Although COVID-19 may have highlighted issues regarding ventilation, careful HVAC system selection has always been crucial in educational settings. While there are several types of classroom air conditioner units, they work in different ways and have differing requirements for installation. This covers some of the basics about each type and their potential roles in a larger HVAC system.
While there are a number of HVAC options available, engineers have a baseline for assessing the systems that they design through three standards from the American Society of Heating, Refrigerating and Air Conditioning Engineers, or ASHRAE. For reference, ASHRAE 90.1 covers energy usage, 62.1 covers indoor air quality, and 55 covers thermal comfort in terms of both temperature and humidity.
Each has a number of requirements, but the ones most crucial to specifying engineers are the minimum efficiency, minimum ventilation rates for rooms based on activity and occupant load, and comfort zones. These must be used along with the available space, budget, and other factors to properly select the right classroom air conditioner units.
There are four main types of air conditioner units for classrooms, ranging from the venerable unit ventilator to variable refrigerant flow systems and two variable air options.
First introduced in 1917, unit ventilators (UVs) are the most commonly chosen and established way to bring fresh air into educational environments. A fan, run through a heating or cooling circuit, brings in outside air to meet the desired temperature. Because UVs function discretely (one unit per room), one room’s heating and cooling system can malfunction without affecting the rest of the building. Sometimes on a retrofit Job with Existing UV’s replacing like for like is the least costly alternative due to the fact UV’s have been around for so long and they haven't changed much over the years.
However, UVs are not without their drawbacks. They don’t affect the level of moisture in air, which means that students and educators are still impacted by seasonal drops and increases in humidity. Additionally, because they use a single unit to heat or cool a room, any blockage or issue significantly reduces a unit’s effectiveness.
Variable refrigerant flow systems operate on principles much like that of a heat pump. With the proper controls and piping, refrigerants can move around and into dozens of indoor units to provide heating and cooling without the need for large ducts or piping. While they are extremely efficient compared to other options, they may not be as great a fit for interior classrooms and spaces that require significant ventilation.
Single-zone variable air volume systems are increasingly common in educational settings. They can be quieter than unit ventilators because they can operate at significantly reduced fan and compressor speeds. This can also help with humidity control, especially during changes in occupancy levels. However, they also require ducting throughout individual classrooms and carry more of an initial cost.
As opposed to a single-zone system, a larger variable air flow system may also be able to provide heating, cooling, fresh air, and dehumidification to classrooms throughout a building. While this is less expensive in terms of both first and ongoing costs, there are key considerations. The system must be able to direct fresh air to spaces at varying rates depending on ventilation needs of windowed and non-windowed rooms. In addition, there must be enough space for the ducting to be able to bring fresh air into a classroom, not feasible for some retrofit projects.
Classrooms in schools can occupy any number of spaces, which can make for some real headaches when trying to establish proper temperature, humidity, and ventilation levels through system design. So, whether considering a major upgrade or as part of new construction, engineers must understand:
Windy City Ventures represents leading manufacturers of the systems above that serve as classroom air conditioner units and we understand how important it is to take multiple considerations like budget and existing systems into account when specifying these units. Contact us today for a quote or bid.
If you’ve ever designed a hydronic system, you’re probably familiar with the struggle of balancing simplicity and flexibility. Because hydronic systems use a closed system of pipes to circulate water through a building for heating or cooling, keeping the equipment used to power a hydronic system simple can help lower project costs. On the other hand, keeping residents comfortable across a spectrum of temperature and humidity conditions is a struggle with any system. So, is it worth it? Here’s a quick summary of considerations before you decide.
Ultimately, hydronic heating and cooling systems are significant initial investments—which makes funding a major short-term concern for building owners and managers. Engineers, however, focus on the long term. When they design a building’s HVAC system, they’re inclined to choose the most efficient equipment and layout that meets the facility’s budget.
Funding, for building and facility managers, is the ultimate struggle with a long-term capital investment like a hydronic heating system. For the specifying engineer, there are substantial benefits to using the most efficient boilers, multiple zones, and centrally controlled valves in terms of minimizing energy usage and maximizing occupant comfort.
Unfortunately, while it can be easy to map out the payback period for certain upgrades to an existing system, there is still the maximum budget to work with. This is particularly important when the specifying engineer may only be coming in after the project owner has agreed on initial budget constraints.
