Dynamic Performance Investigation of Single-Effect NH3 + LiNO3 and NH3 + NaSCN Solar Cooling Cycles: A Case Study for Western Indian Climate

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Nishant Modi ◽  
Bhargav Pandya ◽  
Vinay Kumar ◽  
Jatin Patel
Keyword(s):  
Dynamic Performance ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Sodium Thiocyanate ◽  
Lithium Nitrate ◽  
Ambient Conditions ◽  
Evaporator Temperature ◽  
Water Storage Tank ◽  
Single Effect

Abstract This article compares the dynamic behavior of solar-assisted novel salt-based ammonia/sodium thiocyanate (NH3 + NaSCN) and ammonia/lithium nitrate (NH3 + LiNO3) single-effect absorption refrigeration cycles. An evacuated tube collector (ETC) is attached with fully mixed hot water storage tank to power the absorption system. Variations in ambient conditions are determined for Gujarat Region of India and their effects on absorption cycles are quantified throughout the days for the months of April to September. System performance is investigated and compared on terms of coefficient of performance (COP), refrigeration capacity, efficiency and solar COP (SCOP). At same operating conditions, it is found that the NH3 + LiNO3 cycle can achieve much lower evaporator temperature (−13.1 °C) then NH3 + NaSCN cycle (−7.5 °C) and maximum possible COP for NH3 + NaSCN cycle is 0.73 and 0.68 for NH3 + LiNO3 cycle. The working limit of NH3 + LiNO3 cycle is wide ranging and narrow for NH3 + NaSCN cycle due to high crystallization possibility. SCOP varies from 0.18 to 0.43 for NH3 + NaSCN cycle and 0.17 to 0.39 for NH3 + LiNO3 cycle over the period of 6 months. Based on these findings, the suitable working cycle is justified.

scholarly journals Comparison of Transcritical CO2 and Conventional Refrigerant Heat Pump Water Heaters for Domestic Applications

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 479
Author(s):  
Ignacio Paniagua ◽  
Ángel Álvaro ◽  
Javier Martín ◽  
Celina Fernández ◽  
Rafael Carlier
Keyword(s):  
Heat Pump ◽  
Thermodynamic Cycle ◽  
Heat Pumps ◽  
Design Tool ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Ambient Conditions ◽  
Water Heater ◽  
Water Heaters

Although CO 2 as refrigerant is well known for having the lowest global warming potential (GWP), and commercial domestic heat pump water heater systems exist, its long expected wide spread use has not fully unfolded. Indeed, CO 2 poses some technological difficulties with respect to conventional refrigerants, but currently, these difficulties have been largely overcome. Numerous studies show that CO 2 heat pump water heaters can improve the coefficient of performance (COP) of conventional ones in the given conditions. In this study, the performances of transcritical CO 2 and R410A heat pump water heaters were compared for an integrated nearly zero-energy building (NZEB) application. The thermodynamic cycle of two commercial systems were modelled integrating experimental data, and these models were then used to analyse both heat pumps receiving and producing hot water at equal temperatures, operating at the same ambient temperature. Within the range of operation of the system, it is unclear which would achieve the better COP, as it depends critically on the conditions of operation, which in turn depend on the ambient conditions and especially on the actual use of the water. Technology changes on each side of the line of equal performance conditions of operation (EPOC), a useful design tool developed in the study. The transcritical CO 2 is more sensitive to operating conditions, and thus offers greater flexibility to the designer, as it allows improving performance by optimising the global system design.

Investigation of an Energy Source Temperature for NH3 + NaSCN and NH3 + LiNO3 Absorption Refrigeration Systems

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Nishant Modi ◽  
Bhargav Pandya ◽  
Jatin Patel
Keyword(s):  
Energy Source ◽  
Minimum Energy ◽  
Critical Energy ◽  
Maximum Energy ◽  
Coefficient Of Performance ◽  
Sodium Thiocyanate ◽  
Lithium Nitrate ◽  
Absorption Refrigeration ◽  
Evaporator Temperature ◽  
Source Temperature

