This paper provides an updated literature review about greenhouse systems and helps to identify the most preferable characteristics of a greenhouse for diverse climates and operating conditions. Data ...on appropriate properties of the covering materials and comparisons of several cladding materials were extensively discussed. The selection process of the greenhouse shape and orientation for different climates is presented, and comparisons between several shapes and orientations are made. This paper also examines the existing thermal models and simulation tools used to optimize the thermal operating conditions of the greenhouse. Furthermore, many recent studies are presented where greenhouses are combined with several systems to provide a favorable microclimate for crops, under extreme, tropical and subtropical climates. Finally, other applications such as greenhouse dryers and seawater greenhouse desalination are also discussed.
CONFLICT, CLIMATE, AND CELLS Harari, Mariaflavia; La Ferrara, Eliana
The review of economics and statistics,
10/2018, Letnik:
100, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We conduct a disaggregated empirical analysis of civil conflict at the subnational level in Africa over 1997 to 2011 using a new gridded data set. We construct an original measure of ...agriculture-relevant weather shocks exploiting within-year variation in weather and in crop growing season and spatial variation in crop cover. Temporal and spatial spillovers in conflict are addressed through spatial econometric techniques. Negative shocks occurring during the growing season of local crops affect conflict incidence persistently, and local conflict spills over to neighboring cells. We use our estimates to trace the dynamic response to shocks and predict how future warming may affect violence.
This research investigated the first zero energy building (ZEB) in Southeast Asia which was retrofitted from an existing building and incorporated diverse passive and active design strategies for the ...tropical climate. The study disclosed the efficiency improvement through each individual design strategy and also compared the cost-effectiveness of active and passive categories. The most cost effective active strategy was efficient lighting; and the second was efficient air conditioning systems. The most cost effective passive strategy was lighting pies; and the second was lighting controls. Generally, passive strategies might have longer period of payback. It should be noted that the ZEB was a test-bedding project; therefore, the finding on passive design cost-effectiveness should be cautiously interpreted considering the scale of applications. The research suggests that active and passive strategies should be integrated into building design to optimize the energy performance. Particularly, passive design shall be applied in a large scale to have significant energy improvements.
•A new rectangular tube as absorber for the PVT solar collector was developed.•Different types of nanofluids (SiO2, TiO2 and SiC) evaluated.•ηel PVT SiC nanofluid was 13.52% at 1000W/m2 and flow rate ...of 0.17kg/s.•ηcombined PVT SiC nanofluid was 81.73% at 1000W/m2 and flow rate of 0.17kg/s.
The flat plate photovoltaic thermal (PVT) collectors can be classified into the type of working fluids used namely the water based PVT collectors, air based PVT collectors and combination of water/air PVT collectors. However, low thermal conductivity of the working fluids has always been the primary limitation in the development of energy-efficient heat transfer fluids, and higher collector performance. To overcome this limitation, there is a strong motivation to improve the heat transfer of fluids with higher thermal conductivity. This new generation of heat transfer fluids called nanofluids consists of suspended nanoparticles and has higher suspension stability compared to the millimeter or micrometer size nanoparticles. Thus, the heat transfer characteristics will be enhanced by using nanofluids. The PVT collector has been designed, fabricated and tested outdoor under the Malaysia tropical climate conditions. The PVT collector consists of specially designed rectangular tube absorber (stainless steel material, height of 15mm, width of 25mm and thickness of 1mm) attached under the photovoltaic module. The PVT collector was experimentally tested with different types of nanofluids (SiO2, TiO2 and SiC). The results indicated that the PVT collector with SiC nanofluid has the highest combined photovoltaic thermal (PVT) efficiency of 81.73% and PVT electrical efficiency of 13.52% with the best overall energy coefficient (COE) of 0.93 has been achieved at a flow rate of 0.170kg/s and solar irradiance levels of 1000W/m2, followed by PVT-TiO2 nanofluids, PVT-SiO2 nanofluids, and PVT-water respectively.
•We examine decay in engineered wood products and paper from landfills in Australia.•Decay varied for paper depending on paper type and to some extent landfill type.•Climate did not influence levels ...of decay observed for EWPs.•Decay in C&D landfills was lower than for MSW landfills.•Current decay factors for most products investigated overestimate methane emissions.
Large volumes of engineered wood products (EWPs) and paper are routinely placed in landfills in Australia, where they are assumed to decay. However, the extent of decay for EWPs is not well-known. This study reports carbon loss from EWPs and paper buried in landfills in Sydney, Brisbane and Cairns in Australia, located in temperate, subtropical and tropical climates, respectively. The influence of pulp type (mechanical and chemical) and landfill type (municipal solid waste – MSW and construction and demolition – C&D) on decay levels were investigated. Carbon loss for EWPs ranged from 0.6 to 9.0%; though there is some uncertainty in these values due to limitations associated with sourcing appropriate controls. Carbon loss for paper products ranged from 0 to 58.9%. Papers produced from predominantly mechanical pulps generally had lower levels of decay than those produced via chemical or partly chemical processes. Typically, decay levels for paper products were highest for the tropical Cairns landfill, suggesting that climate may be a significant factor to be considered when estimating emissions from paper in landfills. For EWPs, regardless of the landfill type and climate, carbon losses were low, confirming results from previous laboratory studies. Lower carbon losses were observed for EWP and paper excavated from the Sydney C&D landfill, compared with the Sydney MSW landfill, confirming the hypothesis that conditions in C&D landfills are less favourable for decay. These results have implications for greenhouse gas inventory estimations, as carbon losses for EWPs were lower than the commonly assumed values of 23% (US EPA) and 50% (Intergovernmental Panel on Climate Change). For paper types, we suggest that separate decay factors should be used for papers dominated by mechanical pulp and those produced from mostly chemical pulps, and also for papers buried in tropical or more temperate climates.
