Delhi Climatic Conditions Research Articles

Performance Analyses of Photovoltaic Thermal Integrated Concentrator Collector Combined With Single Effect Absorption Cooling Cycle: Constant Flow Rate Mode

Abstract In the present communication, performance analyses of interconnected N number of fully covered semitransparent photovoltaic thermal integrated concentrator collectors combined with single effect vapor absorption refrigeration system have been carried out. The proposed system was analyzed under the constant mass flowrate of collectors’ fluid. Mathematical expressions have also been derived for generator temperature of the absorption unit as a function of both design and operating parameters. Further, simulations have been performed for a typical day of May month of New Delhi climatic conditions. Performance parameters have been evaluated such as collector exit temperature, generator inlet temperature, electrical power output, electrical efficiency, overall thermal energy gain, instantaneous thermal efficiency, overall exergy gain and coefficient of performance of the absorption system. The simulation code has been written in matlab. From the present analyses, the following salient conclusions have been drawn: Operating generator temperature of the absorption system is suitable for five number of photovoltaic thermal-integrated parabolic concentrator collector connected in series. The proposed system will continue operating for 5 h during May month in New Delhi climate conditions. The maximum solar coefficient of performance, refrigeration coefficient of performance, and exergy coefficient of performance are reported as 0.1551, 0.8344, and 0.2697, respectively, for the proposed novel system under given design and operating conditions. Additionally, the effects of other design parameters of this novel system have also been investigated.

Air Pollution a Major Health Hazard In Future

Population, pollution and poverty are the major problems faced by the globe. These problems are interconnected with each other. Population is the major problem that leads to other problems. The population explosion along with urbanization and industrialization has greatly increased the intensity of environmental pollution. More than two million annual deaths and billions of cases of diseases are attributed to pollution. All over the world, people experience the negative effects of environmental degradation ecosystems decline, including water shortage, fisheries depletion, natural disasters due to deforestation and unsafe management and disposal of toxic and dangerous wastes and products. Indigenous peoples suffer directly from the degradation of the ecosystems that they rely upon for their livelihoods. Climate change is exacerbating many of these negative effects of environmental degradation on human health and wellbeing and is also causing new ones, including an increase in extreme weather events such as hot, cold spells of temperature or wet or dry spells of rainfall or cyclones or floods. Last year floods in States of Kerala and Karnataka were also attributed to climatic changes. Recent Delhi climatic conditions are also very alarming. The above facts clearly show the close link between the environment and the enjoyment of human rights, and justify an integrated approach to environment and human rights. The good practices were collected at the international, national and regional levels in collaboration through regional/sub-regional consultations as well as questionnaires and surveys Environmental factors must be favorable for the existence and development of living organisms. It is prime responsibility of human to protect, preserve and to sustain nature for the well being of every organism on this earth.

Thermal Modeling of Opaque and Semi-Transparent Photovoltaic (PV) Module

Photovoltaic (PV) module is one of the simplest technologies to convert the solar energy into the useful electrical energy. In the present paper, an attempt has been made to develop a simplified analytical expression for solar cell temperature and solar cell electrical efficiency of opaque and semi-transparent photovoltaic module in the terms of design and climatic parameters. Based on the energy balance of opaque and semi-transparent PV module, the performance parameters, namely, solar cell temperature, solar cell electrical efficiency, module efficiency and electrical power output have been evaluated for a typical clear day of May month of New Delhi climatic condition data taken from IMD (Indian Meteorological Department), Pune, India. The numerical simulations have been made on the MATLAB software. Based on the numerical computation, the effect of back cover opaque and semitransparent tedlar of module on the performance parameters has been investigated. From the results and discussion, it is found that the performance of photovoltaic module is very sensitive to the module temperature. Further, it is concluded that the semi-transparent photovoltaic module is more efficient than the opaque one. Thus, by the application of semi-transparent PV module in the design of stand-alone and rooftop PV system, the overall energy requirement and performance can be improved for same occupied area.

Simulation performance of single slope solar still by using iteration method for convective heat transfer coefficient

In the present paper, an attempt has been made to simulate the performance of solar still by using iteration method for an internal convective heat and evaporative (mass) transfer coefficient which are used in basic energy balance equations. The energy balance is based on the first law of thermodynamics as a function of design and climatic parameters respectively. The internal convective heat transfer coefficient plays a significant role in the performance of solar still. The iteration method based on Kumar and Tiwari model (KTM), which has not been considered earlier by any authors, has been adopted for numerical computation for the convective heat transfer coefficient (hcw). Based on numerical computation for New Delhi climatic condition, it has been observed that the numerical values of hourly change of an internal convective heat transfer coefficient (hcw) vary between 1.3 to 1.5 W/m2 0C, after fourth iteration process which is reduced by 11.7% in comparison with the first iteration.

