What You Need to Know About Home Heating and Ventilation
At Delaware Heating and Cooling, our technicians have been educated and trained at higher learning or vocational institutions for the purpose of becoming certified and licensed by state regulators. When talking shop, we sometimes reminisce about how our technical formation was the first time we were formally introduced to the world of heating, ventilation, and air conditioning (HVAC) systems. While some of the physics principles that are present in HVAC were discussed in high school, for the most part we tend to agree that the American school system does not provide enough information that could be useful to future homeowners.
If you think that HVAC for the most part consist of generating and circulating hot or cool air in order to rise or lower indoor temperatures, you are somewhat right, and this happens to be the extent of knowledge among average homeowners. The reality of HVAC, however, is that it is more complex than this, and there are certain aspects of HVAC systems you should learn about as a homeowner. Once you become familiar with how heating and cooling mechanism work, it will be easier for you to think about proper maintenance and its importance with regard to keeping your HVAC systems efficient during the warmest and hottest days of the year; moreover, it can also help you notice certain problems that can develop into costly repairs if not handled in a timely manner.
Without further ado, let’s get into some of the basics of HVAC you may not have learned in school.
The Need for Residential HVAC
If you live in the Delaware region, chances are that your home has HVAC systems to provide comfort when seasons change and temperatures get either too hot or too cold. This is not the case in other parts of the world because the need for electro-mechanical HVAC systems is largely dictated by the regional climate. In some Caribbean islands, for example, homes have natural air circulation systems that take advantage of wind conditions and can handle the hottest months of the year. This is also the case in certain mountain regions of Costa Rica, where temperatures are generally mild most of the year. In these places, you can leave some windows open during the day to keep things pleasant. If it gets too chilly at night, you cuddle up with your loved one and throw an extra blanket on.
HVAC systems have been around since ancient times. During the height of the Persian Empire, for example, engineers used to build wind tower systems in the desert for the purpose of keeping structures in the desert reasonably cool, but the did not stop with this basic form of enhanced natural air circulation. Persian engineers also designed and built yakhchāls under wind towers. In essence, yakhchāls were large evaporation cooling structures that featured underground construction; they were used to store foodstuffs along with chunks of ice extracted from the snowy peaks of the Middle East. Yakhchāls were not exactly refrigerators, but they were efficient iceboxes, and they also served as the coolest spots in the house.
When you think that Alexander the Great put a military end to the Persian Empire about three centuries before Christ, it is amazing to learn that HVAC systems were already around more than two millennia ago. Ancient Persian engineers had a formidable grasp on certain principles of thermodynamics even though they did not publicize it on an academic level, at least not that our historians have yet learned about. To sum this brief history lesson, let’s keep in mind that the Great Salt Desert of the Iranian Plateau, which was at the center of the Persian Empire, is a hot and arid place where residents really needed to keep cool, thus signifying the geographically importance of HVAC technology.
Basics of HVAC Systems
HVAC systems consist of various components and devices that enable indoor climate control. The components include:
- The source generating hot or cool air.
- An air distribution network.
- Temperature and humidity sensors.
- A regulator such as a thermostat.
When we talk about sources, we mostly mean air conditioning compressors and heat furnaces, for example. Air is distributed by a network of ducts that can handle either hot or cold air. Sensors that check humidity and temperature conditions can send instructions to the regulator in order to keep indoor air more pleasant than it is outside. As with a motor vehicle, when HVAC components fail or are compromised, there is a strong chance of the entire system malfunctioning.
How HVAC systems work in principle is something you probably remember from school:
- Water tends to flow downward thanks to its compositions following the laws of gravity.
- Heat is a force that either moves or dissipate from warm objects to cooler objects; this is a law similar to water flowing down.
- Indoor air will be conducive to the air generated by the sources.
- A furnace will add heat to your indoor air.
- An air conditioning unit will subtract heat from your home.
The absence of heat creates cool conditions; in other words, heat is what is constantly being moved or circulated around by HVAC systems. In certain parts of Southern California, summer temperatures are so mild that you can just open windows and doors to let the breeze take care of moving the heat outside the home. If the same California home has been heating up during a sunny day, the Sun’s radiation passed the heat onto the interior air, and you can let it inside your house when it gets cooler at night so that you can sleep comfortably.
Types of HVAC Systems
Aside from natural air circulation systems, and the ancient yakhchāls mentioned above, modern HVAC systems will burn electricity or fuel in order to operate. Consider the furnace, which works by means of heating oil or natural gas. Heat pumps are electrical HVAC systems energized by the fuels that regional utility companies burn in order to produce electricity. It should be noted that the heat pump, despite its name, is also an air conditioning system that can keep indoor air cool by means of moving heat outside.
Older HVAC systems also featured boilers as part of their components, and they way they heated indoor spaces was by circulating hot water through a piping system; in other words, they moved heat through pipes. These systems also served as the hot water tank when you wanted to take a nice warm shower.
Moving Warm Air Around
In HVAC systems that generate hot or cold air at the source, the air must be forced through indoor spaces, and this is typically handled by a fan or blower. Distribution is then accomplished through the ducts. The mechanism here can be described as warm air flowing into the living spaces, which in turn feature another set of ducts transporting cold air outside. The speed of the fan blades can be regulated through the thermostat device.
The mechanism described above is known as a forced-air HVAC system, but there is also another system that works by means of gravity, and this is when the water flowing down analogy can be made to greater effect. Keeping in mind that heat always rises, we can assume that cold air will flow downwards, and this is when a gravity furnace installed at ground level will move the cold air out from the bottom and let the generated heat rise through the ducts.