DE2702489A1 - PROCESS AND DEVICE FOR OPTIMIZING THE OPERATING POINT OF A HEATING DEVICE, IN PARTICULAR A HEAT PUMP - Google Patents

Abstract

The method serves for the automatic optimisation of the operating point of a heating device, in particular of a heat pump, in which the heat energy of the heating medium (7) flowing through a consumer (9) in the circuit is drawn mainly from a natural primary energy carrier (5) by undercooling in an evaporator (1) by means of an intermediate medium (6) flowing in the circuit. The evaporated intermediate medium (6) containing the evaporation heat is brought to a higher heat content by the supply of auxiliary energy and subsequently the increased heat energy of the intermediate medium (6) is delivered to the heating medium (7) serving as secondary energy carrier by liquefaction. In this case, for controlling the auxiliary-energy supply to the intermediate medium (6), the maximum permitted liquefaction pressure or the maximum permitted liquefaction temperature of a compressor (2) are changed or the volume flow of the heating medium through a liquefier (3) is varied, and in particular via the operating time of the compressor (2). <IMAGE>

Description

Liedl, Nnih _: Citizen Patent attorneys f

81) 00 Munich 22 ■ Steinsdorfstrasse 21 - 22 ■ Telephone 089/29 84

A 7578

Dipl.-Ing. Heinz GERBEET, Panoramastraße 2, 7951 ERLENMOOS

Method and device for optimizing the operating point of a heating device, in particular a heat pump

The invention relates to a method according to the preamble of claim 1 and a device provided for carrying out this method according to the preamble of claim 8.

z / Li 809830/022

2702499

In a heating device of the type mentioned, the heat energy to be delivered to a consumer is predominantly taken from a primary energy source of nature, for example solar energy, the outside air, groundwater or the ground, i.e. geothermal energy, by extracting heat from the primary energy source by undercooling in an evaporator will. The heat of evaporation is absorbed by an intermediate medium, which is then brought to a higher pressure and temperature level in a compressor which is used to supply additional auxiliary energy. This intermediate medium is then fed to a condenser, which transfers the heat of condensation to a secondary energy source, namely the heating medium. The intermediate medium is returned to the evaporator in liquid form via an expansion valve and thus works in a cycle.

The energy supplied to the secondary energy carrier, namely the heating medium, is the heat of evaporation absorbed by the intermediate medium of the primary energy source plus the heat equivalent of the drive power of the compressor. The heating medium also flows in one Circulation, d. H. After heat is given off to the rooms or materials to be heated, it is cooled down and is then rewarmed fed to the condenser.

In a practically realized embodiment of such a A suitably designed fan draws in the heating device, in which the outside air is used as the primary energy source a silencer takes in the outside air with a specified minimum volume and minimum temperature and presses it through an air cooler, which is used as a Evaporator works, and then back to the outside via another silencer. The refrigerant evaporated in the air cooler, which acts as an intermediate medium Is used, removes the heat of evaporation from the air flowing past. This thereby absorbing the heat of evaporation

7578 809830/022 «

evaporated refrigerant is produced by the motor-driven compressor brought to a higher pressure and temperature level. The refrigerant is liquefied in the heating device's condenser, which is designed as a flow heater. Here, the heating medium, which is, for example, heating water, extracts the condensation heat from the refrigerant in a specified minimum quantity and maximum temperature, resulting from the heat of vaporization including the heat equivalent the motor drive power of the compressor. That Heating water experiences a temperature increase as it flows through the instantaneous water heater, which is compensated for in the heating consumers by heat-consuming temperature drops.

Instead of heating water can of course also be used as a heating medium Air are used, which is heated in the condenser by the intermediate medium condensing therein. It can therefore do this the heating air circulated by a fan is heated and the The rooms to be heated are fed to the extraction of heat and fed back to the condenser in the circuit for reheating will.

