DESC:FIELD OF THE INVENTION
[001] The present invention relates to a vapor compression based refrigeration system utilizing fan based cooling for storing food products. Particularly, the present invention relates to a low-cost vapor compression refrigeration system that utilizes fan based cooling to store and preserve the food product for a longer time.
BACKGROUND OF THE INVENTION
[002] Agriculture is a central part of India’s economy and currently it is among the highest farm producers in the world. Agricultural development is critically significant to enhancing nutrition and food security. Vegetable, fruits, oil, proteins are some of the important agriculture commodities in India.
[003] Once harvested, suitable storage of fruits and vegetables is important under apposite conditions in order to maintain their integrity and prevention of infection and spoilage. Proper storage and supervision ensures fresh fruits and vegetables sustain their freshness and flavor longer and are also healthy for consumption.
[004] Refrigeration of fruits and vegetables is crucial as cold temperatures hinder the growth of microorganisms that damage food such as mold, yeast and bacteria. It further helps slow the deterioration of foods and reduces the food’s own natural development that leads to decay and ripening.
[005] Conventionally, efforts have been made to retain the freshness of fruits and vegetables by using a freezer or refrigerate the food product. The major disadvantage of conventional freezers or refrigerator systems is the cost to run it. Further, they require high maintenance due to the general snags the appliance can have over its lifetime. The conventional refrigeration systems adversely affects the environmental conditions leading to acceleration of climate change.
[006] Further, patent application number 202014021995 discloses a refrigeration apparatus comprising a main refrigerant circuit including a positive displacement compressor, a condenser, an expansion valve, an evaporator, through which a refrigerant circulates successively in a closed loop circulation, and a lubrication refrigerant line in fluid connection with the main refrigerant circuit and connected to the compressor for lubrication of said compressor with the refrigerant. The apparatus also comprises a refrigerant container connected between the condenser and the expansion valve, said refrigerant container being configured to retain a quantity of refrigerant, the lubrication refrigerant line being connected to said refrigerant container. The refrigeration apparatus further comprises heating means for heating the refrigerant contained in the refrigerant container.
[007] Further, Chinese patent application number CN104920588A discloses a vegetable storing method. The technical scheme is characterized in that the vegetable storing method comprises the following steps: selecting seasonal vegetables which are not produced in greenhouses and of which the soluble solid content is lower than 6%, precooling the selected vegetables, wherein a selection standard comprises that the maturity of the vegetables is seventy percent to ninety percent, the vegetables are free from influence of injuries, diseases and insects, and the vegetables need to be precooled within one day from being picked from a planting site; packaging the precooled vegetables in a fresh keeping bag, wherein the thickness of the fresh keeping bag is 0.02-0.05mm, and forming 1-5 holes in each of two opposite lateral surfaces of the fresh keeping bag; placing the fresh keeping bag and the vegetables in the fresh keeping bag in a refrigerating room so as to refrigerate the vegetables in the fresh keeping bag, wherein the refrigerating temperature is within the range of 0.4-0.6 DEG C higher than freezing points of the vegetables in the fresh keeping bag, a certain fluctuation error of the refrigerating temperature is permissible, and a lower limiting value of the fluctuation is higher than the temperature that ice nucleuses are formed.
[008] The cited patent applications relates to pump based vegetable storage method methods that are challenging to install, requires a lot of major work further necessitating high maintenance cost determinable to its moving parts and leading to questionable sustainability. Also, the shelf-life of produce after refrigeration can be subjective to the greenhouse production method accrediting to its lower than 6% soluble solid content.
[009] The present state of art including the ones mentioned above does not relates to a low- cost and low-maintenance eco-friendly refrigeration systems. Therefore, there is need to provide a low-cost cold storage refrigeration system for storage of food products without requiring high preservation of the appliance.
[0010] To this end, the present invention concerns a Vapor Compression Refrigeration System for farmers for storage of wide variety of food products with efficient, ecological and enhanced cooling control of the product.