Abstract This paper evaluates the energy source temperature for novel salts based ammonia/sodium thiocyanate (NH3 + NaSCN) and ammonia/lithium nitrate (NH3 + LiNO3) absorption refrigeration systems. Minimum energy source temperature (cutoff) required to initiate the cooling, critical energy source temperature for optimized thermodynamic performance and possible maximum energy source temperature to avoid crystallization have been determined, and empirical correlations are developed to facilitate continuous operation of the system. A comparison of cutoff energy source temperature depicts that the NH3 + NaSCN pair requires averagely 6 –7 °C higher cutoff temperature compared with the NH3 + LiNO3 pair. Contradictory to this, the maximum coefficient of performance (COP) of the NH3 + NaSCN pair is 7.02% higher than that the NH3 + LiNO3 pair. However, NH3 + NaSCN pair operates in a very narrow range of energy source temperature. From the P − T − X diagram, the crystallization phenomenon is clarified and the maximum energy source temperature has been determined beyond which the system would not function due to crystallization problems. For −10 °C evaporator temperature, the energy source temperature should be controlled between 87 °C and 115 °C for the NH3 + NaSCN pair and between 80 °C and 147 °C for the NH3 + LiNO3 pair.

scholarly journals Installation and Operation of a Solar Cooling and Heating System Incorporated with Air-Source Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 996 ◽  
Author(s):  
Li Huang ◽  
Rongyue Zheng ◽  
Udo Piontek
Keyword(s):  
Heating System ◽  
Cooling Capacity ◽  
Heat Pumps ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Energy Yield ◽  
Absorption Chiller ◽  
Annual Average ◽  
Water Storage Tank ◽  
Solar Cooling

A solar cooling and heating system incorporated with two air-source heat pumps was installed in Ningbo City, China and has been operating since 2018. It is composed of 40 evacuated tube modules with a total aperture area of 120 m2, a single-stage and LiBr–water-based absorption chiller with a cooling capacity of 35 kW, a cooling tower, a hot water storage tank, a buffer tank, and two air-source heat pumps, each with a rated cooling capacity of 23.8 kW and heating capacity of 33 kW as the auxiliary system. This paper presents the operational results and performance evaluation of the system during the summer cooling and winter heatingperiod, as well as on a typical summer day in 2018. It was found that the collector field yield and cooling energy yield increased by more than 40% when the solar cooling and heating system is incorporated with heat pumps. The annual average collector efficiency was 44% for cooling and 42% for heating, and the average coefficient of performance (COP) of the absorption chiller ranged between 0.68 and 0.76. The annual average solar fraction reached 56.6% for cooling and 62.5% for heating respectively. The yearly electricity savings accounted for 41.1% of the total electricity consumption for building cooling and heating.

INFLUENCE OF THE SOLUTION HEAT EXCHANGER EFFICIENCY ON THE PERFORMANCE OF A SINGLE EFFECT H2O-LiBr ADIABATIC ABSORPTION SYSTEM

2011 ◽  
Vol 19 (02) ◽  
pp. 107-112 ◽  
Author(s):  
GEYDY GUTIÉRREZ URUETA ◽  
PEDRO RODRÍGUEZ AUMENTE ◽  
MARIA RODRÍGUEZ HIDALGO ◽  
ANTONIO LECUONA NEUMANN
Keyword(s):  
Heat Exchanger ◽  
Strong Solution ◽  
Heat Transfer Process ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Test Facility ◽  
Absorption System ◽  
Experimental Conditions ◽  
Single Effect ◽  
Absorption Cycle

This work analyzes the effect that particular operating conditions of a single effect H2O - LiBr adiabatic absorption system have on a plate-type solution heat exchanger efficiency. The corresponding influence of such efficiency on the performance of facility under study is evaluated. As a result of the design of experimental test facility, the functioning of the strong solution circuit leads to take into account some particular operating conditions which affect the correct performance of the solution heat exchanger. For some experimental conditions, the strong solution side is not completely filled by the solution fluid. As a consequence of this, the heat transfer process is affected, reducing the solution heat exchanger efficiency and changing greatly the resulting coefficient of performance (COP) of the absorption facility. In order to illustrate this phenomenon, this paper offers graphical results including: solution working temperatures, solution heat exchanger efficiency and COP in a time sequence of an experiment, as well as for fixed steady-state operating conditions. These results show the importance of a correct functioning of the solution heat exchanger on the performance of an absorption system. The results are useful for researchers interested in new absorption cycle designs.