Currently, boilers for commercial operation face some of the least stringent efficiency requirements among HVAC systems on the market. The most common metric is annual fuel utilization efficiency (AFUE), and government regulations require a minimum AFUE of 80‒84 percent depending on whether the system uses steam or hot water and whether the system uses natural gas or heating oil. Note, some building codes require a new facility to meet ASHRAE 90.1 standards. If required, hydronic heating systems must have a return hot water temperature of 120 F or less. For boilers to accept 120 F return water, they must be of the condensing type. Condensing boilers are more efficient than non-condensing boilers.
There are obvious benefits to going with higher efficiency boilers, but to do so requires leveraging some different technologies. Condensing technology basically acts like a turbocharger in a car engine and uses exhaust heat to increase efficiency. With an AFUE of 93 percent or better, these are clearly more attractive on a lifecycle basis but are sometimes more expensive than standard or non-condensing options.
The heart of the hydronic heating system is the boiler but so much of the system’s energy consumption and first cost is contingent upon the selection and design of the building’s heating and air distribution strategy as well as the building envelope and purpose.
Building use, purpose, and physical constraints: When designing a hydronic system, one must consider how the heat is getting into the space. Will occupants be exposed to warm forced air, or will they be in line of sight with heating elements (radiators or radiant heating panels)? Both systems use heat exchangers where hot water is run through pipes in the building that feed heat transfer coils. These heat transfer coils must be sized to transfer enough BTUs to the space while allowing the return water temperature to be approximately 120 F or lower.
Older heating systems were designed so that the return hot water temperature was above 140 degrees Fahrenheit. The lower the return water temperature, the greater physical space required by the heating coil. If the building’s configuration or purpose cannot accommodate the space, then condensing operation will be challenging.
Hydronic system boilers and terminal devices: Hydronic heating equipment selection is a key part of the overall design. Installation, maintenance, and operating costs are all impacted by where the equipment can be installed. If it is inside a building, contractors should consider where in the building it will be located, and if it will be exposed or integrated into the building. As a rule, the more hidden the equipment, the more expensive the equipment.
Here at Windy City Representatives, we work with leading names in HVAC equipment. We understand how complex the planning, development, design, and construction of a hydronic system is for commercial buildings. Contact us today at 630-590-6933 for support.
The actual process of a commercial boiler is relatively simple: a heat source warms up water in a chamber and pushes it out into a commercial building where the hot water or steam provides sensible heat as it passes through radiators and other heat exchangers. But to explain how commercial boilers work, you must understand the various ways this is accomplished in modern systems.
A boiler includes a combustion chamber with a burner, a heat exchanger, and a chamber for the water. The heat exchanger can be produced using a variety of materials, including cast iron, carbon steel, stainless steel, or copper, all while keeping the water from coming into direct contact with the flame source.However, the system still needs several more components in order to operate safely, including:
There are myriad types of commercial boilers, which is one reason the explanation above is so brief. They vary drastically in size and are powered by either natural gas, fuel oil, biofuels, or electricity. You could also group commercial boilers based on whether the boiler system produces hot water or steam.To stick to the basics of a commercial boiler, however, you should focus on how the water in the system is heated by the combustion itself. In this case, there are two primary types of boiler:
In firetube boilers, the name explains the process: the combustion gases run through pipes that are surrounded by the water in a vessel. The hot water produced will be pumped through the system or the steam produced will be introduced into the steam distribution piping. They have significant benefits, as the capacity range is large, relatively affordable compared to other options, and have inexpensive replacement components. Additionally select firetube boilers that generate hot water can be designed for condensing operation and/or variable water flow operation. Both of these modes of operation allow for significant energy savings.
Watertube options are basically the opposite of firetube boilers. The tubes carry water, and they are surrounded by the hot gases produced by the burners. They can be more expensive, but can handle much higher pressures and can produce large quantities of steam (steam quantities for process or industrial use). The real question is what is required by the rest of the system.
Although condensing boilers can be configured as either firetubes or watertubes, they distinguish themselves because of a secondary process. Exhaust gases contain water vapor, and when the gases are run over a second heat exchanger, the water vapor in the combustion gas condenses and the energy associated with the phase change is transferred to hot water used in the system. While normal boilers may have efficiency ratings of 80-84 percent, condensing boilers have efficiency ratings well north of 90.
