FI73308B - VAETSKEBLANDNING FOER VAERMEPUMP SAOVAEL FOERFARANDE FOER UPPVAERMNING ELLER VAERMEKONDITIONERING AV ETT HUS MED HJAELP AV EN KOMPRESSIONSVAERMEPUMP UNDER ANVAENDNING AV EN SPECIFIK ARBETSVAETSKEBLANDNING. - Google Patents

Description

7 3 3 0 8 Heat pump liquid mixture and method for heating or air conditioning a house by means of a compressor heat pump using a specific working liquid mixture 5 The use of non-azeotropic liquid mixtures in a heat pump 855, 2,474,151, 2,474,666 and 2,497,931).

In particular, Patent Application Publication No. 2,474,151 describes non-azeotropic mixtures of two components which make it possible to increase the performance of a heat pump and thus to reduce the operating costs of said heat pump. However, the described mixtures of the two components do not make it possible to increase the thermal power of a particular compressor.

The use of various liquid mixtures as working fluids for heat pumps is also known from some other publications. Thus, FR patent 2,000,830 aims at very low temperatures by using a working fluid containing R12 or R22 or 20 R502 + R13 or R503 (see definitions below).

GB 1 063 416, on the other hand, relates to a mixture of R23 and R13, the amount of the former in the mixture being 20 to 75 molar *. The invention is based on the use of azeotropic compositions or compositions with a boiling point close to them. The subject of the EP patent application is a refrigeration mixture for use in refrigerators consisting of R22 and R32.

It is an object of the present invention to show that specific liquid mixtures make it possible to increase the heat output produced by a heat pump in relation to the case where the heat pump operates with pure liquid. By using the liquid mixtures obtained according to the invention in a heat pump, it is possible to reduce the investment costs. The use of the liquid mixtures according to the invention proves that the heat capacity of a given heat pump increases without changing the components of the heat pump, in particular the compressor.

There are two classic ways to increase the heat output of a heat pump; the first means is to equip pump 2 73308 with a compressor with the highest possible capacity, which allows a considerable amount of flow to be sucked, but this solution leads to additional investment. Another way to increase the heat capacity of a heat pump is to use a working fluid with a lower 5 boiling point than a regular fluid. In any case, such a substitution leads to a reduction in the performance factor and also to a reduction in the range of applications of the machine, since the critical temperature of a liquid with a lower boiling point is generally lower.

The present invention relates in particular to those classic heat pump applications in which the working fluid used is usually monochlorodifluoromethane (R22 - boiling point: -40 ° C) or dichlorodifluoromethane (R12 - boiling point: -29.8 ° C).

In both classical applications, both of the above liquids can be replaced by azeotropic mixtures of R12 or R22 and a halogenated compound having a boiling point almost identical to the above. These azeotropic mixtures have a slightly lower boiling point than R1 2 and R22, respectively, and behave like pure liquids. Thus, R500 with 73.8% by weight of dichlorodifluoromethane R12 (boiling point: -29.8 ° C) and 26.2% of difluoroethane R152a (boiling point: -24.75 ° C) has a boiling point of -33.5 ° C ; R502, of which 48.8% by weight is chlorodifluoromethane R22 (boiling point: -40.8 ° C) and 51.2 ί chloropentafluoroethane R115 (boiling point: -38.7 ° C), has a boiling point of -45.6 ° C . Mention may also be made of R501, which has 75% by weight of chlorodifluoromethane R22 and 25 t of dichlorodifluoromethane R12 and has a boiling point of 30 -4.40 ° C, which is very close to the boiling point of R22.

The aforementioned halogenated liquids are generally used in heat pump plants for heating and / or residential air conditioning, district heating and low temperature industrial applications 35 such as certain drying or concentration operations.

Monochlorodifluoromethane (R22) or R502 is very often used in heat pumps for space heating 3 73308, which use ground, well or river water as cold heat source, outdoor air or in addition exhaust air and hot water as heating water or room air, which can rise to 55 ° C in warm conditions. . 5 heat sources. Replacing R502 with R22 in the heat pump only slightly increases the heat capacity; instead, it allows for a significant decrease in compression temperature. R12 or R500 are particularly suitable for use at relatively high temperatures, e.g. higher than 50 ° C and low temperatures than 80 ° C.

