HVAC Working Procedure
A building’s air conditioning is part of a larger system commonly referred to as its heating, ventilation, and air conditioning system (or HVAC for short). Your home’s Air Conditioner And Heating System is essentially an expansive machine consisting of a ventilation system, thermostat, and various devices that either heat or cool the air. Understanding the basics of how this system functions can be very helpful when deciding to repair or replace it.
V for Ventilation
The ventilation portion of your Air Conditioner And Heating System is made up of return and supply vents (also sometimes called registers), ductwork, filters, and a circulating fan. The circulating fan pulls air from inside your home through the return vents, into the ductwork, and over the devices that either heat or cool the air. Then it pushes that air back into the rooms of your home through the supply vents. This system, known as a forced-air system, is the basis for the heating and cooling of your home. Before going into detail regarding the actual heating and cooling processes, however, a very brief physics lesson is in order.
HVAC Physics
There are two key principles of physics that all HVAC systems depend on for proper functioning:
A liquid’s boiling point depends on how much pressure it is under. Many pre-packaged foods have separate, high-altitude cooking instructions for this reason because at higher altitudes the atmospheric pressure decreases, which means a lower boiling point for water. When a substance vaporizes, it absorbs heat from its surroundings to energize the change. That’s why you use heat to boil water.
Air Conditioning Systems
The air conditioning component of most residential Air Conditioner And Heating systems is a split system, so-called because the system’s work is split between an outdoor unit (the compressor and condenser) and an indoor one (an evaporator coil). Connecting the two is copper tubing which runs a refrigerant. This refrigerant is chemically designed to be capable of vaporizing at moderate temperatures, which is crucial to the functioning of the system. The refrigerant begins the cooling cycle in the compressor as a cool, low-pressure gas. The compressor compacts that into a hot, high-pressure gas, which is then piped through the condenser where it condenses into a cooler, high-pressure liquid as a fan blows the excess heat into the air outside your home. Because the refrigerant was pressurized in the compressor, its boiling point has increased, allowing it to stay in its liquid form.
Heating Systems
While there is more diversity in residential heating systems than in their A/C counterparts, the basic premise is the same. Air is drawn into the HVAC system’s ductwork, heated, and then recirculated throughout the home. The greater diversity lies in how that air is heated. Some systems, like heat pumps, are basically air conditioning systems reversed. In fact, heat pumps are able to both heat and cool, simply by reversing the hot and cold coils. When in air conditioning mode, the heat pump works as described above. When in heating mode, the hot and cold coils are reversed and the heat pump pulls in air from outdoors, essentially transporting the heat into your home. Some heat pumps even draw in heat from underground.
Need To Know About Heating & Air Conditioning Units
If you’re thinking about replacing your HVAC (Heating, Ventilation, and Air Conditioning) system, the first question to ask is this: What are the different types of Air Conditioning And Heating Systems that you can get? In the meantime, here’s a quick and easy lesson on the 4 types of AC & Heating Systems available:
The Four Types of Air Conditioner And Heating Systems
Heating and Air Conditioning Split System
A split system is an outdoor unit containing the condenser and compressor, and an indoor unit containing the evaporator coil and blower. Split-system central air conditioning is the most popular type of residential heating and air-conditioning. The furnace or heat pump is connected to the indoor unit.
Hybrid Heat Pump System
In a hybrid heating and cooling system, a heat pump (powered by electricity) is used in conjunction with a furnace that burns natural gas, propane, or fuel oil. Don’t be fooled by the name heat pump, these systems also cool your home.
Ductless Mini-Split Heat Pump
A duct-free HVAC system provides a solution for spaces where conventional ducted systems aren’t compatible. They can also be great compliments to existing ducted types of HVAC systems.
