What is the purpose of a fan in HVAC system?
Heating, Ventilation, and Air Conditioning (HVAC) systems are equipped with fans, which serve as cooling and air circulating devices. Fans are of great significance in HVAC systems. However, not each cooling or ventilation activity is performed by one type of fan.
What is axial fan in HVAC system?
In an HVAC system, the axial fans are used for cooling or diluted ventilation purposes. These can be AC/DC powered. There are two types of these fans used selectively in the HVAC systems. Tube Axial Fans : In these fans, the fan blades are enclosed in a tube from the outer tips.
What is an HVAC blower fan?
Your heating, ventilation, and air conditioning systems come equipped with a fan that you can control with your thermostat. HVAC blower fans are used to circulate air in a room and remove hot and cold spots until the temperature set on your thermostat is achieved.
Is each cooling or ventilation activity performed by one type of fan?
However, not each cooling or ventilation activity is performed by one type of fan. HVAC systems are often designed for result-centric output and therefore for different activities, and performance parameters, different types of fans are used in an HVAC system. There are ideally two types of industrial fans, namely, axial fans and centrifugal fans.
Where is the fan in an HVAC system?
The blower fan is located inside a horizontal air conditioning unit in many home air conditioning systems, especially when the air handler is located in an attic or crawl area.
When should you run HVAC fan?
Here's when to use your HVAC fan setting:Run the Fan When You're Not Home. You don't want to waste energy when you're out of the house. ... Filter the Air During Allergy Season. Any time you notice a runny nose, a dry throat or a persistent cough, it could point to your allergies. ... Share the Love.
Should HVAC fan be on AUTO or on?
Since the AUTO setting means the fan is only engaged when the system is on, rather than constantly blowing, AUTO is the most energy-efficient option between the two settings. This means you'll be using less energy and saving money on your electric bill by using the AUTO setting.
Should HVAC fan run continuously?
Better Indoor Air Quality Whenever the fan is on, air is going through the furnace filter. Leave it on continuously and you're likely to see less dust around. It's also important to have a good filter. The many types of HVAC filters can help reduce allergies, VOCs, as well as bacteria and viruses.
Does HVAC fan use a lot of electricity?
The fan itself runs about as much energy as a refrigerator would. This can still add up to $50 a month, or $600 a year. This cost can be even higher if you consider the AC unit working harder to counteract the effects the fan may have.
Should HVAC fan be on in winter?
The most obvious benefit to keeping the furnace fan on the “on” setting is more even heating and cooling distribution. Heat has a tendency to rise in the home during the winter due to “stack effect,” and parts of the home that see greater sun exposure may also become warmer than the rest of the house.
Is it OK to leave the AC fan on?
Leaving the fan on eases the strain on the HVAC system. Constant motion means fewer stops and starts, which can extend the lifespan of your unit. Constant fan use keeps the air in your home circulating through your air filters and UV sterilizers if you have them.
How long should my HVAC fan run per hour?
Most systems should run about 2-3 cycles per hour. How long should the furnace or AC run in a given cycle? Typically 10-15 minutes in mild weather. The closer you get to the max design temperature in heating (0 Degrees) or cooling (90 Degrees) the longer the run cycle will be.
Should HVAC fan be on in winter?
The most obvious benefit to keeping the furnace fan on the “on” setting is more even heating and cooling distribution. Heat has a tendency to rise in the home during the winter due to “stack effect,” and parts of the home that see greater sun exposure may also become warmer than the rest of the house.
Does running HVAC fan reduce humidity?
During the colder season, you can run the furnace fan to help reduce humidity. The furnace fan helps by pushing the air through the air conditioner's evaporator.
Can I run my HVAC fan 24 7?
Less frequent starts and stops of the fan can reduce the stress from startup, and potentially help extend its lifespan. Leaving the fan on 24/7 ensures cleaner air, as the air is pulled through the filtration or UV light system. This can be better for people with allergies.
What are the two types of HVAC fans?
There are ideally two types of industrial fans, namely, axial fans and centrifugal fans.
What is centrifugal fan?
Centrifugal Fans: The centrifugal fans consists of blades aligned 90° to the axis of the rotor. The construction of these fans resembles the hamster wheel. These fans are suitable for generating high-volume air for cooling and ventilation applications. These fans use centrifuge action to increase the volume of air and deliver high pressure, high volume air output.
What are the different types of fans?
Different Types of Fans and Their Roles in HVAC Systems 1 Forward Curved: The forward-curved design offers high-pressure air output. The tips of blades in these fans are forward-curved and therefore provide moderate air volume at high pressure. 2 Backward Curved: The backward fans feature straightened or slightly backward curved blades. These fans consume low power and generate less noise. These fans are used when a high volume of air is needed at comparatively low power. The most common application of these fans in HAVC systems is energy-recovery ventilation (ERV). 3 Airfoil: The airfoil type of centrifugal fans feature inclined blades that create an airfoil construction. The inclination of these blades is set according to Bernoulli’s Principle. These fans can generate high-speed air output without creating a swirl. These fans operate silently and are suitable for HVAC systems with active ventilation requirements.