Exergy analysis of N-photovoltaic thermal-compound parabolic concentrator (N-PVT-CPC) collector for constant collection temperature for vapor absorption refrigeration (VAR) system

In the present paper, the operating parameters of N-fully covered semitransparent photovoltaic thermal-compound parabolic concentrator (PVT-CPC) collector for constant collection temperature mode have been analyzed on the basis of an overall exergy analysis. The proposed system for a given design and climatic parameters will be applicable to the vapor absorption refrigeration system. The analyses are based on basic energy balance of each components, namely, solar cell, absorber plate, concentrator, flowing fluid, etc. Numerical computations have been carried out for New Delhi climatic condition by using MATLAB R2015a. The performance of the proposed system has also been compared with the performance of photovoltaic thermal-flat plate collector (PVT-FPC), conventional flat plate-compound parabolic concentrator (FPC-CPC) and conventional flat plate collector (FPC). Following conclusions have been made:(i)An overall exergy of N-fully covered semitransparent PVT-CPC system decreases with the increase in constant collection temperature,(ii)An overall thermal energy of N-fully covered semitransparent PVT-CPC system increases with the decrease in packing factor (βc) and.(iii)PVT-CPC and PVT-FPC with fully covered semitransparent are self-sustained collectors to be used for vapor absorption refrigeration system.The proposed system will be most appropriate for vapor absorption refrigeration (VAR) systems.

Energy metrics analysis of N identical evacuated tubular collectors integrated single slope solar still

In this paper, theoretical analysis of single slope solar still (SS) integrated with N identical evacuated tubular collectors (N-ETC-SS) has been performed on the basis of energy metrics. The proposed system has been analyzed considering four categories of weather condition for each month of year for New Delhi climatic condition. Results of the proposed N-ETC-SS has been compared with SS integrated with N identical photovoltaic thermal (PVT) flat plate collectors (N-PVT-FPC-SS), SS integrated with N identical PVT compound parabolic concentrator collectors (N-PVT-CPC-SS) and conventional SS (CSS). It has been concluded that N-ETC-SS performs best on the basis of exergy based energy metrics followed by N-PVT-FPC-SS, CSS and N-PVT-CPC-SS. The value of exergy based energy payback time is lower by 40.38%, 102.78% and 166.58%; energy production factor is higher by 28.57%, 50.79% and 61.90% and life cycle conversion efficiency is higher by 44.83%, 65.52% and 75.86% for the proposed N-ETC-SS than N-PVT-FPC-SS, CSS and N-PVT-CPC-SS respectively.

Energy metrics analysis of N identical evacuated tubular collectors integrated double slope solar still

This paper deals with the theoretical analysis of double slope solar still (DS) integrated with N identical evacuated tubular collectors (N-ETC-DS) on the basis of energy metrics. The analysis has been done considering four types of weather condition for each month of year for New Delhi climatic condition. Results of the proposed N-ETC-DS has been compared with DS integrated with N identical photovoltaic thermal (PVT) flat plate collectors (N-PVT-FPC-DS), DS integrated with N identical PVT compound parabolic concentrator collectors (N-PVT-CPC-DS) and conventional DS (CDS). It has been concluded that N-ETC-DS performs best on the basis of exergy based energy payback time, energy production factor and life cycle conversion efficiency followed by N-PVT-FPC-DS, CDS and N-PVT-CPC-DS.

Quantitative Assessment of Phase Change Material Utilization for Building Cooling Load Abatement in Composite Climatic Condition

