Optimum residential heating system. Overview of heating systems for residential and administrative buildings: examples of calculation, regulatory documents. Category of work according to the level of energy consumption, W

According to hygiene requirements Living spaces:

- must be sufficiently spacious, dry, bright, clean;

Reliably protect from cold, rain, wind, heat;

- have favorable microclimate;

- be beautifully designed architecturally and aesthetically;

- provide silence, peace, comfort, rest;

- provide necessary conditions for work.

Hygiene requirements to living quarters:

1. parameters of apartments (size of living space per person, height of premises, utility rooms);

2. optimal microclimatic parameters, taking into account the season of the year and climatic regions;

3. requirements for the air environment, including heating and ventilation systems;

4. requirements for natural and artificial lighting, including indoor insolation;

5. permissible parameters of the physical factors of the environment (noise, vibration, ultrasound, infrasound, electric and electromagnetic fields, etc.);

6. requirements for building materials and interior decoration residential premises.

The main element of the home is flat(living cell).

Internal layout apartments should provide favorable conditions for life:

Sufficient soundproofing rooms;

Sufficient insolation rooms;

Possibility through ventilation rooms.

Apartment layouts can be unilateral and bilateral, the latter is the most favorable from a hygienic point of view, when the premises are located both on the side of the facade of the building and in the courtyard.

Depending on the functional purpose apartments are divided into residential(bedrooms, hall, office) and ancillary(hall, kitchen, bathroom, toilet, pantry).

Bedrooms and office should be isolated, common room- the hall can be a walk-through.

Ø Minimum living area set for one person at least 9 m2.

Ø Minimum kitchen area should be not less than 8 m2, it must be insulated to allow satisfactory air exchange.

Ø Bathroom and toilet designed separately, but one-room apartments combined bathrooms are allowed.

HOUSING MICROCLIMATE

The microclimate of the dwelling big influence on the body. The most important factor in the microclimate of dwellings is air temperature.

in winteroptimal room temperature:

Ø for cold belt is 21 – 22 C, (for example, S. - Petersburg),

Ø for temperate zone 18 - 20 C, (for example, Bryansk, Moscow)

Ø for warm and hot 17 - 18 C.

For a normal warmth sensation, it is important relative humidity, the optimal value of which should be 40 – 60 %.

The amount of heat transfer is influenced by air speed.

For comfort winter air velocity must not exceed 0.3 m/s. At high speeds air movement creates a feeling of draft.

HEATING

Heating creates a favorable microclimate in the winter in residential and public buildings.

Heating must meet the following hygiene requirements:

Maintain a certain level of indoor air temperature;

Ensure uniformity horizontally and vertically;

The temperature of heating devices should not exceed 90º C;

It should not serve as a source of indoor air pollution with smoke, soot;

There are two types of heating: centralized and local heating.

Ø local heating - in which the heat source and the heating device in the water structure in the heated room.

Local heating is furnace and gas heating.

Ø Central heating – the heat source is arranged separately from the heating devices, where it is located in the room.

Distinguish: steam, water, panel and air, depending on the coolant used .

Ø Steam - the coolant is steam, which is supplied under pressure to the room.

Disadvantages of steam heating:

Inability to regulate heat supply.

High temperature on the surface of the radiators (dust burning).

It is used for heating clubs, warehouses, industrial enterprises, theatres.

Ø Water– one of the best is water heating low pressure . Coolant - hot water. Provides uniform heating of air, tk. the temperature of the radiator surface does not rise by more than 80 - 85 C.

It is used for heating hospitals, residential and public buildings. AT rural environment apply apartment systems water heating.

Ø Panel (radiant) heating – the source of heat is walls, ceilings, floors, in which radiators with circulating hot water are laid.

The most favorable heat sensation is observed when heated:

Wall panels up to 40 - 45º С,

Ceiling 28 -30º C,

Floor 25 - 27ºС.

This system provides a state of comfort at a lower air temperature and less heat loss by radiation. Currently, CHP is used for heating, which makes it possible to arrange hot water supply in houses for domestic purposes.

Ø air heating – the heat carrier is air. For this outside air is sucked in by a fan, filtered, heated in heaters, humidified, and through a network of intra-wall channels enters the upper zone of heated rooms. holes exhaust channels located at a height of 30-40 cm from the floor. It is used for heating industrial premises.

