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Heating calculation. Thermal calculation of the heating system Initial data for thermal calculation of the heating system

When designing heating and ventilation of automobile service enterprises, the requirements of SNiP 2.04.05-86 and these VSN must be observed

Estimated air temperatures during the cold period in industrial buildings should be taken:

in rolling stock storage rooms - + 5С

in warehouses - + 10С

in other rooms - according to the requirements of Table 1 GOST 12.1.005-86

Category Ib includes work performed while sitting or involving walking and accompanied by some physical stress (a number of professions in communications enterprises, controllers, foremen).

Category IIa includes work associated with constant walking, moving small (up to 1 kg) products or objects in a standing or sitting position and requiring little physical stress (a number of professions in spinning and weaving, mechanical assembly shops).

Category IIb includes work associated with walking and moving loads weighing up to 10 kg and accompanied by moderate physical stress (a number of professions in mechanical engineering and metallurgy).

Category III includes work associated with constant movement, moving and carrying significant (more than 10 kg) weights and requiring significant physical effort (a number of professions involving manual operations in metallurgical, mechanical engineering, and mining enterprises).

Heating of storage rooms, maintenance and repair stations of rolling stock, as a rule, should be provided by air, combined with fresh ventilation.

Heating with local heating devices with a smooth surface without fins is allowed in car storage rooms in one-story buildings with a volume of up to 10,000 m 3 inclusive, as well as in car storage rooms in multi-storey buildings regardless of volume.

4.4. In storage rooms, maintenance and repair stations of rolling stock, emergency heating should be provided using:

Supply ventilation switched to recirculation during non-working hours;

Heating and recirculation units;

Air-thermal curtains;

Local heating devices with a smooth surface without ribbing.

4.5. The heat requirement for heating rolling stock entering the premises should be taken in the amount of 0.029 watts per hour per kg of mass in running order per one degree difference in the temperatures of the external and internal air.

4.6. External gates of storage rooms, maintenance and repair stations of rolling stock should be equipped with air-thermal curtains in areas with an average design outside air temperature of 15 °C, and lower under the following conditions:

When there are five or more entries or exits per hour per gate in the premises of rolling stock maintenance and repair posts;

When maintenance posts are located at a distance of 4 meters or less from the external gate;

When there are 20 or more entries and exits per hour per gate in the storage area for rolling stock, except for passenger cars owned by citizens;

When storing 50 or more passenger cars belonging to citizens in the premises.

Thermal air curtains must be switched on and off automatically.

4.7. To ensure the required air conditions in storage rooms, maintenance and repair stations of rolling stock, general supply and exhaust ventilation with mechanical drive should be provided, taking into account the operating mode of the enterprise and the amount of harmful emissions installed in the technological part of the project.

4.8. In rolling stock storage rooms, including ramps, air removal should be provided equally from the upper and lower zones of the room; The supply of fresh air to the room should, as a rule, be carried out concentrated along the passages.

4.10. In the premises of maintenance and repair stations of rolling stock, air removal by general ventilation systems should be provided from the upper and lower zones equally, taking into account the exhaust from inspection ditches, and the supply of supply air should be dispersed into the working area and into inspection ditches, as well as into pits connecting inspection ditches , and into tunnels provided for exit from travel ditches.

The temperature of the supply air into inspection ditches, pits and tunnels during the cold season should not be lower than +16 °C and not higher than +25 °C.

The amount of supply and exhaust air per cubic meter of volume of inspection ditches, pits and tunnels should be taken based on their tenfold air exchange

4.12. In industrial premises connected through doors and gates without a vestibule with storage rooms and maintenance and repair stations, the volume of supply air should be taken with a coefficient of 1.05. At the same time, in storage rooms and maintenance and repair stations, the volume of supply air should be reduced accordingly.

4.13. In the premises of maintenance and repair stations of rolling stock at posts associated with the operation of vehicle engines, local suction should be provided.

The amount of air removed from operating engines, depending on their power, should be taken as follows:

up to 90 kW (120 hp) inclusive - 350 m 3 / h

St. 90 to 130 kW (120 to 180 hp) - 500 m 3 /h

St. 130 to 175 kW (180 to 240 hp) - 650 m 3 /h

St. 175 kW (240 hp) - 800 m 3 /h

The number of cars connected to the system of local suction with mechanical removal is not limited.

When placing no more than five posts for maintenance and repair of vehicles in a room, it is allowed to design local suction with natural removal for vehicles with a power of no more than 130 kW (180 hp)

The amount of engine exhaust gases escaping into the room should be taken as follows:

with hose suction - 10%

with open suction - 25%

4.16. Reception devices for supply ventilation systems must be located at a distance of at least 12 meters from the gate with the number of entries and exits of more than 10 cars per hour.

When the number of entries and exits is less than 10 cars per hour, the receiving devices of the supply ventilation systems can be located at a distance of at least one meter from the gate.

Air exchange in a car wash bay is calculated based on excess moisture. Air exchange in rooms with moisture release is determined by the formula, m3/hour: L=Lw,z+(W–1.2(dw,z–din)):1.2(dl–din), Lw,z - air flow rate removed local suction, m3/hour;

W - excess moisture in the room, g/hour;

tн - initial temperature of flowing water С;

tk - final temperature of flowing water С;

r – latent heat of evaporation, amounting to ~585 kcal/kg According to technological process 3 cars are washed within an hour. It takes 15 minutes to wash the car and 5 minutes to dry it. The amount of water used is 510 l/hour. The initial water temperature is +40С, the final temperature is +16С. For calculation, we assume that 10% of the water used in the technology remains on the surface of the car and on the floor. Air moisture content is determined using i – d diagrams. For supply air, we take the parameters for the most unfavorable period in terms of moisture content - the transition period: air temperature - + 8С, specific enthalpy - 22.5 kJ/kg. Based on this: W = 0.1 (510 x (40 - 16) : 585) = 2.092 kg/hour = 2092 g/hour. Lvl. =2092: 1.2 (9 –5.5) = 500 m3/h.