Packaged Heating & Air Conditioning System
A packaged Air Conditioner And Heating System contain the compressor, condenser, and evaporator all in one unit, often located on a roof or near the foundation. Heating and air conditioning work by producing heat or cool air through the vapor-compression refrigeration cycle. A chemical refrigerant carries heat from one part of the system to another and then releases it. There are four components in the system that work together to make it happen:
- Compressor: The compressor squeezes a refrigerant, or coolant, and turns it into a hot, high-pressure gas that is then pumped into a condenser.
- Condenser: The condenser is a long-coiled tube that is located in the external unit. The refrigerant moves through it, then the heat dissipates into the environment with the help of a fan. It turns back into a liquid as it cools, and passes into the expansion valve.
- Expansion valve: The expansion valve lowers the pressure of the refrigerant and returns it to a full liquid state before pumping it into the evaporator.
- Condenser: Like the condenser, the evaporator is a long-coiled tube. There’s less pressure in this coil, so the refrigerant turns into a gas and evaporates. It pulls heat from the air to use as energy, which powers the transformation from liquid to gas. The gas absorbs the heat, and a fan blows the cold air it produces around the room.
If it’s a combined air conditioning and heating system, this process can simply be reversed. All that’s needed is a reversing valve, which reverses the flow of thermal energy; the hot condenser becomes the cold evaporator and removes the cold air, pumping the warm air into the room.
What Are The Benefits Of A Combined Air Conditioning Unit?
There are lots of benefits to installing a combination heating and air conditioning unit. Of course, the main benefit is that you can heat as well as cool your home. But what about the benefits of other air conditioning systems? Here’s a quick run-down of the advantages of a split or multi-split system:
- Climate control
With a multi-split system that offers combination heating and air conditioning, you can control the temperature of different parts of your home or business premises. You can heat or cool different areas as much or as little as you need to, ensuring that you’re always comfortable whatever the weather outside.
- Efficiency
Heating and air-con systems are efficient. This is mainly because they don’t use ducts to push air around your property. Ducts lose heat on cold days and get warm on hot days, whereas split or multi-split systems use refrigerant pipes and pressure to heat or cool, making it more efficient.
- Cheap to run
Combined heating and air conditioning systems are a good option for heating your home, especially if you don’t have a mains gas connection. Electricity powers them, making them cheaper to run than oil boilers. Plus, if you pair a combination air conditioning installation with renewable energy, you could pay next to nothing to run your system.
Pair Your Combination Air Conditioning System With Solar Panels
A great way to reduce your running costs and do your bit for the environment is to power your heating and air conditioning units with solar panels. Solar panels generate electricity from the sun, then distribute this electricity to the appliances in your home. Depending on how many solar panels you get and the amount of electricity you use elsewhere in your home, you could power your air conditioning system for free.
Who Needs To Carry Out A Heating And Air Conditioning Service?
Combination heating and air conditioning units still have the same components as normal air conditioning units, so an F-gas registered engineer needs to service your unit. If released into the atmosphere, the refrigerant in a heating and air conditioning unit can be extremely harmful to the environment, so it’s important to have your system serviced by a qualified engineer that can take all the necessary precautions.
During a heating and air conditioning service, the engineer will:
- Check that your system is still healing and cooling efficiently
- Clean indoor and outdoor units
- Inspect air filters, coils, fans, compressors, and any other components
- Check all electrical connections
- Test for refrigerant and oil leaks
- Ensure your system is still compliant with F-Gas regulations
If everything is still working well with your air conditioning unit, it will be a simple and quick appointment. However, if your heating and air conditioning service flag up any problems, your engineer will advise you on what should be done to fix them. If you have regular services, hopefully, any problems will be identified and can be fixed easily at a relatively low cost. That’s why it’s important to keep up with your services, as they could save you money in the long term.
Get Advice Before Investing In Combined Heating And Air Conditioning
It’s best to do lots of research and get some professional advice before buying any type of air conditioning system. We’ll be able to tell you the best system to install on your property based on how big it is, and what systems you currently have in place, and give you an idea of the cost.
