Because of the world’s varying seasonal and weather conditions, it has been a nature for some homes and spaces to install ventilation systems. These systems have been really important to people who wants to relax and live comfortably and at the same time work without disturbing to the extreme heat or cold brought by weather changes. As for tropical and very hot countries who experienced long summer seasons, air conditioning systems have been a need and prominently seen among these regions. It is an exact opposite for temperate and polar regions who experienced long winter seasons who frequently places heating systems through their buildings and homes to survive the utmost cold and long winter nights. In the combination of these, seasonal countries who experienced both summer and winter uses heating and cooling systems to maintain the normal room temperature during winter and summer.
Not just within our personal spaces but it has indeed expanded its use not just through personal spaces but to malls, hotels, schools, hospitals and even to automobiles and vehicles like cars, trains,airplanes, and ships. The ventilation system has provided a wider stretch towards helping people all over the earth.It has been an alternative escape route towards nature’s effects on climate change and global warming.
What is an HVAC system?
-Heating, ventilation,airconditioning, and cooling systems (HVAC) is a technology-driven system providing environmental comfort to indoor spaces and automobiles by controlling room or space temperature and humidity conditions. It also controls the movement and distribution of air on the corresponding space.
Importance of HVAC systems
-HVAC systems have been widely used by a lot of people. It is important for the following reasons;
1.provides thermal and environmental comfort towards space.Therefore, a highly conducive working or personal space is experienced;
2.protects and enhances air quality;
3.filters and sweeps dust and small particles;
4. improves health condition and prevents from getting diseases and illnesses brought by extreme or changing weather conditions;
5.maintains temperature and air distribution within the space;
How does HVAC system works?
An HVAC system works differently as compared to other technologies seen today. It is governed by a combination of sciences based on thermodynamics,heat, and fluid flow. That is why it is really important to know how it works before purchasing one of these. Not just it’s sciences involved but it’s parts and how each part correlates upon the other part.
The basic system consists of eight parts.The furnace, heat exchanger, evaporator coil, condensing unit, refrigerant lines, thermostat, ducts, and vents. Now, let’s get to know each part as described below;
– typically fairly large and often installed in the basement, attic, or a closet. It is filled with hot water, air, or steam and pushes cold or hot air outward into the ducts that run through every room in the building. Throughout the ducts, vents allow warm or cool air to pass into rooms
Ducting- Supply Air Ducting (Coil Case, Plenum, Straight Duct)
Connections-Supply Air Runs
Types of Furnaces:
a.Single Stage Furnaces
-have only two modes: on or off.
The thermostat controls the furnace, turning it off or on as needed. Blowers within the furnace regulate the amount of air forced through the ducts and vents.
b.Two Stage Furnaces
-starts up when the thermostat indicates a need for cool air or hot air. For about 10 to 15 minutes, the furnace operates at only two-thirds of its potential to save energy. If the temperature of the room returns to the optimum level, the furnace then turns off. If not, the furnace kicks into full power. Blowers with variable speeds allow users even more flexibility in controlling the output of the unit.
– reside in the housing of every furnace unit. When the thermostat activates the furnace, the heat exchanger begins to function as well. Air is sucked into it, either from outside or a separate duct that pulls cool air out of the building’s rooms. This type of duct is called a cold air return chase. When the cool air comes into the heat exchanger, it is quickly heated and blown out through the ducts to be dispersed in the building. If the furnace operates on gas, the heating is accomplished by gas burners. If it uses electricity, it is done via electric coils.
-Like heat exchangers, evaporator coils are also part of the furnace unit but serve the opposite function and are attached to a different part of the furnace. Instead of being within the furnace housing, they are installed inside a metal enclosure affixed to the side or the top of the furnace.
Evaporator coils are activated when cool air is needed. When triggered, they supply chilled air, which is the furnace blower picks up and forces along the ducts and out through vents. The internal design of an evaporator coil resembles that of a car’s radiators. Evaporator coils are connected to the HVAC system’s condensing unit, which is typically located on the exterior of the building.