OBJECTIVES OF THE INVENTION
[0011] The primary objective of the present invention is to provide a low-cost Refrigeration system for storing fruits and vegetables.
[0012] Yet another object of the present invention is to provide a Vapor Compression Refrigeration system for farmers for storing fruits and vegetables.
[0013] Another object of the present invention is to provide a Refrigeration system with enhanced cooling control on the produce.
[0014] Another object of the present invention is to provide a Refrigeration system requiring low-maintenance for its functioning over its lifetime.
[0015] Yet another objective of the present invention is to reduce high power consumption and cost associated therewith by employing thermal insulation layers within the refrigeration system.
[0016] Other objects and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, wherein, by way of illustration and example, the aspects of the present invention are disclosed.
SUMMARY OF THE INVENTION
[0017] The present invention relates to a vapor compression based refrigeration system comprising a cold storage chamber, a stacking system, a compressor, a condenser, an evaporator, a plurality of fans, an external power source, a motor, a liquid sub-cooler, an expansion valve, a flash chamber, an insulation wall, a regenerative heat exchanger and a leak proof pipes, and a thermostat. The system offers green refrigerant with high thermal conductivity such as, but not limited to, R134a refrigerant into the compressor of the system. A plurality of fans are configured into the refrigeration system. The low power consumption fans are configured to manage the air circulation and manage the temperature of the refrigerant to maintain the uniformity of the air. The fan is positioned opposite to a door of the storage chamber to assimilate regenerative heat exchanges. Further, industrial fans are incorporated instead of high power air conditioning thus, requiring low power consumption and further relating to an enhanced cooling control on the product. Further, a flash chamber is used to separate refrigerant liquid and vapor at an intermediate pressure and remove entrapped gases present in the refrigerant.
[0018] The system is simply an energy-efficient refrigeration system with optimized specific energy consumption (kW/TR) comprised of a plurality of component and green refrigerants for achieving economical, ecological and cleaner cooling impact on the food product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when taken in conjunction with the detailed description thereof and in which:
[0020] Figure 1 illustrates the various components of the vapor compression refrigeration system;
[0021] Figure 2 illustrates the compressor provided in the present invention;
[0022] Figure 3 illustrates the condenser provided in the present invention;
[0023] Figure 4 illustrates the air fan provided in the present invention;
[0024] Figure 5 illustrates the expansion valve provided in the present invention;
[0025] Figure 6 illustrates the flash chamber provided in the present invention;
[0026] Figure 7 illustrates a flow diagram of the method of present invention.
[0027] Figure 8a illustrates graphical representation of the cooling capacity in a condensing unit;
[0028] Figure 8b illustrates graphical representation of the power consumption in a condensing unit;
[0029] Figure 8c illustrates graphical representation of the heating capacity in a condensing unit;
[0030] Figure 8d illustrates graphical representation of the current (in amperes) in a condensing unit;
[0031] Figure 8e illustrates graphical representation of coefficient of performance in a condensing unit;
[0032] Figure 8f illustrates graphical representation of mass flow in a condensing unit.
[0033] Figure 9 illustrates performance curve of the liquid line.
[0034] Figure 10 illustrates performance curve of the suction line.
DETAILED DESCRIPTION OF THE INVENTION
[0035] The following description describes various features and functions of the disclosed system and method with reference to the accompanying figure. In the figure, similar symbols identify similar components, unless context dictates otherwise. The illustrative aspects described herein are not meant to be limiting. It may be readily understood that certain aspects of the disclosed system and method can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein.
[0036] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[0037] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.
[0038] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention.
[0039] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise
[0040] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. The equations used in the specification are only for computation purpose.