Windy City Representatives works with leading manufacturers of commercial boilers and related components, and we understand how important it is to take multiple considerations like budget and existing systems into account when planning and developing hydronic or steam systems commercial or industrial buildings. Call us today at 630-590-6933 to discuss your options.
Rooftop HVAC units (RTUs) are a popular choice among building engineers and managers. Although there are a wide variety of models available, most rooftop HVAC systems have a few things in common: they’re compact, conveniently placed, and reasonably simple to maintain. Not to mention, one single piece of equipment has the ability to heat, cool, filter, and ventilate a building’s air.Together with these common virtues, rooftop HVAC units are also prized for their versatility. Their design and location allow specifying engineers to tailor each building’s system according to its needs, including ventilation and noise control.
Of course, the measure of any HVAC system’s success is how much energy it can process. Units fall into several size categories—small, large, and very large. If you’re an engineer considering including a rooftop HVAC system in your building, knowing what these categories mean and how it could impact your HVAC design is critical.
While the Air-Conditioning, Heating and Refrigeration Institute measures performance and efficiency in British Thermal Units/hour (Btu/h), most manufacturers measure using “tons,” a reference to when actual tons of ice were used to cool facilities. (For reference, 1 ton of ice is roughly equivalent to 12,000 Btu/h. of cooling) So, a unit rated at 24,000 Btu/h, or 2 tons, could remove roughly 2 tons of heated air from the building every hour.Most rooftop HVAC units fall into three categories:
Many HVAC manufacturers have models that fall outside of the 5‒20-ton range. However, most industry and federal regulations are based on the sizes listed above.
After determining the size of your rooftop unit, you’ll have a few more choices to make.
As technology advanced, so too did the methods commercial rooftop HVAC manufacturers used to measure their equipment’s efficiency. For decades, HVAC equipment efficiency was measured using energy efficiency ratios, or EERs, which only track a system operating at 100% capacity. Most systems only operate at such a high capacity a few days a year—if that. EERs also didn’t take climate into account, which decreased the accuracy of EERs as a measurement. To address this inaccuracy, the seasonal EER, or SEER, was introduced.
Seasonal EERs rate units based on their performance across an entire season, providing a more balanced overview of a system’s efficiency.
However, this still did not address the problem of accurately measuring a large rooftop HVAC unit. Today, rooftop units are evaluated using integrated EERs, which calculate the system’s efficiency at different load levels and rate it accordingly.
If you’re replacing a large commercial building’s rooftop HVAC system, you’ll need to keep several important points in mind. Although you might be tempted to simply choose a system with the same specifications as the older model, we’d advise against it.
Instead, consider your building now—has its purpose changed since the last unit was installed? Do you need to bring in more OA for your occupants? For example, think of a warehouse that is now being converted into commercial office space. Chances are the current rooftop HVAC system wasn’t installed with the building’s new occupants in mind, and you’ll need a model that can handle a higher level of demand (comfort cooling and heating, more OA, and quieter operation)Regardless, be cautious. Rooftop HVAC unit installation is tricky: if your unit is too small, your building won’t be adequately heated or cooled. Even the installation process can prove problematic—without proper insulation and ductwork design, you might expose your occupants to excessive and unnecessary noise from the system.
Windy City Representatives works with leading manufacturers of commercial rooftop HVAC units. We understand how important it is to take multiple considerations like budget, existing systems, and ventilation needs into account. Call Windy City Representatives today at 630-590-6933 to discuss your options.
The human body can thrive in a variety of environments, but we tend to feel the most comfortable at certain temperatures and relative humidity levels. If the air we’re breathing is too dry, we start to tear up or cough. In pools and spas, we deal with breathing difficulties for the opposite reason—humidity in an indoor pool can get so dense that people have trouble breathing. However, normal HVAC systems just aren’t built to handle that much moisture. That’s where pool dehumidification units come in.
You may not see the point behind adding yet another component to your HVAC system. After all, you could just use your air-conditioning system to deal with the humidity in your pool or spa. In that case, you wouldn’t be entirely wrong. This would eliminate some of the major problems with excessive moisture, including bacteria and mold growth and damage to wood and metal.
