The sleeping bag is the element that will allow us to spend a night in the mountain, either in a shelter or bivouac, causing our body temperature to stay within the proper limits to achieve a pleasant and restful sleep to continue our Activity the next day with sufficient strength.Next we will detail in technical way each one of the parts that compose a sleeping bag.
Before we continue, the first thing we need to know is how a sleeping bag works .The heat that is generated inside the sac is the very heat that we generate when we are inside.The only function of the sleeping bag is to maintain that heat and prevent its loss.Therefore, there are no “magic” bags that generate heat, or sacks that are hotter than others.
How does a sleeping bag get hot? According to pimasleepingbags, there are four phenomena that cause a sleeping bag to lose the heat of its interior and, therefore, decrease the temperature.These are evaporation, radiation, conduction and convection. Let’s see what each of them is.
- Evaporation : The moisture that transpires our body should go outside the sack as fast as possible, because by staying inside we would cool down reducing the temperature of the bag.
- Radiation : Any body radiates heat to the outside, especially the lower the external temperature;Hence the sack must provide some mechanism to prevent that heat from the sack can escape from it.
- Driving : Two bodies in contact pass heat until they are even.As the ground is at a lower temperature than we are, we would be constantly giving up the heat that we generate.Therefore, a good insulator is very important at bedtime on the floor.
- Convection : Hot air tends to escape and leave its place in cold air.Hence, the openings of the sac are another important point of heat loss inside, especially on windy nights, while on hot nights what you get is a pleasant freshness.
Now that we know the operation of the bag and what are the main problems to combat, we will proceed to detail each of the parts of which they are composed, analyzing what are their functions, advantages and disadvantages.
Filler material or insulation
It is a non-natural product with a very similar performance to down, normally made with polyester fiber.Its biggest advantage is the price and its fast drying time, that is, it works best in very humid environments.As inconvenience has its greater weight and worse compression.
Each manufacturer has its own synthetic fiber, with its technical name, here we do not want to analyze them all.There are many internet pages on which you can compare them once you know which are the ones that own the bag that you are looking at.