[0041] The present invention generally relates to a vapor compression refrigeration system (VCRS) to store and preserve wide range of perishable products, such as but not limited to fruits and vegetables, in a fresh state. The present invention utilizes a plurality of components and green refrigerant in a low-cost cold storage refrigeration system. The refrigerants and the components utilized in the present invention exhibits economical, ecological and cleaner cooling impact that optimizes energy consumption (kW/ TR) of the system.
[0042] The main embodiment of the present invention is vapor compression refrigeration system (100) which comprises a cold storage chamber (102), a stacking system (104), a compressor (106), a condenser (108), an evaporator (110), a plurality of fans (112), an external power source (114), a motor (116), a liquid sub-cooler (118), an expansion valve (120), a flash chamber (122), an insulation wall (124), a regenerative heat exchanger (126) and a leak proof pipes(128), and a thermostat (130).
[0043] Figure 1 illustrates various components of the present invention, which are discussed here in detail:
[0044] (a) Cold Storage Chamber (102): A cold storage chamber (102) is configured with a direct evaporative cooling system to enhance cooling capacity along with a supplemental refrigeration that accommodates a latent heat in the cold storage chamber. In a preferred embodiment, the cold storage chamber (102) comprises of a four-level stacking system (104) with a minimum height difference of 3 meter on each wall, which enables easy installation and utilization of the chamber within a limited spaced area.
[0045] (b) Compressor (106): Figure 2 of the present invention illustrates a compressor (106) that is configured to receive a green refrigerant with higher thermal conductivity. The green refrigerant entered into the compressor enhances the efficiency of the refrigeration system. In a preferred embodiment, a reciprocating compressor is driven by a motor to compress a R134a refrigerant to raise the temperature and vapor pressure of the refrigerant.
[0046] (c) Condenser (108): Figure 3 of the present invention illustrates a condenser (108). The condenser (108) is connected with the compressor (106) to receive the hot and pressurized vapor refrigerant gas. The condenser (108) cools the received refrigerant by converting it into a liquid state. In a preferred embodiment, the condenser (108) is equipped with a plurality of aluminum fins to tighten the copper tubes present in the condenser (108). The copper tubes, present in the condenser (108), is configured to provide a free flow to the received hot and pressurized refrigerant gases.
[0047] (d) Evaporator (110): An evaporator (110) used in the present invention is composed of an aluminum coil to prevent the evaporator from rusting. The evaporator (110) is proficient with an up flow passage and a down flow passage to pass the refrigerant through the aluminum coils. In a preferred embodiment, the aluminum coil comprises a cooling BTU of 18000, a suction connection of size of ¾ inch and liquid connection of size 3/8 inch, ensuring an effective cooling of the refrigerant. Further, the evaporator (110) is coupled with another fan that blows the air to extract the heat of the refrigerant from the surrounding of the evaporator (110).
[0048] (e) Plurality of Fans (112): Figure 4 of the present invention illustrates a plurality of industrial fans (112). The low-consumption industrial fans (112) are equipped to facilitate temperature circulation and air uniformity in the system (100). In an exemplary embodiment, the fans equipped in the system (100) are configured to blow cool air across the copper tubes provided in the condenser (108).
[0049] (f) External Power Source (114): An external power source (114) is configured to provide electricity for efficient functioning of all the equipment in the system. Further, the power in the present invention may be extracted from various sources such as, but not limited to, a conventional power source (electricity) and a solar power source, facilitating the conversion of electrical and/ or solar energy into mechanical energy.
[0050] (g) Motor (116): A motor (116) operably coupled with the compressor (106) is actuated through the energy supplied from the external power source.
[0051] (h) Liquid sub-cooler (118): A liquid sub-cooler (118) in the present invention comprises of sub-cooled liquids that lowers the refrigerant inlet temperature of the evaporator (110). The liquid sub-cooler (118) dissipates heat transfer between the evaporator (110) and the compressor (106) via suction and liquid lines. The liquid sub-cooler also helps in decreasing the liquid temperature below the refrigerants’ inlet boiling point.
