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North Eastern Federal University

Abstract

The purpose of this work was to conduct experimental studies of the thermal insulation properties of products of “Sakhabult " (Russia) containing deer hair and compare them with similar products from other manufacturers. During the experiments, it was found that deer hair is a good heat insulator, this conclusion follows from a comparison with synthetic fibers, where it showed better results than the popular material sentipon, but slightly inferior to hollowfiber. Additionally, studies were conducted on the dynamics of temperature drop inside sleeping bags and various down jackets.

"Sakhabult" has been working on the market of fur and leather products for more than 20 years and is one of the largest production enterprises of Russian commodity producers. Natural furs of fur-bearing animals, deer, horses and cattle living in the Republic of Sakha (Yakutia) are widely used in products of our own production.

However, there are no comparative data on the thermal protection properties of the products of “Sakhabult " with products from other manufacturers. The purpose of this work was experimental research of thermal insulation properties of products "Sakhabult" containing deer hair and comparison with similar products from other manufacturers.

NETZSCH HFM 426 Lambda was used to measure the coefficient of thermal conductivity and thermal resistance, and the ИТП-МГ4.03Х heat flow meter was used to measure the heat flux density. A mannequin with temperature sensors was also made to monitor the temperature drop inside sleeping bags and outerwear [1].

To measure the heat flow, the test tissue sample was placed between two thermistors that measure the temperatures of the upper and lower surface of the sample.

A container with water heated to boiling (100° C) was placed on the upper surface of the sample, so the heat flow was generated due to the temperature difference between the lower and upper parts of the sample and was measured by a heat flow sensor, which was a thermal battery made of copper-constantane thermocouples. All sensors were connected to the heat flow meter ИТП-МГ4.03Х.

In the case of measuring soft materials such as down jackets, a 1 cm thick wooden block limiter was placed under the pan in order not to crush the layer of down stuffing, which causes thermal resistance that retains heat inside the down jackets.

FIG. 1. Dependence of the flow density on the temperature head of the product. The finished product Sakhabult(a), sleeping bags(b).

Figure 1 (a) shows the dependences of heat fluxes on the temperature pressure of various finished products of “Sakhabult” and sleeping bags. Studies were carried out with products of different thicknesses, so with identical fillers and materials, heat fluxes primarily depended on the thickness of the product. It can be seen that the minimum heat flow is observed in a thick seat stuffed with deer hair, and the greatest in a lint-free sunbed.

Figure 1 (b) shows experimental data comparing heat flows through the material of sleeping bags. As can be seen from the figure the best insulation performance was that of the nameless sleeping bag, the worst Mongolian camel sleeping bag, a little inferior to him in the insulation of sleeping bag products “Sakhabult”.

The nameless sleeping bag took a leading position not because the material and fillers had good thermal insulation qualities, but because of the thickness of the product itself, because in this case it is the finished product that is being studied and the thicker the material, the less heat it passes.

FIG. 2. Dependence of the heat flux density on the temperature head for the same thickness of the material (a) and the coefficient of thermal conductivity of the materials under study (b).

Studies of heat fluxes (Fig. 2 (a)) that pass materials showed that the best heat insulator is again hollowfiber- soft100, in second place is deer hair and the worst sintepon showed itself, which corresponds to the results obtained by measuring the thermal conductivity (Fig. 2 (b)).

The results of measuring the thermal conductivity coefficient of deer hair and comparing it with synthetic fibers and natural wool showed that deer hair has a lower thermal conductivity than sintepon and cotton wool, but more than hollowfiber-soft100. It follows that the best modern heat insulator is still a hollowfiber.

The table shows that the thermal resistance is the highest in natural cotton wool. The thermal resistance of deer hair is greater than that of synthetic fibers, but much less than that of natural wool.

To monitor the temperature inside the studied sleeping bags and down jackets, a mannequin with a length of 1.6 m and repeating the human constitution was made[1]. The mannequin was made of duct tape and stuffed with fabric.

At the characteristic points of the mannequin depicted, DHT22 temperature sensors were attached, which was connected to the computer via a USB port via the thermal sensor control board.

TABLE 1. Comparison of the coefficient of thermal conductivity and thermal resistance of deer hair with synthetic fibers and natural wool.

FIG. 3. Dynamics of temperature decrease inside the sleeping bag (a) and under jackets from different manufacturers (b)

Monitoring was performed on a personal computer using the Arduino Mega program. A dummy with sensors dressed in a down jacket or in a sleeping bag was placed in a freezer chest and cooled. As the mannequin cooled, the dynamics of temperature decrease under the jacket was recorded. The disadvantages of the method include the fact that the mannequin with clothes itself has a large heat capacity and this heat capacity is different depending on the jacket worn and introduces a disturbance to the temperature of the refrigerator.

The temperature of the dummy inside the sleeping bag was taken as the readings of the central sensor farthest from the edges of the sleeping bag and the points of contact with the cold surface of the freezer. The Fig. 3 (a) shows the dynamics of temperature decrease inside a sleeping bag manufactured by “Sakhabult”, and Fig. 3 (b) shows the results of a study of down jackets worn on a mannequin and placed in a freezer. As you can see from the graph, the best results were shown by Canada Goose down jackets, Expedition model and Bask Antarctica, and the worst performance was shown by the Alpha N-3b parka synthetic jacket. thermal insulation sakhabult deer outerwear

Conclusions

Deer hair is a good heat insulator, this conclusion follows from the results of experiments in comparison with synthetic fibers, where it showed better results than the popular material sintepon, but slightly inferior to hollowfiber. Additionally, studies were conducted to reduce the temperature inside sleeping bags and various down jackets.

References

1. К. Kuklane, V. Dejke Testing Sleeping Bags According to EN 13537:2002: Details That Make the Difference, International Journal of Occupational Safety and Ergonomics (JOSE) 2010, Vol. 16, No. 2, 199-216.

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