A Polygeneration Process Concept for Hybrid Solar and Biomass Power Plant

Chapter 2State-of-the-Art Concentrated Solar Thermal Technologies for End Use Applications

This chapter mainly focuses on the present status of solar thermal technologies for low grade heat to high grade heat applications.

2.1 Solar Thermal Technologies for Low Grade Heat Applications

A solar water heater consists of a collector to collect solar energy and an insulated storage tank to store hot water. The solar energy incident on the absorber panel, coated with selected coating, transfers the heat to the riser pipes underneath the absorber panel. The water passing through the risers get heated up and is delivered to the storage tank. The re-circulation of the same water through the absorber panel in the collector raises the temperature to 80 °C (maximum) on a good, sunny day. The total system with solar collector, storage tank, and pipelines is called a solar hot water system. Broadly, the solar water heating systems consist of two categories: closed loop systems and open loop systems. In the first system, heat exchangers are installed to protect the system from hard water obtained from bore wells or from freezing temperatures in cold regions. In the other, either a thermosiphon or forced circulation system, the water in the system is open to the atmosphere at one point or another. The thermosiphon systems are simple and relatively inexpensive. They are suitable for domestic and small institutional systems, provided the water is treated and potable in quality. The forced circulation ...