SNiP 2.01.57-85

ADAPTATION OF CAR WASHING AND CLEANING ROOMS FOR SPECIAL TREATMENT OF ROLLING STOCK

6.1. When designing the adaptation of new or reconstruction of existing motor transport enterprises, centralized vehicle maintenance bases, vehicle service stations, vehicle washing and cleaning posts should be provided with travel passes.

6.2. Special processing of rolling stock should be carried out on production lines and drive-through posts in car washing and cleaning rooms. At existing enterprises, dead-end car washing and cleaning stations should not be adapted for special processing of rolling stock. When designing special processing of rolling stock, it is necessary to take into account the sequence of operations:

control of contamination of rolling stock (if it is contaminated with radioactive substances);

cleaning and washing of external and internal surfaces of rolling stock (if it is contaminated with radioactive substances);

application of neutralizing substances to the surface of the rolling stock (during degassing and disinfection);

exposure (during disinfection) of applied substances to the surface of rolling stock;

washing off (removing) disinfectants;

re-monitoring the degree of contamination of the rolling stock radioactive substances and, if necessary, repeating decontamination;

lubrication of surfaces of parts and tools made of easily corrosive materials.

6.3. When specially processing rolling stock, at least two sequentially located work stations should be used.

The work station of the “clean” zone, intended for repeated control of contamination and for lubrication, may be located separately from the “dirty” zone in an adjacent room or outside the building - on the territory of the enterprise.

Work stations of the “dirty” and “clean” zones, located in the same room, should be separated by partitions with openings for the passage of cars. Openings must be equipped with waterproof curtains.

6.4. In one room it is allowed to place two or more parallel streams for special processing of rolling stock, while the posts of “dirty” zones of parallel streams must be isolated from one another by partitions or screens with a height of at least 2.4 m.

The distances between the sides of the rolling stock and the screens must be no less than: passenger cars - 1.2 m; trucks and buses - 1.5 m.

The distances between the end sides of the rolling stock, partitions, curtains or external gates should be taken in accordance with the standards.

6.5. At posts for special processing of rolling stock in the “dirty” area, it is necessary to install work tables with a metal or plastic coating, as well as metal containers with neutralizing solutions for special processing of components, parts and tools removed from vehicles.

In the “clean” area, provision should be made for the installation of work tables for re-inspection and lubrication of removed units, parts and tools.

6.6. Washing equipment and work tables located in the “dirty” and “clean” areas should be provided with a supply of cold and hot water, as well as compressed air, through a mixer.

The water temperature for washing rolling stock using mechanized installations is not standardized. When washing with a hose manually, the water temperature should be 20 - 40 °C.

6.7. Work stations in the “dirty” and “clean” zones for work in the lower part of the rolling stock must be equipped with inspection ditches, overpasses or lifts. The dimensions of the working area of ​​the inspection ditches should be taken in accordance with table. 6.

Table 6

Steps in the inspection ditch should be provided in the end part from the side of vehicle entrances to work stations without the construction of tunnels (passages).

6.8. The throughput capacity of the section for special processing of rolling stock is given in the mandatory Appendix 1.

Approximate layouts and equipment of work stations in a room for two parallel production lines and one drive-through station are given in the recommended Appendix 2.

6.9. In the same building with a room for special processing of rolling stock, it is necessary to provide separate rooms for storing special processing equipment and materials. The area of ​​the room should be taken depending on the throughput of the area for disinfection of the composition, but not less than 8 m 2. The entrance to the premises should be from a “clean” area. The room must be equipped with shelving.

6.10. Room for service personnel and the sanitary checkpoint, as a rule, should be located in the same building with special processing posts for rolling stock.

The room for service personnel must have an entrance from the “clean” area.

For sanitary checkpoints, it is allowed to adapt sanitary facilities (with two shower nets or more) located in other buildings of the enterprise.

6.11. The requirements for the sanitary checkpoint for servicing personnel, rolling stock drivers and accompanying persons, for the composition and size of its premises are similar to the requirements set out in section 3.

6.12. The finishing of walls and partitions, as well as the installation of floors in rooms for special processing of rolling stock, must comply with the requirements of technological design standards , as well as the requirements of paragraph. 1.5 real standards.

The floors of the premises for special processing of rolling stock must have a slope of 0.02 towards the inspection ditches, the floors of which must have a slope towards the outlet Wastewater.

6.13. In special processing rooms for rolling stock, rooms for service personnel and in the warehouse for contaminated clothing, watering taps should be provided for washing floors.

6.14. Wastewater from premises adapted for special treatment of rolling stock must be supplied to treatment facilities for recycling water supply. Used in usual time When sanitizing transport, treatment facilities must be switched to a direct-flow scheme without changing the treatment scheme.

The residence time of wastewater in treatment facilities must be at least 30 minutes. After treatment, wastewater must be discharged into the domestic or storm sewer system.

Sediment or oils from treatment facilities should be exported to places agreed upon with the local sanitary and epidemiological station.

6.15. Supply and exhaust ventilation must provide an hourly air exchange rate of at least 10 in the “dirty” zone of production premises and sanitary passage. Supply air should be supplied only to the “clean” zone.

The exhaust should be concentrated from the upper part of the room, with 2/3 from the “dirty” zone and 1/3 of the volume of sucked air from the “clean” zone.

When the work stations of the “clean” zone are located separately from the “dirty” zone (outside the building - on the territory of the enterprise), supply air should be supplied to the work stations of the “dirty” zone.

The exhaust air volume should be 20% greater than the supply air volume.

