Introduction to Trigeneration

Trigeneration refers to the simultaneous generation of electricity and useful heating and cooling from the combustion of a biomass fuel or a solar heat collector. Conventional coal or nuclear-powered power stations convert only about 33% of their input heat to electricity. The remaining 67% emerges from the turbines as low-grade waste heat with no significant local uses so it is usually rejected to the environment. What is Trigeneration In a trigeneration system, the supply of high-temperature heat first drives a gas or steam turbine powered generator and the resulting low-temperature waste heat is then used for water or space heating. Such systems can attain higher … Continue reading

Introduction to Solar Pond

A solar pond is a three-dimensional, open-air pit, filled with water endowed with special properties. It receives solar energy through insulation, then the trapped heat is extracted from it from the water lying at the bottom of the pond. When solar energy falls onto the pond, it heats the water, splitting it into three sections: the first section is the uppermost layer, or Surface Zone, containing fresh water with a low level of salinity. This owes to the fact that salts gather at the bottom. The second layer is the middle layer, called the insulating layer or Insulation Zone, whose … Continue reading

Waste-to-Energy Pathways

Waste-to-energy is the use of modern combustion and biological technologies to recover energy from urban wastes. The conversion of waste material to energy can proceed along three major pathways – thermochemical, biochemical and physicochemical. Thermochemical conversion, characterized by higher temperature and conversion rates, is best suited for lower moisture feedstock and is generally less selective for products. On the other hand, biochemical technologies are more suitable for wet wastes which are rich in organic matter. Thermochemical Conversion The three principal methods of thermochemical conversion are combustion (in excess air), gasification (in reduced air), and pyrolysis (in absence of air). The most … Continue reading

Combined Heat and Power Systems

Combined Heat and Power (CHP), or Cogeneration, is the sequential or simultaneous generation of multiple forms of useful energy (usually mechanical and thermal) in a single, integrated system. In conventional electricity generation systems, about 35% of the energy potential contained in the fuel is converted on average into electricity, whilst the rest is lost as waste heat. CHP systems uses both electricity and heat and therefore can achieve an efficiency of up to 90%, giving energy savings between 15-40% when compared with the separate production of electricity from conventional power stations and of heat from boilers. CHP systems consist of … Continue reading

Biomass Energy and its Promise

Biomass is the material derived from plants that use sunlight to grow which include plant and animal material such as wood from forests, material left over from agricultural and forestry processes, and organic industrial, human and animal wastes. Biomass comes from a variety of sources including wood from natural forests, agricultural residues, agro-industrial wastes, animal manure, organic industrial wastes, municipal solid wastes, sewage sludge etc. When biomass is left lying around on the ground it breaks down over a long period of time, releasing carbon dioxide and its store of energy slowly. By burning biomass its store of energy is released … Continue reading

UHI Effect: Impact on Sustainability

Urban Heat Island (UHI) Effect arises due to absorption of incident radiation from the sun by built surfaces of tall buildings, roof, concrete structures and asphalt roads and then releasing it in the form of heat. The term “urban heat island” describes the built-up areas that are significantly hotter than the surrounding open, natural or rural areas. It occurs on the surface and in the atmosphere. The built surfaces are made of high-percentage of non-reflective and water-resistant construction materials. These materials act as heat sinks that absorb the radiated heat and store it for long time. The UHI Phenomenon Lack … Continue reading