Composite Climate Of New Delhi Research Articles

Evaluation of building energy load of a multipurpose hall and its optimization through spectrally selective fenestration and passive design concepts

Sports complexes and recreational centers are large and long-term investments that provide integrated facilities for training athletes and hosting social-cultural events. Due to their daily functioning, such buildings involve high energy consumption resulting in environmental impacts at both local and global scales. This article investigates the currently available methods for assessing the performance characteristics of a Multipurpose Hall using passive design techniques by modifying the building materials used for the wall envelope and fenestration design. Given that the proposed Multipurpose Hall is located near the composite climate of New Delhi, India, a study of climatic responses together with an energy evaluation of the building provides insight into the important envelope design for enhancing a building's energy efficiency. Several energy simulations were performed using DesignBuilder software to determine the annual lighting, heating, and cooling consumption for wall envelopes, window glazings, and dynamic shading techniques. Additionally, the solar gain of various fenestration designs was investigated, and the most energy-efficient building envelope was selected. The comparison of the baseline envelope with the modified envelope design revealed a notable improvement in energy performance.

Performance Prediction and Assessment of Energy Conservation Potential for a Light Pipe System in Indian Composite Climate of New Delhi

Light pipes are popularly used for transporting outdoor sunlight into deep spaces of the building, and hence, use of artificial lighting could be substantially reduced. Performance prediction of a light pipe is an essential step before its use in buildings, so that energy saving potential of the light pipe could be quantified. This paper deals with experimental validation of three existing semi-empirical models for light pipes with different aspect ratios, installed on a windowless test room, at IIT Delhi, New Delhi. Two new semi-empirical models based on the existing correlations are developed. The new model found to perform better with mean bias error (MBE) and root-mean-squared error (MSE) of 0.076 and 0.01, respectively. The better performing new model is used for the evaluation of hourly internal illuminance by the light pipe in a typical meteorological year (TMY) in New Delhi. From hourly internal illuminance in a typical meteorological year, the energy saving potential and CO2 mitigation potential of light pipe system for the test room are evaluated. Monthly average energy saving potentials of the light pipe-fluorescent tube light system are found to be 50% for continuous dimming control and 38% for three-step on–off control. Results show that the light pipe-fluorescent tube light system, with different lighting controls, could reduce CO2 emissions to 15–50%.

Energy matrices analyses of hybrid photovoltaic thermal (HPVT) water collector with different PV technology

In this paper, an attempt has been made to evaluate and compare the energy matrices of a hybrid photovoltaic thermal (HPVT) water collector under constant collection temperature mode with five different types of PV modules namely c-Si, p-Si, a-Si (thin film), CdTe and CIGS. The analysis is based on overall thermal energy and exergy outputs from HPVT water collector. The temperature dependent electrical efficiency has also been calculated under composite climate of New Delhi, India.It is observed that c-Si PV module is best alternative for production of electrical power. Maximum annual overall thermal energy and exergy is obtained for c-Si PV module. The maximum and minimum EPBT of 1.01 and 0.66years on energy basis is obtained for c-Si and CIGS respectively, whereas on exergy basis maximum EPBT of 5.72years is obtained for a-Si and minimum of 3.44 in obtained for CIGS PV module. EPF and LCCE increase with increasing the life time of the system.

Designing energy efficient commercial buildings—A systems framework

This paper provides a means for improving the effectiveness of energy related decision-making during the design phase of a building. A review of the literature and discussions with experts revealed that several approaches for an Integrated Design Process for energy efficient buildings exist. However, most of these approaches are relatively abstract and philosophical in nature, and do not prescribe procedures that enable energy efficient design. This paper attempts to address this gap by proposing a comprehensive design process titled the ‘Integrated Energy-Efficient Building Design Process’ (IEBDP). This process provides a framework based on systems theory that facilitates the integration of various facets of the energy-efficient alternatives selection process. In addition, the proposed framework seeks to integrate state-of-the-art analysis tools and methods, to aid designers in performing holistic building design. Analytical Hierarchy Process (AHP), a multi-attribute decision-making technique is used to resolve conflicts amongst diverging design goals. The proposed IEBDP framework was then used to design an office building, taken as a case study, in the composite climate of New Delhi, India. It was found that considerable energy savings could be achieved by following the IEBDP process. The benefits of this framework vis-a-vis traditional energy efficient design approaches were evaluated by comparing the design done through the IEBDP process with designs submitted by a group of practicing architects. The various designs were evaluated in terms of strategies adopted, the level of exploration as well as design integration, in order to validate the applicability and use of the IEBDP framework.

