Refrigeration evaporativa

The sector of the towers of refrigeration needs more support by part of the institutions. Like this it affirms it to Interempresas Manuel Lamúa, technical adviser of Aefyt and researcher of the Institute of Science and Technology of Foods and Nutrition (Ictan), the one who sustains that the current legislation is boosting the use of aerorefrigerators, that are “much less efficient energetically” that the towers of refrigeration, with the cost that this comports. “This is a reality that the society would have to know. Besides, the fear to the legionela is not founded, whenever it carry out a correct maintenance of these equipment”, aims the researcher.

The State Plan of Promotion of the Rent of Houses, Rehabilitation, Regeneration and Urban Renewal (2013-2016), approved by the Government the past 5 April, has like one of his arms executors the Program of Energetic Rehabilitation of Houses of the Institute for the Diversification and Saving of the Power (Idae), whose aim is the improvement of the energetic efficiency of buildings of new construction and of the already existent. The same foresee, among others, the realisation of measures of saving and efficiency on the envolvente and the thermal sensors installations of the buildings of residential use. It treats of an appearance in which the systems of refrigeration “would have to have a lot that say”, as it affirms to Interempresas Manuel Lamúa, technical adviser of the one of the Association of Companies of the Cold and his Technologies (Aefyt) and researcher of the Institute of Science and Technology of Foods and Nutrition (Ictan), a centre of investigation of own titularity of the State Agency Upper Council of Scientific Investigations (CSIC).

While many consider this energetic certification only a new form of, by like this say it, take out money to the individuals, for Lamúa is not it. “Near of 60% of the Spanish houses built without any rule of energetic efficiency (the first dates of 1979), by what Spain has a lot of work of face to optimise this appearance in the construction. All the efforts to save power and improve the efficiency have to be welcome”.

The aims of the plan are the improvement of the energetic efficiency of the envolvente edificatoria, the thermal sensors installations and of lighting of the park edificatorio existent; the improvement of the energetic efficiency of the commercial installations; the construction and integral rehabilitation of buildings with high energetic qualification and of consumption of power almost invalid.

In this plan there is, at least, two points in which the systems of refrigeration evaporativa could have “a crucial paper”: the efficiency in the thermal sensors installations of the buildings and the improvement of the energetic efficiency of the commercial installations.

The improvement of the thermal sensors installations of the edificaciones, for Lamúa, goes through to achieve the maximum efficiency regarding the consumption of power. In this appearance, the incorporation of the towers of cooling and condensers evaporativos in the systems of air conditioning used in the sector of the edificación, already treat of shopping centres or residential buildings, constitutes “an alternative to have very in account”, in the measure that guarantee the energetic saving, as well as the respect of the environingingment.

“In the plan throws in fault the quotation expresseses of the use of the systems of refrigeration evaporativa, since one of the elements that in greater measure influences in the consumption of power in any building is the system of conditioning employed, already treat of heating or of cold. The systems of refrigeration evaporativa already were included, by his high energetic efficiency, in the last PAE (Plan of Energetic Saving), of the Ministry of Industry”, aims the researcher.

The equipment that apply in his operation the principle of refrigeration evaporativa exert “a fundamental paper in the energetic saving”, constituting, by his operation and design, like “a real alternative” in any constructive action. The utilisation of towers of cooling and condensers evaporativos allows that the installations frigoríficas used in the conditioning of air are more efficient and, therefore, able to save power. Besides, these systems, adds Lamúa, allow the reduction of the pollution linked to his production and generate a lower dependency of sources limited.

According to data of the association, the towers of cooling and condensers evaporativos can arrive to represent for the productive system Spanish a saving in the consumption of electrical power of 25.000 annual euros by installation. Aefyt Has arrived to this conclusion after comparing the towers of refrigeration of water and condensers evaporativos with other alternative equipment and taking into account multiple factors, between them, the consumptions and environingingmental impacts of the production of electrical power in origin. “We estimate that, in the hypothetical case of the total disappearance of the towers of refrigeration, the increase of consumption of electrical power in Spain only would be asumible with the construction of three nuclear head offices of half type or seven thermal sensors head offices of cycle combined”, adds Lamúa.

