Influence of permeability ratio on wind-driven ventilation and cooling load of mid-rise buildings

2021 ◽  
Vol 70 ◽  
pp. 102894
Author(s):  
Paria Saadatjoo ◽  
Mohammadjavad Mahdavinejad ◽  
Guoqiang Zhang ◽  
Kianoush Vali
Keyword(s):  
Cooling Load ◽  
Permeability Ratio

ANALISIS BEBAN PENDINGINAN PADA COLD STORAGE UNTUK PENYIMPANAN DAGING

2019 ◽  
Vol 7 (1) ◽  
pp. 12-22
Author(s):  
Ratu Mutia Fajarani ◽  
Yopi Handoyo ◽  
Raden Hengki Rahmanto
Keyword(s):  
Experimental Method ◽  
Cold Storage ◽  
Freezing Point ◽  
Cooling Load ◽  
Internal Factors ◽  
External Cooling ◽  
Preservation Method ◽  
Load Calculation ◽  
Selection Of

Cooling is the best preservation method than others because the food that has been cooled will remain fresh and will not experience a change in taste, color and aroma, besides all the activities that cause decay will stop so that the cooled food will last longer. (Hartanto, 1984). With the proper cooling engine planning, it can help with spatial adjustments, adjustments to loading, estimation of the power to be used, and budget plans. That is what is commonly called the cooling load calculation. Calculation of cooling load needs to be carried out before planning. This is necessary because the magnitude of the pending load is very influential on the selection of the cooling engine so that the freezing point for preserving food can be accurate. Pendiginan burden is influenced by external and internal factors. With the experimental method, it is obtained the results of the external cooling load as the external cooling load is 11.6 kW, the inner cooling load is 138.8 kW and the performance work coefficient (COP) is 2.

Experimental and numerical studies of reducing cooling load of lecture hall

2015 ◽  
Vol 89 ◽  
pp. 163-169 ◽  
Author(s):  
M.W. Muhieldeen ◽  
N.M. Adam ◽  
B.H. Salman
Keyword(s):  
Lecture Hall ◽  
Cooling Load ◽  
Numerical Studies

scholarly journals A novel hybrid liquefied natural gas process with absorption refrigeration integrated with molten carbonate fuel cell

2021 ◽  
Author(s):  
Mehdi Mehrpooya ◽  
Parimah Bahramian ◽  
Fathollah Pourfayaz ◽  
Hadi Katooli ◽  
Mostafa Delpisheh
Keyword(s):  
Energy Consumption ◽  
Fuel Cell ◽  
Natural Gas ◽  
Hybrid System ◽  
Liquefied Natural Gas ◽  
Molten Carbonate Fuel Cell ◽  
Cooling Load ◽  
Absorption Refrigeration ◽  
Molten Carbonate ◽  
Carbonate Fuel Cell

Abstract The production of liquefied natural gas (LNG) is a high energy-consuming process. The study of ways to reduce energy consumption and consequently to reduce operational costs is imperative. Toward this purpose, this study proposes a hybrid system adopting a mixed refrigerant for the liquefaction of natural gas that is precooled with an ammonia/water absorption refrigeration (AR) cycle utilizing the exhaust heat of a molten carbonate fuel cell, 700°C and 2.74 bar, coupled with a gas turbine and a bottoming Brayton super-critical carbon dioxide cycle. The inauguration of the ammonia/water AR cycle to the LNG process increases the cooling load of the cycle by 10%, providing a 28.3-MW cooling load duty while having a 0.45 coefficient of performance. Employing the hybrid system reduces energy consumption, attaining 85% overall thermal efficiency, 53% electrical efficiency and 35% fuel cell efficiency. The hybrid system produces 6300 kg.mol.h−1 of LNG and 146.55 MW of electrical power. Thereafter, exergy and sensitivity analyses are implemented and, accordingly, the fuel cell had an 83% share of the exergy destruction and the whole system obtained a 95% exergy efficiency.

scholarly journals How Can Floor Covering Influence Buildings’ Demand Flexibility?

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3658
Author(s):  
Hyeunguk Ahn ◽  
Jingjing Liu ◽  
Donghun Kim ◽  
Rongxin Yin ◽  
Tianzhen Hong ◽  
...  
Keyword(s):  
Demand Response ◽  
Radiant Heat ◽  
Response Strategy ◽  
Sensitivity Analyses ◽  
Thermal Mass ◽  
Cooling Load ◽  
Floor Covering ◽  
Load Shifting ◽  
Concrete Floor ◽  
Floor Surface

