EP1950511A1 - Heat pump - Google Patents

Abstract

The pump has a coolant circuit including a software-based control unit (7) connected with a pressure sensor (5) and a temperature sensor (6) and having a material data storage (12) for a coolant. The sensors are arranged between an evaporator (4) and a compressor (1) and viewed in a circuit flow direction. Another temperature sensor (8) and another pressure sensor (10) are connected with the unit (7) and viewed in the direction. The sensor (8) is arranged at the circuit before a condenser (2). The sensor (10) is arranged at the circuit between the compressor and an expansion valve (3).

Description

The invention relates to a heat pump according to the preamble of patent claim 1.

A heat pump of the type mentioned is well known. This includes a refrigerant circuit including a compressor, a condenser, an expansion valve, an evaporator, a pressure sensor disposed in the cycle flow direction between the evaporator and the compressor, one in the circulating flow direction; seen between the evaporator and the compressor arranged temperature sensor and a software-based control unit, which is connected to the pressure and the temperature sensor.

The regulation of the heat pump takes place via the control unit to which the measured values are supplied by the mentioned pressure and temperature sensor.

The invention has for its object to further develop a salable heat pump of the type mentioned in that during operation without external measuring apparatus construction at least one efficiency accounting feasible and can be displayed accordingly.

This object is achieved with a heat pump of the type mentioned by the features listed in the characterizing part of patent claim 1.

According to the invention, it is thus provided that for the efficiency accounting of the refrigerant circuit with the aid of the control unit, which comprises a substance data store (in the broader sense a substance database) for at least one refrigerant, in Circulation flow direction seen on the refrigerant circuit in front of the condenser connected to the control unit temperature sensor and seen in the circuit flow direction on the refrigerant circuit between the compressor and the expansion valve connected to the control unit pressure sensor is arranged.

Expressed in other words, it is possible according to the invention with the help of further arranged on the refrigerant circuit sensors for temperature and pressure and a material data storage to perform an efficiency accounting. Such accounting is to be regarded as a safety-relevant feature of the heat pump, since efficiencies also indicate malfunction of the heat pump (for example, compressor defects, loss of refrigerant, contamination or icing of the heat exchanger of the condenser or evaporator), quite apart from an operation at unexpected efficiency anyway undesirable. The balancing is displayed, for example, via a display provided on the control unit. Of course, this can also be arranged at any other location in the surrounding area of the heat pump. Data transmission via the internet is also possible.

An essential feature of the invention further consists, as already mentioned, in the so-called substance database (substance data storage). This is absolutely necessary as it is only possible to determine the balancing values after knowing certain refrigerant characteristics (eg the specific heat capacity of the refrigerant). Such a substance database in which substance data of different refrigerants can be stored (because the heat pump is operated with different refrigerants could be), is currently not known in currently known heat pumps.

Other advantageous development of the heat pump according to the invention will be apparent from the dependent claims.

The heat pump according to the invention, including its advantageous developments according to the dependent claims will be explained in more detail with reference to the drawing of a preferred embodiment.

In the only one FIG. 1 the heat pump according to the invention is shown schematically. In an initially known manner, this consists of a refrigerant circuit with a compressor 1, a condenser 2, an expansion valve 3, an evaporator 4, seen in the circuit flow direction between the evaporator 4 and the compressor 1 arranged pressure sensor 5, seen in the direction of circulation flow between the evaporator. 4 and the compressor 1 arranged temperature sensor 6 and a control unit 7, which is connected to the pressure 5 and the temperature sensor 6. As a refrigerant, for example, R 407 C or R 410 A is used.

The refrigerant circuit works in the usual way as follows: The refrigerant is brought to a higher pressure level with the compressor 1. At the condenser 2, the refrigerant releases heat to a second medium and condenses. A Kältemitteldruckeritspannung is then carried out at the expansion valve 3. At the evaporator 4, the refrigerant is supplied from the outside via another medium heat and thereby evaporated.

It is essential for the heat pump according to the invention that the efficiency accounting of the refrigerant circuit with the aid of the software-based control unit 7, which includes a substance data memory 12 for at least one refrigerant, as seen in Krewärtaufströmungichtung the refrigerant circuit before the condenser 2 connected to the control unit 7 temperature sensor 8 and in the circulation flow direction seen at the refrigerant circuit between the compressor 1 and the expansion valve. 3 is a connected to the control unit 7 pressure sensor 10 is arranged.

This requirement, as explained above, leads to a considerable increase in the information available about: the running system.

Furthermore, according to FIG. 1 provided that viewed in the circuit flow direction on the refrigerant circuit behind the condenser 2, a further temperature sensor 9 is arranged. This improves the accuracy in the efficiency accounting, but is not absolutely necessary, since the temperature at the outlet of the condenser 2 ultimately also from the condenser inlet temperature (measured by the temperature sensor 8) and the material data - at least approximately - can be calculated.

