scholarly journals Dynamic and Economic Investigation of a Solar Thermal-Driven Two-Bed Adsorption Chiller under Perth Climatic Conditions

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1005 ◽  
Author(s):  
Ali Alahmer ◽  
Xiaolin Wang ◽  
K. C. Amanul Alam
Keyword(s):  
Fourier Series ◽  
Solar Radiation ◽  
Solar Collector ◽  
Payback Period ◽  
Climatic Conditions ◽  
Solar Thermal ◽  
Coefficient Of Performance ◽  
Solar Thermal Energy ◽  
Adsorption Refrigeration ◽  
Adsorption Chiller

Performance assessment of a two-bed silica gel-water adsorption refrigeration system driven by solar thermal energy is carried out under a climatic condition typical of Perth, Australia. A Fourier series is used to simulate solar radiation based on the actual data obtained from Meteonorm software, version 7.0 for Perth, Australia. Two economic methodologies, Payback Period and Life-Cycle Saving are used to evaluate the system economics and optimize the need for solar collector areas. The analysis showed that the order of Fourier series did not have a significant impact on the simulation radiation data and a three-order Fourier series was good enough to approximate the actual solar radiation. For a typical summer day, the average cooling capacity of the chiller at peak hour (13:00) is around 11 kW while the cyclic chiller system coefficient of performance (COP) and solar system COP are around 0.5 and 0.3, respectively. The economic analysis showed that the payback period for the solar adsorption system studied was about 11 years and the optimal solar collector area was around 38 m2 if a compound parabolic collector (CPC) panel was used. The study indicated that the utilization of the solar-driven adsorption cooling is economically and technically viable for weather conditions like those in Perth, Australia.

scholarly journals Energy Analysis of a Novel Ejector-Compressor Cooling Cycle Driven by Electricity and Heat (Waste Heat or Solar Energy)

2020 ◽  
Vol 12 (19) ◽  
pp. 8178
Author(s):  
Fahid Riaz ◽  
Kah Hoe Tan ◽  
Muhammad Farooq ◽  
Muhammad Imran ◽  
Poh Seng Lee
Keyword(s):  
Low Temperature ◽  
Thermal Energy ◽  
Waste Heat ◽  
Solar Thermal ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Low Grade ◽  
Solar Thermal Energy ◽  
Temperature Heat ◽  
Vapour Compression

Low-grade heat is abundantly available as solar thermal energy and as industrial waste heat. Non concentrating solar collectors can provide heat with temperatures 75–100 °C. In this paper, a new system is proposed and analyzed which enhances the electrical coefficient of performance (COP) of vapour compression cycle (VCC) by incorporating low-temperature heat-driven ejectors. This novel system, ejector enhanced vapour compression refrigeration cycle (EEVCRC), significantly increases the electrical COP of the system while utilizing abundantly available low-temperature solar or waste heat (below 100 °C). This system uses two ejectors in an innovative way such that the higher-pressure ejector is used at the downstream of the electrically driven compressor to help reduce the delivery pressure for the electrical compressor. The lower pressure ejector is used to reduce the quality of wet vapour at the entrance of the evaporator. This system has been modelled in Engineering Equation Solver (EES) and its performance is theoretically compared with conventional VCC, enhanced ejector refrigeration system (EERS), and ejection-compression system (ECS). The proposed EEVCRC gives better electrical COP as compared to all the three systems. The parametric study has been conducted and it is found that the COP of the proposed system increases exponentially at lower condensation temperature and higher evaporator temperature. At 50 °C condenser temperature, the electrical COP of EEVCRC is 50% higher than conventional VCC while at 35 °C, the electrical COP of EEVCRC is 90% higher than conventional VCC. For the higher temperature heat source, and hence the higher generator temperatures, the electrical COP of EEVCRC increases linearly while there is no increase in the electrical COP for ECS. The better global COP indicates that a small solar collector will be needed if this system is driven by solar thermal energy. It is found that by using the second ejector at the upstream of the electrical compressor, the electrical COP is increased by 49.2% as compared to a single ejector system.

