HVAC Systems

September 2nd, 2009 BY Angelina Leigh | No Comments

Highly technical and education information is almost always boring and surely just about only 60% comprehensible. It’s like a prerequisite of some sort in order for it to be deemed intellectual in quality, yet it’s all undeniably precious useful knowledge.
 
Let’s just take for example the HVAC system. Sounds complicated and therefore intriguingly intellectual right? Well quite so because HVAC stands for Heating, Ventilation and Air-Conditioning and they are one of the most complicated technologies of our time. The HVAC system exists to help maintain good indoor air quality through the provision of adequate ventilation with filtration and provide thermal comfort. That means it’s a widely used technology (worldwide reach) with severe direct impact potentials on the users health as well as that of the environment. HVAC systems are among the largest energy and water consumers with a loud acoustic effect.

Follow so far? No? Well maybe this will make it easier. Your air-conditioning unit is part of the HVAC system.

Now ask yourself what exactly does your air-conditioning unit function to do? A simple answer would be, it blows out cool air to keep the room space temperature comfortable. But how exactly does it to that? I won’t go into detail with it because it’s technical and boring so just appreciate that an air conditioning unit have 5 cycles or loops. They are the

  • airside loop,
  • chilled-water loop,
  • refrigeration-equipment loop,
  • heat-rejection loop, and
  • controls loop

In the briefest form we’d say it takes the warm/hot air, cools it and blows it back out as cool dry air. Now in order for the cooling process to function you need a refrigerant which is a fluid capable of changes of phase at low temperatures (just understand that it is a cooling substance).
Now these chemicals are many in kinds but has always caused environmental alarm which the most famous likely being chlorofluorocarbon (CFC). CFC is infamous for its unforgiving ozone depleting effects. But since 1987, the countries around the world (Sweden being the first) had started to ban/faceout CFC products and today we are almost free of it.

So what new refrigerant runs within our air-conditioning units? Well that would be hydrofluorocarbons (HFCs), the alternative to CFC. Hydrofluorocarbons (HFCs) does not contribute to ozone depletion but it brings about another issue of its own – global warming (the heat generated from your air-conditioning unit has to go somewhere so it’s released back out to the environment).

Alternatively there are natural sources of refrigerants such as butane or ammonia but they come with their own price – they are expensive, flammable and toxic (ammonia anyway).

Therefore the bottom line is, there is no perfect refrigerant – if there is, we have yet to discover it. All we can do in the meantime is be efficient in the use of the HVAC system.