The global trend of energy consumption shows that buildings consume around 48% of the total energy, of which, over 50% is for heating and cooling applications. This study elucidates on cooling load reduction with phase change material (PCM) incorporation in a building envelope. PCM provides thermal shielding due to isothermal heat storage during phase change. PCM selection depends upon its phase change temperature, thermal capacity, and thermal conductivity, as they play a vital role in assessing their impact on energy conservation in buildings. The uniqueness of this study underlies in the fact that it focuses on the utilization of PCM for New Delhi (28.54°N, 77.19°E) climatic conditions and adjudges the suitability of three commercially available PCMs, based on the overall heat load reduction and their characteristic charging/discharging. The study aims at finding an optimum melting and solidification temperature of the PCM such that it may be discharged during the night by releasing the heat gained during the day and mark its suitability. The results of mathematical modeling indicate that as per the design conditions, the melting/solidification temperature of 34 °C is suitable for New Delhi to absorb the peak intensity of solar irradiation during summer. Based on the thermophysical properties in literature (Pluss Advanced Technologies Pvt. Ltd., 2015, “Technical Data Sheet of savE® HS29, PLUSS-TDS-DOC-304 Version R0,” Pluss Advanced Technologies Pvt. Ltd., Gurgaon, India. Pluss Advanced Technologies Pvt. Ltd., 2015, “Technical Data Sheet of savE® OM32, PLUSS-TDS-DOC-394 Version R0,” Pluss Advanced Technologies Pvt. Ltd., Gurgaon, India. Pluss Advanced Technologies Pvt. Ltd., 2012, “Technical Data Sheet - savEVR HS34, Doc:305,” Pluss Advanced Technologies Pvt. Ltd., Gurgaon, India), mathematical modeling showed HS34 to be suitable for New Delhi among the three PCMs. To ratify this, characteristic charging and discharging of HS34 is tested experimentally, using differential scanning calorimeter (DSC). The results showed that HS34 is a heterogeneous mixture of hydrated salts having super-cooling of 6 °C, reducing its peak solidification temperature to 30.52 °C during the cooling cycle also making it unsuitable for peak summers in New Delhi.

Performance evaluation of N-photovoltaic thermal (PVT) water collectors partially covered by photovoltaic module connected in series: An experimental study

In present communication, an experimental study has been carried out to evaluate the performance of series connected photovoltaic thermal (PVT) water collector in terms of overall thermal energy gain and overall exergy gain. Earlier developed theoretical model has been validated by performing the experiment in a clear sky day, hazy day and partially cloudy day for New Delhi climatic condition. It was found that theoretical results were in good agreement with experimental results. The annual energy gain, exergy gains, CO2 mitigation, energy matrices and carbon credit of the system have also been discussed. The energy pay-back time was found to be 1.50 and 14.19years on overall thermal energy and exergy basis respectively. Carbon credits earned in a year were Rs. 6321.70 for overall thermal energy gain and Rs. 667.30 for overall exergy gain. For 30years of life time, cost of one unit of electricity was estimated to be Rs. 1.53 on overall thermal energy basis however it was Rs. 14.45 on overall exergy basis.

Application of genetic algorithm with multi-objective function to improve the efficiency of glazed photovoltaic thermal system for New Delhi (India) climatic condition

The aim of this paper is to investigate an improvement in the efficiency of photovoltaic thermal (PVT) system with the help of Genetic Algorithm (GA) with multi-objective functions for New Delhi, India climatic condition. There are several parameters influencing efficiency of PVT system which inter alia include length and depth of the channel, velocity of air fluid flowing into the channel, thickness of the tedlar and glass, temperature of inlet fluid. All these parameters have been considered to optimize the efficiency of the PVT system. An attempt has also been made to model and optimize the parameters of glazed hybrid single channel PVT module considering the two objective functions separately which are: (i) the overall exergy efficiency (ii) the overall thermal efficiency. Using GA, both of the above objective functions are separately optimized and analyzed for each of the two cases: namely, Case-I: Improvement in exergy and thermal efficiency when overall exergy efficiency is optimized and Case-II: Improvement in exergy and thermal efficiency when overall thermal efficiency is optimized. The variables used in GA are those that could be varied, keeping parameters like solar radiation, ambient temperature unchanged in the algorithmic calculation. The electrical and thermal efficiencies after optimization were found 14.15%, 11.88% and 14.08%, 19.48% respectively. Similarly the overall exergy and thermal efficiency are 14.87% and 56.54% respectively for both the cases. It has been observed that there is improvement in overall exergy efficiency and overall thermal efficiency by 4.6% and 13.14% respectively during the optimization process.

Performance analysis in terms of carbon credit earned on annualized uniform cost of glazed hybrid photovoltaic thermal air collector

In this paper, the Performance analysis in terms of effect of carbon credit earned on annualized uniform cost of glazed hybrid photovoltaic thermal air collector on the basis of annual thermal energy and exergy have been analyzed for New Delhi climatic conditions. The effect of interest rates on annualized uniform cost has also been evaluated. For the lifetime (30year) analysis, the carbon emission reduction comes to Rs 109,242 and Rs 25275.6 on the basis of overall thermal energy and exergy basis. It has also been observed that there is significant decrease in annualized uniform cost due to carbon credit earned.

