The introduction and application of foreign advanced refrigeration technology and new insulation materials have made a great breakthrough in the construction of cold storage in China. During investment and construction of cold storage, the initial investment cost and operating cost in use should be comprehensively considered according to different regions and conditions, and a relatively economical and reasonable cold storage should be constructed.
At present, the construction methods of cold storage buildings mainly include three forms: one is the civil cold storage built with block and reinforced concrete structure plus thermal insulation; the second is the light steel structure plus the prefabricated cold storage type; the third is the civil construction and steel-concrete structure plus the prefabricated cold storage type .
The selection of specific types can be determined mainly according to factors such as different regions, geographical environments, investment costs, and operating costs.
Civil structure: there are technical improvements
The civil cold storage is divided into single-layer and multi-layer. The single-layer cold storage adopts the beam-slab structure, and the multi-layer cold storage adopts the beam-free floor structure. The walls, columns, floors and other main bodies of the cold storage are made of blocks and reinforced concrete structures. The inner side of the cold storage wall is pasted with a thermal insulation layer. Both sides of the thermal insulation layer need to be moisture-proof and vapor barrier layers, and the inner side should be a civil protection layer. The insulation material of cold storage is developed from rice husk, cork, polystyrene to polyurethane spray. Moisture-proof and vapor-barrier materials have eliminated the practice of petroleum asphalt linoleum, and replaced the method of on-site paving with polyurethane waterproof coating and polyethylene film. The envelope structure of the civil cold storage is a heavy structure, and the thermal inertia is large. The temperature fluctuation caused by the outside air temperature and solar radiation is small, and the storage temperature is relatively stable.
The advantages of civil cold storage are energy saving, sturdiness, high load-bearing, good fire resistance and durability; the disadvantages are that the construction period is long, the self-weight is heavy, the geological conditions are high, and there are many columns in the cold storage, which affect the stacking of goods and reduce the effective use of the cold storage. volume.
Among the existing cold storages in my country, multi-storey civil cold storages built in the early 1970s and 1980s account for the majority. Taking Shanghai as an example, if calculated by capacity, civil cold storage accounts for 82.41% of the city's cold storage capacity. %; If the statistics are based on the number of seats, the civil construction should account for 86.13% of the total number of seats.
The advancement of cold storage construction technology has also given civil cold storage more competitive advantages. Ma Shuang, an engineer from Dalian Bingshan, told reporters: "There are three types of multi-storey cold storages in civil construction. One is the beamless floor structure, which has a market but is not mainstream, and is mainly based on the local wholesale market. Span, and mechanized operation; the third is the secret beam structure, which can realize large-span operation and stable bottom. Bingshan highly recommends users to use this type.”
Steel frame structure + thermal insulation board: a lot of promotion
The development of light steel structure and the needs of modern logistics have promoted the rapid development of large-column network and large-span steel structure prefabricated cold storage. my country has carried out large-scale promotion of steel frame structure cold storage since 2000.
The steel frame structure cold storage adopts light steel structure types such as steel columns and steel beams, and the heat preservation adopts prefabricated storage panels on-site splicing. There are two structural forms between the light steel structure and the thermal insulation board: one is the outer structure and the other is the inner structure. The light steel load-bearing structure is on the outside of the insulation board, which is called the outer structure, and vice versa, the inner structure, and the outer structure uses less steel than the inner structure.
The steel frame structure cold storage is beautiful, the size and height can be adjusted, the construction period is short, the storage is regular, and automatic processing can be realized. The inferior steel structure cold storage is often exposed to wind and rain, and the personnel management is not in place, problems such as corrosion and peeling will occur for a long time, especially in coastal cities, typhoons and seawater can exacerbate corrosion. Coupled with outdoor sunlight, it has an impact on the temperature in the cold storage, frequent startup, energy consumption, and parts consumption. At the same time, pay attention to the problem of water leakage at the joints.
In recent years, the steel market has been sluggish, and the investment in cold storage with steel frame structure is less than that in civil construction. Coupled with the gathering of various advantages, it has ushered in a period of high development recognition.
Civil construction + steel construction combination: getting better and better
With the advancement of science and technology and the development of the refrigeration industry, new cold storage construction methods have attracted much attention. For example, the combination of civil construction and steel construction replaces the construction mode and operation mode of the original cold storage building with a new architectural concept of standardization, modularization, and factoryization. The use of this combined cold storage is getting wider and wider, and the building scale is also getting bigger and bigger.
The two-party combined cold storage has many advantages. For example, aesthetics: There are dozens of optional colors for the sandwich panel and outer protective structure, which can meet the needs of any style of building and achieve satisfactory results. Thermal insulation: The use of polyurethane or polystyrene sandwich panels has low thermal conductivity, high strength and good thermal insulation effect. Strong plasticity: The specifications of the sandwich panels for all construction combined cold storages conform to the building modulus, and the cold storages can be separated and arranged at will according to customer requirements. It has the advantages of short construction period, quick installation, food hygiene requirements in the warehouse, durable building structure, excellent material quality, and accurate temperature control.