Performance evaluation of a hybrid photovoltaic thermal double pass facade for space heating

This paper presents the performance evaluation of a hybrid photovoltaic thermal (Semi transparent PVT) double pass facade for space heating. The thermal model has been developed by using the energy balance equations of the proposed hybrid photovoltaic thermal double pass facade under quasi-steady state condition. Numerical computations have been carried out for the composite climate of New Delhi, India. An analysis has been carried out to calculate annual energy and exergy gain for the hybrid photovoltaic thermal double pass facade. On the basis of numerical results it has been observed that the annual thermal and electrical energy are 480.81 kWh and 469.87 kWh respectively. The yearly overall thermal energy generated by the system has been calculated as 1729.84 kWh. It is also observed that the room air temperature increases by 5–6 °C than the ambient air temperature for a typical winter day.

Experimental Validation of Hybrid Photovoltaic-Thermal (PV/T) Greenhouse Dryer under Forced Mode

In this communication, a thermal model has been developed to predict the performance of hybrid photovoltaic-thermal (PV/T) greenhouse (roof type even span) dryer under forced mode. Based on energy balance, analytical expressions for temperatures of greenhouse air and produce (grape) surface as a function of design and climatic parameters have been developed. The analytical expressions for instantaneous and overall thermal efficiencies have also been developed. The experimental validations have also been carried out for greenhouse room air temperature, crop produce temperature and moisture evaporated etc. under composite climate of New Delhi (28°35'N, 77°12'E, 216 m above MSL). It has been observed that the developed thermal model was in well agreement with experimental data. It has been found that the overall thermal efficiency of hybrid PV/T greenhouse dryer varies from 33 percent to 37.8 percent.

A case study of a typical 2.32 kW P stand-alone photovoltaic (SAPV) in composite climate of New Delhi (India)

This paper presents rigorous experimental outdoor performance of a 2.32 kW P stand-alone photovoltaic (SAPV) system in New Delhi (India) for four weather types in each month such as clear, hazy, partially cloudy/foggy and fully cloudy/foggy weather conditions respectively. The daily power generated from the existing SAPV system was experimentally found in the range of 4–6 kW h/day depending on the prevailing sky conditions. The number of days and daily power generated corresponding to four weather types in each month were used to determine monthly and subsequently annual power generation from the existing SAPV system. There are three daily load profiles with and without earth to air heat exchanger suitable for three seasons like summer (3.75–6.15 kW h/day), winter (2.79–5.19 kW h/day) and rainy (3.75 kW h/day). The hourly efficiency of the SAPV system components are determined and presented in this paper. The life cycle cost (LCC) analysis for the existing typical SAPV system is carried out to determine unit cost of electricity. The effect of annual degradation rate of PV system efficiency is also presented in this paper. The energy production factor (EPF) and the energy payback time (EPBT) of the SAPV system was also determined and presented in this paper.

Comparison of internal heat transfer coefficients in passive solar stills by different thermal models: An experimental validation

In this paper, an attempt has been made to evaluate the internal heat transfer coefficient of single and double slope passive solar stills in summer as well as winter climatic conditions for three different water depths (0.01, 0.02 and 0.03 m) by various thermal models. The experimental validation of distillate yield using different thermal models was carried out for composite climate of New Delhi, India (latitude 28°35′N, longitude 77°12′E). By comparing theoretical values of hourly yield with experimental data it has been observed that Dunkle's model gives better agreement between theoretical and experimental results. Further, Dunkle's model has been used to evaluate the internal heat transfer coefficient for both single and double slope passive solar stills. With the increase in water depth from 0.01 m to 0.03 m there was a marginal variation in the values of convective heat transfer coefficients. It was also observed that on annual basis output of a single slope single slope solar still is better (499.41 l/m2) as compared with a double slope solar still (464.68 l/m2).

Estimation of internal heat transfer coefficients of a hybrid (PV/T) active solar still

In this paper, an attempt is made to estimate the internal heat transfer coefficients of a deep basin hybrid (PV/T) active solar still. The estimation is based on outdoor experimental observation of hybrid (PV/T) solar still for composite climate of New Delhi (latitude 28°35′N and longitude 77°12′E). The internal heat transfer coefficients are evaluated by using thermal models proposed by various researchers. The comparison of hourly yield predicted using various thermal models to the experimental has also been carried out by evaluating the correlation coefficient and percentage deviation. It is observed that, Kumar and Tiwari model (KTM) better validate the results than the others model. The average annual values of convective heat transfer coefficient for the passive and hybrid (PV/T) active solar still are observed as 0.78 and 2.41 W m −2 K −1, respectively at 0.05 m water depth.