[0052] (i) Expansion Valve (120): Figure 5 of the present invention illustrates an expansion valve (120) that is configured to remove vapor pressure from liquid refrigerant, and thereby allowing expansion/change of state of refrigerant in the evaporator (110).
[0053] (j) Flash Chamber (122): Figure 6 of the present invention illustrates a flash chamber (122). The flash chamber (122) is a pressure vessel used between the evaporator (110) and the expansion valve (120) to separate refrigerant liquid and vapor at an intermediate pressure. The flash chamber (122) is configured to escape entrapped gases present in the refrigerant and hence increases the efficiency of the system (100).
[0054] (k) Insulation wall (124): The storage chamber (102) of the present invention is insulated with a thick insulating wall that provides enhanced thermal insulation. The thermal insulation provided by the insulation wall (124) reduces the heat transfer between the outdoor air/ atmosphere and the refrigeration unit, which reduces the energy consumption of the refrigeration unit. In an exemplary embodiment, Polyisocyanurate with thermal conductivity of 0.027 W/ (m.K) is configured to be used as an insulation wall (124) to reduce the heat transfer between the atmosphere and the refrigeration unit. The polyisocyanurate ensures better thermal insulation of the storage chamber by preserving the refrigerated product for longer time.
[0055] Further, the insulation wall/ layer (124) is fitted inside the refrigeration system (100) to protect the cold storage from any electric hazard and to minimize the penetration of heat from the outside, so that the energy consumption required to maintain the low temperature inside the chamber remains minimal.
[0056] (l) Heat Exchanger (126): A regenerative heat exchanger (126) configured in the evaporator used in the present invention, is an energy storage device equipped to boost the performance of the system (100) by cyclically transferring heat from gaseous/ vapor refrigerant flowing through the evaporator. In an embodiment, the heat exchanger (126) provided is configured with a copper tubing having a highest working temperature of 250°C, and heat transfer area per plate is 0.058 KW. In an embodiment, the evaporator is installed with a heat exchanger (126) configured with copper tubing to cyclically transfer heat from gaseous/ vapor refrigerant flowing the evaporator.
[0057] (m) Leak proof pipes (128): The refrigeration system (100) of the present invention is equipped with leak proof pipes to connect all components and prevent the leakage from the refrigeration unit. In an embodiment, the pipes (128) include copper tubing with reinforced insulation of 2,000/m.
[0058] (n) Thermostat (130): A thermostat (130) installed in the present invention is configured to continuously monitor the refrigeration system temperature. The thermostat ensures controlled temperature regulation of the refrigerant provided into the system (100).
[0059] In an embodiment of the present invention, a vapor compression regeneration system is powered by at least two external power source such as, but not limited to, electrical outlet and solar power converters. The combination of such power outlets is connected with a motor that converts electrical energy into mechanical energy so as to drive piston/s of the reciprocating compressor.
[0060] Further, the compressor (106) filled with a low pressure R134a refrigerant is compressed by the driving movement of the reciprocating compressor (106) that increases the temperature and vapor pressure of the refrigerant. The refrigerant with high temperature and high pressure is further passed through a copper tubes provided in the condenser (106).
[0061] The condenser (108), on receiving the refrigerant, cools/ lowers the temperature of the refrigerant by converting the high pressurized vapor refrigerant into a liquid state. The liquid refrigerant is further passed through a liquid sub-cooler that lowers the refrigerant inlet temperature and facilitates heat transfer between suction lines and liquid lines, to decrease liquid temperature below the refrigerants’ inlet temperature boiling point.
[0062] The liquid sub-cooler provided in the present invention, is connected with the expansion valve, where the expansion valve (120) ensures to maintain high pressure of the refrigerant on the inlet side and lower pressure on the outlet side. The expansion valve (120) removes the pressure from the liquid refrigerant and passes the liquid refrigerant to the evaporator, through the flash chamber (122). The lower temperature and pressure of the refrigerant enables the evaporator to evaporate the heat and absorb the latent heat of vaporization.