However, you’d also have to run your cooling system constantly to keep the humidity down. Although it’s possible, you’d be putting unnecessary strain on your system, which means more breakdowns down the road, leading to higher utility and repair bills.Few environments put more stress on an HVAC system than an indoor pool or spa environment. It’s not just the moisture: water in pools and hot tubs has to be treated with harsh chemicals like chlorine which damage delicate AC components. Pool dehumidification units, on the other hand, are built to operate constantly in very warm, humid environments.
There are two commonly used designs for pool dehumidification units: refrigerant dehumidifiers and ventilation dehumidifiers. Generally, the type you choose will depend on the area you’re trying to dehumidify and your budget.
Refrigerant dehumidifiers are fairly simple. Humid air enters the system and passes over a very cold coil. Water from the air condenses from vapor into liquid before finally draining from the system.
Although they’re effective, refrigerant dehumidifiers have their disadvantages. Because the system’s fan and cooling coil must operate constantly to keep humidity levels down, they require a lot of energy to function at full capacity.
As the name implies, ventilation dehumidifiers take advantage of outside air to help manage relative humidity levels around indoor pools. Up to 100% of the inside air can be replaced with outdoor air, providing exceptional levels of moisture removal.
Ventilation dehumidifiers are more efficient and can be more cost-effective over time for high-volume, high-traffic spaces. However, since the system can only directly transfer moisture to outside air, it can’t function well when the outside air is more humid than the air coming from indoors or the outdoor air is too cold and must be heated. Finally, because they require more equipment—and room—than refrigerant dehumidifiers, they’re not ideal for small spaces.
Ventilation of pool spaces is also critical as the indoor air quality of a pool is difficult to manage. According to Dectron, a leading pool dehumidification equipment manufacturer, “It is a common misconception that a strong chlorine odor is caused by too much chlorine in the water. The odor is actually caused by chloramines (combined chlorines) off-gassing from the pool water surface. Chloramines are formed in the pool water when there is insufficient free chlorine in the pool to address the nitrogen-containing compounds brought into the pool water by the swimmers.” Exhausting air containing these chloramines and introducing clean outdoor air is critical.
If you’re buying a unit for a small pool or hot tub, you’ll probably want to go with a refrigerant dehumidifier. This type of dehumidifier is the smallest, most budget-friendly option. However, if you’re shopping for a large indoor space, you should consult with a professional to determine which type of dehumidifier will work best for your facility. No two spaces are alike, after all.
At Windy City Representatives, we work with custom equipment manufacturers to procure high-quality, affordable pool dehumidification units. These products are manufactured by Dectron and AAON. We’ll work with you to find the right fit for your needs and budget. Contact Windy City Representatives today
Radiant heat has been warming homes and buildings for hundreds—if not thousands—of years. Its cooling counterpart, the chilled beam system, has been around since 1986. Given those numbers, it’s no surprise that chilled beam cooling isn’t a common sight in American buildings today. But chilled beam cooling shares many of radiant heat’s benefits, and it’s worth considering if you’re in the market for a new air conditioning system. Here’s how it works and why we like it.
You can think of chilled beam systems as, well, radiant cooling. Chilled beam units are installed in ceilings where the cooling process begins with chilled water flowing through a coil in the system. Next, the cooled air mixes with the warm air rising from the ground. Finally, the pressure change caused by this motion creates a cyclical pathway, which pushes the treated air into a space. These units are called “passive chilled beams.”
Active chilled beams supplement this process by pushing conditioned air through a pressurized nozzle that creates an induction effect. Both versions are much quieter alternatives to forced-air, fan-driven AC systems.
Although active and passive chilled beam systems share a coil-driven cooling mechanism, passive chilled beams are best suited to spaces with existing ventilation systems (outside air is already introduced). Active chilled beams, on the other hand, require a conditioned outside air supply.
Because chilled beam systems are comparatively new, even seasoned HVAC professionals are less confident about their design, cost, and installation requirements. Here are responses to a few questions on installing and maintaining chilled beam systems.
1. Do chilled beam systems cost more than similar cooling systems?
A chilled beam system is almost always used in the active configuration, where outside ventilation air is introduced through the beam before entering a space. As a result, the air handlers that are already required for outside air requirements can be up to 75 percent smaller than mixed return air handling units. There are similarly smaller duct runs throughout the building.