The principle of the invention is to select a mixture of specific liquids which do not form azeotropes with each other, the mixture being characterized in that it consists of a main component which may be monochlorodifluoromethane (R22) or dichlorodifluoromethane (R12) or an azootope containing one of these liquids. and a lower boiling point minority ingredient which is trifluoromethane (R23 - boiling point: -82.1 ° C) or an azeotrope comprising R23. More specifically, the heat pump liquid mixture according to the invention comprises 95 to 80 inol → R22 or R502 and 5 to 20 mol% of R23, or R503, an azeotropic mixture of 40.1% by weight. I R23 and 59.9% chlorine trifluoromethane (R13).

More specifically, the solution according to the invention is characterized by what is set forth in the characterizing part of claim 1.

In the circulation process of a particular heat pump, under identical operating conditions, with other functions being similar, the evaporation pressure of a mixture of the type described above is higher than the evaporation pressure of the main component, which should be used in pure form.

As a result, the molar volume of the vapors sucked by the compressor is lower, which increases the molar flow of the compressor liquid with a certain cylinder volume and thus also the heat capacity of the heat-35 pump. On the other hand, the use of a working fluid mixture comprising a main component (R22 or R12 or R500 or R501 or R502) and a minority component 4 73308 (R23 or R503)> with a lower boiling point generally results in a decrease in the compression ratio. This increases the quantitative yield in the case of alternative reciprocating compressors, and thus promotes an increase in heat capacity.

5 The higher the molar concentration of the minority component, the higher the capacity. The molar proportion of the low-potency ingredient (R23 or R503) should be between 5 and 20%; in fact, too much of this component results in a decrease in the performance factor and excessive condensing pressure. In fact, the operating range of the compressors is limited by certain operating parameters (compression temperature and draw pressure differences) and in particular by the maximum compression pressure. The condensing pressure of the mixture according to the invention is preferably less than 30 bar.

The method according to the invention is characterized by what is set forth in the characterizing part of claim 3.

The liquid mixtures obtained according to the invention can be used in particular when the temperature of the heat source in the frost is preferably between 20 ° C and 75 ° C and the temperature of the cold heat source is preferably between -15 ° C. . . + 4 0 0 C.

Heat pumps using the mixtures defined above can be of any type. The compressor can be, for example, an oiled reciprocating compressor or a dry reciprocating compressor, a screw wheel compressor or a lamella compressor. The exchangers 25 can be, for example, two-tube exchangers or classic vane exchangers for heat exchange with air.

A backhaul is most preferred; it can be well used when using coaxial exchangers for water / coolant exchange in low power heat pumps; it 30 can be implemented in approximately the same way in an air / coolant exchange circuit according to the device described in FR patent 2,474,666. The heat output produced can vary, for example, between a few kilowatts in heat pumps used in households or several megawatts in heat pumps for large spaces.

A preferred embodiment is described in FR Patent 2,497,913. This method comprises the following steps: 73308 (a) the working fluid mixture used is compressed into a vapor phase, (b) the compressed liquid mixture from step (a) is in heat exchange contact with a relatively cold external fluid, and this contact maintaining the said liquid mixture until almost complete liquefaction, (c) the almost completely liquefied liquid mixture from step (b) comes into heat exchange contact with the coolant defined in step (f) so that the liquid mixture cools further, (d) (c) the pressure of the incoming cooled liquid mixture is lowered; (e) the gassed liquid mixture from step (d) comes into heat exchange contact with a liquid 15 which forms a heat source, the contact being allowed to partially evaporate said gaseous liquid mixture; f) the partially vaporized liquid mixture from step (e) undergoes heat exchange with the almost completely liquefied liquid mixture sent to step (c), said partially evaporated liquid mixture forming said coolant of step (c), the contact conditions allowing the evaporation initiated in step (e) to continue, and the vapor from step (f) sent back to step (a),

The following examples illustrate the use of specific liquid compositions of the invention.