[0063] In another embodiment of the present invention, the system (100) is equipped with a humidifier, which is configured to manipulate the air composition in the surrounding of the storage chamber (102) and to control the air conditioning within the room.
[0064] In an exemplary embodiment, a door (132) installed in the storage chamber (102) is positioned opposite to the fan configured inside the storage room, so as to uniformly circulate air in the storage chamber (102).The fan is installed opposite to the door (132) of the storage chamber (102) to decrease probable energy losses in the system (100), by increasing air pressure inside the chamber (102) and minimizing outside air mixing with the inside air to preserve the chamber's temperature (102).
[0065] In the present invention, a plurality of industrial fans (112) are analytically positioned in the system (100) to circulate the air inside the storage chamber (102). In an exemplary embodiment, at least two fans are positioned near the condenser (108) and evaporator (110) to blow the air across it. The fan positioned near the condenser (108) is configured to flow the air across the copper tubes, whereas the fan positioned near the evaporator (110) is configured blows cool air across the copper coil of the evaporator (110), to completely remove the heat and lower the temperature of the refrigerant. The plurality of fans (112) are positioned in the system (100) to aid maximize circulation throughout the system (100), while preserving the refrigerants’ temperature and uniformity.
[0066] In a preferred embodiment, the vapour compression refrigeration system comprises of a cold chamber (102) comprising a stacking system (104); a compressor (106) connected to the cold chamber (102) is filled with a low pressure R134a refrigerant; a condenser (108) comprising of a plurality of copper tubes is configured to receive the refrigerant from the compressor (106) and converts hot and pressurized refrigerant into a cool liquid refrigerant; a liquid sub-cooler (118) comprising sub-cooled liquids receives the liquid refrigerant from the condenser (108); an expansion valve (120) connected to the liquid sub cooler (118) maintains high pressure of the refrigerant on an inlet side of the expansion valve (120) and lower temperature and pressure on an outlet side of the expansion valve (120); an evaporator (110) connected to the outlet side of the expansion valve (120) receives low temperature and pressure refrigerant via a flash chamber; a plurality of aluminum coils configured in the evaporator (110) comprising an up flow passage and a down flow passage to evaporate the refrigerant into a gaseous form; a plurality of industrial fans (112) analytically positioned in the system (100) to circulate the air inside the storage chamber (102); an external power source (114) to provide power supply to electric components of the system (100); and a motor (116) operably coupled to the compressor (106) is actuated through energy supplied from an external power source. At least one fan installed opposite to a door (132) of the storage chamber (102) to decrease probable energy losses in the system (100), by increasing air pressure inside the chamber (102) and minimizing outside air mixing with inside air so as to preserve temperature of the chamber (102). At least two fans positioned near the condenser (108) and evaporator (110) to blow the air across the condenser (108) and the evaporator (110), wherein the fan positioned near the condenser (108) is configured to flow air across the copper tubes, and the fan positioned near the evaporator (110) is configured to blow air across the aluminum coil of the evaporator (110), so as to completely remove the heat and lower the temperature of the refrigerant.
[0067] In an embodiment figure 7 illustrates a flow diagram of the method of working of ta vapor compression refrigeration system (100) described herein:
I. adding a R134a refrigerant, in gaseous state, into a compressor at low temperature and low pressure;
II. increasing temperature and pressure of the refrigerant by the compressor;
III. entering of the refrigerant into the condenser;
IV. flowing of heat from the condenser to the cooling medium, allowing the vaporized refrigerant to convert into a liquid state/ liquid refrigerant;
V. storing the liquid refrigerant in a liquid receiver unit;
VI. transmitting the liquid refrigerant from the receiver unit to an expansion valve;
VII. reducing pressure of the refrigerant in the expansion valve, to allow vaporization of liquid at a lower temperature in the range of -8°C to -13°C;
