DE102012101106A1 - Method for operating heating system, involves transferring heat from heat source to heat transfer agent, where specific amount of heat is removed from heat transfer agent such that temperature of heat transfer agent falls - Google Patents

Abstract

The method involves transferring heat from a heat source (1,7) to a heat transfer agent, where a specific amount of heat is removed from the heat transfer agent such that the temperature of the heat transfer agent falls below five degree Celsius. The amount of heat is provided to a load (6) at a certain temperature level. The heat in the heat transfer agent from the heat source is transferred such that the temperature of the heat transfer agent is less or equal to zero degree Celsius and the heat amount is determined such that the temperature of the heat transferee medium is lowered.

Description

The invention relates to a method for operating a heating system and a heating system, which is configured to perform the method.

For example, from the prior art heating systems with photothermal collectors (solar collectors), which are arranged on building roofs and heat a heat transfer medium for hot water supply or heating purposes, known. These heating systems are operated so that (usable) heat is obtained at a certain temperature level for supplying a consumer, depending on the individual components of the heating systems, such as the nature of the solar collector or the memory used, and the interconnection of the components, the heating systems different operate.

In the known heating systems it comes in times of low irradiation on the solar collector, for example, at night, in winter or in bad weather, downtime of the heating systems, which generally reduces the economics of such heating systems.

The object of the invention is to provide a method for operating a heating system and such a heating system, which are improved at least in some aspects over known methods / heating systems and / or represent an alternative to these.

In particular, it is the object of the invention to provide a method for operating a heating system and a heating system configured for carrying out the method, by which the standstill times are avoided.

This object is achieved by a method for operating a heating system according to claim 1 and a heating system according to claim 7.

Preferred embodiments of the method are the subject of the subclaims.

According to the invention, a method of operating a heating system comprises the following method steps.

In a first method step, heat is transferred from at least one heat source to a heat transfer medium such that the heat transfer medium has a specific temperature. In a second and third process step, the heat transfer medium such a certain amount of heat withdrawn that the temperature of the heat transfer medium below 5 ° C, 4 ° C, 3 ° C, 2 ° C or 1 ° C drops / falls, and the amount of heat extracted a consumer provided at a specific, usable temperature level.

The fact that in the process according to the invention the heat transfer medium so much heat is removed that the temperature of the heat transfer medium below 5 ° C, 4 ° C, 3 ° C, 2 ° C or 1 ° C drops / falls, this method can also at times be carried out in which the heat source provides only a small heat yield or the heat source from the available temperature level is very low. For example, if a photothermal collector (solar collector) is used as a heat source, this can by the inventive method even in transitional seasons, in bad weather, in winter or at night - generally in times of low irradiation on the solar collector - if he only slightly the heat transfer medium can heat, be operated because the temperature of the heat transfer medium is "forced" below the temperature level of the solar collector or is less than this by the withdrawal of the amount of heat. The runtime and the yield of the solar collector thereby increase substantially.

The (usable) certain temperature level at which the amount of heat extracted is made available to a consumer in the third process step is preferably between 30 ° C and 55 ° C and more preferably between 35 ° C and 60 ° C and further preferably between 35 ° C-100 ° C. For example, the amount of heat lying at this temperature level is used for heating purposes and / or for providing service water and / or for other processes / purposes.

Preferably, in the method according to the invention, the heat transferred from the heat source to the heat transfer medium in the first method step is stored in a first intermediate store, before the heat transfer medium is deprived of the specific amount of heat in the second method step.

This preferred embodiment of the method according to the invention, the heat supplied by the heat source or heat transferred by the consumer can be used with a time delay.

In a further preferred embodiment of the method according to the invention, such a quantity of heat is removed from the heat transfer medium in the second process step that the temperature of the heat transfer medium is less than or equal to 0 ° C.

In this preferred embodiment of the method according to the invention is as a heat transfer medium, for example, a liquid with a Freezing point of below 0 ° C used, for example, water to which an antifreeze was added, or other liquid whose freezing point is below 0 ° C.

As a result of this embodiment of the method according to the invention, the running time and the yield of the heat source can be further improved or downtimes avoided.

In a further preferred embodiment of the method, in the first method step, heat is transferred to the heat transfer medium such that the temperature of the heat transfer medium is less than or equal to 0 ° C. and the amount of heat in the second method step is determined in such a way that the temperature of the heat transfer medium is lowered further, for example, to minus 10 ° C.

In a further preferred embodiment of the method according to the invention, if, after the first method step, the temperature of the heat transfer medium corresponds to the specific temperature level which is to be made available to the consumer, the heat is made available to the consumer directly. Consequently, if the heat source is able to supply the consumer alone and directly with heat at the specific temperature level, the heat is provided directly to the consumer.

