Heating, ventilation and air conditioning can be defined as the technology of indoor and vehicular environmental comfort. The main purpose of HVAC is to provide “thermal comfort”, which can be defined as the condition of mind that experiences contentment with the thermal environment. The human body can be viewed as a heat engine where food is the input energy. HVAC is an essential part of residential structures such as single family homes, apartments, hotels and residential facilities, industrial and office buildings such as skyscrapers and hospitals, on ships and submarines, and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoor sources. In an HVAC system, The three functions of heating, ventilation, and air conditioning are related to each other, especially with the need to provide thermal comfort and acceptable indoor air quality within reasonable installation, operation, and maintenance costs. HVAC systems can be used in both domestic and commercial environments. HVAC systems can provide ventilation, and maintain pressure relationships between spaces.
Nowadays, in modern residential structures, the design, installation, and control systems of these functions are integrated into one or more HVAC systems. When it comes to very small buildings, contractors normally estimate the capacity and type of system needed and then design the system, selecting the appropriate refrigerant and various components needed. For larger buildings, building service designers, mechanical engineers, or building services engineers analyze, design, and specify the HVAC systems. Specialty mechanical contractors then fabricate and commission the systems. Building permits and code-compliance inspections of the installations are normally required for all sizes of building.
An HVAC system is executed in individual buildings or other enclosed spaces. The equipment involved is in some cases an extension of a larger district heating (DH) or district cooling (DC) network or a combined DHC network. In such cases, the operating and maintenance aspects are simplified and metering becomes an essential part of the bill for the energy that is consumed, and in some cases energy that is returned to the larger system. For example, at a given time one particular building may be utilizing chilled water for air conditioning and the warm water it returns may be used in another building for heating, or for the overall heating-portion of the DHC network.Basing HVAC on a larger network helps provide an economy of scale that is often not possible for individual buildings, for utilizing renewable energy sources such as solar heat, winter’scold, the cooling potential in some places of lakes or seawater for free cooling.
An HVAC system is generally based on inventions and discoveries made by people like Nikolay Lvov, Michael Faraday, Willis Carrier, Edwin Ruud, Reuben Trane, James Joule, William Rankine, Sadi Carnot, and many others..The invention of the components of Midlothian HVAC systems went hand-in-hand with the industrial revolution, and new methods of modernization, higher efficiency, and system control are constantly being introduced by companies and inventors all around the world.