Central air conditioning systems are what are used for large buildings, their compressors and injection fans are large enough to move large air flows. by Víctor Alejandro Galvis González
Thanks to the challenges that the air conditioning industry has in the ecological, electronic and efficiency field, in recent years significant advances in equipment technology have been developing, so much so, that if we compare the current equipment with those used a decade ago, we can notice a great change. In this context, when the technological range is deployed, the vision of each sector of the industry also does. In large infrastructures, for example, the installation of the right technology is as vital as its size and more so when the investment demanded by this type of project is of colossal proportions. The work of cooling buildings such as hospitals, factories, banks, shopping centers and in general large buildings, is not in a few hands. Selecting the right air conditioning system depends on designers, architects, engineers, manufacturers, installers and of course, the institutions involved. It is illogical that a newly built building has to invest in retrofit a few years after its birth, so most central air conditioning systems, those used for large infrastructures, are incorporated into the building when it is under construction. As Giovanni Barletta, technical manager for the Andean and Caribbean region of Emerson Climate Technologies, points out, before starting the air conditioning of a place like these "you have to know the detail of the construction, materials, conductivity, colors, occupation and a good database, as accurate as possible, of the possible profile of exterior temperatures and with it the thermal load profile". However, it is not enough to have a unique value of environmental conditions, "it is necessary to know how these vary during the year, and not only in temperature, but in relative humidity, winds, etc.", explains Giovanni Barletta. Zoning, temperature and humidity outside are three determining concepts for the design of each system, consequent to this and having a guarantor panorama gives way to the analysis of other factors. Some of the issues that must be taken into account in a study prior to the installation of a system for large buildings is the "meeting of all the components that affect the air conditioning system, control areas and their specific requirements: temperature, humidity and exteriors," explained Sergio Quintanilla Scott, general director of TTQ, company dedicated to the installation of industrial air conditioning systems. Likewise, the engineer Quintanilla highlighted aspects such as outdoor air (changes per hour), circulation, pressurization (negative or positive), filtration levels, studies of thermal loads of each area and block, study of use and diversity factor, selection of equipment, trajectory of pipes and ducts and preparation of construction plans. The challenges posed by these projects
Large buildings demand difficulties as great as their size. In the case of its air conditioning systems, one of the biggest challenges remains the Kw/Tr efficiency; In addition, companies are increasingly aware of energy savings and request high-efficiency equipment within each type of system. Even so, other factors such as noise, space and areas of maintenance and operation, remain constant challenges in the installation of central controls; as well as, "the height pressure (water column), the variation of production vs. demand (creating a variable system) and the variety of areas of use and different requirements all the time", are, according to the engineer Quintanilla, continuous challenges. Without forgetting that it is necessary to "distribute equitably the electricity consumption of the plant among all users, partial and / or minimum loads", concludes the TTQ engineer.
Following this line, Giovanni Barletta states that "the biggest challenge is to be able to combine in a single response and an integral solution the expectations of the environment, efficiency, low noise levels, connectivity to other intelligent systems of the building, ability to adjust to a wide range of variability of loads and world-class after-sales service". Maintenance is essential
Taking into account the importance that maintenance has for the proper functioning of any system, Javier Páez, sales manager of the distributor channel of the company Climate Solutions, shared some recommendations for the maintenance of slipt systems. - Maintenance should be done at least twice a year, once at the beginning of the hot season and once at the beginning of the cold season (if the equipment has heating). - The maintenance must be done by trained personnel and basically consists of cleaning the inner and outer coils, checking the electrical parts and checking the refrigerant gas pressures to check that there are no leaks in the system. It is important to clarify that the user must frequently clean or replace the air filters, usually once a month. However, not all installations are subject to the same requirements and from these derives the true maintenance plan that must be focused on energy efficiency, that is, those routines that guarantee that the consumption variables of the equipment remain constant as they were conceived by the design and during commissioning. Preventive maintenance will also depend on the type of equipment and the recommendations of each manufacturer, as well as the periodicity. Engineer Quintanilla highlighted some factors that affect the equipment: "The lack of preventive maintenance, not having the spaces required for its correct operation (clearance)", in addition, "lack of space for the correct development of maintenance, exposure to toxic or dirty places and continuous or very forced operation", says the engineer according to his experience. Updating of the systems
There are many equipment that the market offers to the industry as far as air conditioners for large installations are concerned, but the demand of each establishment is different, the central controls and frequency inverters change according to the type of operation modulation that each system demands. "Splits are systems that are hidden, therefore they are more presentable in a commercial premises, they can also distribute the air better in the conditioned space thanks to the network of ducts that must be installed. For all these are systems that involve a higher initial investment," says Javier Paéz, from Climate Solutions. Giovanni Barletta, for his part, says that "among the most outstanding changes I highlight the need for systems to be regulated to their minimum expression, reaching up to 10% even, depending on the local thermal load. The method of turning the compressor on and off, which was called the technology of the "digital compressor", which with a simple mechanism of charging and discharging from zero to 100% in cycles of 20 seconds manages to finally vary its capacity from 10 to 100% and in that portion the energy consumption ". This concept gave rise to what we know as VRF systems (variable refrigerant flow systems) and a whole trend of new schemes and applications. It is pertinent to clarify that the needs of each building are different and this translates into a particular air conditioning system for each one. Central air conditioners for country (rural) clubs, churches, theaters, music halls, factories, shops, food and beverage establishments. In general, the central controls must be easily adjustable and automatically controllable, they must not cause harmful gases, for which there will be adequate air renewal in the premises. The entire installation of central air conditioning, cooling or heating, as well as operation and maintenance must be with the lowest possible energy consumption.