This can also be accomplished, for example, by storing the heat in a second intermediate store during times in which the heat supply can be carried out by the heat source alone and making it directly available to the consumer via the second intermediate store.

In a preferred embodiment of the method according to the invention, if the temperature prevailing in the first buffer store is too high or the temperature which can be supplied by the heat source drops too much, heat is transferred from the first buffer store to the second buffer store and thus the one prevailing in the first buffer store Lowered temperature and the prevailing in the second buffer increases. As a result, a temperature gradient between the heat source and the first intermediate store is preferably provided, so that the heat source does not have to be switched off.

In general, the method according to the invention can be carried out to any desired low temperatures of the heat transfer medium. As a result, heat is used at a very low temperature level for example for heating purposes or for supplying hot water.

The invention also relates to a heating system which is adapted to carry out the method explained above. Such a device is preferably a heating system for providing hot service water and / or space heating.

The device according to the invention preferably comprises as a heat source a photothermal collector or a solar collector, which is able to heat the heat transfer medium or to transfer heat to the heat transfer medium.

The solar collector is, for example, a vacuum solar collector with a particularly low internal hydraulic resistance. As a result, for example, the power consumption of a pump, which is provided for the transport of the heat transfer medium by the vacuum solar collector can be reduced. The viscosity of commonly used heat transfer agents decreases with decreasing temperature. By using the vacuum solar collector with low internal hydraulic resistance, the pump is able to transport the heat transfer medium through the vacuum solar collector with less current consumption.

In addition, the design of the heat source in the form of the vacuum solar collector is advantageous in that there is no accumulation of water in the solar collector when it is in an operating condition below the dew point of water vapor.

Finally, a vacuum solar collector is also advantageous because it can be operated without problems in negative temperature ranges.

Alternatively, other and optionally further heat sources can be used in the heating system according to the invention. This may be, for example, air absorbers, heat exchangers for waste heat from domestic or industrial processes, generally to regenerative thermal heat suppliers or heat sources. The heat sources can be interconnected so that they can be operated individually or in combination.

In the first method step, heat can be supplied to the heat transfer medium via these heat sources such that the heat transfer medium has the specific temperature.

In order to extract the specific amount of heat from the heat transfer medium in the second process step, a heat pump is used in the heating system according to the invention, for example, which extracts the amount of heat so determined on its primary side from the heat transfer medium that the Temperature of the heat transfer medium below 5 ° C, 4 ° C, 3 ° C, 2 ° C or 1 ° C drops / falls.

For example, the heat pump is a directly evaporating, directly condensing, combined or indirect with heat exchangers as evaporator / condenser working heat pump.

In a very preferred embodiment, the heat pump is equipped with a scroll compressor. This heat pump works well at very low temperatures with good efficiency.

In the second process step, heat is removed from the heat transfer medium on the primary side of the heat pump via the heat pump so that the temperature of the heat transfer medium drops below 5 ° C., 4 ° C., 3 ° C., 2 ° C. or 1 ° C. or even drops is less than or equal to 0 ° C, and in the third process step, the amount of heat on the secondary side of the heat pump is made available to a consumer at the specific temperature level.

In this embodiment of the heating system according to the invention, there is the possibility that the heat source (s) can operate in very low temperature ranges / and the entire heating system can make a contribution to the heat supply or heating of a consumer.

When the vacuum solar collector is used as the heat source, it can be operated at temperatures of the conveyed heat transfer medium of less than or equal to 0 ° C, wherein the heat pump removes the heat transfer medium such an amount of heat that the temperature value of the heat transfer medium drops further, for example to minus 10 ° C.

The heating system according to the invention preferably comprises a first intermediate store in which the heat obtained by the heat source (s) can be intermediately stored.

The heat pump of the heating system according to the invention is connected to the first intermediate storage and can withdraw this amount of heat such that the temperature in the first buffer below 5 ° C, 4 ° C, 3 ° C, 2 ° C or 1 ° C drops / falls or is also less than or equal to 0 ° C.

The heat source (s) and the heat pump can either be connected to the first intermediate store via heat exchangers or be connected directly to the latter or can remove / supply the heat transfer medium directly therefrom. The same applies to the second hiss memory explained below.

In a preferred embodiment of the first heat accumulator this is designed as a water or heat transfer medium storage or as a buffer PCM-based (PCM = Phase Change Material) with a certain melting point T1. By temporarily storing the heat in the first buffer, the heat supplied by the heat source (s) can be used in a time-delayed manner.

In a further preferred embodiment of the heating system according to the invention, a second intermediate store is provided in which heat from the heat source (s) can be stored.

The second intermediate store is preferably provided so that, if the temperature value of the heat transfer medium after the first method step corresponds to the determined temperature level which is to be made available to the consumer, i. that the heat source (s) can take over the supply of the consumer alone, the heat is stored in the second buffer.