ANNEX 1Mandatory

This mandatory appendix provides data to SNiP 2.01.57-85 “Adaptation of public utility facilities for sanitary treatment of people, special treatment of clothing and rolling stock of vehicles,” developed to replace SN 490-77.

3.2 Heating calculation

Calculation of heat for heating an industrial premises is calculated using the formula:

Q t = V * q * (t in – t n), (3.5)

where V is the estimated volume of the room; V =120 m³

q – specific rate fuel consumption per 1 m 3; q =2.5

t in – air temperature in the room; t in = 18ºС

t n – minimum outside air temperature. t n = -35ºС

Q t = 120 * 2.5 * (18 - (- 35)) = 15900 J/hour.

3.3 Calculation of ventilation

The required approximate air exchange in the premises can be determined through the air exchange rate using the formula:

where L is air exchange in the room;

V – volume of the room;

K – air exchange rate, K=3

L = 120 * 3 = 360 m 3 /hour.

We select a centrifugal fan of the VR series No. 2, electric motor type AOA-21-4.

n - rotation speed – 1.5 thousand rpm;

L in – fan capacity – 400 m 3 /hour;

Нв – pressure created by the fan – 25 kg/m2;

η in – coefficient useful action fan – 0.48;

η p - transmission efficiency – 0.8.

The choice of electric motor based on installed power is calculated using the formula:

N dv = (1.2/1.5) * ------- (3.7)

3600 * 102 * η in* η p

N dv = (1.2/1.5) * --------- = 0.091 kW

3600 * 102 * 0,48 * 0,8

We accept power N dv = 0.1 kW

Bibliography.

  1. SNiP 2.04.05-86 Heating, ventilation and air conditioning

  2. SNiP 21 - 02 - 99* "Car parking"

    VSN 01-89 "Car service enterprises" section 4.

    GOST 12.1.005-88 "General sanitary and hygienic requirements for air in the working area"

    ONTP-01-91 "All-Union standards for technological design of automobile transport enterprises" Section 3.

    SNiP 2.01.57-85ADAPTATION OF MUNICIPAL SERVICE FACILITIESPURPOSE FOR SANITARY TREATMENT OF PEOPLE,SPECIAL PROCESSING OF CLOTHING AND MOBILECOMPOSITION OF MOTOR TRANSPORT section 6.

    GOST 12.1.005-88 section 1.

GENERAL SANITARY AND HYGIENIC REQUIREMENTS FOR AIR IN THE WORKING AREA

    SNiP 2.04.05-91*

    SNiP 2.09.04-87*

    SNiP 41-01-2003 section 7.

  1. Sp 12.13130.2009 Determination of categories of premises, buildings and outdoor installations according to explosion and fire hazard (with Change n 1)

  2. SNiP II-g.7-62 Heating, ventilation and air conditioning. Design standards

13. SNiP 23 – 05 – 95. Natural and artificial lighting. –M.: State Unitary Enterprise TsPP, 1999

L.1 Supply air flow L, m 3 / h, for the ventilation and air conditioning system should be determined by calculation and take the greater of the costs required to ensure:

a) sanitary and hygienic standards in accordance with L.2;

b) fire and explosion safety standards in accordance with L.Z.

L.2 Air flow should be determined separately for the warm and cold periods of the year and transition conditions, taking the larger of the values ​​obtained from formulas (L.1) - (L.7) (with a density of supply and exhaust air equal to 1.2 kg /m 3):

a) by excess sensible heat:

When simultaneously releasing several harmful substances having the effect of summation of action, air exchange should be determined by summing up the air flow rates calculated for each of these substances:

a) for excess moisture (water vapor):

c) according to the normalized air exchange rate:

,

d) according to the standardized specific flow rate of supply air:

,

,

In formulas (L.1) - (L.7):

L wz- consumption of air removed from the serviced or working area of ​​the premises by local suction systems and for technological needs, m 3 /h;

Q, Q hf - excess sensible and total heat flows into the room, W; c - heat capacity of air equal to 1.2 kJ/(m 3 ∙°C);

t wz. - temperature of the air removed by local suction systems in the serviced or working area of ​​the room and on technological needs, °C;

t 1 - temperature of air removed from the room outside the serviced or working area, °C;

t in- temperature of air supplied to the room, °C, determined in accordance with L.6;

W - excess moisture in the room, g/h;

d wz- moisture content of air removed from the serviced or working area of ​​the premises by local suction systems, and for technological needs, g/kg;

d 1 - moisture content of air removed from the premises outside the serviced or working area, g/kg;

d in- moisture content of air supplied to the room, g/kg;

I wz- specific enthalpy of air removed from the serviced or working area of ​​the premises by local suction systems, and for technological needs, kJ/kg;

I 1 - specific enthalpy of air removed from the room outside the serviced or working area, kJ/kg;

I in- specific enthalpy of air supplied to the room, kJ/kg, determined taking into account the temperature increase in accordance with L.6;

m ro- consumption of each of the harmful or explosive substances entering the air in the room, mg/h;

q wz , q 1 - concentration of a harmful or explosive substance in the air removed from the serviced or working area of ​​the room and beyond, respectively, mg/m 3 ;

q in- concentration of harmful or explosive substance in the air supplied to the room, mg/m3;

V R- volume of the room, m3; for rooms with a height of 6 m or more should be taken

,

A- area of ​​the room, m2;

N- number of people (visitors), workplaces, pieces of equipment;

n- normalized air exchange rate, h -1;

k- normalized supply air flow per 1 m 2 of room floor, m 3 / (h∙m 2);

m- standardized specific flow rate of supply air per 1 person, m 3 /h, per 1 workplace, per 1 visitor or piece of equipment.

Air parameters t wz , d wz , I wz should be taken equal to the design parameters in the serviced or working area of ​​the premises according to Section 5 of these standards, a q wz- equal to the maximum permissible concentration in the working area of ​​the room.