VENTILATION

To create an optimal indoor air environment, use ventilation– is the replacement of polluted air with cleaner outdoor air..

Ventilation volume called the amount of air (in cubic meters) that should enter the room for each person per hour.

The amount of ventilation should be not less than 35 - 37 m3 / hour per person.

Air exchange rate – This is the number of times the indoor air has been replaced by outdoor air in an hour..

Distinguishnaturalandartificialventilation.

Ø natural ventilation – it's an exchange room air to the outside through the windows, transoms, ventilation ducts, which is carried out under the influence of the temperature difference between the outdoor and indoor air, as well as due to the pressure difference.

Most Effective through ventilation. The air exchange takes place during 3 – 5 min.

Ø artificial ventilation it happens local(for a specific room, place) or central(for the whole building).

Mechanical ventilation can be: supply, exhaust, supply and exhaust(combined).

- Supply - clean atmospheric air is supplied, and polluted air is removed through vents and transoms(hospitals, theatres, etc.).

- exhaust– polluted air is removed, and clean air is supplied through windows, cracks.

- Supply and exhaust - an equal supply and exhaust is established, or the predominance of one or the other. The hood should prevail over the duct in the premises, the air from which should enter the adjacent room (kitchen, toilet, pantries). In a room where air purity is given special meaning(operating room), the air supply must prevail over the exhaust. In this case, the inflow is carried out in the upper zone of the premises, and the extract from the lower zone.

The most improved type of artificial ventilation is air conditioning. This creates the necessary microclimatic conditions. Air conditioners can be used to clean the air from dust, ozonize and deodorize it. Used in residential and public buildings, airplanes, healthcare facilities, kindergartens.

Creation effective system heating of large buildings differs significantly from similar autonomous schemes of cottages. The difference lies in the complexity of the distribution and control of the coolant parameters. Therefore, you should take a responsible approach to the choice of the heating system for buildings: types, types, calculations, surveys. All these nuances are taken into account at the design stage of the structure.

Requirements for heating residential and administrative buildings

It should be immediately noted that the heating project for the administrative building must be carried out by the relevant bureau. Specialists evaluate the parameters of the future building and, in accordance with the requirements of regulatory documents, choose the optimal heat supply scheme.

Regardless of the chosen types of heating systems for buildings, they are subject to stringent requirements. They are based on ensuring the safety of the functioning of heat supply, as well as the efficiency of the system:

• Sanitary and hygienic. These include uniform temperature distribution in all areas of the house. To do this, pre-calculation of heat for heating the building;
• Construction. The operation of heating appliances should not be impaired due to the peculiarities structural elements buildings both inside and outside it;
• Mounting. When choosing technological schemes of the installation, it is recommended to choose unified units that can be quickly replaced with similar ones in case of failure;
• Operational. Maximum automation of heat supply operation. This is the primary task along with the heat engineering calculation of the heating of the building.

In practice, proven design schemes are used, the choice of which depends on the type of heating. This is the determining factor for all subsequent stages of work on arranging the heating of an administrative or residential building.

When commissioning a new house, tenants have the right to demand copies of all technical documentation, including the heating system.

Types of building heating systems

How to choose the right type of heat supply for a building? First of all, the type of energy carrier is taken into account. Based on this, you can plan the next stages of design.

There are certain types of building heating systems that differ in both the principle of operation and operational qualities. The most common is water heating, as it has unique qualities and can be adapted relatively easily to any type of building. Having calculated the amount of heat for heating a building, you can select the following types of heat supply:

• Autonomous water. It is characterized by high inertia of air heating. However, along with this is the most popular type building heating systems due to the wide variety of components and low maintenance costs;
• Central water. In this case, water is optimal type coolant for its transportation over long distances - from the boiler house to consumers;
• Air. Recently, it has been used as common system climate control in homes. It is one of the most expensive, which affects the inspection of the heating system of the building;
• Electrical. Despite the low cost of the initial purchase of equipment, electric heating is the most expensive to maintain. If it is installed, it is necessary to calculate the heating according to the volume of the building as accurately as possible in order to reduce the planned costs.

What is recommended to choose as a heat supply for a house - electric, water or air heating? First of all, you need to calculate the thermal energy for heating the building and other types of design work. Based on the data obtained, the optimal heating scheme is selected.

For a private house The best way heat supply - installation gas equipment in conjunction with a water heating system.