Experimental Analysis of Newly Designed Solar Assisted Single Effect Absorption Cooling System of 5.25 kW Cooling Capacity for Domestic Use

2015 ◽  
Vol 787 ◽  
pp. 32-36 ◽  
Author(s):  
V.Boopathi Raja ◽  
V. Shanmugam
Keyword(s):  
Cooling System ◽  
Cooling Capacity ◽  
Hot Water ◽  
Operational Parameters ◽  
Water Storage Tank ◽  
Absorption Cooling ◽  
Domestic Use ◽  
Single Effect ◽  
Absorption Cooling System ◽  
Vapour Compression

Many research studies have been carried out to develop small capacity absorption cooling systems as an alternative to conventional vapour compression refrigeration (VCR) systems with respect to performance and economic aspects. The aim of this work is to design a solar assisted single effect absorption cooling system of 5.25 kW cooling capacity to cool a room having floor area of 15 m2. Based on the design, an experimental setup is constructed and operated by supplying heat to the generator using solar energy. The performance analysis of the cooling system is carried out by measuring the various operational parameters. The minimum cooling temperature of 16°C is observed in the evaporator and maximum COP of 0.9 is obtained when the hot water storage tank reaches 90°C. As per this new design, the operational cost is minimized and the COP obtained is slightly higher when compared to that of earlier similar works.

Optimization Process of a Visi-Cooler Using Ternary Mixtures of R134a and Hydrocarbons

2017 ◽  
Vol 25 (02) ◽  
pp. 1750019 ◽  
Author(s):  
Srinivas Pendyala ◽  
Ravi Prattipati ◽  
A V Sita Rama Raju
Keyword(s):  
Ozone Depletion ◽  
Operating Conditions ◽  
Ternary Mixtures ◽  
Coefficient Of Performance ◽  
Optimum Operating ◽  
Taguchi Technique ◽  
Capillary Length ◽  
Evaporator Temperature ◽  
Safe Limit ◽  
Air Conditioning Systems

Ozone depletion and global warming phenomenon necessitates the replacement of widely used refrigerants which consist of chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) in refrigeration and air-conditioning systems. In this paper, experimental analysis on the performance of hydrofluorocarbon/hydrocarbon (HFC/HC) mixture as a possible drop-in replacement for R134a refrigerant is presented. The influence of capillary length, composition of the mixture and refrigerant charge at various evaporator temperatures on coefficient of performance (COP) are investigated. The optimum operating conditions are obtained by applying Taguchi technique for the acquired experimental results. The results of analysis of variance indicated that for a given evaporator temperature, HFC/HC mixture charge amount is the most influencing parameter. At the optimum condition, the simulation showed that the amount of charge required for HFC/HC mixture in visi-cooler is 120[Formula: see text]g which is 50% lower than required quantity of R134a for the same system. The HC mixture quantity amounted to 90[Formula: see text]g in the HFC/HC mixture which is lower than the safe limit of 150[Formula: see text]g. This eliminates the risk of flammability of HC in the proposed mixture while reducing the quantity of R134a by 87.5%.

Design and Modeling of One Refrigeration Ton Solar Assisted Adsorption Air Conditioning System

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
M. Alkhair ◽  
M. Y. Sulaiman ◽  
K. Sopian ◽  
C. H. Lim ◽  
E. Salleh ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Hot Water ◽  
Activated Carbon Fiber ◽  
Coefficient Of Performance ◽  
Weather Data ◽  
Adsorption System ◽  
Water Storage Tank ◽  
Chilled Water

The modeling of the performance of a one refrigeration ton (RT) solar assisted adsorption air-conditioning refrigeration system using activated carbon fiber/ethanol as the adsorbent/adsorbate pair has been undertaken in this study. The effects of hot water, cooling water, chilled water inlet temperatures, and hot water and chilled water flow rates were taken into consideration in the optimization of the system and in the design of the condenser, evaporator, and hot water storage tank. The study includes analysis of the weather data and its effect on both the adsorption system and the cooling load. This is then followed by estimation of the cooling capacity and coefficient of performance (COP) of the adsorption system as a function of the input parameters. The results of the model will be compared to experimental data in a next step.

scholarly journals Numerical Simulations of Temperature and Velocity Fields in the Storage Tank with the Three-Coil Heat Exchanger

