Centralized hot water supply of residential neighbourhood

Contents

1. Introduction

2. Selection of Hot Water Heat Exchanger Connection Diagram

3. Determination of the ambient temperature corresponding to the point

fracture of temperature plot

4. Battery Tank Capacity Determination

5. Calculation of hot water heat exchangers

6. Calculation of heat release control by combined load

7. Determination of hot water flow rates per second

8. Hydraulic calculation of hot water supply pipelines

9. Hot Water Circulation

10. Hydraulic calculation of circulation pipelines

11. Hydraulic calculation of water heating plant

12. Selection of water meter for hot water supply system

13. Required head of cold water supply at input to CTP

14. Selection of circulation pumps

Literature

Introduction

In this course work on the topic: "Centralized hot water supply of a residential microdistrict," a hot water supply system for a group of the same type of residential buildings is being developed. Water preparation for the system is carried out at the price center of the CTP.

Hot water supply is designed to satisfy the hygienic (washing, bathing) and household (washing, washing dishes, etc.) needs of the population in water with an elevated (up to 75 ° C) temperature. Such water, called "household," is supplied with buildings with housing (residential buildings, dormitories, hotels), most public and communal buildings (hospitals, clinics, baths, laundry rooms, children's institutions, catering enterprises, etc.), as well as industrial buildings and structures with technological and hygienic (in households) consumption of hot water.

Hot water supply was widely developed in our country during the years of Soviet power as a result of concern for improving the welfare of workers. Whereas in 19101912, even in a city such as Moscow, with a population of 1.1 million people, only about 2% of the total number of inhabitants could use baths, now providing hot water is a mandatory component of modern construction of residential and public, as well as industrial buildings and structures. Also, work is underway to improve the quality of hot water, especially to save energy resources.

In the simplest form, the local hot water supply system consists of a preheating unit and pipelines for transporting hot water to water separation devices. There are centralized and decentralized systems. In centralized buildings, one heating plant serves at least one building, and in many cases even several buildings within the same quarter (microdistrict) or village. In decentralized systems, hot water is prepared near water collection devices (at the point of consumption) and is carried out by small heat generators: gas heaters, wood columns, electric heaters, etc.

In this course work on the topic: "Centralized hot water supply of a residential microdistrict," a hot water supply system for a group of the same type of residential buildings is being developed. Water preparation for the system is carried out at the price center of the CTP.

The following issues are solved in the work - constructive development of the hot water supply system; quarterly heat lines and central heat point; arrangement of equipment and fittings; determination of estimated heat and hot water flow rates, construction of heat flow charts; Determination of the net flow rates of the network water; hydraulic calculation of supply and circulation heat lines; selection of heat station equipment, calculation of accumulator tank capacity based on integral graph.

Hot Water System Description

Hot water supplied to consumers shall comply with GOST 287473 "Drinking water."

Water temperature after heaters is determined by sanitary and hygienic requirements. The lower limit is the so-called "pasteurization temperature" equal to 60 ° C, at which most pathogenic bacteria die; the upper limit is limited to 75 ° C to avoid burns by consumers .

The standards also limit the temperature of hot water supplied to washbasin and shower mixers in buildings where social welfare institutions, general education schools, preschool institutions, orphanages and other children's institutions are located, as well as in buildings of medical and preventive institutions (not higher than 37 ° C).

The easiest and cheapest at the original cost are circulation-free (dead end) systems consisting of only one supply pipeline. The main disadvantage of such systems is the cooling of water in pipelines during a break in water intake or its small value. Opening the crane after a water intake break, the consumer receives cooled water and drains it to the sewer to the desired temperature. Such drains lead to overloading of the sewage system and useless losses of water and heat. For this reason, circulation-free systems are arranged only in cases of uninterrupted intake of hot water and with a short network length. In all other cases, especially where non-intermittent provision of hot water to consumers is required (residential buildings, hospitals, clinics, etc.), more complex circulation systems are arranged. In such systems, in the absence of water discharge, the water in the pipes does not stop, but is continuous, moves through the preheater, thereby providing a given temperature near the points of water discharge. Depending on the purpose of the systems, the circulation of water in them can be carried out continuously during the day or periodically before the start of long-term water discharge.

By the location of the supply (breeding) highway inside the house, systems with upper and lower wiring are distinguished. Upper wiring is most often used when installing open (upper) battery tanks and if there is an upper technical floor or attic in the building. In the presence of basements, lower wiring is preferable as more convenient for operational maintenance of the system.

In this work, the hot water supply system is designed for circulation, the circulation main heat supply is carried out in the attic. The risers are located near the towel dryers and have little effect on the interior of the premises. One hundred tanks are combined into circulation units and connected to the collection circulation pipeline through a common circulation riser. 1 sectional unit and 1 precast circulation riser are designed. The sectional node combines 8 hundred-yaks.

The supply main heat pipe is designed with lower wiring (there is a basement). Supply and circulation main heat lines are fixed on brackets to load-bearing enclosing structures or by means of sub-scales to ceiling or floor.

For the convenience of linking the buildings with the general building plan, the thermal conductors are located in the middle of the building section.

Shut-off valves are provided on cold and hot water pipelines at water heaters; on branches of pipelines to section units; and at building entrances. Check valves are installed at water heaters on circulation heat lines and on pipelines supplying cold water.

Hot water parameters are monitored by thermometers and pressure gauges. Pressure gauges are installed at water heater outlet, before and after circulation pump. Thermometers are installed before and after water heater and on circulation heat line before circulation pump.

To account for water flow, water flow meters are provided, which are installed in closed heat supply systems on the cold water pipeline before the water heater.

Group hot water heaters, usually located in separate buildings, are called central heat centers (CTP).

For the microdistrict, CTP has been designed and heat network routes have been laid from the main chamber (1) to the CTP and from the CTP to each building.