A solar still augmented with an evacuated tube collector in forced mode

A single slope solar still has been integrated with an evacuated tube collector (ETC) and operates in forced mode. Thermal model of integrated system has been developed to predict performance of solar still under New Delhi (India) climatic conditions. The daily yield has been obtained as 3.47kg for basin water depth 0.01m and at mass flow rate of 0.006kg/s. However, the optimum performance has been found to be at mass flow rate of 0.06kg/s for basin water depth 0.03m. The optimum daily yield has been obtained as 3.9kg with energy and exergy efficiencies as 33.8% and 2.6% respectively during typical summer day. The average annual yield per unit of solar collector area has been estimated higher than the natural mode.

Optimization of number of collectors for integrated PV/T hybrid active solar still

The aim of this paper is to optimize the number of collectors for PV/T hybrid active solar still. The number of PV/T collectors connected in series has been integrated with the basin of solar still. The optimization of number of collectors for different heat capacity of water has been carried out on the basis of energy and exergy. Expressions of inner glass, outer glass and water temperature have been derived for the hybrid active solar system. For the numerical computations data of a summer day (May 22, 2008) for Delhi climatic condition have been used. It has been observed that with increase of the mass of water in the basin increases the optimum number of collector. However the daily and exergy efficiency decreases linearly and nonlinearly with increase of water mass. It has been observed that the maximum yield occurs at N = 4 for 50 kg of water mass on the basis of exergy efficiency. The thermal model has also been experimentally validated.

Analysis of PV/T flat plate water collectors connected in series

Photovoltaic–thermal (PV/T) technology refers to the integration of a PV and a conventional solar thermal collector in a single piece of equipment. In this paper we evaluate the performance of partially covered flat plate water collectors connected in series using theoretical modeling. PV is used to run the DC motor, which circulates the water in a forced mode. Analytical expressions for N collectors connected in series are derived by using basic energy balance equations and computer based thermal models. This paper shows the detailed analysis of thermal energy, exergy and electrical energy yield by varying the number of collectors by considering four weather conditions (a, b, c and d type) for five different cities (New Delhi, Bangalore, Mumbai, Srinagar, and Jodhpur) of India. Annual thermal and electrical energy yield is also evaluated for four different series and parallel combination of collectors for comparison purpose considering New Delhi conditions. This paper also gives the total carbon credit earned by the hybrid PV/T water heater investigated as per norms of Kyoto Protocol for New Delhi climatic conditions. Cost analysis has also been carried out. It is observed that the collectors partially covered by PV module combines the production of hot water and electricity generation and it is beneficial for the users whose primary requirement is hot water production and collectors fully covered by PV is beneficial for the users whose primary requirement is electricity generation. We have also found that if this type of system is installed only in 10% of the total residential houses in Delhi then the total carbon credit earned by PV/T water heaters in terms of thermal energy is USD $144.5 millions per annum and in terms of exergy is USD $14.3 millions per annum, respectively.

Performance analysis of a conventional PV/T mixed mode dryer under no load condition

A solar dryer integrated with photovoltaic powered DC fan has been designed and installed at Solar Energy Park, Indian Institute of Technology Delhi. The dryer has been coupled to a solar air heater having blackened surface of absorber for improved energy collection efficiency and a drying chamber with chimney. An analytical expression for characteristic equation for photovoltaic/thermal mixed mode dryer has been derived as a function of design and climatic parameters. The experiment was carried out for forced mode under no load conditions during April 2008 and validated with theoretical results for New Delhi climatic condition. This paper also shows the detailed analysis of thermal energy, exergy, and electrical energy gain by considering four weather conditions (a, b, c, and d type) for five different cities (New Delhi, Bangalore, Mumbai, Srinagar, and Jodhpur) of India. Copyright © 2009 John Wiley & Sons, Ltd.

Thermal modelling, validation and exergetic analysis of a hybrid Photovoltaic/Thermal (PV/T) active solar still

This paper presents the thermal analysis of a self sustainable, new design of hybrid photovoltaic/thermal (PV/T) active solar distillation system. The experiments were conducted for 24 h (7am-7am) for the New Delhi (India) climatic conditions on typical days during the month of April 2006 for water at different depths (i.e., 0.05, 0.10, 0.15 m) in order to validate the experimental results, a thermal model was developed. The theoretical results obtained for basin water temperature and distillate yields are in fair agreement with experimental results. Further, the exergetic and energetic analysis of passive and hybrid active solar still inferred that the average annual exergy efficiency of hybrid active solar still is higher than passive solar still almost by 25%, while the energy efficiency is lower by 24%.

