Anatomy of comfort

A modern country house is designed to be warm and cozy and should not depend on the vicissitudes of the weather. What kind of air fills it, is it cold for a person or, conversely, is it hot — it all depends on engineering systems specifically designed to provide comfort. That is from ventilation, heating and air conditioning. Let’s try to figure out what are the optimal settings for this equipment.

In the article «In the atmosphere of freshness» (N 6 for 2007d.) methods of ventilation and equipment for organizing air exchange were considered in detail. Today we will continue this conversation and talk about the values ​​​​of air exchange, temperature, humidity and air mobility recommended by scientists for a cottage.

Breath of spring

«PM Vent» Energy-saving ventilation system will provide the necessary air exchange in the premises of a country house withminimum costs. She works round the clockautomatic mode Prerequisite for comfort — Good ventilation in all rooms. It would be useful to recall that in unventilated rooms the content of carbon dioxide, as well as harmful substances emitted by furniture, plastics, carpets, wall panels, cleaning products and tobacco, often exceeds all permissible standards. This can cause constant fatigue, irritability, impaired concentration and headaches.

Exhaust room air, saturated with fumes and harmful substances, must be regularly replaced with fresh outdoor air (air purifiers will not help here). The minimum required volume of fresh supply air is calculated on the basis of the amount of carbon dioxide released by a person during breathing per unit time. This volume should be sufficient both to make up for the lack of oxygen, and to
Architect
I. Kholmogorov
A photo
V. Nefedova,
N. Karacheva removal from the house through the exhaust ventilation ducts of most household pollution.

ATresidential single-family buildings, according to SNiP 31-02— 2001, the minimum performance of the ventilation system in maintenance mode should be determined on the basis of at least a single exchange of air volume for 1h in premises of permanent residence of people. From the kitchen in this mode, you must remove at least 60m³/h of air from the bathroom and toilet — 25m³/h The air exchange rate in other rooms, as well as in all ventilated rooms in non-working mode, should be at least 0.2 room volume per hour. An increase in the amount of fresh air usually has a positive effect on a person’s condition.

Code of rules for the design and construction of engineering systems of single-apartment residential buildings (SP 31-106— 2002) recommends the design values ​​of air exchange for the premises of a country house in accordance with their purpose.

Thank you, and more!

The optimal condition for climatic comfort in the house can be considered such a balance of temperature, humidity and air mobility in the rooms, in which a person is able to do without the tension of thermoregulation mechanisms for a long time (increasing or weakening blood flow to the skin, changing the intensity of metabolism). With various combinations of these indicators in the premises, the thermal sensations of a person may turn out to be the same. However, these parameters — all together or separately — should not change arbitrarily, but only within certain certain limits that meet the conditions of comfort for all households.

The thermal sensations of a person in any of the rooms of a country house mainly depend on the air temperature and radiation temperature, which takes into account the intensity, magnitude and direction of radiation heat transfer between his body and the surfaces of walls, ceiling, floor and windows. With an increase in air temperature, the share of apparent heat removal from the human body decreases (as a result of convection and thermal conductivity), and as a result of evaporation, heat removal increases (a person begins to sweat). ATin case of excessive cooling of the air, instead of perspiration, chills appear due to hypothermia of the skin and respiratory tract. When the walls of the house are too cold, a person experiences extremely unpleasant sensations, even if the air temperature is comfortable: the house, as it were, draws vitality out of him. It is established that the temperature of walls and windows should be close to the air temperature in the premises. ATSNiP 31-02— 2001 «Single-apartment residential houses» states that the temperature difference between the internal air and the internal surface of the structures of the outer walls at the design temperature of the outdoor air should not exceed 4 C, and for the construction of the floor of the first floor — 2 C. The temperature of the inner surface of the structural elements of windows (binding, slopes, glass) should not be below 3 C (at the average outdoor temperature of the coldest five-day period of the year).

A little used in everyday life, but nevertheless a very informative indicator is convenient, the value of which allows you to fairly accurately predict the thermal sensations of most people in the room where it is measured, — resulting room temperature. It takes into account the radiation temperature (the temperature averaged over the area of ​​the internal surfaces of the room’s enclosures and heaters) and the air temperature in the room. To measure the resulting temperature when the air mobility in the room is less than 0.2m / s (at higher speeds, the indicator is calculated according to a certain formula) use special certified devices — ball thermometers (blackened copper ball with a diameter of 150mm). The temperature measured at their center — equilibrium due to radiative and convective heat transfer between the ball and the environment. To obtain reliable data, measurements must be made in accordance with the methodology set forth in GOST 30494— 96 Residential and public buildings. Indoor microclimate parameters.

In addition to temperature, relative humidity and air mobility have a huge impact on human thermal sensations. High humidity combined with high temperature impairs the heat exchange between a person and the environment, which leads to overheating of the body. This causes profuse sweating and fatigue; breathing becomes heavy, thirsty. At too low — less than 20-30% — moisture content (in winter, when the heating is on), the skin and mucous membranes dry out, the likelihood of diseases such as rhinitis, pharyngitis andt.n. No air movement or excessively low air velocities are associated with poor ventilation. At the same time, a thin immovable shell is formed around the human body, which is quickly saturated with water vapor, taking its temperature and reducing heat transfer. The moving air blows away the superheated air layer, saturated with water vapor, enveloping a person. But if the airflow is too intense and fleeting (more than 0.3m / s), heat losses increase significantly due to the convection heat exchange of the body with the environment. The increased air velocity is perceived as a draft.

At least 80% of the inhabitants of the planet feel the best if the so-called optimal parameters of the microclimate are maintained in the room. The microclimate is not so comfortable, but it is quite safe for health, the parameters of which do not go beyond the permissible limits. Limit values ​​for indicators of optimal and permissible temperature, relative humidity and air velocity are determined by scientists in relation to various premises of a country house, taking into account the time of year and are recorded in GOST 30494— 96.

It should be noted that the values ​​of the microclimate parameters presented in GOST in practice are unrealistic to provide in the volume of the entire room. For example, next to a working heater, the temperature will always be above the norm, and the air speed will go off scale at the undercuts of interior door panels. The normalization of climatic parameters was carried out in relation to a relatively stable volume, which is called the serviced area of ​​the premises (habitat area). This is a space bounded by planes parallel to the floor and walls: at a height of 0.1 and 2m above floor level (but not closer than 1m from the ceiling with ceiling heating), at a distance of 0.5m from the inner surfaces of the walls.

Recommended air exchange in the premises of a single-apartment country house

Optimal and permissible norms for temperature, relative humidity and air velocity in the serviced area of ​​residential buildings

• Source: Ideas for Your Home Magazine#115