In view of the economical operation of such heating devices, it is important to have an optimal ratio between the respective Adjust the outside temperature and the flow temperature of the heating medium or the auxiliary energy costs, which are mainly due to the work of the compressor for the intermediate medium are so low as possible to keep. The evaluation of the respective operating point of the heating device can be done with the performance figure e, which should be as high as possible according to the definition given below:

ε - consumed primary energy + auxiliary energy

Auxiliary power

27Ü2489

It follows that the heating costs to be expended are all the lower are, the greater the performance figure, the smaller the auxiliary energy to be used, the smaller the temperature difference between the primary medium and the secondary medium.

In the previously known method for operating the heating devices mentioned, the pre-run temperature of the secondary medium, ie the heating medium, is kept constant and the power is controlled by adding cooled heating medium removed from the return line to the heating medium heated to a constant temperature. The control of the mixture takes place here mostly by a control device which, for. B. in a room heating due to the prevailing outside temperature, brings about the associated mixed temperature.

In this process, the liquefaction temperature of the intermediate medium becomes unnecessarily high for the entire duration of the admixture held and thereby also lowered the performance figure. One persistent However, the high condensing temperature is synonymous with high Wear and tear and short service life of the compressor. In addition, must for the control motor and to overcome the flow resistance Auxiliary energy can be applied in the mixer, which further reduces the overall performance factor.

Since in the known method, the heating device with a constant Operated before running temperature and this via outside temperature-dependent motor-operated mixing devices by way of the return mixture is mixed down, an outside temperature-dependent control adjustment of the heating device is achieved, but the performance figure not optimized because, as mentioned, additional auxiliary energies are required. In addition, since the flow temperature of the heating medium depends on the

7578 809830/02? ·

maximum heating output must be designed, that means maximum Compressor work and high wear of the sealer with less Lifespan.

The object of the invention is therefore to avoid these disadvantages based on creating a method and a device for operating the heating device mentioned, by means of which the operating point of the heating device is optimized directly and at the same time not only the necessary auxiliary energy costs but also the system costs are reduced.

The features of the invention created to solve this problem result from the claims.

The invention is based on the idea of the heating device in such a way to operate that instead of the power control by means of basically lossy admixture directly the operating point of the heating device is continuously or intermittently optimized, d. H. that for example In the case of room heating, the forward temperature of the heating medium is only brought to a value that is necessary for the prevailing weather. It will therefore depend on the prevailing outside temperature, the flow temperature of the heating medium changes according to de m respective needs, so that an optimal coefficient of performance corresponding to the necessary heating output is also achieved.

In practice, this is done by having a control device connected Sensors for outside temperature and flow temperature of the heating medium if the flow temperature deviates from the respectively assigned setpoint provides a steady or step signal that affects the operation of the heater. This influencing can - individually or optionally Combination with each other - either directly on the duty cycle of the

7578 809830/0220

■ fi *

Compressor and / or a change in the maximum permissible condensing pressure or the maximum permissible condensing temperature of the intermediate medium and / or used to change the volume flow of the heating medium through the condenser will. At the same time, it is possible, by means of the signal from the control device, to feed a unit provided in the circuit of the primary energy source to influence the required amount of primary energy depending on the outside temperature by counter-rotating Optimally adapt the power control of the delivery unit. The output signal supplied by the control device can also be used for the control can be used by additional heating at certain outdoor temperature peaks.

In preferred embodiments of the invention, the flow temperature of the heating medium is depending on the outside temperature between a highest and a lowest flow temperature through stepless or step changeover via an outside temperature sensor changed by means of a temperature control device by switching this to a steplessly or steplessly driven by an auxiliary power Temperature or pressure regulator acts, so that by means of the correspondingly controlled compressor, the condensing pressure or the The condensing temperature of the intermediate medium can be optimally adapted to the flow temperature of the heating medium. With increasing outside temperature the forward temperature of the heating medium is reduced and accordingly the required compressor work or the Funded primary energy flow as well as the total auxiliary energy supply decreased, which an increase of the performance figure, an enlargement the maintenance periods and an extension of the life of the compressor. The heating costs reach through this procedure a minimum value.

