Low Temperature

Cooling an object means extracting a certain amount of energy from it, imposing a more ordered structure. The first role of cold is, then, a stabilising, moderating action. Cold is used to limit r stop the Physical–chemical evolution of a system whose structure we wish to preserve. Biological products are the most unstable; water is responsible for this instability: all chemical reactions that take place in the body unfold in water solutions. This allows the solution of different chemical components, enzymes, serving as a reagent medium for the action of bacteria and fungi. To insure the preservation of a state of equilibrium within this living mass, we have to reduce the role of water until deactivated. Here is where cold intervenes.

The importance of artificial cold in today’s world is increasingly critical, mainly to insure the preservation of perishable goods by means of cold chains; generalised air conditioning; production in the food, cosmetics and pharmaceutical industry; and to preserve materials for biomedical and scientific research in general. The systems are often very sophisticated: the introduction of the marvels of electronic monitoring and computers now allowing previously unthinkable performance and consumption capabilities. Today the main problem is the Government’s responsibility regarding energy efficiency in these implementations, to reduce or contain the greenhouse effect and global warming. So there is another topic: attention to environmental impact. In the cold and low T industry, this is a particularly compelling topic. The debate on new fluids, the hole in the ozone layer, the greenhouse effect and international regulations are as current as ever. KW has always been sensitive to these issues, and since the end of 1994 it has provided CFC-free refrigerators and freezers.

Today, KW targets the following objectives: operate a valid selection of new refrigerants in installations; operate in the best manner to recover old refrigerants; aim at the optimisation of installations from an energy perspective and with a minimal amount of refrigerant; look for optimisation in terms of system regulations. In all applications, KW guarantees environmental protection with the use of substances with ODP (ozone depletion potential) = 0; a very low TEWI (total equivalent warming index) and GWP (global warming potential); and, above all, that are safe for workers, who handle non-explosive, non-toxic and non-flammable refrigerants.

KW, given its tradition and expansive industrial culture, operates in a broad temperature range: while the evaporation T can rise to +15 °C, its lower range extends to -130 °C (more if within the field of cryogenics). KW applications go from food processing and the pharmaceutical industry to the health care and biological laboratory sectors. In hospitals, refrigeration has assumed a crucial role determining the quality of patient care: we think about the storage of medications and chemical reagents for laboratory analyses, and the conservation of blood, plasma, serum and vaccines.

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KW systems are always managed by electronic digital controls that can be periodically calibrated, and include alarms for minimum and maximum T and power failures, functional alarms regarding condensation overpressure, etc. All this leads to minimal parameter fluctuations in time, which raises the reliability of the machinery and improves the quality of preservation. The end result is that the quality of the whole laboratory goes up.

Our biological refrigerators from +15 °C to +4 °C maintain different types of pharmacological and pharmaceutical products, including blood for transfusion centres.

KW refrigerators are always ventilated to achieve the maximum homogeneity in terms of T, to provide the same treatment to all stored samples. Refrigeration has the power to moderate the speed of chemical reactions, which increases at lower temperatures. It can help delay degenerative processes and insure temporary product conservation without altering its natural balance. But simply cooling is not enough to guarantee long-term preservation. This requires freezing, which causes the separation of water in the form of ice; the chemical system, deprived of its support, becomes inert. In this way a stabilising effect is obtained. Therefore, there is the possibility of preserving the morphologic structure and functionality of the cell, tissue or organ beyond the time limits imposed by Nature. Life is suspended, latent; it blocks, in a reversible fashion, all biochemical reactions that make up the cell’s metabolism.

From -20 °C to -50 °C plasma, diagnostic products, some sera and histological findings can be preserved. Temperatures of -80 °C are used to preserve materials for long periods, even years. This type of freezers needs a two-stage system due to thermodynamical issues, since the interval between the evaporation temperature (T), close to -90 ºC, and the condensation T, between +30 ºC and +40 ºC, is too broad according to different laboratory environmental conditions.

KW has invested a lot in the development of these systems, being the first in Europe to test R508B and being the first to promote evaporation trays in vertical freezers. It has also studied the completeness of the product offering: more solutions in terms of storage capacity, shape, accessories… in short, the customisation of your freezer. It has taken care of safety systems, and it is the only one in the sector that has developed the concept of biological bank, the safest and most complete solution for storage at -85 ºC, ideal when the materials being preserved have a very high intrinsic scientific value or when the quality of the laboratory activity must respond to the most stringent international standards: GMP, GLP, etc. Temperatures close to -130 °C are used for materials that have to be preserved for very long periods (even 10 years or more); and since conservation at such a low T guarantees the best preservation, since at this T all enzymatic activities are inhibited. This type of freezers needs exceptional thermal isolation and special three-stage systems with really specific refrigerants. Thus - today - KW prepares solutions that bring together good design and construction and a careful examination of environmental needs. Only this can result in elevated functional standards and low operation costs (power and maintenance).

Laboratories that intend to obtain certifications on operational quality issued by third-party accreditation entities need complex IQ (Installation Qualification) and OQ (Operational Qualification) operations; both KW and its users need to prepare specific protocols to support them.