L.3 Air flow to ensure explosion and fire safety standards should be determined using formula (L.2).

Moreover, in formula (L.2) q wz And q 1 , should be replaced by 0.1 q g, mg/m 3 (where q g- lower concentration limit of flame propagation through gas, steam and dust-air mixtures).

L.4 Air flow L he, m 3 / h, for air heating, not combined with ventilation, should be determined by the formula

,

Where Q he heat flow for space heating, W

t he- the temperature of heated air, °C, supplied to the room is determined by calculation.

L.5 Air flow L mt from intermittently operating ventilation systems with rated capacity L d, m 3 / h, is based on n, min, interrupted by system operation for 1 hour according to the formula

b) with outside air cooled by circulating water through an adiabatic cycle, reducing its temperature by ∆t 1 °C:

d) with outside air cooled by circulating water (see subparagraph “b”) and local additional humidification (see subparagraph “c”):

Where R- total fan pressure, Pa;

t ext- outside air temperature, °C.

Expert opinion

Fedorov Maxim Olegovich

Production facilities differ significantly from residential apartments their sizes and volumes. This is the fundamental difference between industrial ventilation systems and domestic systems. Options for heating spacious non-residential buildings exclude the use of convection methods, which are quite effective for heating housing.

The large size of production workshops, the complexity of the configuration, the presence of many devices, units or machines that allocate space thermal energy, will disrupt the convection process. It is based on the natural process of rising warm layers of air; the circulation of such flows does not tolerate even small interventions. Any draft, hot air from an electric motor or machine, will direct the flow in the other direction. In industrial workshops, warehouses there are large technological openings that can stop the heating systems from working low power and sustainability.

In addition, convection methods do not provide uniform heating of the air, which is important for production premises. Large areas require the same air temperature at all points in the room, otherwise there will be difficulties for people to work and flow production processes. Therefore, for industrial premises specific heating methods are required, capable of providing the correct microclimate, appropriate.

Industrial heating systems

Among the most preferred heating methods industrial premises includes:

  • infrared

In addition, there are two options for the type of area coverage:
  • centralized

  • zonal

Centralized systems

Centralized systems are created to ensure maximum uniform heating of all areas of the workshop. This can be important when there are no specific workplaces or the need for constant movement of people throughout the entire workshop area.

Zone systems

Zonal heating systems create areas with a comfortable microclimate in workplaces without completely covering the workshop area. This option makes it possible to save money by not wasting resources and thermal energy on ballast heating of unused or unvisited areas of the workshop. At the same time, the technological process must not be disrupted; the air temperature must meet the technological requirements.

Electric heating

Expert opinion

Heating and ventilation engineer RSV

Fedorov Maxim Olegovich

Important! It should immediately be noted that heating with electricity as the main method of heating practically not used due to its high cost.

Electric heat guns or air heaters are used as temporary or local heat sources. For example, for production repair work installed in an unheated room heat gun, allowing the repair team to work in comfortable conditions that allow them to obtain required quality work. Electric heaters as temporary heat sources are the most popular, as they do not require coolant. They only need to be connected to the network, after which they immediately begin to generate thermal energy on their own. Wherein, The serviced areas are quite small.

Air heating

Expert opinion

Heating and ventilation engineer RSV

Fedorov Maxim Olegovich

Air heating of industrial buildings is the most attractive type of heating.

It allows you to heat large rooms, regardless of their configuration. Distribution air flow occurs in a controlled manner, the temperature and air composition are flexibly regulated. The operating principle is to heat the supply air using gas burners, electric or water heaters. Hot air using a fan and an air duct system, it is transported to production premises and released at the most convenient points, ensuring maximum uniformity of heating. Air heating systems have high maintainability, they are safe and allow you to fully ensure the microclimate in production premises.

Infrared heating

Expert opinion

Heating and ventilation engineer RSV

Fedorov Maxim Olegovich

Infrared heating - one of the newest, which appeared relatively recently, heating methods production premises. Its essence is to use infrared rays to heat all surfaces located in the path of the rays.

Typically the panels are located under the ceiling, radiating from top to bottom. This heats up the floor, various objects, and to some extent the walls.

Expert opinion

Heating and ventilation engineer RSV

Fedorov Maxim Olegovich

Important! This is the peculiarity of the method - It is not the air that is heated, but the objects located in the room.

For more efficient distribution of IR rays, the panels are equipped with reflectors that direct the flow of rays into the right side. The method of heating with infrared rays is effective and economical, but is dependent on the availability of electricity.

Advantages and disadvantages

Electric heating

Heating systems used to heat private homes or industrial buildings have their own strengths and weak sides. So, advantages electrical methods heating are:

  • absence of intermediate materials (coolant). Electrical appliances themselves generate thermal energy

  • high maintainability devices. All elements can be quickly replaced in case of failure without any specific repair work

  • an electrically heated system can be very Flexibly and precisely adjustable. At the same time, no complex complexes are required; control is carried out using standard blocks

Disadvantage Electric heating systems are expensive. At the same time, the devices themselves are quite expensive, and the electricity they consume creates significant costs. This is the main reason for the rare use of electrical appliances as the main heating system.

Infrared heating

Infrared systems have advantages:

  • efficiency, efficiency

  • oxygen is not burned, air humidity that is comfortable for humans is maintained

  • installation such a system is enough simple and accessible for self-execution

  • system No worries about voltage surges, which allows you to maintain the indoor microclimate even when connected to an unstable power supply network

Flaws IR heating:
  • The technique is intended primarily for local, spot heating. Using it to create an even microclimate in large workshops it is irrational

  • complexity of system calculation, the need for precise selection of suitable devices

Air heating

Air heating is considered the most in a convenient way heating industrial and residential premises. This is expressed in the following benefits:

  • ability uniform heating of large workshops or premises of any size

  • the system can be reconstructed, its power can be increased if necessary without complete dismantling

  • air heating most safe to use and installation

  • system has low inertia and can quickly change operating modes

  • exists many options

Disadvantages air heating are:
  • dependence on heating source

  • addiction depending on availability connection to the electricity network

  • upon failure system temperature the room is very falls quickly

All these qualities are criteria for choosing a heating system when designing.

