Technical and economical assessment of energy-saving roof and wall construction in Thailand

This research assessed the economic impact and construction costs of buildings with solar chimneys in Thailand, called bioclimatic houses. A solar chimney uses a combination of air gaps between walls and roof, and effective ventilation to lower the indoor temperature and reduce the need for air conditioning. The study looked at small, medium, and large size houses and studied construction techniques, the materials used, and the time needed to build a residential structure. It also polled owners of bioclimatic houses about their satisfaction. The techniques employed in building bioclimatic houses take slightly longer and cost slightly more than those used in standard construction. However, the study found that bioclimatic houses use approximately 10–20% less electricity for air conditioning require less maintenance and have a payback period of 6–13 years, depending on the size. The lifespan of insulation material used in standard houses is about 20–25 years, while the lifespan of a solar chimney is about 40–50 years. The solar chimney concept can also be applied to standard houses with minimal renovation. The study found that this type of house was suitable for use in Thailand, and with increased consumer awareness, had a high probability for adoption.     

Development of a new solar thermal engine system for circulating water for aeration

This paper presents a numerical study about the performance of a Beta Stirling solar thermal engine system. This system is composed of a solar collector box connected to a regenerator hydraulic system and a transmitting power system. The objective of the system is to offer a new alternative to help solving stagnant water pollution in hot countries like Thailand by circulating water in canals, lakes, ponds etc. for aeration using solar energy.The purpose of this study is to determine the power output and actual heat transfer on the performance of the solar thermal engine. The solar thermal engine is analyzed using a mathematical model based on the first law of thermodynamics for processes with finite speed, with particular attention to the energy balance at the receiver. The result of calculations showed that the regenerator volume and phase angle must be chosen carefully to fulfill the requirement that total fluid mass in the system is constant and to obtain maximum power output throughout the day.     

Feasibility study of desiccant air-conditioning system in Thailand

The objective of this study was to conduct an experimental analysis to investigate the performance and energy saving of the well-known desiccant air-conditioning system in Thailand. The system was composed of a silica gel bed, a split type air-conditioner (1.5 ton refrigeration) installed in a room of volume 76.8 m³, air ducts and a blower. Its design allows us to adjust the percentages of return air, outdoor air and indoor air mixed to the air leaving the desiccant, and desiccant bed thickness as well. Tests were conducted on several days with relatively similar ambient conditions. Under the test conditions used here, a 5 cm bed thickness is recommended with a maximum adsorption rate of 473 g/h. The optimum percentages of air ratios are as follows: 15% outdoor air, 15% return air (mixed together at the desiccant bed inlet) and 70% of indoor air mixed to the dry air leaving the desiccant. The corresponding electricity saving was about 24%. As expected, simple economic analysis indicated that the desiccant air-conditioning is only viable for large cooling capacities and central air-conditioned buildings. The payback period is about 4 yr.     

Critical analysis of Thailand’s past energy policies towards the development of a new energy policy

This research originated from the researchers’ participation in the Thai senate Committee on Energy. It studies energy strategies and guidelines for Thailand’s energy development in line with the country’s potential, its energy resources as well as the needs of the Thai people with the ultimate goal to help bring about sustainable energy development. The research found that continuing dependence on natural gas crisis will pose a major threat with sustainable development of energy. According to its current power development plans, Thailand will likely increase its dependence on natural gas. The country should therefore diversify the use of energy sources since over-dependence on a single fuel will create risks to energy security, especially security of the fuels used in the generation of electricity. It is imperative to increase promotion of measures for energy conservation and energy efficiency, including measures to reduce fuel consumption and switching to renewable energy.     

Inorganic and Organic Compounds of Freshwater Filamentous Cyanobacteria under Normal and Salt Stress Conditions

The main aim of this work was to investigate the effects of salt stress conditions on the inorganic and organic compounds of extracts from six filamentous cyanobacteria： Arthospira platensis, Oscillatoria sp., Oscillatoria salina, Tolypothrix sp., Oscillatoria sp. SWU （Srinakharinwirot University）121 and Tolypothrix sp. SWU213. All cyanobacteria were cultures in BG （blue-green algae）11 medium： pH 7.5 at 35 ℃ for 30 days of sodium chloride in the culture medium presented 0-1.0 M. The cyanobacteria isolates grew well in BGH medium, nevertheless, growth of the majority of isolates was reduced by about 50% in the same medium containing 0.5 M NaCl. The inorganic compounds such as, Na^＋, K^＋, Ca^2＋, Mg^2＋, NH4^＋ and NO3^- were determined. All ions were reduced when NaCI was increased and Na^＋ showed highest amount in the medium followed with Mg^2＋, NH4^＋, NO3^- and Ca^2＋ in all cyanobaeteria. The organic compounds such as, betaine, proline and total lipid were determined under normal and salt stress conditions. We found that all cyanobacteria increased interesting organic compound under salt stress condition at least two folds to compare with normal condition. This is the first finding indicated that freshwater filamentous cyanobacteria could grow under salt stresses by accumulation of some organic compounds as osmoprotectants such as betaine and amino acids, being the reduction related to the amount of inorganies compounds present in cultures.     