2. Do chilled beam systems have condensation problems?
Actually, no. Modern HVAC systems have the ability to control chilled water temperatures and indoor humidity levels to ensure coil surface temperatures are above the space dewpoints. In fact, testing by manufacturers showed that droplets only began to fall more than 20 hours after the coil temperature had reached the dewpoint when systems operate out of setpoint.
3. Is it safe to install chilled beam panels near lighting, sprinklers, and sensors?
Yes. In fact, there is less thermal variability for this equipment when installed near a chilled beam system. Some manufacturers have even integrated electric cabling and fire safety equipment into the design of their chilled beam system units.
4. I’m interested. Is a chilled beam system a good fit for my building?
Maybe, and maybe not. At Windy City Representatives, we’ve helped design heating and cooling solutions for many buildings. No two designs have been identical—every building has slightly different needs, and every type of HVAC system has its own benefits and drawbacks.
If you’re interested in incorporating a chilled beam system into your building’s cooling system, contact Windy City Representatives today—we’ll work with you to find the right fit for your needs and budget.
Every few years, the U.S. Department of Energy (DOE) updates its guidelines regarding energy efficiency for a wide variety of products. If you work in commercial HVAC, you’re probably following the standards related to commercial HVAC efficiency requirements. Although there are a variety of standards, the most relevant ones in the commercial and industrial sector govern rooftop units (RTUs). These standards comprise at least half of all commercial heating and cooling systems and have the most impact on design and manufacturing improvements.
However, these requirements can be hard to navigate without the right knowledge.
On January 1, 2018, the DOE introduced updated efficiency requirements for rooftop HVAC units. As of January 1, 2023, the DOE will begin enforcing higher efficiency standards. Based on the DOE’s new requirements, RTUs made after 2023 must be 15 percent more energy-efficient than older models.
However, the new efficiency goals aren’t the most significant challenge manufacturers face. The fundamental challenge is how to measure that efficiency.
Until recently, the DOE measured split-system commercial HVAC energy solely by energy efficiency ratio, or EER. Put simply, EER measures the efficiency of a piece of HVAC equipment when it is operating at full load—during the hottest days of summer and coldest days of winter. The higher the EER rating, the more efficient a unit is considered during peak demand hours. This information may be useful, but it doesn’t accurately represent the energy efficiency of larger units for buildings with many occupants with different HVAC needs. The vast majority of operating hours of commercial HVAC equipment is spent running at less than full capacity. So a rating system that more accurately represents the real world of cooling operation is coming into place: IEER, or integrated energy efficiency rating.
Today, these larger pieces of HVAC equipment are also evaluated in terms of the integrated energy efficiency ratio, or IEER. As with EER ratings, the higher the IEER rating, the more efficient the unit.
However, IEER requires a different approach to measuring energy efficiency. Instead of judging a system solely by its performance at peak demand, IEER measures a system’s efficiency at various loads on a weighted basis. Essentially, it evaluates how well a system performs at different temperatures across wide-ranging conditions to provide a more accurate picture of overall system performance.
To meet these standards, HVAC manufacturers have responded in many innovative ways, including:
Although these features have been implemented in many other industries for years, HVAC manufacturers must incorporate them while still meeting existing size requirements for units. Moving forward, smaller AC and heating RTUs (units that require >65,000 to <135,000 Btus per hour to function, respectively) must maintain IEERs of at least 14.5 and 13.9, depending on their energy source. On the other end of the scale, very large AC and heat pump RTUs must maintain an IEER of at least 13 and 12.3, respectively. For a more detailed breakdown of these air conditioning and heat pump unit standards, see the table below.
Windy City Representatives works with leading manufacturers of rooftop units and other systems that are both efficient and durable. We look forward to working with you to find units that meet current DOE commercial HVAC efficiency standards and will help future-proof your project through 2023 and beyond. Contact us today to discuss the right units for your building.
“Crack open a window!” The idea that fresh outside air is important to people inside has been around since the first time that phrase was shouted. Today, we have many more options available to us than just opening a window. However, our needs and concerns have become significantly more complex in the modern world. HVAC technology is advancing quickly to address these needs. Energy recovery ventilators (ERV), one of the latest technological advancements, are both energy-efficient and powerful. Their qualities make ERV an ideal choice for larger facilities and commercial buildings, allowing building owners to keep occupants comfortable while keeping utility costs low.