Numerical Simulation of a Novel Solar-Powered Hybrid Energy System with Cooling and Heating

2011 ◽  
Vol 374-377 ◽  
pp. 470-474
Author(s):  
Hui Long Luo ◽  
Xiao Chen ◽  
Jin Hui Peng
Keyword(s):  
Solar Radiation ◽  
Energy System ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Water Heater ◽  
Performance Simulation ◽  
Hybrid Energy System ◽  
Hybrid Energy ◽  
Solar Radiation Intensity ◽  
Solar Powered

A novel solar-powered hybrid energy system with cooling and heating is presented, which consists of an adsorption ice maker subsystem and water heater subsystem. It can be used as an ice maker and water heater hybrid system or a single water heater respectively according to incident solar radiation intensity. A numerical model is developed to predict the performances of the hybrid energy system. Performance simulation and analysis on the hybrid energy system have been made. Simulation results show that, under the climatic conditions of daily solar radiation being about 12-20MJ/m2, the hybrid energy system can be used as an ice maker and a water heater effectively, its daily solar cooling COP (coefficient of performance) is about 0.173 - 0.181, the daily heating coefficient of performance is about 0.294-0.327.

Influence of Outside Temperature on the Operation of the Adsorption Chiller

2017 ◽  
Author(s):  
Andrzej Grzebielec ◽  
Rafał Laskowski ◽  
Adam Ruciński
Keyword(s):  
Waste Heat ◽  
Experimental Studies ◽  
Coefficient Of Performance ◽  
External Parameter ◽  
Adsorption Refrigeration ◽  
Adsorption Chiller ◽  
Type Device ◽  
Lower Temperature

Adsorption refrigeration systems are characterized by a lower coefficient of performance than the compressor type device or even absorption, but can utilize waste heat at lower temperature. The aim of the study was to determine which external parameter has the greatest impact on the efficiency of the adsorption device. As a result of experimental studies there was found that this is not the temperature of the feed but particularly the temperature of external air. For this reason, it is recommended that the adsorption device should cooperate with evaporative spray coolers, instead of with popular dry coolers. This solution will increase annual efficiency of adsorption unit approx. by 25% and significantly reduce the costs of cold generation.

Two-Stage Non-Regenerative Silica Gel-Water Adsorption Refrigeration Cycle

2000 ◽  
Author(s):  
B. B. Saha ◽  
K. C. A. Alam ◽  
A. Akisawa ◽  
T. Kashiwagi ◽  
K. C. Ng ◽  
...  
Keyword(s):  
Heat Pump ◽  
Silica Gel ◽  
Water Adsorption ◽  
Waste Heat ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Adsorption Refrigeration ◽  
Two Stage ◽  
Adsorption Chiller ◽  
Adsorption Heat Pump

Abstract Over the past two decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). Closed-type, conventional adsorption refrigeration and heat pump systems have an increasing market share in Japan. In this paper, a two-stage non-regenerative, silica gel-water adsorption chiller design is outlined. Experimental measurements are performed on a prototype of a 3.5 kW rated cooling capacity adsorption heat pump in order to determine its performance under different operating temperatures (hot, cooling and chilled water). The chiller performance is analyzed in terms of cooling capacity and coefficient of performance (COP). The main innovative feature in the two-stage adsorption chiller is the ability to utilize low-temperature waste heat (∼55°C) as the driving source with a cooling source of 30°C. The technological difficulty inherent in operating a thermally activated cycle with such a small regenerating temperature lift (temperature difference between heat source and heat sink inlets) is overcome by use of a two-stage cycle.

scholarly journals Performance Results of a Solar Adsorption Cooling and Heating Unit

