Solar Cold Storage The Electricity Consumption Solution

1. Introduction The solar cold storage enables effective use of solar energy for cooling of fruits /vegetables /other perishable items so as to store and preserve them for a longer duration. Today solar cold storage is treated as a most versatile product in cold chain industries. This product is changing the cold chain infrastructure landscape in most effective manner. This               product is targeted poorly electrified area or place using diesel as power sources.
2. Technology  The cold storage unit in off-grid operation, primarily runs on power generated from Solar Photovoltaic and can be switched to grid during cloudy days. During sunshine hours the electricity generated from solar photovoltaic is used to provide cooling through a vapor compression refrigeration cycle to cool a cold room and store the excess energy in Thermal Energy Storage (TES) System. In Thermal Energy Storage (TES) system the energy is stored in phase change material such as water or water salt eutectic mixture and transferred to the cold storage unit depending on the usage needs. During non-solar hours, the cooling needs of cold storage unit are met from the thermal energy storage system. Use of solar photovoltaic and thermal  energy  storage backup eliminates dependency on grid and need of diesel generator as a backup device.

3. Technical Specification                                              

           Major Components                                                        

      The system comprised mainly of the following components and equipment:

1. Cold Room,
2. Solar PV System,
3. Solar Controller,
4. Refrigeration System,
5. Thermal Energy Storage (TES) System,
6. Maintenance free Battery for meeting Auxiliary Load. Combination of all these components is unique. Any change in combination will be treated as different model of Solar Cold Storage System.

•  The PV module conforms to IEC 61730 Part-1 requirements for construction & Part-2 requirements for

testing for safety qualification.

• The PV modules qualifies relevant IEC standard.
• The PV modules used in solar power plants/ systems are warranted for their output.
• peak watt capacity, which is not less than 90% at the end of 10 years and 80% at the end of 25 years.
• All PV modules should have STC testing certificate from an NABL accredited test laboratory

1. 5. Solar Controller                                                           

                 The controller converts the DC power (DC voltage & Current) of the PV array into a controlled high or low DC voltage power, or                        converts this DC power into single-phase or three-phase alternating-current power (voltage or alternating current) suitably for driving                  the refrigeration system.

         NOTE —The Controller may also include equipment for MPPT, monitoring, metering and sine wave filters.

1. 6. Refrigeration System                                                    Refrigeration system consisting of condensing unit and evaporating unit is working on vapor compression cycle. The condensing unit generates cooling energy which can be used for charging the thermal energy storage system and to provide cooling to the cold storage depending upon the design of Solar Cold Storage system.
   7. Thermal Energy Storage (TES) System                          In Thermal Energy Storage (TES) system the energy is stored in phase change material such as water or water salt eutectic mixture and transferred to the cold storage unit depending on the usage needs. During non-solar hours, the cooling needs of cold storage unit are met through the stored cooling in the Thermal Energy Storage (TES) system.
2. 8. Electric Battery System for Auxiliary Components         The auxiliary power system consists of MPPT based inverter/ MPPT charge controller and battery. These are meant to provide electricity for auxiliary electrical loads such as fans of evaporator unit, thermal energy storage control panel, temperature controller unit, lighting, and data monitoring system.