FIELD OF INVENTION

The present invention generally relates to cold storage system, particularly to solar powered cold storage system. More particularly, the present invention relates to cost effective and eco-friendly solar operated stand-alone system which is portable. Advantageously, the present invention relates to an energy efficient system.

BACKGROUND ART

In general, cold storage is a form of refrigerated storage to maintain the desired room environment required to preserve a range of products that includes fresh fruits and vegetables, industrial raw materials, meat, fish, poultry and dairy products, pharmaceutical products etc. Most of the cold storage systems are equipped with integrated refrigeration equipments and electronic system designed for better storage condition control and energy savings. US20150276277 relates to cold storage unit apparatuses designed for high energy efficiency which may include a refrigeration system; a box enclosing an interior space, the box formed by a plurality of insulated sides; an entry into the interior space including a plurality of openable barriers facilitating preventing entry of heat or moisture into the interior space; and a power system connected to the refrigeration system, the power system facilitating independent operation of the refrigeration system when not connected to a power grid, and further facilitating a net energy use of zero from a power grid when connected to a power grid. W02014070755 discloses a solar powered thermally conditioned space, which, in an embodiment, may be used to provide a cold storage arrangement for preservation of perishable commodities over an extended time period. CN101441014 relates to a solar energy photovoltaic energy storage refrigerator system comprising a solar energy photovoltaic energy electricity generation system and a refrigerating circulation system of a refrigerator. However, domestic refrigerators are made in a small range of sizes. Adjustable shelves and trays are the major limitations of the house hold refrigerators. Further, the prior art disclosed the use of special silicone gel based storage system for energy storing and recovery process. The basis of the refrigeration system selection is based on the amount of heat to be extracted from a closed surface and to bring it the required storage condition. Hence, the load shall vary depending on the products being stored in the refrigerated chamber. Accordingly, said multi throttled energy storage device kept to absorb the energy is also the load to be taken into consideration of the system selection and it will be exponentially raise the requirement of refrigeration as well as electrical load of the system.

CN202885391 relates to a solar energy refrigerated cabinet which is powered completely by solar energy, simple in structure, high in usage of cabinet space, capable of moving bodily, low in noise of a unit, dual-purpose at high temperature and low temperature, safe and reliable in running, energy-saving and environment-friendly. However, the arrangement of equipments is such that batteries and inverters mounted horizontally above the storage will affect the performance of the cold storage and also the cost for the cold store infrastructure stability will be more. Further, the batteries and inverter mounted on the top will have very less space for the servicing and trouble shooting.

3204/DEL/2014 discloses a system comprising a solar power system for providing solar power; an AC grid supply for providing AC power; a battery inverter system for the backup power supply; and a battery management system to optimize the use of the battery. The system employs enhanced utilization of said multiple power sources to provide electricity to a refrigerator, wherein the refrigerator is adapted to operate from either of said multiple power sources as per the availability of power sources. However, said system is used mostly for house hold food storage and it is stationary.

CN2446465 discloses an electric refrigerator using solar batteries as power supply. The utility model comprises an ordinary electric refrigerator, a converter which is arranged on the rear part of the ordinary electric refrigerator, solar batteries and a light collecting plate thereof. When the utility model is used, power generated by the solar batteries is delivered to the converter of the ordinary electric refrigerator by an output end, and the converter converts direct current into alternating current and input the alternating current into the power end of the electric refrigerator to make the electric refrigerator work normally. CN108195112 discloses a portable photovoltaic refrigerator and belongs to the technical of solar energy. CN108088138 discloses a mobile solar energy refrigerator for traveling outdoors. The mobile solar energy refrigerator comprises a refrigerator box body, reset handles, and rollers; the refrigerator box body is divided into an upper cover part provided with a solar panel; the interior of the box body is provided with a refrigeration system and a refrigeration cavity; a power box is also arranged inside the box body, and the power box includes an inverter controller assembly and an accumulator assembly; and a display interface is connected outside the power box, and the solar panel is connected with an inverter controller in the power box.

CN104158280 discloses a photovoltaic refrigerator which is powered by solar energy and commercial power jointly and has a variable frequency starting function.

WO20 16201396 discloses a solar powered portable refrigeration unit that has an insulated bay for storing perishable goods. An electrical controller controls solar cells, batteries and a petroleum powered generator for providing energy to the refrigeration unit where an inverter is used converting DC voltage from the battery to an AC voltage.

CN202333859 relates to a solar energy refrigerator battery accumulator, which comprises a box body, a storage battery, a solar charging controller, an electrometer, power switches, mobile phone charging interfaces and a power output interface. The conventional cold storage systems are usually fixed, not modular and very large in size. They are usually powered by conventional power sources like diesel or from national grid. As the cost of diesel is variable, the operational expenses are very high. Further, the life span of conventional cold storage system is less. Also, the capacity addition is complex in conventional systems.

Accordingly, there exists a need for a cost effective and eco-friendly portable solar powered cold storage system which overcomes the drawbacks of conventional systems.

OBJECTS OF INVENTION

One or more problems of the prior art may be overcome by various embodiments of the present invention.

Accordingly it is the primary object of the present invention to provide solar powered cold storage system

Another object of the present invention is to provide a portable solar powered cold storage system.

It is another object of the present invention to provide cost effective and eco-friendly solar operated cold storage system. It is another object of the present invention to provide an energy efficient cold storage system, wherein said system decides the necessity of the cooling requirement and uses the energy efficiently.

