Thermal Power Station

Skizze von System eines Blockheizkraftwerkes The practicable domain of application – taking into consideration the required availability – lies in objects with a heat requirement of more than 1 MW/a and more than 4,000 hours of operation per year. Combinations with heat recovery units, heat pumps, and refrigerating machines are possible and very interesting with regard to primary energy.

The operational areas are in particular situated in the fields of industry, agriculture and trade, production units, swimming-pools, hospitals, sport centres, therapy centres, hotels, town halls, army facilities, housing estates, multi-story buildings, and schools.

The degrees of utilisation relate to the heating value Hu and amount to (e.g., in the case of gas oil engines) a total of approx. 85-95% (out of this, electrically more than 30%, in parts more than 40%, and thermically more than 50%). For a comparison, picture 1 demonstrates the degree of effectiveness of other energy producers. For a certain engine type, picture 2 shows the proportioning of the energy flow.

Bildbeschreibender TextDepending on the case of application, within certain limits, a relocation ofthe energy proportions and of the temperature ranges can take place. The picture shows the example of the scale of the individual energy flows.

According to this, 90% of the fuel energy are utilized, 35% of this as electrical energy and 55% as utilizable heat. The 10% losses occurring during the energy conversion originate from generator, radiation, and heat exchanger losses plus the unused remaining heat of the waste gas. Quite often, these heat proportions cannot be fed into the heating circuits due to the low temperature level.

If, however, the possibility exists to supply separate heating circuits with a low temperature level, a total utilization degree of more than 90% is obtainable, e.g., by utilization of the condensation heat. This effectivity degree can be further increased by additional aggregates like heat-pumps. Domains of application for low-temperature heat are the heating of swimming-pools, airheating, floor-heating, and others.

Co-generation sets focus on direct, individual energy supply and take over the supply of residential areas via short-distance utilization heat. The investment costs besides those for operation and maintenance as well as the returns for heat and energy are decisive factors for the total profitability of the unit.

Bildbeschreibender TextThe availability of the electrical capacity is a decisive factor for fixing the price for energy evaluation. Here, a multi-module unit proves to be an advantage. In the case of an employ of e.g., six smaller engines instead of one large one, one can calculate an availability of n-1 = 5 engines.

This available capacity can for example be pre-supplier. In the case of multi-module units, each individual engine can be driven under economical load, i.e., with highest effectivity degree. The partial load sections of the unit are covered by the switching off of individual engines or engine groups.

By means of the multi-engine technology, an extension and adaptation of the unit for new construction sections, etc. is easier to execute. The costs for assembly and spares will be considerably decreased. In the case of several engines, maintenance work as a rule can be carried out without a decrease of the calculated availability.