DE2818543A1 - Combined domestic heat and power system - has gas turbine driving heat pump to recover waste heat via heat exchanger - Google Patents

Abstract

The gas turbine supplied from an oil fired combustion chamber drives its own compressor and the compressor of a heat pump. There is a starting motor on the same shaft. The exhaust from the turbine passes through a regenerative heat exchanger and then through a heat exchanger in which it gives up heat to a domestic heating circuit. It is finally exhausted through a heat exchanger which forms the source of the heat pump. The gas from the heat pump compressor passes through a heat exchanger in which it also heats the domestic heating circuit. It is then expanded in a turbine and returned to the source exchanger.

Description

Heat generation plant

The invention relates to a heat generation system according to the preamble of claim 1.

Such compound systems are recently for the sake of better Energy utilization has moved more into the general interest again. Known plants this type used the waste heat of the internal combustion engine for heating purposes, whereas the machine driven by the internal combustion engine, a generator for generating of electrical energy. The electrical energy is thereby in the public Grid fed.

Despite the advantage of a very high degree of primary energy utilization Such systems have the disadvantage that they are sensitive to maintenance and also can only be used meaningfully within a certain minimum size.

The object of the invention is to specify a heat generation system, which is undemanding in maintenance and which is also used in very small systems, e.g. B. can be used for normal single-family homes.

According to the invention, this object is achieved by the characterizing features solved by claim 1. Thanks to the use of turbo machines, the system becomes maintenance-insensitive. Due to the design of the machine as a heat pump, the Mechanical energy given off by the internal combustion engine can be used in full for heating purposes, in addition, heat energy can be beneficially withdrawn from the environment. As a result, the effective efficiency of the system can be increased even further. The attachment is therefore also worthwhile for smaller units. The use of turbo machinery also has the advantage over piston engines that it is quiet, which is important when in use is particularly important in single-family homes or similar consumer-oriented systems.

To improve the efficiency of energy generation with the heat pump to shape, the expansion of the working medium in the heat pump circuit of the high- to the low-pressure side via an expansion turbine, which their gives off mechanical energy to the drive of the heat pump.

This allows some of the heat pump's compression work to be recovered will. With a suitable design, the system can also be bivalent with little effort be designed, d. H.

it can also generate heat directly via the burner and via heat exchangers are given to the heat consumer.

In a particularly simple manner, the environment in the heat pump circuit thereby heat can be withdrawn, that the heat pump circuit as an open circuit is operated, with ambient air serving as the working medium. But there is also a closed loop design for the Heat pump conceivable, whereby either a working medium present in gaseous form in the entire circuit, z. B. a noble gas, or a vaporizable or liquefiable refrigerant can serve as a working medium.

The invention is based on an embodiment shown in the drawing briefly explained below; the figure shows in the form of a block diagram a heat generating system according to the invention.

The core of the heat generation system is a machine set that from a compressor 1 operating on the turbo principle, from a power turbine 2, from a heat pump 3, which also works according to the turbo principle, and one Expansion turbine 4 consists. In the illustrated embodiment, all Turbomachines arranged coaxially to one another and rigidly to one another in terms of drive coupled.

For starting up and operating the system as a pure oil burner the machine set can be driven by an electric motor 14 via a freewheel 13. Between the compressor 1 and the power turbine 2, a combustion chamber 5 is arranged, the the fuel (arrow), e.g. B. tieizöl is supplied. The compressor sucks in air from the environment, compresses it and conveys a part directly into the combustion chamber inside, in which due to the combustion the pressure and temperature of the gas continues be raised. Some of the compressed air is released before entering the combustion chamber 5 warmed up in the recuperator 6. From the gas emerging from the combustion chamber 5 will the power turbine 2 is applied, which drives the compressor 1 and the heat pump 3. The exhaust gas expanded in the turbine 2 passes through the recuperator 6, a useful heat exchanger 7 and another heat exchanger 8 to the outside; after passing through the relaxed Exhaust gas through the named heat exchanger is the initially still contained waste heat largely withdrawn. The recuperator 6 is connected upstream of the useful heat exchanger 7, because the exhaust gases emerging directly from the power turbine 2 are for recycling the temperature of the waste heat for heating purposes is too high; it's made of thermodynamic Reasons more expedient to use part of this waste heat to generate working gas. After partial cooling of the exhaust gases in the recuperator 6, a useful heat exchanger can 7 so that the heat absorption side is applied, which has a heat cycle for a Heat consumer 10 feeds.

In addition to the aforementioned compressor 1, the power turbine 2 also nor a heat pump 3 driven, which in the illustrated embodiment of the Heat generation system is arranged in a closed working circuit. In the heat pump working cycle should be a noble gas, z. B. helium. Of the The working circuit of the heat pump is essentially formed by an ilochet temperature heat exchanger 9, the already mentioned expansion turbine 4 and a low-temperature heat exchanger 8th.