It is another object of the present invention, wherein the system is capable of working for approximately 2 to 3 days during non solar hours.

It is another object of the present invention to provide a stand-alone system that acts us energy management system integrated in a container and making it portable. SUMMARY OF INVENTION

Thus according to the basic aspect of the present invention there is provided a portable solar powered cold storage system comprising: solar power source; string junction box; charge regulator; solar off-grid inverter; battery unit; cooling unit; and evaporator unit, wherein output from the solar power source is fed into the string junction box, output from the string junction box is then fed to the charge regulator, wherein DC output from the charge regulator is distributed to the solar off-grid inverter which feeds AC output into control unit junction box, wherein output from the control unit junction box is then fed to the cooling unit, and evaporator unit as per the user’s requirements, and wherein a part of DC output from the charge regulator is fed to the battery unit which stores the electrical energy produced by the solar power source and supplies the stored energy to run connected DC loads through DC junction box during non solar hours.

It is another aspect of the present invention, wherein the charge regulator limits the rate at which electric current is added to or drawn from the battery unit.

It is another aspect of the present invention, wherein the charge regulator tracks the maximum power point of a photovoltaic (PV) array to deliver the maximum available current for charging the battery unit.

It is another aspect of the present invention, wherein the portable solar powered cold storage system further comprising of variable frequency drive (VFD) for utilization of energy and optimal sizing of solar system. It is another aspect of the present invention, wherein the portable solar powered cold storage system works for 2-3 days during non solar hours. It is another aspect of the present invention, wherein the system is configured to decide the necessity of the cooling requirement and uses the energy efficiently.

BRIEF DESCRIPTION OF DRAWINGS Figure 1: illustrates block diagram of the solar powered cold storage system according to the present invention.

Figure 2: illustrates the solar powered cold storage system according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

The present invention as herein described relates to portable solar powered cold storage system. It is a stand-alone system that acts us energy management system integrated in a container and making it movable or portable. Referring to Figure 1, the cold storage system comprises of solar power source [1]; string junction box [2]; charge regulator [3]; solar off-grid inverter [4]; battery unit [5]; cooling unit [6]; and evaporator unit [7]. The solar power source [1] consists of multi crystalline solar photovoltaic (PV) cells connected in series or parallel combination which produces electrical power when exposed to sunlight. The output from the solar power source [1] is fed into the string junction box [2], said string junction box allows one or more photovoltaic strings to be connected in parallel, deriving one common array output for the multiple array inputs. The output from the string junction box [2] is fed to the charge regulator [3] which is used as PV converter along with a hybrid inverter, said charge regulator [3] limits the rate at which electric current is added to or drawn from electric batteries. It tracks the maximum power point of a PV array to deliver the maximum available current for charging batteries. The output from the charge regulator [3] is direct current (DC) output which is then distributed to the solar off-grid inverter [4]. It includes photovoltaic string protection, overvoltage protection and a DC output switch dis-connector. The off-grid inverter [4] converts the DC output into alternating current (AC) and fed into control unit junction box [4b] through AC junction box [4a]. The output is then fed to AC loads such as the cooling unit [6]; and evaporator unit [7] as per the user’s requirements.

The cooling unit [6] can be used for one or more applications such as vegetable and other commodities storage, milk chillers and medicine storage chillers. The chiller and collection units are containerized (portable) with facility to mount on truck and plug in with the ground mounted solar system.

A part of DC output from the charge regulator [3] is fed to the battery unit [5], said battery unit which consists of one or more lead-acid batteries stores the electrical energy produced by the solar PV modules during the day time and supplies the stored energy to run connected DC loads [9] through DC junction box [8] during night or next day if sunlight is not available. The maximum electrical energy which can be stored in the battery is specified by the ampere hour (Ah) capacity of the battery. The system is further provided with Variable Frequency Drive (VFD) [10] or DC motors for better utilization of energy and monitoring unit to monitor power and temperature.

The cold storage system of the present invention is walk in storage compartment and has the capacity to store much more than a house hold refrigerator can store. Advantageously, the extra energy is not required for the storage purpose and hence the additional refrigeration capacity as well as the electrical power could be avoided. The surplus energy from the sunlight shall be stored in the batteries externally and shall be utilized whenever it is required.

Further, the batteries and inverter are mounted on an independent battery compartment [5 a] thereby providing ease for installation and servicing of the same. The compartment of said system is provided with ventilation to avoid such heat transfer to the refrigerated space. The system is provided larger insulation thickness to avoid all sort of heat ingress to the refrigerated storage. Also, PUF insulation panels are replaceable based on the need and requirements. The system integrates the cold store [11] in the container and making it movable from one location to another as shown in Figure 2. Said incorporation of movable / transportable cold store with solar panels shall be efficiently utilized for the perishable goods storage throughout the cold chain. Also, the system is capable of working for 2-3 days efficiently during non solar hours after completely charged and the system decides the necessity of the cooling requirement. The following are the advantages of the present invention:

User-friendly and flexible system. • Integrating the cold store in the container and making it movable from one location to another.

• Unitized hence can be expanded to any level.

• Eliminates the need for extra energy for storage purpose.

• Can be installed in any terrain.

• Larger in size.

• Cost-effective.

• Provides ease in maintenance.

• Efficient energy management.

• Self- sustainability.