Читать онлайн Alexey Antipov - Installation, starting and adjustment of ventilation and air conditioning systems A Guide

Many people believe that the main motivation In any professional field is earning money and promotion at work. On the one hand, these are really the main Motives for people to work every day ( sometimes through force) why people go to work every day (not always the favourite one). However, we can find many people Who are unassuming and work for lower fee being completely satisfied with their job works for less salary because they are beloved with their job. So what motivates a ventilation engineer to work in this sphere?

American psychologist Abraham Maslow has identified deep motives common to all people that determine human behavior.The psychologist believed that physical survival is the first deep motive and basic human need. After he is satisfied, the person will switch to the next need. As soon as it is completed, it is the turn of the next one, there are only five main motives:

These include air, food, drink, shelter, clothing, warm, sleep – everything that is necessary for human survival. Maslow included sex in the same group. The psychologist considered these needs to be the most important – in a situation of extreme need, a person, first of all, will think about how to survive, that is, about physiological needs. Until they are satisfied, it is unlikely that he will have other desires.

As soon as the physiological needs of a person are satisfied, the desire for security and confidence in the future come to the fore. People want to control their lives, see order and predictability around them. In society, this means the absence of direct threats to life and health, protection from natural disasters, social stability, financial security, and so on. The police, rescue services, medical and municipal institutions in general close these needs of people in society.

Initially, Maslow called them "the need for love." He believed that after satisfying physiological needs and obtaining security, a person expects love and affection from other people. This block of the pyramid includes social relations: family and relatives relationship, friendship, a sense of trust in others and acceptance of a person by others.

Maslow divided these needs into two types: self-esteem (self-esteem, personal achievements, independence from others) and to be respected by others. A person wants to feel important both in his own eyes and in the eyes of other people. Self-esteem is directly related to a sense of self-confidence and self-worth, with self-acceptance and self-worth. Respect from others is associated with the desire to be approved by others, successful and appreciated.

Maslow considers, that self – actualization is the ability of a person to do what he was created for. A musician feels the need to make music, an artist – to draw, a poet – to write. If a person wants to be happy, he must do what he was born for. This desire to develop one's potential is the highest need in Maslow's hierarchy. At the same time, the psychologist notes that the specific behavior into which this need will develop varies from person to person. For one, this will be expressed in the desire to become an ideal parent, for another it will be associated with sporting achievements, for a third it will be a joy to create or invent.

Fig.1. A. Maslow's pyramid of needs

To begin with, let's consider how much money you can earn constructing doing ventilation. That means we start from first stage.

Prices are given for September 2023.

HVAC repair costs will differ depending on the type of unit and how extensive the repair is. Here are some average service prices based on your HVAC unit:

If a component of your HVAC is starting to fail, you’ll need a replacement. HVAC companies will happily inspect your system and provide you with a quote for a part replacement. Here’s what you can expect:

From this table we can conclude that, any mater on Ventilation, can rise to the first step of the pyramid quite adequately. To master the remaining steps, we need to know the material outlined in the following chapters.

1. Name the five steps in the hierarchical model of human needs according to the theory of Abraham Maslow.

2. Evaluate the implementation of this model on the example of work in the field of installation of ventilation systems.

3. Give an example of self-actualization in your current profession.

4. Count the advantages of the profession of an installer of ventilation systems over other professions basing on of the above model.

5. Give a comparative analysis of prices (for example, the installation of fans) from several sources on the Internet. Formulate the cost structure of the service as you see it.

The state of the air is characterized by its main parameters: temperature, relative humidity, mobility (speed).

A person feels good only in a fairly narrow range of combinations of various air parameters.

The air parameters can be optimal, at which a person feels comfortable, and acceptable, at which a person's well-being and productivity of his work differs slightly from optimal. Thus, for industrial premises in the cold period of the year, the following optimal air parameters are set for medium-heavy work: temperature 18–20 °C, relative humidity 40–60% and mobility no more than 0.2 m/s.

The permissible air parameters for the same conditions have a wider range: temperature 17–23 °C, relative humidity no higher than 75% (the lower edge is not limited) and mobility no more than 0.3 m/s. In industrial premises, the maintenance of permissible air parameters is most often provided for.

