scholarly journals Numerical approach to solar ejector-compression refrigeration system

2016 ◽  
Vol 20 (3) ◽  
pp. 949-952
Author(s):  
Hui-Fan Zheng ◽  
Shu-Qing Guo ◽  
Yin-Long Chen ◽  
Cong-Min Wang
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Numerical Approach ◽  
Refrigeration System ◽  
Efficiency Ratio ◽  
Evaporator Temperature ◽  
Maximal Energy ◽  
Middle Temperature ◽  
Minimal Power Consumption

A model was established for solar ejector-compression refrigeration system. The influence of generator temperature, middle-temperature, and evaporator temperature on the performance of the refrigerant system was analyzed. An optimal generator temperature is found for maximal energy efficiency ratio and minimal power consumption.

scholarly journals Energy and exergy analysis of vapour compression refrigeration system using selected eco-friendly hydrocarbon refrigerants enhanced with tio2-nanoparticle

2017 ◽  
Vol 6 (4) ◽  
pp. 91 ◽  
Author(s):  
Luke Ajuka ◽  
Moradeyo Odunfa ◽  
Olayinka Ohunakin ◽  
Miracle Oyewola
Keyword(s):  
Power Consumption ◽  
Exergy Analysis ◽  
Capillary Tube ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Exergetic Efficiency ◽  
Evaporator Temperature ◽  
Energy And Exergy ◽  
Nano Lubricant ◽  
Energy And Exergy Analysis

The experimental study investigated the energy and exergy performance of a domestic refrigerator using eco-friendly hydrocarbon refrigerants R600a and LPG (R290/R600a: 50%/50%) at 0, 0.05, 0.15 and 0.3wt % concentrations of 15nm particle size of TiO2 nano-lubricant, and R134a. The effects of evaporator temperature on power consumption, coefficients of performance, exergetic efficiency and efficiency defects in the compressor, condenser, capillary tube and evaporator of the system were examined. The results showed that LPG + TiO2 (0.15wt %) and R600a + TiO2 (0. 15wt %) had the best of performances with an average of 27.6% and 14.3% higher coefficient of Performance, 34.6% and 35.15% lower power consumption, 13.8% and 17.53% higher exergetic efficiency, a total exergetic defect of 45.8% and 64.7% lower compared to R134a. The exergetic defects in the evaporator, compressor, condenser, and capillary tube were 38.27% and 35.5%, 49.19% and 55.56%, 29.7% and 33.7%, 39.1% and 73.8% lower in the system when compared to R134a respectively. Generally, the refrigerants with nano-lubricant mixture gave better results with an appreciable reduction in the exergy defect in the compressor than the pure refrigerants, and LPG + TiO2 (0. 15wt %) gave the best result in the refrigeration system based on energy and exergy analysis.

scholarly journals Improving Energy Efficiency in Supermarkets by Retrofitting Low-E Glass Doors for Open Refrigeration Systems with Digital Semi Hermetic Compressor

2021 ◽  
Vol 82 (1) ◽  
pp. 145-157
Author(s):  
Piyanut Saengsikhiao ◽  
Juntakan Taweekun
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Energy Savings ◽  
Payback Period ◽  
Cooling Load ◽  
Data Logger ◽  
Night Time ◽  
Evaporator Temperature ◽  
Energy Efficiency Improvement ◽  
Hermetic Compressor