An ERV system works on the zeroth law of thermodynamics, which states that if two thermodynamic systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. So, in terms of HVAC, if hot air is being exhausted from an HVAC system in the winter, you could use the energy it contains to preheat the outside air as long as the two were passing near each other. It also works in reverse: if cool air from the inside of the building passes hot outside air coming through the system, it will help cool it down.
In addition to heat transfer, humidity is also transferred between the two airstreams. This can be extremely valuable to ensure that humid summer air does not lead to condensation when it is cooled and so on. Systems that do not include humidity transfer are called heat recovery ventilator (HRV) systems.
Anytime you can reuse any energy downstream in a process, it tends to save property owners and building managers on utility bills. For some HVAC engineers, however, the scale of the savings may not be immediately apparent. Indoor air quality and incoming fresh air are required elements given building codes and the standards set by the American Society of Heating Refrigerating and Air-Conditioning Engineers (ASHRAE).
By using the outgoing temperature to help temper incoming fresh air, ventilation HVAC costs can be reduced by up to 40% over conventional ventilation options. These savings can continue for 20 to 25 years, or the expected lifetime of the units. This also leads to a quicker payback period, a key consideration for engineers working within capital project constraints.
ERVs also provide substantial benefits when compared to conventional options for ventilation units within commercial HVAC systems. ERVs require smaller-diameter ductwork than other ventilation measures, ensuring they fit in smaller building envelopes.
Further, because they reduce the load on the overall HVAC system when it comes to heating and cooling spaces, ERVs lengthen the lifespan of older furnaces, boilers, and air conditioning systems. Just as they reduce costs by about 40%, they also reduce the overall HVAC load by a similar percentage.
Maintaining comfortable temperature and humidity levels in buildings is currently the largest single utility driver. About 70% of electricity goes to this purpose. That certainly is not sustainable over the longer term.
The U.S. Green Building Council’s LEED (Leadership in Energy and Environmental Design) certification programs are considered some of the most stringent requirements for maximum energy efficiency and occupant health protection via interior air quality measures. They mandate very efficient energy recovery ventilation systems as part of any commercial HVAC system.
So, too, has ASHRAE in its Standard 189.1. It focuses on not just energy efficiency, but also indoor environmental quality, one of the key metrics where ERVs can make a substantial difference. The standard requires ERVs to have a recovery effectiveness of at least 60%.
These increased efficiency requirements are only going to trickle down into the commercial HVAC specifications, regardless of whether a building owner is seeking LEED certification because of a project. Keeping abreast of ERV developments will help in designing ever more advanced systems.
Many HVAC engineers are aware of the growing popularity of energy recovery ventilator systems but are not always sure if they can make them work within the budget of an architect’s plans melded with a commercial construction company’s capabilities.At Windy City Representatives, we represent the leading commercial HVAC manufacturers, including the top names in energy recovery ventilator systems. Contact us today to for a quote or bid.
As far back as the Middle Ages, people have associated air quality and health for centuries—with good reason. However, with the advent of heating, ventilation, and air conditioning systems, indoor air quality is both increasingly controllable and important. As the difference between indoor and outdoor temperatures increases, so does the proliferation of potentially deadly health hazards indoors. If your environment is too humid, there’s an increased potential for the growth of biologicals such as black mold. If it is too dry, you can risk nosebleeds, respiratory infections, and dehydration.
So, how can you reach the right humidity level?
Maintaining relative humidity (the amount of moisture in air compared to how much it can hold) is so crucial to human health that the Centers for Medicare and Medicaid Services require hospitals to maintain minimum levels of 20%. Other standards agencies are more precise, setting a maximum humidity level of 60% to inhibit bacterial and mold growth.
As with health, humidity control is also crucial in manufacturing environments. Too low, and static electricity can cause arcs or short-circuit electronics. Too high, and the likelihood of condensation can ruin products and slow down production.
This represents both a challenge and an opportunity for HVAC engineers. By leveraging interior humidifiers in cold weather and outdoor ventilation in hot weather, they can provide a consistent, healthy, and cost-effective environment.