30 Example 1.

Let us examine the water / water-1 heat pump shown in Fig. 1. This heat pump comprises an evaporator E1, to which the mixture is introduced along a pipe 1 and from which it leaves evaporated along a pipe 2 to a compressor K1, where the steam mixture is compressed and exits along a pipe 3 and lauh du 11ime en E2, from which it exits liquefied along the pipe U, after which it 73308 gasifies in the throttle valve D1 and has to be recycled to the evaporator. The evaporator and the condenser are formed by a two-pipe heat exchanger, in which the liquids between which the heat exchange takes place flow countercurrently.

The cold heat source consists of groundwater raised from the groundwater layer. This water enters the evaporator E1 via the pipe 5 at a temperature of 12 ° C and leaves the evaporator E1 via the pipe 6 at a temperature of 5 ° C. The water to be heated by the condenser E2 enters along the pipe 7 and exits along the pipe 8.

Depending on the nature of the heating system and the water inlet temperature, two operating cases are investigated.

A - Radiator heating: 15 Water 1 auh Dutt ime inlet temperatures i 1 a h2 ° C (line Y), water .heated temperature: 50 ° C (line 8).

B - Hob heating:

Water condenser inlet temperature 1 a 20.5 ° C, water 1 operating temperatures i la 3 ^ ° C.

20 The water flows to the evaporator and condenser are a function of the capacity of the heat pump corresponding to the working fluid used.

Table I below shows the results comparing in each case A and B - the performance of a heat pump using pure chlorodifluoromethane (R22).

- operation of a heat pump using a non-atotropic mixture with the mixture containing: 85 molar? » chlorine i i fluorine methane (H 7 2) and 15 mol-J? tr i f 1 u or imethane (K 2 3).

COP means the ratio of the thermal power produced to the compressive force applied to the fluid vu.li-30.

II

35 T 73308

TABLE I

Business case A B

Liquid R 2 2 mixture R 2 2 mixture 5 R22 / R23 R22 / R23 Thermal power (W) 1U 2 6 0 17101 1 ^ 820 18376 COP 3.82 37 ^ 8 U, 56 ΪΓ, ύΙ

Suction pressure (b ar) U, δ 5.72 i », 5 0 5.62

Compression pressure (bar) 20.61+ 25.13 15.15 18.1 + 2 10 Compression ratio h, months 1 +, 39 3.37 3.28

The proposed mixture, compared to pure R22 under identical temperature conditions, in a hot and cold heat source, allows for an increase in thermal power of $ 20.

B0, C0P being virtually unchanged in each case.

The thermal power and COP obtained with the mixture R22 / R23 are also clearly higher than the values that can be obtained with the at-seotropy R502 used alone. For example, in the case of A 10, R502 gives a thermal power of 1 I + 5 I + 5 W - let alone an increase of only 2% relative to pure R22 - and a COP of 3.26. The proposed mixtures can be optimized in composition to obtain an increase in thermal power of more than 20% relative to the pure liquid and identical to the pure liquid by 25 ... ...

COP. However, such performance values cannot be obtained by replacing e.g. R502 with R22 or R500 with R12.

FR patent 2 I + 7I + 151 mentions a mixture of R22 and chlorotrifluoromethane R13 (boiling point = -81.1 + ° C). The mixtures with which the results are obtained comprise 85 mol% of R22 and 15 mol% of R13, and the mixtures are compared in Table II with the results obtained using the above-mentioned mixture R22 / R23 ($ 85 / 15 $).

35 8 73308

TABLE II

jOperation case_j_A _____ | _ B_1 [Mixture [R22 / R2 3 1 R22 / R13! R22 / R23! R22 / R13! I-1. I-1--1-1 5 iTemperature eho (W) 1 17.101! 16.21 k | 18.376 '17. ^ 681 [OOP! 3Λ8! 3, J + 3! * +, 63 | li, 55!

