Heating, ventilation

Contents

Paper

Introduction

1 Thermal engineering calculation of enclosing structures

1.1 Determination of heating system thermal power

1.2 Determination of main and additional losses through enclosing structures of premises

1.3 Determination of heat flow rate for heating of infiltrating outdoor air through enclosing structures of rooms under thermal pressure

1.4 Determination of heat consumption for heating of infiltrating outdoor air through enclosing structures of rooms with natural exhaust ventilation..... 13 1.5 Household heat emissions

1.6 Design of results of calculation of heating system thermal power... 14 1.7 Thermal engineering evaluation of architectural and structural solution of the building

2 Heating system design

3 Hydraulic calculation of heating system

3.1 Determination of heat losses

3.2 Determination of circulation pressure

3.3 Determination of approximate friction pressure losses

3.4 Determination of coolant flow rate in the design area

3.5 Determination of pipe diameter, water flow rate and friction pressure losses in the design area

3.6 Determination of pressure losses on local resistances

3.7 Determination of total pressure losses

4 Determination of the number of radiator sections used as heating devices

5 Calculation and selection of elevator

6 Selection of residential building ventilation system

6.1 Determination of aerodynamic pressure

6.2 Determination of air speed

6.3 Determination of Friction Pressure Loss

6.4 Determination of pressure losses on local resistances

6.5 Determination of total pressure losses

6.6 Calculation of louver screens

6.7 Design of aerodynamic calculation results

7. Material and Equipment Specification

Conclusion

List of sources used

Introduction

Today, systems for ensuring the specified climatic conditions in the premises are integral technological elements of modern buildings, and they account for a significant part of capital investments and operating costs. Knowledge of the basics of heat engineering and ventilation makes it possible to plan and carry out measures aimed at saving fuel and energy resources, protecting the environment, and improving the efficiency of equipment.

Heating - artificial heating of rooms in the cold period of the year in order to compensate for heat loss in them and maintain at a given level the temperature that meets the conditions of thermal comfort, and sometimes the requirements of the technological process.

Heating systems, being part of heated buildings, must meet sanitary, technical and economic, architectural, installation and operational requirements.

Sanitary and hygienic requirements are to ensure the specified air temperature in the heated room, and at the same time, excluding the possibility of burns of a person from heating devices, as well as accumulation and burning of dust on them.

The technical and economic requirements are to optimize the costs of construction and operation of the heating system.

Architectural and construction requirements should provide for the interconnection of all elements of the heating system with the construction and architectural and planning solutions of the premises.

Installation requirements provide compliance with the modern level of mechanization of installation works.

Ventilation - controlled air exchange in the room, as well as the devices that create it. Ventilation is designed to ensure the necessary purity, temperature, humidity and mobility of air. These requirements are determined by hygienic standards: the presence of harmful substances in the air (gases, vapors, dust) is limited by the maximum permissible (harmless to human health) concentrations, and the temperature, humidity and mobility of the air are set depending on the conditions necessary for the most favorable human well-being.

Selection of residential building ventilation system

Ventilation of rooms should be provided to ensure normal meteorological conditions in these rooms. Air removal from rooms by ventilation systems should be provided from areas where air is most polluted or has the highest temperature or enthalpy. Intake holes for air removal by general exhaust ventilation systems, from the upper area of ​ ​ the room should be placed under the ceiling or coating, but not less than two meters from the floor to the bottom of the holes to remove excess heat, moisture and harmful gases, as well as a minimum of 0.2 m from the ceiling plane to the louver axis.

The project provides ventilation with natural motivation. The natural ventilation system has louver grates covering intake holes for contaminated air. The system is made through with ventilation channels, each of which communicates with atmospheric air.

In general, air removal on the exhaust with a natural impulse occurs according to the following scheme: contaminated air from the rooms enters the louver grille into the channel, rises up, reaches the prefabricated air ducts and exits through the shaft into the atmosphere. To increase the intensity of air exchange, a deflector can be installed at the shaft .

6.1 Determination of aerodynamic pressure

Aerodynamic pressure in exhaust system with natural impulse Pe, Pa is determined by formula 8.1 [2]:

Pe = h·g· (pH pB),

where h is the height of the air column received from the center of the exhaust hole to the mouth of the exhaust shaft , m;

g - acceleration of free fall, m/s2, g = 9.81 m/s2;

αn; ρв - density of external and internal air respectively, kg/m3, ρн; ρв - according to the P [2] application. At the same time temperature of external air it is necessary to accept +5 °C, and temperature of internal air on appendix A [2 ].

6.2 Determination of air speed

The air velocity, m/s, is determined by formula 8.2 [2];

υ = L /(3600·f),

where L - ventilation air flow rate (air exchange rate), m3/h,

f - channel or duct section area, m2.

The value f is defined depending on the counted ventilation system element from a condition of change of speed of the movement of air in the following intervals: in vertical channels, horizontal air ducts and combined channels - υ = 1,01,5 m/s; in the exhaust mine - υ = 1,52,0 m/s. Dimensions of rectangular and square channels should be taken according to Appendix P.

6.3 Determination of Friction Pressure Loss

Friction pressure losses Rtp, Pa are determined by formula 8.2 [2]:

Rtp = Rud· Lel· β,

where Rud - friction pressure loss on the linear length of the steel duct, Pa/m, is determined according to Appendix C, [2];

Lel - length of calculated element of ventilation system, m;

β - roughness coefficient, according to Appendix T, [2].

Conclusion

The design of heat supply and ventilation systems for a residential 3-storey, 12-apartment building has been completed. The graphic part shows all the graphic diagrams of ventilation and heating elements. On the basis of the calculations given in the explanatory note, the necessary data for the project were obtained:

1) Heating system thermal power Qpotr = 83758 W

2) Dead end double-tube heating system with lower supply line wiring has been designed, heating devices - cast iron radiators MS14098.

3) Number of radiator section - 556 sections.

4) The elevator of structure No. 4 is accepted.

5) Full pressure losses - 990 Pa are determined.

6) The natural ventilation system is designed through, with ventilation channels. For kitchens, air exchange is taken as Lkuh = 90 m3/h, because the kitchen has 4x confectionery stoves, for bathrooms and baths L = 25 m3/h.

7) Louvers are accepted for installation: 100x150 - in the bathroom and bathroom, 150x250 - in kitchens.

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