Life Cycle Cost Analysis and Carbon Credit Earned by Hybrid PV/T Solar Water Heater for Delhi Climatic Conditions

In this communication, a study has been carried out to evaluate the life cycle cost analysis and carbon credit earned by hybrid PV/T solar water heater. The study has been based on thermal, electrical and exergy output of water heater. The solar water heater is installed at Solar Energy Park, IIT Delhi. The annual energy and exergy gain have been evaluated by considering four types of weather conditions (A, B, C and D Type) of New Delhi and considering a case that the hot water is withdrawal two times in the afternoon and two times in the evening in a day. This paper gives the total carbon credit earned by hybrid PV/T water heater as per norms of Kyoto Protocol for Delhi climatic conditions. We have found that (i) the cost/kWh is higher in case of exergy when compared with cost/kWh on the basis of thermal energy (ii) if this type of system is installed at 10% of the total residential houses in Delhi then the total carbon credit earned by PV/T water heater annually in terms of thermal energy is Rs. 105.6 cores and in terms of exergy is Rs. 10.2 cores respectively. The thermal energy has wider applications in the hu- man's life. It can be generally utilized in the form of either low grade (low temperature) or high grade (high tempera- ture). The temperature profiles of the photovoltaic (PV) module in a non-steady state condition with respect to time have studied (1). The overall electrical efficiency of the PV module can be increased by increasing the packing factor (PF) and reducing the temperature of the PV module by us- ing the thermal energy associated with the PV module (2, 3). The carrier of thermal energy associated with the PV module may be either air or water. Once thermal energy withdrawal is integrated with the photovoltaic (PV) module, it is referred as hybrid PV/T system. Photovoltaic-thermal (PV/T) technology refers to the integration of a PV module and conventional solar thermal collector in a single piece of equipment. The rationale behind the hybrid concept is that a solar cell converts solar radiation to electrical energy with peak efficiency in the range of 9- 12%, depending on specific solar-cell type and thermal en- ergy through water heating. More than 80% of the solar ra- diation falling on photovoltaic (PV) cells is not converted to electricity, but either reflected or converted to thermal en- ergy. In view of this, hybrid photovoltaic and thermal (PV/T) collectors are introduced to simultaneously generate electric- ity and thermal power (4). The PV/T water heating system, two types of combi-

Life Cycle Cost Analysis and Carbon Credit Earned by Hybrid PV/T Solar Water Heater for Delhi Climatic Conditions

Life Cycle Cost Analysis and Carbon Credit Earned by Hybrid PV/T Solar Water Heater for Delhi Climatic Conditions

Effect of Cover Inclination and Water Depth on Performance of a Solar Still for Indian Climatic Conditions

Effects of condensing cover inclination and water depth on the convective heat transfer coefficient and yield have been studied for a passive solar still. Three solar stills with an effective basin area of 1m2 each have been studied for three inclinations of condensing cover, namely, 15deg, 30deg, and 45deg. An identical solar still, but with a fixed cover inclination of 30deg, has also been tested to evaluate the effects of varying water depth. Outdoor experiments have been conducted for New Delhi climatic conditions (28°37′N∕77°13′E). Hourly variations of temperatures (water, vapor, and cover) and of distillate yield have been recorded and analyzed to determine convective heat and mass transfer coefficients. The resulting calculative extrapolation of experimental data from clear-day operation shows that the combination of minimum water depth and 15deg inclination of the condensing cover leads to maximum annual distillate yield for the climatic conditions of New Delhi. However, a cover inclination of 45deg is almost equally effective on an annual basis, but with better winter performance.

Annual performance analysis and thermal modelling of passive solar still for different inclinations of condensing cover

This paper reports the annual as well as seasonal performance analysis of single-slope passive solar stills having three different inclinations of condensing cover, namely 15, 30 and 45°. The analysis is based on the experiments conducted throughout the year from June 2004 to May 2005 on one clear day every month. Each experiment has been carried over for 24 h for the New Delhi (Latitude: 28°37′ North and Longitude: 77°13′ East) climatic conditions. It was observed that the 15° inclination of condensing cover gives maximum annual yield and distillation efficiency. The concept of solar fraction has been used for the validation of thermal modelling. The fair agreement has been noted between the values observed experimentally and calculated theoretically for temperatures and yield in all seasons. Copyright © 2007 John Wiley & Sons, Ltd.