Articles written in Sadhana
Volume 42 Issue 1 January 2017 pp 63-73
Thermal comfort study was carried out in the hostels of National Institute of Technology Calicut,Kerala, which is located in a warm humid climatic zone of India. Measurements of ambient temperature, globe temperature, relative humidity, air velocity and illuminance were carried out in eight hostels, and in parallel a paper-based survey was conducted among students to know about their Thermal Preference Vote (TPV) and Thermal Sensation Vote (TSV) based on an ASHRAE seven-point scale. Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD) have been evaluated based on Fanger’s theory of thermal comfort by utilizing the field measurements. Preferred operative temperature and neutral effective temperature were obtained based on the Predicted Mean Vote (PMV). Similarly the preferred operative temperature and neutraleffective temperature were identified, for both Thermal Sensation Vote (TSV) and Thermal Preference Vote (TPV). Thermal comfort conditions for 80% satisfaction were also determined in each case. Correlations between the Predicted Mean Vote (PMV) and the Thermal Sensation Vote (TSV) as well as between the Predicted Mean Vote (PMV) and the Thermal Preference Vote (TPV) were obtained.
Volume 44 Issue 1 January 2019 Article ID 0023
This paper presents a finite element method based three-dimensional thermal model for predicting the performance of evacuated U-tube solar collector. Numerically predicted working fluid outlet temperature is compared with the experimental data available in the literature and a good agreement is observed between them. The influence of average solar irradiance on efficiency and useful heat gain rate of the solar collector is studied for two different evacuated tube configurations. Employing water and air as working fluid, copper, aluminiumand brass as U-tube material, and graphite, magnesium oxide and aluminium oxide as filler material and the performance of the evacuated tube solar collector is investigated in detail.
Volume 46 All articles Published: 9 July 2021 Article ID 0137
In the present study, performance of the fabricated evacuated U-tube solar collector integrated parabolic reflector (EUSCIPR) and conventional evacuated U-tube solar collector (CEUSC) are analysed experimentally. With reference to humid climatic conditions, a 3D model is developed for comparing the thermal performance of EUSCIPR with a CEUSC. Developed model is validated with field test data and found in good agreement among them. Heat transfer fluid (HTF) temperature difference, energy intake/heat gain and thermal efficiency of the solar collectors are investigated experimentally at various ambient temperatures and solar intensities. From the experimental investigations, it was observed that, in a sunny day, the energy losses incurred across the solar collectors was high during peak hour (1: 20 PM). From the numerical studies, it is found that within the given operating range, the thermal efficiency of the EUSCIPR is 14.1% higher than CEUSC. Further, for a given inlet condition, the contour plots for variation of HTF temperature along the U-tube of EUSCIPR and CEUSC are predicted numerically, and the obtained results are discussed in detail.