7578 809830/0228

2702483

The use of a fixed level in its switching points Temperature or pressure regulator for the compressor has moreover compared to the use of a motor-driven pressure regulator Price and maintenance advantages.

Since the heating device according to the invention changes its output depending on the outside temperature and the lowest amount of power is output at the lowest outside temperatures, the heating device can either be equipped with a controllable conveying device for the primary energy and / or it can be advantageous not to use the heating device for the to design full heating output, but only for a certain partial heating output. In the few periods in which higher heating capacities are required and which in Central Europe amount to about 2 to 8% of the annual heating time, the heating device can be equipped with additional heaters that are designed so that the total heat demand can be covered. These additional heaters can work as direct heating or storage heating, preferably in combination with one another. In this way, a minimum of system costs and full utilization of the heating power are achieved with certainty.

The invention is explained in more detail below with reference to the drawing. This shows in:

1 schematically shows the automatic optimization of a heating device by regulating the duty cycle of the compressor and / or by means of power regulation of the primary energy delivery unit;

2 shows the heating device with one influenced by the control device Condensing pressure or temperature regulators for the compressor;

₇₅₇₈ 809830/022

-JT-

FIG. 3 shows an embodiment modified from FIG. 2, in which the condensing pressure or temperature regulator is adjustable depending on the outside temperature;

4 schematically shows the optimization of the heating device by changing the volume flow of the heating medium;

Fig. 5 in the diagram, the figure of merit as a function of the Outside temperature with stepless regulation of the heating device according to the invention compared to the performance figure the usual heating device;

6 shows a comparison of the heating costs with a constant Figure of performance working known heater and the heating device according to the invention and working with optimized performance figure

Fig. 7 in the diagram the power factor as well as the annual heat demand as a function of the outside temperature with stepped Regulation.

As can be seen from Fig. 1 to 4, the heating device shown in each case has as structural components an evaporator 1, a compressor 2, a condenser 3 and an expansion valve 4. The individual heat carriers are the primary energy carrier 5, an intermediate medium 6 and the heating medium 7, which by means of a conveyor unit 8, for example a pump or a fan, is transported in the circuit from the condenser 3 via consumers designed as a heat exchanger 9. The intermediate medium 6 is also circulated by means of the compressor 2 from the evaporator 1 via the condenser 3 and the expansion valve 4.

₇₅₇₈ 809830 / 022t

A control device R compares that of a temperature sensor f2 im Flow line of the heating medium 7 measured flow actual temperature with a flow target temperature, which is determined in the control device R according to the outside temperature measured by means of a temperature sensor f 1 or is specified. If the pre-run actual temperature value differs from the setpoint value beyond a desired tolerance, the control device R sends a signal to the compressor 2 in the sense of switching it on and off, so that thereby the duty cycle of the compressor 2 is controlled and thus also the flow temperature of the heating medium 7 directly via the thermal energy additionally supplied to the intermediate medium 6 as a result being affected.

In all the embodiments described - but only shown in FIG. 1 - the primary energy carrier 5 is otherwise through a delivery unit 10, for example a pump or a fan, fed to the evaporator 1, this delivery unit 10 in its Performance adjustable and, as indicated in Fig. 1, also influenced by the output signal of the control device R in such a way can that depending on the outside temperature, the volume flow of the respective primary energy source 5 supplied to the evaporator 1 changed, d. H. increased with falling outside temperature and with as the outside temperature rises.

Another output signal of the control device R can occur when influence an additional heater Z continuously or in stages. It is advantageous here to provide this additional heater Z within a memory 11, which fulfills the purpose of increasing the total amount, for example total amount of water, of the heating medium 7 in order, for example, when applying the necessary auxiliary energy to be able to use the cheaper night-time electricity

7578 809830/0228

nen, the switch-on frequency of compressor 2 or the delivery unit 10 and the daily peak energy consumption or the to be able to avoid shutdowns that may take place at the relevant times of the day.

