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

2020 ◽  
Author(s):  
Tryfonas 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 has increased the need for renewable energy deployment for covering thermal loads. Towards 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 of separate components testing 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 at a range of 75 °C. The corresponding mean energy efficiency ratio (EER) obtained was 5.8.

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.

Charge optimisation of a solar milk chiller with direct current compressors

2020 ◽  
pp. 095440892096400
Author(s):  
Shaji Sidney ◽  
Rajendran Prabakaran ◽  
Mohan Lal Dhasan
Keyword(s):  
Direct Current ◽  
Coefficient Of Performance ◽  
Ice Formation ◽  
Exergy Destruction ◽  
Hfc 134A ◽  
Refrigerant Circuit ◽  
Maximum Coefficient ◽  
Photo Voltaic ◽  
Solar Powered ◽  
Optimum Charge

In view of promoting the utilization of solar photo-voltaic energy for milk chilling application a custom designed milk chiller with DC compressors was fabricated. Two different DC compressors were used operating with HFC-134a and HC-600a refrigerants to ascertain the performance of HFC and HC refrigerants when used in solar powered application. In view of optimizing the performance of both refrigerants, charge optimization was experimentally carried out for both refrigerant circuits. The optimum charge was obtained based on the maximum coefficient of performance and exergy efficiency. When comparing ice formation and coefficient of performance, the HC-600a refrigerant circuit was lower than that of HFC-134a circuit. It was also observed that the total exergy destruction experienced was maximum in the HFC-134a circuit than that of the HC-600a circuit. The magnitude of exergy destruction was found to be maximum in the compressor and then followed by the condenser, evaporator and finally the capillary for both refrigeration circuits. This study showed an efficient way for using the solar power for operating a milk chiller with DC compressors and with ice bank tank to avoid the dependency on batteries.

scholarly journals Гибридные режимы работы термоэлектрических модулей

2022 ◽  
Vol 56 (1) ◽  
pp. 13
Author(s):  
И.А. Драбкин ◽  
Л.Б. Ершова
Keyword(s):  
Cooling Capacity ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Large Temperature ◽  
Hybrid Mode ◽  
Cooling Mode ◽  
Thermoelectric Coolers ◽  
General Cooling ◽  
Maximum Coefficient

It is suggested that thermoelectric coolers designing should not be limited to the extreme modes of their operation. In some cases, it is convenient to use the so called hybrid modes - a combination of the extreme mode of maximum coefficient of performance for large temperature differences and a general cooling mode for small ones. The proposed hybrid mode makes it possible to control the cooling capacity of the module and not to confine this value to that under the extreme operating conditions, the maximum coefficient of performance in particular.

Optimal Allocation of Heat Exchanger Inventory of a Two-Stage Vapor Compression Cycle for Maximum Coefficient of Performance

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
M. J. Morales ◽  
S. A. Sherif
Keyword(s):  
Heat Exchanger ◽  
High Performance ◽  
Optimal Allocation ◽  
Low Cost ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Two Stage ◽  
Inventory Allocation ◽  
Maximum Coefficient

The purpose of this study is to investigate how the heat exchanger inventory allocation plays a role in maximizing the thermal performance of a two-stage refrigeration system with two evaporators. First, the system is modeled as a Carnot refrigerator and a particular heat transfer parameter is kept constant as the heat exchanger allocation parameter is allowed to vary. The value of the heat exchanger allocation parameter corresponding to the maximum coefficient of performance (COP) is noted. The results are compared to those of a non-Carnot refrigerator with isentropic and nonisentropic compression. It is found that the Carnot refrigerator can be used to predict the value of the heat exchanger allocation parameter where the maximum COP occurs for a non-Carnot refrigerator. In order to improve the accuracy of that prediction, the predicted value of the heat exchanger allocation parameter has to be inputted into the set of equations used for the non-Carnot refrigerator. This study is useful in designing a low-cost, high-performance refrigeration system.

Modeling a Novel Composite Adsorbent Based Adsorption Chiller Driven by Solar Energy

2013 ◽  
Author(s):  
C. Y. Tso ◽  
S. C. Fu ◽  
Christopher Y. H. Chao
Keyword(s):  
Coefficient Of Performance ◽  
Seasonal Effects ◽  
Cooling Power ◽  
Insulation Material ◽  
Composite Adsorbent ◽  
Adsorption Chiller ◽  
Flat Type ◽  
Collector Temperature ◽  
Typical Summer ◽  
Solar Powered

This paper aims to study the performance of a solar-powered adsorption chiller with a novel composite adsorbent material (silica activated carbon/CaCl2) operating during some typical months in Hong Kong. Modeling is established to investigate the cooling performance of this adsorption chiller driven by flat-type solar collectors with three different configurations of glaze: 1) single glazed cover; 2) double glazed cover and 3) transparent insulation material (TIM) cover. The simulation results show that the higher the solar collector temperature is, the better the coefficient of performance (COP) and the specific cooling power (SCP) of the adsorption chiller are. It is suggested to select a double glazed collector with a small value of the lumped capacitance for this adsorption chiller. Seasonal effects are discussed in which the solar COP achieves its highest value during autumn. However, the cooling capacities in spring, summer and autumn are similar. All in all, this newly developed composite material as adsorbent used in the adsorption chiller could achieve a mean solar COP of 0.36 and SCP of 94W/kg on a typical summer day of operation.