-The condensing unit is installed outside the building, separate from the furnace. Inside it, a special kind of refrigerant gas is cooled through the exchange of heat with the air outside. Then, it is compressed and condensed into liquid form and sent through a tube or line made of metal. This parts runs straight to the evaporator coil. When the liquid reaches the coil, a series of small nozzles spray the liquid, lowering its pressure and allowing it to expand back into gaseous form. During the evaporation, heat is absorbed, causing a sudden drop in temperature and supplying cold air for the furnace blowers. The refrigerant gas is then sent back outside to the condensing unit, and the process is repeated again to generate additional cold air.
The refrigerant lines are the metal tubes that carry the liquid to the evaporating coil and return the gas to the condensing unit. Commonly made from aluminum or copper, they are designed to be durable and functional under extreme heat and cold.
The thermostat controls the function of the furnace. Directly connected to the furnace through wires, it has temperature-sensing technology as well as user controls. Moreover, it is usually positioned on a wall where it can easily discern temperature and remain accessible. A large building may have more than one thermostat to control different areas. The people inside can manually set the thermostat to a certain temperature. If the air in the room or building is too cold, the heat exchanger kicks in and blows heat through the vents like a fan. If the room is too warm, the condensing unit and evaporator coil start to function, and the air conditioning system sends cool air throughout the building or to one particular section of the building.
Heating ducts are installed during the construction of a home or a building. They are often run through the ceiling. In each room, at least one rectangular opening is cut into the duct so that a vent or vents can be installed. Sometimes, dampers are installed to regulate air flow. The air handler, or AHU, often attaches to the duct system as well and regulates air circulation as part of the ventilation system
It is typical to have vents placed in the ceiling, with their edges corresponding to the opening in the duct above. As warm or cool air pours through the ducts, vents allow it to disperse into the rooms below. Vents are usually made of metal, which can handle a wide range of temperatures. The vent is comprised of a rectangular edge or frame, within which is a series of thin, metal slats angled to channel the air downward. Some also include a manual control that lets users change the angle.
Tips on Buying HVAC systems
- The Air-Conditioning Option. As a rule of thumb, if local temperatures rarely rise above 85 degrees Fahrenheit, you probably don’t need central air-conditioning. On the other hand, central air is often regarded by realtors as a valuable selling point, so if there’s a chance you’ll be transferred to another region or are likely to put your home on the market for any reason in the near future, central air-conditioning may be a good investment. Top-of-the-market houses get top-of-the-market prices because they have all the bells and whistles. For people with asthma and other allergy problems, central air with its ability to filter and “condition” household air can also have health benefits.
- Beware of Oversize Systems. Strange though it may sound, too much heating capacity will make a system less efficient. It will cause the system to cycle on and off frequently, producing excess wear and tear on the components. The system may never reach peak operating temperatures.
To be sure your system is suited to your home, ask your HVAC contractor, heating engineer, or whoever designed the system to walk you through the calculation. The process consists of determining what the heating load is (based on an arithmetical formula that factors in the size of your home, its insulation, and the local climate). The system capacity should be no more than 25 percent greater than the calculated heating load.
- Simple Is Usually Less Expensive. Staying with your existing system is almost certainly the cheapest route. If your system has enough capacity that it can be extended to heat (or cool) new spaces, that approach will probably be less expensive than installing an all-new system.
- Buy Quality. Good shoppers don’t always buy bargains. Buying durable boilers or furnaces that come with long warranties often costs more initially but, over the years, presents fewer headaches. Good furnaces often are guaranteed for twenty years, boilers for thirty, heat pumps for less.
- Think Locally. Don’t buy equipment that no one in your area can service. If the only HVAC contractor who’ll bid your job is a long-distance call away, you could be asking for trouble. These sophisticated modern systems require occasional checkups by service people familiar with their design, installation, and individual characteristics. One industry study found that half of all service calls were the result of improper or insufficient maintenance.