scholarly journals Progressive Development and Challenges Faced by Solar Rotary Desiccant-Based Air-Conditioning Systems: A Review

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1785
Author(s):  
Ranjan Pratap Singh ◽  
Ranadip K. Das
Keyword(s):  
Solar Energy ◽  
Air Conditioning ◽  
Energy Use ◽  
Operating Cost ◽  
Electrical Energy ◽  
Low Grade ◽  
Vapor Compression ◽  
Cooling Systems ◽  
Ongoing Research ◽  
Air Conditioning Systems

A rotary desiccant-based air-conditioning system is a heat-driven hybrid system which combines different technologies such as desiccant dehumidification, evaporative cooling, refrigeration, and regeneration. This system has an opportunity to utilize low-grade thermal energy obtained from the sun or other sources. In this paper, the basic principles and recent research developments related to rotary desiccant-based cooling systems are recalled and their applications and importance are summarized. It is shown that with novel system configurations and new desiccant materials, there is great potential for improving the performance and consistency of rotary desiccant systems; at the same time, the use of solar energy for regeneration purposes can minimize the operating cost to a great extent. Some examples are presented to demonstrate how rotary desiccant air conditioning can be a promising solution for replacing traditional vapor-compression air-conditioning systems. Recent advances and ongoing research related to solar-powered hybrid rotary desiccant cooling systems are also summarized. The hybrid systems make use of a vapor-compression system in order to have better operational flexibility. These systems, although they consume electrical energy, use solar energy as the principal source of energy, and hence, significant savings of premium energy can be obtained compared to conventional vapor-compression systems. However, further research and development are required in order to realize the sustainable operation of solar rotary desiccant air-conditioning systems, as solar energy is not steady. Reductions in capital cost and size, along with improvements in efficiency and reliability of the system is still needed for it to become a player in the market of air conditioning.

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.

Open-Cycle Desiccant Air Conditioning as an Alternative to Vapor Compression Cooling in Residential Applications

1984 ◽  
Vol 106 (3) ◽  
pp. 252-260 ◽  
Author(s):  
J. J. Jurinak ◽  
J. W. Mitchell ◽  
W. A. Beckman
Keyword(s):  
Solar Energy ◽  
Air Conditioning ◽  
Energy Use ◽  
Energy System ◽  
Primary Energy ◽  
Vapor Compression ◽  
Air Conditioners ◽  
Open Cycle ◽  
Vapor Compression Cooling ◽  
Better Than

The performance of open-cycle desiccant air conditioners for residential applications is evaluated. The performance of these systems is compared to that of vapor compression air conditioners on the basis of primary energy use and cost. Systems with improved dehumidifiers can achieve seasonal COP’s on the order of 1.1. These systems, when coupled with a solar energy system to supply regeneration energy, are significantly better than conventional air conditioners on a primary energy basis, but are not presently cost-competitive.

Hybrid Liquid Desiccant/Vapour Compression Air-Conditioning Systems: A Critical Review

2008 ◽  
Author(s):  
Roza I. Christodoulaki ◽  
Emmanuil D. Rogdakis ◽  
Irene P. Koronaki
Keyword(s):  
Air Conditioning ◽  
Waste Heat ◽  
Electrical Energy ◽  
Hot Water ◽  
Vapor Compression ◽  
Solar Thermal Energy ◽  
Liquid Desiccant ◽  
Design Variables ◽  
Air Conditioning Systems ◽  
Vapour Compression