Production processes may be accompanied by the release of harmful gases and vapors to humans into the air of the working area of the premises, the amount of which depends on the characteristics of the technological process, the degree of sealing of equipment, etc. The content of harmful gases and vapors in the air of the working area should not exceed the maximum permissible concentration (MPC). The maximum permissible concentration is the maximum possible amount of a harmful substance, mg/m^>3, per unit volume of air, which during the entire working experience does not cause diseases or abnormalities in the health of people working in these conditions, and does not affect subsequent generations. In addition, a large amount of heat, as well as moisture and dust can come from the process equipment. The person involved in the production process is a generator of heat, moisture and carbon dioxide. The heat output of one worker to the environment is 150–300 Watts or more. Every hour from 60 to 400 g of water vapor evaporates from the surface of the human body. Respiratory system produces from 20 to 40 liters of carbon dioxide.

These hazards in the form of excess heat, moisture, harmful gases and vapors enter the surrounding air and blendes in, while its temperature, moisture content, gas content, dustiness increase. This involves changes in the chemical composition and physical properties of the air.

In order to maintain normal air parameters in the premises that meet sanitary and hygienic and technological requirements, we implement ventilation, which creates an organized air exchange-removes polluted air and supplies treated (heated or cooled, humidified or drained) fresh and clean air instead.

Ventilation in most cases can provide only acceptable sanitary and hygienic conditions in the premises. The air parameters, strictly defined by temperature and relative humidity, including optimal ones, can be reached by using air conditioning systems.

Ventilation systems are divided into supply systems that supply fresh air to the premises, exhaust systems that remove dirty air from the premises, and air or air-heat curtains that prevent the penetration of cold air through the entrance or doors of buildings during the cold season.

Both supply and exhaust ventilation systems can be general and local type. General exchange systems are designed to supply and remove air evenly throughout the serviced room, to create an air environment with approximately the same parameters throughout the entire volume of the working area. Local exhaust systems remove the air in the places of formation of hazards from technological equipment, preventing the hazards from spreading throughout the entire volume of the room, polluting the entire air of the workshop. Local supply systems supply fresh air near workplaces, create an air shower or oasis – a restricted area in the production room where the parameters of the air environment meet sanitary and hygienic requirements.

Local exhaust ventilation is much more effective than central or general exchange ventilation, since it removes air from the places of formation of hazards with a higher concentration of them, does not allow the hazards to spread freely throughout the room, but such ventilation is not always feasible.

According to the method of air movement, all ventilation systems are either natural or mechanical.

In natural ventilation systems, air movement occurs due to the difference in densities of internal (heated and lighter) and external (colder and heavier) air.

In mechanical ventilation systems, air is moved by a fan or other equipment (a smoke pump, a blower, an ejector, etc.) driven by an electric motor. Mechanical systems are used much more often than natural ones, since the area of action of mechanical systems is much larger, and the cross sections of air ducts are smaller than in natural ventilation systems of the same capacity, due to higher air velocity. So, in the air ducts of natural ventilation systems, the air velocity is 0.5–2 m/s, and in the air ducts of mechanical systems 4–20 m/s.

During the operation of ventilation of any kind in the room, the air is forced to be changed. The ratio of the amount of fresh air supplied to the room for 1 hour to the internal volume of the room is called the multiplicity of air exchange. In real conditions, the multiplicity of air exchange can vary from 0.5 to 20 or more.

In addition to the designed air exchange carried out by ventilation systems, air can enter the premises by infiltration through leaks of windows, walls, doors, gates, etc. due to gravitational (natural) pressure and due to wind pressure. In the same way, air can be removed from the room.

If there are no harmful emissions in the room, then the supply ventilation systems are carried out in such a way that they take part of the air from the outside, and part from the room. This secondary use of air from the room for supply systems is called recirculation. It allows you to reduce the temperature difference between the supply air and the indoor air during the cold season, increase the relative humidity of the air and, most importantly, save heat (in winter) or cold (in summer).