Cold storage should build on convenient transportation, water, electricity supply reliable place, library site should have a good sanitary conditions, try to avoid the industrial and mining enterprises of the harmful gases, smoke, dust and other pollution sources from the hospital for infectious diseases. Meat, fish processing plant cold storage should be arranged in the city residential summer wind minimum frequency upper side, located near the origin or distribution of goods convenient place. Building usually consists of cold processing and cold storage building, cold processing auxiliary buildings, transport facilities, management and living space of building and room ice building etc.. Cold processing and cold storage building referred to as " cold ", including the temperature at 0℃cooling, the temperature of -23 ~ -30℃frozen room, at a temperature of -12 ~ -20 ℃cold storage room, and the temperature of -4 ~ -10℃ice storage room temperature is 0-4 ℃precooling room ( row acid ). Cold storage layout should make a reasonable process, short route, do not cross, high, low temperature area clear, try to minimize the envelope area, column distribution neatly, and considering the expansion and repair convenience. The generally planar multilayer storage into square, often built dumbbell or single. Dumbbell type will be high-temperature storage and low-temperature storage is divided into two separate envelope structure, in the middle of the hall cohesion, good using effect. Single type in high, cold storage insulation wall between the floor and the ground to be spaced apart, doors and room temperature hall connected set, door air curtain, to prevent cold air from inside the library. The cold wall, ceiling, ground to lay low thermal conductivity material, such as rice husk, cork, asphalt, expanded perlite block such as insulation, are now more commonly used is moisture-proof plastic extruded board or polyurethane spray, also useful polyphenylene ( moisture resistance is not good ), to prevent the outside heat flux in library, increase the heat load. In order to prevent the outdoor water vapor to heat insulating layer permeability, also in the insulating layer of high temperature side laying the permeability barrier of the material, such as asphalt felt as a gas barrier polymer moisture-proof material, usually used at present.
Cold storage structure
Cold storage building from construction to start to equipment installation is usually performed at room temperature, structure system at room temperature; and the cold storage is put into use, the structure system in low temperature environment. Due to the large difference of temperature caused by the structural system deformation than ordinary building much larger, it is necessary to carry out the temperature stress calculation, in order to prevent " cold bridge ". Floor should take measures to prevent freezing, Keelung has caused damage to buildings. At the same time should choose antifreeze strong material, in order to enhance structure, freezing resistance durability.
Small refrigerator load-bearing structure is generally a beam structure, and large multilayer storage using cast-in-place reinforced concrete flat slab structure. In recent years, prefabricated beamless roof with lift slab construction method in the floor without beam frame structure was gradually extended. Cold storage enclosure wall structure design in addition to meet the strength and stability, but also maintain the adiabatic layer and the isolation layer of continuity, which accords with the requirement of building. Cold storage roof structure under the direct irradiation of the sun a long time, affected by weather, will produce the expansion or shrinkage deformation, should adopt the prefabricated, deform in component to adjust between, thereby reducing the total deformation. In order to prevent roof stretching to the wall to have adverse effects, can be in the roof structure and the wall between the sliding contact surface design.
Cold storage equipment
General cold storage by refrigeration, the gasification temperature is very low ( or liquid ammonia Freon ) as a coolant, the low pressure and mechanical control under conditions of evaporation, absorb the heat in the repository, so as to achieve the aim of cooling. The most commonly used is the compression type refrigerating machine, mainly composed of a compressor, a condenser, a throttle valve and the evaporation tube etc.. According to the evaporation tube device in a manner can be divided again direct cooling and indirect cooling two. Direct evaporation cooling will pipe installed in the refrigerated warehouse, liquid coolant through the throttle valve, direct absorption heat and cool in the warehouse. Indirect cooling is provided by a blower set storeroom in air to be drawn air cooling unit, air is circling in the cooling device of the evaporating pipe after heat absorption, and storage and cooling. Air cooling system has the advantages of rapid cooling, the temperature in the library is uniform, and can be produced in the process of storage of carbon dioxide and other harmful gases with a library.