There are many options for commercial humidifiers. Choosing among them is a daunting task for any engineer. Luckily, it’s not quite as complex as it seems. They fall into two groups: humidifiers which provide additional moisture by creating steam (an “isothermal” process), or by spraying droplets of water into a building’s air (an “adiabatic” process). Isothermal humidifiers are either steam-, gas-, or electric-powered, while adiabatic humidifiers are solely electric.
Isothermal humidifiers are effective but also create heat, which can be a problem during the spring and summer. Adiabatic humidifiers, on the other hand, are slightly less powerful, making them most useful in smaller areas or rooms with specific humidity requirements.
There are always variables that come with designing an all-new HVAC system for a facility or retrofitting existing ones to include humidifiers for commercial buildings. Since humidifiers are often a secondary concern after designers address heating, cooling, and ventilation, they must work within a few parameters. Their specifications include:
These are just a few of the considerations designers must address when they incorporate humidifiers into their commercial buildings. Luckily, you’re not short on options, and Windy City Representatives are here to help you find the right one for your needs.
Windy City Representatives is a leading distributor for name-brand, reliable, and high-quality humidifiers. Contact us today for a quote or bid on your commercial project.
Makeup air units are crucial in today’s commercial spaces; they’ve even trickled into the residential market in the form of air purifiers and similar systems. Although they are critical to maintaining proper oxygen levels and removing contaminants from outside air, they can be misunderstood in terms of their usage and placement within an overall HVAC system.
Essentially, HVAC exhaust fans remove air from buildings and makeup air units pull in fresh, oxygenated air to replace it. Without makeup air units, HVAC systems would have to draw fresh air through gaps in the building itself, which is both less effective and less efficient. Makeup units also incorporate filters, which purify air.
However, building a makeup unit to specification can be a complex process. They must be able to work with the outside ambient temperature in order to heat or cool the air to a comfortable temperature and humidity level.
Each room has different expected ventilation needs based on exposure to chemicals and irritants in the air and the amount of physical activity performed in that location. For example, the California Building Code notes that dining rooms and conference rooms must have a ratio of 0.5 cubic feet per minute of airflow for every square foot of the room. In more active spaces, like casinos or dance floors, those requirements jump up to 0.68 and 1.07, respectively.
Makeup air units are vital throughout these spaces simply because the only alternative for ventilation is windows that are open to the exterior. While this explains the common practice of grouping rooms in insular hubs in certain retail environments or in schools, it simply is not feasible in a scenario like a mall or an office complex. There, to meet local, state, or national requirements, as well as the standards set by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, makeup air units must be incorporated to meet airflow ratios.
Educational settings are an interesting situation for HVAC engineers because they do not have very stringent requirements in terms of minimum outside air, and no requirements in terms of how much air must be brought in from outside. Instead, ASHRAE specifies 15 cubic feet of air per minute per person per room. For example, a classroom with 20 students would require 300 cubic feet of air per minute.
Makeup air units are also invaluable in enclosed spaces with potentially dangerous fumes like science labs or auto shop classrooms. They also regulate both humidity and condensation, preventing potential damage to the rest of the HVAC system.
Hospitals are among the most complex facilities in terms of ventilation requirements for different types of rooms. For instance, a ground-floor lobby would have different ventilation needs than an office, an exam room, or even a cafeteria. The most stringent requirements regarding makeup air units come from the Centers for Medicare & Medicaid Sciences’ guidelines for operating rooms.
There, they state that humidity levels be at least 20 percent, with 20 air changes per hour, four of which must be completely outside air. Best practices from ASHRAE and the Association of Operating Room Nurses offer a max limit of 60 percent relative humidity and more outside air.
In addition, most burn units, operating rooms, and isolation units must keep positive pressure relative to adjacent rooms. This helps contaminants from entering those rooms and improves outcomes for patients. Makeup air units can help pull air out of the rooms as necessary and replace it with filtered, uncontaminated air.
For each of these cases, specifying the right makeup air units is crucial, as is designing a system that adequately accounts for the amount of outdoor air necessary to meet these stringent regulations.
If you’re designing an HVAC system, you probably have a few considerations in mind—your heating and cooling system should be reasonably priced, easy to maintain, and reliable. Makeup air units are an ideal choice, and Windy City Representatives can help you choose the right unit from a trusted manufacturer for you.
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