Heating, Ventilation and Air Conditioning (HVAC) systems are those mechanical systems that are involved with facilitating comfortable air temperatures for people in residential and commercial buildings, as well on various types of vehicular transport.
HVAC is a scientific discipline that focuses on such specialties as thermodynamics, fluid mechanics, heat transfer and refrigeration. The process is not as simple as creating air that is more comfortable than outside; but it is also involved with the removal of odours, moisture, heat, bacteria and dust from the air. It keeps the momentum of the air and prevents it from becoming stagnant.
The first component of any HVAC system is heating, which can be delivered in a variety of forms, most notably small, portable heaters, and centralised heating systems designed to warm up an entire room or building. The distribution of the heat is usually done via pipes or air.
Ventilation in an HVAC system relates to the process of replacing air in a room in order to control temperature or remove unwanted details in the air such as moisture and bacteria. Ventilation can occur as simply as natural means (such as opening a window), or by mechanical means such as an air handler like an exhaust fan in a kitchen or bathroom.
Air Conditioning is a system that is used to control cooling and humidity. It is designed to work with no natural ventilation present, as this would disrupt the constant inside air situation. The refrigerant starts as a gas, before it passes through a series of compressors and coils and i expelled via a valve at a consistent and constant flow. Air conditioning can also include a reversing valve to have both a cooling and a heating function. This is extremely popular in countries with highly variable climates.
Air conditioning is available in a variety of forms, with the two most common being ducted air conditioning and and split system air conditioning. Contemporary air conditioners all have air filters which need to be cleaned regularly. The systems themselves also need to undergo scheduled maintenance and service checks so they remain running in peak condition.
Manufacturers of HVAC systems are always aiming to make their technology more energy efficient and safer on the environment. For example, in air conditioning the R22 gas that has been the staple of the industry for decades is being phased out for more environmentally friendly alternatives by 2021.