Air pressure (bar)! 5.72 i 5, 65 1 5, 62 i 5.5 * + 1

| I I I I I

[Pur sitting pressure (bar) j 25,13 | 21 +, 37 '18.1 + 2 | 18, 01 j iPuri stus ratio i 1 +, 39 i 1 +, 32 · 3.28 i 3.25 1 io | ! ! ! ! !

I-1. I-1-1-L

Almost identical in operating pressure, the R22 / R23 mixture makes it possible to produce a considerably higher calorific value than the R22 / R13 mixture.

With a heat pump of the water / water or air / water type and using the mixture R22 / R23, the heating temperature is less than 55 ° C and preferably less than or equal to 52 ° C, if it is desired that the compression pressure is less than 30 bar and preferably less than 28 bar.

The molar proportion of R23 in the mixture R22 / R23 or R502 / R23 is preferably between 12 and 18 #. The variation of the water temperature in the condenser is preferably between 5 ° C and 15 ° C in order to be approximately the same as the liquefaction interval of the mixtures according to the invention. In case the liquid is clean, 25 ...

the condensing lamp temperature ex is not so significant compared to the water inlet temperature because once it is basically higher than the heating temperature. In contrast, in the case of a countercurrent water condenser, the corresponding temperatures of the proposed non-azeotropic mixtures at the end of the condensation.

and pressure are a direct function of the water condenser inlet temperature. Thus, in the case of the operation described above, the liquefaction range of mixture A is 8 ° C, as is the variation of water temperature (1+ 2 ° C... 50 ° C).

If the water heated by the heat pump has to reach high temperatures, e sim. higher than 60 ° C, dichloro-difluoromethane (R12) or the azeotropic mixture R500 can be replaced by chlorodifluoromethane (R22) to reduce the high pressure in the circuit. Thus, the mixture according to the invention comprising dichlorodifluoromethane (R12) combined with trifluoromethane (R23) makes it possible, under certain operating conditions, to obtain a higher heat capacity than that obtained with pure R12. Thus, a mixture comprising 87.5% by mole of R12 and $ 12.5 by mole of R23 causes an increase in heat capacity of $ 26 in the case of compressor A at a compressive pressure of nia-10 talar rape rather than 17 bar. The molar proportion of R23 in the mixture of the type R12 / R23 or R500 / R23 is preferably between $ 8 and $ 18. When a water condenser is used, the heating temperature is preferably lower than 75 ° C.

The operation diagram described in FR pat ent i s sa 2 1 + 97 931 provides an additional advantage at the thermal capacity level for a non-azeotropic mixture of a particular liquid. This is the topic of Example 2.

Example 2 20 The operation diagram of a heat pump is shown in Figure 2.

The working fluid mixture exiting the throttle valve through the pipe 9 is partially evaporated in the evaporator E3 cooled by the water of the cold heat source, which water flows against the working fluid, enters the evaporator E3 via the pipe 11 and exits therefrom via the pipe 12. After leaving the evaporator E3 along the pipe 10, the mixture is completely evaporated and possibly overheated in the exchanger EL by means of a countercurrent exchanger with the cooled condensate which enters the EL through the pipe 18 and leaves down the pipe 19.

The gaseous working fluid mixture is sucked into the compressor K1 through the pipe 13 and squeezed out at high pressure along the pipe 1L. It is then cooled and completely liquefied by the condenser s5a E5, into which it enters via the pipe IL and from which it exits as a saturated liquid along the pipe 15.

During condensation in S5, the mixture transfers useful thermal power to the heating water which circulates countercurrently between the inlet pipe 16 and the outlet pipe 17. Once the mixture is liquefied in E5, it passes along line 15 into liquid tank B1 and exits there along line 18; It then cools in the EU exchanger and enters the throttle valve VI via line 19. At the capacity level, this diagram brings an improvement when the working fluid is a mixture of non-azeotropic fluids, as the exchanger EU, where the final evaporation takes place, allows the mixture to reach a higher final boiling point, i.e. a higher suction pressure. At the same time, this method makes it possible to reduce the pleasure of the moles of suction and to reduce the compression ratio.

