scholarly journals Space-earth coupling with relation to earths thermal capacity: A case study for Nsukka Region, Nigeria

2022 ◽  
Vol 17 (1) ◽  
pp. 1-9
Author(s):  
J. A. Yakubu ◽  
U. A. Onyeodi ◽  
L. O. Daniyan ◽  
A. Shuaibu ◽  
U. J. Abangwu
Keyword(s):  
Thermal Capacity

scholarly journals Feasibility Analysis and Performance Evaluation and Optimization of a DXSAHP Water Heater Based on the Thermal Capacity of the System: A Case Study

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3883
Author(s):  
Jorge E. De León-Ruiz ◽  
Ignacio Carvajal-Mariscal ◽  
Antonin Ponsich
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Pump ◽  
Thermal Capacity ◽  
Hot Water ◽  
Outlet Temperature ◽  
Solar Collectors ◽  
Pump System ◽  
Heat Pump System

The present work conducts an evaluation of the feasibility and the overall performance and consequent optimization of a direct expansion solar assisted heat pump (DXSAHP) employed for domestic water heating. For the study conducted R134a, R404A, R407C and R410A working fluids were evaluated as well as the use of four, six and eight flat-plate solar collectors and a worktime ranging from 1 to 6 h. The case study is based in Mexico City with a 300 L container and a hot water outlet temperature of 51 °C. The paper introduces a new evaluation criterion based on the thermal capacity and all the evaluations conducted throughout this research revolve around this performance metric. The results show that, the system would require at least 4 h of operation to achieve the outlet temperature. Additionally, it was found that the R410A refrigerant has the best heat transfer properties; with an average condensation heat rate of 6.31 kW, followed by the R407C with 5.72 kW, the R404A with 5.42 kW and the R134a with 5.18 kW. Diversely, the R134a refrigerant requires 0.402 kW of compression work, 62% less than the R410A, which requires 1.06 kW. Consequently, R134a delivers the highest COP, which ranges from 7 to 14, followed by the R407C and R404A refrigerants, which present a similar behaviour between them, with COP ranging from 5 to 9 and 4 to 8, respectively, and finally the R410A, achieving the lowest COP, ranging from 3.5 to 6.5. Moreover, it was found that the R134a presents a higher dispersion regarding the energy exchange rate, which reveals that it is the fluid most susceptible to external factors, such as the weather. Contrarily, the remaining refrigerants present a more consistent performance. Finally, the optimization revealed that the R407C refrigerant is the most suitable given that it requires 20% less compression work than the R404A. This provides the heat pump system with a steadier behaviour, a COP ranging from 7 to 8, 30% higher than R410A, a worktime decrease of 1.5 h and heat transfer area of 5.5 flat-plate solar collectors, equivalent to a 31% reduction, both compared to R134a.

Thermal Behavior of Soils Under Tidal Effect: A Case Study in Guayaquil, Ecuador

2018 ◽  
Author(s):  
Daniel Moreira ◽  
José Macías ◽  
Ruben Hidalgo-León ◽  
Guillermo Soriano
Keyword(s):  
Thermal Behavior ◽  
Geometric Mean ◽  
Thermal Response ◽  
Thermal Capacity ◽  
Tidal Effect ◽  
Horizontal Distance ◽  
Groundwater Level Fluctuations ◽  
Porosity And Permeability

This research analyzes the tidal effect in the thermal properties of the ground for a case study in Guayaquil, Ecuador. A thermal response test (TRT) performed near the shore of the Guayas river presented periodic fluctuations in the thermal behavior concurrent with the tide cycle. First, an analytical solution for tide-induced water table fluctuations was used for the determination of the phreatic level for the days of the test. The analytical model accounted for the horizontal distance from the shore, the ground porosity, and permeability. Afterward, a geometric mean model was used to predict the thermal conductivity of soil considering the groundwater level fluctuations. Finally, a correlation between the effective thermal capacity of the ground and the phreatic level in the soil was found.

scholarly journals Utilization of Excess Production of Waste-Fired CHP Plants for District Cooling Supply, an Effective Solution for a Serious Challenge

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3319
Author(s):  
Mika Fabricius ◽  
Daniel Øland Tarp ◽  
Thomas Wehl Rasmussen ◽  
Ahmad Arabkoohsar
Keyword(s):  
Peak Load ◽  
District Heating ◽  
Waste Incineration ◽  
Thermal Capacity ◽  
Excess Production ◽  
Hourly Data ◽  
Great Pressure ◽  
Heating Load ◽  
The Cost

District heating-connected waste incineration plants face a serious operating challenge during the warmer months of the year when the heating load is quite low. The challenge is the difficulty of managing the extra municipal solid waste to be disposed of, exposing great pressure and cost on the plant. Conventionally, the solution is either burning the surplus waste and providing the extra cooling required for the condenser with a summer chiller and paying the tax of the total heat generation of the plant, or paying other industries to burn the waste for their specific applications. Both of these solutions are, however, costly. In this study, to address this challenge the utilization of the extra available resources of waste incineration plants for district cooling supply is proposed. Then, the proposed solution is analyzed from the thermodynamic and economic points of view. The feasibility of the proposal is investigated for a real waste incineration plant in Denmark and its 50 neighboring office/service buildings as the case study. The simulations are done based on real hourly data of the plant and economic parameters. The results show that for the case study for a plant with a thermal capacity of 73 MW, a district cooling with a peak load of over 20 MW could be perfectly supplied. The payback period of the proposed solution, including the cost of piping, absorption chiller, etc., can be as short as five years.