Types of heat supply calculation for buildings

At the first stage, it is necessary to calculate the thermal energy for heating the building. The essence of these calculations is to determine the heat loss of the house, the selection of equipment power and thermal regime heating work.

To correctly perform these calculations, you should know the parameters of the building, take into account climatic features region. Before the advent of specialized software systems, all calculations of the amount of heat for heating a building were performed manually. In this case, there was a high probability of error. Now, applying modern methods calculations, you can get the following characteristics for drawing up a heating project for an administrative building:

• Optimum load on heat supply depending on external factors- outdoor temperature and the required degree of air heating in each room of the house;
• Proper selection of components for heating equipment, minimizing the cost of its purchase;
• Possibility to upgrade the heating system in the future. Reconstruction of the heating system of the building is carried out only after the agreement of the old and new schemes.

When making a heating project for an administrative or residential building, you need to be guided by a certain calculation algorithm.

The characteristics of the heat supply system must comply with current regulations. Their list can be obtained from the state architectural organization.

Calculation of heat losses of buildings

The determining indicator of the heating system is the optimal amount of energy produced. It is also determined by the heat losses in the building. Those. in fact, the work of heat supply is designed to compensate for this phenomenon and maintain the temperature at a comfortable level.

For the correct calculation of heat for heating the building, it is necessary to know the material of manufacture of the outer walls. It is through them that most of the losses occur. The main characteristic is the coefficient of thermal conductivity of building materials - the amount of energy passing through 1 m² of the wall.

The technology for calculating thermal energy for heating a building consists of the following steps:

1. Determination of the material of manufacture and the coefficient of thermal conductivity.
2. Knowing the wall thickness, the heat transfer resistance can be calculated. This is the reciprocal of thermal conductivity.
3. Then several heating modes are selected. This is the difference between the temperature in the supply and return pipes.
4. Dividing the resulting value by the heat transfer resistance, we get heat loss per 1 m² of wall.

For such a technique, you need to know that the wall consists not only of bricks or reinforced concrete blocks. When calculating the power of the heating boiler and the heat loss of the building, thermal insulation and other materials must be taken into account. The total coefficient of TV transmission resistance of the wall should not be less than the normalized one.

Only after that you can start calculating the power of heating devices.

It is recommended to add a correction factor of 1.1 to all the data obtained for calculating the heating by volume of the building.

Calculation of the power of equipment for heating buildings

To calculate the optimal heat supply capacity, you should first decide on its type. Most often, difficulties arise in the calculation of water heating. For the correct calculation of the power of the heating boiler and heat losses in the house, not only its area, but also its volume is taken into account.

The simplest option is to accept the ratio that 41 W of energy is required to heat 1 m³ of a room. However, such a calculation of the amount of heat for heating the building will not be entirely correct. It does not take into account heat losses, as well as climatic features of a particular region. Therefore, it is best to use the method described above.

To calculate the heat supply according to the volume of the building, it is important to know the rated power of the boiler. To do this, you need to know the following formula:

Where W– boiler power, S- area of ​​the house To- correction factor.

The latter is a reference value and depends on the region of residence. Data about it can be taken from the table.

This technology allows you to perform an accurate thermal calculation of the heating of the building. At the same time, the heat supply capacity is checked against heat losses in the building. In addition, the purpose of the premises is taken into account. For living rooms, the temperature level should be between +18°C and +22°C. The minimum level of heating of sites and household rooms is +16°С.

The choice of heating mode is practically independent of these parameters. It will determine the future load on the system depending on weather conditions. For apartment buildings calculation of thermal energy for heating is done taking into account all the nuances and in accordance with regulatory technology. In autonomous heat supply, such actions do not need to be performed. It is important that the total thermal energy compensated for all heat losses in the house.

To reduce the cost of heating system recommended when calculating the volume of the building to use low temperature regime. But then you have to increase total area radiators to increase heat output.

Maintenance of the building heating system

After the correct heat engineering calculation of the heat supply of the building, it is necessary to know the mandatory list of regulatory documents for its maintenance. You need to know this in order to timely control the operation of the system, as well as to minimize the occurrence of emergencies.

Drawing up an act of inspection of the heating system of the building takes place only by representatives of the responsible company. This takes into account the specifics of heat supply, its type and Current state. During the inspection of the heating system of the building, the following items of the document must be filled out:

1. Location of the house, its exact address.
2. Link to the contract for the supply of heat.
3. The number and location of heat supply devices - radiators and batteries.
4. Temperature measurement in rooms.
5. Coefficient of load change depending on current weather conditions.