Creating a heating system project

Expert opinion

Heating and ventilation engineer RSV

Fedorov Maxim Olegovich

Designing air heating is not an easy task. To solve it, it is necessary to clarify a number of factors, self-determination which may be difficult. RSV company specialists can make a preliminary one for you free of charge premises based on GREERS equipment.

The choice of one or another type of heating system is made by comparing climatic conditions region, building size, ceiling height, features of the proposed technological process, location of workplaces. In addition, when choosing, they are guided by the cost-effectiveness of the heating method and the possibility of using it without extra costs.

The system is calculated by determining heat losses and selecting equipment that matches them in terms of power. To eliminate the possibility of errors SNiP must be used, which sets out all the requirements for heating systems and gives the coefficients necessary for calculations.

SNiP 41-01-2008

HEATING, VENTILATION AND AIR CONDITIONING

ADOPTED AND ENTERED INTO EFFECT from 01/01/2008 by decree of 2008. INSTEAD SNiP 41-01-2003

Heating system installation

Expert opinion

Heating and ventilation engineer RSV

Fedorov Maxim Olegovich

Important! Installation work are manufactured in strict accordance with the design and SNiP requirements.

Air ducts are an important element of the system, which provide transportation of gas-air mixtures. They are installed in each building or room according to individual scheme. The size, cross-section, and shape of the air ducts play an important role during installation, since to connect the fan, adapters are needed that connect the inlet or outlet pipe of the device to the air duct system. Without high-quality adapters, it will not be possible to create a tight and efficient connection.

In accordance with the selected type of system, installations are carried out. electrical cables , is done pipe layout for coolant circulation. The equipment is installed, all necessary connections and connections are made. All work is carried out in compliance with safety requirements. The system is started in the minimum operating mode, with a gradual increase in design power.

Useful video

On this website tab we will try to help you choose the right parts of the system for your home. Any node has an important role. Therefore, the selection of installation parts must be planned technically correctly. The heating system has thermostats, a connection system, fasteners, air vents, an expansion tank, batteries, manifolds, boiler pipes, and pressure-increasing pumps. Installation of apartment heating includes various elements.

To make heating calculations, you need to calculate how much heat is required to maintain optimal temperature in the cold season. This value will be equal to the heat that the apartment loses when minimum temperatures(about 30 degrees).

When taking into account heat loss, attention is paid to the level of thermal insulation of windows and doors, the thickness of the walls and the material of the building itself. If the calculation of the apartment heating system is ultimately 10 kW, this value will determine not only the boiler power, but also the number of radiators.

The higher the energy efficiency of an apartment, the less energy is required to heat it. To achieve this result, you should replace the windows with modern energy-saving ones, pay attention doorways And ventilation system, insulate the walls inside or outside the apartment.

The degree of heating of the apartment depends on the movement of the coolant. Its speed may depend on several factors:

  • Pipe section. The larger the diameter, the faster the coolant will move.
  • Curves and length of the section. According to a complex pattern, the liquid circulates more slowly
  • Pipe material. When comparing iron and plastic, then latest version there will be less resistance, which means the coolant speed will be higher.

All these indicators determine hydraulic resistance.

Calculation of heating in industrial buildings

The most common option is water heating. It has many schemes that should be taken into account according to the individual characteristics of the structure. The main calculations are hydraulic and thermal. High-quality heating pipes and heating mains will help you avoid many problems in the future. This type of heating is most suitable for residential and administrative types of buildings and offices.

The air type is based on the operation of a heat generator that heats the air to circulate it throughout the system. Calculation of an air heating system is the main step for creating effective system. It is advisable to use in shopping centers, industrial and production buildings.

Direct calculation of the heating system of an industrial building requires the approach of qualified specialists and attention, otherwise many negative consequences may arise.

Common mistakes and how to fix them

The calculation of the heating system itself is an important and complex stage in the development of heating. Special computer programs help specialists perform all calculations. However, errors may still occur.

One of the common problems is the incorrect calculation of the thermal power of the heating system or the lack thereof. Except high cost on radiators, their high power will cause the entire system to become unprofitable. That is, the heating will work more than necessary, wasting fuel on it. Heat the room will burn a lot of oxygen and require regular ventilation to reduce its indicator.

Completed: Art. gr.VI-12

Tsivaty I.I.

Dnepropetrovsk 2011

1 . Ventilation as a means of protection in industrial air environment premises

The task of ventilation is to ensure air purity and specified meteorological conditions in production premises. Ventilation is achieved by removing polluted or heated air from a room and introducing fresh air into it.

Depending on the site of action, ventilation can be general exchange or local. The action of general exchange ventilation is based on diluting polluted, heated, humid indoor air with fresh air to the maximum acceptable standards. This ventilation system is most often used in cases where harmful substances, heat, and moisture are released evenly throughout the room. With such ventilation, the required parameters are maintained air environment throughout the entire room.

Air exchange in a room can be significantly reduced if harmful substances are captured at the points of their release. To this end technological equipment, which is a source of release of harmful substances, is equipped with special devices from which polluted air is sucked out. This type of ventilation is called local exhaust. Local ventilation, compared to general ventilation, requires significantly lower costs for installation and operation.

