Monthly Archives: June 2019

Ventilation system of commercial building

The ventilation system in commercial building performs the functions of cleaning the air from dust and other small particles, localizing and removing odors, and creating a comfortable micro climate. Ventilation in sales areas, shops should be low noise, if possible hidden from the eyes of visitors and easy to maintain.

Design features

The design of the ventilation system for commercial building is similar to the ventilation design of administrative, industrial buildings. However, the specifics of commercial enterprises determine some important, mandatory conditions.

If the retail space is divided into several shops, each of them should be separately regulated ventilation channel. This allows you to avoid mixing smells and set your micro climate in each individual room, depending on the load.

In shopping centers, air conditioning is mandatory.

The store should have its own autonomous ventilation system, even if it is located in a house, large office or manufacturing center. It is not allowed to connect the air ducts of the sales area with the ventilation system of the entire building.

The area of the retail space directly affects the type of ventilation system to be installed.

The supply and exhaust ventilation system is equipped with fans, which make it possible to regulate the flow and discharge of air in all weather conditions.

It can be supplemented with an air heater, air cooler, various filters, dryers and humidifiers.

Ventilation systems allow you to create a comfortable micro climate. Such a system is suitable for large trading rooms.

The central ventilation and air conditioning system is an extensive network of small supply and exhaust systems that are interconnected. To cool the air using water or freon. Cooling systems can be roughly divided into two main classes: water – chiller-fan coil and freon – VRV and VRF systems. As a rule, they are installed on the roof of the building or next to the building. This centralized ventilation system is designed for buildings where it is necessary to regulate the micro climate and clean air separately in each room. It is used, as a rule, in large shopping centers, where cafes, restaurants, shops, including perfume shops, are located nearby, and each of them represents a separate room.

Design and calculation

Data required for calculation in the design of ventilation of commercial premises:

The location of the building, its windows, doors relative to the cardinal points, the climate. A large role is played by panoramic windows and roofs.
Type, lighting power and heat gain from it.
Availability of equipment in the sales area and how much heat it emits during operation.
The functionality of the room. Will there be a bakery, cafe, outdoor perfumery, household chemicals or other odorous goods in the sales area?
The number of employees and the average number of visitors.

The specificity of the calculations of ventilation for commercial building is that it is almost impossible to calculate the exact number of people in the store. They come and go each at will at any time. For calculations, take the average accepted values of the density of the number of people for different types of retail premises:

1 person on 6 square. meters – for bookstores, sporting goods, equipment, electronics, furniture and jewelry stores;

1 person to 5 square. meters – for all other types of stores, including grocery.

The number of employees in the store is a fixed number. For supermarkets also take the average number of staff:

1 employee per 100 square meters- for a grocery store.

1 employee per 160 sq. M. meters for all other types of self-service stores.

The calculation of the ventilation system consists of the following steps:

Determination of parameters of external air in the cold and warm period of the year. Selection of air characteristics in the room, taking into account the functionality of the room.
Calculation of heat loss through the walls, windows, doors, fences.
Calculation of heat gain from equipment, people, lighting, heating, from the sun.
Determining the amount of moisture that enters the air from people in the room, hot products.
Taking into account the data obtained, the value of air exchange is determined, which is necessary to maintain optimal parameters of temperature and humidity in the room.
Separately, air exchange is considered for a bakery and a cafe, if they are provided for in the sales area.
Aerodynamic calculation. It allows you to determine how much air pressure drops when passing through all ducts. This value affects the speed at which air will flow into the room.

All calculations are made separately for the cold and warm seasons. In some regions, the transition period is included in the calculation. It is characterized by high humidity and strong temperature variations during the day.

After determining the required values, proceed to the design of the ventilation system. Its effectiveness depends largely on how well the air exchange is organized, whether the air is evenly distributed throughout the room, and whether a comfortable micro climate is created.

For the selection of ventilation equipment developed special programs. The necessary parameters are introduced, the calculated values for which the program selects the units that match each other.

Installation of the ventilation system is carried out by the specialized organization. A schedule is drawn up according to which construction and installation works are underway. After complete assembly, the ventilation system is tested at various loads. If the results are positive, the installation of ventilation is considered completed.

Ventilation system of industrial buildings

The specificity of industrial buildings in their multi functionality. It can be small workshops, warehouses, administrative and technological premises, industrial workshops and laboratories. In each case, their own requirements for the ventilation system.

