This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (±10% or less) about the sample average with only few outliers. The thermal conductivity of the nanofluids was found to increase with particle concentration and aspect ratio, as expected from classical theory. There are (small) systematic differences in the absolute values of the nanofluid thermal conductivity among the various experimental approaches; however, such differences tend to disappear when the data are normalized to the measured thermal conductivity of the basefluid. The effective medium theory developed for dispersed particles by Maxwell in 1881 and recently generalized by Nan et al. [J. Appl. Phys. 81, 6692 (1997)], was found to be in good agreement with the experimental data, suggesting that no anomalous enhancement of thermal conductivity was achieved in the nanofluids tested in this exercise.

A Benchmark Study on the Thermal Conductivity of Nanofluids

The purpose of this paper is to provide a source of information on thermal energy use in buildings, its drivers, and their past, present and future trends on a global and regional basis. Energy use in buildings forms a large part of global and regional energy demand. The importance of heating and cooling in total building energy use is very diverse with this share varying between 18% and 73%. Biomass is still far the dominant fuel when a global picture is considered; the role of electricity is substantially growing, and the direct use of coal is disappearing from this sector, largely replaced by electricity and natural gas in the most developed regions. This paper identifies the different drivers of heating and cooling energy demand, and decomposes this energy demand into key drivers based on a Kaya identity approach: number of households, persons per household, floor space per capita and specific energy consumption for residential heating and cooling; and GDP, floor space per GDP, and specific energy consumption for commercial buildings. This paper also reviews the trends in the development of these drivers for the present, future – and for which data were available, for the past – in 11 world regions as well as globally. Results show that in a business-as-usual scenario, total residential heating and cooling energy use is expected to more or less stagnate, or slightly decrease, in the developed parts of the world. In contrast, commercial heating and cooling energy use will grow in each world region. Finally, the results show that per capita total final residential building energy use has been stagnating in the vast majority of world regions for the past three decades, despite the very significant increases in energy service levels in each of these regions.

Heating and cooling energy trends and drivers in buildings

The energy security and supplies of energy are the key components for progressing countries. Renewable energy resources are rapidly being recognized as clean sources of energy to withstand damages to environment and to avoid future crisis. In this study, energy consumption and energy demands in the progressing Middle East countries are reviewed. First, the growth of energy consumption of the region through recent years is presented which show the rapidly growing energy demand in the Middle East countries. Second, by using RETScreen software data, the potential of the main renewable energies of solar and wind resources are evaluated. Results showed that the Middle East region have a very good potential for using renewable energies. Results are presented as GIS maps of wind speed, wind power density and solar radiation intensity. With using the GIS maps, the great locations for utilizing solar or wind energies are identified. The presented GIS maps may facilitate development of hybrid solar and wind systems within the Middle East region.

Energy demands and renewable energy resources in the Middle East

A review on solar-powered cooling and air-conditioning systems for building applications

https://www.comune.catania.it/amministrazione-trasparente/informazioni-ambientali/data/catania-air-quality-analysis-2010-2011.pdf

Air quality data for Catania: analysis and investigation case study: 2010-2011

The Kingdom of Saudi Arabia (KSA) is considered one of the countries with the highest consumption of electric energy per capita. Moreover, during the period of 2007–2017, the consumption rate increased from 6.9 MWh to 9.6 MWh. On the other hand, the share of residential electricity consumption in the KSA constitutes the biggest portion of the total electric consumption, which was about 48% in 2017. The objectives of this work were to analyze the exergy and assess the economic and environmental impacts of energy consumption in the residential sector of the Qassim region to determine potential areas for energy rationalization. The consumption patterns of 100 surveyed dwellings were analyzed to establish energy consumption indicators and conduct exergy analysis. The performances of different consuming domestic items were also examined, and energy efficiency measures are proposed. The average yearly consumption per dwelling was determined, and the total energy and exergy efficiencies are 145% and 11.38%, respectively. The average shares of lighting, domestic appliances, water heaters, and air conditioning from the total yearly energy consumption were determined.

Exergy and Economic Analysis of Energy Consumption in the Residential Sector of the Qassim Region in the Kingdom of Saudi Arabia

Conventional energy consumption in refrigeration is one of the important reasons in global warming. Solar cooling systems are becoming more compact, having lower costs, and are potential alternative technologies, especially in hot and sunny climates. The adsorption, absorption, and dissociative evaporative cooling (DEC) are the technologies used for sorption machines, which are discussed in this review paper. Various multi-criteria performance indicators appearing in the previous studies are discussed, followed by evaluating the benefits and drawbacks of distinguishing sorption solar thermal cooling systems. Market research is conducted to prove the capacity of these technologies. The review shows that compared to other technologies, the solar absorption system is more efficient, so it is very commonly used for cooling applications in various locations. An important topic was also presented using phase change materials and nanofluids in solar sorption systems, that need more research. It is noted from this that most solar cooling systems are hybrid in terms of source and there are multiple applications (cooling - heating and electricity generation). The software packages to study these systems are introduced. Further research is required on desiccant materials that can be regenerated under lower temperatures that would augment the extent of solar desiccant cooling application.

Thermal solar sorption cooling systems, a review of principle, technology, and applications

Consumption patterns of residential building in Kingdom of Saudi Arabia (KSA) with specific reference to Qassim region are analysed to establish energy consumption indicators including consumption per dwelling, per capita and per unit area. The average shares of lighting, domestic appliances, water heaters and air conditioning out of total yearly consumption are determined to be 8.5%, 14.7%, 10.3% and 66.5%, respectively. Parametric analysis shows that residential energy consumption is insignificantly influenced by the type of building except that villas have somewhat higher consumption during the hot summer season. However, residential energy consumption is considerably affected by occupant behaviour, meteorological conditions, as well as the technical conditions of both building envelopes and air conditions setting temperature point. Energy efficiency measures are also discussed, and opportunities for energy saving are proposed. Potential energy savings up to 43% in air conditioning cooling load could be achieved by applying the KSA standard of envelope insulation. Total residential consumption savings of 3% could also be achieved by using efficient lighting and savings of 11.1% by adjusting the temperature setting point of air conditioners to 24 °C instead of 22 °C.

Analysis of energy consumption pattern in Saudi Arabia’s residential buildings with specific reference to Qassim region

Lately, with the growth in energy consumption worldwide to support global efforts to improve the climate, developing nations have to take significant measures. Kingdom of Saudi Arabia (KSA) impleme...

Evaluating the potential energy savings of residential buildings and utilizing solar energy in the middle region of Saudi Arabia – Case study:

Global warming has risen as a primary global concern. It has stimulated interest in the development of the renewable energy (RE) system. Studies demonstrated that the regions of Gulf Corporation Co...

Radwan A. Almasri

Papers

Exergy and Economic Analysis of Energy Consumption in the Residential Sector of the Qassim Region in the Kingdom of Saudi Arabia

Thermal solar sorption cooling systems, a review of principle, technology, and applications

Analysis of energy consumption pattern in Saudi Arabia’s residential buildings with specific reference to Qassim region

Evaluating the potential energy savings of residential buildings and utilizing solar energy in the middle region of Saudi Arabia – Case study:

A recent review of energy efficiency and renewable energy in the Gulf Cooperation Council (GCC) region