30 research outputs found
Advance Glazing System – Energy Efficiency Approach for Buildings a Review
No full textAbstractEnergy conservation and energy management has become a matter of concern since last few decades. Window and glazing plays an important role in building energy management. In this regard, glazing technology has gone through rapid evolution. Numerous research and development in glazing fabrication techniques have led to a wider range of design options. Visual transmittance of the glazing unit is important as it determines the amount of daylight through the glazing unit. So, the desired criteria of a glazing system from energy savings point of view is that it should possess higher transmittance in visible spectrum and lower transmittance in infrared region. To check the performance and durability of the glazing systems, thorough research works has been carried out under different conditions. In this paper, an overview of different types of glazing units and their performance has been discussed. A comparison regarding thermal properties of different types of glazing units is also carried out
Performance Evaluation of a Guarded Hot Box U-value Measurement Facility under Different Software based Temperature Control Strategies
No full textAbstractEnergy conservation and energy management can be achieved in buildings by reducing the load on the HVAC systems used in the buildings. This is possible by reducing the magnitude of heat flow through the building materials and components such as the windows, ceilings, floors, walls, etc. The thermal performance of a material can be evaluated by measuring its overall heat transfer coefficient or the U-value. The U-value of a material can be measured using the Guarded Hot Box method. The setup comprises of three parts – the metering box, the guard box and the cold box. In this method a constant heat flow needs to be maintained through the test specimen from the metering box to the cold box. Thus it is important to control temperatures in all the three parts accurately. In the present work the temperatures of the metering box and the guard box have been controlled using three different software based temperature control strategies. In the first two strategies on-off control was implemented while in the third strategy proportional control was implemented. From the experimental data it was found that similar performances were obtained in the first two test cases where the temperatures could be controlled satisfactorily. Whereas, in the third case steady state offset was obtained while controlling the metering box temperature and the guard box temperature showed fluctuations
Study on the Effect of Tilt on the Variation of Aperture Area Shading in a Linear Fresnel Reflector Field for Two Different Configurations
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Effect of fenestration geometrical factors on building energy consumption and performance evaluation of a new external solar shading device in warm and humid climatic condition
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Reuse of fly ash and bottom ash in mortars with improved thermal conductivity performance for buildings
No full textAn approach towards effective utilization of fly ash and bottom ash in the construction of energy efficient buildings has been presented in this paper. Two masonry mortar grades MM3 and MM5 were considered for trial mix. Portland pozzolana cement with substitution of sand by fly ash and bottom ash separately in different substitution ratios (SR) were adopted for preparation of test samples. Fly ash and bottom ash with lime dust and marble dust combinations were also tested as sand free mortars. 28 days compressive strength, apparent porosity, bulk density and thermal conductivity parameters were evaluated for all such samples. By analysing the test results, it was observed that all the SR combinations satisfied the minimum masonry mortar grade MM0.7, as per IS 2250. Both the MM3 and MM5 grade mortars could be produced at 60% SR by fly ash, and corresponding reductions in thermal conductivity values were 69%, and 54% respectively, while compared with conventional mortar. Sand less mortar for both the grades resulted around 57% reductions in corresponding thermal conductivity values. Overall heat transfer co-efficient (U-value) for both side plastered and rendered brick masonry wall panel was found to be reduced by 15.58%, while comparison made between conventional mix of MM5 grade and corresponding 50% fly ash substituted mix. Thus such ash blended mortar mix appears to be advantageous in building envelop application for lowering the overall cooling/heating demand of building, besides utilizing the coal ash up to largest extent and saving natural mineral sand from depletion
Automatic Tuning of Wind Tubrine controller
No full textThe energy demand in current times has increased greatly in last few years. This increasing demand calls for a sustainable and clean energy resource that would reduce the load on non-renewable resources. Wind energy is a renewable resource which is harnessed by mankind from an ancient era. So as to meet this increasing energy demands, innovation in the field of wind energy is required.A wind turbine generates electricity but achieving optimal power is a difficult task. In this case, the optimal power is defined as maximum power produced but at the constraints that the fatigue loading of the wind turbine structure should be as minimum as possible. Also, the wind turbine parameters such as rotor speed and pitch activity should be in a safe operational region. The problem in controlling wind turbines is that they work in a highly uncertain environment where managing so many factors at the same time are difficult. Optimal control of wind turbine has helped in achieving maximum power with-in safe working limits. Due to high uncertainty in the operating conditions of a wind turbine, it is quite a daunting task to find optimal gains for a wind turbine controller.This thesis focuses on achieving optimal gain parameters for wind turbine controller by using an algorithm from machine learning community. In this thesis the problem is formulated as a supervised learning problem where input-output mapping has to be predicted. For this purpose, GPRT is used. The reason behind using GPRT is it takes fewer number of measurements to give good prediction compared to others. The property of GPRT where it deals with uncertain and non linear data with ease, making it a good choice for predicting wind turbine controller gains.The second part of this thesis contains optimisation of the surrogate model achieved by performing regression. The optimisation is done by Monte Carlo Maximum distribution and improved results were generated by applying sequential sampling to this algorithm. This helps us to get a likelihood of optimal gains where the wind turbine gives out rated power with minimal fatigue loads, pitch activity and least deviation of rotor speed from rated.The results obtained from the likelihood was tested for different operational wind speed and also tested for Extreme Operating Gusts as part of disturbance rejection and compared to current parameter used.The comparison shows considerable improvement in the fatigue loads and pitch activity with having improvement in power production. In second case study, more parameters were predicted and optimised using the same algorithm so that the potential of this algorithm can be estimated. This was also performed successfully which proves that this technique can successfully be used to solve higher dimensional problems of wind turbine control.Mechanical Engineering | Systems and Contro