To initiate an inspection of the heating system at home, you must submit an application to the management company. It must indicate the reason - poor performance of heat supply, emergency situation or non-compliance of the current system parameters with the norms.

According to current regulations, during an accident, representatives of the management company must eliminate its consequences within a maximum of 6 hours. Also after that, a document is drawn up on the damage caused to the owners of the apartments due to the accident. If the reason is an unsatisfactory condition, the management company must restore the apartments at its own expense or pay compensation.

Often, during the reconstruction of the heating system of a building, it is necessary to replace some of its elements with more modern ones. Costs are determined by the fact - on whose balance sheet heating system. Restoration of pipelines and other components that are not located in the apartments should be handled by the management company.

If the owner of the premises wanted to change the old cast iron batteries for modern ones, the following actions should be taken:

1. AT management company a statement is drawn up, which indicates the plan of the apartment and the characteristics of future heating devices.
2. After 6 days, the Criminal Code is obliged to provide technical specifications.
3. According to them, the selection of equipment is carried out.
4. Installation is carried out at the expense of the owner of the apartment. But at the same time, representatives of the Criminal Code must be present.

For autonomous heat supply of a private house, nothing needs to be done. Responsibilities for arranging and maintaining heating at the proper level belong entirely to the owner of the house. Exceptions are technical projects for electrical and gas heating premises. For them, it is necessary to obtain the consent of the Criminal Code, as well as select and install equipment in accordance with the terms of reference.

The video tells about the features of radiator heating:

Microclimate of buildings- is a set of meteorological conditions in the room, evaluated by temperature, mobility and relative humidity air and the radiation regime of the premises, determined by the temperature of the enclosing surfaces.

Optimal air temperature in a cold climate is 20-23 o C, moderate - 20-22 o C and hot - 23-25 ​​o C. The temperature gradient along the height of the room should not exceed 2 o C. If it is more than 3 o C, then the limbs are cooled and a reflex change in the temperature of the upper respiratory tract. The temperature of the inner surfaces of the walls should not be lower than 2-3 o C of the air temperature of the apartment.

Air mobility - an important microclimatic indicator, since moving air has a dual effect on the human body: purely physical and physiological; norm - 0.1 - 0.25 m / s. A slight movement of air excites complex reflex processes of thermoregulation: when it is cold + excessive mobility, heat loss through convection and evaporation increases, the body quickly becomes supercooled.

Humidity air affects the heat loss of the body, causing an overstrain of adaptive capabilities; the optimum relative humidity is 30 - 60%.

Natural lighting. The light factor has a high biological significance, plays a primary role in the regulation of the most important functions of the body. Insolation - direct illumination sunlight; the norm for residential buildings is 3 hours / day. Under the influence of light in the body, gas exchange decreases, protein metabolism increases, and mineral metabolism normalizes. Under the influence of UV rays, biologically active substances and vitamin D are formed, which strengthens the skeleton of the body. The sun's rays are bactericidal: they kill microorganisms - they disinfect the room, reduce dampness, preventing the development of mold.

Daylight indoors is created by direct, diffused and reflected sunlight. It can be side, top, combined. Room lighting depends on orientation premises - the location of the windows of the building according to the cardinal points. The optimal orientation of windows in a temperate climate of residential buildings is South-West and South-East, in schools - East. Level natural light is evaluated using relative indicators - KEO and SC.

KEO (natural light factor) reflects the ratio of the illumination inside the room to the simultaneously measured illumination from the outside, measured in%. The norm is at least 0.5-0.7%. There are 2 methods for determining KEO: instrumental and calculated.

SC (light coefficient) - the ratio of the window glazing area to the floor area - in the form of a fraction, where the numerator is "1", and the denominator is a number showing what part of the floor area is occupied by the glazed surface of the frames; the norm is 1/6-1/8.

Note:Natural lighting in residential buildings depends on a number of factors:

1) window orientation according to the cardinal points: from a hygienic point of view, orientation to the South and South-East is advisable. Northwest. The western location of residential premises is not recommended: significant radiation in summer and negligible in winter;

2) window size and location: the location of the window closer to the ceiling contributes to more deep penetration Sveta. The width of the walls should not exceed one and a half width window openings. It is better rectangular windows;

3) depth of the room distance from a wall with a window to another wall. It shouldn't. exceed the distance from the upper edge of the window to the floor by more than 2 times .;

4) gap between neighboring buildings must be at least twice the height of the opposite building;

5) glass quality and degree of purity: clean glass already absorbs UV rays, while contaminated glass also absorbs light - up to 25-50%, curtains - up to 40% of light;

6) the nature of the color of the walls and ceiling: bright hues reflect light, increasing illumination.