Investigation on thermal performance of glazed solar chimney walls

This paper reports investigation on the thermal performance of glazed solar chimney walls (GSCW) under the tropical climatic conditions of Thailand. The GSCW consisted of double glass panes with an air layer and openings located at the bottom (room side glass pane) and at the top (ambient side glass pane). A prototype of GSCW was integrated into the southern wall of a small room of 2.8 m³ volume. Its dimensions were as follows: 0.74 m height, 0.50 m width and 0.10 m air gap. The size of openings was 0.05 × 0.5 m². With a clear glass of 6 mm thickness, velocity field measurement indicated that the induced airflow rate was about 0.13–0.28 m³/s. The temperature difference between room and ambient was less than that with a single layer clear glass window. The reduction of daylight due to the double glass layer is negligible. Comparison between simulated and experimental results showed a reasonable agreement, therefore, the developed numerical model is valid and could be used as a tool for the design of GSCW.     

The association between parental warmth and control in thirteen cultural groups.

The goal of the current study was to investigate potential cross-cultural differences in the covariation between two of the major dimensions of parenting behavior: control and warmth. Participants included 1,421 (51% female) 7- to 10-year-old (M = 8.29, SD = .67 years) children and their mothers and fathers representing 13 cultural groups in nine countries in Africa, Asia, Europe, the Middle East, and North and South America. Children and parents completed questionnaires and interviews regarding mother and father control and warmth. Greater warmth was associated with more control, but this association varied widely between cultural groups. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Design Biogas Production from Mixed Napier Pak Chong I/Food Waste at Thermophilic Temperature by Anaerobic Digestion in Cow Dung and Chicken Dung

AD （anaerobic digestion） is a beneficial and efficient technique for the treatment of agricultural wastes, food wastes and wastes water to produce renewable energy. Solid agricultural are potential renewable energy resoures. Biogas production by co-digestion of mixed Napier Pak Chong I and food waste at thermophilic temperature using anaerobic digestion in cow dung and chicken dung as the seed inoculums were investigated. The total reactor volume of the co-digester reactor was 7.94 m^3, which was equipped with pump, and it was operated continuously for the 20 days as a pilot scale at 50 ℃. The Napier Pak Chong I was cut into 2 mm sections, and the initial VS （volatile solids） was 30%. The initial VS of food waste were 70%. Two pilot-scale digesters filled with Napier Pak Chong I and food waste, which both digesters contained 476 kg of Napier Pak Chong I mixed 305 L of food waste, and 1305 L of water. There were carried out to investigate the optimum C/N （carbon to nitrogen） ratio for effective biogas production. The slurry raw materials provided sufficient buffering capacity to maintain appropriate pH values （between 7.0 and 8.0）. Digester I was designed for 1.98 m^3 of cow dung as the seed inoculum while digester II was designed to establish 1.98 m^3 of chicken dung as the seed inoculum. Gas detector performs analysis gas production. The m^3/day in digester I and 1.86 m^3/day from digester II, resulting in added, respectively. Biogas production in digester I was directly experimental results indicate that total biogas production was 2.19 specific methane yields of 1.26 m^3 CH4/kgVS and 1.07 m^3 CH4/kgVS correlated with temperature.     

Physico‐mechanical properties of natural rubber sheets coated by polyethyleneimine‐functionalized poly(methyl methacrylate) nanoparticles

The surface modification of sulfur‐prevulcanized natural rubber (SPNR) sheets by the polyethyleneimine‐functionalized‐poly(methyl methacrylate) (PMMA/PEI) nanoparticles was successfully performed via a simple dipping method. The percentage of surface coverage (C_s) of the nanoparticles on SPNR sheets was found to be affected by a variation of nanoparticle latex concentrations and immersion times. The adsorption isotherm of PMMA/PEI nanoparticles on SPNR sheets was analyzed and found to fit well to the Freundlich model. After coating, it can be observed that the presence of PMMA/PEI nanoparticles on SPNR surface had no effects over the SPNR mechanical properties e.g., tensile strength, elongation at break, and hardness. On the other hand, the coated SPNR sheets showed a reduction of surface friction coefficients and interfacial adhesion up to 45 and 59%, respectively. Furthermore, PMMA/PEI nanoparticles adsorbed on the SPNR surface was subjected to stretching and wearing conditions, and found to be stable for at least seven stretching and wearing cycles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012