Improvement of COP with Heat Recovery Scheme for Solar Adsorption Cooling System

2018 ◽  
Vol 26 (02) ◽  
pp. 1850016 ◽  
Author(s):  
K. M. Ariful Kabir ◽  
Rifat A. Rouf ◽  
M. M. A. Sarker ◽  
K. C. Amanul Alam ◽  
Bidyut B. Saha
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Cooling System ◽  
Continuous System ◽  
Recovery Process ◽  
Coefficient Of Performance ◽  
Heat Transfer Fluid ◽  
Adsorption Refrigeration ◽  
Adsorption Chiller ◽  
Adsorption Cooling System

Heat recovery ensures optimum usage of the collected energy, and thus, minimizes heat loss for a solar adsorption chiller. Two-bed adsorption chiller with conventional single stage, run by direct solar coupling with heat recovery, has been studied mathematically. In a heat recovery adsorption refrigeration system, to facilitate heat transfer, heat transfer fluid is distributed between two adsorbers maintaining the same mass flow rate. There is no mass transfer between system components during this phase. It is a semi-continuous system performed between two adsorption beds. After completion of desorption/condensation mode, heat transfer fluid is allowed to circulate between the heated desorber and the cooled adsorber. This process distributes some heat of the desorption bed to the adsorber preparing it for the next preheating mode where heat transfer between them is done adiabatically. Consequently, the performance has been checked and a satisfactory increase in the Coefficient of Performance (COP) (approximately 15%) has been detected in the calculated results for the heat recovery operation. It is also observed that the heat recovery process enhances the working hour and overall performances of the solar heat driven adsorption chiller.

scholarly journals Study and Analysis by Numerical Simulation of a Solar Continuous Adsorption Chiller

2015 ◽  
Vol 773-774 ◽  
pp. 605-609
Author(s):  
Rabah Gomri ◽  
Billel Mebarki
Keyword(s):  
Solar Energy ◽  
Cooling System ◽  
Recovery Process ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Solar Collectors ◽  
Adsorption Refrigeration ◽  
Continuous Adsorption ◽  
Adsorption Cooling System ◽  
Mass Recovery

Environment and energy problems over the world have motivated researchers to develop energy systems more sustainable, having as one of the possible alternative the use of solar energy as source for cooling systems. Adsorption refrigeration systems are regarded as environmentally friendly alternatives to conventional vapour compression refrigeration systems, since they can use refrigerants that do not contribute to ozone layer depletion and global warming. In this paper a performance comparison between a solar continuous adsorption cooling system without mass recovery process and solar continuous adsorption cooling system with mass recovery process is carried out. Silica-Gel as adsorbent and water as refrigerant are selected. The results show that the adsorption refrigeration machine driven by solar energy can operate effectively during four months and is able to produce cold continuously along the 24 hours of the day. The importance of the mass recovery is proved in this study by increasing the coefficient of performance and the cooling capacity produced. For the same cooling capacity produced, the required number of solar collectors with mass recovery system is lower than the required number of solar collectors in the case of the refrigeration unit without mass recovery. For the same cooling capacity the system with mass recovery process allowed lower generation temperature.

Study of the Effects of Mass and Heat Recovery on the Performances of Activated Carbon/Ammonia Adsorption Refrigeration Cycles

2002 ◽  
Vol 124 (3) ◽  
pp. 283-290 ◽  
Author(s):  
T. F. Qu ◽  
W. Wang ◽  
R. Z. Wang
Keyword(s):  
Activated Carbon ◽  
Working Conditions ◽  
Heat Recovery ◽  
Recovery Process ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Adsorption Refrigeration ◽  
Ammonia Adsorption ◽  
Mass Recovery

Mass recovery can play an important role to better the performance of adsorption refrigeration cycles. Cooling capacity can be significantly increased with mass recovery process. The coefficient of performance (COP) of the activated carbon/ammonia adsorption refrigeration cycle might be increased or decreased with mass recovery process due to different working conditions. The advantage is that its COP is not sensitive to the variation of heat capacity of adsorber metal and condensing and evaporating temperature. The cycle with mass and heat recovery has a relatively high COP.

