Container houses are widely used in temporary buildings, residential buildings, and office spaces due to their modularity, mobility, and cost-effectiveness. However, their metal shells have high thermal conductivity, and without insulation, the indoor thermal environment is significantly affected by the outside temperature, leading to increased energy consumption and decreased living comfort. Therefore, the application of efficient thermal insulation materials and processes is crucial, not only improving indoor thermal comfort but also significantly reducing heating or cooling energy consumption to achieve energy-saving goals.
When choosing thermal insulation materials, container houses need to balance performance, cost, and ease of construction. Polystyrene (EPS) boards are a common choice due to their lightweight and easy-to-cut installation, but their fire resistance is generally average, requiring caution in scenarios with high fire safety requirements. Extruded polystyrene (XPS) boards improve insulation through their closed-cell structure and offer high strength and good moisture resistance, making them suitable for environments with high humidity. Polyurethane foam is favored for its extremely low thermal conductivity and integrity; on-site spraying allows for complete adhesion to the container, avoiding thermal bridging, but it is more expensive and requires strict process control. Rock wool boards, as inorganic materials, offer excellent fire resistance and sound absorption, but their weight necessitates careful consideration of structural load. In contrast, newer materials like aerogel insulation coatings utilize nanoporous structures to block heat conduction, achieving high-efficiency insulation with ultra-thin coatings. They are also easy to install and suitable for irregularly shaped structures.
The design of insulation processes must consider both material properties and the structural characteristics of the container. For internal insulation, materials such as EPS boards or rock wool boards can be directly adhered to the inner walls of the container, secured by adhesive or anchoring. External insulation must be implemented after container assembly, typically using a keel frame to support the insulation layer, covered with decorative panels to form a complete insulation system. For roofs and walls, a double-layer structure can be used, with insulation materials such as XPS boards or polyurethane foam filling the space between, further enhancing insulation. Doors and windows, being major sources of heat loss, require the use of thermally broken aluminum profiles and double-glazed windows to reduce heat conduction, and sealing strips should be added to the edges to minimize air leakage.
Sealing gaps and joints is a crucial aspect of insulation. Thermal bridges are easily formed at joints and door/window installations in container houses, leading to heat loss. Therefore, it is necessary to seal the joints of insulation materials and the junctions between the insulation layer and the container structure using expanding foam and sealing strips to ensure a seamless seal. For the external insulation system, waterproofing is also crucial to prevent rainwater penetration and maintain insulation effectiveness.
The insulation design of container houses needs to be adapted to different climates. In cold regions, the insulation layer thickness needs to be increased, and a heating system should be installed to achieve a 50°C temperature difference between indoors and outdoors. In hot regions, shading and ventilation designs need to be strengthened to reduce solar radiation heat entering the interior. For example, adding shading structures and using reflective heat-insulating coatings can effectively reduce indoor temperatures in summer.
Achieving high energy efficiency also requires consideration of construction and economic factors. EPS boards are easy to install and low in cost, making them suitable for temporary housing or dry environments; XPS boards are suitable for floor insulation; rock wool boards require mechanical fixing, resulting in higher labor costs, but offer excellent fire resistance, making them suitable for locations with high safety requirements. In extremely cold or humid regions, XPS and rock wool can be used in combination to address both moisture and fire resistance needs.
The thermal insulation of container houses requires comprehensive consideration of material selection, process design, sealing treatment, climate adaptability, and construction economics. Through scientifically sound and reasonable thermal insulation solutions, the thermal comfort of container houses can be significantly improved, energy consumption reduced, and high-efficiency energy-saving goals achieved, promoting their widespread application in the field of green building.