Table III shows the results obtained with the same mixture and under the same operating conditions as in Example 1.

The results obtained in Example 1 with pure chlorodifluoromethane (R22) are mentioned with reference. The operating model of Figure 2 does not change the performance of a clean liquid heat pump. The mixture specified in Example 1 has the following composition 1-20: Chlorodifluoromethane (R22): $ 85 and trifluoromethane (R23): $ 15. Operating cases A and B are explained in Example 1.

According to the flow chart shown in Figure 1, the selected mixture increases the heat capacity of the plant by $ 28, operating at 25 R22 for case A and 3055 for case B.

On the other hand, the use of the mixture improves chlorodifluoromethane when CO 2 is used by $ 2.8 in case A and by 5.255 in case B.

The diagram in Figure 2 requires an additional investment, which is represented by the exchanger E1, but in general the investment is not expensive.

In the example discussed, the exchanger may consist of two concentric smooth tubes with a contact surface of 0.25 m.

35 11 73308

TABLE III

Toi mint atapaus__A__B__

Liquid__R22 ___ R22 / R23 R22 R22 / R23 5 Thermal power (W) __ 1 U260__1832U 1 ^ 820__19268 OOP__3.52__3.62 U. 56 h, 80

Suction pressure (bar) __ ί, 65__6.10 5.72 __ $, 88

Compression pressure (bar) __ 20.6U__25.09 15.1? __ 1 8.37 S Compression ratio U, U U 1+, 1 1 3.37 3.13 10 I___i___

Example 3.

The use of the azeotropic mixture R502 instead of R22 15 allows a significantly lower compression temperature in the compressor and, in the case of an airtight compressor, abnormal engine heating can be avoided. This advantage becomes important in the case of an air / water heat pump when operating at low outdoor heat temperatures.

Operate with an air / water heat pump using R502. The air flow through the evaporator is 6000 m ^ / h, the inlet temperature is 7 ° C and the relative humidity is $ 86. The water flowing in the condenser is heated to a temperature of 25 U5 ° C to 50 ° C. A non-azeotropic mixture containing 1% by mole of R 503 and 86 mole of R 502 gives the results according to Table IV.

'2 73308

TABLE IV

1 1 1 Seos 1 I Nest-e! R502! R502 / R503! 'i _ i! i II!

I III

5 j Thermal power (W) J 11,932 j 13,531 J

! COP! 2.96! 2.92!

I λ I II

* Compression temperature (C) j 65.2 j 88.7 j! Suction pressure (bar)! 5.53! 6, U7! I lii 1 Compression pressure (bar) j 21.85 [25.20 j 10! _ | _! _ I

The proposed mixture gives a 13% increase in heat capacity relative to R502 when the COP and compression temperature are kept practically the same.

In general, the proportion of R503 in the mixture R502 / R503 or R22 / R503 is preferably between 8 and 15 #; in the mixture R500 / R503 it is preferably between 5 and I5 #.

Example 1 * ♦ 20

Other mixtures have been used in a heat pump of the water / water type and the mixtures have produced an increase in heat output: a) 87 molar # R22 and 13 molar # R503 25 b) 88 molar # R12 and 12 molar # R123. # R503: ac) 90 moles of # R500 and 10 moles of # R23 ad) 92 moles of # R500 and 8 moles of # R503 and 15 moles of # R502 and 15 moles of # R23 : af) 85 molar # R501 and 15 molar # R23 30 g) 87 molar # R501 and 13 molar # R503 The following claims relate to mixtures of the two main ingredients described in the present invention. patent application. It will be appreciated that the invention also encompasses mixtures containing not only the above ingredients but also minor amounts (less than 5 mole percent and 13,7308 preferably less than 1 mole percent) of impurities which do not significantly alter the good behavior of these mixtures when used in heat pumps or for thermal air conditioning in living quarters. These impurities can be, for example, derivatives of non-compliant halogenated hydrocarbons and form by-products in the preparation of the required halogenated derivatives.

