil energy efficiency by up to 37%.
“We’ve been manufacturing coil and duct mount UV disinfection systems for more than 20 years for all types of building applications,” said Aaron Engel, vice-president of business development, Fresh-Aire UV. “For example, healthcare facilities employ UVC disinfection to address hospital associated infections (HAIs). Grow facilities are no different, except they’re mitigating cross-infection of plants within the facility as well as disinfecting the HVAC equipment which can introduce mold and fungus into the facility. Germs are germs. What’s important is applying the right strategy and product for the application.”
High Mountain’s five-year plan includes a goal of 10 more buildings, dependent on power availability. Regardless of the number of buildings, all HVAC systems will definitely be using UV-C to prevent mold and mildew growth on and around the cannabis plants, according to Schmitzer.
Engineer’s ERV static-plate enthalpy cores specification eliminates need for conventional defrost systems and saves city energy and maintenance costs The new $12 million Wasilla (Alaska) Police Station employs many innovative HVAC designs that will save the city energy and provide occupants with unprecedented indoor air quality (IAQ). The recently completed 20,000-square-foot building designed with aesthetic Read more
Engineer’s ERV static-plate enthalpy cores specification eliminates need for conventional defrost systems and saves city energy and maintenance costs
The new $12 million Wasilla (Alaska) Police Station employs many innovative HVAC designs that will save the city energy and provide occupants with unprecedented indoor air quality (IAQ).
The recently completed 20,000-square-foot building designed with aesthetic post-modern industrial architecture by MCG Explore Design, Anchorage, doubles the police department’s previous building, which was an old, converted bank. The sustainable mechanical HVAC design features dedicated outdoor air systems (DOAS) with energy recovery, hydronic radiant floor heating and packaged rooftop units (RTU) with heat recovery that all contribute to energy efficiency.
For example, ERVs were specified without defrost coils, which are commonly used for Alaska’s frigid winters, but are costly in upfront capital, operational and maintenance costs. Instead, DN Series DOAS units manufactured by RenewAire, Waunakee, Wis., use static-plate enthalpy cores. The units are designed to operate down to -10°F ambient temperatures without requiring defrost cycles, because they don’t transfer H2O between supply and exhaust air. If temperatures drop lower (Wasilla temperatures rarely drop below -20°F), the DN-Series’ onboard controller activates a bypass damper and introduces space heat to prevent heat exchanger frost accumulation, if needed, according to Christian Dougherty, P.E., mechanical engineer and the project’s manager at consulting MEP engineering firm, AMC Engineers, Anchorage, Alaska.
“The energy recovered by the DOAS units, and the fact they don’t require conventional defrost cycles and equipment, is saving the city a large amount of money,” said Dougherty, whose firm has specified core-based units on previous projects. “We’ve had mixed results in the past with energy recovery alternatives, such as enthalpy wheels, that require defrost cycles and maintenance for moving parts that cores don’t require.”
“Cores aren’t subject to cross contamination, which is potentially problematic in critical spaces, such as garages and evidence rooms, where contaminants can potentially infiltrate occupied spaces,” added Jordan Privoznik, systems sales leader at Trane, Anchorage, Alaska. “DOAS units with static-plate cores are often an ideal solution in our environment as they can be more reliable than other energy recovery methodologies due to less moving parts, while still achieving very high efficiencies.”
Installed by project mechanical contractor Mechanical Specialists Inc., Wasilla, Alaska, the two DN Series ERVs provide 3,000-CFM and 1,700-CFM of 100% outdoor air in the facility’s 3,100-square-foot garage and the 750-square-foot evidence room, respectively. Both spaces are under negative pressure to prevent garage vehicle emissions and evidence room odors, such as bodily fluids or confiscated drug off-gassing, from infiltrating common walls shared with occupied spaces. The two units are also outfitted with sensors, an onboard controller, a manual wall switch and a smoke detector, the latter which complies with Alaska building code. The facility’s building management system (BMS), a Trane Tracer Control System, monitors the ERVs.
While evidence material off-gassing was the prime motivation, 100% outdoor air will also dilute any airborne contaminants that could degrade stored evidence. The evidence room is also closely monitored to minimize any potential degradations from wide temperature and humidity variances.
The garage’s 100% outdoor air is critical in preventing CO and NO2 accumulation and maintaining indoor air quality for employees using and servicing city vehicles. The ERV uses energy recovery to help maintain a year-round 70°F set point. On extreme cold days, which according to ASHRAE guidelines is -23°F locally, the ERV can preheat air to as high as 40°F. A 70°F leaving air temperature can be reached on extreme days by using the integral hydronic reheat coil supplied by the boiler circuit’s glycol heat exchanger.
Other project equipment includes a 25-ton, 8,500-CFM Trane Intellipak™ RTU that supplies the building and includes DX cooling, hydronic heat, and variable airflow, serving several Trane variable air volume (VAV) boxes with hydronic reheat coils to provide precise zone control. A 15-ton, 5,000-CFM Trane Voyager™ RTU was also specified. Radiant floor heating, and snow melt duties are provided by a 2Mbh gas-fired boiler manufactured by Riello, Mississauga, Ontario. Secondary glycol heat exchangers for air handlers were provided by Bell & Gossett, Morton Grove, Ill.
Additional efficiency was created by a Dougherty and Privoznik collaboration that configured the radiant floor heating into zones (rooms) controlled by the Trane BACnet Building Automation System. While VAVs and radiant heating can operate concurrently, there exists a challenge when combining VAV technology’s quicker space comfort achievement with radiant tubing embedded in a thermal mass that takes longer to react. “Meticulous programming and strategic commissioning were required to ensure both systems operated seamlessly and synergistically,” explained Privoznik. “This process, combined with Trane’s advanced Trim and Respond control strategies as prescribed in ASHRAE Guideline 36, allowed us to maximize energy efficiency, maintain control stability and achieve optimal space comfort for the occupants.”
Another energy efficient design was Dougherty’s collaboration with Trane for designating one air handler for operation only during standard business hours, while the other unit operates for 24/7 occupied areas. When a large portion of the building is unoccupied, and outdoor air isn’t required, the less efficient VAV System is disabled and space temperature is maintained solely thru radiant floor heating.
Although the project didn’t apply for Leadership in Energy and Environmental Design (LEED®), Dougherty said the HVAC design would have significantly helped the building accumulate enough credits if the city had chosen certification.
Regardless, the police station is delivering 21st century comfort, IAQ and energy savings, within a strict construction budget.