The Multi-zone Air-conditioning Systems – Trends of Development
In the beginning of 1970s the issue of the opportunity to use power efficient equipment in the buildings of big and average areas arose very sharply in front of the developers of air conditioning systems. At that time the most popular and traditional solution on objects, where a high refrigeration capacity was demanded, were refrigeration air-water systems in which cooled or heated water was circulating in the pipelines around the whole building and with the help of fan coil units cooled off or heated air in rooms.
It is well-known that to the share of climatic equipment falls a significant share of electric energy consumption, up to 50% from common power inputs of a building, that is why the problem of a high cost of maintenance has set a vector for creation of equipment with a different logic of work and management. The second prerequisite was a number of technical limitations for use of living and multi split-systems. That affected both a strictly fixed limit of lines which did not have to exceed 25 m and a small amount of internal blocks which were plugged to one external.
Thus, in 1982 the first in the world VRV (variable refrigerant volume) system appeared on the market. It significantly differed from predecessors with the fact that the integrated net of freon wires to which all internal blocks were input was used in it, while in traditional air-conditioning the input was made from the external block to the internal one (ones) individually. There are certainly a lot of differences from refrigerating machines, but the main is the lack of an intermediate heat-transfer agent, that significantly let overcome chillers at the rates of energy effectiveness. In spite of increase of the length of the lines and a higher manufacturability, the first models of multizonal air conditioners were close to the characteristics of modern multi split-systems and could serve no more than 16 internal blocks simultaneously.
In Russia VRV or VRF (variable refrigerant flow) systems could not find its place for a long time, and, on the one hand, usual “splits” were a real alternative, and, on the other hand, refrigerating machines, when a high refrigeration capacity was demanded. At that moment to buy several dozen split-systems and to mount them were much more profitable economically both at original outlays and at maintenance. The price also played some role while choosing chillers, their mounting and maintenance were cheaper in comparison with multi-zonal airconditioners. However, the problem was not only in price or mounting. Previous VRF generations, firstly, had significant limitations in the quantity of input internal blocks and length of lines; secondly, they had rather simple automation with a primitive functional in introspection and work analysis; thirdly, there were not almost any specialists of a required level who could qualitatively maintain VRF in Russia. It is logic to suppose that rather a high cost, a small number of plugged internal blocks, a small length of lines, and also low qualification of specialists were essential obstacles for a customer.
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The article prepared by the Technical department of LG Electronics company