What is forward curved fan?
Forward Curved: The forward-curved design offers high-pressure air output. The tips of blades in these fans are forward-curved and therefore provide moderate air volume at high pressure.
What is an axial fan?
Axial Fans: In this type of fan, the blades are attached parallel to the direction of the rotor axis. In an HVAC system, the axial fans are used for cooling or diluted ventilation purposes. These can be AC/DC powered.
What are the different types of HVAC fans?
The Different Types of Fans Used in the HVAC Industry. A fan is a key component of any HVAC system. The most common HVAC fans are axial, forward-curved centrifugal, and backward-inclined, and each is uniquely suited to certain purposes. It’s important to understand each fan’s differences in energy efficiency, cost-effectiveness, ...
What is centrifugal fan?
Centrifugal Fans, which are categorized by their radial, forward curved, or backward inclined blade shapes, increase the speed of an air stream with a rotating impeller . The speed increases as the air reaches the ends of the blades and is then converted to pressure. These fans are able to produce high pressures, ...
What is a forward curved fan?
Forward-Curved Centrifugal Fans, look more like hamster wheels and can create more air pressure. Because of this, they tend to be noisier than axial fans and require more power to run. They are durable, easy to clean and maintain, and have less problems with resistance. Forward-curved centrifugal fans are also called blowers.
How do axial fans work?
These fans work like an airplane propeller—blades generate an aerodynamic lift that then pressurizes the air. Propeller fans embody only a motor and a propeller used to drive the airflow. Similar to a propeller fan, a tube axial fan includes a venturi that surrounds the fan propeller and is designed to reduce the air leak.
Why use an axial fan?
Using an axial fan for that purpose would make the system perform poorly and likely lead to extra maintenance and repairs. Even though it would be less expensive initially, it would cost you more in the long run and would not function the way you would expect from such a system.
Is an axial fan noisy?
Axial fans are inexpensive, compact, and light, making them a favorite for industrial applications. They are, however, usually noisier than centrifugal fans. Noise can be abated by insulating the duct; mounting the fan on soft materials like rubber or using a spring isolator to reduce the amount of transmitted vibration;
Why do we need fans?
In simple terms, fans are used to establish airflow whenever it is required and does not occur naturally. For this reason, fans are fundamental in HVAC systems. However, the physical construction of fans varies, and each type is intended for different applications.
What is a centrifugal fan?
Centrifugal Fan. These fans are characterized by having an appearance similar to that of waterwheels or hamster wheels. Assuming the same airflow, a centrifugal fan will establish a higher pressure than an axial fan, consuming additional power.
What is an axial fan?
Axial fans have the simplest construction, with their blades arranged in a propeller shape around a rotating shaft. These fans are designed for applications where both the airflow and static pressure are relatively low.
What is a backward inclined fan?
Backward inclined fans can be further classified into curved-blade and straight-blade fans, and can be driven just like a centrifugal fan.
What is a VFD fan?
Variable frequency drives (VFD) condition the voltage and frequency supplied to the fan to achieve speed modulation, allowing a seamless transition between different rpm values. For fractional horsepower fans, brushless DC motors can achieve the same result as VFDs in larger motors.
Do centrifugal fans make noise?
Consider that centrifugal fans produce more noise than axial fans, so their use is only recommended if the application demands it . They can be driven directly or through a belt, and can also be enhanced with a variable frequency drive.
Can a VFD control airflow?
In these cases speed control is directly related to airflow (cubic feet per minute), since there is no resistance to airflow. The same cannot be said of ducted installations, where it is necessary to account for static pressure variations - precise airflow control can only be accomplished with a VFD.
What are the different types of HVAC fans?
There are three basic fan types that are usually encountered in the HVAC industry. The Axial Fan, the Forward Curved Centrifugal Fan and lastly, the Backward Inclined Fan.
What is centrifugal fan?
Centrifugal fans look similar to hamster exercise wheels. These types of fans produce more pressure for a given air volume than axial fans. They are usually noisier as compared to axial fans and are suited for applications with higher air flow volumes and pressures. It has 3 types of drive mechanism: direct, belt, or variable drive.
Where is the axial fan located?
Axial HVAC fans can usually be found positioned on top of an HVAC Rooftop or home compressor that is outside a house. A basic HVAC system which doesn’t run a heat pump is designed with condenser coils which remove heat from an area. These coils have fins that need air to move through them so as to remove heat. Since these sections don’t require a high power fan, an axial fan is the best and most cost efficient solution.
What is a backward inclined fan?
The backward inclined fans are designed to handle large volumes of clean air as needed in heating, ventilating, and air conditioning systems. These are also used in many industrial air supply and exhaust applications.
What is an axial fan?