VIII. transmitting low temperature refrigerant into an evaporator;
IX. evaporating the refrigerant into the gaseous form through a plurality of aluminum coils provided in the evaporator;
X. absorbing the latent heat of vaporization by the evaporator, which is generated through evaporation;
XI. transmitting the vaporized refrigerant back to the compressor to restart the vapor compression refrigeration cycle.
[0068] In another embodiment of the present invention, at least one fan, i.e. installed in the system, blows/pushes the air in the aluminum coils of the evaporator, to increase the temperature of the aluminum coil. The refrigerant in the evaporator absorbs the heat and converts the refrigerant into the gaseous form. Further, on conversion of the refrigerant into the gaseous form, the refrigerant enters the compressor and restarts the process of vapor compression refrigeration to preserve wide range of perishable foods stored inside the storage chamber (102).
[0069] In an exemplary embodiment of the present invention, the refrigeration components is configured with the following specification and advantages:
Sr. No. Component Specification Advantage
1. Compressor BTU : 17500 - 19000
Voltage : 180 – 220
Reciprocating
Rs. 3800 Relatively cheaper
Simple design and easy to operate
Service life is comparatively higher
Helps decrease the energy expenses drastically compared to other units
2. Evaporator Coil Type : aluminum Coil
Configuration: Upflow / Downflow
Cooling BTU: 18000
Suction Connection Size: 3/4 Inch
Liquid Connection Size: 3/8 Inch
Rs. 30,000 (including coils Evaporators are responsible for the cool air that comes out of the vents
3. Condenser Aluminum Fins tighten the copper tubes to prevent from rust
36X15 inch
Rs. 4800 The refrigerant entering the condenser is hot and pressurized. The condenser then cools the refrigerant by converting it into a liquid state
4. Stacking/Storage Chamber 36.75 m3 volume with 4 level stacking system upto 3m height on each wall Easy usage
5. Leak-proof Pipes 1 in. copper tubing with reinforced insulation: 2,000/m Leak proof and sustainable
6. Air Fans Two fans inside storage for air circulation Circulation and Uniformity
7. Heat Exchangers Copper tubing
2.685 m3 Area
539mm*125mm*115mm
Highest working temperature 250oC
Heat transfer area per plate 0.058 KW
Rs. 18000 Regenerative Part: modification of simple vcrs with addition of a regenerative heat exchanger.
[0070] In another exemplary embodiment of the present invention, Figure 8a to Figure 8f illustrates the component specifications and process parameters of the cold storage chamber. The component specifications of the condensing unit in a cold storage chamber is as follows:
Operating conditions:
Evaporating dew point 265 K
Ambient Temperature 300 K
Evaporating pressure 215700 Pa
Subcooling 3.0 K
Useful Superheat 6.5 K
Additional Subcooling 0 K
Additional superheat 0 K
Return gas temperature 272 K
Rating Conditions Custom
Required cooling capacity (Cooling) 4088 W
COP Cooling 2.48 W
Total Power 1647 W
Total Current 4.433 A
Frequency 50 Hz
Power Supply 380-400 V3 ph
Temperature c 311 K

Mass Flows:
Mass Flow in Evaporator 0.02724 kg/s
Mass flow in compressor 0.02724 kg/s

Technical Specification:
No. of Fans 1
Fan Cow/ Grill Type B2
Condenser Type D7
Air Flow @ 50 Hz (m3/h) 5100
Fan Dimensions 464 mm
Width 1106 mm
Total Height 695 mm
Fan Diameter 457 mm
Fan Blade Size 457 mm
[0071] Figure 8a illustrates the graphical representation of the refrigerants’ cooling capacity in the evaporator. The following table depicts various parameters/ values of the refrigerant in the evaporator:

[0072] Figure 8b illustrates the graphical representation of the power consumption by the refrigerant. The following table depicts power consumed (in watt) by the refrigerant in the system (100):

[0073] Figure 8c illustrates the heating capacity of the refrigerant in a graphical representation. The following table depicts heating capacity (in watt) by the refrigerant in the system (100):

[0074] Figure 8d illustrates the graphical representation of the current capacity (in Amperes) by the refrigerant. The following table depicts the current capacity (in Amperes) by the refrigerant in the system (100):

[0075] Figure 8e illustrates the coefficient of performance (COP) for the refrigerant in a graphical representation. The following table depicts the COP (W/W) for the refrigerant in the system (100):

[0076] Figure 8f illustrates the mass flow of the refrigerant in the system. The following table depicts the mass flow (kg/s) of the refrigerant in the system (100):

[0077] In another exemplary embodiment of the present invention, the component specification of the refrigeration system in liquid state refrigerant is as follows:
Operating conditions (synchronized across application):
Cooling Capacity 4088 W
Mass flow in line 0.02724 kg/s
Healing Capacity 5294 W
Evaporating Temperature 265 K
Condensing Temperature 311 K
Evaporating Pressure 215700 Pa
Condensing Pressure 954400 Pa
Useful superheat 6.5 K
Sub-cooling 3.0 K
Additional superheat 0 K
Additional subcooling 0 K
Discharge Temperature 333 K
[0078] Further, Figure 9 illustrates the system (100) performance curve of the refrigerant in liquid line, based on the above mentioned tables illustrating figures 8a to 8f. The specification/ configuration of the refrigerant in liquid line is illustrated in the below mentioned table:
Line Total:
Pressure Drop 738700 Pa
Saturation Temperature Drop 45.8 K
Pipe. Piping: Copper Pipe DIN-EN 10
Length 1.00 m
Angle 0 deg
Pressure Drop 391.6 Pa
Velocity, in 0.46 m/s
Saturation Temperature Drop 0.0 K
EVR. Solenoid valve: EVR 3 v2 NS 10:
Pressure Drop 13880 Pa
Saturation Temperature Drop 0.5 K
Velocity, in 1.85 m/s
Valve state Open
[0079] In yet another exemplary embodiment of the present invention, the component specification of the refrigeration system in suction state is as follows:

[0080] Figure 10 illustrates the system (100) performance curve of the refrigerant in suction line, based on the above mentioned tables illustrating figures 8a to 8f. The specification/ configuration of the refrigerant in suction line is illustrated in the below mentioned table:


[0081] The advantages of the system of the present invention are discussed herein:
1) The present invention utilizes industrial fans instead of existing modified AC system.
2) The vapor compressor refrigeration system described in this invention increases the efficiency by utilizing a flash chamber and a liquid sub-cooler so as to lower the temperature of the refrigerant.
3) The present invention is provided with a unique stacking chamber for user friendly working.
4) The humidifier provided in the present invention manipulates the air composition in the storage environment to preserve the food product stored in the stacking/ storage chamber for a longer period of time.
5) The door of the present invention is positioned opposite to the position of the fan to reduce the energy losses.
6) The refrigerant used in the present invention have a zero ozone depletion potential.
7) The present invention provides an energy efficient refrigeration system with optimized specific energy consumption (kW/TR).
8) The present invention utilizes a plurality of components and refrigerant exhibiting economical, ecological and cleaner cooling impact on the product.
[0082] While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.