Hybrid Liquid Desiccant Cooling / Vapour Compression Systems is an environmentally friendly technology used to condition the internal environment of buildings. In contrast to conventional vapor compression air conditioning systems, in which the electrical energy drives the cooling cycle, desiccant cooling is heat driven; therefore, hybrid LDC/VCS have the potential to utilise cleaner energy sources such as gas, hot water, waste heat or solar thermal energy. In hybrid LDC/VCS, the latent cooling load is handled by the desiccant dehumidifier, while the sensible is handled by a conventional VCS. Hybrid systems combining liquid desiccant cooling with Vapor Compression Systems, Vapor Absorption Systems and Solar Collectors use less electrical energy compared to conventional air-conditioning alone, while these savings rise as the latent load increases. Unlike other surveys on desiccant cooling, this review focuses on a detailed coverage of the hybrid LDC/VC systems. Commonly used liquid desiccants are compared towards their physical properties. Hybrid LDC/VCS employing various components and features are summarized, while different system configurations are schematically presented. Key factors for the hybrid system performance are the desiccant material, the design variables and the conduction of experiments prior to operation.

scholarly journals Desiccant cooling as an alternative to traditional air conditioners in green cooling technology

2019 ◽  
pp. 01-13
Author(s):  
Jani DB
Keyword(s):  
Air Conditioning ◽  
Energy Savings ◽  
Cooling System ◽  
Green Building ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Low Grade ◽  
Vapor Compression ◽  
Cooling Technology ◽  
Air Conditioning Systems

Desiccant-based dehumidification and air conditioning systems are considered as an energy efficient alternative to traditional vapor compression based air-conditioning systems for green building cooling technology especially in tropical hot and humid ambient climates. It is a novel green cooling technology that makes use of low-grade heat for building air conditioning. It is seen that the desiccant based dehumidification and cooling can efficiently provide comfort conditions in subtropical and especially hot and humid tropical climates. The desiccant integrated novel cooling system has a significant higher coefficient of performance compared to the conventional vapor compression system resulting to substantial electrical energy savings during the summer season by use of renewable solar energy, which also resulted in to major reduction in CO2 emissions. Therefore, these results demonstrate that there is a good potential in desiccant-based dehumidification and cooling system for energy and carbon savings while carry out building air-conditioning. Through a literature review, the feasibility of the desiccant assisted air conditioning in hot and humid climatic conditions is proven and the advantages it can offer in terms energy and cost savings are underscored. Keywords: Air-conditioning; Desiccant cooling; Dehumidification; Green cooling; Thermal comfort

scholarly journals Performance Characteristics of Solid-Desiccant Evaporative Cooling Systems

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2574 ◽  
Author(s):  
Ramadas Narayanan ◽  
Edward Halawa ◽  
Sanjeev Jain
Keyword(s):  
Air Conditioning ◽  
Natural Ventilation ◽  
Waste Heat ◽  
Numerical Study ◽  
Evaporative Cooling ◽  
Peak Load ◽  
Dew Point ◽  
Low Grade ◽  
Subtropical Climate ◽  
Cooling Systems

Air conditioning accounts for up to 50% of energy use in buildings. Increased air-conditioning-system installations not only increase total energy consumption but also raise peak load demand. Desiccant evaporative cooling systems use low-grade thermal energy, such as solar energy and waste heat, instead of electricity to provide thermal comfort. This system can potentially lead to significant energy saving, reduction in carbon emissions, and it has a low dew-point operation and large capacity range. Their light weight, simplicity of design, and close-to-atmospheric operation make them easy to maintain. This paper evaluates the applicability of this technology to the climatic conditions of Brisbane, Queensland, Australia, specifically for the residential sector. Given the subtropical climate of Brisbane, where humidity levels are not excessively high during cooling periods, the numerical study shows that such a system can be a potential alternative to conventional compression-based air-conditioning systems. Nevertheless, the installation of such a system in Brisbane’s climate zone requires careful design, proper selection of components, and a cheap heat source for regeneration. The paper also discusses the economy-cycle options for this system in such a climate and compares its effectiveness to natural ventilation.