In the embodiment according to FIG. 2, the duty cycle of the compressor 2 is determined by a condensing pressure regulator P ₁ , on whose steplessly or steplessly adjustable switching point the control device R acts. Instead, a condensing temperature controller T ₁ can be used with advantage, which is not only cheaper than a condensing pressure controller, but also has a wider range in its response accuracy - as desired - so that the compressor 2 is not switched on too often in heating transition periods . In addition, with such a condensing _{temperature controller T 1,} the respective fluctuation range of the response accuracy can be preselected more easily than with a condensing pressure controller, regardless of whether the fluctuation range of the temperature difference within which no response is to be 6 ° or 1 ° C should be. Furthermore, for safety reasons, a pressure monitor can be superordinate to such a control system.

The embodiment according to FIG. 3 is also the same as in the embodiment According to FIG. 2, regulation via the condensing pressure or temperature controller is provided, but here the change is made the switching point to be provided for the intended condensing pressure regulator P "or the intended condensing temperature regulator T "without assistance by means of a depending on the outside temperature working expansion material sensor f3 causes.

₇₅₇₈ 809830/0229

In the embodiment according to FIG. 4, the output signal of the Control device R is used to change the volume flow of the heating medium. For this purpose, the output of the control device R is included the controllably configured delivery unit 8 for the heating medium 7 or, as indicated by dashed lines, connected to a motor-operated throttle valve MV for the intermediate medium 7.

From the diagram according to FIG. 5, in which the _{coefficient of} performance e norma i of a known heating device and the coefficient of performance ε. One of the heating devices described according to FIGS. 1 to 4 are plotted as a function of the outside temperature, it becomes clear what degree of optimization can be achieved and what economic success is associated with this. The between

the curve ε. and the curve ε, vertical dashed area

opt. normal

the additional heating energy applied by the optimized heating device, with the curve ε. corresponds to a stepless or continuous optimization, which here, for example, with the heating device according to Fig. 1 or 4 is achieved.

Based on the comparison of heating costs according to FIG. 6, in which the heating costs of a known heating device operated with ε = constant are set at 100% , it also emerges that by means of the heating device 23 optimized by the method described, 75% heating costs, based on the long-term annual mean temperatures , can be saved.

On the basis of FIG. 7, the course of the optimized performance figure as a function of the outside temperature at stepped also clearly emerges working controllers. This representation shows to a particular extent that especially in that range of outside temperatures that predominantly prevail in Central Europe, a particularly favorable economic

₇₅₇₈ 809830/0228

due to the respectively optimized performance figure in connection with the Long running time of the individual components of the heating device results. In other words, this means that the temperature ranges from -15 to -5 ° C The low power factor occurring outside temperature only accounts for around 3.2% of the annual heating demand, while, as shown by the The dashed annual heat demand curve can be seen, which has been optimized in stages

Coefficient of performance ε in the largest area of the annual heat demand

Grandpa

occurs. This explains why extremely large savings in heating costs can be achieved due to the optimization of the coefficient of performance when using the same basic devices. Based on the representation of Fig.? It can also be concluded that with the optimization method described, due to the higher performance figures achieved, also a higher heat output of the heating device is achieved, so that it is dimensioned and installed smaller in its maximum dimension can be considered a known heating device that works on the same principle, but without the optimization described.

In addition, it is of course also possible to combine all of the described embodiments - be it method or device - either individually or as a whole.

7578 809830/0220

Le e rs e j te

Claims (18)

