Solutions to the problems of low-temperature operation of air conditioners

Earlier we said that there are some problems when working air conditioners in heating mode at low temperatures. And, of course , if the manufacturers have not overcome them , conditioners and would continue to buy mostly just because of the cooling mode , only occasionally including their heating on in the offseason. Next, we will explain what the technical solutions have allowed to become full conditioners heating appliances .

1. Low-temperature startup. We have already said that at certain temperatures compressor oil ceases to be dissolved in the coolant , and the problem is easy to solve. The first way is to install on the bottom of the compressor crankcase heater that runs at low temperatures. In the crankcase will always be a mixture of refrigerant and oil , and will not be “cold” start compressor. This solution is not very energy-efficient and widely used only for non-inverter , the so-called start-stop (On-Off) air conditioners. This solution enables you to omit the lower bound start the air conditioner to a level -15 ° C. Basically this solution used Chinese manufacturers of climatic equipment . The fact that the prices of start-stop air conditioners are low enough and complete masters of the market economy class are Chinese . Just this solution widely used in OEM brands of air conditioners, which are widely available on our market and are produced by the same Chinese manufacturers. By the way, this solution is so simple that it can be implemented on virtually all models of air conditioners. Any mounting HVAC company in its proposals has so-called low-temperature kits for ” upgrade ” the air conditioner on low-temperature start. Major branded manufacturers focus on more energy efficient equipment – inverters .

Consider now the inverter air conditioner model (Inverter). This class of vehicles produced mainly by Japanese and American companies. The fact that the inverters are consumed , as in the cooling operation and heating operation by at least 30 % less energy than the non-inverter air conditioners. It’s quite technically complicated and expensive machinery . And of course for inverter air conditioners leading manufacturers invent more energy efficient solution , which allows for fast and low-cost electricity to raise the temperature in the crankcase . The fact that the inverter DC command processor can adjust the current which is supplied to the compressor windings . If a file compressor winding current is insufficient to run , the heat generated by the coils will raise the temperature in the crankcase , and start the compressor will not happen. Upon reaching a certain temperature, when the oil has already begun to be dissolved in the refrigerant , the processor delivers a current to the compressor of greater magnitude and executes it. For inverter air conditioners , depending on the settings in the different models , it was possible to omit the lower boundary to -15 ° C. .. -20 ° C, and in some samples to -25 ° C.

2 . Icing on the outdoor unit air conditioner. This problem as very dangerous and easily preventable. The fact that almost all models of air conditioners, which are designed for low temperature heating manufacturers are not equipped with protection against the formation of ice in the tray of the outdoor unit . Why is it we do not know . The author of this article at the time of publication known only two models of split-systems , which are now available on the market and are equipped with heating devices pallet at the factory : Mitsubishi Electric MSZ-FD VA / MUZ-FD VABH Zubadan and Toshiba SKVP2-EE Daiseikai Nordic. Naturally , when purchasing a point of sale in non-specialized , but simply in the supermarket, or in the “wild” mounting crew , or just have a firm with a low level of staff customer “forget” to mention the need to install the drain pan heating outdoor unit. Some manufacturers produce low-temperature optional kits for some models , some give this topic at the mercy of installers . However, buyers who expect to operate their air conditioning at low temperatures do not forget about the drain pan and heating if necessary to remind the seller of compulsory installation of this option .

3 . Performance drop with a drop in air temperature. As already stated above, all technical data that manufacturers publish in relation to heating mode , are at a temperature of the outside air +7 ° C. Adopted such a standard. However, the operating conditions are always far from the test . At temperatures in the street near -20 ° C performance of modern air conditioners falls roughly in half. And this is good data for inverter air conditioners from leading manufacturers. Chinese art for this parameter is even lower. Since in our country in winter is very often observed such low temperatures , you should pay attention to the parameters heating capacity ranging up to this temperature. Would also like to draw the attention of buyers to the fact that, as in any technique , in air conditioners is no magic and only apply the laws of physics . So here are the best indicators of those models for which the manufacturers have large heat exchangers, respectively, increased heat transfer area and the air conditioner is easier to pick up heat from the surrounding air. Therefore, when choosing conditioner refer to the rule: the bigger and heavier the outdoor unit – the better. Air conditioners with a small outdoor unit have low efficiency when working on heat at low temperatures. Incidentally this is also true for the air conditioner in cooling mode at extremely high outside temperatures .

Our story would not be complete without mention of us on quite a unique offer in the market that prevents performance degradation conditioner at low temperatures. The company currently produces Mitsubishi Electric air conditioners with unique technology ZubaDan ( translated from Japanese – super heating) . Without going into technical details , let’s say that the use of technology allows ZubaDan conditioners not lose its performance down to -15 ° C. At -20 ° C the performance of air conditioners Zubadan least twice the performance of everything that produces market. Due to high demand from European and American consumers split system Mitsubishi Electric Zubadan other manufacturers (Daikin / McQuay, Sanyo and Toshiba) are currently engaged in the development of proprietary technologies that allow air conditioners do not lose performance at low outdoor temperatures .


The first part of the article shows that the modern air conditioner is a great space heater , deprived of many of the shortcomings that were inherent in the previous generation model . Modern air conditioner is no longer seen by experts as a backup heat source . He is quite capable to become a major , and with proper selection, and the sole source of heat for space heating. The first part of the article was devoted exclusively to split- systems. In continuation we will talk about the application in the heating mode has a large class of equipment : multi-split systems , multi-zone air-conditioning and hot water systems . And of course tell you about this method of energy savings , as recovery . Watch for our announcements .

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