scholarly journals Numerical study of a Solar Absorption Refrigeration Machine

2020 ◽  
Vol 150 ◽  
pp. 01009
Author(s):  
J. Dardouch ◽  
M. Charia ◽  
A. Bernatchou
Keyword(s):  
Distillation Column ◽  
Operating Temperature ◽  
Numerical Study ◽  
Heating System ◽  
Coefficient Of Performance ◽  
List Type ◽  
Absorption Refrigeration ◽  
Solar Collectors ◽  
Solar Absorption ◽  
Refrigeration Machine

In this paper, we present a numerical study of a single-stage absorption refrigeration machine, operating with a couple of water-ammonia fluids, equipped with a distillation column and associated with a solar heating system using solar collectors. The study has showed the benefit of using the distillation column which is manifested by: The decrease of the operating temperature, The improvement of the coefficient of performance, Surface reduction of the solar collectors, The improvement of the solar coefficient of performance. The solar study shows that the absorption refrigeration machine equipped with a distillation column is better suited to solar energy with significantly better performance compared to the simple absorption refrigeration machine.

Experience With a Solar Heating ATES System for a University Building

1994 ◽  
Vol 116 (2) ◽  
pp. 88-93 ◽  
Author(s):  
E. Hahne ◽  
M. Hornberger
Keyword(s):  
Solar Energy ◽  
Heat Pump ◽  
Waste Heat ◽  
Heating System ◽  
Solar Heating ◽  
Coefficient Of Performance ◽  
Solar Collectors ◽  
Power Station ◽  
Heat Demand ◽  
Heat Store

At Stuttgart University, a solar heating system for an office building with laboratories and lecture rooms was installed in 1985. It consists of 211 m2 of unglazed solar collectors, a 1050 m3 water-flooded pebble bed heat store, and a heat pump. Heat can be supplied to the store from the solar collectors or from a power station (as waste heat). The whole system has worked successfully for five years under varied strategies. In the first two heating periods, the heating strategy was aimed to collect as much solar energy as possible. Thus, about 60 percent of the heat demand could be covered by solar energy; but the yearly heat pump coefficient of performance (COP) was only around 2.76. With an improved heat pump, a monthly COP of 3.6 was obtained. Heat losses from the storage amounted to about 20 percent.

The Possibility of Using the Ground as a Seasonal Heat Storage: The Numerical Study

2004 ◽  
Author(s):  
Pawel Olszewski
Keyword(s):  
Solar Energy ◽  
Heat Storage ◽  
Numerical Study ◽  
Storage System ◽  
Heating System ◽  
Numerical Code ◽  
Space Heating ◽  
Solar Collectors ◽  
Seasonal Heat ◽  
The One

Humankind can effectively utilize only part of the solar energy reaching a surface of the Earth. It is due to the low density of the solar radiation and its unfavorable distribution. The majority of solar energy falls to the low latitude countries, where space-heating requirements are marginal. In these countries the solar heat is used for preparing water for washing or cleaning purposes, and this process works in one, or — maximum — a few daily cycles. In countries located at higher latitudes, where space heating is necessary in cold months, the current solar energy is insufficient to meet the space heating demand. The heat storage in deep layer of the ground is the one of possible way for solution of this problem. During the heating season, energy storage is discharged supplying the heat pomp cooperating with domestic heating system and during the summer months the storage can be charged by fluid heated in solar collectors. The main aim of presented research was analysis of using the ground layer as a heat storage system in the countries located in higher latitudes. The first variable taken into consideration was the output temperature of water leaving the solar collectors. The temperature distribution in the ground depends on the inlet water temperature, primary heated in the solar collectors, and forced into vertical boreholes. The temperature field in the ground was calculated using the duFort-Frankel finite-difference numerical method. A numerical code for 3D time dependent storage simulation has been created. The next step of analysis was calculation of waters’ temperature at the borehole output during cold months when the ground storage is discharged. This water works as a low-temperature reservoir of the heat pomp supplying the dwelling heating system. The solution of the problem is focused on an optimization of all parameters for the most efficient utilization of energy stored in the ground. The numerical genetic algorithms are scheduled to use to achieve this target.

Review of Thermal Performance and Efficiency in Evacuated Tube Solar Collector with Various Nanofluids

2017 ◽  
Vol 25 (02) ◽  
pp. 1730001 ◽  
Author(s):  
Hyeongmin Kim ◽  
Jinhyun Kim ◽  
Honghyun Cho
Keyword(s):  
Heat Transfer ◽  
New Technology ◽  
Heating System ◽  
Experimental Methods ◽  
Solar Collectors ◽  
Parabolic Trough ◽  
Solar Absorption ◽  
Evacuated Tube Solar Collector ◽  
Evacuated Tube ◽  
Technology Area

With the development of nanotechnology, building a new technology area in a variety of fields and achieving the best performance has become possible. Several studies on the performance of a solar heating system have been conducted using various nanofluids because the efficiency of heat transfer of nanofluids is high. Various previous studies, including theoretical, numerical, and experimental methods, were conducted using nanofluids for flat-plate, evacuated tube, direct solar absorption, parabolic trough, and heat pipe solar collectors. The present work provides an overview of the recent research on the performance of evacuated tube solar collectors using various nanofluids. The experimental and numerical results reported by several researchers, such as the thermal conductivity, heat capacity, and heat transfer coefficient of nanofluids, are first reported. The studies on the evacuated tube solar collectors with nanofluids were then investigated and summarized.

scholarly journals Thermo-Economic Comparisons of Environmentally Friendly Solar Assisted Absorption Air Conditioning Systems

2021 ◽  
Vol 11 (5) ◽  
pp. 2442
Author(s):  
Adil Al-Falahi ◽  
Falah Alobaid ◽  
Bernd Epple
Keyword(s):  
Cooling System ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Absorption Refrigeration ◽  
Parabolic Trough ◽  
Solar Absorption ◽  
Evacuated Tube Collectors ◽  
Solar Absorption Cooling ◽  
Solar Field

Absorption refrigeration cycle is considered a vital option for thermal cooling processes. Designing new systems is needed to meet the increasing communities’ demands of space cooling. This should be given more attention especially with the increasing conventional fossil fuel energy costs and CO2 emission. This work presents the thermo-economic analysis to compare between different solar absorption cooling system configurations. The proposed system combines a solar field, flashing tank and absorption chiller: two types of absorption cycle H2O-LiBr and NH3-H2O have been compared to each other by parabolic trough collectors and evacuated tube collectors under the same operating conditions. A case study of 200 TR total cooling load is also presented. Results reveal that parabolic trough collector combined with H2O-LiBr (PTC/H2O-LiBr) gives lower design aspects and minimum rates of hourly costs (5.2 $/h) followed by ETC/H2O-LiBr configuration (5.6 $/h). H2O-LiBr gives lower thermo-economic product cost (0.14 $/GJ) compared to the NH3-H2O (0.16 $/GJ). The absorption refrigeration cycle coefficient of performance ranged between 0.5 and 0.9.

scholarly journals Thermodynamic Performance of a Double-Effect Absorption Refrigeration Cycle Based on a Ternary Working Pair: Lithium Bromide + Ionic Liquids + Water

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4200 ◽  
Author(s):  
Yiqun Li ◽  
Na Li ◽  
Chunhuan Luo ◽  
Qingquan Su
Keyword(s):  
Least Squares Method ◽  
Operating Temperature ◽  
Double Effect ◽  
Coefficient Of Performance ◽  
Specific Enthalpy ◽  
Refrigeration Cycle ◽  
Absorption Refrigeration ◽  
Temperature Range ◽  
Thermodynamic Performance ◽  
Operating Temperature Range

For an absorption cycle, a ternary working pair LiBr–[BMIM]Cl(2.5:1)/H2O was proposed as a new working pair to replace LiBr/H2O. The thermodynamic properties including specific heat capacity, specific enthalpy, density, and viscosity were systematically measured and fitted by the least-squares method. The thermodynamic performance of a double-effect absorption refrigeration cycle based on LiBr–[BMIM]Cl(2.5:1)/H2O was investigated under different refrigeration temperatures from 5 °C to 12 °C. Results showed that the ternary working pair LiBr–[BMIM]Cl(2.5:1)/H2O had advantages in the operating temperature range and corrosivity. Compared with LiBr/H2O, the operating temperature range was 20 °C larger, and the corrosion rates of carbon steel and copper were reduced by more than 50% at 453.15 K. However, the double-effect absorption refrigeration cycle with LiBr–[BMIM]Cl(2.5:1)/H2O achieved a coefficient of performance (COPc) from 1.09 to 1.46 and an exergetic coefficient of performance (ECOPc) from 0.244 to 0.238, which were smaller than those based on LiBr/H2O due to the higher generation temperature and larger flow ratio.

Effect of Operating Temperature on the Performance and Thermal Load of Water/Lithium Bromide Vapour Absorption Heat Pump in the Absence of Solution Heat Exchanger

2014 ◽  
Vol 592-594 ◽  
pp. 1510-1514
Author(s):  
S. Manu ◽  
T.K. Chandrashekar ◽  
A.J. Antony
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Thermal Load ◽  
Operating Temperature ◽  
Lithium Bromide ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Absorption Refrigeration ◽  
Efficiency Ratio ◽  
Absorption Heat Pump

In this investigation, a thorough thermodynamic analysis of the water/lithium bromide absorption refrigeration cycle in the absence of solution heat exchanger is performed. The influence of operating temperature on the thermal loads of components, COPc (Carnot Coefficient of Performance), COPE (Enthalpy based Coefficient of Performance) and efficiency ratio (η) is studied. It is concluded that the COPc and COPE values decreases with increasing condenser and absorber temperature but increase with increasing generator and evaporator temperatures .

Study of a Solar Absorption Refrigeration Machine in the Moroccan Climate

2019 ◽  
Vol 13 ◽  
pp. 1197-1204 ◽  
Author(s):  
J. Dardouch ◽  
M. Charia ◽  
A. Bernatchou ◽  
A. Dardouch ◽  
S. Malaine ◽  
...  
Keyword(s):  
Absorption Refrigeration ◽  
Solar Absorption ◽  
Refrigeration Machine

scholarly journals Numerical Modeling and Performance Evaluation of Standing Wave Thermoacoustic Refrigerators with a Multi-Layered Stack

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4360
Author(s):  
Umar Nawaz Bhatti ◽  
Salem Bashmal ◽  
Sikandar Khan ◽  
Rached Ben-Mansour
Keyword(s):  
Standing Wave ◽  
Numerical Study ◽  
Temperature Drop ◽  
Acoustic Power ◽  
Heat Energy ◽  
Coefficient Of Performance ◽  
Material Layer ◽  
And Performance ◽  
Stacked Material ◽  
Thermoacoustic Refrigerators

Thermoacoustic refrigerators have huge potential to replace conventional refrigeration systems as an alternative clean refrigeration technology. These devices utilize conversion of acoustic power and heat energy to generate the desired cooling. The stack plays a pivotal role in the performance of Standing Wave Thermoacoustic Refrigerators (SWTARs), as the heat transfer takes place across it. Performance of stacks can be significantly improved by making an arrangement of different materials inside the stack, resulting in anisotropic thermal properties along the length. In the present numerical study, the effect of multi-layered stack on the refrigeration performance of a SWTAR has been evaluated in terms of temperature drop across the stack, acoustic power consumed and device Coefficient of Performance (COP). Two different aspects of multi-layered stack, namely, different material combinations and different lengths of stacked layers, have been investigated. The combinations of four stack materials and length ratios have been investigated. The numerical results showed that multi-layered stacks produce lower refrigeration temperatures, consume less energy and have higher COP value than their homogeneous counterparts. Among all the material combinations of multi-layered stack investigated, stacks composed of a material layer with low thermal conductivity at the ends, i.e., RVC, produced the best performance with an increase of 26.14% in temperature drop value, reduction in the acoustic power consumption by 4.55% and COP enhancement of 5.12%. The results also showed that, for a constant overall length, an increase in length of side stacked material layer results in an increase in values of both temperature drop and COP.

Performance Evaluation of a Solar Water Heating System for Industrial Application

2012 ◽  
Vol 512-515 ◽  
pp. 130-136
Author(s):  
Keh Chin Chang ◽  
Wei Min Lin ◽  
Yi Mei Liu ◽  
Tsong Sheng Lee ◽  
Kung Ming Chung
Keyword(s):  
Performance Evaluation ◽  
Heating System ◽  
Economic Viability ◽  
Solar Collectors ◽  
Water Heating ◽  
Policy Makers ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Water Heating System

The total area of solar collectors installed in Taiwan had exceeded 2 million square meters by the end of 2010. However, there were only 98 systems in operation with area of solar collectors installed exceeding 100 square meters from 2001 to 2010. To increase industrial awareness of solar water heating technologies, a nursery greenhouse was chosen as the case study to evaluate its thermal performance throughout the months of May 2010 to April 2011. The results showed that the solar energy collected and heat loss during the night hours would affect the thermal efficiency, economic viability and attractiveness of a SWH. This study would provide useful information for all parties related to this market, manufacturers, potential users and policy-makers.

Sign in / Sign up

Export Citation Format

Share Document