Natural ventilation

Air exchange during natural ventilation occurs due to the difference in temperature between the air in the room and the outside air, as well as as a result of the action of wind. Natural ventilation can be unorganized and organized. With unorganized ventilation, the intake and removal of air occurs through the density and pores of external fences (infiltration), through windows, vents, and special openings (ventilation). Organized natural ventilation is carried out by aeration and deflectors, and can be adjusted.

Aeration is carried out in cold shops due to wind pressure, and in hot shops due to the combined and separate action of gravitational and wind pressure. IN summer time Fresh air enters the room through lower openings located at a small height from the floor (1-1.5 m), and is removed through openings in the building's skylight.

Mechanical ventilation

In systems mechanical ventilation Air movement is carried out by fans and, in some cases, ejectors. Forced ventilation. Supply ventilation installations usually consist of the following elements: an air intake device for taking in clean air; air ducts through which air is supplied to the room; filters for air purification from dust; air heaters for heating air; fan; supply nozzles; control devices that are installed in the air intake device and on the branches of the air ducts. Exhaust ventilation. Settings exhaust ventilation include: exhaust openings or nozzles; fan; air ducts; device for purifying air from dust and gases; a device for releasing air, which should be located ? 1.5 m above the roof ridge. When the exhaust system is operating fresh air enters the room through leaks in the enclosing structures. In some cases, this circumstance is a serious drawback of this ventilation system, since an unorganized influx of cold air (drafts) can cause colds. Supply and exhaust ventilation. In this system, air is supplied to the room by supply ventilation and removed by exhaust ventilation, operating simultaneously.

Local ventilation

Local ventilation can be supply or exhaust. Local forced ventilation serves to create the required air conditions in a limited area of ​​the production premises. Local supply ventilation installations include: air showers and oases, air and air-thermal curtains. Air showering is used in hot shops at workplaces under the influence of a radiant heat flow with an intensity of 350 W/m or more. An air shower is a stream of air directed at the worker. The blowing speed is 1-3.5 m/s depending on the intensity of irradiation. The effectiveness of showering units increases when water is sprayed in a stream of air.

Air oases are part production area, which is separated on all sides by light movable partitions and filled with air that is colder and cleaner than the air in the room. Air and air-thermal curtains are installed to protect people from being chilled by cold air penetrating through the gate. There are two types of curtains: air curtains with air supply without heating and air-thermal curtains with heating of the supplied air in heaters.

The operation of the curtains is based on the fact that the air supplied to the gate exits through a special air duct with a slot at a certain angle with high speed(up to 10-15 m/s) towards the incoming cold flow and mixes with it. The resulting mixture of warmer air enters the workplace or (if the heating is insufficient) is deflected away from them. When the curtains operate, additional resistance is created to the passage of cold air through the gate.

Local exhaust ventilation. Its use is based on the capture and removal of harmful substances directly at the source of their formation. Local exhaust ventilation devices are made in the form of shelters or local suction. Shelters with suction are characterized by the fact that the source of harmful emissions is located inside them.

They can be made as shelters - casings that completely or partially enclose the equipment ( fume hoods, display cases, booths and chambers). A vacuum is created inside the shelters, as a result of which harmful substances cannot enter the indoor air. This method of preventing the release of harmful substances in a room is called aspiration.

Aspiration systems are usually blocked with starting devices of process equipment so that harmful substances are sucked out not only at the point of their release, but also at the moment of formation.

Complete shelter of machines and mechanisms that emit harmful substances, the most advanced and effective method preventing their release into the indoor air. It is important, even at the design stage, to develop technological equipment in such a way that ventilation devices would be organically included in the overall design, without interfering with the technological process and at the same time completely solving sanitary and hygienic problems.

Protective and dust-removing casings are installed on machines where the processing of materials is accompanied by the release of dust and the flying off of large particles that can cause injury. These are grinding, roughing, polishing, sharpening machines metal, woodworking machines, etc.

Fume hoods are widely used in thermal and galvanic processing of metals, painting, hanging and packaging bulk materials, at various operations associated with the release of harmful gases and vapors.

Cabins and chambers are containers of a certain volume, inside of which work is carried out related to the release of harmful substances (sandblasting and shot blasting, painting work, etc.). Exhaust hoods are used to localize harmful substances rising upward, namely during heat - and moisture releases.

Suction panels are used in cases where the use of exhaust hoods is unacceptable due to the entry of harmful substances into the respiratory organs of workers. An effective local suction is the Chernoberezhsky panel, used in operations such as gas welding, soldering, etc.

Dust and gas receivers and funnels are used for soldering and welding work. They are located in close proximity to the soldering or welding site. Onboard suctions. When etching metals and applying electroplating, vapors of acids and alkalis are released from the open surface of the baths; during galvanizing, copper plating, silver plating - extremely harmful hydrogen cyanide; during chrome plating - chromium oxide, etc.

To localize these harmful substances, side suctions are used, which are slot-like air ducts 40-100 mm wide, installed along the periphery of the baths.

2. Initial data for design

heat gain exhaust supply ventilation

· name of the object - woodworking shop;

· option - B;

· construction area - Odessa;

· room height -10 m;

Availability of machines:

1 end CPA - 1.9 kW;

2 Planing SP30-І 4-sided - 25.8 kW;

3 Prireznoy PDK-4-2 - 14.8 kW;

4 Thicknesser single-sided CP6-6- 9.5 kW;

5 Jointer SF4-4 - 3.5 kW;

6 Tenoner 2-sided ШД-15-3 - 28.7 kW;

7 Tenoner one-sided ШОІО-А- 11.2 kW;

8 For drilling and sealing knots SVSA-2-3.5 kW;

9 Band saw - 5.9 kW;

10 Horizontal drilling - 5.9 kW;

11 Drilling and grooving machine SVP-2 - 3.5 kW;

12 Thicknesser single-sided CP12-2 - 33.7 kW;

13 Grinding 3-cylinder SHPATS 12-2- 30.7 kW;

14 Bench - drilling - 1.4 kW;

15 For selecting sockets for C-4 loops - 4.4 kW;

16 For selecting sockets for S-7 locks - 3.3 kW;

17 Chain-forming DSA - 6.2 kW;

18 Universal Ts-6 - 7.8 kW;

Heating calculation

In order to determine the size as correctly as possible required quantity fuel, to calculate kilowatts of heating, and also to calculate the greatest efficiency of the heating system, subject to the use of an agreed type of fuel, specialists from housing and communal services have created a special methodology and program for calculating heating, which makes it much easier to obtain the necessary information using previously known factors .