Although the thermal mass of floors in buildings has been demonstrated to help shift cooling load, there is still a lack of information about how floor covering can influence the floor’s load shifting capability and buildings’ demand flexibility. To fill this gap, we estimated demand flexibility based on the daily peak cooling load reduction for different floor configurations and regions, using EnergyPlus simulations. As a demand response strategy, we used precooling and global temperature adjustment. The result demonstrated an adverse impact of floor covering on the building’s demand flexibility. Specifically, under the same demand response strategy, the daily peak cooling load reductions were up to 20–34% for a concrete floor whereas they were only 17–29% for a carpet-covered concrete floor. This is because floor covering hinders convective coupling between the concrete floor surface and the zone air and reduces radiative heat transfer between the concrete floor surface and the surrounding environment. In hot climates such as Phoenix, floor covering almost negated the concrete floor’s load shifting capability and yielded low demand flexibility as a wood floor, representing low thermal mass. Sensitivity analyses showed that floor covering’s effects can be more profound with a larger carpet-covered area, a greater temperature adjustment depth, or a higher radiant heat gain. With this effect ignored for a given building, its demand flexibility would be overestimated, which could prevent grid operators from obtaining sufficient demand flexibility to maintain a grid. Our findings also imply that for more efficient grid-interactive buildings, a traditional standard for floor design could be modified with increasing renewable penetration.

scholarly journals Parametric Design Structures in Low Rise Buildings in Relation to the Urban Context in UAE

2021 ◽  
Vol 13 (15) ◽  
pp. 8595
Author(s):  
Lindita Bande ◽  
Abeer Alshamsi ◽  
Anoud Alhefeiti ◽  
Sarah Alderei ◽  
Sebah Shaban ◽  
...  
Keyword(s):  
Heat Stress ◽  
Parametric Design ◽  
Residential Buildings ◽  
Cost Evaluation ◽  
Outdoor Thermal Comfort ◽  
Climate Index ◽  
Cooling Load ◽  
Design Structure ◽  
Al Ain ◽  
The City

The city of Al Ain (Abu Dhabi, UAE) has a mainly low rise residential buildings. Villas as part of a compound or separate units represent the majority of the residential areas in the city. Due to the harsh hot arid climate of Al Ain, the energy demand for the cooling load is quite high. Therefore, it is relevant finding new retrofit strategies that are efficient in reducing the cooling load of the villas. The aim of this study is to analyze one particular strategy (parametric shading structure) in terms of design, construction, cost, energy impact on the selected villa. The main data for this study is taken from the local sources. There are six steps followed in this analysis: case study analysis; climate analysis; parametric structure and PV panels; building energy consumption and outdoor thermal comfort; modelling, simulation, and validation; materials, construction, and cost evaluation. The model of the villa was validated for the full year 2020 based on the electricity bills obtained. After adding the parametric design structure, the reduction after shading is approximately 10%. Meanwhile the UTCI (Universal Thermal Climate Index) dropped from extreme heat stress to strong heat stress (average for the month of March and September). These findings are promising in the retrofit industry due to the advanced calculations used to optimize the parametric design structure.

scholarly journals Modelling the Molecular Permeation through Mixed-Matrix Membranes Incorporating Tubular Fillers

Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 58
Author(s):  
Ali Zamani ◽  
F. Handan Tezel ◽  
Jules Thibault
Keyword(s):  
Aspect Ratio ◽  
Relative Permeability ◽  
Polymer Matrix ◽  
Volume Fraction ◽  
Mixed Matrix Membranes ◽  
Analytical Prediction ◽  
Mixed Matrix ◽  
Permeability Ratio ◽  
Filler Volume Fraction ◽  
Matrix Membranes

Membrane-based processes are considered a promising separation method for many chemical and environmental applications such as pervaporation and gas separation. Numerous polymeric membranes have been used for these processes due to their good transport properties, ease of fabrication, and relatively low fabrication cost per unit membrane area. However, these types of membranes are suffering from the trade-off between permeability and selectivity. Mixed-matrix membranes, comprising a filler phase embedded into a polymer matrix, have emerged in an attempt to partly overcome some of the limitations of conventional polymer and inorganic membranes. Among them, membranes incorporating tubular fillers are new nanomaterials having the potential to transcend Robeson’s upper bound. Aligning nanotubes in the host polymer matrix in the permeation direction could lead to a significant improvement in membrane permeability. However, although much effort has been devoted to experimentally evaluating nanotube mixed-matrix membranes, their modelling is mostly based on early theories for mass transport in composite membranes. In this study, the effective permeability of mixed-matrix membranes with tubular fillers was estimated from the steady-state concentration profile within the membrane, calculated by solving the Fick diffusion equation numerically. Using this approach, the effects of various structural parameters, including the tubular filler volume fraction, orientation, length-to-diameter aspect ratio, and permeability ratio were assessed. Enhanced relative permeability was obtained with vertically aligned nanotubes. The relative permeability increased with the filler-polymer permeability ratio, filler volume fraction, and the length-to-diameter aspect ratio. For water-butanol separation, mixed-matrix membranes using polydimethylsiloxane with nanotubes did not lead to performance enhancement in terms of permeability and selectivity. The results were then compared with analytical prediction models such as the Maxwell, Hamilton-Crosser and Kang-Jones-Nair (KJN) models. Overall, this work presents a useful tool for understanding and designing mixed-matrix membranes with tubular fillers.

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