Artificial lighting. The lack of natural light is compensated by artificial sources: incandescent or fluorescent lamps. In incandescent lamps, only 7-12% of the energy consumed is converted into light energy, the rest into heat. Requirements for artificial lighting: 1) sufficiency for a certain type of work; 2) uniform in space; 3) without glitter and 4) shadows.

Illumination standards are set depending on: the conditions of visual work, the lighting system and the type of lamp. Illumination standards in living rooms - 75 lux; in the kitchen - 100 lux, while reading - 300 lux.

For quality assessment artificial lighting exist additional indicators :

a) an indicator of discomfort, evaluating the brilliance; b) the pulsation coefficient of illumination; and c) the glare index, expressed in relation to the illumination of the visible part of the dwelling with shielding to the visible part without shielding (with glare).

Fluorescent lamps are more economical with the same energy consumption, have a higher luminous efficiency, their emission spectrum approaches the spectrum daylight, creates a soft diffused light, does not give shadows, does not require lampshades. But it has a pulsation and below 75 lux there is a “twilight effect”, which is subjectively assessed as insufficient illumination, therefore, with these lamps, a large illumination norm is set.

Heating residential and public buildings must maintain a certain level of T 0 indoor air, ensure its uniformity horizontally and vertically. Heating appliances should not degrade indoor air quality. Heat is transferred from a hotter body to a colder one using three methods: convection, radiation and conduction,

Convection is the transfer of heat through air. Radiation is the emission of heat rays. Conduction is the transfer of heat from a heated surface to a colder one through contact. From a hygienic point of view, radiant heat (internal, fireplaces) is more favorable.

There are centralized and local types of heating. centralized heating (water, steam, panel, air) has advantages over local heating: it maintains a constant air temperature and does not pollute it. At steam heating coolant - steam; its disadvantage is the inability to regulate the supply of heat, heat radiators (more than 90 0) - dust burns, and soot settles on the walls. More common for heating residential and hospital buildings water heating low pressure - hot water coolant; advantage: you can adjust the degree of heating of the batteries, the purity of the air. Most hygienic panel or radiation heating - intra-wall when pipes with hot water pass through the walls. The most favorable heating of the walls is 40-45 0 , the ceiling is 28-30 0 , the floor is 25-27 0 , i.e. comfort is provided with more low temperatures and less heat loss by radiation, the cooling of the room during ventilation decreases. In addition, during the hot season, panel heating can be used to cool the room.

Local heating is stove, electric, gas and is carried out using furnaces of greater or lesser heat capacity. Furnaces with large heat capacity include Dutch and other thick-walled brick stoves. They warm up slowly, but also cool down for a long time, maintain the air temperature at the right level. Small-capacity stoves are used for temporary residences (dachas) - they heat up quickly and cool down quickly, smoke and pollute the air with dust.

Ventilation. As a result of human activity, the air in residential and public buildings only changes for the worse (!), in particular:

1) air temperature and humidity increase: a person emits 40-80 g / hour of moisture;

2) the concentration of oxygen in the air decreases - from 21 to 16% and the assimilation of oxygen worsens as a result of a decrease in negative air ions in the air;

3) the concentration of carbon dioxide increases - from 0.04 to 4%;

4) as a result of the decomposition of dust and sweat in the air, bad smell;

5) along with dust, microbes and viruses enter the air, which can cause SARS, measles, scarlet fever, tuberculosis; as well as mold spores, products of processing by mites of fluff, wool, hair, skin flakes, which can cause allergic manifestations;

6) in apartments with gas stoves, the content of carbon dioxide is increased + unburned gas + soot + drops of fat in the air;

7) stand out from the walls and basements - radon;

8) phenol is released from carpets and furniture made of pressed shavings.

So stay on fresh air is always better for the body than in an apartment

Basic hygiene requirements for ventilation devices apartments: (1) must provide and maintain, in conjunction with heating systems comfortable temperature and humidity; (2) to carry out full circulation of air in the room; (3) prevent accumulation foreign odors; (4) be small in size; and (5) be silent.

