DE2744615A1 - Heat pump driven by diesel engine - uses waste heat of exhaust to preheat source and condenses pollutants out of exhaust - Google Patents

Abstract

A heat pump for domestic heating has an evaporator in a pool of outdoor water and a condenser in a warm air duct which provides heating to the building. The compressor of the heat pump is driven by a diesel engine. The exhaust of the diesel engine passes through a heat exchanger in the outdoor pool. This raises the temp. of the source and cools the exhaust. The exhaust can then flow through a further heat exchanger in which it preheats the refrigerant condensate. The performance of the heat pump is improved and polluting constituents of the exhaust are condensed out of it.

Description

Process for the detoxification of the exhaust gases and

Utilizing the waste heat from a diesel engine as a drive for a Heat pump system For the extraction of heating energy from surrounding heat sources a cycle known as a "heat pump" is available.

According to this, a refrigerant is produced by adiabatic evaporation has been brought to a low temperature with the surrounding heat source brought into heat exchange. The heated refrigerant is compressed by means of a compressor brought to a higher temperature level, whereupon it liquefies gives off heat to a heating circuit in a heat exchanger. A procedure which makes use of this circular process, is in the patent applications P 26 34 233.6-13 and P 27 15 075.0.

Work must be done to drive the compressor.

This can be done, for example, by an electric motor. The usage of However, electrical energy to drive such compressors is fundamental bad solution. For every KWh of electricity consumed in this way go into electricity generation in the power plants and in its distribution in the networks about two more KWh of primary energy lost. As a result, the advantages of the Heat pump process through the lossy generation and distribution of the for len Compressor drive required electricity again for the most part economically seen get lost. If what is to be expected, heat pump processes more and more enforce, it would ultimately lead to such a high total power consumption Heat pump systems lead to additional power plants to cover the resulting Would have to be built if required.

In any case, it can be stated that the electric drive of Heat pump Kb pressoren macroeconomically only at a slightly lower rate Consumption of primary energy and would also have other undesirable effects. For this reason, considerations have been made for a long time as to how such compressors could be driven directly by internal combustion engines. The diesel engine is particularly suitable for this, its fuel consumption per Work unit performed is known to be much lower for structural reasons is than e.g. that of a gasoline engine. So could the fuel consumption of a detached single-family house with approx. 170 square meters of living space from approx. 80001 per Year (heating oil) after the changeover to full heat pump heating when used of a diesel engine as a compressor drive can be reduced to approx. 20001 diesel oil. the The use of diesel engines for this purpose has so far failed because of the result associated exhaust problems. The combustion of diesel oil produces, among other things, also nitrogen oxides and sulfur dioxide, which are considered poisonous gases and their Generation is therefore undesirable, especially in residential areas. From both Poison gases arise when burning 1kg of diesel oil, depending on its origin and processing technique during fractionation, between 10 and 30g, i.e. between 1 and 3% of the fuel consumption.

Because so far none of the investment costs for this exhaust gas problem A justifiable solution that seemed possible for this purpose is in particular due to the Development of gas-powered Otto engines has been avoided. This is because Their exhaust gases are almost free of harmful substances from the harmless CO2 and water vapor exist i id can therefore be safely released into the environment. I, sbei is the fuel consumption before gasoline engines per unit of work performed by up to 50% higher, which is why the diesel engine is unquestionably preferable if there are no emissions problems were. On top of that, the storage of liquefied petroleum gas for obvious reasons is both dangerous and technically complex and therefore expensive.

The invention is based on the object of specifying a method with which the exhaust gases used to operate a heat pump compressor Diesel engine is detoxified and its waste heat can also be made usable.

This object is achieved according to the invention with the method according to claim 1 solved.

for a more detailed explanation of the method according to the invention is first the heat pump method according to patent application p 27 15 075.0 briefly as follows described: From a basin filled with water with a capacity of 50m3, for example, a an evaporator immersed in the basin for a first time of the day heat is taken from the heat pump principle and initially transferred to a smaller secondary basin submitted.

From this, the heat is then also generated during a second time of the day Taken according to the heat pump principle for direct heating purposes. In the bigger one Basin k @@ mt it especially during longer cold spells in winter through continued Heat removal to ice formation on the evaporator surface.

A water-ice mixture is formed, the temperature of which is OOC. The liquid phase of the mixture can be e.g.

Conveniently in heat exchange with surrounding heat sources in the pumping process bring when they have a temperature of over 0 ° C, which e.g. also in winter this is often the case with regard to the external air in the densely populated areas of the world is.

The use of a diesel engine to drive the heat pump compressor is made possible according to the invention as follows: The exhaust gases of the diesel engine are by means of a ceramic or metallic pipe with the water from the secondary pool brought into heat exchange, its temperature as described in the patent application P 27 15 075.0 can be at approx. + 200C. The temperature of the exhaust gases depends on Construction and the respective degree of load of the motor between 250 and 4000C, see above that through the walls of the pipeline mentioned an intense heat output the pool water takes place.

After the exhaust gases have been cooled to e.g. + @ 0 ° C db they via a continuation of the aforementioned pipeline through the larger primary basin directed, where they enter into heat exchange with the aforementioned water-ice mixture. at sufficient length of this heat exchanger duct, which also acts as an exhaust pipe @ @ can almost all of the residual heat above 0 ° C dtj exhaust gases for the heat pump process be healthy.