2020 ◽  
Vol 44 (3) ◽  
pp. 74-79
Author(s):  
Robert Smusz ◽  
Joanna Wilk ◽  
Paweł Bałon
Keyword(s):  
Numerical Simulations ◽  
Storage Tank ◽  
Thermal Stratification ◽  
Waste Heat ◽  
Velocity Fields ◽  
Operating Conditions ◽  
Hot Water ◽  
Water Storage Tank ◽  
Coil Heat Exchanger ◽  
Temperature And Velocity Fields

AbstractThis article presents the results of the numerical investigation of the thermal stratification in the hot water storage tank. The exchanger consists of three tube coils that are immersed in the storage tank of hot water. Two coils—lower and upper—are designed to warm the water in the tank using the water as a heating medium. Another coil—uses the refrigerant for the waste heat transfer. The temperature stratification device is mounted in the thermal storage tank. The device’s task is to improve the thermal stratification level of heated water. The performed numerical simulations allowed us to obtain the temperature and velocity fields in the storage tank under the conditions of the work of coils filled with water. Calculations were made in the case of the use of the stratification device under the operating conditions of the upper and lower coils with water.

Performance Analyses of Photovoltaic Thermal Integrated Concentrator Collector Combined With Single Effect Absorption Cooling Cycle: Constant Flow Rate Mode

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Md. Meraj ◽  
M.E. Khan ◽  
Md. Azhar
Keyword(s):  
Climatic Conditions ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Design Parameters ◽  
Inlet Temperature ◽  
New Delhi ◽  
Absorption System ◽  
Simulation Code ◽  
Single Effect ◽  
Performance Analyses

Abstract In the present communication, performance analyses of interconnected N number of fully covered semitransparent photovoltaic thermal integrated concentrator collectors combined with single effect vapor absorption refrigeration system have been carried out. The proposed system was analyzed under the constant mass flowrate of collectors’ fluid. Mathematical expressions have also been derived for generator temperature of the absorption unit as a function of both design and operating parameters. Further, simulations have been performed for a typical day of May month of New Delhi climatic conditions. Performance parameters have been evaluated such as collector exit temperature, generator inlet temperature, electrical power output, electrical efficiency, overall thermal energy gain, instantaneous thermal efficiency, overall exergy gain and coefficient of performance of the absorption system. The simulation code has been written in matlab. From the present analyses, the following salient conclusions have been drawn: Operating generator temperature of the absorption system is suitable for five number of photovoltaic thermal-integrated parabolic concentrator collector connected in series. The proposed system will continue operating for 5 h during May month in New Delhi climate conditions. The maximum solar coefficient of performance, refrigeration coefficient of performance, and exergy coefficient of performance are reported as 0.1551, 0.8344, and 0.2697, respectively, for the proposed novel system under given design and operating conditions. Additionally, the effects of other design parameters of this novel system have also been investigated.

scholarly journals Dynamic experimental analysis of a LiBr/H2O single effect absorption chiller with nominal capacity of 35 kW of cooling

2019 ◽  
Vol 41 (1) ◽  
pp. 35173 ◽  
Author(s):  
Alvaro Antonio Ochoa Villa ◽  
José Carlos Charamba Dutra ◽  
Jorge Recarte Henríquez Henríquez ◽  
Carlos Antonio Cabral do Santos ◽  
José Ângelo Peixoto da Costa
Keyword(s):  
Thermal Load ◽  
Heat Dissipation ◽  
Cold Water ◽  
Operating Conditions ◽  
Hot Water ◽  
Experimental Methodology ◽  
Absorption Chiller ◽  
Water Heater ◽  
Nominal Capacity ◽  
Single Effect

This work aims to transient performance of chiller single effect absorption refrigeration using the LiBr/H2O pair with nominal capacity of 35 kW. The goal of this study is to verify the absorption chiller when subjected to thermal loads and it transiently responsive as a function of the temperatures of the chilled, hot and cold water of the system. An experimental methodology was established in a micro-CHP laboratory to simulate the dynamic operating conditions of the system considering the thermal load (chilled water), the activation source (hot water) and the heat dissipation circuit (cold water). The thermal load was simulated from a set of electrical resistors installed in a water heater and the activation of the chiller from recovery gas a microturbine 30 kW and through a compact heat exchanger, where water is heated and stored in a hot buffer tank. The absorption chiller heat dissipation system consists of the pump and cooling tower. The system responded appropriately to the thermal load imposed providing COP values in the transient regime of 0.55 to 0.70 the temperature conditions tested.

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