Ventilation is characterized air exchange rate is a number showing how many times the indoor air has been replaced by outdoor air in an hour. The amount of air that needs to be supplied to the room per unit of time depends on: the cubic capacity of the room, the number of people, the nature of the work performed and the amount of harmful substances in the room air. In accordance with sanitary requirements should be in residential buildings. ensured removal of 3 m 3 within 1 hour per 1 m 2 of the room, and from the kitchen with gas stove- not less than 9 m 3. According to the method of supplying air to the room, natural and artificial (mechanical), local and general ventilation are distinguished.

Natural ventilation is the exchange of air through the pores of building materials, leaky walls, ventilation ducts and vents, which is carried out due to the temperature difference between the outside and inside air and the pressure difference. Through pores in building materials and cracks in windows, 1-fold air exchange is provided for 1 hour. From a hygienic point of view, transoms that open at an angle of 45 degrees to the window surface are most appropriate, which contributes to air preheating + no draft + less noise from the street. But the best ventilation is through: in 3-5 minutes. the air in the room is completely replaced by outside air.

If natural exhaust is ineffective, they arrange an additional effective, but incentive - artificial. She may be local- from the stove and central- for the entire building. Unlike the natural one, it depends on the room T o, the pressure of the outside air, it acts constantly and evenly. Central ventilation is supply and exhaust. At inlet in. fresh air served, and contaminated squeezed out through doors and windows (used in public buildings: theaters and hospitals (operating rooms). Exhaust ventilation - removal of air from the room, and the inflow is not organized - it is carried out through cracks, pores, windows; organized in the form of a local extract - over the place of harmful secretions. There is equal supply and exhaust ventilation or the predominance of something. So in toilets and kitchens, where the smell should not enter the rooms, the hood predominates.

The most advanced type of artificial ventilation - conditioning air, when air is supplied with the necessary microclimatic parameters (temperature, humidity, speed) + is cleaned of dust + ozonized + charged with air ions + deodorized. In everyday life, simpler ionizers and air purifiers are used.

In rooms where a person rests or works, microclimatic conditions should ensure good thermal well-being and the normal course of physiological processes.

The perfection of thermoregulatory mechanisms allows a person to maintain thermal balance and adapt to various temperature conditions. environment. However, the possibilities of thermoregulation are not unlimited. Prolonged exposure of the human body to unfavorable meteorological conditions disrupts thermal equilibrium and poses a health hazard.

It has been established that for a person dressed in light clothing and at rest, the most favorable air temperature is 18-20°C with a relative humidity of 30-60% and an air velocity of 0.2 m/sec. Depending on the season and individual features of a person, these boundaries can shift somewhat in one direction or another. At the same time, it is very important that the air temperature in the room be uniform both in the horizontal and vertical directions (from windows to the opposite wall, temperature fluctuations should not exceed 2 °, and from floor to ceiling - 3 °). It is also necessary that the air temperature be uniform throughout the day and that the difference between the temperatures inner surface walls and the air temperature in the room was no more than 5 °. All these temperature conditions can provide rational heating, to which, in addition, the following hygienic requirements are imposed: 1) the surface temperature of the heating devices should not exceed 85 °, otherwise the settled dust will burn, accompanied by the release of gaseous products that irritate the mucous membranes and have an unpleasant odor; 2) heating should exclude the possibility of air pollution by smoke, soot, ash, coal dust and harmful gases (carbon monoxide, carbon dioxide, sulfur dioxide); 3) the heating system must be silent, safe in terms of fire, cheap, easy to maintain and maintain, providing the ability to control the heat transfer from the surface of the heating devices.

Of great hygienic importance is the type of fuel used for space heating, since combustion different varieties fuel causes pollution to a greater or lesser extent atmospheric air and indoor air. Yes, burning solid fuel(firewood, coal, peat, shale) atmospheric air is polluted with ash, smoke, carbon monoxide (with incomplete combustion), sulfur dioxide (with a high content of sulfur in the fuel). Liquid grades of fuel (fuel oil, etc.) produce a lot of soot during combustion. From a hygienic point of view, the most appropriate is gaseous fuel(natural and artificial lighting gas), however, with the inept use of this fuel, the air can be polluted with carbon monoxide and sulfur dioxide. There is local and central heating. The local system is common in countryside and small towns and is carried out using stoves. The best thermal effect is provided by furnaces of high heat capacity (Dutch furnace - Fig. 23), which, having inside a system of vertical and horizontal channels (smoke cycles) with hot flue gases passing through them, slowly heat up and maintain a more or less uniform temperature during the day at a single furnace. These stoves can also be used for room ventilation.