This research will be presenting energy efficiency improvement options by retrofitting doors for open refrigeration systems in Central Thailand supermarkets that open during the daytime (06:00 am – 06:00 pm), and are closed during the night-time (00:00 am – 6:00 am). The materials and methods used consisted of 15 open refrigeration cabinets with 82 retrofitted doors supported by 41 frames, with the temperature set at medium. The power consumption was indicated in kW, kWh through a power meter data logger for analysis and summarization. The investment required was €21,694 /store, while the payback period of this research was determined to be at 14 months. The cost of energy savings was found to be within a period of 1.1 years, at the rate of 192,220 kWh/year or €18,503 annually. The retrofitted doors is expected to reduce the cooling load and over-burdening of the compressor. The research found that the most viable solution was to use a digital semi-hermetic compressor that can operate in unload and full load status, that was being controlled by the evaporator temperature (TEV) which was set at -10 degree, the condenser temperature (TCD) set at 38 degrees, and the superheat temperature (TSH) at 10 degrees. In the unload status, the power consumption of the digital semi hermetic compressor will decrease by 50%, which has a significant impact for energy savings and is important for night-time when low cooling load is required whereby the compressor’s multiple start–stop cycles are not required. The investment for a digital semi-hermetic compressor was determined to be €7,800/store, and is able to yield energy savings of up to 26,890 kWh/year, or €2,589 annually, with a payback period of 2.9 years.

scholarly journals Improving Energy Efficiency in the Supermarket by Retrofitting Low E Glass Doors for Open Refrigerated

2020 ◽  
Vol 20 (1) ◽  
pp. 11-17
Author(s):  
Piyanut Saengsikhiao ◽  
Juntakan Taweekun ◽  
Kittinan Maliwan ◽  
Somchai Sae-ung ◽  
Thanansak Theppaya
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Customer Behavior ◽  
Cooling Load ◽  
Refrigeration System ◽  
Data Logger ◽  
Night Time ◽  
Medium Temperature ◽  
Central Thailand ◽  
Consumption Saving

This research presents the improving energy efficiency by retrofitting doors for open refrigerated in central Thailand supermarkets that open in the daytime (06.00 am - 6:00 pm) and close in night-time (00.00 am – 6:00 am). The Materials and Methods were open refrigerated 15 cabinet and retrofitting doors for open refrigerated that 41 frames, 82 doors in medium temperature refrigeration system and measure power consumption kW, kWh by power meter data logger for analysis and summarize. The power consumption saving average per 7 days for retrofitting doors was 576 kWh/day, 39.67% that daytime 418 kWh/day, 41.93%, and night-time 116 kWh/day, 33.24%. Besides, the energy of day time more than night time because 1) The time of opening store is longer than closing store 2) In the night time, the refrigerated will close by plastic curtain 3) The request cooling load of day time is longer than day time 4) The sale area/ambient temperature of night time more than day time but the humidity was contrasted. Before retrofitting doors, the maximum and minimum of power consumption was 83.25 kw/hour and 44.73 kw/hour, respectively. Also, the power consumption swing at 38.52 kw/hour, 46.72%, and the maximum and minimum of power consumption after retrofitting doors was 33.15 kw/hour and 30.19 kw/hour, respectively. The power consumption swing at 2.96 kw/hour, 8.93%. In addition, the power consumption swing will after be retrofitting doors will less than before retrofitting doors by 1) The average cooling load will be the same as bolt conditions 2) The request cooling load of doors refrigerated will less than by product load, the swing of sale area temperature and humidity, customer behavior that effect power condition will have the low running operation. This research's investment was 21,694 €, while the payback period of this research was 14 months. Besides, within 1.1 years, that energy saving was 16,020 kWh/Month or 1,542 €/Month, 16,020 kWh/month or 192,220 kWh/Year or 18,503 €/Year.

scholarly journals Energy Assessment of Sorghum Cultivation in Southern Ukraine

Agriculture ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 695
Author(s):  
Oleg Bazaluk ◽  
Valerii Havrysh ◽  
Mykhailo Fedorchuk ◽  
Vitalii Nitsenko
Keyword(s):  
Energy Efficiency ◽  
Total Energy ◽  
Climate Changes ◽  
Field Experiments ◽  
Renewable Energy Sources ◽  
Grain Sorghum ◽  
Mineral Fertilizers ◽  
Efficiency Ratio ◽  
Energy Inputs ◽  
Southern Ukraine

