Ethyl alcohol distillation in a basin solar still

Prediction of alcohol distillation in a solar still with a horizontal evaporating surface and an inclined condensing surface was carried out, based on the model modified by Spalding [Convective Mass Transfer. Edward Arnold, 1963] and Kiatsiriroat et al. [Energy, 1986, 11, 881–886]. With the temperatures measured at the evaporating and condensing surfaces, including the concentration of alcohol in the liquid at the evaporating surface, the mass fluxes of concentrated ethanol, pure alcohol and water distillate yielded from the unit could be estimated. The predicted results agreed well with those of the experiments.     

Performance improvement of the combined cycle power plant by intake air cooling using an absorption chiller

This paper studies how to improve the capacity of the combined cycle (CC) power plant which has been operated for 8 years. The most popular way is to lower intake air temperature to around 15 °C (ISO) and 100% RH before entering the air compressor of a gas turbine (GT). Thailand has 3 seasons: winter, summer and rainy season. According to 2003 Bangkok monthly weather data, all year ambient temperature is higher than 15 °C. This research proposes a steam absorption chiller (AC) to cool intake air to the desired temperature level. It could increase the power output of a GT by about 10.6% and the CC power plant by around 6.24% annually. In economic analysis, the payback period will be about 3.81 years, internal rate of return 40%, and net present value 19.44 MUS$.     

Performance estimation of a PV water-pumping system with utilizability function

A procedure using the concept of the utilizability function for estimating the long-term performance of direct-coupled photovoltaic water-pumping systems is presented. A modified utilizability function, based on radiation statistics, is developed, and the monthly-averaged daily amount of water is simply estimated.     

The chilled water storage analysis for a university building cooling system

In this paper, a methodology is presented to determine the optimal chilled water storage (CWS) capacity and corresponding operating strategy for the air conditioning loads for different electricity tariff. Several scenarios were studied for the KMUTNB air conditioning system. It was concluded that the CWS with a chiller of 450 RT (2 units) running continuously, thermal-energy storage of 9413 RT-h and 5175 m³ volume was most suitable. The mechanical chiller (MAC) capacity and peak demand could be decreased by over 2 times and 31.2% respectively. It can move the energy consumption from the on peak to the off peak periods by 35.7%. The economics result showed PB, IRR and NPV are 10 y, 21% and 0.834 MUS$ compared with the existing system.     

HPA immobilized on the functionalized Ti-MCM-41 nanochannels for photocatalytic degradation of ternary azo dye effluents

Solid-state heteropolytungstic acid (HPA) clusters were covalently linked into amino and mercapto functionalized Ti-MCM-41 nanoporous channel by in situ synthesis processes to effectively use as a recyclable photocatalyst for degradation of ternary azo dyes consisting of methyl orange (MeOr), acid orange 10 (AO-10) and acid red 88 (AR88) before and after dying processes. The structure and morphology of as synthesized nanoporous hybrid catalyst (HPA immobilized mercapto and amino functionalized Ti-MCM41) was characterized by means of Fourier transform infrared analysis (FT-IR), Phosphorus-31 Nuclear Magnetic Resonance (³¹P-NMR) analysis, X-ray diffraction (XRD) analysis, N₂ adsorption studies, diffused reflectance studies (DRS) and transmission electron microscope (TEM) measurements. The immobilization of HPA on functionalized Ti-MCM-41 acts as coupled semiconductor with higher specific area and superior active sites for photocatalytic degradation of ternary azo dyes. The hybrid catalyst was found to be very stable and did not lose it activity even after performing three consecutive irradiation experiments with azo dye mixtures; hence it may be reusable for further degradation of dye mixtures.     