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1630 ◽  
Author(s):  
Tryfon C. Roumpedakis ◽  
Salvatore Vasta ◽  
Alessio Sapienza ◽  
George Kallis ◽  
Sotirios Karellas ◽  
...  
Keyword(s):  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Solar Thermal Energy ◽  
Cooling Mode ◽  
Heating Unit ◽  
Adsorption Chiller ◽  
Maximum Coefficient ◽  
Solar Powered ◽  
Evacuated Tube Collectors ◽  
Performance Results

The high environmental impact of conventional methods of cooling and heating increased the need for renewable energy deployment for covering thermal loads. Toward that direction, the proposed system aims at offering an efficient solar powered alternative, coupling a zeolite–water adsorption chiller with a conventional vapor compression cycle. The system is designed to operate under intermittent heat supply of low-temperature solar thermal energy (<90 °C) provided by evacuated tube collectors. A prototype was developed and tested in cooling mode operation. The results from the testing of separate components showed that the adsorption chiller was operating efficiently, achieving a maximum coefficient of performance (COP) of 0.65. With respect to the combined performance of the system, evaluated on a typical week of summer in Athens, the maximum reported COP was approximately 0.575, mainly due to the lower driving temperatures with a range of 75 °C. The corresponding mean energy efficiency ratio (EER) obtained was 5.8.

Phase Change Material For Solar Thermal Energy Storage In Buildings: Numerical Study

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Zineb Bouhssine ◽  
Mostafa Najam ◽  
Mustapha El Alami
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Melting Temperature ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Solar Collector ◽  
Concrete Slab ◽  
Solar Thermal ◽  
Coolant Fluid ◽  
Solar Thermal Energy

Thermal storage plays a major role in a wide variety of industrial, commercial, and residential applications when there is a mismatch between the offer and the claim of energy. In this paper, we study numerically the contribution of phase change materials (PCMs) for solar thermal energy storage (TES) in buildings. The studied configuration is a plane solar collector incorporating a PCM layer and coupled to a concrete slab (a roof of a building). The study is conducted for Casablanca (Morocco) meteorological conditions. Several simulations were performed to optimize the melting temperature and the PCM layer thickness. The results show that PCM imposes, on the roof, a temperature close to its melting temperature. The choice of a melting temperature Tmelt = 22 °C (the local indoor temperature Tc is fixed as Tc = 22 °C) limits the losses through the concrete slab, considerably. This last seems to be, nearly, adiabatic, in this case. Also, the energy released by PCM solidification, overnight, increases the outlet temperature of the coolant fluid to 35 °C and the useful flux to 80 W/m2, increasing the efficiency of the solar collector by night. The PCM functioned both as an energy storage material for the stabilization of the coolant fluid temperature and as an insulating material for the building.

A System Modeling Approach for Active Solar Heating and Cooling System With Phase Change Material (PCM) for Small Buildings

2012 ◽  
Author(s):  
Rajeevan Ratnanandan ◽  
Jorge E. González
Keyword(s):  
Phase Change ◽  
Thermal Energy ◽  
Cooling System ◽  
Hot Water ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Adsorption Chiller ◽  
Heating And Cooling ◽  
Solar Thermal Collectors ◽  
Change Material

The paper presents a study of the performance of an active solar thermal heating and cooling system for small buildings. The work is motivated by the need for finding sustainable alternatives for building applications that are climate adaptable. The energy demand for heating and cooling needs in residential and light commercial buildings in mid-latitudes represent more than 50% of the energy consumed annually by these buildings. Solar thermal energy represents an untapped opportunity to address this challenge with sustainable solutions. Direct heating could be a source for space heating and hot water, and for heat operated cooling systems to provide space cooling. However, a key limitation in mainstreaming solar thermal for heating and cooling has been the size of thermal storage to implement related technologies. We address this issue by coupling a Phase Change Material (PCM) with an adsorption chiller and a radiant flooring system for year round solar thermal energy utilization in Northern climates. The adsorption chiller allows for chill water production driven by low temperature solar thermal energy for summer cooling, and low temperature radiant heating provides for space heating in winter conditions, while hot water demand is supplied year round. These active systems are operated by high performance solar thermal collectors. The PCM has been selected to match temperatures requirements of the adsorption chiller, and the tank was designed to provide three levels of temperatures for all applications; cooling, heating, and hot water. The material selection is paraffin sandwiched with a graphite matrix to increase the conductivity. The specific objective of the preset work is to provide a system optimization of this active system. The system is represented by a series of mathematical models for each component; PCM tank with heat exchangers, the adsorption machine, the radiant floor, and the solar thermal collectors (Evacuated tubular collectors). The PCM modeling allows for sensible heating, phase change process, and superheating. Parametric simulations are conducted for a defined small building in different locations in US with the objective of defining design parameters for; optimal solar collector array, sizing of the PCM tank, and performance of the adsorption machine and radiant heating system. The monthly and annual solar fractions of the system are also reported.