The study of solar absorption air-conditioning systems

2005 ◽  
Vol 16 (4) ◽  
pp. 59-66 ◽  
Author(s):  
V Mittal ◽  
KS Kasana ◽  
NS Thakur
Keyword(s):  
Air Conditioning ◽  
Lithium Bromide ◽  
Cooling Systems ◽  
Solar Absorption ◽  
Air Conditioning System ◽  
Heating And Cooling ◽  
Absorption Cooling ◽  
Solar Powered ◽  
Solar Absorption Cooling ◽  
Air Conditioning Systems

An air-conditioning system utilizing solar energy would generally be more efficient, cost wise, if it was used to provide both heating and cooling requirements in the building it serves. Various solar powered heating systems have been tested extensively, but solar powered air conditioning systems have received very little attention. Solar powered absorption cooling systems can serve both heating and cooling requirements in the building it serves. Many researchers have studied the solar absorption air conditioning system in order to make it economically and technically viable. But still, much more research in this area is needed. This paper will help many researchers working in this area and provide them with fundamental knowledge on absorption systems, and a detailed review on the past efforts in the field of solar absorption cooling systems with the absorption pair of lithium-bromide and water. This knowledge will help them to start the parametric study in order to investigate the influence of key parameters on the overall system performance.

Use of Solar Desiccant Air-Conditioning Systems in Commercial Buildings

Solar Energy ◽  
2005 ◽  
Author(s):  
Anthony Domenic Calderone ◽  
Mir-Akbar Hessami ◽  
Stefan Brey
Keyword(s):  
Air Conditioning ◽  
Greenhouse Gas Emission ◽  
Electrical Energy ◽  
Sole Source ◽  
Solar Thermal ◽  
Commercial Building ◽  
Solar Thermal Energy ◽  
Cooling Cycle ◽  
Solar Thermal Collectors ◽  
Air Conditioning Systems

Desiccant air conditioning systems provide an environmentally friendly alternative to the traditional methods of conditioning a building’s internal environment. Whilst conventional air conditioning systems rely on electrical energy to drive the cooling cycle, desiccant cooling is a heat driven cycle. As such, desiccant cooling provides an opportunity to be coupled with solar thermal collectors to reduce energy demands. This paper discusses the potential for a desiccant cooling cycle utilising solar thermal energy as the sole source of heat for regeneration of the desiccant. The study demonstrates that under the assumed design conditions this system will theoretically not require a regeneration heater. Installation of such a system in a commercial building would be extremely beneficial in reducing building’s energy consumption and therefore greenhouse gas emission.

Investigation on the Intake Process for a Theoretical Twin Opposite Piston Compressor Using R744 Refrigerant

2016 ◽  
Vol 823 ◽  
pp. 75-78
Author(s):  
Doru Groza ◽  
Dan Mihai Dogariu
Keyword(s):  
Air Conditioning ◽  
Piston Compressor ◽  
Environmental Issues ◽  
Point Of View ◽  
Vapor Compression ◽  
Household Appliances ◽  
Intake Process ◽  
Vapor Compression Refrigeration ◽  
Energetic Point ◽  
Air Conditioning Systems

This study aims to validate the use of R744 for a resonant twin piston compressor for domestic applications. The vapor-compression refrigeration is the most commonly approached method for cooling household appliances such as refrigerators and air conditioning systems. The R134a refrigerant is one of the most suitable refrigerants from an energetic point of view. R744 (CO2) compressors are less efficient, but the fact that the R134a raises serious environmental issues pushes commercial trend towards the usage of R744 [1]-[3]. Use of R744 in household appliances is currently an open topic and no company has switched yet to the environmental-friendly alternative. In this paper the fill efficiency will be simulated in order to validate if a conventional compressor such as the opposite twin piston compressor is capable of filling with refrigerant when operating at a 50Hz frequency. Such a validation can enable further investigations regarding the replacement of R134a with R744.