•Cool colored coating and PCM are two complementary passive cooling strategies.•A PCM cool colored coating system is developed.•The coating reduces cooling energy by 8.5% and is effective yearly in ...tropical Singapore.
Cool colored coating and phase change materials (PCM) are two passive cooling strategies often used separately in many studies and applications. This paper investigated the integration of cool colored coating and PCM for building cooling through experimental and numerical studies. Results showed that cool colored coating and PCM are two complementary passive cooling strategies that could be used concurrently in tropical climate where cool colored coating in the form of paint serves as the “first protection” to reflect solar radiation and a thin layer of PCM forms the “second protection” to absorb the conductive heat that cannot be handled by cool paint. Unlike other climate zones where PCM is only seasonally effective and cool paint is only beneficial during summer, the application of the proposed PCM cool colored coating in building envelope could be effective throughout the entire year with a monthly cooling energy saving ranging from 5 to 12% due to the uniform climatic condition all year round in tropical Singapore.
Latent cooling load accounts for 30% of the total load of air-conditioning, and its proportion is even higher in many tropical and subtropical climates. Traditional vapour-compression ...air-conditioning (VCAC) has a low coefficient of performance (COP) due to the refrigeration dehumidification process, which often makes necessary a great deal of subsequent re-heating. Technologies using conventional desiccants or sorbents for indoor moisture control are even less competitive than VCAC due to their high regeneration temperature, long cycling time and bulky components. Here, we report a novel high temperature cooling system that uses porous metal-organic frameworks (MOFs) as advanced sorbents for humidity control. We directly coat MOFs on the surface of evaporator and condenser. The system has no additional components compared to a traditional VCAC. The evaporator can simultaneously remove both the sensible and latent loads of the incoming air without reducing the temperature below its dew point. The regeneration of wet MOFs is completely driven by the residual heat from the condenser. The MOF-coated heat exchangers can achieve a cooling power density of 82 W·L
. We demonstrate that the system has a high COP, up to 7.9, and can save 36.1% of the energy required, compared to the traditional VCAC system with reheating. The amphiphilic MOFs used in the research have high water uptake, are made of low-cost raw materials and have high hydrothermal stability. They thus have the potential for being scaled up for large-scale applications in air conditioning.
The aim of this study is to investigate the seasonal effect of dust on the degradation of PV modules deployed in two different climate areas, Perth, Western Australia, a temperate climate region and ...Nusa Tenggara Timur (NTT), Indonesia, a tropical climate region. Results revealed that PV performance varied with season. In Perth, the performance of PV modules which was maximal in the beginning of summer decreased significantly at the end of the season. The performance then increased back approaching the initial position at the end of autumn and reached a peak at the end of winter. Similar reduction to the summer’s performance was accounted by the modules at the end of spring. Meanwhile, in NTT, the performance of PV modules was maximal in the beginning of wet season, dropped slightly at the end of the season and decreased significantly at the end of dry season. Degradation of all modules in the two sites was more affected by dust compared to the non-dust related factors. The degradation is important information for future PV design in both areas, especially in NTT which accounted greater values than the typical dust de-rating factors.
•The effect of dust on PVs’ performance varied with season.•Dust more dominant than non-dust related factors to degrade PV module performance.•More intense of cleaning should be applied for PV modules mounted at lower latitude and deployed in a tropical climate area.
The Indian Ocean Dipole (IOD) affects climate and rainfall across the world, and most severely in nations surrounding the Indian Ocean
. The frequency and intensity of positive IOD events increased ...during the twentieth century
and may continue to intensify in a warming world
. However, confidence in predictions of future IOD change is limited by known biases in IOD models
and the lack of information on natural IOD variability before anthropogenic climate change. Here we use precisely dated and highly resolved coral records from the eastern equatorial Indian Ocean, where the signature of IOD variability is strong and unambiguous, to produce a semi-continuous reconstruction of IOD variability that covers five centuries of the last millennium. Our reconstruction demonstrates that extreme positive IOD events were rare before 1960. However, the most extreme event on record (1997) is not unprecedented, because at least one event that was approximately 27 to 42 per cent larger occurred naturally during the seventeenth century. We further show that a persistent, tight coupling existed between the variability of the IOD and the El Niño/Southern Oscillation during the last millennium. Indo-Pacific coupling was characterized by weak interannual variability before approximately 1590, which probably altered teleconnection patterns, and by anomalously strong variability during the seventeenth century, which was associated with societal upheaval in tropical Asia. A tendency towards clustering of positive IOD events is evident in our reconstruction, which-together with the identification of extreme IOD variability and persistent tropical Indo-Pacific climate coupling-may have implications for improving seasonal and decadal predictions and managing the climate risks of future IOD variability.
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