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Applications of evaporative cooling in hospital centers
The evacuation of the condensation heat required by the refrigeration processes in large socio-sanitary complexes, be it hospitals or geriatric residences, finds in evaporative cooling an optimal combination in terms of energy savings and costs. This technology becomes a safe and effective alternative in this type of surfaces.
The operation of equipment such as evaporative condensers and cooling towers is based on a natural process that uses water as a refrigerant and is applied to the transmission of excess heat from different processes and thermal machines to the atmosphere. However, the consideration of these equipment as facilities for legionella transmission risks has generated doubts among those responsible for the design and construction of the socio-hospital facilities around the problems that the bacteria could cause in immunosuppressed people or in elderly people with pictures of multiple ailments.
The ignorance and social alarm, often unjustified, that revolves around the sources of transmission of the bacterium Pneumophila Legionella has questioned some equipment that is, without a doubt, the best technical solution and that, with the correct maintenance and Design measures implemented by all manufacturers eliminate the risk of legionella transmission.
At this point it is worth remembering that, in the same way that has been happening in recent years, in 2018 there have been no cases of Legionella linked to cooling towers and evaporative condensation equipment. The investigations of environmental and epidemiological character, as well as the inspections carried out in the facilities of risk, have shown the non-connection between the outbreaks and this type of equipment. On the other hand, most of the registered cases have their origin in the water network, something that confirms one of the main demands of AEFYT, which has always recommended an exhaustive control of the water supply network: a colony Legionella Pneumophila virulent access to any place with a certain concentration of water through the network, so that control of its origin is essential to avoid outbreaks. This water reaches places as close to citizens as sprinklers, swimming pools or public fountains
On the other hand, the evaporative cooling equipment is completely safe just by adhering to the maintenance established by current legislation (Royal Decree 865/2003, of July 4, which establishes the hygienic-sanitary criteria for the prevention and control of legionellosis), which determines the basic maintenance conditions that must be followed to ensure environmental safety. Manufacturers’ maintenance recommendations take these standards as a basis, although in many cases they are extended and improved not only to avoid the risk of bacteria proliferation, but also to ensure an optimal state.
Evaporative cooling is a safe, efficient and economically and environmentally sustainable technology. There have been several factors that are helping society to become aware of this reality:
- The increasing commitment of installers and owners with the control, maintenance and inspection of these facilities.
- The effort made over the last few years to guarantee the safety and efficiency of this technology.
- The change of attitude experienced by the regional administrations of Environmental Health, which stopped referring to such equipment as the only cause of the proliferation of the bacteria and have begun to consider the rest of risk facilities -public fountains, irrigation systems, spas , swimming pools, vaporizers, hot sanitary systems, etc. – and, consequently, to take more appropriate measures against this problem.
Operation and applications
The evaporative cooling equipment, used for the condensation of the refrigerant gas in the refrigeration facilities, releases the condensation heat from the refrigeration machines, transferring it to the atmosphere by evaporating a small amount of water. This process becomes effective thanks to the establishment of the contact between the circulating water and an air current in a heat exchanger. The added value of this technology goes through being natural, simple, clean, safe and economical and it covers three large areas: the socio-sanitary, destined to eliminate the risk of Legionella transmission; the environmental, linked to energy efficiency; and, finally, the economic one, thanks to the optimal relationship they offer between cost (including installation and maintenance) and energy consumption.
In the first of these points, the objective in the design and maintenance of evaporative cooling equipment is focused on eliminating any risk of transmission of the bacterium Pneumophila Legionella. This is achieved, simply, with the fulfillment of the installation and maintenance requirements collected in R.D. 865/2003, of July 4, on legionella prevention. Its application would be enough to guarantee the social-sanitary security but the manufacturers of cooling towers and evaporative condensers have gone further.
Good design and correct operation of the cooling installation are based on the following principles:
- Avoid conditions that favor the multiplication of bacteria with proper cleaning and maintenance of the equipment, as indicated by the Law.
- Minimize the dragging of water aerosols in the air discharge of the equipment with the available technologies and that we will see later.
- Reduce the possibilities of inhalation by people through the proper placement of the equipment.
- Adequate design of the installation: all the equipment has drop separators that avoid this risk and, in addition, they must be placed where the discharge of the aerosol can not enter directly through the windows or the air intakes of neighboring buildings.
Currently, all manufacturers of refrigeration equipment with evaporative condensation offer efficient systems for maintaining the water circulating in the towers, as well as cleaning and controlling them. Also, the protection systems that are included in the facilities themselves are increasingly sophisticated, so the risk is practically non-existent.
In summary, in the case of the evaporative cooling towers, the solution is not to limit the use of all these equipment and facilities, but to provide engineers and owners with the necessary protocols and tools to avoid the presence of the bacteria, its proliferation and its diffusion to the environment, as well as in carrying out, as established by legislation.
Technological advances and increased security
The latest advances in terms of materials and design that have incorporated these equipments constitute another security guarantee. Among them, the following stand out:
- Materials: its evolution has focused on high-efficiency fillers with the use of materials, mainly polypropylene and polyester, which offer great resistance and allow for severe cleanings; Another component of the tower in which the materials have improved are the high-efficiency drop separators, which have undergone a similar evolution in terms of composition and effectiveness when it comes to preventing water droplets from escaping outside the tower. The latter is a critical aspect when transmitting possible colonies of bacteria to the atmosphere. There are serious doubts that the bacteria, if found in water, can survive in the microdrops that constitute the aerosol that eject the equipment.
- Accessibility: correct accessibility is one of the best guarantees that the cleaning of the tower can be carried out correctly.
- The systems to facilitate drainage, cleaning and sampling are carried out with inclined trays, platforms and stairs which, in addition, it is important to point out that they meet the most stringent standards in terms of occupational safety.
- Windows: its design prevents the passage of light or water that carries dirt. Preventing the passage of light is especially important to prevent ultraviolet rays from causing the necessary conditions for microbiological development inside the tower. This is precisely one of the great advances experienced in recent times: the sealing of the windows is a guarantee of safety and proper functioning of the equipment.
Control y Ventilacion, S.L. is a company of international renown within the industrial and livestock sector, for being a manufacturer of products within the evaporative cooling sector, such as the HUMIBAT, evaporative plastic cooler; or its NUCLEOS towers, Cooling Towers. In both products, the substrate in which the evaporative process is produced is a plastic honeycomb, a honeycomb resistant both to physical and chemical attacks, and at the same time flexible, a honeycomb with a mesh structure, made of polyethylene High Density, and marketed under the names of PANAL C & V or in the case of being a drop separator, SEPARADOR C & V .
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