,CLAIMS:WE CLAIM:
1. A vapour compression refrigeration system, comprising:
a. a cold chamber (102) comprising a stacking system (104);
b. a compressor (106) connected to the cold chamber (102) is filled with a low pressure R134a refrigerant;
c. a condenser (108) comprising of a plurality of copper tubes is configured to receive the refrigerant from the compressor (106) and converts hot and pressurized refrigerant into a cool liquid refrigerant;
d. a liquid sub-cooler (118) comprising sub-cooled liquids receives the liquid refrigerant from the condenser (108)
e. an expansion valve (120) connected to the liquid sub cooler (118) maintains high pressure of the refrigerant on an inlet side of the expansion valve (120) and lower temperature and pressure on an outlet side of the expansion valve (120);
f. an evaporator (110) connected to the outlet side of the expansion valve (120) receives low temperature and pressure refrigerant via a flash chamber;
g. a plurality of aluminum coils configured in the evaporator (110) comprising an up flow passage and a down flow passage to evaporate the refrigerant into a gaseous form;
h. a plurality of industrial fans (112) analytically positioned in the system (100) to circulate the air inside the storage chamber (102);
i. an external power source (114) to provide power supply to electric components of the system (100);
j. a motor (116) operably coupled to the compressor (106) is actuated through energy supplied from an external power source;
wherein,
at least one fan installed opposite to a door (132) of the storage chamber (102) to decrease probable energy losses in the system (100), by increasing air pressure inside the chamber (102) and minimizing outside air mixing with inside air so as to preserve temperature of the chamber (102);
at least two fans positioned near the condenser (108) and evaporator (110) to blow the air across the condenser (108) and the evaporator (110), wherein the fan positioned near the condenser (108) is configured to flow air across the copper tubes, and the fan positioned near the evaporator (110) is configured to blow air across the aluminum coil of the evaporator (110), so as to completely remove the heat and lower the temperature of the refrigerant;
2. The system as claimed in claim 1, wherein the liquid sub-cooler (118) dissipates heat transfer between the evaporator (110) and the compressor (106) via a plurality of suction and liquid lines.
3. The system as claimed in claim 1, wherein the expansion valve (120) removes vapor pressure from the liquid refrigerant received from the condenser (108), so as to allow expansion/change of state of refrigerant.
4. The system as claimed in claim 1, wherein the system (100) comprises a flash chamber (122) installed between the evaporator (110) and the expansion valve (120) to separate refrigerant liquid and vapor of the refrigerant.
5. The system as claimed in claim 1, wherein the plurality of fans (112) blow air to extract heat of the refrigerant from the surrounding of the evaporator (110).
6. The system as claimed in claim 1, wherein the evaporator (110) is installed with a heat exchanger (126) configured with copper tubing to cyclically transfer heat from gaseous/ vapor refrigerant flowing the evaporator.
7. The system as claimed in claim 1, wherein the system (100) is equipped with leak proof pipes to connect all components and prevent the leakage from the refrigeration unit.
8. A method of working of vapour compression refrigeration system (100), comprising:
I. adding a R134a refrigerant, in a gaseous state, into a compressor at a low temperature and pressure;
II. increasing temperature and pressure of the refrigerant by a compressor;
III. entering of the refrigerant into the condenser;
IV. flowing of heat from the condenser to a cooling medium, allowing the vaporized refrigerant to convert into a liquid state/ liquid refrigerant;
V. storing the liquid refrigerant in a liquid receiver unit;
VI. transmitting the liquid refrigerant from a receiver unit to an expansion valve;
VII. reducing pressure of the refrigerant in the expansion valve, to allow vaporization of the liquid at a low temperature in the range of -8°C to -13°C;
VIII. transmitting low temperature refrigerant into an evaporator;
IX. evaporating the refrigerant into a gaseous form through a plurality of aluminum coils provided in the evaporator;
X. absorbing latent heat of vaporization by the evaporator, which is generated through evaporation;
XI. transmitting the vaporized refrigerant back to the compressor for next of vapor compression refrigeration cycle.

9. The method as claimed in claim 8, wherein at least one fan blows/pushes air in the aluminum coils of the evaporator to increase the temperature of the aluminum coil and convert the refrigerant into the gaseous form.

10. The method as claimed in claim 8 and claim 9, wherein the gaseous form of the refrigerant enters the compressor and starts next vapor compression refrigeration cycle, so as to preserve wide range of perishable foods stored inside the storage chamber (102).