The design of Ventilation system takes place at the stage of creating the construction project of the entire building and according to clearly defined parameters. Even at the stage of project creation, the functionality of the premises and the tasks to be performed by the ventilation system are determined.

Warehouses. In most cases, the room is equipped with a natural ventilation system. It is the least expensive. Air exchange occurs in a natural way, as through an open window. But for the storage of many foods, fruits, vegetables, medicines, it is necessary to maintain a certain temperature, humidity. In some cases, such as when storing batteries, an explosive gas is released, which must be constantly removed from the room. Such warehouses are equipped with a supply and exhaust ventilation system with air conditioning.

Administrative and technological premises. These include high-tech workshops and rooms with control panels. Modern sophisticated electronic equipment for smooth operation requires maintaining a certain microclimate. The same requirements apply to the air in administrative premises, offices. In these cases, a standard supply and exhaust system with basic air purification filters is used.

Laboratories. Microclimate requirements in laboratories are similar to requirements for administrative buildings. The exception is medical facilities and research when the formation of harmful gases. In these cases, special filters and the possibility of more flexible control of temperature, air flow and humidity are required.

To remove harmful gases and bacteria, to prevent the development of mold, local fume hoods should be provided, which should be linked to the general ventilation system to compensate for the amount of exhaust air.

Workshops. These production facilities are usually small in size and with a minimum number of employees. There is enough installation of supply or exhaust ventilation. If the work of the workshops is associated with the release of harmful gases, dust or other small mechanical impurities, a more powerful exhaust ventilation system and additional air purification filters are installed.

Industrial shops. As a rule, the central ventilation system is used, the main units of which are located on the roof or in a special room, the air enters the shop through an extensive duct network. The air conditioning system is installed only where it is economically justified.

In industrial workshops it is possible to supply the supply and exhaust channels to each workplace. It does not allow gas, dust, which are formed during work, to spread throughout the room.

The main parameters in the calculation of the ventilation system of industrial buildings:

The size of the room, its geographical location.
Category of work.
Type of production.
Number of employees.
The duration of stay of employees in the room.
The location of jobs.
Total load of each room in the building.

The design of the ventilation systems of industrial buildings is of three types.

Local – installed in small rooms.

Central – used for large rooms, workshops, warehouses. It has a single control center. Central systems can be with or without the possibility of flexible control of air parameters for each room or workplace. Central systems with the possibility of flexible control of air parameters for each room are called VAV systems, with variable air flow.

The ventilation system can be equipped with air conditioning.

The emergency ventilation system works only for air outflow, removal of smoke and gas. Emergency ventilation is activated automatically when necessary.

Core modules

The ventilation system has a modular design. The availability of modules depends on the tasks that are put in front of the ventilation system in each particular case.

Filters for air purification. Virtually any ventilation system is equipped with a cellular or pocket dust filter. Through it passes both outside and recirculated air. Antibacterial, adsorption filters can be installed.

Air heaters. Used ventilation systems for heating the air in the cold season.

Air coolers. For large industrial buildings, water or freon heat exchangers are used as an air cooler.

Humidifier. After cooling, the air drains significantly. To maintain the desired value of humidity using the chamber irrigation or steam humidifier.

Fan for forcing air through ducts.

Sound attenuators. To reduce noise from ventilation can be installed mufflers.

Installation

Installation of the ventilation system occurs during the construction of the building. It is also possible to install a new ventilation system on an old building. This is a more laborious process.

The main stages of installation of the ventilation system:

Laying of pipelines, air ducts;
Installation of valves, pressure regulators;
Installation of system units: fans, coolers, heaters and others;
System test.

After complete assembly of the ventilation system and the availability of the building, three tests are carried out. They are attended by a representative of the organization that was engaged in assembly and installation, a representative of the general contractor and a representative of technical supervision.

The big dilemma of HVAC repair or replacement?

A safe, efficient and reliable HVAC system is the key to creating a comfortable environment in any room, be it a residential, industrial or commercial building. Of course, any climate system needs timely maintenance and repair. Therefore, when it begins to show signs of wear, or when its service life comes to an end, perhaps you are asking yourself whether it is worth investing in its repairs or is it better to simply replace it with it? In this article we will try to answer this eternal question.

