Sit and not sweat: seats for tankers with built-in air conditioning
Source: smolbattle.ru
As you know, in hot and sunny weather, being inside tank slightly reminiscent of going to the bath - the air temperature in its habitable compartments can reach +50 degrees Celsius. In such conditions, long-term combat work is out of the question, so the presence of air conditioners on military equipment has already become commonplace. But air cooling is just one of the ways to make the life of tankers more comfortable. An alternative could be a “cold seat”, developed back in the USSR in the 80s.
Source: ivan-perevodchik.ru
And why is it needed?
In order to understand the feasibility of developing a "cold seat", we need to talk a little about the requirements for tank air conditioners.
Why is it so hot in a tank? First of all, of course, because of the armor. The hull and turret of the tank heat up very quickly from the hot ambient air and sunlight, while they very actively give off heat and actually arrange a real bath from the habitable compartments of the tank. This harmful heating is supplemented by other sources of heat: a running engine and transmission, the heat from which penetrates into the combat compartment. Cannon firing also contributes - the calories of gunpowder burned when fired do not disappear without a trace.
Considering such a number of “heaters”, the air-cooling air conditioner must have a very decent power, therefore “eating” a couple of kilowatts from the tank’s on-board electrical network is far from the limit, and its possibilities are far from limitless. In addition, severe restrictions are imposed on the overall dimensions of the cooler, however, the largest elements of its design can be taken out of the reserved volume.
External air conditioning unit on the T-90CA tower.
Of course, today all these problems have been solved in one way or another, so the installation of a “Conder” is quite possible and is practiced, although not in a forced mass manner, for absolutely all cars. But what can a cool seat offer?
Very moderate power consumption. A conventional air conditioner needs to continuously distill large volumes of air through itself - hence, in general, those same kilowatts that load the on-board network. The seat cools the body of the tanker due to close contact with him. Thus, heat removal occurs directly, and this will certainly have a positive effect on the energy efficiency of the system - on average, one tanker seat required no more than 300 watts for its operation.
Well, it's time to consider this product in detail. Moreover, its composition is not limited to just one chair.
cool seat design
The product is based on a completely standard seat, the lower cushion (on which the tanker sits) was replaced with a modernized one. It has a panel consisting of nine thermoelectric elements operating on the principle of the Peltier effect.
In a simplified form, this effect consists in the transfer of energy (heat) during the passage of an electric current at the point of contact of two dissimilar conductors. An example is two elements - one from antimony and the other from bismuth. If a little water is dropped at the point of their contact and an electric current is passed through them, the water will turn into ice.
Source: V. A. Arefiev, V. I. Golub et al. “Local thermal protection of the VGM crew”.
During the operation of such thermoelectric panels, their upper part (plate), which is in contact with the tanker's body, will be cooled, while the lower one, on the contrary, will heat up. Therefore, water cooling is used to remove heat from these elements: water is driven through the heat exchangers of the cooling panels and then goes into a radiator blown by a fan.
Cooled seat and breathable vest. Source: V. A. Arefiev, V. I. Golub et al. “Local thermal protection of the VGM crew”.
But one "cold seat" decided not to do. An addition to it was a special anti-fragmentation tanker vest, to which an air blower is connected through a hose. This vest performs a dual role: it protects against injury when breaking through armor and cools the upper body of a person due to airflow.
As a result, although complex in appearance, it turned out to be quite energy-efficient installation, which during its operation consumed up to 80 watts in the blowing mode through the vest and up to 300 watts in the combined mode, when the body blowing and seat cooling were turned on simultaneously. Other characteristics can be seen in the attached image below.
Parameters of the cooled sitting complete with a vest. Source: V. A. Arefiev, V. I. Golub et al. “Local thermal protection of the VGM crew”.
Tests and conclusions
In order to test the performance and effectiveness of the cooling seat, they equipped the driver's seat in the T-62 tank and tested it in a desert area in southern Uzbekistan. For experimental races, the hottest daytime was chosen: from 12:00 to 18:00. At the same time, the air temperature inside the habitable compartments reached 48 degrees Celsius, and the internal surfaces of the tank - 55 degrees.
All crew members were dressed in the same clothes, consisting of cotton trousers and tunics, as well as vests and tarpaulin boots.
During the experiment, the fact was confirmed almost immediately: without an air conditioner in extreme heat, even just being in a tank without performing complex combat work is already torture. The commander and gunner, who did not have cooling seats, could not stand it for more than three hours. Moreover, there were often situations when the tests had to be interrupted within an hour or two after they began, because the tankers lost consciousness or were in such a state that the continuation of this execution threatened with serious consequences for their health.
Monitoring of the physiological parameters of the commander and gunner showed that their body temperature soared to 38,5-38,6 degrees Celsius, and the heart rate increased to 120 beats per minute. Moisture loss (through sweat) reached 850 grams per hour.
But the driver, as they say, was "high" with a blown vest and a cool seat. The high temperature inside the tank did not prevent him from driving the tank, by the way, doing a lot of physical work for six hours or more. In fact, he could sit in a heated car for at least a day if it was necessary.
His body temperature did not exceed 37 degrees, and his pulse was 76 beats. Moisture loss amounted to 708 grams. The result is quite excellent.
Also, in addition to the tank, the cooled seat was tested in the BMP-2 and BTR-80, where it also proved to be good. This can be found in the attached table.
Air conditioning, extractor - joint work of the seat and vest; hood - use only a blown vest; dash - no vest and cooling seat. Source: V. A. Arefiev, V. I. Golub et al. “Local thermal protection of the VGM crew”.
In general, the product turned out to be really interesting. It has become a rather non-standard solution for armored vehicles to the problem of normal climatic conditions in the habitable compartments of combat vehicles. At the same time, unlike classic air conditioners, this system consumed little power from the onboard electrical network - less than one kilowatt, if all crew members had cooled seats. Therefore, these coolers were actively proposed for installation on Soviet tanks, but it did not work out.
The prospects for such local thermal protection for tankers were very vague.
Firstly, for radiators and fans that cool the water, although not a large, but still very scarce free armor volume was required, each cubic centimeter of which in our tanks is already worth its weight in gold.
And secondly, given the conservatism of military (and not only military) officials, one could not even dream of installing even ordinary air conditioners, not to mention local ones.
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