The working medium is in the heat pump 3 is largely adiabatically compressed and at such a temperature raised so one for heating purposes exploitable temperature gradient compared to the normal room temperature or the heat transfer medium in the fleizungskreislauf given is. In the high-temperature heat exchanger 9, the working medium is inserted Work is withdrawn in the form of heat and transferred to the heating circuit or

the heat consumer 1o delivered. But it still cooled down Highly tensioned working medium can now be relaxed in the expansion turbine 4, the mechanical energy recovered in this case for driving the heat pump 3 with can be exploited. Due to the largely adiabatic expansion of the working medium there is a very strong cooling in it, so that a temperature gradient of the Exhaust gas of the working turbine 2 behind the useful heat exchanger 7 compared to the relaxed The working medium of the heat pump circuit exists. Those in the exhaust of the power turbine residual waste heat still contained after the useful heat exchanger 7 can be stored in the low-temperature heat exchanger 8 can still be used to preheat the working medium. The exhaust leaves the Heat exchanger 8 cooled down very much, so that in this respect as little heat as possible unused into the open air. The heat exchanger 8 can be installed on the exhaust side according to Art an injector pump, whereby ambient air with through the heat exchanger is torn through. As a result, the ambient air can still have heat in the low-temperature heat exchanger 8 withdrawn.

In order to be able to operate the system even when there is little heat demand the shaft train with the power turbine 2, the heat pump 3 and the expansion turbine 4 can be decoupled from the compressor 1 via the coupling 12. Also is a with a suitable switching element closable bypass line 15 provided over the heated gases exiting the combustion chamber directly to the useful heat exchanger 7 can be directed. In this mode of operation, the compressor is powered by the electric motor 14 driven via the freewheel 13. The whole system then has a similar effect conventional oil burner, the compressor 1 as an air blower for the burner 5 serves. It is then only the primary energy contained in the supplied heating oil used directly for heating purposes.

Instead of the closed heat pump circuit operated with an inert gas An open circuit operated with ambient air can also be provided will. It can e.g. B. be provided that the circuit behind the expansion turbine 4 is open; d. This means that the expansion turbine exits into the open air and that the air sucked in from the environment by the heat pump 3 absorbs heat the heat exchanger 8 flows through it. Of course, entry into and the outlet from the heat pump circuit is as far away from each other as possible be arranged so that a short circuit between entry and exit does not occur can. Constant removal of working medium from the environment means that the in the Heat content contained in ambient air is constantly used to good effect; those in the Air expelled again after passing through the heat pump circuit is colder than the surrounding area. Even when using an open circuit, which is operated with ambient air as the working medium is a preheating of the Air before entering the heat pump in the low-temperature heat exchanger 8 makes sense, Here, too, the residual heat of the exhaust gas from the power turbine 2 is sensibly utilized will.

The use of one at all points of the heat pump cycle in The working medium present in the form of a gas - be it in a closed, be it in a open circuit - offers the possibility of part of the work done by the heat pump Recover compression work via the expansion turbine 4. here is the idea of using low-maintenance and quietly running turbo machines continued in a consistent manner. The turbo machines offer a small construction volume a high wet and volume throughput, even with minor changes in condition Allowing high amounts of energy to be implemented in the working medium.

When using an evaporable or releasable refrigerant As a working medium in a closed heat pump circuit, it is more appropriate to instead of the expansion turbine 4 to provide an expansion throttle 11, which the Separates high pressure side from the low pressure side. The Iloch temperature heat exchanger 9 then works as a condenser in which the compressed refrigerant is removed by heat extraction is liquefied; the low-temperature heat exchanger 8 then works as an evaporator, in which heat is extracted from the ambient air or the exhaust gas. The usage such a refrigerant allows very large changes in state in the working medium and accordingly also the generation of very large usable temperature gradients. The disadvantage of this is that the compression work of the heat pump cannot be recovered is.

Claims (7)

Claims heat generation system with a mechanical energy as well Internal combustion engine generating waste heat and with a work machine driven by it the energy generation, further with at least one of the exhaust gases of the internal combustion engine Useful heat exchanger charged on the heat absorption side for transfer and utilization the waste heat to or from a heat consumer, d u r c h g e -k e n n z e i c h n e t that the internal combustion engine is a Casturbinenanlage (1, 5, 2) and the A working machine coupled with it based on the principle of the centrifugal compressor working heat pump (3), the flow in a thermodynamic cycle of a working medium is included, which after exiting the heat pump (3) a heat exchanger (9) for transferring and utilizing the heat from the heat pump (3) also has gained thermal energy to the or a consumer (10). 2. Heat generating system according to claim 1, d a d u r c h g e k e n n z e i c h n e t that in the circuit of the heat pump (3) behind the heat exchanger (9) an expansion turbine (4) is arranged, which is mechanically connected to the drive the heat pump (3) is coupled. «. Irme generating plant according to claim 1 or 2, d a -d u r c h g e k e n n n g e n e t that the heat pump cycle with ambient air in one open circuit is operated. 4. Heat generating system according to claim 1 or 2, d a -d u r c h g It is not noted that the heat pump circuit with an inert gas, preferably with a noble gas, e.g. B. helium, is operated in a closed circuit. 5. Heat generating system according to claim 1 or 2, d a -d u r c h g I do not know that the heat pump cycle with a liquefiable or evaporable refrigerant is operated in a closed circuit and that a refrigerant evaporator (8) arranged in the inlet of the heat pump absorbs heat can be acted upon by exhaust gases from the gas turbine system (1, 5 »2). 6. Heat generating system according to one of claims 1 to 5, d a d u R e k e k e n n n e i n e t that the working gas generator of the gas turbine plant is designed as a free piston machine. 7. Heat generating system according to one of claims 1 to 5, d a d u It is noted that the compressor (1) of the gas turbine system (1, 5, 2) can be driven by itself (14) and by the power turbine (2) and the The heat pump (3) can be uncoupled (12) and that the in the combustion chamber (5) of the gas turbine system (1, 5, 2) generated hot gases by bypassing the power turbine (2) directly the useful heat exchanger (7) can be supplied on the heat absorption side.