There is no obvious solution here. Whichever option you choose, it takes a lot of effort to get the HVAC system up and running. To help you make the right choice, we have compiled a list of important factors to consider.

Age of the HVAC system

The service life of the climate system depends on its size, serviced area and purpose of use. Nevertheless, as a rule, it is considered that 15–20 years is the period after which it requires replacement. Naturally, before you decide to upgrade or repair, it is better to conduct a professional assessment of the condition of all components of the system – especially if its annual inspections were not conducted during operation.

Many obsolete components, refrigerants and gases used in climate systems are removed from production in favor of more environmentally friendly counterparts. Consequently, spare parts for outdated systems may be scarce and expensive.

Cost of

One of the factors that any building owner or management company considers is the cost of replacement compared to the cost of repairs. There is one good rule here: if the cost of repairing equipment is more than 50–60% of the cost of a new one, it’s time to change it.

Naturally, budget considerations should also be taken into account, but it should be borne in mind that the new HVAC system will last much longer than the one that was simply repaired.

Energy efficiency

Energy efficiency is a hot topic in the HVAC industry. Manufacturers and suppliers have made tremendous efforts to offer customers more and more efficient systems. Due to its design features and used components, older systems are much less efficient than modern ones.

If you notice a decrease in performance or the absence of any noticeable improvements with a rising cost of operation, this means that, most likely, the system has become ineffective. Low efficiency not only harms the environment, but also lowers the comfort of building conditions, as well as inflates monthly bills.

System performance

The performance of an HVAC system is directly related to its energy efficiency. The main purpose of climate systems is to ensure indoor air quality (IAQ), which is achieved through proper ventilation and air filtration, as well as maintaining temperature conditions.

A low IAQ is associated with a number of ailments that adversely affect the quality of life, productivity, etc. These can be allergic reactions, nausea, asthma attacks, headaches and, in the worst cases, serious chronic diseases.

In this case, the new system must be installed as soon as possible.

Internal factors

Perhaps the building has a team that serves it. In that case, talk to her. This can give you a more complete picture of the state of these systems and will let you know if replacement is the preferred option.

The decision to replace or repair may be dictated by company policy. Sometimes this policy states that repair is a priority option, and this is usually determined by budget considerations. Full replacement of the system may require funds allocated for several years of operation, but when the life of the components comes to an end, the problem should be considered in the long term.

As you can see, the choice between repair and replacement is not an easy decision. Nevertheless, a lot of things speak in favor of installing a new, modern HVAC system. Energy efficiency and low operating costs are likely to compensate for initial costs.

Maintenance and Repair of Ventilation and Air Conditioning Systems

The process of ventilating the room is accompanied by a complete replacement of the air in it (additionally cleaning, drying, heating, cooling, ionization, etc.). The process of ventilation of the premises is implemented using special modern equipment, which is responsible for maintaining the required level of humidity, temperature and cleanliness. In order for the equipment to serve properly and the repair of ventilation systems does not become the main expense item, it is necessary to maintain the systems in a timely manner.

Tracking device operation parameters and quick troubleshooting will prolong equipment life, as well as create comfortable conditions for being in the room.

The variety of types of ventilation and refrigeration equipment, the complexity of their internal assembly leads to the fact that the maintenance of air conditioning and ventilation systems at least once a year is a necessary necessity. With the observance of the rules of operation and timely professional diagnostics, the equipment will serve without complaints for many years.

Why is it important to maintain air exchangers?

Regardless of which room is in question, public or private, clean air and its active movement are crucial factors. In modern construction, modern materials are used that provide minimal heat loss in the cold period of the year or heating of buildings in the warm season through enclosing structures. Thus, more and more buildings are sealed and “do not breathe”, thereby creating the unpleasant sensations of a long stay in a confined space. That is why it is important to maintain the air-exchange equipment in a functional and in good condition, as well as to timely maintain the ventilation system.

The statistics confirms that in case of poor air circulation in the working room, the efficiency of the personnel drops noticeably and the number of sick employees increases. It is impossible to trace this connection directly, since air conditioners and ventilation continue to work for the first time after installation without qualified service – outwardly it will not be obvious that they need professional debugging. But in a contaminated installation, pathogenic bacteria are rapidly developing, and simple diagnostics of ventilation and air-conditioning systems will help specialists quickly identify and select the list of appropriate repair procedures.