The efficiency accounting possible during ongoing operation of the heat pump ready for sale is as follows:

• Enthalpie am Verdichtereintritt H_ND mit Hilfe des Drucksensors 5, des Temperatursensors 6 und den Stoffdaten;
• Enthalpie am Verdichters H_HD mit Hilfe des Temperatursensors 8, Drucksensors 10 und den Stoffdaten;
• Enthalpie am Expansionsventils H_ExV mit Hilfe des Temperatursensors 9, des Drucksensors 10 und den Stoffdaten.

First, the enthalpy values are calculated with the help of the material data, the temperatures and the pressures, namely:

• Enthalpy at the compressor inlet H _ND with the aid of the pressure sensor 5, the temperature sensor 6 and the substance data;
• Enthalpy at the compressor H _HD with the aid of the temperature sensor 8, pressure sensor 10 and the substance data;
• Enthalpy at the expansion valve H _ExV with the help of the temperature sensor 9, the pressure sensor 10 and the substance data.

The thermal efficiency V _{eff of} the compressor is about 93% (7% heat loss due to radiation). The efficiency of the motor M _{eff of} the compressor is 86%.

The so-called COP value (coefficient of performance), which represents the efficiency accounting, is finally calculated from: $$\mathrm{COP}\mathrm{=}\mathrm{\left(}\mathrm{\left(}{\mathrm{H}}_{\mathrm{HD}}\mathrm{\right)}\mathrm{-}\left({\mathrm{H}}_{\mathrm{hrv}}\right)\mathrm{\right)}\mathrm{/}\mathrm{\left(}\mathrm{\left(}{\mathrm{H}}_{\mathrm{HD}}\mathrm{\right)}\mathrm{-}\left({\mathrm{H}}_{\mathrm{HD}}\right)\mathrm{\right)}\mathrm{*}{\mathrm{V}}_{\mathrm{eff}}\mathrm{*}{\mathrm{M}}_{\mathrm{eff}}$$

Particularly preferably, it is further provided that the compressor 1 has a current measuring sensor 11 (generally: an element for detecting the drive power of the compressor) connected to the control unit 7. Together with the electric power P _{e1 of} the compressor motor (determined with the aid of this current measuring sensor 11 [voltage is known]), the heat output is produced for power balancing (1st stage: efficiency balancing, 2nd stage: power balancing) $$\mathrm{heating\; capacity}\mathrm{=}\mathrm{COP}\mathrm{*}{\mathrm{P}}_{\mathrm{e}\mathrm{1}}$$

These values have not yet been determined in the case of heat pumps ready for sale during operation.

How out FIG. 1 it is further provided that the expansion valve 3 with respect to the expansion of the refrigerant electronically adjustable and connected to the control unit 7. This proviso has the additional advantage that the control unit 7 can set an optimum expansion for the heat pump process on the expansion valve 3 on the basis of the determined temperature and pressure values.

Finally, (not shown separately) temperature sensors are also provided on the non-refrigerant-circuit-side supply and discharge lines of the condenser or the evaporator, which are also connected to the control unit. On the basis of this additional temperature information, an additional evaluation of the heat source or heat sink can take place.

LIST OF REFERENCE NUMBERS

1

compressor

2

capacitor

3

expansion valve

4

verdamper

5

pressure sensor

6

temperature sensor

7

control unit

8th

temperature sensor

9

temperature sensor

10

pressure sensor

11

Element for detecting the drive power of the compressor

12

Material data storage

Claims (4)

Heat pump, comprising a refrigerant circuit comprising a compressor (1), a condenser (2), an expansion valve (3), an evaporator (4), a pressure sensor (5) arranged between the evaporator (4) and the compressor (1) in the circuit flow direction ), a temperature sensor (6) arranged between the evaporator (4) and the compressor (1) in the cycle flow direction, and a control unit (7) connected to the pressure (5) and the temperature sensor (6),
characterized,
in that, for the efficiency accounting of the refrigerant circuit with the aid of the software-based control unit (7), which comprises a substance data memory (12) for at least one refrigerant, viewed in the direction of circulation flow on the refrigerant circuit in front of the condenser (2) a temperature sensor (8) connected to the control unit (7) and In the circuit flow direction seen on the refrigerant circuit between the compressor (1) and the expansion valve (3) with the control unit (7) connected pressure sensor (10) is arranged. Heat pump according to claim 1,
characterized,
that a temperature sensor (9) is arranged behind the condenser (2) in the circuit flow direction as seen at the refrigerant circuit. Heat pump according to claim 1 or 2,
characterized,
in that for balancing the refrigerant circuit of the compressor (1) an element connected to the control unit (7) is provided for detecting the drive power of the compressor (11), preferably a current measuring sensor. Heat pump according to one of claims 1 to 3,
characterized,
in that the expansion valve (3) is electronically controllable and connected to the control unit (7).

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