Hybrid Ammonia Water Absorption System of Small and Medium Capacity

2003 ◽  
Author(s):  
Florea Chiriac ◽  
Robert Gavriliuc ◽  
Rodica Dumitrescu ◽  
Anica Ilie ◽  
Cristina Piˆrvu
Keyword(s):  
Water Solution ◽  
Electrical Energy ◽  
Cooling Capacity ◽  
Hot Water ◽  
Experimental Comparison ◽  
Maximum Temperature ◽  
Absorption System ◽  
Transfer Coefficients ◽  
Ammonia Water ◽  
Micro Channels

The paper presents an absorption system with compact heat exchangers (micro-channels), working with ammonia water solution, driven by either solar or electrical energy. The construction of the solar panels includes heat pipes, and they are able to provide hot water with a maximum temperature of 130°C. The cooling capacity of the system ranges from 5 to 10 kW. The system is designed for comfort the technological air conditioning, providing inside air temperatures in the range of 10°C to 20°C. The project promotes ammonia as an ecological and natural refrigerant and aims to experimentally evaluate the thermal performances of each component of the system (condenser, evaporator, absorber and vapor generator) and of the entire system. The next step consists in a theoretical versus experimental comparison of data. The thermal performances refer to heat transfer coefficients in micro-channels on water ammonia side, as well as on the airside, and to the performance coefficient for various working conditions.

scholarly journals Energy and Cost Analysis and Optimization of a Geothermal-Based Cogeneration Cycle Using an Ammonia-Water Solution: Thermodynamic and Thermoeconomic Viewpoints

2020 ◽  
Vol 12 (2) ◽  
pp. 484 ◽  
Author(s):  
Nima Javanshir ◽  
Seyed Mahmoudi S. M. ◽  
M. Akbari Kordlar ◽  
Marc A. Rosen
Keyword(s):  
Water Solution ◽  
Unit Cost ◽  
Exergy Efficiency ◽  
Hot Water ◽  
Cycle Performance ◽  
Working Fluid ◽  
Kalina Cycle ◽  
Ammonia Water ◽  
Total Product ◽  
Cogeneration Cycle

A cogeneration cycle for electric power and refrigeration, using an ammonia-water solution as a working fluid and the geothermal hot water as a heat source, is proposed and investigated. The system is a combination of a modified Kalina cycle (KC) which produces power and an absorption refrigeration cycle (ARC) that generates cooling. Geothermal water is supplied to both the KC boiler and the ARC generator. The system is analyzed from thermodynamic and economic viewpoints, utilizing Engineering Equation Solver (EES) software. In addition, a parametric study is carried out to evaluate the effects of decision parameters on the cycle performance. Furthermore, the system performance is optimized for either maximizing the exergy efficiency (EOD case) or minimizing the total product unit cost (COD case). In the EOD case the exergy efficiency and total product unit cost, respectively, are calculated as 34.7% and 15.8$/GJ. In the COD case the exergy efficiency and total product unit cost are calculated as 29.8% and 15.0$/GJ. In this case, the cooling unit cost, c p , c o o l i n g , and power unit cost, c p , p o w e r , are achieved as 3.9 and 11.1$/GJ. These values are 20.4% and 13.2% less than those obtained when the two products are produced separately by the ARC and KC, respectively. The thermoeconomic analysis identifies the more important components, such as the turbine and absorbers, for modification to improve the cost-effectiveness of the system.

scholarly journals Heat-transfer characteristics of ammonia-water falling film generation outside a vertical tube

2017 ◽  
Vol 21 (3) ◽  
pp. 1251-1259 ◽  
Author(s):  
Chao Luo ◽  
Jun Zhao ◽  
Weibin Ma
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Water Temperature ◽  
Water Solution ◽  
Hot Water ◽  
Falling Film ◽  
Ammonia Water ◽  
Overall Heat Transfer Coefficient ◽  
Spray Density

A heat transfer experimental of vertical out-tube falling film was conducted with different inlet spray density of ammonia-water solution and inlet hot water temperature. The inlet liquid mass concentration was selected as 60% of ammonia. The experiments showed that the overall heat transfer coefficient increases with the increase of inlet spray density and a maximum overall heat transfer coefficient could be obtained in an optimum spray density of ammonia-water solution, ?, between 0.26 and 0.29 kg/ms. The generation of ammonia vapor outside the vertical falling film had a similar trend with the overall heat transfer coefficient basing on different spray density. The effect of hot water temperature difference, ?T, on overall heat transfer coefficient showed that ?T between 10 and 13 K is the optimum temperature difference of the vertical falling film generation