So much by his application as by his design the equipment of cooling evaporativo save power. The lowest temperatures of cooling of water ensure an optimum operation of the installation frigorífica of the system of conditioning of air and reduce the consumption of power. “The equipment of cooling evaporativo are highly effective energetically because of the use of transfer of latent heat of evaporation”, sustains the researcher of the CSIC. This transfer allows the elimination of an upper quantity of heat to the attained with the use of a traditional transfer of sensitive heat, that is to say, requires a discharge of air until four lower times that the one who needs a process of cooling by air.

With this technology, the condensation in the installation frigorífica of the system of conditioning of air fits to realizar it to a suitable temperature so that the pressesure in the sector of high of the circuit refrigerator was very inferior and that, therefore, diminishes the risk of escapes of refrigerante and the consequent potential impact direct by atmospheric warming. On the other hand, when diminishing the temperature of condensation, the consumption of the necessary electrical power to do work a machine frigorífica, with identical provision that the condensed by air, can reduce of the 20 to 40%, and even more.

Besides, as it needs roughly a fourth part of air in comparison with a team of cooling by air, the consumption of power of motors of fans is very inferior.

“Results evident that when producing a lower consumption of power also is lower the effect invernadero indirect produced by the thermal sensors head office attendant to generate said power. In consequence, with these equipment achieves a lower cost by rights of broadcast of CO₂”, explains the technical adviser of Aefyt. It is necessary to take into account that 1 kWh of electrical power consumed pertinent of thermal sensors head offices can suppose, if it uses coal, near of 1 kg of CO₂ issued to the atmosphere. In the case of a head office of cycle combined produce 1 kWh would be 0,4 kg of CO₂ issued to the atmosphere. Finally, they produce fewer energetic losses in the transport of this lower necessary power from the head office generadora until the point of consumption.

The cooling evaporativo in Europe

The refrigeration by water constitutes a market in constant growth in Europe and in the world, so much regarding the number of installations —in the actuality exist in Europe more than 500.000 that use this type of equipment—, as regarding the number of supplying companies of the same. The use of the cooling evaporativo is backed by an important industry manufacturera, that chooses the cooling evaporativo in almost all the applications that have to dissipate heat and that has showed his worry in front of the restrictions imposed to these equipment and that put in danger the responsible industrial progress. In the actuality, in Europe exist more than thirty manufacturers with more than fifty plants of manufacture of these equipment that provide work to more than 7.000 employees and generate an annual half turnover above the 500 million euros.

The equipment of cooling evaporativo constitute a safe technology whenever, like sucede with all the technologies, fulfil with the preventive prescriptions and of control established by the valid legislation; what includes a suitable maintenance. Lamúa Defends his hygiene because so that it produce a shoot associated to a tower of refrigeration or team of cooling evaporativo is necessary that become a chain of events highly unlikely, that all they are related between himself and sucedan:

1. A colony virulenta of Legionella Prenmophila (LP) go in in the installation of the team of cooling of the tower (usually pertinent of the network of supply).

2. Uncontrolled conditions that favour the multiplication of the bacterium, circumstance highly unlikely in a team whose maintenance abide by the valid rule.

3. Download of a current of air bearer of a high percentage of drops in suspension containing a concentration of the bacterium with equal or upper levels to the threshold of considered infeccioso.

4. Inhalation, by part of susceptible human beings to suffer the illness (people inmunodeprimidas), of a sufficient number of drops, constitutive of the aerosols issued, to produce the illness.

Therefore, to warn of effective form the risk is sufficient to break the chain of above-mentioned events by any one of the links that integrate it. Three of them is possible to break them with a good design and a correct operation of the team.

1. Avoiding the conditions that favour the multiplication of bacteria with a correct cleaning and maintenance of the team, such as it prescribes the Law (RD 865/2003 of 4 July, by which establish the hygienic criteria-sanitary ware for the prevention of the legionelosis).

2. Minimising the drag of aerosols of water in the download of the air of the equipment with the available technologies.

3. Reducing the possibilities of inhalation of drops by the people by means of the suitable emplazamiento of the team.

The technical adviser of Aefyt puts like example the sector of the industrial refrigeration, that, as it ensures, few times has seen involved in episodes of shoots of legionelosis, since in general it has kept always properly his installations from the mechanical point of view (frequent cleaning, elimination of slimes, use of products desincrustantes, anticorrosivos, algicidas, etc.) with the end to preserve the thermal sensors efficiency of the equipment of transfer of existent heat in this type of installations and achieve like this keep in levels adapted the energetic efficiency of the same.

