The project of the co-opstage- bargaining refrigerator with a conditional capacity of 1150 tons.

Contents

Summary

Maintaining

1 Feasibility study

2 Literary Overview

3 Chamber capacity calculation, refrigerator layout

4 Selection of railing structure. Calculation of thermal insulation thickness

5 Calculation of heat inflows

6 Drawing up the functional diagram of the refrigeration unit

7 Equipment calculation and selection

8 Layout of the engine room

9 Refrigeration Automation

10 Heat-air shutter

11 Occupational safety

12 Calculation of economic effect

Conclusion

List of used temperature

Applications

Introduction

The refrigeration unit is set of the machines, devices, devices and constructions intended for production and application of artificial cold. Proceeding from this definition the refrigeration unit besides the basic elements which are a part of the refrigerator and necessary for implementation of the return thermodynamic cycle includes still the devices, devices, pipelines and constructions necessary for realization of technological processes at low temperatures.

Refrigeration plants are increasingly used in many industries. In the food industry, artificial cooling ensures the long-term preservation of high quality perishable products; and it is precisely due to the insufficient use of cold in the world that up to 40% of food production is lost.

The application of cold in food plants is based on the fact that biological and other processes take place at low temperatures, which is significantly different from how they are carried out under normal conditions. Most of these processes slow down at low temperatures, and some of them (for example, the life of certain species of bacteria) stop.

The main purpose of the refrigeration enterprise in the food industry is to create conditions that ensure the safety and high quality of perishable products of animal and plant origin. This task can be successfully solved by creating a continuous refrigeration chain, that is, a set of technical means that ensure the continuous impact of low temperatures on perishable products from the moment of their production (or production) to their consumption.

8 Layout of the engine room

The equipment of refrigeration units providing centralized refrigeration supply is located mainly in one room, called the engine room. Sometimes the machines are located in another room, called the equipment room, which may be adjacent to the engine room or be at some distance; for example, if the object to be cooled is located at a considerable distance from the engine room, then in order to reduce the diameter of the suction pipeline, circulation receivers with pumps are installed next to the object in a separate room - the equipment room [2, c.311].

The engine room plan and the section of the engine room are shown on sheets DP 36.20.01.125.03.01 and DP 36.20.01.125.03.02 of the graphic part of the diploma project, respectively.

The engine room (equipment room) shall be located as close to the cooled objects as possible and meet certain requirements depending on the properties of the refrigerant and coolant - toxicity, flammability and explosion hazard. The most stringent requirements apply to the premises of the ammonia refrigeration unit. So, the engine room of the ammonia refrigeration unit can be located in a separate building, in an extension to the refrigerator building or a one-story production building. It can be built into the refrigerator or into a one-story production building, from the premises of which it must be separated by fire walls that do not have openings. Above the engine room there may be a hardware room, but not a room with permanent workplaces, household and administrative.

The engine room (equipment room) must have at least two exits, as far as possible from each other, one must be directly outside, and the second is possible through the air lock with air pressure to the control room (if it has an exit to the outside) or to the corridor of utility rooms of the compressor shop, having an exit to the outside. The soundproofed room of the control panel for duty personnel, adjacent to the engine room, is equipped with an opening with sealed glazing with an area of ​ ​ not more than 3 m2 in the wall separating them. Excess air pressure is maintained in the room of the panel, which prevents air from entering it from the engine room. The total length of the path along the passages from any point of the engine (hardware) compartment to the door should be no more than 30 m. The equipment compartment adjacent to the engine compartment should have (in addition to the last exit) more exit.

The engine room is usually combined with auxiliary rooms providing the operation of the refrigeration unit and sanitary conditions for the compressor shop personnel. These rooms, separated by a non-burning wall, have an exit through a separate corridor connected by a door to the machine (equipment) compartment through a tambour lock and having an exit to the outside. In the engine room, there may be a power supply unit of the workshop, separated by a non-combustible wall; rooms for transformers, electrical switchgears and electrical switchboard shall have an outlet directly outside.

