Solar Assisted Desiccant Cooling Simulation for Different Climate Zones

2011 ◽  
Author(s):  
Wendell Concina ◽  
Suresh Sadineni ◽  
Robert Boehm
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Evaporative Cooling ◽  
The United States ◽  
Economic Benefits ◽  
Climatic Conditions ◽  
Hot Water ◽  
Low Grade ◽  
Cooling Systems ◽  
Climate Zones

Evaporative cooling is among the most cost effective methods of air conditioning, but is less efficient in humid climates. An evaporative system coupled with a desiccant wheel can operate effectively in broader climatic conditions. These cooling systems can substitute traditional vapor compression air conditioning systems as they involve environmentally friendly cooling processes with reduced electricity demand (which is commonly generated from fossil fuels) along with no harmful CFC based refrigerant usage. Furthermore, direct utilization of low grade energy sources such as solar thermal energy or flue gas heat can drive the desiccant regeneration process, thus providing economic benefits. This study presents the results of simulations of desiccant cooling system performance for different climate zones of the United States. Solar assisted desiccant air conditioning is particularly useful where there are abundant solar resources with high temperature and humidity levels. Building energy simulations determined cooling energy requirements for the building. Simulation of an evacuated solar hot water collector model provided the heat energy available for regeneration of the desiccant. Solid desiccant of common material such as silica gel used in a rotary wheel is simulated using established validated computer models; this is coupled with evaporative cooling. Transients of the overall system for different cooling loads and solar radiation levels are presented. Finally, feasibility studies of the desiccant cooling systems are presented in comparison with traditional cooling system. Further analysis of the data presents optimization opportunities. Energy savings were achieved in all climatic conditions with decreased effectiveness in more humid conditions.

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.

Development of an Improved Desiccant-Based Evaporative Cooling System for Gas Turbines

2008 ◽  
Author(s):  
Amir Abbas Zadpoor ◽  
Ali Asadi Nikooyan
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Climatic Conditions ◽  
Cooling Systems ◽  
Actual Performance ◽  
Evaporative Cooling System ◽  
Industrial Gas Turbine ◽  
Gas Turbine Cycle

The evaporative inlet cooling systems used for inlet cooling of gas turbines during hot summers do not work well in humid areas. However, desiccant wheels can be used to dehumidify the air before passing it trough the evaporative cooler. Since the desiccant wheels work adiabatically, the resulting air is hotter than the air introduced to the wheel and an evaporative cooling system is used to cool down the dehumidified air. Combined direct and indirect evaporative coolers have been already used to investigate the effects of dehumidification on the effectiveness of the evaporation cooling systems. It is shown that a single desiccant wheel does not offer much higher effectiveness compared to the multiple-stage evaporative systems. In this paper, an improved version of the desiccant inlet cooling system is presented. Additional dehumidification and indirect evaporative cooling stages are added to increase the effectiveness of the inlet cooling. A typical gas turbine cycle along with an industrial gas turbine with actual performance curves are used to simulate the thermal cycle in presence of the different inlet cooling systems. The simulations are carried out for three different climatic conditions. The improved and original desiccant-based systems are compared and it is shown that the added stages substantially improve the effectiveness of the desiccant-based inlet cooling.

scholarly journals Energy - Saving Potential of Evaporative Cooling System for Building Application - A Review

2020 ◽  
pp. 14-17
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Cooling Systems ◽  
Energy Saving Potential ◽  
The Earth ◽  
Direct Evaporative Cooling ◽  
Evaporative Cooling System ◽  
Air Conditioning Systems ◽  
Vapour Compression

The function of air conditioning systems has seen impressive development over the most recent couple of decades everywhere throughout the world, particularly in commercial buildings in ensuring the occupant thermal comfort. All the same, it is followed to have bad effects on the earth as well as increased power consumption in buildings. Hence, there has been extensive research to recognize options, in contrast to conventional vapour compression air conditioning systems. This account intends to review the ongoing improvements concerning evaporative cooling advancements that might give adequate cooling comfort, reduce environmental impact and lower energy consumption in buildings. Researches have done as on date in evaporative cooling systems centre predominantly around mainly on drawing down the dry bulb temperature of the incoming air. The theoretical efficiency of 100% can be achieved when the room dry bulb temperature is equal to the wet-bulb temperature of the outside atmospheric air. A wide literature review has been carried out and mapped out the best evaporative cooling systems. The review covers direct evaporative cooling, indirect evaporative cooling, and combined direct-indirect cooling systems.

scholarly journals Alternative Air-Conditioning Options for Developing Countries

2017 ◽  
Vol 2 (1) ◽  
pp. 76 ◽  
Author(s):  
Muhammad Kashif ◽  
Muhammad Sultan ◽  
Zahid Mahmood Khan
Keyword(s):  
Developing Countries ◽  
Air Conditioning ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Ambient Air ◽  
Climatic Conditions ◽  
Individual Characteristics ◽  
Coefficient Of Performance ◽  
Air Conditioning System ◽  
Evaporative Cooling System