After burning 1kg of diesel oil, the exhaust gases are as follows Amount and composition formed approx. 31009 carbon dioxide, approx. 11509 water vapor, approx. 609 carbon monoxide, approx. 20g sulfur dioxide, approx. 10g nitrogen oxide, other components in traces.

If you bring these gases into heat exchange in the manner described above with the storage basin, the water vapor initially dissolves. Both the nitrogen oxides as well as the sulfur dioxide then go, especially with further cooling in the colder primary basin, in which water mist or

condensate in solution. In the process, the nitrogen ox is formed into the one with what , r a mixture of nitric acid HNO and nitrous acid HNO2. Furthermore, ds SO2 because of its high solubility in water (106.69 / 1 water at OOC) essentially completely in solution, with a partial conversion into sulfurous acid t 2S03 takes place. Because of the very high water formation and the low final temperature due to of the heat shower process, both the acid formation and the dissolution of unreacted residual gases in the water are practically 100X.

Care must be taken when routing the cables that the forming condensates drain in the direction of flow of the exhaust gases in a free gradient so that there is no backflow of condensate. Because of the strong oxidizing Effect of nitric acid, which is known to attack even precious metals, must either suitable ceramic material can be used for the exhaust pipe or else Aluminum, which is quite different from nitric acid in all concentrations behaves indifferently.

The weakly acidic condensate obtained in this way can be used as domestic waste water hit the train and lead with these into the sewerage system. Contains domestic sewage namely in large quantities soapy water and detergent solutions, which due to their alkaline Effect make the wastewater treatment in the sewage treatment plants more difficult. The alkaline effect is completely or partially neutralized by the addition of weak acids.

However, not only nitrogen and sulfur oxides are in the exhaust gas condensate dissolved or bound in the form of their acids, but also others in part as known harmful substances contained in diesel exhaust fumes, such as that because of its carcinogenic effect dreaded 3.4 benzopyrene, which on the manner described above essentially completely from the finally into the open cleaned exhaust gases that arrive is removed.

Finally, it should be mentioned that the engine waste heat that is in the water used for engine cooling flows in by introducing this cooling water directly into the heating circuit or by exchanging heat with the heating circuit as well can be fed to full heating purposes.

The method according to the invention thus enables a) removal of nitrogen and sulfur oxides as well as other pollutants from diesel exhaust gases, b) the recovery of almost all waste heat contained in the exhaust gases, including the in the dissolution and conversion processes, according to a) heat released, c) a environmentally friendly use or derivation of the which is advantageous in terms of wastewater technology Condensates containing toxins in general sewage disposal, and d) the complete recovery of the waste heat flowing into the engine's cooling water.

Overall, the method according to the invention is environmentally friendly Allows the use of diesel engines for the heat pump drive. It also stands the overall system because of the almost complete utilization of all waste heat from the engine the total energy content of diesel fuel with an amount greater than 10 000kcal / kg available. The mode of operation of such a system can be set in such a way that that the two stages of the heat pump process with a coefficient of performance of each over 3.0 take place.

Even under very winter conditions it is achieved that the amount of heat used per kg in the actual heating water circuit Fuel is about 15,000 kcal, the annual average is about 17,000 - 18,000 kcal. For comparison: with conventional oil heating it is a maximum of 600 kcal in operation During the so-called transition periods, this yield even sinks with oil heating still while they increases in heat pump heating.

The coefficient of performance of such a heat pump system can still be due to this be increased that the engine exhaust before they are in heat exchange with the water storage tank get, first brought into direct heat exchange with the return water of the heating and the heating water is only then transferred to the actual heat pump process Ultimately desired or required flow temperature depending on the outside temperature is brought.

Claims (6)

Patent claims: I \ l experience to detoxify the exhaust gases and make them usable the waste heat from a diesel engine as a drive for a heat pump system, thereby g I do not know, because the exhaust gases of the diesel engine through indirect heat exchange with the refrigerant circuit and / or heat exchange with the heating circuit of the heat pump system be cooled to the extent that the pollutants in the exhaust gases at least partially condense or go into solution in the condensate formed,,) ei waste heat from the exhaust gases in the Refrigerant or heating circuit is transferred. 2. The method according to claim 1, characterized in that g e k e n n -z e i c h n e t, that the cooling circuit of the diesel engine in the heating circuit of the heat pump system is performed or brought into heat exchange with this. 3. The method according to claim 1 or 2, for use in a heat pump system with one on the one hand with the refrigerant circuit and on the other hand with the surrounding Heat sources in heat exchange water storage according to patent applications P 26 34 233.6-13 and P 27 15 075.0, it is noted that the exhaust gases of the diesel engine can be brought into heat exchange with the water storage tank. 4. The method according to claim 3, for use in a heat pump system with a water storage tank divided into a primary and a secondary water supply according to patent application P 27 15 075.0, thereby 9 e k e n n z e i chn e t that the Exhaust gases from the diesel engine first with the secondary water supply and then with the primary water supply be brought into heat exchange. 5. The method according to claim 3 or 4, characterized in that g e -k e n n z e i c h n e t that the exhaust gases of the diesel engine initially with the heating circuit and are then brought into heat exchange with the water supply. 6.Verfahren according to any one of claims 1 to 5, characterized g e k e n n I do not know that the condensate from the exhaust gases is otherwise, in general alkaline household sewage is added.