Example 5 · 10

Proceed as in Example 1, case B (heating with heating plates).

Below (Table V) are the COP values and the calorific values (in kilowatts) of the basic ingredients R22, R502 and R501 for the various mixtures of the basic ingredients with the minority ingredients R23 and R503. The stated molar fraction is the molar fraction of the minority constituents; e.g., 0.05 corresponds to a mixture of 0.05 molar minority and 0.95 molar base.

It will be seen that optimal results are obtained with a minority ingredient content of about 5 to 20%.

"* 73308

TABLE V

I - 1-1-1! . I! INGREDIENTS! MINORITY INGREDIENT: R 23 i MINORITY INGREDIENT: R 503! j_j___I___1 5 j j Moles-j cop {Thermal I Moles- j CQp | Heat | I I share I I power i share ι i power i! i I I (kW) j j I (kW) j ι-1-1-1-1-1-1-1 ι ι ι ι iii ι j I 0 j 1 +, 56 j 11 +, 82 | 0! It, 56 I 11 +, 82! | | 0.05 jU, 62 117.19 j 0.05 j 1 +, 60 j 16.85 j 10 I R 22 | 0.20 i 1 +, 60 j 19.56! 0.20! 1 +, 58! 19.17 and I 0.30! 1 +, 51 + j 21, 1 + 9 I 0.30 I 1 +, 50! 21.06 j ι ι ι I III ι ι ι 1 I III ι 1-1-1-1-1-1-1-1 1 ι 1 I III 1

1 I I I III I

I I I I III I

j j 0 j 1 +, 30 j 15.12 I 0 I 1 +, 30 j 15.12 | 15 j | 0.05 j 1 +, 38 j 17.52 ι 0.05 | 1 +, 38 j 17.18 | j R 502 | 0.20 j 1 +, 35 j 19.95 | 0.20 1 +, 31 + and 19.55 | j! 0.30 and 1 +, 25 −21.90! 0.30! 1 +, 23! 21.1 * 7 '

1 I I I III I

I I I I III I

I 1-1-1-1-1-1-1

I I I I III I

I I I I III I

I I I I III I

20 j jo j 1 +, 50 j 11 +, 95 j 0 j 1 +, 50! 11 +, 95 ij R 501 j 0.05 j 1 +, 57 j 17.35 j 0.05 j 1 +, 57 j 17.00 jjj 0.20 j 1 +, 55 j 19.75 j 0.20 j 1 +, 51 + j 19.1 + 0 jjj 0.30 jit, 1 + 0 j 21.69 j 0.30 j 1 +, 38 j 21.27!

I I I I III I

ι_ι_1_ι_ | _1_ι_1 25

Example 6.

Operates under the following conditions:

Condenser: water inlet: 20.5 ° C (line 7) 30 water outlet: 3l + ° C (line 8) Evaporator: water inlet: 12 ° C (line 5) water outlet: 5 ° C (line 6)

The results are shown in Table VI.

..J-1; · 15 73308

TABLE VI

I 1-1--1

I PERUS- j! I

'INGREDIENT 1 MINORITY INGREDIENT: R 23 1 MINORITY INGREDIENT: R 503 j

II I I

I 1-1-1-1-1-1-1

I III III I

5! 'Molar *' Thermal 'Molar J pnp | Thermal | I I share I I power iosuus i iteho i! _I I! (kw)! I I (kw) 1

I III III I

I III III I

I III III I

! ! o 1 u, 52! ιο, ο! o>, 52! 10.0 i I I 0.05>, 85 I 11.62 | 0.05> .80 | 11> 3 | 10! R 12! 0.20 '>, 83! 13.79! 0.20> .78 | 13.51!