This study assesses the potential selection of efficient air-conditioning (AC) and cooling systems in order to avoid excess power consumption, mitigation of harmful refrigerants generated by the existing AC systems. Several varieties of active and passive air-conditioning systems i.e. heating ventilating air-conditioning (HVAC), vapor compression air-conditioning (VCAC) conventional direct evaporative cooling (DEC) and indirect evaporative cooling (IEC)  and desiccant air-conditioning (DAC) systems are under practice for the cooling and dehumidification. The storage of agricultural products mainly based on product individual characteristics i.e. respiration rate, transpiration rate and moisture content of that product. Variant ambient air conditions and the type of application are the main parameters for the choice of air-conditioning system to get optimum performance. The DAC system subsidize the coefficient of performance (COP) in humid regions, coastal ranges of developing countries e.g. Karachi and Gawadar (Pakistan) with hot humid climatic conditions. In similar way, hottest regions of the country such as Sibbi, Jacobabad and Multan perform better results when incorporates with M-cycle evaporative cooling system. Variation in ambient air conditions directly affect the cooling load and the choice of sustainable air-conditioning system

scholarly journals Thermodynamic Performance Investigation of a Small-Scale Solar Compression-Assisted Multi-Ejector Indoor Air Conditioning System for Hot Climate Conditions

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4325
Author(s):  
Valerie Eveloy ◽  
Yusra Alkendi
Keyword(s):  
Air Conditioning ◽  
Power Plants ◽  
Cooling System ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Small Scale ◽  
Low Grade ◽  
Air Conditioner ◽  
Solar Thermal Energy ◽  
Ejector System

In year-round hot climatic conditions, conventional air conditioning systems consume significant amounts of electricity primarily generated by conventional power plants. A compression-assisted, multi-ejector space cooling system driven by low-grade solar thermal energy is investigated in terms of energy and exergy performance, using a real gas property-based ejector model for a 36 kW-scale air conditioning application, exposed to annually high outdoor temperatures (i.e., up to 42 °C), for four working fluids (R11, R141b, R245fa, R600a). Using R245fa, the multi-ejector system effectively triples the operating condenser temperature range of a single ejector system to cover the range of annual outdoor conditions, while compression boosting reduces the generator heat input requirement and improves the overall refrigeration coefficient of performance (COP) by factors of ~3–8 at medium- to high-bound condenser temperatures, relative to simple ejector cycles. The system solar fraction varies from ~0.2 to 0.9 in summer and winter, respectively, with annual average mechanical and overall COPs of 24.5 and 0.21, respectively. Exergy destruction primarily takes place in the ejector assembly, but ejector exergy efficiency improves with compression boosting. The system could reduce annual electric cooling loads by over 40% compared with a conventional local split air conditioner, with corresponding savings in electricity expenditure and GHG emissions.

scholarly journals Investigação experimental em escala reduzida sobre o uso de telhas cerâmicas como sistema de resfriamento evaporativo

2019 ◽  
Vol 1 (46) ◽  
pp. 121
Author(s):  
Marcelo Paes De Barros
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Temperature Drop ◽  
Porous Ceramics ◽  
Climatic Conditions ◽  
Evaporative Cooling System ◽  
Cooling Effects ◽  
Scale Experiment ◽  
Reduced Scale

<p>The present paper describes an experiment that clarifies the cooling effects of the constructed system. Tested in the Cuiabá, MT, environment, the system’s performance,, which works on the evaporative cooling principle made for this study using clay roof tiles was checked in terms of temperature drop and humidity rise air which passes through the system to the surroundings. The result showed that the cooling effect reached a maximum of 3.5 °C and increased the relative humidity of incoming air around 10%. The reduced-scale experiment has reached the appropriate temperature and humidity for air conditioning under human environmental comfort conditions in hot and dry climatic conditions, in 86.4% of the measurement periods. The use of porous ceramics as an evaporative cooling system offers the advantage of the integration into building elements.</p>

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

Research Progress of Liquid Desiccant Evaporative Cooling Air Conditioning System

2013 ◽  
Vol 732-733 ◽  
pp. 531-536
Author(s):  
Tong Hua Zou ◽  
Min Wang ◽  
Sai Feng Deng ◽  
Yong Li
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Research Progress ◽  
Low Grade ◽  
Liquid Desiccant ◽  
Air Conditioning System ◽  
Evaporative Cooling System ◽  
Cooling Technology ◽  
Cooling Air

