Combined Heat and Power
Combined heat and power (CHP), also referred to as co-generation is a process in which heat recovered from a power generation system is used to generate additional power or provide space, system, or process heating. To be clear, CHP is not a technology but a process comprised of technologies arranged in such a way as to make the most efficient use of resources and, subsequently reduce waste.
A combustion engine fueled by natural gas or diesel fuel can produce electrical power equivalent to 30-48% of the energy content of the fuel used. The remaining energy in the fuel is normally wasted as heat through exhaust and engine cooling via water jacket and/or oil cooler. This heat represents energy that could be put to use in other processes thereby reducing costs, increasing efficiency, decreasing emissions per energy unit captured and providing pre-heating for certain processes.
Engine exhaust temperatures generally range between 850F to 1200F (~450C to 650C) while water jacket coolant temperatures frequently are capable of producing hot water at temperatures of 195F to 210F (90C to 99C). Engine lubricating systems can also be used for heat recovery in engines where such a configuration does not interfere with engine operation. This hot water can be applied to space heating or additional power generation through implementation of an Organic Rankine (ORC) or Kalina Cycle system.
Combined Cooling Heat and Power
Combined Cooling Heat and Power (CCHP) or tri-generation is a variation on the fundamental CHP process that incorporates cooling driven by process heat in order to better accommodate facilities with such a requirement.
Through the implementation of adsorption or absorption chillers it is possible to provide space cooling during times of year when heating is not required. This added efficiency provides benefits on a number of levels. Reduced electrical power use for the generation of space cooling and greater efficiency of fuel use in a generator set are an example of the dual benefit of the addition of such a cooling process.
It should be understood that space cooling is, in fact, removal of heat. This heat represents energy wasted or inputted to an area in the form of heat from equipment and occupants of the space being cooled. Utilization of this heat in the operation of an ORC or Kalina Cycle system can yield additional electrical power generation benefits. Both processes require cooling for proper operation and the MarGin process was developed to use this as an opportunity to provide greater availability of heat for internal processes rather than wasting all the available heat to the atmosphere.
In operational settings where greater cooling demand requires; the integration of mechanical industrial chillers, often centrifugal chillers owing to their high coefficient of performance (COP), will provide greater heat removal at high efficiency. While these chillers require high electrical energy input the generation of this power can be through a CHP process with heat used in additional power production or the operation of adsorption/absorption chillers with heat recovered from the space being cooled also implemented for such purpose.
CHP and Tri-Generation Preliminary Estimate Data Required
The information necessary for a preliminary estimation of equipment capital and operating costs includes: utility usage and peak demand (electrical power, fuel oil, natural gas) information for at least twelve months; heating and cooling requirements as well as space requiring year round heating or cooling such as servers or laundries; facility water usage and wastewater output and; proximity to utilities; space available for installation and; any other special requirements related to grid interconnectivity or emissions available at the time of the request for preliminary review.