Thermal Insulation of Housing Containers
For thermal insulation of housing containers, it is essential to focus on materials, structure, craftsmanship, and performance parameters. Detailed analysis can be conducted from the following aspects:
Material selection is the foundation of thermal insulation. Wall materials directly affect heat conduction efficiency. For example, the Apple Cabin adopts a composite sandwich panel structure, filled with a high-density polyurethane insulation layer in the middle, and combined with hollow tempered glass to effectively block heat transfer. Red Maple Modular Buildings use polyurethane sandwich panels or rock wool as insulation layers, achieving thermal performance that meets or exceeds traditional brick-and-mortar building standards. The Baotou Camp Container House employs a thermal-break lining structure, filling the space between the steel frame and interior wall panels with rigid polyurethane foam and adding rubber insulation pads, reducing heat exchange efficiency by approximately 40%. The lower the thermal conductivity of the material, the stronger its insulation performance. For instance, the thermal conductivity of polyurethane is typically ≤0.024W/(m·K), and that of rock wool is ≤0.040W/(m·K), both significantly lower than that of ordinary steel.
Structural design needs to address the cold and hot bridge effect. Metal container walls are prone to forming cold and hot bridges, leading to rapid heat loss. Improvement solutions include adopting a double-wall structure, with an outer layer of anti-corrosion color-coated steel plate reflecting sunlight, a middle layer of polyurethane foam blocking heat conduction, and an inner layer of fire-resistant gypsum board for humidity control. Alternatively, through adaptive container combination design, such as stacking two containers to form an air insulation layer in between, actual measurements show that the cabin warms up 22 minutes slower than the outdoors in summer, and the indoor temperature only drops by 1.3℃ after being closed for 8 hours in winter. Additionally, the fit between doors, windows, and frames, as well as corner sealing, should be optimized to avoid cold bridges caused by gaps.
Craftsmanship details determine overall performance. Jointing craftsmanship affects the continuity of insulation. For example, in temporary construction scenarios in Shijiazhuang, the gap between panel joints is required to be ≤1mm, and cold bridges are eliminated through sealant or welding processes. Qingdao Jiecheng Hongye Refrigerated Containers adopt a full-process technical inspection mechanism to ensure the uniformity of the insulation layer thickness and reduce equipment failure risks. Sealing performance is also crucial, with a waterproof rating of IP66 or above required to withstand severe weather conditions such as heavy rain and snow.
Performance parameters need to comply with industry standards. The national 'Technical Standard for Steel Structure Integrated Houses' requires the heat transfer coefficient of residential container walls to be ≤0.45W/(㎡·K). The Apple Cabin reduces its comprehensive heat transfer coefficient to a K-value of ≤0.28W/㎡·K through a multi-layer insulation system, meeting ultra-low energy consumption building standards. When purchasing, attention should also be paid to the thickness of the insulation layer (usually ≥50mm), power supply compatibility (such as 380-volt three-phase power support), and after-sales service terms, with lifetime service reducing long-term maintenance costs.
