Book - School of Science and Technology

Basic considerations 695Figure 24.6 Combined exhaust heat exchanger/silencerIn general,since the CHP system is unlikely to have sufficient capacity to meet thepeak thermal load in mid-winter,boiler plant of some sort,for emergency standby orparallel operation,will need to be incorporated in the central plant and means for dealingwith this will need to be considered also. When adding heat recovery equipment to anexisting system it is sensible to involve the original designer in order to avoid complications.The right hand side of Figure 24.7 shows the alternatives of series and parallel pipeconnections between the two systems. To avoid complication,details irrelevant to theoperation of the circuits such as isolating valves etc. are not shown in this figure.In most instances,the output of the CHP alternator will be connected,for normalrunning,to a discrete section of the electrical distribution system and,if the central switchgear is properly designed,sub-divided and identified,connection should not present anyproblems. If,however,a significant volume of power export to the public supply isenvisaged or if the alternator is to be used for emergency standby purposes,connection