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We analyse the results from a longitudinal natural field experiment that provides an environmental nudge by reinforcing positive environmental norms. Posters asking individuals to use less paper are pasted on printers (Times) and in office cubicles (Umendall) of two information technology firms around New Delhi, India. A third firm (India Mart) does not get the nudge and serves as our control. During the nudge period, employees of the firms that get the conservation message on average expend a significantly lower number of sheets per day as compared to the pre-nudge period, measured both in terms of paper used and paper wasted. Furthermore, after the nudge is removed, the per capita paper wastage for one of the firms that received it (Times) does not increase significantly over the next month and a half, whereas for the other firm (Umendall) it does but remains significantly lower than the per capita wastage in the pre-nudge period. In terms of total paper used, the nudged firms show a reduction in the number of sheets used several weeks after the nudge is removed. For the control firm, the wastage and usage of printer paper does not change significantly over the duration of the experiment. A robustness check with no nudge intervention done by computing per capita wastage and usage for the same dates exactly one year later does not show a reduction over the same time period and offers support for our conclusions. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents rigorous experimental outdoor performance of a 2.32kWP 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 4–6kWh/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 (3.75–6.15kWh/day), winter (2.79–5.19kWh/day) and rainy (3.75kWh/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. [ABSTRACT FROM AUTHOR]

Abstract: The daylight factor model given by Charted Institute of Building Services Engineers (CIBSE) was modified in this paper to incorporate time variations with respect to zenith angle (θz ) and vertical height (h) of working surface above ground surface which was normalized with central height (H) of skylight dome. The modified model contains constant exponents which are determined using linear regression analysis based on hourly experimental data of inside and outside illuminance for each month of the year 2007–2008. The prediction of modified model is found in good agreement with experimental observed inside illuminance data on the basis of values of root mean square percentage error (e) and correlation coefficient (r). The annual average daylight factor values for big and small dome skylight rooms are determined as 2.3% and 4.4% respectively. The energy saving potential of skylight rooms for selected climatic locations in India is also presented in this paper. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: This paper investigates thermal performance of an existing eco-friendly and low embodied energy vault roof passive house (or mud-house) located at Solar Energy Park of IIT Delhi, New Delhi (India). Based on embodied energy analysis, the energy payback time for the mud-house was determined as 18 years. The embodied energy per unit floor area of R.C.C. building (3702.3MJ/m2) is quiet high as compared to the mud-house (2298.8MJ/m2). The mud-house has three rooms with inverted U-shape roof and remaining three rooms with dome shape roof. A thermal model of the house consisting of six interconnected rooms was developed based on energy balance equations which were solved by using fourth order Runge Kutta numerical method. The predicted six room air temperatures were found in good agreement with the experimental observed data on hourly basis in each month for one year. The annual heating and cooling energy saving potential of the mud-house was determined as 1481 kWh/year and 1813kWh/year respectively for New Delhi composite climate. The total mitigation of CO2 emissions due to both heating and cooling energy saving potential was determined as 5.2 metric tons/year. The annual carbon credit potential of mud-house was determined as € 52/year. Similar results were obtained for the different climatic locations in India. [Copyright &y& Elsevier]

Abstract: In this paper, the variability of F2-layer critical frequency foF2 is examined, using modern digital ionosonde observations at a low-middle latitude station, New Delhi (28.6°N, 77.2°E, Dip 42.4°N). Data used for the present study are the hourly values of foF2 for the periods of high (2001–2002) and low (2004–2006) solar activity. To investigate the foF2 variability, the values of median, lower quartile and upper quartile are estimated at each hour for different seasons, during both the solar activity periods. The variability index (henceforth referred to as VI) of foF2 is then obtained by using inter-quartile difference and its percentage ratio to the median. Results show that VI is in general, lower during daytime hours than by night during high solar activity for all the seasons, while during low solar activity, VI behavior is irregular during all the seasons. A solar activity dependence of VI is found with maximum values during periods of low solar activity in all the seasons except for winter during pre-dawn and post-sunset hours. Comparisons of observations with IRI-2001 model [Bilitza, D. International Reference Ionosphere 2000. Radio Sci. 36 (2), 261–275, 2001] show in general good agreement during both the solar activity periods, with model values lying within inter-quartile range. [Copyright &y& Elsevier]