Study of the Cooling Performance of a Mist-Type Regenerative Evaporative Cooler Under Different Feed Water Temperature

2020 ◽  
Vol 28 (02) ◽  
pp. 2050011
Author(s):  
B. S. Arun ◽  
V. Mariappan
Keyword(s):  
Water Temperature ◽  
Water Solution ◽  
Water Film ◽  
Cooling Capacity ◽  
Hot Water ◽  
Feed Water ◽  
Liquid Desiccant ◽  
Cooling Performance ◽  
Evaporative Cooler ◽  
Feed Water Temperature

In hot and humid climates, evaporative cooler is coupled with desiccant dehumidifier to obtain effective cooling. To realize the M-cycle-based cooler which combines liquid desiccant regeneration and evaporative cooling in a single apparatus, the effect of different feed water temperature on cooling performance is investigated in this paper. It was observed that wetting water film layer of conventional regenerative evaporative cooler (REC) carries a significant amount of sensible heat from the hot water/solution which reduced the wet-bulb effectiveness of the cooler. To enhance its effectiveness, an ultrasonic atomization mist REC was proposed. The influence of different intake conditions on cooling performance was studied and found that mist REC performed better than conventional cooler for higher feed water temperature. The wet-bulb effectiveness of the cooler ranged from 0.56 to 1.15 with maximum cooling capacity of 580[Formula: see text]W, which is comparable to the previous studies. This prototype can be further developed to an ultrasonic liquid desiccant waterless evaporative cooler.

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.

Thermodynamic analysis of triple effect ammonia–water absorption compression (hybrid) cycle

2021 ◽  
pp. 095440892199568
Author(s):  
CP Jawahar
Keyword(s):  
Water Absorption ◽  
Energy Analysis ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Performance Parameters ◽  
Evaporator Temperature ◽  
Ammonia Water ◽  
Absorption Cycle ◽  
Hybrid Cycle

This paper presents the energy analysis of a triple effect absorption compression (hybrid) cycle employing ammonia water as working fluid. The performance parameters such as cooling capacity and coefficient of performance of the hybrid cycle is analyzed by varying the temperature of evaporator from −10 °C to 10 °C, absorber and condenser temperatures in first stage from 25 °C to 45 °C, degassing width in both the stages from 0.02 to 0.12 and is compared with the conventional triple effect absorption cycle. The results of the analysis show that the maximum cooling capacity attained in the hybrid cycle is 472.3 kW, at 10 °C evaporator temperature and first stage degassing width of 0.12. The coefficient of performance of the hybrid cycle is about 30 to 65% more than the coefficient of performance of conventional triple effect cycle.

scholarly journals Thermal Injuries Caused by Water from Loose Garden Hoses

2021 ◽  
Vol 8 ◽  
pp. 2333794X2110312
Author(s):  
Karolína Uhrová ◽  
Pavel Böhm
Keyword(s):  
Human Skin ◽  
Air Temperature ◽  
Concrete Surface ◽  
Hot Water ◽  
Maximum Temperature ◽  
Water Contact ◽  
Valid Data ◽  
Thermal Injuries

This is a monitoring research, the purpose of which is to point out the danger of scalding with water from loose garden hoses. All the stated data are the result of this research, which occurred during the month of August. To adequately compare the maximum temperature that the water reaches in garden hoses exposed to sunlight, 2 different surfaces were chosen, namely grass and concrete. It has been found that water in garden hoses, which lie in a place exposed to sunlight, is able to reach temperatures at which, in case of contact with human skin, there is a risk of scalding. The results confirmed the assumption that the temperature in the grass will be lower in the hoses than in the concrete surface. At an air temperature of 35°C, the water in the hoses on the grass reached a temperature of up to 47.3°C. On a concrete surface at an air temperature of 28.5°C, the water in the hoses reached 49.8°C. There is a risk of scalding from such hot water contact with the skin, and especially with sensitive baby skin. The aim of this research is to provide valid data on the risk of spilling hyperthermic water in free-lying garden hoses exposed to sunlight. The threat of scalding can occur unknowingly or through negligence, the risk of scalding with such water increases during tropical days significantly.

scholarly journals Experimental Comparison of Innovative Composite Sorbents for Space Heating and Domestic Hot Water Storage

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 476
Author(s):  
Vincenza Brancato ◽  
Larisa G. Gordeeva ◽  
Angela Caprì ◽  
Alexandra D. Grekova ◽  
Andrea Frazzica
Keyword(s):  
Silica Gel ◽  
Xrd Analysis ◽  
Complete Characterization ◽  
Operating Conditions ◽  
Hot Water ◽  
Experimental Comparison ◽  
Space Heating ◽  
Calorimetric Analysis ◽  
Domestic Hot Water ◽  
Composite Sorbents