Design for Sustainable Data Center Energy Use and Eco-Footprint

2010 ◽  
Author(s):  
Milton Meckler
Keyword(s):  
Data Center ◽  
Air Conditioning ◽  
Fossil Fuels ◽  
Energy Use ◽  
Data Centers ◽  
Ghg Emissions ◽  
High Energy ◽  
Operational Reliability ◽  
Energy Utilization ◽  
Air Conditioning Systems

What does remain a growing concern for many users of Data Centers is their continuing availability following the explosive growth of internet services in recent years, The recent maximizing of Data Center IT virtualization investments has resulted in improving the consolidation of prior (under utilized) server and cabling resources resulting in higher overall facility utilization and IT capacity. It has also resulted in excessive levels of equipment heat release, e.g. high energy (i.e. blade type) servers and telecommunication equipment, that challenge central and distributed air conditioning systems delivering air via raised floor or overhead to rack mounted servers arranged in alternate facing cold and hot isles (in some cases reaching 30 kW/rack or 300 W/ft2) and returning via end of isle or separated room CRAC units, which are often found to fight each other, contributing to excessive energy use. Under those circumstances, hybrid, indirect liquid cooling facilities are often required to augment above referenced air conditioning systems in order to prevent overheating and degradation of mission critical IT equipment to maintain rack mounted subject rack mounted server equipment to continue to operate available within ASHRAE TC 9.9 prescribed task psychometric limits and IT manufacturers specifications, beyond which their operational reliability cannot be assured. Recent interest in new web-based software and secure cloud computing is expected to further accelerate the growth of Data Centers which according to a recent study, the estimated number of U.S. Data Centers in 2006 consumed approximately 61 billion kWh of electricity. Computer servers and supporting power infrastructure for the Internet are estimated to represent 1.5% of all electricity generated which along with aggregated IT and communications, including PC’s in current use have also been estimated to emit 2% of global carbon emissions. Therefore the projected eco-footprint of Data Centers into the future has now become a matter of growing concern. Accordingly our paper will focus on how best to improve the energy utilization of fossil fuels that are used to power Data Centers, the energy efficiency of related auxiliary cooling and power infrastructures, so as to reduce their eco-footprint and GHG emissions to sustainable levels as soon as possible. To this end, we plan to demonstrate significant comparative savings in annual energy use and reduction in associated annual GHG emissions by employing a on-site cogeneration system (in lieu of current reliance on remote electric power generation systems), introducing use of energy efficient outside air (OSA) desiccant assisted pre-conditioners to maintain either Class1, Class 2 and NEBS indoor air dew-points, as needed, when operated with modified existing (sensible only cooling and distributed air conditioning and chiller systems) thereby eliminating need for CRAC integral unit humidity controls while achieving a estimated 60 to 80% (virtualized) reduction in the number servers within a existing (hypothetical post-consolidation) 3.5 MW demand Data Center located in southeastern (and/or southern) U.S., coastal Puerto Rico, or Brazil characterized by three (3) representative microclimates ranging from moderate to high seasonal outside air (OSA) coincident design humidity and temperature.

scholarly journals Possibilities of using solar energy in the processes of cooling external zones of people

2018 ◽  
Vol 49 ◽  
pp. 00016
Author(s):  
Ewelina Dec ◽  
Robert Sekret ◽  
Bożena Babiarz
Keyword(s):  
Solar Energy ◽  
Radiation Energy ◽  
Air Cooling ◽  
Cooling Systems ◽  
Maximum Daily Temperature ◽  
Air Temperatures ◽  
Technical Potential ◽  
Hot Days ◽  
Hot Weather ◽  
Air Conditioning Systems

Meteorological analyzes unambiguously indicate climate warming. An increase in average air temperatures is recorded in both winter and summer. In recent years, an increasing number of hot and very hot days are observed, and the duration of series of days with maximum daily temperature above 30°C is also longer. Occurrence of hot weather adversely affects the person staying outside. The ever-increasing requirements related to thermal comfort, enforce the provision of appropriate conditions not only in the rooms, but also in the external zones of people. Cooling the air in outdoor zones using standard air-conditioning systems can be expensive due to the high demand for electricity. Ensuring cooling through the use of renewable energy, such as solar energy, is a key solution to energy and environmental problems. In this article, the technical potential of solar radiation energy was determined based on data from the Rzeszow- Jasionka meteorological station and the possibilities of using solar energy in air cooling systems in external zones were presented.

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