Residential building heating system

Contents

INTRODUCTION

THEORETICAL PART

Heating systems

DESIGN PART

1. Heat Engineering Calculation of External Enclosures

1.1. Selection of design parameters of external and internal air

1.2. Determination of heat transfer resistances of external enclosures

1.2.1.Define the heat transfer resistance of the outer wall

1.2.2. Determination of heat transfer resistance of the attic floor

1.2.3. Determination of heat transfer resistance of the floor above the non-heated basement

2. Heating system thermal capacity

2.1. Determination of design heat losses through external fences

2.2. Determination of total heat losses taking into account infiltration and heat inputs into the room

2.3. Specific heating characteristics of the building

3. Heating System Design

4. Hydraulic calculation of heating system

5. Heating Fixtures Calculation

CONCLUSION

Introduction

The purpose of the course work is to design a single-tube vertical water heating system to maintain the necessary thermal conditions of the building. During the work, it is necessary to carry out thermal calculation of fences, hydraulic calculation of the heating system, calculation of heating devices, determine the thermal power of the heating system and select the equipment of the heating station.

The task for the course work provides the necessary initial data: the characteristics of the building, its purpose, the type of heating system, the type of control valves, the design temperatures of the network water in the thermal network, the design temperatures of the water in the heating system of the building.

Tasks that need to be addressed in this work:

Design of the building heating system.

Calculates heating fixtures.

Creates a typical floor plan, basement plan, and axonometric diagram.

The graphic part assumes:

A standard floor plan for a 1:100 scale building that marks the location of the risers;

basement plan of the building, also made on a scale of 1:100, with indication of risers and highways, heat point;

a 1:100 scale axonometric diagram.

Theoretical part

Heating systems.

Heating is called artificial heating of the building premises with compensation for heat losses to maintain the temperature in them at a given level, determined by the conditions of thermal comfort for the people in need and the requirements of the ongoing technological process.

A heating system is a set of structural elements with connections between them, designed to receive, transfer and transfer the necessary amount of heat to heated rooms, buildings, structures.

Heating systems are classified according to the following characteristics:

1. By type of coolant used:

A) water;

B) steam;

C) air;

D) furnace;

E) radiation;

E) electric.

2. According to the method of coolant movement

Water heating systems:

A) with forced coercion;

B) with natural motivation.

Steam heating systems:

A) low pressure;

B) high pressure;

C) with gravity condensate return;

D) with condensate tank and pump.

3. At the location of the heat source:

A) central;

B) local.

The designed heating systems shall meet sanitary and hygienic requirements, ensuring:

1. Microclimate parameters, air purity in the serviced area of the premises within the limits of optimal or permissible standards;

2. Microclimate parameters, air cleanliness in the working area of production, laboratory and storage rooms in buildings of any purpose within the limits of optimal or permissible standards;

3. Permissible noise and vibration levels from the operation of systems and equipment.

In addition, heating systems must meet the requirements of reliability, fire, explosion safety and energy efficiency.

When choosing a heating system, type and parameters of the coolant, as well as types of heating devices, it is necessary to take into account the thermal inertia of the enclosing structures, the nature and purpose of buildings and structures.

In course operation we accept the most economical single-tube vertical system of water heating with n-shaped risers with lower wiring of hot and return lines with displaced closing sections and adjusting valves on the reverse supply to the device.

A single-tube water heating system is a heating plant, the risers or branches of which consist of one pipe connecting in series a number of heating devices.

Single-tube vertical flow heating systems with offset closing sections and three-way cranes to control the heat transfer of heating devices are now widespread. Single-tube water heating systems do not have reverse risers. The principle of this system is as follows. Hot water from the boiler is supplied to the risers via the main riser and supply line. At the points of connection of heating devices to the riser, the water flow is distributed: part of the water passes in transit along the riser through the jumper, and part flows into the heating device.

The water, having cooled in the heating device of the upper floor, leaves it and is mixed with hotter water passing through the bridge. Mixed water flows through the riser to the heating device of the underlying floor, where the water flow is again distributed, that is, part of the water enters the device, and part passes through the bridge. Such water movement is repeated on each floor in the course of coolant movement.

Thus, in this heating scheme, water is supplied to each downstream device at a lower temperature.

Heat removal of heating devices in such systems is controlled by turning the plug of a three-way crane within 90 °. Thus, the jumper (all water passes through the instrument) or the instrument (all water passes through the jumper) can be turned off. At the intermediate position of the valve plug, part of the water will go through the device, and part - through the jumper. If double control valves are installed on the devices, the diameter of the closing section should be one size less than the diameter of the riser.

