A Hybrid Absorption System With Generator Level Optical Control and Variable Flow Rate

2019 ◽  
Author(s):  
Gleidson Souza ◽  
José V. C. Vargas ◽  
Wellington Balmant ◽  
Marcos C. Campos ◽  
Leonardo C. Martinez ◽  
...  
Keyword(s):  
Control System ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Air Conditioning ◽  
Energy Input ◽  
Waste Heat ◽  
Optical Control ◽  
Working Fluid ◽  
Vapor Compression ◽  
Regenerative Heat

Abstract Current refrigeration and air conditioning systems are mostly based on the vapor compression cycle, which require electrical energy input. Absorption systems have gained new interest due to the possibility of utilizing waste heat as energy input. In addition, the environmental impact generated by such systems is recognized as much smaller than vapor compression systems. Therefore, this work developed and characterized an absorption refrigeration system with an innovative generator level optical control and variable working fluid mass flow rate, with potential for use in industrial, commercial and residential heating, ventilation, air conditioning, and refrigeration (HVAC & R) systems. The system is hybrid, since it was designed to be fed with heat from the burning of different fuels and/or waste heat sources in complementary fashion. The system consists of: a condenser, an evaporator, two expansion valves, two absorbers, a centrifugal pump, a regenerative heat exchanger, a generator, a rectifier, a generator level optical control system, and two liquid accumulators. The developed level control system consists of 3 light Dependent Resistors (LDR) positioned inside a box built around a transparent level meter, and illuminated internally by a low power light bulb. A frequency inverter and a centrifugal pump allow for the working fluid solution inside the generator to be within a safe range for efficient cooling cycle operation. The system measured refrigeration capacity rate was 2.3 TR, which qualifies as a good performance, since the equipment was originally designed for 1 TR.

Thermodynamic Analysis and Working Fluid Optimization of a Combined ORC-VCC System Using Waste Heat From a Marine Diesel Engine

2014 ◽  
Author(s):  
Oumayma Bounefour ◽  
Ahmed Ouadha
Keyword(s):  
Thermodynamic Analysis ◽  
Waste Heat ◽  
Operating Conditions ◽  
Working Fluid ◽  
Vapor Compression ◽  
Marine Diesel ◽  
Vapor Compression Refrigeration ◽  
Propylene Yield ◽  
Fluid Optimization ◽  
Propane Butane

This paper examines through a thermodynamic analysis the feasibility of using waste heat from marine Diesel engines to drive a vapor compression refrigeration system. Several working fluids including propane, butane, isobutane and propylene are considered. Results showed that isobutane and Butane yield the highest performance, whereas propane and propylene yield negligible improvement compared to R134a for operating conditions considered.

A Study on the Combined Driven Refrigeration Cycle Using Ejector

2021 ◽  
pp. 2150004
Author(s):  
Waseem Raza ◽  
Gwang Soo Ko ◽  
Youn Cheol Park
Keyword(s):  
Air Conditioning ◽  
Waste Heat ◽  
Primary Source ◽  
Mechanical Efficiency ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Working Fluid ◽  
Low Grade ◽  
Refrigeration Cycle ◽  
R 134A

The rising need for thermal comfort has resulted in a rapid increase in refrigeration systems’ usage and, subsequently, the need for electricity for air-conditioning systems. The ejector system can be driven by a free or affordable low-temperature heat source such as waste heat as the primary source of energy instead of electricity. Heat-driven ejector refrigeration systems become a promising solution for reducing energy consumption to conventional compressor-based refrigeration technologies. An air-conditioning system that uses the ejector achieves better performance in terms of energy-saving. This paper presents a study on the combined driven refrigeration cycle based on ejectors to maximize cycle performance. The experimental setup is designed to determine the coefficient of performance (COP) with ejector nozzle sizes 1.8, 3.6, and 5.4[Formula: see text]mm, respectively. In this system, the R-134a refrigerant is considered as a working fluid. The results depict that the efficiency is higher than that of the conventional refrigeration method due to comparing the performance of the conventional refrigeration cycle and the combined driven refrigeration cycle. The modified cycle efficiency is better than the vapor compression cycle below 0∘C, which implies sustainability at low temperatures by using low-grade thermal energy. For the improvement of mechanical efficiency, proposed cycle can be easily used.

