Construction Costs, Refrigeration, and Equipment Comparison Guide

8-1. Comparison of Construction Costs by Temperature Zone (Normal, Refrigerated, Frozen)

Summary of Construction Costs (Architecture + Equipment) Comparison by Temperature Zone

*This is a relative ratio and rough estimate based on the construction unit price per tsubo of a normal temperature (dry) warehouse being "1.0 (baseline)".

Temperature Zone	Specification Overview	Relative Construction Cost Ratio	Main Cost Increase Factors
Normal Temp (Dry)	Standard structure (No A/C to general A/C)	1.0 (Baseline)	Basic structure only
Refrigerated (+5°C)	Chilled zone (Insulation panels + Refrigeration equipment)	1.2 to 1.4 times	・Installation of urethane insulation panels (walls/ceiling) ・Refrigeration units for chilled use, anti-condensation doors
Mild Frozen (-5°C)	High-function chilled to ice temperature zone	1.35 to 1.55 times	・Increased thickness of insulation materials (around 100mm) ・Reinforced condensation/frost prevention measures for dock shelters and antechambers
Frozen (-25°C)	Class F frozen warehouse (Deep freeze)	1.6 to 2.0 times or more	・Extra-thick insulation panels (150-200mm) ・Underfloor frost heave prevention heaters/pits ・Double frost-proof shutters, large refrigerating machines

Specific Factors for Equipment Specifications and Cost Increases in Each Temperature Zone

1. Normal Temperature (Dry Warehouse)

• Equipment Features: General high-load bearing floors, dust-proof painting, standard lighting and ventilation equipment.
• Cost Factors: Basic structural costs of the building itself (steel frame, outer walls, roof) only.

2. Refrigerated (+5°C)

• Equipment Features: Storage zone for dairy products, meat/fresh fish, and perishable foods.
• Cost Increase Points:
  • Insulation Method: Seamless installation of urethane insulation panels about 75mm to 100mm thick on the inside of the warehouse (inner BOX structure).
  • Openings: Installation of dock seals and dock shelters at berth sections to prevent outside air intrusion and condensation.

3. Mild Frozen (-5°C)

• Equipment Features: An intermediate zone between chilled and frozen to prevent thawing (ice temperature, mild freezing storage for meat and fish).
• Cost Increase Points:
  • Condensation/Frost Prevention Measures: Because the difference between the indoor and outdoor temperatures is larger than in the +5°C zone, double antechambers and dock seals with anti-frost heaters are mandatory.
  • Cooling Capacity: Along with the increased horsepower of compressors, costs arise for expanding the capacity of high-voltage power receiving equipment (cubicles).

4. Frozen (-25°C)

• Equipment Features: Long-term storage zone (Class F) for frozen foods, ice cream, processed marine products, etc.
• Cost Increase Points (Biggest Factors):
  • Underfloor Frost Heave Prevention (Heaters/Ventilation Pipes) Work: To prevent "frost heave," where cold air in the warehouse travels through the floor slab and freezes the ground, causing it to heave and destroy the building, special civil engineering and foundation work is required to construct electric heaters, ventilation pipes, and a double slab structure under the floor (this alone incurs enormous costs).
  • Extra-Thick Insulation Materials: High-density insulation panels with a thickness of 150mm to 200mm or more are used.
  • Frost-Proof Shutters / Antechamber Systems: The antechamber itself is made into a dehumidified and frost-proof space (around -5°C to 0°C), and special doors containing heating wire elements are placed to prevent the doors from freezing shut due to condensation or icing.

Perspective on Running Costs (Maintenance Costs)

Not only initial construction costs, but also electricity bills and maintenance costs surge in proportion to the temperature zone.

• Electricity Bills: The electricity bill for a -25°C frozen warehouse reaches 3 to 5 times or more that of a normal temperature warehouse.
• Decarbonization / Freon Regulation Compliance: Since the 2020s, based on the Act on Rational Use and Proper Management of Fluorocarbons, it has become mainstream to adopt "natural refrigerants (CO₂ refrigerants and ammonia refrigerants)" with low environmental impact. It is important to note that the initial equipment cost is 20% to 30% more expensive than conventional Freon-based refrigerating machines.