Axial fans, also known as propeller fans, are engineered to move a low volume of air under low static conditions (static pressure is the resistance to air flow). These types of fans are low cost, and don’t work well when it faces resistance. Since propeller fans are low cost, most are built to run on Single Phase Voltages. These types of fans are more suited for applications with lower air volumes and pressures.
Do HVAC units have backwards inclined fans?
There are some HVAC Rooftop units and HVAC accessories that may contain one or a series of backward inclined fans .
How Do Exhaust Fans Work?
Exhaust fans pull odors, fumes, and moisture from an area of the home, venting them outdoors for removal. The fan uses a motor to turn its blades, which function to pull air out of the space. The stale, humid, or contaminated air is propelled through the exhaust vent, exiting the home.
What happens when you use an exhaust fan?
Exhaust fans remove excess moisture that can damage the home. Condensation from hot water use can build up on walls, ceilings, and other surfaces, leading to mold growth.
Why do we need exhaust fans?
Exhaust fans are used to pull excess moisture and unwanted odors out of a particular room or area. They are commonly found in bathrooms and kitchens, where moisture can build up due to activities such as showering, washing, or cooking. They provide ventilation to areas, reducing chemical fume buildup and removing other contaminants that can be harmful when breathed in.
Why is my exhaust fan so loud?
Poor installation can cause the exhaust fan to be noisy when operating. This operating noise sometimes keeps occupants from using the exhaust fan when they should be – such as when taking a long, hot shower, cleaning using chemicals, or cooking a meal on the oven or stove. Not using exhaust fans will cause moisture issues in the home, lingering odors, and poor indoor air quality.
What happens if you don't install an exhaust fan?
If the exhaust fan is not installed properly, heat and moisture may be escaping into other areas of the home. If the unit is not insulated correctly, the air pulled from interiors can be lost within the home’s attic, which can lead to moisture issues.
Is an exhaust fan good for indoor air quality?
Using an exhaust fan is very beneficial for the home, indoor air quality, and comfort of occupants.
Can exhaust fans be vented to the outside?
There are many different models of exhaust fans available for use in homes. Exhaust fans are either vented directly to the outdoors via the unit itself or dedicated duct work, or is connected to your home’s ventilation system. Wall- and ceiling-mounted exhaust fans commonly used in bathrooms as well as range hood exhaust fans in kitchens are typically vented directly to the outdoors. Inline exhaust fans are models that connect to the home’s duct work, expelling air through the home’s existing ventilation system.
What is fan mode on AC?
Fan mode on AC is simply a setting on your air conditioner that keeps the blower fan running regardless of whether the cool air is on or not. There are pros and cons for leaving it on. One application for running the fan on the air conditioner continuously is the ability to keep the temperature even throughout the house even when the cooling is off.
Why does my AC fan keep going on?
Two, keeping the fan on continuously when the AC is not running evaporates the moisture that is normally condensed, and sends it back through the system. The result is higher humidity inside of the house, which means that the AC has to work extra hard when it kicks on to counteract the effect of the humidity.
Why does the fan keep running on my air conditioner?
The easiest things to check when your AC fan won’t stop running is whether or not the mode is set on Auto or On. If it is on on, there you have it. Super easy fix.
Why does my air conditioner have to be outside?
That is one of the primary reasons that air conditioning is known to be a source of indoor air pollution. Because the same air is being distributed through the system and throughout the house.
Why does my AC fan keep running when it is not running?
Leaving the fan running when the AC is not running is a sure way to increase the moisture in the air because any moisture in the system will evaporate and distribute back through your house. Humidity is actually reduced more when the AC is running on cool. And if your AC has a dry mode, it will leave in reduce humidity further.
What happens if HVAC filters get dirty?
If they get to dirty, then the air can’t flow through the system properly and the system will continue to run trying to reach the desired temperature set on the thermostat.
Why is it better to run AC on auto or electric?
Being that the AC he is one of the biggest energy hogs in the home, running the AC on auto, is usually the best choice because it keeps the utility bill down.
Axial Fans
Centrifugal Fans
- Centrifugal Fans, which are categorized by their radial, forward curved, or backward inclined blade shapes, increase the speed of an air stream with a rotating impeller. The speed increases as the air reaches the ends of the blades and is then converted to pressure. These fans are able to produce high pressures, which makes them suitable for harsh ...
Applications of Fan Types
- Though axial fans are usually the least expensive, they’re not the right solution for every situation. Because of their features and capabilities, they are best for compact electronics, automotive products, medical devices, and appliances as well as large applications such as cooling towers, vending machines, outdoor air conditioner compressors, and combustion engine cooling. Axial f…
Find The Perfect Fan For Your HVAC System Needs
- Even among HVAC fan types, there are a variety of shapes and sizes that will help you narrow down the best option for your project. Take a look at our selection of fans listed in Pelonis Technologies' catalogue and see which one is right for you. If you’re still unsure on which fan is right for you, make sure to download our eBook, How to Select a Cooling Fan. Additionally, we c…