Sustainable energy management in urban transport: The public's response of road congestion pricing in Thailand

Fuel consumption of vehicles is one of the most vigorously debated issues in Thailand. Concerns about the effect of emissions from the vehicles and a significant reliance on imported oil provide legitimate reasons for government action to manage fuel consumption. There are several different policy measures available to affect the fuel-efficient vehicles as well as reduce the amount of driving. This paper presents the major policy measure studies namely congestion pricing, etc. In congestion pricing measure, we conducted a survey of 400 samples in Bangkok area. The purpose of the survey was to inform respondents about a policy designed to reduce freeway congestion and to estimate respondent support for this policy. After receiving extensive information about the policy, respondents were polled on whether they would support, i.e., vote for any or all of these options. The results of the congestion fee survey suggest that 22% of commuting motorists in Bangkok will support congestion fees on the freeways of the region. Public acceptance is substantially enhanced by promising to return at least some of the revenues in the form of reductions in other taxes.     

Influence of Heating Envelope on Structural Fire Integrity of Ferrocement Jackets

The structural fire integrity performance of ferrocement jackets was experimentally determined based on its flexural characteristics and the damage after exposure to fire. The main parameter investigated was the heating envelope, consisting of short and long heating durations of 3 and 63 h, where the maximum temperature in both cases was 1060°C. A sandwich-sample configuration was adopted to simulate the actual conditions of exposure to fire. Test results showed that using ferrocement jackets provided a satisfactory solution for fire protection due to improved post-fire strength as compared with that of plain mortar for both heating envelopes. An increase in wire mesh content significantly improved the mechanical properties of ferrocement under normal conditions; however after fire exposure the content of wire mesh was no longer significant regardless of heating duration. It was also found that higher volume fraction of wire mesh resulted in in-plane cracking. Mortar covers had negligible influence on the mechanical properties of ferrocement jacket exposed to fire for both short and long duration. With regard to failure patterns, it was found that long duration heating caused more severe skeletal steel-induced crack but less mortar spalling.     

Experimental studies of a new solar water heater system using a solar water pump

The research goal was to develop a new solar water heater system (SWHS) that used a solar water pump instead of an electric pump. The pump was powered by the steam produced from a flat plate collector. Therefore, heat could be transferred downward from the collector to a hot water storage tank. The designed system consisted of four panels of flat plate solar collectors, an overhead tank installed at an upper level and a large water storage tank with a heat exchanger at a lower level. Discharge heads of 1, 1.5 and 2 m were tested. The pump could operate at the collector temperature of about 70–90 °C and vapor gage pressure of 7–14 kPa. It was found that water circulation within the SWHS ranged between 12 and 59 l/d depending on the incident solar intensity and system discharge head. The average daily pump efficiency was about 0.0014–0.0019%. Moreover, the SWHS could have a daily thermal efficiency of about 7–13%, whereas a conventional system had 30–60% efficiency. The present system was economically comparable to a conventional one.     

Pyreno-chalcone dendrimers as an additive in the redox couple of dye-sensitized solar cells

Novel pyreno-chalcone dendrimers 1, 2, and 3 were synthesized and their ability to act as an additive in the redox couple (I⁻/I₃ ⁻) of dye-sensitized nanocrystalline TiO₂ solar cell has been tested. The redox couple doped with pyreno-chalcone dendrimer 3 gave a short circuit photocurrent density (J _sc) of 7.40 mA/cm², open circuit voltage (V _oc) of 820 mV, and a fill factor of 0.51, corresponding to an overall conversion efficiency (η) of 7.89% under 40 mW/cm² irradiation.     

Prediction of later-age compressive strength of normal concrete based on the accelerated strength of concrete cured with microwave energy

Microwave energy can accelerate the hydration of cement, resulting in rapid strength development of concrete in an early period. In this paper, prediction of later-age compressive strength of normal concrete, made with rapid-hardening and ordinary Portland cement, based on the accelerated strength of concrete cured with microwave energy was investigated. To accelerate curing properly, the optimal microwave curing process for concrete was first determined and then was applied to concrete. The possible early ages for the strength prediction were found to be at 3.5 and 5.5 h for concrete made with rapid-hardening and ordinary Portland cement, respectively. For each cement type, a formula for the strength prediction was derived from the relationship between accelerated early-age strength of concrete cured with microwave energy and later-age strength of normally cured concrete. Predictions of strength at 7 days for concrete made with rapid-hardening Portland cement and 28 days of concrete made with ordinary Portland cement were within 15% agreement with actual test results.