This project was designed to solve Taiwan’s growing demand for larger low-temperature warehouses to provide frozen food storage and transportation.
The company, Green Value was established in 2008. With professional technology and personnel qualification, they focus on refrigeration and air-conditioning system design and planning, construction contracting, energy-saving improvement, repair and maintenance and other projects. With a team of 20 employees and advanced experience in refrigeration and air-conditioning, they have already undertaken the design and planning of many large-scale logistics centres. They have also expanded into the pharmaceutical logistic field where they focus on integrating warehousing and refrigeration system resources.
The project
The warehouse is located in Taoyuan in Taiwan and provides frozen food logistics. There are four refrigeration units, utilising heat transfer fluid as a secondary refrigerant to meet the temperature requirements of the freezer. In addition to freezer storage equipment, emergency generators and logistics facilities, the investors in this project also focused on having energy saving measures in place. In terms of power supply, a 1.8MW solar photovoltaic panel was built to provide power for the warehouse requirements
In terms of electricity consumption, the choice was made on a high-efficiency refrigeration unit and a unique heat recovery system was designed to reduce the use of electric heat.
Double success: there was reduction in electricity costs as well as reduced carbon emissions. This lead to the project obtaining the International Certification LEED** Silver Award.
The system design
The aim of the project was to achieve and maintain the freezer’s required temperature of below -18°C. This system has reserved backup units. When the main engine cannot be started, the backup unit will automatically be put into system operation within five minutes. If there is a power outage in the factory, the generator will start within three minutes; this back up system can maintain operations for up to 1 hour.
To achieve this goal, the refrigeration plant is equipped with four main machines, using R-507A as a refrigerant. Each of the J&E Hall single screw compressor has a charge of 155kg, a cooling capacity of 325kW, and dual-purpose with a redundancy system operating in parallel.
The condensation temperature is 40°C, the evaporation temperature is -40°C,and the heat transfer fluid temperature is maintained at -28°C ~ -33°C.
A new cold storage facility has implemented an advanced defrost system, designed to efficiently remove frost while enhancing overall performance and reducing electricity consumption.
This system uses Neutragel® Neo, a Heat Transfer Fluid solution from Climalife, known for its versatility in refrigeration and air-conditioning applications.
The system automatically switches between refrigeration and defrost modes.
During defrosting, 25,000 litres of Neutragel® Neo flow through the system, starting at 20°C and cooling to nearly 0°C as it passes through the evaporator.
The cooling power generated during this phase is efficiently utilised in three stages:
- Dock Buffer Area: The evaporators maintain cold room requirements with a +2° C to +7° C regime.
- Office Cooling: Neutragel® Neo continues to fan coils for air-conditioning +7°C to +12°C regime.
- Intermediate Layer Area: The fluid passes through fan coils to keep the ceiling intermediate layer cool and prevents condensation, returning to its initial temperature of 20°C.
“This innovative use of Neutragel® Neo demonstrates its adaptability and effectiveness in managing temperature across diverse applications. By integrating refrigeration and air-conditioning processes, the system improves energy efficiency and operational reliability. Neutragel® Neo is a practical solution for facilities seeking to optimize system performance and sustainable practices. We are fully satisfied with this product” – Xu Yofeng, General Manager, Green Value company.
The pressure difference adjustment system
The original design had a mechanical differential pressure gauge installed, to monitor the heat transfer fluid however the gauge would automatically shut down when the temperature was close to freezing point.
During the test run, the team had discovered that the viscosity of the heat transfer fluid increased at lower temperatures and could not meet the pressure difference of the main engine evaporator, which resulted in lower suction pressure.
Therefore, the new pressure difference adjustment system automatically controls the loading and unloading of the water pump to meet the needs of the main system.
The choice of Neutragel® Neo
The Neutragel® Neo heat transfer fluid was chosen for its viscosity and inhibitor package, that contributes to the reduction of electricity consumption. It also contains a bittering agent to prevent intoxication in case of a leak. With the support of Climalife, the pre-intervention preparation was studied carefully. The charge of the system is close 50 tonnes, and the concentration is controlled at 56% mass concentration, the freezing point is maintained above -37°C. The system is equipped with TECO (AEHFVS) water pumps models, and the host evaporator flow is 74.86m3/h.
Conclusion
This project allows the facility to make use of its space efficiently, speeding up the logistics and transportation process. At the same time, due to many energy-saving designs, users not only reduce costs, but also can also protect the environment.
Overall system information
Power consumption for cooling production / heating production / distribution network pump
- Whole system power consumption: about 700 kW
- Full load power consumption of a single host: 298 kW
- Defrost system power consumption (air blower/water pump): 10 kW
- Host ancillary equipment (cooler/cooling tower/water pump): about 150 kW
The intervention team :
Xu Yofeng/General Manager/Technician
Chen Junyuan/Associate Manager
Huang Peixian/Manager
Climalife Singapore Team