Evaporative cooling technology is a refrigeration technology by water evaporating endothermic, with zero-pollution, environmental-friendly, energy saving, and other advantages, which makes it widely used. Nevertheless, due to its working characteristic, the application of evaporative cooling technology is limited, particularly in some areas with high humidity. Using the liquid desiccant dehumidification and evaporative cooling technology leads to a solution, named liquid desiccant evaporative cooling air conditioning system extends the application of evaporative cooling technology. This article on liquid desiccant evaporative cooling system provides a brief overview about research status, full usage of the low grade thermal energy, the practical application and new development of the system.

scholarly journals Evaporative Cooling Options for Building Air-Conditioning: A Comprehensive Study for Climatic Conditions of Multan (Pakistan)

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3061 ◽  
Author(s):  
Shazia Noor ◽  
Hadeed Ashraf ◽  
Muhammad Sultan ◽  
Zahid Mahmood Khan
Keyword(s):  
Thermal Comfort ◽  
Co2 Emissions ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Maximum Temperature ◽  
Human Thermal Comfort ◽  
Work Input ◽  
System Configurations

This study provides comprehensive details of evaporative cooling options for building air-conditioning (AC) in Multan (Pakistan). Standalone evaporative cooling and standalone vapor compression AC (VCAC) systems are commonly used in Pakistan. Therefore, seven AC system configurations comprising of direct evaporative cooling (DEC), indirect evaporative cooling (IEC), VCAC, and their possible combinations, are explored for the climatic conditions of Multan. The study aims to explore the optimum AC system configuration for the building AC from the viewpoints of cooling capacity, system performance, energy consumption, and CO2 emissions. A simulation model was designed in DesignBuilder and simulated using EnergyPlus in order to optimize the applicability of the proposed systems. The standalone VCAC and hybrid IEC-VCAC & IEC-DEC-VCAC system configurations could achieve the desired human thermal comfort. The standalone DEC resulted in a maximum COP of 4.5, whereas, it was 2.1 in case of the hybrid IEC-DEC-VCAC system. The hybrid IEC-DEC-VCAC system achieved maximum temperature gradient (21 °C) and relatively less CO2 emissions as compared to standalone VCAC. In addition, it provided maximum cooling capacity (184 kW for work input of 100 kW), which is 85% higher than the standalone DEC system. Furthermore, it achieved neutral to slightly cool human thermal comfort i.e., 0 to −1 predicted mean vote and 30% of predicted percentage dissatisfied. Thus, the study concludes the hybrid IEC-DEC-VCAC as an optimum configuration for building AC in Multan.

scholarly journals Experiments on Energy-Efficient Evaporative Cooling Systems for Poultry Farm Application in Multan (Pakistan)

2021 ◽  
Vol 13 (5) ◽  
pp. 2836
Author(s):  
Khawar Shahzad ◽  
Muhammad Sultan ◽  
Muhammad Bilal ◽  
Hadeed Ashraf ◽  
Muhammad Farooq ◽  
...  
Keyword(s):  
Heat Stress ◽  
Low Cost ◽  
Evaporative Cooling ◽  
Thermal Exposure ◽  
Climatic Conditions ◽  
The Body ◽  
Dew Point ◽  
Sweat Glands ◽  
Cooling Systems ◽  
Humidity Index

Poultry are one of the most vulnerable species of its kind once the temperature-humidity nexus is explored. This is so because the broilers lack sweat glands as compared to humans and undergo panting process to mitigate their latent heat (moisture produced in the body) in the air. As a result, moisture production inside poultry house needs to be maintained to avoid any serious health and welfare complications. Several strategies such as compressor-based air-conditioning systems have been implemented worldwide to attenuate the heat stress in poultry, but these are not economical. Therefore, this study focuses on the development of low-cost and environmentally friendly improved evaporative cooling systems (DEC, IEC, MEC) from the viewpoint of heat stress in poultry houses. Thermodynamic analysis of these systems was carried out for the climatic conditions of Multan, Pakistan. The results appreciably controlled the environmental conditions which showed that for the months of April, May, and June, the decrease in temperature by direct evaporative cooling (DEC), indirect evaporative cooling (IEC), and Maisotsenko-Cycle evaporative cooling (MEC) systems is 7–10 °C, 5–6.5 °C, and 9.5–12 °C, respectively. In case of July, August, and September, the decrease in temperature by DEC, IEC, and MEC systems is 5.5–7 °C, 3.5–4.5 °C, and 7–7.5 °C, respectively. In addition, drop in temperature-humidity index (THI) values by DEC, IEC, and MEC is 3.5–9 °C, 3–7 °C, and 5.5–10 °C, respectively for all months. Optimum temperature and relative humidity conditions are determined for poultry birds and thereby, systems’ performance is thermodynamically evaluated for poultry farms from the viewpoint of THI, temperature-humidity-velocity index (THVI), and thermal exposure time (ET). From the analysis, it is concluded that MEC system performed relatively better than others due to its ability of dew-point cooling and achieved THI threshold limit with reasonable temperature and humidity indexes.

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