In a preferred embodiment of the second buffer this is designed as a heating water, hot water tank or as a buffer PCM-based (PCM = Phase Change Material) with a certain melting point T2. The melting points T1 and T2 may be the same or different.

In a preferred embodiment of the heating system according to the invention, this is set up such that, if the temperature in the first buffer is too high or if the temperature which can be supplied by the heat source (s), for example the vacuum solar collector, drops too high, the heat pump generates heat from the first buffer to the second buffer, thereby cooling the first buffer and heating the second buffer.

As a result, the first buffer can be kept at a temperature which is lower than that of the heat source (s) available, whereby the operating times of the heat source (s) can be extended or downtime of the heating system can be avoided. In other words, this can always provide for a temperature gradient between the heat source (s) and the first buffer to be heated.

In a preferred embodiment of the heating system, the heat pump and optionally necessary pumps and / or a controller, which are the Heat transfer of the heat from the / the heat source (s) on the / the temporary storage and / or the heat transfer through the heat pump to the buffer and / or the consumer controls, integrated into the first buffer. As a result, a compact system can be made available, which can easily complement any water-based heating without major assembly activities.

In general, the heating system according to the invention can be operated at arbitrarily low temperatures, in particular when a vacuum solar collector and a heat pump with a scroll compressor are used as the heat source.

In the following, a preferred embodiment of the method according to the invention and a heating system according to the invention will be explained with reference to the attached figure.

The figure shows schematically a structure of a heating system according to the invention, with which the inventive method can be performed.

In the figure, it is a schematic representation of the heating system according to the invention, wherein the heat transfer of heat is indicated on the individual elements by the arrow information.

The individual elements of the heating system are connected by hydraulic lines in which a liquid heat transfer medium flows. For the transport of the heat transfer medium in the lines or for generating a circulation of the heat transfer medium between different elements pumps are provided at suitable locations of the system.

The heating system includes a heat source 1 , This heat source may preferably be one or more heat sources. Examples of the heat source (s) are a solar collector or photothermal collector, a vacuum solar collector, air absorbers, heat exchangers for recovering waste heat from air or waste heat from domestic or industrial processes, waste water, etc. In general, the heat source (s) ( n) 1 to thermal energy suppliers. Preferably, in this embodiment, a vacuum solar collector is used as the heat source.

Furthermore, the device comprises a first buffer 3 and a second cache 2 , The heat source (s) 1 can / can their recovered heat switchable to the first and second buffer 2 . 3 transmit, with the heat source (s) 1 the heat exclusively or in controllable different proportions on the buffers 2 and 3 can transfer. For example, switching valves or points can be used for this regulation.

The second cache 2 may for example be a heat storage for heating water or service water based on water or heat transfer medium or a PCM-based memory with a certain melting temperature T2.

Likewise, the first cache 3 a heat storage medium based on water or heat carrier or a memory PCM-based with a same or different melting temperature T1 as that of the second buffer (if this is also designed as a PCM memory).

At the first cache 3 may preferably still another source of heat 7 put their gained heat on the cache 3 transmits, be provided.

Optionally, the heating system according to the invention can be a controllable heat generator 5 , such as a conventional boiler.

A heat pump 4 is at the first cache 3 connected and can remove this heat or withdraw. The heat pump can be, for example, a directly evaporating, directly condensing, combined or indirectly operating with heat exchangers as evaporator / condenser heat pump.

The heat pump 4 is preferably designed as a heat pump with a scroll compressor.

The heat pump 4 Can the cache 3 taken amount of heat at a higher temperature level a consumer 6 make available or the second cache 2 warm up or the first cache 3 store the amount of heat removed in this. The heat pump can be the consumer 6 directly or indirectly via the heat generator 5 provide heat at the specified temperature level.

At least the heat transfer medium between the heat source (s) 1 and the buffers 2 . 3 circulates, and the heat transfer medium, the between the first cache 3 and the heat pump circulates, is provided with antifreeze, so that the temperature of the heat transfer medium in particular between the / the heat source (s) 1 and the first cache 3 and the temperature of the heat transfer medium between the first buffer 3 and the heat pump 4 may be below 0 ° C.

As can be seen from the figure, the consumer can 6 , For example, a surface heating, with heat (at a desired, usable temperature level) from the second cache 2 , Heat (at a desired, usable temperature level) from the conventional heat generator 5 and heat (at a desired, usable temperature level) from the heat pump 4 be supplied. The consumer 6 can be supplied with heat (at a desired, usable temperature level) either by these elements alone or by a combination of these elements. Also, the consumer can use heat (at a desired, usable temperature level) indirectly via the heat generator 5 from the heat pump 4 or from the second cache 2 be supplied.