In this study, the development and comparative characterization of different composite sorbents for thermal energy storage applications is reported. Two different applications were targeted, namely, low-temperature space heating (SH) and domestic hot water (DHW) provision. From a literature analysis, the most promising hygroscopic salts were selected for these conditions, being LiCl for SH and LiBr for DHW. Furthermore, two mesoporous silica gel matrixes and a macroporous vermiculite were acquired to prepare the composites. A complete characterization was performed by investigating the porous structure of the composites before and after impregnation, through N2 physisorption, as well as checking the phase composition of the composites at different temperatures through X-ray powder diffraction (XRD) analysis. Furthermore, sorption equilibrium curves were measured in water vapor atmosphere to evaluate the adsorption capacity of the samples and a detailed calorimetric analysis was carried out to evaluate the reaction evolution under real operating conditions as well as the sorption heat of each sample. The results demonstrated a slower reaction kinetic in the vermiculite-based composites, due to the larger size of salt grains embedded in the pores, while promising volumetric storage densities of 0.7 GJ/m3 and 0.4 GJ/m3 in silica gel-based composites were achieved for SH and DHW applications, respectively.

scholarly journals AUDIT ENERGI PADA SEBUAH HOTEL

2012 ◽  
Vol 16 (3) ◽  
pp. 131
Author(s):  
Didik Ariwibowo
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Energy Savings ◽  
Electric Energy ◽  
Electrical Energy ◽  
Hot Water ◽  
Electrical Energy Consumption ◽  
Energy Audit ◽  
Electric Energy Consumption ◽  
Pumping System

Didik Ariwibowo, in this paper explain that energy audit activities conducted through several phases, namely: the initial audit, detailed audit, analysis of energy savings opportunities, and the proposed energy savings. Total energy consumed consists of electrical energy, fuel, and materials in this case is water. Electrical energy consumption data obtained from payment of electricity accounts for a year while consumption of fuel and water obtained from the payment of material procurement. From the calculation data, IKE hotels accounted for 420.867 kWh/m2.tahun, while the IKE standards for the hotel is 300 kWh/m2.tahun. Thus, IKE hotel included categorized wasteful in energy usage. The largest energy consumption on electric energy consumption. Largest electric energy consumption is on the air conditioning (AC-air conditioning) that is equal to 71.3%, and lighting and electrical equipment at 27.28%, and hot water supply system by 4.44%. Electrical energy consumption in AC looks very big. Ministry of Energy and Mineral Resources of the statutes, the profile of energy use by air conditioning at the hotel by 48.5%. With these considerations in the AC target for audit detail as the next phase of activity. The results of a detailed audit analysis to find an air conditioning system energy savings opportunities in pumping systems. Recommendations on these savings is the integration of automation on the pumping system and fan coil units (FCU). The principle of energy conservation in the pumping system is by installing variable speed drives (VSD) pump drive motor to adjust speed according to load on the FCU. Load variations FCU provide input on the VSD pumps to match. Adaptation is predicted pump can save electricity consumption up to 65.7%. Keywords: energy audit, IKE, AC

scholarly journals Theoretical and experimental study of a cross-flow induced-draft cooling tower

2009 ◽  
Vol 13 (4) ◽  
pp. 91-98
Author(s):  
Elazm Abo ◽  
Farouk Elsafty
Keyword(s):  
Experimental Study ◽  
Cooling Tower ◽  
Characteristic Curve ◽  
Cross Flow ◽  
Hot Water ◽  
Proper Solution ◽  
Cooling Towers ◽  
Water Cooling ◽  
Transfer Coefficients ◽  
Experimental Rig

The main objective of this study is to find a proper solution for the cross-flow water cooling tower problem, also to find an empirical correlation's controlling heat and mass transfer coefficients as functions of inlet parameters to the tower. This is achieved by constructing an experimental rig and a computer program. The computer simulation solves the problem numerically. The apparatus used in this study comprises a cross-flow cooling tower. From the results obtained, the 'characteristic curve' of cross-flow cooling towers was constructed. This curve is very helpful for designers in order to find the actual value of the number of transfer units, if the values of inlet water temperature or inlet air wet bulb temperature are changed. Also an empirical correlation was conducted to obtain the required number of transfer units of the tower in hot water operation. Another correlation was found to obtain the effectiveness in the wet bulb operation.

Sign in / Sign up

Export Citation Format

Share Document