Displacement of the closing section from the riser axis provides better than the axial closing section supply of water from the riser to the heating devices and compensating for linear extensions of the riser by taps on the supply lines to the devices, which is important for the arrangement of heating systems in buildings of increased floor size.

The vertical single-tube water heating system with upper wiring was widespread in the beginning. 50s. It was carried out with two-way, and then one-way connection of heating devices to risers.

During the lower wiring, hot water from the heating boiler enters the main pipe of hot water from below, from the basement, and then is distributed over risers and radiators.

Supply and return lines are located in the basement room. There is no exit of pipelines to the attic, due to this, heat losses are reduced, and maintenance of the heating system is simplified. Air descends through air cranes installed on heating devices of the upper floor. The supply risers in such a heating system are divided into lifting and lowering. Lifting riser is laid from supply main line to upper floor, where it passes into lowering riser, which in basement is connected to return main line. Adjustment of heat removal of heating devices is carried out by cranes installed on all heating devices.

Single-tube systems with lower wiring are used in attic-free buildings with technical underground and basements, as well as, if necessary, floor-by-floor actuation of the system during the construction of the building.

The heating system with U-shaped risers can be activated floor-by-floor (with temporary jumpers) during installation, and this feature of the system is used in winter when performing internal finishing work in a multi-storey building under construction.

Common U-riser scheme for 3-storey building with deaerated water heat supply. In the lower floor, the flow of water through heating devices is shown, in the middle floor there are nodes with offset closing sections, and in the upper floor there are flow-controlled nodes with three-way cranes. Air cranes are installed on heating devices of upper floor.

The U-shaped single-tube riser scheme combines the advantages of water movement in the heating device from top to bottom and the lower laying of both highways. At the same time, the ascending (idle) part of the riser can be frozen into the building structures of the building and turned into an additional panel flow heating device.

The main advantage of single-tube systems is their lower cost than double-tube systems, so they were most used in multi-storey buildings, as well as in rooms with a large area. Compared to double-tube, single-tube water heating systems have a more aesthetic appearance, lower metal consumption of the system, simpler piping assemblies, which simplifies their procurement and installation of systems, better thermal and hydraulic stability.

Vertical U-shaped single-tube risers are used in attic multi-storey (three to seven floors) buildings with a technical underground or basement. During the construction of the building in winter, the heating system with U-shaped risers can be activated gradually - floor by floor as internal finishing work begins.

Heating System Design

Dead-end single-tube vertical heating systems, especially systems with lower routing of main pipelines, have become widespread. These systems have a number of advantages and are well established in installation and operation. The fulfillment of a number of conditions during the development of systems leads to high processability, good controllability and the possibility of automating their hydraulic and thermal conditions.

Systems design begins with the placement of risers and heating devices on floor plans. Risers are installed at a distance of 150 + 50 mm from the slopes of window openings, and heating devices at a distance of 500 mm from the risers. Heat station is placed in basement of central part of buildings.

The single-tube system with lower wiring consists of U-shaped risers connected by lower ends to hot and reverse water lines. Lifting sections of U-shaped risers of radiator systems are laid in rooms with smaller heat losses, which allows reducing the surface of radiators. The heating system usually consists of several separate branches connected to the common distribution line, which allows you to adjust the heat transfer of different parts of the system and disconnect them if necessary repair work. Air removal in the system with lower mains routing is carried out through cranes installed on heating devices of the upper floors. At the lower points of the dilution pipelines and on the riser, water lowering devices are installed.

For shutdown of struts and descent of water from them on lifting and lowering sites in places of accession of struts to highways pith cranes, gates, T-connectors are installed. In order to ensure air discharge and water lowering, the hot and return water main pipeline slopes shall be at least 0.002. The slope of the lines is usually directed towards the heat point.

Heating devices are placed in niches under windows, if this is not possible - at external or internal walls. In corner rooms, devices are placed along both external walls, in staircases heating devices are installed under the staircase march of the first floor, they are connected to individual risers of the heating system.

U-shaped risers of heating system have lifting and lowering sections. Lifting section is laid over rooms with lower heat loads. Heating of bathrooms is carried out by a towel dryer, which is connected to the circulation riser of the hot water supply system. Control valves are installed on supply lines to accumulating devices for control of heat transfer.

In residential buildings, cast iron and steel radiators, convectors and, when substantiated, heating panels are used. In this course design, it is recommended to use cast iron radiators.

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