Construction dimensions of a single-span building (additions) in plan: column spacing 6 m and span 12 m (sometimes 18 m). the height of the engine room to the bottom of the supporting structures should be at least 4.8 m, and the hardware - at least 3.6 m.

Enclosing structures of the machine (hardware) compartment building shall have easily throwable elements (windows, doors, etc.) with a total area of at least 0.05 m2 per 1 m3 of compartment. Window bindings shall be glazed with ordinary window glass and the height of the window sills shall not exceed 1.2 m. Doors shall open towards the exit. The floor elevation of the engine (hardware) compartment and the premises communicating with it through the corridor shall not be lower than the level of the adjacent area. If this elevation is higher than the territory level, a platform with stages is performed at the exit from the compartment.

When placing refrigeration equipment in a container-type room (i.e. in a room, the mass, overall dimensions and the frame of which allow it to be transported by road and rail), its height from the floor to the bottom of the protruding parts of the equipment and pipelines above the passage and on the escape route must be at least 2 m.

When placing refrigeration plant equipment and process pipelines, it is necessary: to reduce the area, volume of rooms, length of pipelines as much as possible, while ensuring the conditions for safe installation, maintenance and repair of equipment and pipelines; provide for the possibility of expansion of the plant. The reduction of the area and volume of rooms for refrigeration equipment is achieved by its rational placement taking into account the possibility of equipment operation in the open air, the minimum size of passages between projecting parts of the equipment, and also between them and elements of the building, established by safety rules. The width of the main passage or distance from the control station to the projecting parts of the unit shall be at least 1.5 m; width of passage between projecting parts of units is not less than 1 m; width of non-main passage between smooth wall and apparatus (unit) must be not less than 0.8 m; the distance from the inner column to the projecting parts of the equipment is allowed to be 0.7 m with other passages of the required width. Some devices can be installed close to the wall, if this does not prevent their maintenance and repair.

The equipment room of the container type of ammonia refrigeration unit is not designed for the constant presence of maintenance personnel, therefore, in them the width of the main passage should be at least 0.8 m with a passage length of not more than 5 m; the width of the minor passage between the smooth wall and the equipment shall not be less than 0.6 m.

The equipment of ammonia refrigeration plants is usually placed as follows: in the engine and equipment rooms - compressor units, horizontal shell and tube condensers, protective, circulation, compound and drain receivers, intermediate vessels, pumps, central distribution (control) station; at the open area (in climatic zones with air temperature in winter not lower than minus 400C) near the engine (equipment) compartment - condensers, linear receivers, central oil separators, oil fitters, cooling towers; in cooled rooms - batteries and air coolers; in production premises - ice generators, frosting machines, freezers. Water pumps of the cooling water supply system are placed in the engine (equipment) room, and in large installations - in the pump room together with fire and utility pumps in the unit with condensers and cooling towers. The distribution headers of the chambers can be located not only in the engine room, but also in single-storey refrigerators on the mezzanine in the cargo corridors, in multi-storey on each floor in special heated rooms.

When determining the area necessary for the arrangement of insulated devices, it is necessary to increase the corresponding dimensions of the device by the thickness of the heat insulation layer and the size of the indentation from the walls, which allows performing insulation work. A reduction in the area of the machine (hardware) compartment can be achieved as a result of a more rational use of the space. Some devices can be installed on top of each other in several tiers. The vertical mutual position of circulation and compound receivers with pumps depends on the value of the cavitation reserve of pumps, which generally varies from 0.5 to 4 m. Therefore, in order to reduce the required height of the room, especially when using vertical vessels, in machine In the (apparatus) compartment, a pit is arranged to accommodate pumps, liquid risers of circulation receivers, an auxiliary receiver for collecting liquid from suction and discharge pipelines of compressors, from devices and cooling devices. The pit has a fence at least 1.1 m high and two stairs.

