Cold Storage Room Application Case Study- Mini Rack with Invotech One Inverter compressor and one fi

01.Project Background

Following the "Dual Carbon Goals” in recent years, all trades and professions are pushing new products, new technologies, new projects to achieve energy saving and emission reduction. Improve energy utilization efficiency, reduce production costs, so as to improve the economic benefits of enterprises, improve the market competitiveness of products.

The State Administration of Market Supervision and Administration and the National Standardization Administration released GB 44015-2024 "cold storage (box) and condensing unit energy efficiency limits and energy level" on April 29, 2024, and will be officially implemented by force on February 1, 2025, which triggered the entire cold chain industry to focus on energy saving. The efficient variable speed compressor unit can significantly improve the energy efficiency index of the cold storage (box) by regulating the capacity output according to the real demanding, which has been favored by the majority of users.

Invotech, who takes "building an energy-saving and low-carbon ecological environment" as one of its missions, has developed medium and low temperature DC inverter compressors since 2019, with a displacement range of 38 ~ 72cc. In order to satisfy the requirements of customers for bigger cooling capacity, Invotech developed a control program for ONE INVERTED + ONE FIXED SPEED mini rack in 2021, which got high praise from market. 

02. Case Study

One fruit market in Ningxia, China: a batch of 500m³ cold storage is required in order to extend fruit fresh life and ensure the quality, each cold storage will have about 100 tons of fruit, room temperature required as -1 ~ 5℃, and the unit must be inverter system to reduce energy consumption, finally the customer choose Invotech INVERTER+FIXED SPEED rack unit (as Fig 1, Fig 2).

The control logic is based on the inverter speed compressor as the master, and the fixed speed compressor is as supplemented. At the high load conditions, such as when goods entering into the storage or door opening for shipping out, the fixed speed compressor will start to fast cool down to setting temperature. Then only the inverter compressor is on duty to maintain room temperature constantly by changing running speed, which can avoid compressor frequently on-off. The overall energy saving can be achieved more than 30% by using this parallel method, and the storage temperature can be maintained at a stable state of ±1℃ deviation.

Fig.1

                    

Fig.2

ONE INVERTER + ONE FIXED SPEED RACK system as fig 3:

Definition ：1.fixed speed compressor 2. inverter compressor 3. solenoid valve 4.oil filter 5.oil separator 6.condenser  7.receiver 8. solenoid valve 9.filter dryer 10.sight glass 11.EEV 12.evaporator 13.suction filter 14. suction line accumulator  15.check valve 16. Vibration absorber

03.Invotech inverter scroll compressor for Medium and low temperature application

At present, Invotech has 38 to 72 cc displacement DC inverter scroll compressor both for medium and low temperature applications. YIM series can be used at lowest evaporation temperature -30℃, while YIF can work at -40℃, the appearance and operation envelop are shown in Figure 4 and 5.

 Fig. 4

Fig. 5

04.Accessory

Besides of DC inverter compressors, Invotech can also provide the driver, main control board and electrical components (Figure 6). The main control board is compatible with DC motors and EC motors, it has two RS485 remote interfaces, it is equipped with an optional Pt100 temperature sensor for easy temperature detection such as ultra-low temperatures or cascade applications, and also a silent mode function is included.

Fig. 6

Invotech aspires to become a global first-class solution provider by providing innovative products for climate and energy industries, creating an energy-saving and eco-friendly environment. Invotech high efficiency dual compliance scroll compressor has been involved in the "China Refrigeration Society Energy Saving and ecological environment product Catalog" for many years, to provide high energy efficiency solutions to customers.