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 Design and Transient Analysis of a Natural Gas-Assisted Solar LCPV/T Trigeneration System

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5930
Author(s):  
Yang Liu ◽  
Han Yue ◽  
Na Wang ◽  
Heng Zhang ◽  
Haiping Chen
Keyword(s):  
Natural Gas ◽  
Heat Pump ◽  
High Efficiency ◽  
Coefficient Of Performance ◽  
Cooling Mode ◽  
Energy Supply System ◽  
Simulation Performance ◽  
Temperature Heat ◽  
Maximum Coefficient ◽  
Transient System

This paper proposes a natural gas assisted solar low-concentrating photovoltaic/thermal trigeneration (NG-LCPV/T-TG) system. This novel system simultaneously provides electrical, thermal and cooling energy to the user. The design and dynamic simulation performance of the NG-LCPV/T-TG system is completed using Transient System Simulation (TRNSYS) software. The results show that the system can satisfy the requirements of the cooling and heating load. The proposed system maintains the experimental room temperature at about 25 °C under the cooling mode, at about 20 °C under the heating mode. The electrical and thermal energy produced by the low-concentrating photovoltaic/thermal (LCPV/T) system are 3819 kWh and 18,374 kWh. Meanwhile, the maximum coefficient of performance (COP) of the low temperature heat pump (LHP), high temperature heat pump (HHP) and chiller are 5, 2.2 and 0.6, respectively. This proposed system realizes the coupling of natural gas and solar energy in a building. In summary, this trigeneration system is feasible and it promotes the implementation of building integrated high-efficiency energy supply system.

scholarly journals Absorption and adsorption chillers applied to air conditioning systems

2010 ◽  
Vol 31 (2) ◽  
pp. 77-94 ◽  
Author(s):  
Agnieszka Kuczyńska ◽  
Władysław Szaflik
Keyword(s):  
Heat Source ◽  
Air Conditioning ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Geothermal Heat ◽  
Pump System ◽  
Desorption Process ◽  
Heat Pump System ◽  
Adsorption Chiller ◽  
Air Conditioning Systems

Absorption and adsorption chillers applied to air conditioning systemsThis work presents an application possibility of sorption refrigerators driven by low temperature fluid for air conditioning of buildings. Thermodynamic models were formulated and absorption LiBr-water chiller with 10 kW cooling power as well as adsorption chiller with silica gel bed were investigated. Both of them are using water for desorption process with temperatureTdes= 80 °C. Coefficient of performance (COP) for both cooling cycles was analyzed in the same conditions of the driving heat source, cooling waterTc= 25 °C and temperature in evaporatorTevap= 5 °C. In this study, the computer software EES was used to investigate the performance of absorption heat pump system and its behaviour in configuration with geothermal heat source.

scholarly journals Using adsorption chillers for utilising waste heat from power plants

2019 ◽  
Vol 23 (Suppl. 4) ◽  
pp. 1143-1151 ◽  
Author(s):  
Karol Sztekler ◽  
Wojciech Kalawa ◽  
Sebastian Stefanski ◽  
Jaroslaw Krzywanski ◽  
Karolina Grabowska ◽  
...  
Keyword(s):  
Power Generation ◽  
Energy Efficiency ◽  
Power Plant ◽  
Power Plants ◽  
Waste Heat ◽  
Primary Energy ◽  
Simulation Software ◽  
Coefficient Of Performance ◽  
Low Grade ◽  
Adsorption Chiller

At present, energy efficiency is a very important issue and it is power generation facilities, among others, that have to confront this challenge. The simultaneous production of electricity, heat and cooling, the so-called trigeneration, allows for substantial savings in the chemical energy of fuels. More efficient use of the primary energy contained in fuels translates into tangible earnings for power plants while reductions in the amounts of fuel burned, and of non-renewable resources in particular, certainly have a favorable impact on the natural environment. The main aim of the paper was to investigate the contribution of the use of adsorption chillers to improve the energy efficiency of a conventional power plant through the utilization of combined heat and power waste heat, involving the use of adsorption chillers. An adsorption chiller is an item of industrial equipment that is driven by low grade heat and intended to produce chilled water and desalinated water. Nowadays, adsorption chillers exhibit a low coefficient of performance. This type of plant is designed to increase the efficiency of the primary energy use. This objective as well as the conservation of non-renewable energy resources is becoming an increasingly important aspect of the operation of power generation facilities. As part of their project, the authors have modelled the cycle of a conventional heat power plant integrated with an adsorption chiller-based plant. Multi-variant simulation calculations were performed using IPSEpro simulation software.

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