Climatic Effect on the Exergetic Performance of Conventional to Hybrid Evaporative Coolers with Varying Dead State Temperatures in India

2021 ◽  
pp. 1-33
Author(s):  
V Venkateswara Rao ◽  
Santanu Prasad Datta
Keyword(s):  
Air Conditioning ◽  
Sustainability Assessment ◽  
Cooling System ◽  
Exergy Efficiency ◽  
Exergy Destruction ◽  
Direct Expansion ◽  
Dead State ◽  
Evaporative Cooling System ◽  
Expansion Cooling ◽  
Semi Arid

Abstract A comprehensive exergy, exergo-economic and sustainability assessment of seven conventional to hybrid air-conditioning systems comprising direct and indirect evaporative coolers with direct expansion system, and their several combinations integrated into an 8-story domestic building for 5 different cities corresponding to arid, semi-arid, humid sub-tropical, tropical wet and dry, and tropical wet climatic zones across India are investigated based on simulation output from EnergyPlus. The exergetic performances are reported for varying dead state temperatures ranging from 5°C to 40°C while saturated humidity ratio and pressure at system outlet are two other dead state properties. The results reveal that the specific exergy of moist air and exergetic efficiency decrease with increasing dead state temperature and become least at a dead state temperature near to American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) comfort temperature of 23°C. In arid, semi-arid and humid subtropical climates, the three-stage evaporative cooling system exhibited the lowest exergy destruction of 100 J kg−1 and the highest exergy efficiency of 90% at a dead state temperature of 40°C. The two-stage direct evaporative-direct expansion cooling system exhibited superior exergy efficiency of around 90% in tropical wet and dry and tropical wet zones. Further, the Grassmann diagram based on the climate of Hyderabad indicated that the three-stage cooling system is energetically and exergetically optimum with exergy destruction of 28.86%.

Applicability Research on Evaporative Cooling Technology in Hunan Province

2014 ◽  
Vol 1070-1072 ◽  
pp. 1679-1683
Author(s):  
Qin Ouyang ◽  
Guang Xiao Kou ◽  
Min Ouyang
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Waste Heat ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Hunan Province ◽  
Design Parameters ◽  
Climate Conditions ◽  
Energy Saving Potential ◽  
Evaporative Cooling System

According to the climate conditions of Hunan province and the design parameters related to air conditioning, the energy consumption and the related characteristics of the liquid desiccant evaporative cooling system (LDECS) are compared with primary return air conditioning system. The results show that energy consumption of LDECS can be decreased by 11.78% compared to the primary return air system. LDECS has a certain degree of energy saving potential in Hunan province, especially when waste heat is available.

scholarly journals A MATHEMATICAL MODEL FOR DIRECT EVAPORATIVE COOLING AIR CONDITIONING SYSTEM

2003 ◽  
Vol 2 (2) ◽  
Author(s):  
J. R. Camargo ◽  
C. D. Ebinuma ◽  
S. Cardoso
Keyword(s):  
Mathematical Model ◽  
Air Conditioning ◽  
Cooling System ◽  
Convective Heat Transfer Coefficient ◽  
Evaporative Cooling ◽  
Experimental Tests ◽  
Water Evaporation ◽  
Human Thermal Comfort ◽  
Direct Evaporative Cooling ◽  
Evaporative Cooling System

Air conditioning systems are responsible for increasing men's work efficiency as well for his comfort, mainly in the warm periods of the year. Currently, the most used system is the mechanical vapor compression system. However, in many cases, evaporative cooling system can be an economical alternative to replace the conventional system, under several conditions, or as a pre-cooler in the conventional systems. It leads to a reduction in the operational cost, comparing with systems using only mechanical refrigeration. Evaporative cooling operates using induced processes of heat and mass transfer, where water and air are the working fluids. It consists in water evaporation, induced by the passage of an air flow, thus decreasing the air temperature. This paper presents the basic principles of the evaporative cooling process for human thermal comfort, the principles of operation for the direct evaporative cooling system and the mathematical development of the equations of thermal exchanges, allowing the determination of the effectiveness of saturation. It also presents some results of experimental tests in a direct evaporative cooler that take place in the Air Conditioning Laboratory at the University of Taubaté Mechanical Engineering Department, and the experimental results are used to determinate the convective heat transfer coefficient and to compare with the mathematical model.

scholarly journals Energy and Exergy Analyses of Adsorption Chiller at Various Recooling-Water and Dead-State Temperatures

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2172
Author(s):  
Ahmad A. Alsarayreh ◽  
Ayman Al-Maaitah ◽  
Menwer Attarakih ◽  
Hans-Jörg Bart
Keyword(s):  
Water Temperature ◽  
Recovery Time ◽  
Exergy Efficiency ◽  
Exergy Destruction ◽  
Adsorption Chiller ◽  
Dead State ◽  
Energy And Exergy ◽  
The Dead ◽  
Exergy Analyses ◽  
Mass Recovery

We conducted energy and exergy analyses of an adsorption chiller to investigate the effect of recooling-water temperatures on the cooling capacity and Coefficient of Performance (COP) with variable cycle modes. We investigated both the effect of the recooling-water temperature and the dead state temperature on the exergy destruction in the chiller components. Our results show that there is an optimum reheat cycle mode for each recooling-water temperature range. For the basic single stage cycle, the exergy destruction is mainly accrued in the desorber (49%), followed by the adsorber (27%), evaporator (13%), condenser (9%), and expansion valve (2%). The exergy destruction for the preheating process is approximately 35% of the total exergy destruction in the desorber. By contrast, the precooling process is almost 58% of the total exergy destruction in the adsorber. The exergy destruction decreases when increasing the recooling-water and the dead state temperatures, while the exergy efficiency increases. Nonetheless, the exergy efficiency decreases with an increase in the recooling-water temperature at fixed dead state temperatures. The effect of the mass recovery time in the reheat cycle on exergy destruction was also investigated, and the results show that the exergy destruction increases when the mass recovery time increases. The exergy destruction in the adsorbent beds was the most sensitive to the increase in mass recovery time.

scholarly journals Exergy and Energy Analyses of Dual-Temperature Evaporator Split AC System Incorporated A Capillary Tube and A Two-Phase Ejector

2020 ◽  
Vol 77 (1) ◽  
pp. 88-99
Author(s):  
Made Ery Arsana ◽  
I Gusti Bagus Wijaya Kusuma ◽  
Made Sucipta ◽  
I Nyoman Suamir
Keyword(s):  
Numerical Model ◽  
Experimental Test ◽  
Air Conditioning ◽  
Capillary Tube ◽  
Test System ◽  
Exergy Efficiency ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Two Phase ◽  
Better Than

This study was aimed to investigate performance of a split type air conditioning (SAC) system applying exergy destruction method. A numerical model was established based on exergy destruction analysis of a Condenser Outlet Split-Split Air Conditioning (COS-SAC) system integrated with dual-temperature evaporator and incorporated capillary tube and ejector as expansion devices. An experimental test system was also established to experimentally validate the model. Two type of refrigerants R-290 and R-22 were involved in the evaluations. The Coefficient of Performance (COP) of the ejector COS-SAC system, exergy destruction, and exergy efficiency were determined and compared with those in the SAC system utilizing capillary tube. The results showed there was a significant improvement in the overall exergy efficiency of the COS-SAC systems. The COP of the COS-SAC system was also found to be better than the COP of the SAC system.

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.

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