HVAC (Heating, Ventilation, and Air Conditioning) systems are a group of air conditioning equipment that allows for maintaining a pleasant temperature in a living space. But this equipment also controls the purity and humidity of the air to avoid respiratory problems in people.

The HVAC air conditioning system is used in large residential buildings, hotels, hospitals, cinemas, theaters, offices, etc. Although these systems come with their basic sensors for equipment control, they have currently integrated into Internet of Things (IoT) technology. IoT technology allows more efficient control of the entire air conditioning system since more information is available for its control.

What are the parts that makeup HVAC systems?

HVAC systems must provide air conditioning in both winter and summer. For this reason, these systems need to have a heating unit and a cooling unit. In addition, they also have an air handling unit, which will be in charge of cleaning the air and distributing it in the spaces to be conditioned.

HVAC systems heating unit

Heating can be obtained from natural gas boilers, electric resistances, and heat pumps. Gas boilers and electric resistances are preferred in very cold areas. However, heat pumps are more effective in temperate climates.

Gas boilers work by heating water to a temperature of 80 degrees Celsius, which will be used to heat the space to be heated. This hot water can be stored in thermal tanks, and then pumped to each part of the building.

When electrical resistances are used, they can be placed directly in the spaces to be heated. This air conditioning alternative has the advantage that electrical energy is carried to the resistances, using electrically conductive cables, without major inconveniences.

On the other hand, heat pumps are electrical equipment that works by taking advantage of the thermodynamic cycle of gas, to absorb heat from the outside environment. This heat is then transferred to the space to be heated.

HVAC systems cooling unit

The heat pump in cooling mode is the air conditioning system that is universally used to generate cold in summer. This is an electrical device made up of a compressor, an evaporator, a condenser, and an expansion valve. Within the heat, the pump circuit circulates a fluorinated refrigerant gas, CO2 or ammonia, which are gases with excellent thermodynamic properties.

Large HVAC systems use cooling towers to facilitate heat exchange between the interior of the building and the environment. Without an efficient heat exchange, the air conditioning of buildings would be impossible.

Air handling unit in the air conditioning system

Ventilation systems are an indispensable part of HVAC air conditioning. These are made up of ventilation ducts, forced draft fans, heat exchangers, filters against dust, bacteria and viruses, ambient air intake, etc.

The air handling unit (UMA) is a closed structure, within which all the conditioned air that enters and that is extracted from the building, house, hospital, etc. is controlled. UMAs are comprehensive ventilation systems that guarantee purer air free of high concentrations of CO2, bacteria, bad odors, dust, spores, humidity, etc.

Inside the UMA there are two heat exchangers, one for heating and the other for cooling. That is, one heat exchanger receives only hot water from the gas boiler and the other receives refrigerant gas from the heat pump. Finally, these ventilation systems use a fan to force air through the heat exchangers, accelerating heat transfer.

The structure of the UMA, in the HVAC systems, has four points for the access and exit of air. Two of these points are for the outlet and return air conditioning of the building. And the other two are used for the intake of fresh air from the outside and for the exhaust of air with a high CO2 content from the building. These last points have a mechanism that regulates the entry or exit of air, in a continuous interval between 0 and 100%.

Control and sensors of HVAC ventilation and air conditioning systems

Control in HVAC systems begins with the air temperature, through the use of digital or analog thermostats. In addition, relative humidity sensors, differential pressure sensors, and CO2 concentration sensors are also used.

All these sensors send information to a logical process controller, which is programmed to take the relevant control actions. If the temperature is above the thermostat setting, the controller will reduce the boiler flame or activate the refrigerant gas compressor. However, when the air temperature is below the thermostat setting, the controller will do the opposite of what was mentioned above.

When the CO2 sensor detects an abnormally high concentration of this gas, the controller opens the fresh ambient air intake. In addition, it also opens the outlet that allows part of the stale air inside to escape. This action decreases the concentration of CO2.

The differential pressure sensors make it possible to detect when the dust filters are clogged with dirt and also if any draft fan is off. On the other hand, the humidity sensors allow to detect when the air has a lot of humidity, which automatically activates the dehumidifier of the HVAC system.

Smart buildings and HVAC

The evolution of Internet of Things (IoT) technology has increased the possibilities to automate and make processes more efficient. The internet of things has allowed the creation of smart homes and buildings, which provide greater comfort, efficiency, and security to their inhabitants.

HVAC systems in smart buildings are more efficient since new technologies allow remote supervision and operation of the same. In addition, the Internet of Things allows the operation of the air conditioning to be adapted to the number of people who inhabit the building, routines, habits, etc.

With IoT technology, many devices around us are not only smarter and more interconnected, but have incorporated a wide variety of very useful sensors. Among these sensors we have the following: accelerometer, infrared, proximity, light, ultrasound, pressure, electric current, etc.

Intersam, a company specializing in air conditioning systems

At Intersam we have more than 25 years of experience in refrigeration and heating systems, in industrial and commercial applications. HVAC systems are complex air conditioning installations, which require the intervention of specialists from different areas. In this sense, Intersam offers a specialized service in the field of heat exchangers, condensers, evaporators, dry coolers, and airflow treatment.

If you are interested in installing an HVAC system or have problems with it, do not hesitate to contact us. We work with highly trained engineers and technicians to guide you and solve your problem.