Professional assistance and maintenance includes:

checking and replacing filters;
performance check and heat exchanger cleaning;
control of the amount of refrigerant;
cleaning and lubrication of machinery parts;
performance check electronic control.

To ensure proper operation, the initial design and installation of ventilation and air conditioning systems must be carried out by professionals. In the future, qualified assistance may be needed in the following cases:

problems in the operation of automation in the operation;
redevelopment of premises (redistribution of air flow, movement of exhaust umbrellas, balancing the system);
clogging filters, grids;
clogging of heat exchange equipment
imbalance or improper operation of actuators

Types of repair and maintenance work

Depending on the procedures used, the maintenance of industrial ventilation and ventilation of residential buildings can be divided into several groups.

Service, as a rule, is carried out twice a year and includes the following procedures:

check for dents, chips that affect the operation of the device damage;
inspection of the fan, cleaning of dirt and accumulated dust;
impeller balancing check;
measuring and controlling the noise level, identifying the causes of its occurrence;
adjustment of belts and their tension;
flushing heat exchangers;
maintenance of automatic ventilation systems;
inspection and cleaning of the internal surfaces of all sections of the unit;
tightening electrical connections and other maintenance and repair work.

Maintenance for air conditioning equipment is divided into the following types:

clearing the drainage system;
checking the level and pressure of the refrigerant;
carrying out planned work to prevent possible damage, and test the device in all modes;
cleaning of internal filters and heat exchangers;
search for refrigerant leaks and fix them when detected;
setting overheating temperature and checking its differences on the indoor unit;
pulling and maintenance of electrical connections and other procedures.

When the state of technology is not determined, and there are problems, a special expert assessment is needed. If the design, installation and maintenance of ventilation and air conditioning systems were carried out by professionals, then determining the cause of the breakdown and quickly developing a repair plan will not be difficult.

Cost of services

It is not recommended to neglect annual preventive maintenance of air exchange equipment. Even if outwardly it seems that the system is in good condition, without timely maintenance, it will fail much faster than provided by the operating documents.

The cost of maintenance depends on the intensity of use of devices, as well as on the main characteristics:

installation site;
configuration;
past service life.

Three types of HVAC condensers

Condenser is a device used to liquefy gas by cooling it. In the HVAC equipment, the hot gas (vapor coolant) from the compressor enters the condenser coil at the top and condenses, proceeding from the condenser to a receiver located near the bottom. The capacitor coil is located along with the compressor and control devices in the condensing unit. In the air-conditioning system with a remote or split system, the condensing unit is located in the open air. Capacitors are available in various sizes and designs, which include tubes with conventional tubes, ribbed tubular and plate, serial and parallel blocks.

Condensers are classified according to the cooling method. The three main types are broken down into:

Condensers with air cooled
Condensers of combined air and water cooled
Condensers with water cooled

Condensers with air cooled

The air cooled condenser consists of a coil of sufficient surface that air is blown by a fan or caused by natural draft. This type of capacitor is universally used in small refrigeration units.

Air-cooled condensers should be kept free of dirt, nap, and other extraneous materials, as they tend to reduce the air flow around pipes and fins if they are allowed

Combined condensers with air and water cooled

This type of condenser is also known as an evaporative condenser and consists of a coil, cooling water. Sprayed from above, and then cold air enters the bottom and is injected through the coil. When water evaporates from the coil, it creates a cooling effect that condenses the refrigerant inside the coil. The refrigerant gas in the coil is hot, which has changed to a liquid state, combining the scattered water and a large column of moving air supplied by the fan. The water that does not evaporate is recycled using a pump.

Condensers with water cooled

A water-cooled condenser is similar to a condenser on a steam surface. Cooling is carried out only with water circulating through tubes or coils enclosed in a shell. In a water cooled condenser, the refrigerant circulates through the annular space between the pipes or coils. Through its design, a water cooled condenser is also referred to as a two-pipe capacitor.

Since the evaporative condenser is not wasteful to water, large compressor units are available in areas where there is little water. Tests have shown that the amount of required water will not exceed 0.0 gallons per minute per ton of cooling. This is one of the eco-friendly reasons for using a condenser of this type. Evaporative condensers also eliminate the problem of water removal and provide the most economical ways to cool refrigerant gases of standard air conditioners.