This technique allows you to correctly calculate heating - required quantity fuel of any type.

And, in addition, the results obtained are an important indicator, which is certainly taken into account when calculating tariffs for housing and communal services, as well as when drawing up an estimate of the financial needs of this organization. Let us answer the question of how to correctly calculate heating based on increased indicators.

Features of the technique

This technique, which can be used using a heating calculation calculator, is regularly used to calculate the technical and economic efficiency of implementation various types energy saving programs, as well as during the use of new equipment and the launch of energy efficient processes.

In order to calculate the heating of a room - calculate the heat load (hourly) in the heating system separate building, you can use the formula:

In this formula for calculating the heating of a building:

  • a is a coefficient showing a possible correction for the difference in external air temperature when calculating the operating efficiency of the heating system, where to from to = -30°C, and at the same time the necessary parameter q 0 is determined;
  • The indicator V (m 3) in the formula is the external volume of the heated building (it can be found in project documentation building);
  • q 0 (kcal/m3 h°C) is a specific characteristic when heating a building, taking into account t o = -30°C;
  • K.r acts as an infiltration coefficient, which takes into account additional characteristics such as wind force and heat flow. This indicator indicates the calculation of heating costs - this is the level of heat loss of the building due to infiltration, while heat transfer is carried out through the external enclosure, and the external air temperature applied to the entire project is taken into account.

If the building for which online heating calculations are carried out has an attic (attic floor), then the V indicator is calculated by multiplying the indicator of the horizontal section of the building (meaning the indicator obtained at the floor level of the 1st floor) by the height of the building.

In this case, the height is determined to the top point of thermal insulation attic space. If the roof of the building is combined with attic floor, then the heating calculation formula uses the height of the building to the midpoint of the roof. It should be noted that if there are protruding elements and niches in the building, they are not taken into account when calculating the V indicator.

Before heating is calculated, it should be taken into account that if the building has a basement or basement that also needs heating, then 40% of the area of ​​this room should be added to the V indicator.

To determine the K i.r indicator, the following formula is used:

wherein:

  • g – acceleration obtained during free fall (m/s 2);
  • L – height of the house;
  • w 0 – according to SNiP 23-01-99 – the conditional value of the wind speed present in a given region during the heating season;

In those regions where the calculated external air temperature t 0 £ -40 is used, when creating a heating system project, before calculating the heating of the room, a heat loss of 5% should be added. This is permissible in cases where it is planned that the house will have an unheated basement. This heat loss is caused by the fact that the floor of the premises on the 1st floor will always be cold.

For stone houses, the construction of which has already been completed, the higher heat loss during the first heating period should be taken into account and certain adjustments should be made. At the same time, heating calculations based on aggregated indicators take into account the completion date of construction:

May-June - 12%;

July-August – 20%;

September – 25%;

Heating season (October-April) – 30%.

To calculate the specific heating characteristics of a building q 0 (kcal/m 3 h) should be calculated using the following formula:

Hot water supply

Wherein:

  • a – consumption rate hot water subscriber (l/unit) per day. This indicator is approved by local authorities. If the standard is not approved, the indicator is taken from the table SNiP 2.04.01-85 (Appendix 3).
  • N is the number of residents (students, workers) in the building, related to the day.
  • t c – indicator of the temperature of water supplied during the heating season. If this indicator is missing, an approximate value is taken, namely t c = 5 °C.
  • T – a certain period of time per day when hot water is supplied to the subscriber.
  • Q t.p – indicator of heat loss in the hot water supply system. Most often, this indicator reflects the heat loss of the external circulation and supply pipelines.

To determine the average heat load of the hot water supply system during the period when the heating is turned off, calculations should be made using the formula:

  • Q hm – average value level of heat load of the hot water supply system during the heating period. Unit of measurement - Gcal/h.
  • b – an indicator demonstrating the degree of reduction in the hourly load in the hot water supply system during the non-heating period, compared to the same indicator during the heating period. This indicator should be determined by the city government. If the value of the indicator is not determined, the average parameter is used:
  • 0.8 for housing and communal services of cities located in central Russia;
  • 1.2-1.5 is an indicator applicable to southern (resort) cities.

For enterprises located in any region of Russia, a single indicator is used - 1.0.

  • t hs, t h - indicator of the temperature of hot water supplied to subscribers during the heating and non-heating periods.
  • t cs, t c – indicator of the temperature of tap water during the heating and non-heating periods. If this indicator is unknown, you can use averaged data - tcs = 15 °C, tc = 5 °C.

The coziness and comfort of housing does not begin with the choice of furniture, decoration and appearance generally. They start with the heat that heating provides. And simply purchasing an expensive heating boiler () and high-quality radiators for this purpose is not enough - first you need to design a system that will maintain the optimal temperature in the house. But to get a good result, you need to understand what should be done and how, what nuances exist and how they affect the process. In this article you will become familiar with the basic knowledge about this matter - what heating systems are, how it is carried out and what factors influence it.

Why is thermal calculation necessary?