scholarly journals Assessing the thermal performance of a conventional architecture in a dry warm climate

2021 ◽  
Vol 3 (2) ◽  
pp. 173-182
Author(s):  
Javier Ascanio Villabona ◽  
Jon Terés Zubiaga ◽  
Yesid Alfonso Muñoz Maldonado ◽  
Omar Lengerke Pérez ◽  
Luis Alfonso Del Portillo Valdés
Keyword(s):  
Thermal Behavior ◽  
Thermal Performance ◽  
Construction Materials ◽  
Geographical Location ◽  
Thermal Characterization ◽  
Thermal Capacity ◽  
Weather Data ◽  
Warm Climate ◽  
And Behavior

In this article, we present the results of the evaluation of the thermal performance of a conventional home in a dry warm climate, a case study in Bucaramanga, Colombia. This simulation, evaluation, and analysis make it necessary since currently in the case study area there is no thermal assessment of the dwellings, which are old houses built with resistive and mechanical analyses, but without regard to thermal behavior or thermal housing comfort. This evaluation is done by means of software simulation. Thus, a valid simulation identifies the weather data present in a dry warm climate zone and determines the geographical location and behavior in the solar diagram. Likewise, the thermal characterization of the soil and the construction materials of support and envelopes of the architecture is performed, to establish its thermal transmittance, thermal resistance, and thermal capacity. As a result of the research, the thermal behavior of the house is presented by means of the calculations made that determine the thermal behavior of the envelopes, energy load balancing, and housing thermal comfort based on the ASHRAE 55 standard by Fanger's method. Consequently, with the above, the results of the simulation and a detailed analysis of the recorded data are presented in the document.

scholarly journals A Study of K- Factor Power Transformer Characteristics by Modeling Simulation

2011 ◽  
Vol 1 (5) ◽  
pp. 114-120 ◽  
Author(s):  
O. E. Gouda ◽  
G. M. Amer ◽  
W. A. A. Salem
Keyword(s):  
Power Transformer ◽  
Thermal Capacity ◽  
Power Transformers ◽  
Nonlinear Loads ◽  
Harmonic Current ◽  
Premature Failure ◽  
Modeling Simulation ◽  
Harmonic Currents ◽  
K Factor

Harmonic currents generated by nonlinear loads can cause overheating and premature failure in power transformers. K-factor transformers are specially designed to accommodate harmonic currents and offer protection against overheating caused by harmonics. They minimize harmonic current loss and have an additional thermal capacity of known limits. According to IEEE C57-110, the winding eddy current losses are considered proportional to the harmonic current squared times its harmonic number. K-factor is only an indicative value and the authors' main objective in this paper is to study the effect of harmonics on oil filled transformer and to simulate harmonic behavior using Matlab Simulink. A case study is simulated in order to investigate K-factor values with pumping loads, with and without the use of harmonic filters. Results are compared with measured values.

The Genesis and Internal Dynamics of El Salvador's People's Revolutionary Army, 1970–1976

2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO
Keyword(s):  
Latin America ◽  
El Salvador ◽  
Early Years ◽  
Left Wing ◽  
Internal Dynamics ◽  
Internal Coherence ◽  
The 1960S

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.

Culture and the plasticity of perception

2020 ◽  
Vol 43 ◽  
Author(s):  
Michael Lifshitz ◽  
T. M. Luhrmann
Keyword(s):  
Cultural Context ◽  
Sensory Experience ◽  
Cultural Learning ◽  
The World

Abstract Culture shapes our basic sensory experience of the world. This is particularly striking in the study of religion and psychosis, where we and others have shown that cultural context determines both the structure and content of hallucination-like events. The cultural shaping of hallucinations may provide a rich case-study for linking cultural learning with emerging prediction-based models of perception.

Dual systems for all: Higher-order, role-based relational reasoning as a uniquely derived feature of human cognition

2019 ◽  
Vol 42 ◽  
Author(s):  
Daniel J. Povinelli ◽  
Gabrielle C. Glorioso ◽  
Shannon L. Kuznar ◽  
Mateja Pavlic
Keyword(s):  
Temporal Reasoning ◽  
Higher Order ◽  
Important Case ◽  
Human Cognition ◽  
Relational Reasoning ◽  
Dual Systems ◽  
First Order ◽  
Reasoning System ◽  
Role Based

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.

Sociocultural memory development research drives new directions in gadgetry science

2019 ◽  
Vol 42 ◽  
Author(s):  
Penny Van Bergen ◽  
John Sutton
Keyword(s):  
Episodic Memory ◽  
Autobiographical Memory ◽  
Developmental Psychology ◽  
Cross Cultural ◽  
Memory Development ◽  
Development Research ◽  
Cultural Research ◽  
New Directions ◽  
Cross Cultural Research

Abstract Sociocultural developmental psychology can drive new directions in gadgetry science. We use autobiographical memory, a compound capacity incorporating episodic memory, as a case study. Autobiographical memory emerges late in development, supported by interactions with parents. Intervention research highlights the causal influence of these interactions, whereas cross-cultural research demonstrates culturally determined diversity. Different patterns of inheritance are discussed.

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