Combined Heat and Power (CHP)

Adsorption Systems

Combined Heat and Power (CHP)

Combined heat and power, also called cogeneration, is an efficient approach to generating electric power and useful thermal energy for heating or cooling from a single fuel source. Instead of purchasing electricity from the grid and producing heat in an on-site furnace or boiler, a CHP generator provides both energy services in one energy-efficient step.

CHP plants can be found in three sectors: the electric power sector (plants whose primary purpose is to produce electricity for public sale); and the industrial and commercial sectors (where the CHP facility is usually intended to provide electricity and steam to the host facility, such as a factory). More than 85% of all generating capacity sited at industrial and commercial facilities uses CHP technology.

Industrial applications with constant thermal and electricity demands are ideal candidates for CHP. In the industrial sector, CHP is most likely to be found in energy-intensive manufacturing, especially those that generate combustible byproducts. The majority of industrial CHP capacity can be found in the chemicals, petroleum refining, and paper industries. The food and primary metals industries contain much of the remaining CHP. In the commercial sector, CHP is often used for building or campus heating and air conditioning, such as at college campuses and hospitals.

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Adsorption Systems

Sorption refrigeration technologies such as absorption and/or adsorption are thermally driven systems, in which the conventional mechanical compressor of the common vapour compression cycle is replaced by a ‘thermal compressor’ and a sorbent. The sorbent can be either solid in the case of adsorption systems or liquid for absorption systems. When the sorbent is heated, it desorbs the refrigerant vapour at the condenser pressure. The vapour is then liquefied in the condenser, flows through an expansion valve and enters the evaporator. When the sorbent is cooled, it reabsorbs vapour and thus maintains low pressure in the evaporator. The liquefied refrigerant in the evaporator absorbs heat from the refrigerated space and vaporises, producing the cooling effect.

Adsorption refrigeration unlike absorption and vapour compression systems, is an inherently cyclical process and multiple adsorbent beds are necessary to provide approximately continuous capacity. Adsorption systems inherently require large heat transfer surfaces to transfer heat to and from the adsorbent materials which automatically makes cost an issue. High efficiency systems require that heat of adsorption be recovered to provide part of the heat needed to regenerate the adsorbent. These regenerative cycles consequently need multiples of two-bed heat exchangers and complex heat transfer loops and controls to recover and use waste heat as the heat exchangers cycle between adsorbing and desorbing refrigerant.

Our adsorption chillers have a capacity range of 50 to 700 kW.