In accordance with safety regulations, a platform with a fence and a staircase shall be arranged to service equipment and fittings at a height of 1.8 m from the floor. If you have more than one piece of equipment nearby, you will have a shared entresole (often on two levels) with a fence and stairs.

Significantly reduces the construction area of ​ ​ the machine (hardware) room and improves the safety of the operation of the refrigeration unit by placing part of the equipment on an open area near the engine room .

In addition to the devices mentioned earlier, screw and centrifugal compressor units can be installed in the open air under a canopy, if such an opportunity is provided for their manufacture. In order to reduce the diameter and length of pipelines, open areas shall be as close as possible to the machine room; Note here that territory development nature, purpose of adjacent structures, direction of prevailing winds in winter and summer, possible consequences of accidents and equipment characteristics are taken into account. Cooling towers, evaporation condensers and air condensers shall be blown by wind so as not to create a zone with increased humidity and temperature, while the wind shall not interfere with the air flow generated by the fans. The entrainment of water drops should not affect the condition of nearby objects. When placing several units of cooling towers, evaporation and air condensers, the distance between the devices should be at least 2-3 m; The devices are staggered at a distance of at least 2 m. The open platform is better placed on the side of the blind wall in order to increase the level of safety when operating on toxic and fire hazardous refrigerant.

Cooling towers, evaporation and air condensers can be placed on the roof of the machine (equipment) or pump room [2, p.312].

The reduction of the area of the engine room is possible as a result of the selection of the supporting equipment and the scheme of the refrigeration unit (aggregated equipment, screw compressor units with the supply of refrigerant steam at intermediate pressure, compound refrigeration unit).

For equipment maintenance it is necessary to provide access to the serviced places and sufficient passages. Equipment requiring continuous or periodic monitoring shall be easily accessible and shall not be installed at a height that makes maintenance difficult. It is necessary to ensure the necessary natural illumination of elements requiring more careful maintenance. Instrumentation shall also be illuminated well enough. For ease of installation and repair of the equipment it is necessary to take into account the possibility of its disassembly, therefore, there should be a place sufficient to remove the longest part from the compressor or apparatus and neither adjacent equipment nor building structures of the building should interfere with this. The tubes must be positioned so that from the side of one of the caps it is possible to remove and replace any of the tubes, as well as periodically clean the tubes. If the shell-and-tube apparatus is installed against the window, then both cleaning of pipes and their replacement are possible through it. There should be free platforms near the machines and devices, sufficient to accommodate individual large parts during installation or removed during repair. Such mounting areas may be common to the set group.

To allow expansion of the refrigerator (production) or prospective construction of a new cold consumer in the engine (equipment) room, a reserve area is provided for the installation of equipment, and free space is provided on the general plan. Thus, the selected equipment is placed in accordance with the layout of the installation in the room and in the open area, while complying with the requirements of safety regulations and ensuring the possibility of maintenance and repair, expansion of the installation, as well as achieving economy. As a result, the required dimensions of the spaces and the open area are found. The area of ​ ​ utility premises is determined by the number of personnel of the compressor workshop, administrative - by the number and cooling capacity of compressor units, the power supply unit - by the electrical capacity of the equipment. Then, the building is built, taking into account the size of standard building structure elements.

Meeting all the requirements in the design of engine rooms is not an easy task, especially since by placing equipment the dimensions of the rooms themselves are found. When performing variant calculations of indicators of refrigeration plants, the required construction area Fstr for equipment placement is found using the values ​ ​ of the area fi occupied by the eighth unit element and coefficients bi, which take into account the additional area, including for auxiliary household premises. Then the required construction area to accommodate the refrigeration unit Fstr=∑ (fibi).

The best solution is identified by comparing several equipment locations. You can determine the best option using the geometric modeling method. The best planning solution is the basis for the drawings and diagrams of the refrigeration unit [2, p.317].