Rice. 23. Scheme of the Dutch oven.

In recent years, prolonged combustion furnaces have been used, in which the capacity of the firebox is increased, and the amount of air entering the furnace is minimized. Due to this, the combustion process slows down significantly and the heat transfer becomes more uniform over the course of the day.

Furnaces of low heat capacity are made of cast iron or steel, the inner walls of the firebox are lined with bricks.

Small portable ceramic ovens also fall into this category. Furnaces with low heat capacity quickly heat up and cool down after 1-2 hours, so they are suitable for short-term heating of people in temporary rooms. Furnace heating has a number of hygienic shortcomings: pollution of the premises during combustion with ash and fuel; the possibility of carbon monoxide entering the room air if the furnace is not closed in time; uneven heating of the surface, especially in the lower part; big square; fire hazard, etc.

More appropriate is central heating. Exist various systems central heating: water, steam, air, radiation (radiant).

Rice. 24. Scheme of water heating.

AT modern construction the most widely used low-pressure water heating (Fig. 24). With this system, water is heated in boilers located in the boiler room and is supplied through pipelines to heating appliances(radiators), which are installed indoors under window sills to weaken the effect of cold currents from windows and external walls. Having given off heat, the water returns to the boiler through another pipe system and heats up again. Water heating low pressure from a hygienic point of view is a favorable system, since it provides the necessary temperature conditions in the room and makes it possible to regulate the temperature of the heated water, taking into account the outdoor temperature, and prevent heating of the radiator surface above 85 °. In some cases (for example, in a separate pharmacy building), it is possible to equip a local water heating system, heating water either in a small cast-iron boiler in the kitchen, or in a boiler built into the stove, or, finally, in coils embedded in the stove chimneys. From here, heated water flows through pipelines to radiators installed in the premises (Fig. 25).

Rice. 25. Scheme local system water heating for small buildings.

Steam heating differs from water heating in that instead of water, steam enters the radiators. In view of this, the surface of the radiators is very hot, due to which dust can burn, and when touched, skin burns.

With steam heating, the room often overheats and air dryness is observed.

Air heating is used mainly in public institutions (cinemas, theaters, canteens, etc.) and is often combined with ventilation. Air is used as a heat carrier, which is heated to a certain temperature and is fed into the room through channels in the walls through holes closed by gratings.

From a hygienic point of view, radiation heating is very expedient. With this system, in the thickness of building fences (walls, ceiling, floor) heating devices(in the form of pipes with hot water or steam circulating in them, channels with hot air or electric coils) that radiate heat and heat them. The following temperatures of heated surfaces are recommended: floor - 24-34°, ceiling - 28-33°, walls - 45° ( building codes and rules II-D.7-62).

Radiant heating has a number of advantages over other systems: it ensures uniform distribution of heat in the room, due to the presence of large heating surfaces it reduces heat transfer by radiation, does not take usable space premises.

However, a radiant heating system is still more expensive than a central water heating system and is complex in terms of equipment; especially great difficulties are created during the repair.

At present, with the installation of central heating, instead of the previously existing separate small house boiler houses, central boiler houses are being built, supplying heat to groups of buildings or entire workers' settlements and small towns. Very promising is the district heating from combined heat and power plants (CHP), producing heat and electricity. From a hygienic point of view, the use of powerful CHPs for district heating has great advantages, since CHPs are usually located outside residential areas and have treatment facilities for flue emissions - all this significantly reduces air pollution in populated areas.

Distinguish between local or stove heating and central. The main difference is that in the first case, the combustion of fuel is carried out in heated rooms in the heating device itself (furnace), and in the second case, this process is taken out of their limits - the coolant (water, steam, air) is heated, which enters the heating pipes through pipes. devices (water, steam) or through channels directly into the room (heated air).