Some owners of private houses or those who are just planning to build them are interested in whether there is any point in the thermal calculation of the heating system? After all, we're talking about something simple. country cottage, not about apartment building or industrial enterprise. It would seem that it would be enough just to buy a boiler, install radiators and run pipes to them. On the one hand, they are partially right - for private households, the calculation of the heating system is not as critical an issue as for industrial premises or multi-apartment residential complexes. On the other hand, there are three reasons why such an event is worth holding. , you can read in our article.

  1. Thermal calculation significantly simplifies the bureaucratic processes associated with gasification of a private home.
  2. Determining the power required for heating a home allows you to select a heating boiler with optimal characteristics. You will not overpay for excessive product characteristics and will not experience inconvenience due to the fact that the boiler is not powerful enough for your home.
  3. Thermal calculation allows you to more accurately select pipes, shut-off valves and other equipment for the heating system of a private home. And in the end, all these rather expensive products will work for as long as is included in their design and characteristics.

Initial data for thermal calculation of the heating system

Before you begin to calculate and work with data, you need to obtain it. Here for those owners country houses who have not previously engaged in project activities, the first problem arises - what characteristics should be paid attention to. For your convenience, they are summarized in a short list below.

  1. Building area, ceiling height and internal volume.
  2. Type of building, presence of adjacent buildings.
  3. Materials used in the construction of the building - what and how the floor, walls and roof are made of.
  4. The number of windows and doors, how they are equipped, how well they are insulated.
  5. For what purposes will these or those parts of the building be used - where the kitchen, bathroom, living room, bedrooms will be located, and where - non-residential and technical premises.
  6. Duration heating season, the average minimum temperature during this period.
  7. “Wind rose”, the presence of other buildings nearby.
  8. An area where a house has already been built or is about to be built.
  9. Preferred temperature for residents in certain rooms.
  10. Location of points for connecting to water supply, gas and electricity.

Calculation of heating system power based on housing area

One of the fastest and easiest to understand ways to determine the power of a heating system is to calculate the area of ​​the room. This method is widely used by sellers of heating boilers and radiators. Calculating the power of a heating system by area occurs in a few simple steps.

Step 1. Based on the plan or already erected building, the internal area of ​​the building in square meters is determined.

Step 2. The resulting figure is multiplied by 100-150 - that’s exactly how many watts from total power A heating system is needed for every m2 of housing.

Step 3. Then the result is multiplied by 1.2 or 1.25 - this is necessary to create a power reserve so that the heating system is able to maintain a comfortable temperature in the house even in the event of the most severe frosts.

Step 4. The final figure is calculated and recorded - the power of the heating system in watts required to heat a particular home. As an example - to maintain comfortable temperature in a private house with an area of ​​120 m2, approximately 15,000 W will be required.

Advice! In some cases, cottage owners divide the internal area of ​​​​the housing into that part that requires serious heating, and that for which this is unnecessary. Accordingly, different coefficients are used for them - for example, for living rooms this is 100, and for technical rooms - 50-75.

Step 5. Based on the already determined calculation data, a specific model of the heating boiler and radiators is selected.

It should be understood that the only advantage of this method thermal calculation heating system is speed and simplicity. However, the method has many disadvantages.

  1. Lack of consideration of the climate in the area where housing is being built - for Krasnodar, a heating system with a power of 100 W per each square meter will be clearly redundant. But for the Far North it may not be sufficient.
  2. Failure to take into account the height of the premises, the type of walls and floors from which they are built - all these characteristics seriously affect the level of possible heat losses and, consequently, the required power heating system for the home.
  3. The very method of calculating the heating system by power was originally developed for large industrial premises and apartment buildings. Therefore, it is not correct for an individual cottage.
  4. Lack of accounting for the number of windows and doors facing the street, and yet each of these objects is a kind of “cold bridge”.

So does it make sense to use a heating system calculation based on area? Yes, but only as preliminary estimates that allow us to get at least some idea of ​​the issue. To achieve better and more accurate results, you should turn to more complex techniques.

Let's imagine next way calculating the power of the heating system - it is also quite simple and understandable, but at the same time it has a higher accuracy of the final result. In this case, the basis for calculations is not the area of ​​the room, but its volume. In addition, the calculation takes into account the number of windows and doors in the building and the average level of frost outside. Let's imagine a small example of the application of this method - there is a house with a total area of ​​80 m2, the rooms in which have a height of 3 m. The building is located in the Moscow region. There are a total of 6 windows and 2 doors facing outside. The calculation of the power of the thermal system will look like this. "How to make , You can read in our article.”

Step 1. The volume of the building is determined. This can be the sum of each individual room or the total figure. In this case, the volume is calculated as follows - 80 * 3 = 240 m 3.

Step 2. The number of windows and the number of doors facing the street are counted. Let's take the data from the example - 6 and 2, respectively.

Step 3. A coefficient is determined depending on the area in which the house is located and how severe the frost is there.

Table. Values ​​of regional coefficients for calculating heating power by volume.

Since the example is about a house built in the Moscow region, the regional coefficient will have a value of 1.2.

Step 4. For detached private cottages, the value of the volume of the building determined in the first operation is multiplied by 60. We do the calculation - 240 * 60 = 14,400.

Step 5. Then the calculation result of the previous step is multiplied by the regional coefficient: 14,400 * 1.2 = 17,280.

Step 6. The number of windows in the house is multiplied by 100, the number of doors facing outside is multiplied by 200. The results are summed up. The calculations in the example look like this – 6*100 + 2*200 = 1000.

Step 7 The numbers obtained from the fifth and sixth steps are summed up: 17,280 + 1000 = 18,280 W. This is the power of the heating system required to maintain the optimal temperature in the building under the conditions specified above.

It is worth understanding that the calculation of the heating system by volume is also not absolutely accurate - the calculations do not pay attention to the material of the walls and floor of the building and their thermal insulation properties. Also, no allowance is made for natural ventilation, which is inherent in any home.