The selection of the heater is carried out according to the power and operating conditions of the device. The topic of heaters is affected by the vapor content in the air - a parameter recommended for control. Low relative humidity of air is called the main cause of the disease in winter. Heating does not dry the air. How to choose a heater, so as not to sit in a puddle with relative humidity.
Relative Humidity and Heaters
I have heard about the choice of heater:
- When the heater is working, the air temperature rises, the relative humidity decreases. According to the formula for calculating the parameter, the vapor content in air( partial pressure) is divided into a saturated state: a fixed mass of moisture per cubic meter at a given temperature and humidity. With increasing temperature, the specific gravity of water increases.
As there was water in the air( for example, 7 grams per cubic meter), it will remain so. But the divider increases with increasing temperature - the relative humidity decreases. We recommend a simple experiment:
- Put a closed saucepan with water on a fire, gas burner, and a source of flame. Even in the rain. Check the contents after a couple of hours. Water will evaporate, even if outside 100% relative humidity. Inside - 0%.
In winter, the relative humidity of air outside is below 100%.Although the water vapor content required is much lower. So why think: heating the room, we get a different process than with the pan? The walls are heated, the moisture begins to evaporate at temperatures above zero. Nature tends to balance. Moisture on the walls cannot be taken from the street - it stretches from the room. Building material is permeable to water vapor, water tends to dryness.
Part of the molecules will go up through the ceiling, to the attic, to the next floor. The higher the energy of the particles, the easier it is to rise: the heated air masses move upwards. Water vapors rush up. Will go through the ventilation channels. But even in a sealed room or with fresh air ventilation, dry air will rush in from the gaps.
Soviet electric fireplaces were supplied with a tank above the spirals. Water poured inside. Capacity supplemented heater. If the temperature was set in the room - the need for additional moisture disappeared. Try using a hygrometer in your hands to heat the room at night, evaporating moisture. Remove the vessel, go to bed. In the morning, check: more comfortable indoors than in the evening. Moisture leaves the hot room, accumulates in the cold. The warm cellar will not be damp if there is an odorant; the moisture will gradually evaporate.
Relative humidity and heaters
Important! Reducing the relative humidity of the room below 35% dries the mucous membranes of the respiratory tract. The epithelium becomes easy prey of bacteria, which hovers in the air - winter epidemics come.
Heater selection. Relative air humidity is within 40 - 60%, recommended by doctors. Recalling the above calculations:
- If you put a heater - we will consider humidity control, measures to adjust the parameter. Buy a decorative wall hygrometer, find another sensor.
It is easy to dry the air - it makes a domestic heater when working. The reverse process is shown above. To keep the humidity the same, we find the tables for calculating the parameter. The partial pressure( weight in grams) of vapor for saturated air under normal conditions is given. Dependence is built on temperature:
- At a temperature of 17 ºС and 100% relative humidity, the vapor content is 14.5 grams per cubic meter.
- At a temperature of 20 ºС and 100% relative humidity, the vapor content is 17.3 grams per cubic meter.
To begin with, we measure the room, find the volume of the room( excluding furniture), using the formula, multiplying the sides by the height. Let's say it turned out 25 cubic meters. Let the humidity 40%, we want to keep the level. Consider:
- Vapor content at the starting point: 0.4 x 14.5 x 25 = 145 grams.
- After heating will be: 0.4 x 17.3 x 25 = 173.
- It is necessary to evaporate 28 grams of water. Put a mug on the battery and get the desired result.
Excluding fresh airflow with lower humidity. For a value of 60%, we obtain the following calculations: 259.5 - 217.5 = 42 grams - more. When the volume of the room is 25 cubic meters, any humidity not exceeding the norm, it is enough to evaporate the arithmetic average without taking into account the loss of fresh air to the relative humidity tends to 50%.It will be 35 grams of water. Similarly, to account for the ventilation subsystem, it is necessary to know how many cubic meters pass through the ventilation channel in an hour. We take the fractional ratio of the volume of the room to the apartment - we get the desired value. Measure flow is not easy: you need a special device anemometer.
For rough calculations, we recommend to consider: the air is updated in the apartment 2 - 3 times per hour.
Ideal: there is a psychrometer in the apartment, you can experimentally determine the need. At night it is required from half a liter of water, you can not ignore the evaporation emanating from people, the value is significant during exercise. Proper selection of a heater for an apartment is not the only necessary step. Required to withstand the right climatic conditions in the premises.
Considered: oil heaters dry the air more than others. They have a high temperature - to concentrate the ascending flow. The role played by two factors: fire safety, heat transfer rate. To solve the problem, oil heaters with a chimney effect are produced: it will allow to organize movement, increase heat transfer, and reduce the temperature. Higher temperatures cause an evaporation effect. Local heating of water vapor leads to the excess flow through the walls and ceiling in an intensive manner.
If the blower, the convector quickly blows the air out - by measuring the temperature of the input stream, they respond more quickly to the modes - they are turned off. The oil heater works longer than necessary, gives more power, overheats the room: the air is dried by the methods described stronger. The main reason - given more energy. If we consider the infrared heaters - units are able to heat the room sectors. With the maintenance of normal conditions in the locations of people, it is possible to give less energy - the drying of the air is not intensive.
In practice, the dependencies of draining the premises are drawn - viewed in the building codes. Before choosing a heater for an apartment, evaluate the result brought by switching on the device. Remember: engineering estimates sin an error up to 30%.Difficult - test theory with practice before buying an infrared heater.
According to the recommendations of the doctors, the room temperature should be between 18 and 22 degrees Celsius - relative humidity depends.