scholarly journals Preliminary Results on Experimental Modelling of an Adsorption Chiller

2021 ◽  
Vol 6 ◽  
pp. 29
Author(s):  
Nayrana Daborer-Prado ◽  
Alois Resch
Keyword(s):  
Numerical Model ◽  
Water Cycle ◽  
Cooling System ◽  
Numerical Study ◽  
Lumped Parameter Model ◽  
Coefficient Of Performance ◽  
Adsorption Refrigeration ◽  
Experimental Modelling ◽  
Adsorption Chiller ◽  
Lumped Parameter

Adsorption refrigeration, as a renewable cooling method, has received more attention in the last few years. The interest in this technology comes especially from developing and tropical countries, where the demand for cooling increases every year due to economy and population growth. Based on this scenario, this work aims to develop a numerical model of an adsorption chiller driven with solar energy, which can be used to optimize the cooling system operation of the building where the device is situated and compare it with the current cooling methods in use. The numerical study here presented was created using Matlab/Simulink™, it is based on a lumped parameter model that relies on physical properties and represents a cooling system using a pair of silica gel-water in a two-bed chiller. In this study, the authors proposed a simplified version of the system and the numerical model, which aims to reduce the simulation time and provide faster results. Besides the temperatures in the system, which range from 52 °C to 72 °C in the hot cycle and 12 °C to 23 °C in the chilled water cycle, the results also include the variation of water uptake in the two adsorbent beds. In general, the simulated temperature, cooling and heating power and coefficient of performance (COP) are in fair agreement with the literature data, nevertheless, the final results show that improvements still have to be performed.

scholarly journals Parametric assessment of a building active façade by means of a combined metallic sandwich panel with an unglazed solar collector

2019 ◽  
Vol 282 ◽  
pp. 02046
Author(s):  
Peru Elguezabal ◽  
Alex Lopez ◽  
Jesús María Blanco ◽  
José Antonio Chica
Keyword(s):  
Solar Collector ◽  
Fossil Fuels ◽  
Meteorological Parameters ◽  
Poor Performance ◽  
Solar Thermal ◽  
Solar Irradiation ◽  
Inlet Temperature ◽  
Solar Thermal Energy ◽  
Use Stage ◽  
Thermal Difference

The building sector has a poor performance in terms of energy efficiency and is looking for alternatives to reduce the use of fossil fuels on building use stage. Renewables are unlimited and solar thermal energy is a technology with a demonstrated potential. The façade is a key element able to harness renewable energy coming from the sun becoming in an Active Solar Thermal Façade (ASTF). The main purpose of this study is the development of a parametric study using a numerical model to analyze the behavior of an unglazed solar collector. Thus, evaluating different design and meteorological parameters to show their influence on the heat transfer and the efficiency. The study shows that solar irradiation and mass flow are the most influential on thermal difference. However, for the efficiency ambient temperature and inlet temperature both are the most influencing ones. In brief, a set of parameters have a significant influence on the behavior of the ASTF that are fully governed by environmental conditions. Nevertheless, there are some other parameters that can be controlled during the operation. The challenge is to make a continuous configuration of this adaptable values depending on the external situation to achieve a higher performance for the ASTF.

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