Tara C. Kandpal

Thermal test procedure for box-type solar cookers

Abstract Some guidelines are provided for thermal evaluation of box-type solar cookers. Suitable thermal tests have been proposed and appropriate parameters identified, which pertain to the solar cooker and are relatively independent of the climatic variables as well as the products cooked. These parameters have been combined into two figures of merit.

Potential of fly ash utilisation in India

A simple framework for the estimation of fly ash utilisation potential in India is presented. It also enables estimation of associated resource savings. Results of some typical calculations are presented and described briefly.

DFIG-Based Wind Power Conversion With Grid Power Leveling for Reduced Gusts

This paper presents a new control strategy for a grid-connected doubly fed induction generator (DFIG)-based wind energy conversion system (WECS). Control strategies for the grid side and rotor side converters placed in the rotor circuit of the DFIG are presented along with the mathematical modeling of the employed configuration of WECS. The proposed topology includes a battery energy storage system (BESS) to reduce the power fluctuations on the grid due to the varying nature and unpredictability of wind. The detailed design, sizing, and modeling of the BESS are given for the grid power leveling. Existing control strategies like the maximum power point extraction of the wind turbine, unity power factor operation of the DFIG are also addressed along with the proposed strategy of “grid power leveling.” An analysis is made in terms of the active power sharing between the DFIG and the grid taking into account the power stored or discharged by the BESS, depending on the available wind energy. The proposed strategy is then simulated in MATLAB-SIMULINK and the developed model is used to predict the behavior. An effort is made to make the work contemporary and unique, compared to the existing literature related to issues governing grid fed DFIG-based WECS.

An approach to the estimation of the value of agricultural residues used as biofuels

A simple demand side approach for estimating the monetary value of agricultural residues used as biofuels is proposed. Some of the important issues involved in the use of biomass feedstocks in coal-fired boilers are briefly discussed along with their implications for the maximum acceptable price estimates for the agricultural residues. Results of some typical calculations are analysed along with the estimates obtained on the basis of a supply side approach (based on production cost) developed earlier. The prevailing market prices of some agricultural residues used as feedstocks for briquetting are also indicated. The results obtained can be used as preliminary indicators for identifying niche areas for immediate/short-term utilization of agriculture residues in boilers for process heating and power generation.

Using renewable energy technologies for domestic cooking in India: a methodology for potential estimation

An attempt has been made to estimate the potential of using biogas plants, solar cookers and improved cookstoves for domestic cooking in India. Based on 1991 statistics on the bovine population and ownership pattern, the potential number of family size biogas plants comes out to be around 38 million in the optimistic scenario whereas, in the realistic scenario it is around 29 million. The potential of improved cookstoves is estimated at about 90 million and that of solar cookers is estimated at about 75 million.

Assessment of availability and costs of some agricultural residues used as feedstocks for biomass gasification and briquetting in India.

An assessment of the availability of agricultural residues as raw materials for biomass gasification and briquetting in India has been made with due consideration to their seasonal and geographical availability dimensions. An attempt to estimate the costs of agricultural residues has also been made.

Thermal test procedure for a paraboloid concentrator solar cooker

Abstract Suitable thermal tests have been identified for performance evaluation of a concentrating solar cooker. These tests provide parameters that characterize the performance of the solar cooker, and are more or less independent of the climatic variables. The overall heat loss factor is obtained from the cooling curve and the optical efficiency factor is determined from the heating curve—both under full load conditions. The performance characteristic curve for the solar cooker is obtained and discussed. The study indicates that the no load test, which is useful in the case of a box type solar cooker, is not appropriate in the case of concentrator type cookers.

Techno-economic evaluation of domestic solar water heating systems in India

The most wide spread thermal use of solar energy, so far, has been for water heating. Solar water heating systems have been commercialized in many counties in the world. Though the technical feasibility of domestic solar water heating systems (DSWHS) has long been established, their financial viability needs to be carefully examined, particularly in tropical countries with relatively lower annual capacity utilization and poor purchasing power of potential users.

Testing of box-type solar cooker: Second figure of merit F2 and its variation with load and number of pots

The performance of a box-type solar cooker can be represented in terms of two figures of merit, F1 and F2. The second figure F2 is a controlling factor in the sensible heating of a load. The present work validates F2 by computing this figure from experimental data by two different procedures and comparing the results. An attempt has also been made to provide some guidelines for selecting a suitable temperature interval for determination of F2. The results of some experiments to study the effect of number of pots and the load on F2 have also been presented. It is recommended that for standardization tests should be conducted at full load.

Barriers to dissemination of renewable energy technologies for cooking

A preliminary effort to identify the barriers to dissemination of renewable energy technologies in developing countries has been made.