DESIGN AND FABRICATION OF VCR SYSTEM USING BLEND OF HC and HFC REFRIGERANT

Domestic refrigerators are working on the basic vapor compression cycle using only a single refrigerant in them as a working fluid. Previously, the CFCs refrigerants are used as a refrigerant in VCR systems but due to their high effects on the environment, they are replaced by HFCs refrigerants like

Project Title

DESIGN AND FABRICATION OF VCR SYSTEM USING BLEND OF HC and HFC REFRIGERANT

Project Area of Specialization

Mechanical Engineering

Project Summary

Domestic refrigerators are working on the basic vapor compression cycle using only a single refrigerant in them as a working fluid. Previously, the CFCs refrigerants are used as a refrigerant in VCR systems but due to their high effects on the environment, they are replaced by HFCs refrigerants like R-134a. HFCs refrigerants are not environmentally friendly. Most of the researches shows that HC refrigerants like R-600a & R290a can be replaced in the VCR system and they are more efficient than CFCs & HFCs refrigerant.  HC refrigerants are dangerous under working conditions because they are working on high pressure and due to their high flammability, they are not reasonable in domestic use refrigerators. The flammability of the HCs refrigerants can be reduced by mixing them with non-flammable HFCs refrigerants.

We shall use the LPG/R-134a blend of the refrigerant with a different mass fractions under the same working conditions. As LPG pull-down time is less than of the R-134a that it requires less time to gain the desired temperature. Where LPG gives better performance in the VCR system then R-134a. The cooling capacity of the LPG is higher than that of R-134a and LPG consumes less energy input to the compressor. So, the risk of flammability can be reduced using the blend of LPG/R-134a refrigerant. Blend of the refrigerant enhance the performance of the VCR system and more compatible. So, LPG/R-134a blend gives higher performance than R-134a under the same conditions. The optimize calculation of the component will be used by changing the mass fraction of the blend to get better performance the blend gives higher performance with capillary tube length 5.1m. We also work to design and fabricate the gas blending chamber to get an accurate blend of refrigerants with precise mass fraction and then blend from the chamber is used in the VCR system.

The optimization of energy consumption by compressor, coefficient of performance (COP), and the and pull-down time are the factors that are under consideration to get a better result by using blend LPG/R-134a refrigerant instead of a single refrigerant R-134a on the same conditions.

Principal investigator has worked in field of Refrigeration and Air conditioning. My last project was” Investigate the COP of VCRS system with or without graphene-coated condenser”. He has worked in synthesis of nano refrigerant for excellent performance of VCRS system. 

Co-principal Investigator has worked in the field of automation and controlling mechanism for refrigeration cycle and electronics involved in designing and controlling of different parts to enhance performance of VCRS.

Project Objectives

The aim of this project to analyses the performance of VCR (vapor compression refrigeration) system. The main objectives of this project are

1. To design and fabricate the system for accurate and precise blending of gas with desirable ratio of R134a/LPG.
2. To design and fabricate VCR system & determine the COP of VCR system by using R-134a/LPG as a refrigerant

Project Implementation Method

The basic design of the project contains all basic vapor compression cycle components and some additional components for testing. A proper mixture of the refrigerants R-134a and LPG charged in the system from the mixing chamber. The cycle starts from the compressor which pressurizes the refrigerant. According to the power need to run the system 1/4 hp compressor is optimized for usage. Pressurized refrigerant goes toward the condenser from the exhaust of compressor a high-pressure gauge measures the outlet pressure and the temperature is measured by a PT-100 thermocouple placed in between of compressor outlet and condenser inlet. The condenser rejects the heat from the refrigerant to the atmosphere. Tube and fine type condenser is used with 13.2m length and 10mm outer diameter of the tube.

A condenser fan is placed that through the air on condenser which maximizes the heat transfer in the condenser. To measure the pressure at the outlet of the condenser a high-pressure gauge is placed, and the temperature is measured by a thermocouple. Due to the change in pressure and temperature variation, there should be a possibility that refrigerant may change its volumetric properties. To overcome this issue a receiver is placed in the way to the expansion valve that ensures the proper mixture of blend proceed further and convert remaining vapor contents into liquid. After the receiver, a rotameter is used to measure the flow rate of the outgoing refrigerant to the expansion valve. A filter drier is also used here to filter the refrigerant because the expansion valve is basically a narrow tube known as a capillary tube.

The optimized length of the capillary tube for this project is 5.1m. When the refrigerant passes through the capillary tube the pressure decreases and at the outlet of the tube sudden expansion occur that produces a cooling effect. A low-pressure gauge measures the pressure there and thermocouple measure the temperature. To produce refrigeration effect refrigerant pass through the evaporator of 3.05m length and tube outer diameter of 10mm. Again, a low-pressure gauge measures the pressure there and the temperature is measured by a thermocouple. Overall four pressure gauges and four PT-100 thermocouples are placed in the system at different points. A proposed system layout is placed in .

So, the project is based on the fabrication of two systems first to fabricate a mixing chamber for the refrigerant and design and fabrication of VCRS that use R-134a/LPG as a blend refrigerant.

For calculation of COP a adiabatic chamber is designed. Which consist of insulated walls , heater to supply heat and a stirrer to for homogenous heat transfer. The cooling effect of the compressor on evaporator will be cancel out by heater. Brine solution is also placed in the chamber for maximum heat transfer.

Benefits of the Project

1. Reduce the energy consumption by the compressor in VCR cycle.
2. Fabricate a VCR system which is more environmentally acceptable and more efficient
3. Better COP than R-134a under same conditions
4.  A safe VCR system using HC refrigerants
5. Reduce global warming and zero ozone depletion.

Technical Details of Final Deliverable

This project deals with the design & fabrication of a vapor compression refrigeration system (VCRS utilizing the blend of R134a and LPG with a distinctive mass ratio as an option to R134a. In this project, we shall analyze the energy consumption of the two refrigerants, R134a/LPG and R134a, in a checked vapor pressure refrigeration system using the same operating conditions. The System with blend of R134a and LPG will be tested by varying the mass fraction with testing on the same operating conditions. Comparison of the blend system will be made by taking refrigerant R134a as standard. The main factors in this project are energy consume by the compressor, pull-down by the system and COP. The blended refrigerant R134a/LPG proposed to be a fitting long-haul possibility to supplant R134a as a new age VCRs, because of its good refrigeration properties and environmentally friendly nature blend of the blend.

Final Deliverable of the Project

Hardware System

Core Industry

Energy

Other Industries

Others

Core Technology

Clean Tech

Other Technologies

Others

Sustainable Development Goals

Good Health and Well-Being for People, Affordable and Clean Energy, Industry, Innovation and Infrastructure

Required Resources

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