In the following, a preferred method, which is performed in the heating system shown, explained.

If the heat delivery capacity of the heat source (s) 1 For example, the irradiation on the (vacuum) solar collector 1 is so strong that heat is available at a temperature level above 30 ° C, this is for direct use by the consumer 6 on the cache 2 transferred, whereby this is heated.

If the heat delivery capacity of the heat source (s) 1 For example, the irradiation on the (vacuum) solar collector 1 , for a direct supply of the second buffer 2 is not sufficient, ie heat not at a temperature level for direct use by the consumer 6 from the solar collector 1 or the heat sources 1 is available, for example, when the temperature level is below 30 ° C, that of the solar collector 1 available heat to the first buffer 3 transferred and cached in this or heated this.

When in times of low irradiation on the solar collector 1 the consumer 6 must be supplied with heat, withdraws the heat pump 4 the first cache 3 Heat and puts it to the consumer 6 at a higher temperature level.

The heat pump 4 works by making the first cache 3 cools very much, with the first cache 3 preferably to a temperature between + 5 ° C, + 4 ° C, + 3 ° C, + 2 ° C, + 1 ° C or 0 ° C and -10 ° C is cooled.

Since solar collectors can operate in winter, during transition seasons, in bad weather and even at night in operating conditions where they can supply heat at a temperature level between + 5 ° C and -10 ° C, due to the strong cooling of the first intermediate storage 3 through the heat pump 4 the solar collector 1 be operated consistently, whereby the term and the solar yield significantly improve or downtime of the solar collector can be avoided.

If the temperature in the first buffer is too high or that of the solar collector 1 If the available temperature drops too high, the heat pump transfers heat from the first buffer 3 to the second cache 2 and thus cools the first buffer 3 and heats the second cache 2 on. This can ensure that there is always a temperature gradient between the solar collector 1 and the first cache.

For the explained operation of the heat pump 4 it is preferred that this has a scroll compressor, whereby the heat pump 4 can work with good efficiencies at these low temperatures.

The solar collector is preferred 1 designed for this operation as a vacuum solar collector. This allows the solar collector to operate at temperatures less than or equal to 0 ° C and below the dew point. That is, in this mode of operation of the illustrated heating system even very low solar yields are effectively used to heat a consumer.

Furthermore, if the temperature in the buffer 2 lower than a certain adjustable threshold, for example 40 ° C, and the temperature in the buffer 3 is greater than a second predetermined threshold, for example 10 ° C, the heat from the buffer 3 through the heat pump 4 in the cache 2 transferred, for example, at a temperature level of 55 ° C, causing the memory 2 is heated. Again, the heat pump is operated such that the first buffer 3 is cooled far.

This operation of the heating system also low solar yields in times where a lower heat demand by the consumer 6 exists, effectively used and in the caches 3 . 2 stored, with the heat pump 4 does not need to be clocked, because when the heat demand by the consumer 6 sinks, the heat pump 4 the excess heat at a higher temperature level on the second buffer 2 can transfer.

As will be apparent from the foregoing description, the present invention provides a method of a corresponding apparatus, which can effectively utilize even a low heat delivery capability of a heat source and can provide a consumer for heat supply.

Claims (7)

Method for operating a heating system, in which - in a first method step, heat is transferred to a heat transfer medium from a heat source ( 1 . 7 ) is transferred, - in a second process step such a certain amount of heat is removed from the heat transfer medium that the temperature of the heat transfer medium below 5 ° C, 4 ° C, 3 ° C, 2 ° C or 1 ° C drops / falls, and - a third step, the amount of heat a consumer ( 6 ) is provided at a certain temperature level. Method according to Claim 1, in which the heat after the first method step is stored in a first intermediate store ( 3 ) is stored and in the second process step, the amount of heat the first buffer ( 3 ) is withdrawn. A method according to claim 1 or 2, wherein the amount of heat is determined such that the temperature of the heat transfer medium in the second method step drops to less than / equal to 0 ° C. Method according to Claim 3, in which the heat transfer medium from the heat source ( 1 . 7 ) In the first method step, heat is transferred such that the temperature of the heat transfer medium is less than or equal to 0 ° C and the amount of heat in the second process step is determined such that the temperature of the heat transfer medium is further lowered. Method according to one of the preceding claims, in which, if the temperature of the heat transfer medium after the first method step corresponds to the determined temperature level, the heat is transferred to the consumer ( 6 ) is provided directly. Method according to Claim 5, in which, if the temperature of the heat transfer medium after the first method step corresponds to the determined temperature level, the heat is stored in a second buffer store ( 2 ) and the consumer ( 6 ) via the second buffer ( 2 ) is provided directly. Heating system, which is adapted to perform the method according to one of claims 1 to 6.

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