Heat Recovery Time of Adsorption Cooling System

2018 ◽  
Vol 26 (02) ◽  
pp. 1850014 ◽  
Author(s):  
Xuan Quang Duong ◽  
Ngoc Vi Cao ◽  
Jae Dong Chung
Keyword(s):  
Recovery Time ◽  
Heat Recovery ◽  
Cooling System ◽  
Recovery Process ◽  
Finned Tube ◽  
Hot Water ◽  
Two Dimensional ◽  
Cycle Times ◽  
Tube Type ◽  
Adsorption Cooling System

In this study, a two-dimensional numerical model of finned-tube type adsorbers was developed and used to examine heat recovery time to improve the performance of an adsorption cooling system. The optimal heat recovery time, which resulted in the highest COP, was determined for a range of heat source temperatures (60–90[Formula: see text]C) and cycle times (600–1200[Formula: see text]s). The introduced heat recovery process enhanced COP, but also reduced SCP. This penalty became more serious when the hot water temperature was low and cycle time was short, which serves as a guideline for when heat recovery should be adopted in a given operating condition.

scholarly journals Preliminary Results on Experimental Modelling of an Adsorption Chiller

2021 ◽  
Vol 6 ◽  
pp. 29
Author(s):  
Nayrana Daborer-Prado ◽  
Alois Resch
Keyword(s):  
Numerical Model ◽  
Water Cycle ◽  
Cooling System ◽  
Numerical Study ◽  
Lumped Parameter Model ◽  
Coefficient Of Performance ◽  
Adsorption Refrigeration ◽  
Experimental Modelling ◽  
Adsorption Chiller ◽  
Lumped Parameter

Adsorption refrigeration, as a renewable cooling method, has received more attention in the last few years. The interest in this technology comes especially from developing and tropical countries, where the demand for cooling increases every year due to economy and population growth. Based on this scenario, this work aims to develop a numerical model of an adsorption chiller driven with solar energy, which can be used to optimize the cooling system operation of the building where the device is situated and compare it with the current cooling methods in use. The numerical study here presented was created using Matlab/Simulink™, it is based on a lumped parameter model that relies on physical properties and represents a cooling system using a pair of silica gel-water in a two-bed chiller. In this study, the authors proposed a simplified version of the system and the numerical model, which aims to reduce the simulation time and provide faster results. Besides the temperatures in the system, which range from 52 °C to 72 °C in the hot cycle and 12 °C to 23 °C in the chilled water cycle, the results also include the variation of water uptake in the two adsorbent beds. In general, the simulated temperature, cooling and heating power and coefficient of performance (COP) are in fair agreement with the literature data, nevertheless, the final results show that improvements still have to be performed.

Simulation Study of the Heat and Mass Recovery on the Performance of Adsorption Cooling Systems

2014 ◽  
Author(s):  
K. C. Chan ◽  
C. Y. Tso ◽  
Christopher Y. H. Chao
Keyword(s):  
System Performance ◽  
Heat Recovery ◽  
Cooling System ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Cooling Systems ◽  
Heating And Cooling ◽  
Adsorption Cooling System ◽  
Heat And Mass Recovery ◽  
Mass Recovery

In this study, simulation was conducted to investigate the effect of mass recovery, heat recovery, pre-heating and pre-cooling time on the system performance of a double-bed adsorption cooling system. Pressures of different system components were considered in the simulation. The adsorbent-adsorbate pair used was silica-gel and water. The heating and cooling temperatures were selected to be 85°C and 27°C respectively. Both the adsorption and desorption phase times were set at 15 minutes. The coefficient of performance (COP) and specific cooling power (SCP) were used to quantify the performance of the system. From the simulation, the basic cycle provided COP and SCP of 0.20 and 40.9W/kg respectively. By conducting heat recovery for 120 seconds, the system COP was largely increased by 99% to 0.40 compared to the basic cycle. The SCP was also increased to 42.3W/kg. Mass recovery, however, did not have too much effect on the system performance. The COP and SCP only increased by 4.5% and 3.9% respectively when conducting mass recovery for 4.7 seconds. For conducting heat and mass recovery, the COP and SCP were increased to 0.36 and 44.68W/kg, respectively. Pre-heating and pre-cooling can also be beneficial in improving both COP and SCP. The COP and SCP were increased by 14.5% and 10.1% respectively, to 0.23 and 45.0W/kg by conducting pre-heating and pre-cooling for 50.3 seconds. The combinations of these processes were also studied. It is suggested heat and mass recovery then pre-heating and pre-cooling should be conducted to improve COP and SCP. The improvements showed 31.2% for COP, increasing to 0.27, and 11.9% for SCP, increasing to 45.7W/kg.

scholarly journals Simulation of Minichannel Liquid Based Thermoelectric Cooling System by Changing Dimension of Minichannel and Type of Heat Transfer Fluid

2021 ◽  
Vol 9 (9) ◽  
pp. 972-978
Author(s):  
Soheb Khan Sayeed Khan
Keyword(s):  
Heat Transfer ◽  
Integrated Circuits ◽  
Cooling System ◽  
Heat Removal ◽  
Coefficient Of Performance ◽  
Heat Transfer Fluid ◽  
Peltier Effect ◽  
Thermoelectric Cooling ◽  
Central Processing ◽  
Low Efficiency

Abstract: In recent time, due to exponential growth in electronic devices there is significant increase in heat dissipating element like integrated circuits(IC), graphical 2Assistant Professor, processing units (GPU) and central processing units (CPU). If there is no proper arrangement for heat removal it can permanently damage whole system. There are several methods used for this, one of which is thermoelectric cooling which works on peltier effect, thermoelectric devices with proper cooling arrangement act like heat pump which removes heat from one side and provide it to another side. The drawback of this system is low efficiency. In this project CFD analysis is done for minichannels of different dimensions along with thermoelectric. Simulation is performed by changing parameters such as hydraulic diameter of minichannel, changing type of heat transfer fluid and mass flow rate of fluid. The study reveals that by optimizing these parameters performance of thermoelectric system can be improved. The aim of this study is to optimize these parameters in order to improve overall heat transfer coefficient and coefficient of performance of the system. Keywords: Thermoelectric cooling, Peltier effect, Minichannel, Overall heat transfer, CFD

scholarly journals Numerical Evaluation of a HVAC System Based on a High-Performance Heat Transfer Fluid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3298
Author(s):  
Gianpiero Colangelo ◽  
Brenda Raho ◽  
Marco Milanese ◽  
Arturo de Risi
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Cooling System ◽  
Electrical Energy ◽  
Simulation Software ◽  
Heat Transfer Fluid ◽  
Hvac System ◽  
Dynamic Simulations ◽  
Heating And Cooling ◽  
The University

Nanofluids have great potential to improve the heat transfer properties of liquids, as demonstrated by recent studies. This paper presents a novel idea of utilizing nanofluid. It analyzes the performance of a HVAC (Heating Ventilation Air Conditioning) system using a high-performance heat transfer fluid (water-glycol nanofluid with nanoparticles of Al2O3), in the university campus of Lecce, Italy. The work describes the dynamic model of the building and its heating and cooling system, realized through the simulation software TRNSYS 17. The use of heat transfer fluid inseminated by nanoparticles in a real HVAC system is an innovative application that is difficult to find in the scientific literature so far. This work focuses on comparing the efficiency of the system working with a traditional water-glycol mixture with the same system that uses Al2O3-nanofluid. The results obtained by means of the dynamic simulations have confirmed what theoretically assumed, indicating the working conditions of the HVAC system that lead to lower operating costs and higher COP and EER, guaranteeing the optimal conditions of thermo-hygrometric comfort inside the building. Finally, the results showed that the use of a nanofluid based on water-glycol mixture and alumina increases the efficiency about 10% and at the same time reduces the electrical energy consumption of the HVAC system.

Continuous Operating Elastocaloric Heating and Cooling Device: Air Flow Investigation and Experimental Parameter Study

2019 ◽  
Author(s):  
Susanne-Marie Kirsch ◽  
Felix Welsch ◽  
Lukas Ehl ◽  
Nicolas Michaelis ◽  
Paul Motzki ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Air Flow ◽  
Experimental Parameter ◽  
Rotation Frequency ◽  
Coefficient Of Performance ◽  
Large Temperature ◽  
Parameter Study ◽  
Or Efficiency ◽  
Heating And Cooling

Abstract Elastocaloric cooling uses solid-state NiTi-based shape memory alloy (SMA) as a non-volatile cooling medium and enables a novel environment-friendly cooling technology without global warming potential. Due to the high specific latent heats activated by mechanical loading/unloading, large temperature changes can be generated in the material. Accompanied by a small required work input, a high coefficient of performance is achievable. Recently, a fully-functional and illustrative continuous operating elastocaloric fluid cooling system based on SMA is developed and realized, using a novel mechanical concept for individual loading and unloading of multiple SMA wire bundles. The fluid-based heat transfer system is designed for efficient heat exchange between the stationary heat source/sink and the SMA elements, operates without any additional heat transfer medium. Rotation frequency and fluid flow-rate are adjustable during operation, which allows adapting the operation point to power- or efficiency-optimized demands. The versatile placement of the in- and outlets allows different duct lengths and counter-flow or parallel-flow experiments. To investigate the air flow parameters at the in- and outlets, as well as the crossflow between the hot and cold side, a measurement system is developed and integrated. In this contribution, the first measurement results of the output temperatures for inlet air flow variation in combination with different rotation frequencies are presented.

scholarly journals Performance Assessment of a Heat Recovery System for Monolithic Receiver-Reactors

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Stefan Brendelberger ◽  
Philipp Holzemer-Zerhusen ◽  
Henrik von Storch ◽  
Christian Sattler
Keyword(s):  
Heat Transfer ◽  
Energy Demand ◽  
Heat Recovery ◽  
Heat Transfer Fluid ◽  
Storage Unit ◽  
Thermochemical Cycles ◽  
Temperature Swing ◽  
Recovery System ◽  
Heat Recovery System ◽  
Material Studies

The most advanced solar thermochemical cycles in terms of demonstrated reactor efficiencies are based on temperature swing operated receiver-reactors with open porous ceria foams as a redox material. The demonstrated efficiencies are encouraging but especially for cycles based on ceria as the redox material, studies have pointed out the importance of high solid heat recovery rates to reach competitive process efficiencies. Different concepts for solid heat recovery have been proposed mainly for other types of reactors, and demonstration campaigns have shown first advances. Still, solid heat recovery remains an unsolved challenge. In this study, chances and limitations for solid heat recovery using a thermal storage unit with gas as heat transfer fluid are assessed. A numerical model for the reactor is presented and used to analyze the performance of a storage unit coupled to the reactor. The results show that such a concept could decrease the solar energy demand by up to 40% and should be further investigated.

Performance Analysis of a Silica Gel-Water Adsorption Cooler: Impact of Nanofluids on Cooler Performance and Size

2015 ◽  
Author(s):  
I. P. Koronaki ◽  
M. T. Nitsas ◽  
E. G. Papoutsis ◽  
V. D. Papaefthimiou
Keyword(s):  
Heat Transfer ◽  
Silica Gel ◽  
Cooling Capacity ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Theoretical Research ◽  
Adsorption Chiller ◽  
Heat Transfer Fluids ◽  
Thermally Driven ◽  
Sorption Heat

Thermally driven chillers also known as sorption heat pumps have drawn considerable attention in recent years. They can be divided into two main categories: absorption (liquid-vapor) and adsorption (solid-vapor) systems. Even though adsorption cycles have relatively lower coefficient of performance compared to absorption cycles, however they prevail in terms of heat source, electric consumption for moving parts, crystallization etc. In order to overcome the drawback of low COP and specific cooling capacity, nanofluids, i.e. mixtures of nanometer size particles well-dispersed in a base fluid, can be used as heat transfer fluids as recent experimental and theoretical research has proved that nanofluids can exhibit a significant increase on heat transfer. In this study a two bed, single-stage adsorption chiller which utilizes the silica gel-water pair as adsorbent-refrigerant is simulated. The cooling capacity and the COP of the chiller are calculated for various cycle times. The usage of nanofluids as heat transfer fluids in the chiller evaporator and condenser and their effect on chiller performance and size is investigated. It is proved that the presence of nanofluids at different volume concentrations will enhance the cooling capacity and the COP of the adsorption chiller and therefore will lead to smaller, in terms of size, heat exchangers.

Sign in / Sign up

Export Citation Format

Share Document