Global climate changes and fossil fuel reserve depletion are drivers for the search for environmentally friendly renewable energy sources. In Europe, biomass represents the main alternative to fossil fuels. Among energy crops, sorghum is a promising crop for arid regions. The biomass yield and energy efficiency of sorghum (both silage and grain) were studied based on field experiments conducted in Southern Ukraine. The following climate changes were identified: an increase in temperature and a decrease in precipitation. The total energy inputs for sweet sorghum were estimated at 11.256 GJ/ha. The main contributors to the energy inputs are mineral fertilizers (56.99%). The experiment showed that a yield of 40.6 t/ha could be achieved with annual precipitation of 350 mm. The energy efficiency ratio was determined to be 11.18. The total energy inputs for grain sorghum was 16.081 GJ/ha. Its yield (grain) varied from 1.92 to 7.05 t/ha. The energy efficiency ratio of grain sorghum ranged from 2.8 to 16.7.

scholarly journals Power and Performance Evaluation of Memory-Intensive Applications

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4089
Author(s):  
Kaiqiang Zhang ◽  
Dongyang Ou ◽  
Congfeng Jiang ◽  
Yeliang Qiu ◽  
Longchuan Yan
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Power Consumption ◽  
Job Scheduling ◽  
Memory System ◽  
Processor Core ◽  
Memory Efficiency ◽  
And Performance ◽  
Reasonable Use ◽  
Server System

In terms of power and energy consumption, DRAMs play a key role in a modern server system as well as processors. Although power-aware scheduling is based on the proportion of energy between DRAM and other components, when running memory-intensive applications, the energy consumption of the whole server system will be significantly affected by the non-energy proportion of DRAM. Furthermore, modern servers usually use NUMA architecture to replace the original SMP architecture to increase its memory bandwidth. It is of great significance to study the energy efficiency of these two different memory architectures. Therefore, in order to explore the power consumption characteristics of servers under memory-intensive workload, this paper evaluates the power consumption and performance of memory-intensive applications in different generations of real rack servers. Through analysis, we find that: (1) Workload intensity and concurrent execution threads affects server power consumption, but a fully utilized memory system may not necessarily bring good energy efficiency indicators. (2) Even if the memory system is not fully utilized, the memory capacity of each processor core has a significant impact on application performance and server power consumption. (3) When running memory-intensive applications, memory utilization is not always a good indicator of server power consumption. (4) The reasonable use of the NUMA architecture will improve the memory energy efficiency significantly. The experimental results show that reasonable use of NUMA architecture can improve memory efficiency by 16% compared with SMP architecture, while unreasonable use of NUMA architecture reduces memory efficiency by 13%. The findings we present in this paper provide useful insights and guidance for system designers and data center operators to help them in energy-efficiency-aware job scheduling and energy conservation.

A Novel Window Type Air-Conditioner with Energy Recovering

2011 ◽  
Vol 250-253 ◽  
pp. 3021-3024
Author(s):  
Qing Hai Luo ◽  
Peng Fei Zhang ◽  
Xiu Fei Yang ◽  
Jun Zou
Keyword(s):  
Energy Efficiency ◽  
Heat Exchanger ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
The Other ◽  
The Novel ◽  
Air Conditioner ◽  
Efficiency Ratio ◽  
Additional Heat ◽  
Experimental Prototype

A novel window type air-conditioner with energy recovering was experimented. The experimental prototype can make fresh air exchange heat with exhaust air in an additional heat exchanger, which consist no additional moving parts. The EER (energy efficiency ratio) of the experimental air-conditioner (EAC) is increased by 17.4~37.3% than that of the original ordinary window type air-conditioner (OAC). On the other hand, the fresh air proportion of the EAC is increased by 20% or so than that of the OAC, so indoor air quality can be greatly improved via the EAC; however the indoor noise of the EAC is increased by 3.2 dB or so. The novel experimental prototype is of great significance for energy efficiency.

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