Exchange rate heating of residential building

Contents

Source Data

Selection of external and internal air parameters

Calculation of thermal losses of the building

Heat loss of the building by floors

Heat load and flow rate in risers

Heating System Selection and Design

Thermal calculation of heating devices

Hydraulic calculation of heating system

Material and Equipment Specification

List of literature

Heating System Selection and Design

Heating systems of residential and civil buildings shall ensure uniform heating of the air of heated rooms during the entire heating period, the ability to regulate productivity, permissible noise level, convenience in operation and repair, fire safety, and should not violate the interior of buildings. When designing heating systems, it is necessary to ensure that useless heat losses (through external enclosing structures behind heating devices and pipelines laid in non-heated rooms, etc.) are minimal. Heating systems shall have minimum metal consumption.

Water heating systems come with natural and artificial coolant circulation. In systems with natural circulation, the movement of water occurs due to the difference in densities of cooled and hot water. In systems with artificial circulation, the driver is a mechanical pump or a jet pump (elevator).

If the coolant sequentially passes through heating devices, the heating system is called single-tube, and when the devices are connected in parallel, it is called double-tube.

Vertical single-tube heating systems with lower wiring and U-shaped or T-shaped risers are recommended for a building with a height of three floors or more with attic coatings. They are also useful in buildings with attics using heating devices, the heat transfer of which does not depend on the direction of water movement in them (for example, convectors). [3, page 64.67]

Vertical single-tube heating systems are recommended to be designed with a dead end circuit of coolant movement in the main lines.

With artificial circulation, the heating system is characterized by significant initial and operational disregard. Cranes of increased hydraulic resistance proposed for reduction of underregulation are manufactured in limited quantity by industry. Heating systems with natural circulation are free from operational deregulation, but their range should not exceed 30 m horizontally.

Pipelines of heating systems are laid open, with the exception of pipelines of water heating systems with heating elements and risers built into the structure of buildings. It is recommended to place heating system risers in corners formed by external enclosing structures.

Main pipelines are laid in basements, technical floors, attics, underground or (in their absence) in channels under the floor of the first floor or open, above the floor. When laying pipelines in channels, it is possible to access pipelines by means of a removable floor frieze. Piping of main pipelines is arranged as per-stage for possibility of heating system adjustment.

Sleeves with annular clearance of 1-5 mm between inner surface of sleeve and pipeline are installed in points of intersection of floors, walls and partitions by pipelines. Gap is filled with non-combustible heat-insulating material. The edges of the casings are located 21-30 mm above the surface of the clean floor and at the same level as the surface of the walls, ceilings and partitions. When pipelines cross fire-fighting walls, places of passage are tightly sealed and they serve as fixed supports. Free heat extension of pipes is provided on both sides of walls. Risers of single-tube heating systems with flow heating devices and with displaced closing sections are allowed to be laid through non-combustible ceilings without installation of sleeves.

Riser design shall ensure unification of units and parts. To industrialize the procurement process and reduce the labor intensity of installation work, it is recommended to design single-tube risers with one-sided connection of heating devices and connections of the same length (l500 mm). The riser of the single-tube system is placed at a distance of 150 mm from the slope of the window opening, and not along the axis of the spacer, as with double-sided pipelines and in double-tube heating systems.

In corner rooms, risers are recommended to be placed in the corners of external walls to avoid moisture condensation on the internal surface.

The type of riser is selected depending on the architectural and planning solutions, the routing of the mains and the requirements for the thermal mode of the building premises.

Flow risers without cranes for regulating heat removal of heating devices are used in stairwell rooms and where no thermal regulation is required.

Vertical bifilar risers should be used in multi-storey buildings to ensure hydraulic and thermal stability. For heating residential and public buildings, as a rule, adjustable and flow-controlled risers, and risers with axial and offset closing sections are recommended.

The diameter of risers of single-tube heating systems is recommended to be taken constant along the entire length and equal to 15 or 21 mm. Risers with a diameter of 25 mm are recommended only if it is impossible to link head losses in them in other ways. It is allowed to use composite risers from pipelines of not more than two diameters; the riser must have only one transition from one diameter to another .

Vertical sections of single-tube risers are laid at a distance of 150 ± 50 mm from the window slope .

For the possibility of the system emptying, the main pipelines are laid with a slope, the value of which should be taken at least 0.002.

Main pipelines with a diameter of more than 50mm and distribution lines of horizontal heating systems, regardless of diameter, can be laid without a slope; Note here that water flow rate in pipelines must be at least 0.25 m/s.

Air from heating systems is removed at higher points. In heating systems with lower wiring, air is removed through air valves on upper heating devices or through an air collector on air lines, and in systems with upper wiring and natural circulation of coolant - through an expansion tank.

Heating devices are recommended to be located mainly under the light openings. They are placed under windows so that vertical axes of window openings and instruments coincide. Heating devices should not be placed in compartments of tombs having external doors.

Heating of staircases is provided using recirculating air heaters from convectors, ribbed pipes or heaters, as well as panel radiators located in the lower part of staircases for buildings up to 12 floors high. When heating systems are connected to heat networks with the temperature of the coolant - water exceeding the permissible one for the accepted heating system, staircase heaters are arranged, as a rule, pre-connected with respect to the main heating system. At a height of less than 2.2m from the level of the floor, platforms or steps of stairways, heating devices in staircases are arranged so that they do not reduce the width of the marches and intermediate platforms required by fire standards and do not form protrusions from the plane of the walls. [3, c.70]

If there are several heating devices in the room, the control valves are installed for a part of them so that the heat transfer of the controlled devices is at least 50% of the total heat transfer of the devices in this room.

If the coolant temperature in the supply line is more than 100 ° С, valves are installed on the risers instead of through cranes and drain cranes instead of tees with plugs. In buildings with a height of 9 floors and more, drain cranes for emptying risers and valves are installed regardless of the temperature of the coolant. The distance from pipelines lines to shut-off valves installed on risers or branches of pipelines shall be not more than 121mm.

When choosing the type of heating devices, first of all, take into account the pressure in the system, the quality of the coolant, as well as the composition of the air environment of the rooms.

It also takes into account the purpose and architectural - technological layout of the building, the peculiarities of the thermal regime of the premises, the places and duration of people staying on them.

With increased sanitary hygiene, as well as fire and explosion protection requirements, devices with a smooth surface are chosen - concrete or steel panel radiators and smooth tube devices.

With a long stay of people in ordinary conditions, convective radiation devices are used (no more than two types of devices for the entire building or structure). [2, c.42]

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