For the researcher results of “vital importance” treat the water of these equipment. The incrustaciones and the fault of cleaning reduce the performance of the system, increasing the costs of operation and favouring the microbial pollution. “The negative effects produced by 1 millimetre of incrustación in the battery of a tower with enclosed circuit supposes 30% of loss of transfer of heat, 6 °C of increase of the temperature of condensation and 18% more than consumption of the compressesion”, explains.

From the promulgation of the first Hygienic Regulation-Sanitary ware for the Control and Prevention of the Legionelosis, these installations are subjected, besides, to the maintenances and hygienic controls-sanitary ware foreseen in the quoted legislation garante of the hygiene of these equipment from the sanitary ware point of view. With his application breaks the link 2º and specifically with his article 7 forces to that they have of separadores of drops of high efficiency, so that, the discharge of water of drag was minor of 0,05% of the discharge circulante. If to this circumstance add the emplazamiento of these equipment in high and distant points concerning the zones in passing of the people, planted so that his download can not go in by the windows or by the takings of air of neighbouring buildings to the installation, the risk of inhalation of drops is practically non-existent.

Is, besides, highly likely that the scarce drops dragged evaporate when going in in contact with the air, no saturated, of the atmosphere and, in the case that they contained bacteria, these would have few possibilities to survive out of his necessary half hídrico.

“I would recommend that the election to install a tower of cooling (or team of cooling evaporativo) was a decision based in criteria strictly economic and environingingmental, exentos of prejudices and of an unfounded fear, assuming that the hygienic preventive maintenance sanitary ware, garante of the sanitary ware hygiene, will have to consider like an economic factor more”, ensures the technical adviser of Aefyt.

Regarding these equipment has improved his design, facilitating the access to his interior to realizar the works of preventive maintenance and control. In the last years has experienced a considerable technological advance destined, by a part, to improve the efficiency of the equipment and, by another, to reduce the risk that these can be transmissive of legionela. This is like this until the point that, at present, only a deficient maintenance is susceptible to generate this problem.

Between the technical advances that we can stand out find special fillings, filters of air of action combined against the rays UV, the dirt and the salpicaduras of water and the separadores or eliminadores of drops of high efficiency. “All they contribute of radical way to fulfil with the above-mentioned aims”, aims Lamúa. they are using New materials that allow treatment of disinfection and maintenance without deterioration of the equipment. The inner surfaces are smooth, the panels of removable closing to facilitate the cleaning of the filling. It has of systems advanced of physical treatments, fisicoquímicos and chemists of dosage and application in continuous, etc.

The Aefyt warned in the fair Air conditioning 2013 of the risk of replacement of the technology of the evaporation refrigerativa by other less efficient energetic and medioambientalmente owing to the persecution that suffer these equipment with reason of the legionela. In opinion of the researcher of the Ictan, the authorities would have to support and promote more the rational use of this technology, spreading his advantages and his hygiene by means of the preventive maintenance.

“Would have to, besides, exert an effective control of the fulfillment of the valid legislation”, aims. To dissipate fears and avoid social alarm, explains, would help a lot the transparency, that is to say, whenever it produced a shoot of legionelosis, the competent Administration would have to expose with clarity the results obtained in the performances of inspections realizar and include the precise information on the circumstances sobrevenidas in the team or equipment that had originated the shoot (type of equipment involved, degree of incumplimiento of the valid legislation of the same, etc.). “Like this the society would have of the necessary information to adopt responsible decisions in this matter”, sustains.

The refrigeration evaporativa is, definitely, “a technology of future” because of his high energetic efficiency and to his numerous applications, as it shows the push of the same in other countries of our surroundings, where apply legislations no restrictivas. On the other hand, the researcher remembers that the main aim of the association Aefyt is to do comprise to the society that, with a good maintenance, the towers of refrigeration are totally safe. “We would want that the authorities leave to take to these equipment like ‘heads of Turkish' in cases of legionela, that produce the maximum transparency when these produce and that support with a suitable legislation, no restrictiva, a fundamental technology for the industry”, concludes the researcher.