Claims ^f 1., 'Method for regulating the pre-running temperature of the heating medium flowing in the circuit through a consumer of a heating device, in particular a heat pump, in which the thermal energy of the heating medium is predominantly withdrawn from a primary energy source of nature by supercooling in an evaporator by means of an intermediate medium flowing in the circuit , the evaporated intermediate medium containing the evaporation heat is brought to a higher heat content by supplying auxiliary energy and then the increased heat energy of the intermediate medium is released by liquefaction to the heating medium serving as a secondary energy carrier, whereby the control of the flow temperature of the heating medium takes place depending in particular on the outside temperature characterized in that, for automatic optimization of the operating point of the heating device, the pre-run temperature of the heating medium is changed as a function of the outside temperature by corresponding heat emission from the intermediate medium and the supply of auxiliary energy to the intermediate medium and / or the supply of primary energy is variably controlled. 2. The method according to claim 1, characterized in that the supply of auxiliary energy to the intermediate medium taking place as a function of the heat output of the intermediate medium to the heating medium is carried out continuously or intermittently or in stages. 3. The method of claim 1 or 2, wherein the intermediate medium the auxiliary energy is supplied by means of a compressor, characterized in that the control of the auxiliary energy supply to the intermediate medium is carried out via the duty cycle of the compressor. 7578 809830/0 22 ORIGINAL INSPECTED -V- _n 4. The method according to any one of claims 1 to 3, characterized in that that to control the supply of auxiliary energy to the intermediate medium the maximum permissible condensing pressure or the maximum permissible condensing temperature of the compressor is changed. 5. The method according to any one of claims 1 to 4, characterized in that that to control the supply of auxiliary energy to the intermediate medium, the volume flow of the heating medium through the condenser is changed will. 6. The method according to any one of claims 1 to 5, characterized in that that to control the supply of auxiliary energy to the intermediate medium, the volume flow of the primary energy source as a function is regulated by the outside temperature. 7. The method according to any one of claims 1 to 6, characterized by ure h, that in a range exceeding a predetermined value, negative outside temperatures instead of or in addition to the Supply of auxiliary energy to the intermediate medium, the flow temperature of the heating medium is increased directly by an additional heater or the like. 8. Device for performing the method according to one of claims 1 to 7 with a R _e gel device, which has an input for a sensor for measuring the pre-run isttempera door of the heating medium, an input for an outside temperature sensor to determine the pre-run target temperature of the Hei ζ medium and an output for influencing the flow temperature according to the determined temperature difference, characterized in that for the direct change of the flow temperature of the heating medium (7) according to the output signal of the control device (R) whose output with a ₇₅₇₈ 809830/022 ³ 2702 ** 9 medium (6) or the auxiliary energy supply to the intermediate medium (6) controlling point (2, P ₁ , P ₂ , T ₁ , T ₃ , 8, 10, MV) of the heating device is connected. 9. Apparatus according to claim 8, characterized in that the output of the control device (R) is connected to the compressor (2) for generating the auxiliary energy for the intermediate medium (6). 10. Apparatus according to claim 9, characterized in that the output signal of the control device (R) controls the duty cycle of the compressor (2). 11. The device according to claim 9 or 10, characterized in that the output of the control device OR) is connected to the compressor (2) via a condensing pressure regulator (P-, P «) or condensing temperature regulator (T ₁ , Τ») which controls this. 12. The device according to claim 11, characterized in that the condensing pressure regulator (P ₁ , P ") or condensing _{temperature regulator (T 1} , TJ is designed with adjustable switching points. 13. The device according to claim 12, characterized in that the condensing _{pressure regulator (P ") or condensing temperature regulator (T 2} ) can be changed in its sound points by means of a temperature sensor (f.) Which works as a function of the outside temperature. 14. Device according to one of claims 8 to 13, characterized in that the output of the control device (R) for changing the volume flow of the heating medium (7) through the condenser (3) with a motor-operated valve (MV) in the return line of the heating medium (7) connected is. 809830/022 "♦ 2702499 15. Device according to one of claims 8 to 14, characterized in that the output of the control device (R) for changing the Volume flow of the heating medium (7) through the condenser (3) with a controllable feed pump (8) in the flow line of the heating medium (7) connected is. 16. Device according to one of claims 8 to 15, characterized in that the output of the control device (R) for changing the volume flow of the primary energy carrier (5) through the evaporator (1) is connected to a controllable delivery unit (10). 17. Device according to one of claims 8 to 16, characterized in that a second output of the control device with a Additional heating (Z) connected to increase the flow temperature of the heating medium (7) in a specified peak outside temperature range is. 18. Apparatus according to claim 17, characterized in that the additional heater (Z) is a direct heater and / or a storage heater (11) in which the additional heater (Z) is installed. ⁷⁵⁷⁸ 809830/022 «