Energy metrics analysis of hybrid – photovoltaic (PV) modules

In this paper, energy metrics (energy pay back time, electricity production factor and life cycle conversion efficiency) of hybrid photovoltaic (PV) modules have been analyzed and presented for the composite climate of New Delhi, India. For this purpose, it is necessary to calculate (1) the energy consumption in making different components of the PV modules and (2) the annual energy (electrical and thermal) available from the hybrid-PV modules. A set of mathematical relations have been reformulated for computation of the energy metrics. The manufacturing energy, material production energy, energy use and distribution energy of the system have been taken into account, to determine the embodied energy for the hybrid-PV modules. The embodied energy and annual energy outputs have been used for evaluation of the energy metrics. For hybrid PV module, it has been observed that the EPBT gets significantly reduced by taking into account the increase in annual energy availability of the thermal energy in addition to the electrical energy. The values of EPF and LCCE of hybrid PV module become higher as expected.

A model for estimation of daylight factor for skylight: An experimental validation using pyramid shape skylight over vault roof mud-house in New Delhi (India)

A model to estimate daylight factor was investigated and validated using experimental hourly inside and outside illuminance data of an existing skylight integrated vault roof mud-house in composite climate of New Delhi. The daylight factor model was found in good agreement with experimental value of daylight factor. This model was modified for different practical horizontal surface levels inside the big and small dome rooms and validated using experimental measured data. The yearly average value of percentage daylight factor for big and small dome skylight rooms was determined as 2% and 6%, respectively. The total annual average artificial lighting energy saving potential of the skylight illuminance in the existing building was estimated as 973 kW h/year; corresponds to 1526 kg/year of CO 2 emission mitigation. Hence, the annual carbon credit potential from skylight mud-house building is € 15.3/year.

Energy and exergy metrics analyses of Hybrid Photovoltaic-Thermal air collector

This paper presents the Energy Pay Back Time (EPBT) of Hybrid Photovoltaic-Thermal (HPVT) air collector based on exergy analysis for composite climate of New Delhi. The exergy metrics namely Electricity Production Factor and Life Cycle Conversion Efficiency in addition to EPBT have also been evaluated by using exergetic output. It has been observed that EPBT of HPVT air collector without balance of system based on exergy and energy output is about 10 years and 2 years, respectively, for single fan operation of the HPVT air collector. The pay back period from economic point of view has also been carried out.

Evaluation and comparison of hourly solar radiation models

In this paper, an attempt has been made to develop a new model to evaluate the hourly solar radiation for composite climate of New Delhi. The comparison of new model for hourly solar radiation has been carried out by using various model proposed by others. The root mean square error (RMSE) and mean bias error (MBE) have been used to compare the accuracy of new and others model. The results show that the ASHRAE and new proposed model estimate hourly solar radiation better for composite climate of New Delhi in comparison to other models. Hourly solar radiation estimated by constants obtained by new model (modified ASHRAE model) for composite climate of India is fairly comparable with measured data. The percentage mean bias error with new constants for New Delhi was found as low as 0.15 and 0% for hourly beam and diffuse radiation, respectively. There is a 1.9–8.5% RMSE between observed and predicted values of beam radiation using new constants for clear days. The statistical analysis has been used for the present study. Copyright © 2008 John Wiley & Sons, Ltd.

Performance evaluation of a hybrid photovoltaic thermal (PV/T) (glass-to-glass) system

In this paper, an attempt is made to evaluate the thermal performance of a hybrid photovoltaic thermal (PV/T) air collector system. The two type of photovoltaic (PV) module namely PV module with glass-to-tedlar and glass-to-glass are considered for performance comparison. The results of both PV modules are compared for composite climate of New Delhi. Analytical expression for solar cell, back surface, outlet air temperatures and an overall thermal efficiency are derived for both cases. It is observed that hybrid air collector with PV module glass-to-glass gives better performance in terms of overall thermal efficiency. Parametric studies are also carried out.

Estimation of Hourly Global Solar Radiation for Composite Climate

In this communication, an attempt has been made to estimate hourly global solar radiation for the composite climate of New Delhi (latitude: 28.58 0 N, longitude: 77.20 0 E, elevation: 216 m above mean sea level) using regression analysis based on the model proposed by Al-Sadah et al. (1990). More than 39000 data of hourly solar radiation on a hori- zontal surface measured at New Delhi were compared with hourly data calculated by various calculation models. Com- parison between estimated and measured values shows that the constants derived for New Delhi provide good estimates of the hourly global radiation except for the morning and evening hours. The present results are comparable with the Liu and Jordan (1960) and Collares-Pereira and Rabl (1979) models which also correlate hourly values and daily totals of the global radiation.