I J 0.30 >> 2 j 11 +, 80 j 0.30>, 36; 11 +, 50 J

I III III I

j III I I I_I

I III III I

I III III I

I III III I

! ! o>, 36! 11.0! o>, 36 11.0! 15! I 0.05! 1 +, 51 + '12.76! 0.05 '1 +, 50' 12.57 1 1 R 500! 0.20 ji +, 51 15.17! 0.20>, 1 + 6 I 11 +, 86! I j 0.30 j 1+, 21 j 16.28; 0.30>, 17 | 15.95 [

I III III I

I_I_l_i_i_I_i_ '

Claims (6)

Heat pump liquid mixture, characterized in that it consists of a mixture of 5 a) 95 to 80 mol% of R22 or R502 and b) 5 to 20 mol% of R23 or R503: a wherein R22 is ronochlorodifluoromethane, R23 is trifluoromethane, R502 is a mixture of chlorodifluoromethane and chloropentafluoroethane with 48.8% by weight of chlorodifluoromethane and 51.2% by weight of chloropentafluoroethane, and R503 is tri -fluoromethane and monochlorotrifluoromethane in a mixture of 40.1% by weight of trifluoromethane and 59.9% by weight of monochloro-trifluoromethane, wherein component a) of the mixture does not form an azeotrope with component b) of the same mixture. Liquid mixture according to Claim 1, characterized in that it comprises a) 88 to 82 molar-Z R 22 or R 502 and b) 12 to 18 mol-Z R 23. 3. A method for heating a house or operating hot air-20 by means of a compressor pump using an alloy working fluid which takes heat from a heat source at a temperature of -15 to + 40 ° C and transfers heat to a liquid at a temperature of 20 to 75 ° C , and the operation of the pump comprising a condensing step of the working fluid, an expansion step, a steam s sea bucket step and a compression step, characterized in that the working fluid is a mixture containing a) 95 ... 80 mol-Z R12, R22, R500: a, R501 or R502 and b) 5 to 20 mol-Z of R23 or R503, wherein R12 is dichlorodifluoromethane, R500 is a mixture of dichlorodifluoromethane and difluoroethane with 73 , 8% by weight of dichlorodifluoromethane and 26.2% by weight of difluoroethane, R501 is a mixture of chlorodifluoromethane and dichlorodifluoromethane with 75% by weight of chlorodifluoromethane and 35% by weight of dichlorodifluoromethane, and R22, R23, R502 and R503 have the same meaning as in claim 1, wherein component a) of the mixture does not azeotrope with component b) of the same mixture. Il 17 73308 A method according to claim 3, characterized in that the working fluid used is the liquid according to claim 2, and the heat pump produces heat for a liquid having a temperature higher than 20 ° C and an outlet temperature lower than 55 ° C, and receives heat From a heat source with a temperature higher than -15 ° C. Process according to Claim 3, characterized in that a mixture of 92 to 82 mol% of R 12 or R 500 and 8 to 18 mol% of R 23 is used as working fluid, and the heat pump produces heat for a liquid with a temperature higher than 40 ° C and an initial temperature lower than 75 ° C, and receiving heat from a heat source having a temperature above + 5 ° C. Method according to one of Claims 3 to 5, characterized in that the heat pump operates under conditions such that a) the working fluid mixture is compressed into a vapor phase, b) the compressed liquid mixture from step (a) is brought into heat exchange contact with a relatively cold external coolant and keeping in this contact until said liquid mixture is substantially completely liquefied, c) the substantially completely liquefied liquid mixture from step (b) is brought into heat exchange contact with the coolant defined in step (f) so that said liquid mixture is further cooled, d) ( (c) allowing the cooled liquid mixture from step (e) to expand; the expanded liquid mixture from step (d) is brought into 1 heat exchange contact with an external liquid which forms a heat source, the contact conditions allowing said expanded liquid mixture to partially evaporate; The partially vaporized liquid mixture from step e) contacting the heat exchanger with the substantially fully liquefied liquid mixture 18 73308 fed to step (c), wherein the partially evaporated liquid mixture forms the coolant of step (c), and the contact conditions allow the evaporation initiated in step (e) to continue, and (g) The evaporated liquid mixture from step (a) is fed back to step (a). Il 19 73308 Paten tkrav: