An Analytical Examination of Methods for Improving the Performance of Desiccant Cooling Systems

1991 ◽  
Vol 113 (3) ◽  
pp. 157-163 ◽  
Author(s):  
R. K. Collier ◽  
B. M. Cohen
Keyword(s):  
Heat Capacity ◽  
Solar Collector ◽  
Air Conditioning ◽  
Cooling System ◽  
Coefficient Of Performance ◽  
Cooling Systems ◽  
Transfer Processes ◽  
Air Stream ◽  
Wave Nature ◽  
Mass Transfer Processes

The conventional Pennington Cycle desiccant cooling system offers a clear opportunity for heat-actuated air conditioning. However, efforts to translate this opportunity into commercially viable hardware have not been successful. The performance of the hardware has been inadequate, resulting in excessive solar collector requirements or, in the case of gas-fired equipment, uneconomical use of natural gas. Two methods for improving the coefficient of performance (COP) of these systems are: (1) the addition of inert heat capacity to the desiccant matrix, and (2) “staging” the regeneration air stream. An analysis is presented in this paper which explains the benefits and drawbacks of these methods based upon the wave nature of the heat and mass transfer processes occurring within the desiccant bed. The results indicate that the best overall system performance is obtained by staging the regeneration process while minimizing the amount of inert heat capacity.

scholarly journals System Design of Solar Absorption Cooling : A Case Study in Building of Engineering Physics Department UGM

KnE Energy ◽  
2015 ◽  
Vol 2 (2) ◽  
pp. 22
Author(s):  
Andang Widiharto ◽  
Didit Setyo Pamuji ◽  
Atik Nurul Laila ◽  
Fiki Rahmatika Salis ◽  
Luthfi Zharif ◽  
...  
Keyword(s):  
Global Warming ◽  
Solar Collector ◽  
Air Conditioning ◽  
Cooling System ◽  
Renewable Energy Sources ◽  
Coefficient Of Performance ◽  
Thermal Coefficient ◽  
Solar Absorption ◽  
Absorption Cooling ◽  
Solar Absorption Cooling

<p>Air conditioning (AC) is one of the most building’s energy consumer, included in building of Engineering Physisc’s Departement, Universitas Gadjah Mada (UGM). The declining of fossil fuel reserves and the increasing effects of global warming, forcing the world to switch to renewable energy sources. This paper discusses the design of solar absorption cooling system to replace conventional AC in seven lecture halls of Engineering Physic’s Departement, UGM. There are some steps that have been done to design the solar absorption cooling, i.e. do a study of the potential availability of solar energy, calculate the cooling loads, analyze the thermodynamic process of the system, determine the type of collector to be used and calculate area of solar collector needed. The thermal coefficient of performance (COP) of the system designed was about 0.84 which could use some types of flat plate solar collector with each area corresponding to each efficiency values. </p><p><strong>Keyword</strong> : Air conditioning; global warming; solar absorption cooling; solar collector</p>

Mass Nature of Heat and Its Application VII: Coupled Heat and Mass Transfer Optimization Based on the Entransy Theory

2010 ◽  
Author(s):  
Qun Chen ◽  
Moran Wang ◽  
Ning Pan ◽  
Zeng-Yuan Guo
Keyword(s):  
Mass Transfer ◽  
Thermal Resistance ◽  
Heat And Mass Transfer ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Entransy Dissipation ◽  
Cooling Systems ◽  
Entransy Theory ◽  
Transfer Processes ◽  
Mass Transfer Processes

Using the analogy between heat and mass transfer processes, the recently developed entransy theory is extended in this paper to tackle the coupled heat and mass transfer processes so as to analyze and optimize the performance of evaporative cooling systems. We first introduce a few new concepts including the moisture entransy, moisture entransy dissipation, and the thermal resistance in terms of the moisture entransy dissipation. Thereinafter, the moisture entransy is employed to describe the endothermic ability of a moist air. The moisture entransy dissipation on the other hand is used to measure the loss of the endothermic ability, i.e. the irreversibility, in the coupled heat and mass transfer processes, which consists of three parts: (1) the sensible heat entransy dissipation, (2) the latent heat entransy dissipation, and (3) the entransy dissipation induced by a temperature potential. And then the new thermal resistance, defined as the moisture entransy dissipation rate divided by the squared refrigerating effect output rate, is recommended as an index to effectively reflect the performance of the evaporative cooling system. Meanwhile, a minimum thermal resistance law for optimizing the evaporative cooling systems is developed. In the end, several direct and indirect evaporative cooling processes are analyzed to illustrate the applications of the proposed concepts.

scholarly journals A New Design of an Integrated Solar Absorption Cooling System Driven by an Evacuated Tube Collector: A Case Study for Baghdad, Iraq

2020 ◽  
Vol 10 (10) ◽  
pp. 3622 ◽  
Author(s):  
Adil Al-Falahi ◽  
Falah Alobaid ◽  
Bernd Epple
Keyword(s):  
Thermal Performance ◽  
Air Conditioning ◽  
Cooling System ◽  
Electrical Power ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Solar Absorption ◽  
Air Conditioning System ◽  
Solar Fraction ◽  
Design Variables

The electrical power consumption of refrigeration equipment leads to a significant influence on the supply network, especially on the hottest days during the cooling season (and this is besides the conventional electricity problem in Iraq). The aim of this work is to investigate the energy performance of a solar-driven air-conditioning system utilizing absorption technology under climate in Baghdad, Iraq. The solar fraction and the thermal performance of the solar air-conditioning system were analyzed for various months in the cooling season. It was found that the system operating in August shows the best monthly average solar fraction (of 59.4%) and coefficient of performance (COP) (of 0.52) due to the high solar potential in this month. Moreover, the seasonal integrated collector efficiency was 54%, providing a seasonal solar fraction of 58%, and the COP of the absorption chiller was 0.44, which was in limit, as reported in the literature for similar systems. A detailed parametric analysis was carried out to evaluate the thermal performance of the system and analyses, and the effect of design variables on the solar fraction of the system during the cooling season.

scholarly journals Design of an adiabatic air conditioning package system

2022 ◽  
Vol 13 ◽  
pp. 8
Author(s):  
Sachin Sunil Mothiravally ◽  
Sachidananda Hassan Krishanmurthy
Keyword(s):  
Thermal Analysis ◽  
Energy Consumption ◽  
Return On Investment ◽  
Air Conditioning ◽  
Energy Savings ◽  
Coefficient Of Performance ◽  
Cooling Systems ◽  
Air Conditioning System ◽  
Adiabatic Cooling ◽  
Save Energy

Air conditioning plays a significant role to maintain a cool atmosphere in warm conditions, However, the power consumed by the machine is higher. The commercial prevailing cooling systems are required to operate ventilation and cooling systems in buildings and in turn consumes more power. These systems apart from consuming electricity it also adds to the CO2 emissions to our environment. These energy consumption and CO2 emissions can be decreased by the assistance of energy effective frameworks to the prevailing air conditioning system. The study was conducted on a package unit of 414.2 kW by measuring the relative humidity, dry bulb, and wet bulb temperature to investigate the effect of indirect evaporative cooling on the systems COP. Also, the modelling of the package unit was done using Creo software and the analysis was carried out using ANSYS considering the flow and thermal analysis for different components of the package units. From this analysis it can be observed that by implementing the adiabatic cooling in package unit it is possible to save energy consumption. From the results it can be concluded that energy efficiency was more and the return on investment is high. Also, coefficient of performance of this machine is high and consumes less electricity and the expected energy savings is 20%.

scholarly journals Optimization of heat and mass transfer processes in air conditioning systems in public buildings

2020 ◽  
Vol 4 (4) ◽  
pp. 49-56
Author(s):  
A. V. Tsygankov ◽  
◽  
V. I. Lysev ◽  
A. K. Rubtsov ◽  
A. S. Shilin ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Experimental Study ◽  
Air Conditioning ◽  
Heat Fluxes ◽  
Public Buildings ◽  
Transfer Processes ◽  
Air Temperatures ◽  
Mass Transfer Processes ◽  
Predicted Values ◽  
Air Conditioning Systems

Increasing the energy efficiency of air conditioning systems in public buildings and structures is an actual task. A mathematical model is proposed for determining the values of internal air temperatures and temperatures of the surfaces of enclosure in order to calculate the predicted values of heat fluxes in buildings and structures. An experimental study has been carried out showing the relevance of the proposed method

scholarly journals KINERJA KOLEKTOR TIPE PLAT DATAR PADA MESIN PENDINGIN ADSORPSI TENAGA SURYA DI KOTA MEDAN

2018 ◽  
Vol 7 (2) ◽  
pp. 94
Author(s):  
Tulus Burhanuddin Sitorus
Keyword(s):  
Solar Collector ◽  
Statistical Study ◽  
Cooling System ◽  
Weather Conditions ◽  
Coefficient Of Performance ◽  
Total Solar Radiation ◽  
Collector Efficiency ◽  
Powder Activated Carbon ◽  
Adsorption Cooling System ◽  
Flat Plate Collector

The performance of a flat plate collector on adsorption refrigerator driven by the solar collector was investigated in the present work. Based on a study conducted no researcher studies the performance of solar collectors used in adsorption cooling system. The adsorbent used in the collector was 20 kg ordinary powder activated carbon of coconut shell produced in the Sumatera Utara province of Indonesia, 5 liters of methanol as adsorbate and 6 liters of water as the medium that was cooled. The experiments were carried out under varying weather conditions with total solar radiation about 12619-17807 kJ/m2/cycle in Medan city. The experimental results show that the values of collector efficiency obtained were about 52.11-53.92%. The values of coefficient of performance (COP) obtained were in the range of 0.0318-0.0449. The results of the statistical study suggest that the effect of the weather conditions on collector efficiency thereabout 96%.

Performance Enhancement of Solar Air Conditioners Using Hybrid Heat Rejection System

2019 ◽  
Author(s):  
Abdul Ahad Iqbal ◽  
Ali Al-Alili
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Vapor Compression ◽  
Summer Period ◽  
Cooling Systems ◽  
Hybrid Cooling ◽  
Vapor Compression Cooling ◽  
Air Conditioning Systems ◽  
Sorption Systems ◽  
Dry Cooling

Abstract The performance of air conditioning systems is highly dependent on the environmental conditions of the high pressure side, where heat is rejected to the environment. Air conditioning systems utilize dry cooling systems which often don’t provide adequate cooling during peak cooling periods, or wet cooling systems which consume a lot of water. In this study, a novel hybrid cooling system that can provide both wet and dry cooling was modelled in TRNSYS, and used to provide cooling to closed sorption air conditioning systems. The performance of these systems with the hybrid cooling system was compared to the performance of a standard vapor compression cooling system being cooled by a dry cooling system. The COPsol of the vapor compression cooling system exhibited a decrease of almost 26% during the summer period, whereas the COPsol of the sorption systems increased by around 30%. Similarly, the cooling capacity of the vapor compression cooling system dropped by almost 5%, and for the sorption systems, it increased by around 20% during the summer period.

COMPUTER SIMULATION OF TRANSFER PROCESSES IN MICROJET BURNER DEVICES WITH SPECIAL COOLING SYSTEMS

2017 ◽  
Author(s):  
Nataliia Fialko ◽  
Viktor Prokopov ◽  
Sergiy Alioshko ◽  
Julii Sherenkovskiy ◽  
Nataliia Meranova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Computer Simulation ◽  
Cooling System ◽  
Cooling Systems ◽  
Transfer Processes ◽  
Flow And Heat Transfer ◽  
Inner Surface ◽  
Air Blowing

The analysis of efficiency of cooling system of the microjet stabilization burner devices is performed. The features of the flow and heat transfer in cooling systems with air blowing of the inner surface of flame stabilizator and with flat and circular impact jets are studied.

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