Cold insulation
General storage and outside obvious temperature difference, need to adopt the insulating material to prevent heat transfer; current insulation materials polyurethane ( divided plate and spray at the scene two ), Extrusion board, foam board and other types, especially in the field of spraying polyurethane moldings by the best effect, low thermal conductivity and are connected into a whole without seam, with very high price advantage. Assembly of cold storage in recent years are also popular, because it has the advantages of short construction period, meet the health standards, detachable etc..
A cold, architectural features and requirements
Cold storage is mainly used in food processing and cold storage, it through artificial refrigeration, indoor maintain certain temperature. Cold storage walls, floor and ceiling are coated with a certain thickness of insulating material, to reduce the outside incoming heat. In order to reduce the absorption of the radiant energy of the sun, cold storage wall surfaces are generally painted white or light color. So cold storage construction and general industrial and civil construction, it has a unique structure.
Cold storage building to prevent water vapor diffusion and air permeability. Outdoor air intrusion not only increases the cold cold consumption, but also to shed into the water, moisture condensation from building structure particularly insulation moisture freezing damage, so to set the moisture-proof insulation layer, so that the cold storage building has good sealing property and moisture vapor resistance.
Effect of low temperature cold storage foundation, the soil moisture is easy to be blocked in. Because the soil is frozen after volume expansion, will cause the ground rupture and the entire building structure deformation, serious will make cold storage can not be used. Therefore, low temperature cold storage floor addition to a effective heat insulation layer, insulating layer also must be processed, to prevent the soil freezing.
The cold floors shall be piled up a lot of goods, but also pass a variety of transport loading and unloading equipment, flat top is also provided with a refrigeration equipment or pipeline. Therefore, its structure should be strong and has large bearing force.
Low temperature environment, especially in the cycle of freezing and thawing cycle, easily damaged building structure. Therefore, cold storage building material and cold storage of each part of the structure to have enough antifreeze properties.
In general, cold storage building is known for its strict insulation, sealing, sturdiness and durability to ensure the quality of buildings.
Ensure the quality of buildings.
In two, the classification of cold storage
( a ) by cold storage capacity scale
At present, cold storage capacity of division is not unified, generally divided into large, medium, small. Large cold storage refrigeration capacity is in 10000t above; medium-sized refrigerator cold storage capacity of 1000 ~ 10000t; small cold storage refrigeration capacity below 1000t.
( two) according to the cold storage design temperature
Divided into high temperature, middle temperature, low temperature and ultra low temperature four kinds big cold storage. ①general cold storage refrigeration design temperature between -2 ℃+8 ℃;②temperature cold storage refrigeration design temperature between -10 ℃-23 ℃; in low temperature, the temperature in -23℃ to -30 ℃; the ultra low speed freeze temperature -30℃ to -80℃in general.
(three ) according to the base body structure type
1 construction of cold storage
It is currently building a kind of more cold storage, can be built into the monolayer or multilayer. The building of the main general structure of reinforced concrete frame or brick structure. Construction of cold storage enclosure structure is a heavy body structure, thermal inertia is large, outdoor air temperature diurnal fluctuation and the outside surface of building envelope by solar radiation caused by diurnal temperature fluctuations, in the envelope structure of attenuation is larger, so the inside wall surface temperature fluctuation is small, the temperature is easy and stable.
2 combined plate type cold storage
The cold storage for single form, base plate for steel frame light weight prefabricated panel assembling structure, the component of the thin-wall steel production. The library board inner, outer panel are color steel plate ( substrate for galvanized steel sheet ), the library board core material for foamed rigid polyurethane or paste of polystyrene foam board. Due to the addition of the ground outside, all the components are according to the unified standards in the professional factory of prefabricated, site assembly, so fast construction progress, construction cycle is short.
3 soil cold storage
It is also called the cave of cold storage, cave for the arch structure, a single hole type, there are continuous arch form. General for masonry, and to a certain thickness of loess layer as insulating layer. Used as a low temperature cold storage of soil cave foundation, is not easy to heave gravel or rock. Because it has a suit one's measures to local conditions, obtain raw material locally, simple construction, low cost, durable advantages, in the northwest region of China gets greater progress.
4 cave storage
General construction in stone are more rigid, good integrity in rock, cave inside general lining or spray anchor hole processing, the rock cover thickness of not less than 20m.