In modern building practice, systems of central water heating. Their advantage lies in the fact that from one heat generator, heated water can be supplied to apartments of any size, buildings, to a group of buildings, to all buildings of a block, or the whole city. The second is the ability to easily adjust the degree of water heating in the generator and, in addition, the availability of individual temperature control of heating devices directly in the apartment, in the room. It is possible to maintain a uniform temperature of the appliances, regardless of the duration of heating and in full accordance with the outside temperatures and setpoints. Steam heating of residential buildings, healthcare facilities, schools and kindergartens is prohibited for hygienic reasons. High heating temperatures of devices are always above 100C and threaten with burns, burning dust and create discomfort. The heating temperature cannot be changed depending on the outside temperatures. Steam heating is distinguished by the rapid heating of the system (small thermal inertia) and cooling after the steam supply is stopped. This makes it suitable for use in large rooms where operation requires a brief warm-up and then shutdown of the system, such as theaters. Air heating is based on heating the air in the heater, located in the basement of the building, which then enters through the channels to heat the premises. In multi-apartment buildings, air recirculation is unacceptable for general sanitary reasons, as well as the threat of spreading airborne pathogens through channels. The temperature of the supplied air must not exceed 50C. The advantage of air heating is economic in nature due to the absence of metal pipes and heating devices, as well as due to the speed of the thermal effect and the relative ease of operation of the system. The air supply should, in addition to heating, be accompanied by its filtration and humidification. Radiant heating. hallmark radiant heating is used to heat the enclosing surfaces of the room: the walls of the floor or ceiling. This is achieved due to the fact that heating pipes are laid under the fences or channels are included in the design of concrete panels of walls and fences. This type of heating is suitable for HCI DDU. The advantage is that due to the large heated enclosures, the heat loss by radiation from the surface of the body is noticeably reduced. Thanks to this, the comfort that occurs with conventional heating at an air temperature of 20 ° C can be achieved here at a temperature of 17 - 18 ° C.

77 Hygienic requirements for the heating system of residential and public buildings

The main task of heating is to create an optimal microclimate in the apartment.

Heating in the dwelling is organized both local and central.

Local heating is a heating system in which heat is produced where it is used. In local heating systems, the heat generator is combined into one unit with heat pipes and heating devices.

Disadvantages of local heating:

1. uneven air temperature in rooms during the day

2. the presence of negative radiation in the room (from windows and external walls);

3. relatively high temperature in certain areas of the surface of heating devices (furnaces), causing dust to burn and deterioration of the air composition in the premises;

4. pollution of premises with fuel, ash, smoke;

5. difficulty in regulating the heat transfer of heating surfaces;

6. danger of emission of harmful gases.

Central heating is devoid of these shortcomings - it provides a more uniform thermal regime in the room, there is no pollution by combustion products and fuel, more convenient and reliable control.

In apartments, water is used as a heat carrier. This avoids overheating of the surface of the heating devices. Heating systems, depending on the heat carriers, are divided into water, steam-water, air, etc. The most common are central water heating systems, because the water temperature in them does not exceed the regulated

According to the method of heat transfer, convective and radiative (radiant) heating devices are distinguished, and hence heating systems. With a convection system, convective (70-80%) prevails, that is, heat transferred by convection, and with radiation - radiation (radiant heat).

Examples of convective-type heating devices are a radiator and a convector. An example of radiant heating is the so-called panel heating, when the heating device is a panel (wall, ceiling or floor of a room). With such a heating system, heat transfer by radiation predominates, and negative radiative cooling from the outer walls of the room decreases in the room. Concrete heating panel - heating pipes are laid under the surface of the enclosing structures (floor, ceiling, walls), or they can be included in the design of concrete panels. As a result, the enclosing surfaces are heated: walls, ceiling or floor. When heated, heat is distributed almost entirely by radiation. Radiant heat has a more favorable effect on the human body, since the loss of heat due to radiation (from the thermal body of a person to the cold surface of the walls is a phenomenon of negative radiation) creates the most unpleasant thermal sensations. With radiant heating, the area of ​​the heated surface increases, therefore, heat loss by radiation decreases. Radiant heating prevents uneven cooling with different parties surface of the human body and reduces the possibility of cooling during ventilation. The feeling of thermal comfort in a person occurs at an ambient temperature of 170 C (when using radiators and convectors, the air temperature should be 200 C).

The most favorable physiological reactions and heat sensations in people are observed at a temperature of wall panels of 40-450, a ceiling of 28-300C, a floor of 25-270C - this prevents the occurrence of thermal discomfort associated with the high temperature of the enclosing structures. In this case, the air temperature in the room can be reduced to 17.50C.