An In-depth Look at HVAC Systems
A heating, ventilation and air conditioning (HVAC) system’s role is no different from that of our respiratory system. This is because the two aid in controlling the temperature, quality and movement of air required to ventilate, cool or warm an organism/room.
Fundamentally, before air is cooled or warmed, energy has to be consumed by system parts. Normally, water/air is cooled or heated after coming into direct contact with refrigerants or heat, causing it to be pushed through the pathways – tubes/ducts. It then escapes via the vents/outlets till it travels through the entire structure. This is basically a continuous process, for once water/air has travelled throughout the system, it goes back to the origin to be re-cooled/re-heated.
These are some of the attributes of a well-engineered ventilation system:
- Ability to control build-up of carbon dioxide, carbon monoxide and other miscellaneous toxic gases
- Ability to aid in circulation
- Ability to introduce fresh air
So how are you supposed to know if your HVAC system will be efficient and effective? The key things to look for include how it’s been designed, presence of passive filters, its gravity and its insulation.
Heat to an HVAC system can take the form of forced or direct air. While a direct air system takes air directly (through the use of radiators, baseboards and/or electric radiant floor systems) or hydronically (steam/hot water), forced systems have their air heated in a furnace using electricity or gas. Air is then forced throughout the building via fan(s).
All forced air systems rely on “return” cold air to the furnace, and a majority of them have two sets of outlets and ducts (one to circulate hot air and the other to return the sinking cooler air). Alternatively, these systems can have their heat generated by an exchanger cum heat pump. This exchanger is considered more efficient, for it uses condensation and compression to draw heat from air during cool weather. What makes them more exceptional is the fact that they can use ground/geothermal heat. On the negative side, once the temperatures outside become warmer or cooler than indoor air, they become less efficient.
Now that refrigeration has become so important to HVAC systems, environmental engineers alongside other climate control professionals prefer using HVAC-R, heating, ventilation, air conditioning and refrigeration, instead of the older HVAC. Traditional AC units have a condenser and compressor to cycle cooled refrigerant via an air handler/box within a building’s ventilation system. This is achieved through the use of a fan in the furnace that forces cooled air through the ductwork to its vents.
Heat pumps are in essence two-way air conditioners which are best known for making ACs a lot more efficient than they do heaters. Thus, it’s important that if there’s no ductwork (in an electric or hydronic direct heat system), a ventilation system be installed. If not, more specialized systems (mini-splits and mini-ducts ductless air conditioning) should be installed. Such systems are highly notable for running small ducts that use high pressure fans and running the refrigerant to the air handler while ensuring that each fan in each room is cooled.