Pomegranate Fresh-keeping Storage and Transit Cold Storage Construction Project

Project Name: Professional Subcontracting for the Constant Temperature Warehouse of the Shiliu Integrated Cold Chain Wholesale Market in Yicheng District.

Completion time: September 2024, Zaozhuang City, Shandong Province, China.

Construction specifications: The warehouse spans 1,500 square meters with 6-meter ceiling clearance and a storage capacity of 9,000 cubic meters.

Cold storage temperature: 4℃～5℃.

Cold storage types: pomegranate storage and transit cold storage.

The construction period is 30 days, and the debugging and cooling period is 5 days.

Completion date: July 2024.

Refrigeration compressor system: The system employs four box-type air-cooled integrated units, with refrigeration compressors being Lefukang piston compressors.

The evaporator in the tank is a suspended air cooler.

Design service life: 20 years.

The professional subcontracting project for the temperature-controlled warehouse of the Shiliu Comprehensive Cold Chain Wholesale Market in Yicheng District leverages the region's core advantages in the pomegranate industry. This key infrastructure initiative focuses on critical post-harvest storage, transit, and preservation needs. As the largest dedicated cold storage facility supporting Shandong Province's pomegranate trading market, the project fills the gap in large-scale specialized cold chain warehousing within the region. It injects strong momentum into the high-quality development of the local pomegranate industry, facilitating its scaling, standardization, and industrial upgrading.

Pomegranate storage technology

Pre-cooling: 4~5°C, 0.5 m/s, RH 85%~90%,3~5 days until the core reaches 4~5°C

Refrigeration: 4℃±0.5℃, RH 90%~95%, regular air exchange in standard storage, controlled atmosphere with O₂ 3%~5%/CO₂ 5%~8%

After storage, pre-cool for 3-5 days under conditions of 4-5°C, 0.5 m/s wind speed, and 85%-90% relative humidity (RH), until the core temperature reaches 4-5°C. Upon completion of pre-cooling, secure the bag opening (no full sealing required for micro-perforated bags).

During the pre-cooling period, avoid excessive stacking to ensure unobstructed air ducts; store and stack materials by origin/variety.

1. Temperature and humidity control: Maintain constant temperature at 4°C ±0.5°C; relative humidity (RH) at 90%~95% (excessively low causes dehydration and shrinkage, excessively high leads to mold growth); avoid temperature fluctuations in the storage room exceeding ±1°C/day.

2. Gas environment (optional controlled atmosphere): Standard refrigeration: Enhance ventilation and air exchange, with air replacement every 3–5 days; Controlled atmosphere recommendation: O₂ 3%–5%, CO₂ 5%–8%, which can significantly extend the shelf life.

3. Stacking and Inspection: Stacking density 100~150 kg/m³; box spacing 2~3 cm, stack spacing 10~15 cm, with sufficient clearance from the warehouse roof/side walls/air ducts; weekly random sampling and timely removal of diseased or rotten fruits; thorough ventilation once monthly.

4. Ethylene control: Ethylene absorber is placed per cubic meter to inhibit browning and aging.

The professional subcontracting project for the temperature-controlled warehouse of the Shiliu Comprehensive Cold Chain Wholesale Market in Yicheng District leverages the region's core advantages in the pomegranate industry. This key infrastructure initiative focuses on critical post-harvest storage, transit, and preservation needs. As the largest dedicated cold storage facility supporting Shandong Province's pomegranate trading market, the project fills the gap in large-scale specialized cold chain warehousing within the region. It injects strong momentum into the high-quality development of the local pomegranate industry, facilitating its scaling, standardization, and industrial upgrading.

In construction techniques and material selection, this project adheres to high standards and strict requirements to ensure the preservation performance and service life of the temperature-controlled storage facility. The storage structure is constructed with polyurethane foam composite panels, with a minimum thickness of 100mm. Both sides are equipped with spray-coated steel plates that combine flame retardancy and environmental friendliness, free from chlorofluorocarbon compounds, meeting food hygiene standards. These panels effectively block external temperature transfer, creating a stable environment for pomegranate storage. The thermal insulation system focuses on optimizing panel joint sealing, controlling joint gaps within 1.5mm, and applying non-toxic sealant evenly at joints to eliminate cold bridge effects. Specialized sealing and insulation treatments are also applied to critical areas such as floors and pipeline openings to ensure uniform temperature distribution. The refrigeration system employs high-efficiency energy-saving equipment with a bypass air supply and return design, preventing direct cold air exposure to pomegranate surfaces to avoid skin dehydration, wrinkling, and color dulling. The system precisely maintains indoor temperatures between 0-5°C, with pre-cooling zones controlled at 8-10°C. A high-humidity regulation system dynamically adjusts humidity levels based on pomegranate loading capacity, maximizing freshness retention and commercial value.

During the construction process, we strictly adhered to the project bidding requirements and industry standards by forming a professional construction team, equipping with complete construction equipment and safety protection facilities, and implementing comprehensive quality control and safety management measures. Prior to construction, we completed preparatory work including site surveys and material inspection upon arrival. All materials entered the site were accompanied by certificates of conformity and technical supervision bureau test reports, ensuring compliance with project requirements. During construction, we implemented zoned operations and layered control, with particular emphasis on critical phases such as storage chamber sealing, refrigeration pipeline welding, and electrical debugging. Nitrogen gas shielded welding was employed for pipeline connections, and vibration damping treatment was applied during refrigeration unit installation. Temperature control probes were installed at representative locations within the storage chamber, avoiding direct cold air exposure to ensure construction quality met standards. Additionally, we rigorously enforced safety regulations by setting up construction barriers and warning signs, requiring all personnel to wear full protective equipment, eliminating potential hazards, and ensuring the project was completed on schedule, with quality and safety guaranteed.

As the core supporting facility of Shandong Province's largest pomegranate trading market, this project will become the region's leading specialized storage and transfer cold storage with comprehensive facilities and advanced technology upon completion. It will effectively resolve post-harvest storage challenges for pomegranates in Yicheng District and surrounding areas, significantly reducing post-harvest loss rates. Through professional temperature-controlled preservation and transfer services, the facility will extend pomegranate freshness, enable off-peak sales, and help growers and distributors mitigate market price volatility risks while enhancing product value. By addressing key bottlenecks in storage, transfer, and distribution, the project will promote standardized and scaled pomegranate trading, attract more upstream and downstream enterprises, and strengthen the pomegranate industry supply chain system.