Solar energy which is incident on the earth surface is mostly in diffused form. Hence, ordinary solar water heating technology is able to supply only low-temperature hot water (40–70 °C), primarily used for residential water and space heating. This range of temperature can hardly meet specific energy demand such as food processes, dairy processes and other industrial process heat requirement. Hence to utilize this diffused form of solar energy eff. Solar energy which is incident on the earth surface is mostly in diffused form. Hence, ordinary solar water heating technology is able to supply only low-temperature hot water (40–70 °C), primarily used for residential water and space heating. This range of temperature can hardly meet specific energy demand such as food processes, dairy processes and other industrial process heat requirement. Hence to utilize this diffused form of solar energy efficiently for heating in domestic or industrial applications, solar concentrators have to be used for generating temperatures in the range of 80–250 °C. The medium temperature applications can vary from domestic like cooking, boiling or dairy processes etc. to industrial like heat treatment, sterilizing, dyeing etc. This paper illustrates design and development of various concentrating solar thermal technologies along with its application in Indian market. The paper briefly reviews the need of such technologies; potential markets; and barriers and recommendations for deployment of available concentrated solar thermal technologies used for generation of medium temperature (80–250 °C). The paper focuses on the cases of successful implementation of the technology all over the country and also the government efforts to promote its use further for making it a cheaper and an alternative source of energy to fossil fuels for heating applications.••Medium temperature applicationScheffler reflectorOf all the renewable sources of energy available, solar energy is the most abundant one. The sun emits energy at a rate of 3.8×1023 kW, out of which only 60% reaches the earth surface. It is worth noting that about 0.1% of this energy, when converted at an efficiency of 10% would generate four times the world's total generating capacity of about 3000 GW. Solar energy can be used for thermal energy or power generation using photovoltaic or solar thermal technology. Solar thermal devices are of two types; concentrating and non-concentrating. Non-concentrating devices can generate a fluid temperature in the range of 40–70 °C since most of the solar radiation incident on the earth surface is in diffused form. Some of the energy demands for domestic needs can be fulfilled within this range of temperature but not all. Also the industrial energy demands are still at higher temperature. However such demands can be met by using concentrating type of solar thermal devices where temperature in the range of 80–250 °C can be attained easily because of high concentration ratio. Most of the concentrated solar power (CSP) development had been focused on electricity generation at MW scale due to economy of scale of operation. However, there is a large scope for replacement of fossil fuels/electricity used for thermal energy applications by solar energy.The building sector consumes 35% of the total energy demand, of which 75%. Heat from sun's rays can be harnessed to be provided to a variety of applications. But in general, sun's rays are too diffuse to be of direct use in these applications. So solar concentrators are used to collect and concentrate sun's rays to heat up a working fluid to the required temperature. The following paper discusses the basic principle, desi. 3.1. BarriersThe barriers for adoption of solar concentrator technology include technological, economical, institutional and social. Of these, the economical barrier is usually the main constraint. Economic theory suggests that new technology is often perceived as expensive by investors due to information asymmetry or relatively higher payback period. However, high investment cost, difficulty in obtaining bank loans and inadequate government support often leads to the failure of new technology. The most important economic factor to influence the adoption of a solar concentrator is its price. Economic viability alone does not guarantee penetration of solar concentrators in Indian market but it is the first and foremost criterion for rejection of any project (Fig. 11).3.2. Recommendations to governmentThe following recommendations will help government to focus on overcoming barriers, which are currently most problematic for implementation of concentrated solar thermal technologies. 1) Large scale awareness campaigns targeted at the end consumers and decision makers in the industry and institutions most suitable for solar thermal process heat. 2) Financial incentive.