Review on Solar Powered Desiccant Wheel Cooling System

2017 ◽  
Vol 9 (01) ◽  
pp. 31-34
Author(s):  
Khushboo Singh
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Good Alternative ◽  
Energy Utilization ◽  
Working Fluid ◽  
Low Grade ◽  
Vapor Compression ◽  
Air Conditioning System ◽  
Desiccant Wheel ◽  
Solar Powered

Nowadays, there is still a big amount of needs in air conditioning system with environmental change and improvement of living standards. However, air conditioning system have already accounted for a large part of energy consumption in the whole society, and then how to effectively increase the energy utilization. Desiccant wheel cooling system operate on the principle of adsorption dehumidification and evaporate cooling. The system adopts natural substance as working fluid and can be driven by low grade thermal energy such as solar energy. Due to this merit, solar powered desiccant wheel cooling system has recognized as one of good alternative to conventional vapor compression air conditioning system and has obtained increasing interest in the past years. This review paper aims to summarize recent research development related to solar powered desiccant wheel cooling system and to provide information for potential application. The cooling potential of the system is based on the performance of the desiccant wheel that removes humidity from outside air to increase the potential of the humidifier.

A Passive, Vapor Compression Refrigerator for Solar Cooling

1990 ◽  
Vol 112 (3) ◽  
pp. 191-195 ◽  
Author(s):  
R. I. Loehrke
Keyword(s):  
Heat Pipe ◽  
Waste Heat ◽  
Freezing Point ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Thermal Coefficient ◽  
Vapor Compression ◽  
Solar Cooling ◽  
Theoretical Considerations ◽  
Operating Temperature Range

A new, completely passive, vapor compression refrigerator is described in this paper. This refrigerator combines elements of the heat pipe and the vapor jet refrigerator and is referred to here as a heat pipe refrigerator. It may be driven with heat from low temperature solar collectors or with industrial waste heat and used to provide cooling. Compression work is provided by gas dynamic processes and liquid pumping may be obtained using gravitational or capillary forces. No power is required for operation. The device has no moving parts and may be externally similar to a heat pipe with three heat transfer zones. The working fluid is chosen to match the desired operating temperature range. Water, at subatmospheric pressure, is an appropriate fluid for operation around room temperature. Theoretical considerations indicate that the thermal coefficient of performance of the heat pipe refrigerator will depend strongly on the magnitude of the temperature differences over which it is designed to operate. Results from a laboratory test confirm the concept and demonstrate cooling down to the freezing point using water vapor at 51°C to drive the device and with heat rejection at 18°C.

Energy Savings in Air Conditioning System Using Ejector: An Overview

2014 ◽  
Vol 493 ◽  
pp. 93-98 ◽  
Author(s):  
Kasni Sumeru ◽  
Luga Martin ◽  
Farid Nasir Ani ◽  
Henry Nasution ◽  
Farid Nasir Ani
Keyword(s):  
Air Conditioning ◽  
Energy Savings ◽  
Waste Heat ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Air Conditioning System ◽  
Vapor Compression Refrigeration Cycle ◽  
Performance System ◽  
Vapor Compression Refrigeration ◽  
Save Energy

There are two ejector configurations described in the present study: ejector refrigeration cycle and the ejector as an expansion device. The use of waste heat from the car engine and industry as a heat-driven energy for air conditioning system in automobile and building can save energy. Although the ejector refrigeration cycle has a low COP, the use of waste heat as a heat-driven energy incurs a lower operational cost compared with vapor compression refrigeration system. In addition, an ejector as an expansion device can be applied in the vapor compression refrigeration cycle to improve the performance system.

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