Thermal modeling of a combined system of photovoltaic thermal (PV/T) solar water heater

In this paper, an integrated combined system of a photovoltaic (glass–glass) thermal (PV/T) solar water heater of capacity 200 l has been designed and tested in outdoor condition for composite climate of New Delhi. An analytical expression for characteristic equation for photovoltaic thermal (PV/T) flat plate collector has been derived for different condition as a function of design and climatic parameters. The testing of collector and system were carried out during February–April, 2007. It is observed that the photovoltaic thermal (PV/T) flat plate collector partially covered with PV module gives better thermal and average cell efficiency which is in accordance with the results reported by earlier researchers.

Evaluation of solar radiation and its application for photovoltaic/thermal air collector for Indian composite climate

In this paper, an attempt has been made to evaluate cloudiness/haziness and atmospheric transmittance factors for the composite climate of New Delhi, India by considering the hourly data of global and diffuse radiation obtained for (i) the city region, experimentally observed and (ii) the flat land region obtained from the Department of Indian Meteorology, Pune. Cloudiness/haziness factor for the two models have been determined using simple regression analysis for clear sky condition for New Delhi. The comparison between the cloudiness/haziness and atmospheric transmittance factors for the composite climate of New Delhi for both the models and regions have been made. It has been observed that the cloudiness/haziness and atmospheric transmittance factors obtained by both models gave fair agreement within an accuracy of 0.57%. It has also been observed that there is a significant effect of region on beam and diffuse radiation due to cloudiness/haziness factors as expected. Further the data of solar radiation obtained from the Department of Indian Meteorology, Pune, have been used to evaluate the monthly performance of photovoltaic thermal (PV/T) air collector. It has been found that an overall thermal efficiency and exergy efficiency of PV/T air collector were about 50 and 14%, respectively. Copyright © 2006 John Wiley & Sons, Ltd.

Parametric study of various configurations of hybrid PV/thermal air collector: Experimental validation of theoretical model

In this paper, an attempt has been made to evaluate the overall performance of hybrid PV/thermal (PV/T) air collector. The different configurations of hybrid air collectors which are considered as unglazed and glazed PV/T air heaters, with and without tedlar. Analytical expressions for the temperatures of solar cells, back surface of the module, outlet air and the rate of extraction of useful thermal energy from hybrid PV/T air collectors have been derived. Further an analytical expression similar to Hottel–Whiller–Bliss (HWB) equation for flat plate collector has also been derived in terms of design and climatic parameters. Numerical computations have been carried out for composite climate of New Delhi and the results for different configurations have been compared. The thermal model for unglazed PV/T air heating system has also been validated experimentally for summer climatic conditions. It is observed that glazed hybrid PV/T without tedlar gives the best performance.

Performance evaluation of hybrid PV/thermal water/air heating system: A parametric study

In this paper, a thermal model of an integrated photovoltaic and thermal solar (IPVTS) water/air heating system has been developed. An analytical expression for the temperature of solar cell and water and an overall thermal efficiency of IPVTS system have been derived as a function of climatic and design parameters. Numerical computations have been carried out for composite climate of New Delhi for parametric studies. Four configurations, namely (a) unglazed with tedlar (UGT), (b) glazed with tedlar (GT), (c) unglazed without tedlar (UGWT) and (d) glazed without tedlar (GWT) have been considered. Comparison of the IPVTS system with water and air heater has also been carried out. It is found that the characteristic daily efficiency of IPVTS system with water is higher than with air for all configurations except GWT. It is also observed that an overall thermal efficiency of IPVTS system for summer and winter conditions is about 65% and 77%, respectively.

Study of thermal aspects in open and greenhouse ponds

In this study, thermal aspects, e.g. convective heat transfer coefficients were evaluated and modelled in open and greenhouse pond systems (natural convection). Values of the constants C and n were determined by linear regression analysis from the experimental data. It was observed that the ranges of the convective heat transfer coefficient were strongly dependent upon D/H (Diameter / Height) ratio of the container. It was also observed that the uninsulated container 5 (D/H=5.240) and the insulated container 1 (D/H=0.196) indicate minimum and maximum convective heat transfer coefficient in winter and summer months, respectively. Predicted and experimental values of convective heat transfer coefficients, verified in terms of root mean square of percent deviation, correlation coefficient and error bars (±SD), exhibit fair agreement. The model has been validated for the composite climate of New Delhi. Copyright © 2006 John Wiley & Sons, Ltd.