AU606542B2 - Heat pump capable of simultaneously supplying cold and hot fluids - Google Patents

Description

"i; ct.. 60 0' 4

AUSTRALIA

PATENTS ACT 1952 COMPLETE SPECIFICATION Form

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged:

U

Pg tr 4 Complete Specification-Lodged; Accepted: Lapsed: Published: Priority: SRelateo, Art: TO BE COMPLETED BY APPLICANT Name of Applicant: 1) OSAKA PREFECTURE Address of Applicant: 2, OTEMAENO-CHO, CHUO-KU, OSAKA, JAPAN NISHIYODO AIR CONDITIONER CO., LTD.

Address of Applicant: 15-10, HIMESATO 1-CHOME NISHIYODOGAWA-KU, OSAKA, JAPAN Actual Inventor: Address for Service: GRIFFITH HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

Complete Specification for the invention entitled: HEAT PUMP CAPABLE OF SIMULTANEOUSLY SUPPLYING COLD AND HOT FLUIDS.

The following statement is a full description of this invention including the best method of performing it known to me:- 1A 1A HEAT PUMP CAPABLE OF SIMULTANEOUSLY SUPPLYING COLD AND HOT FLUIDS BACK GROUND OF THE INVENTION: 1. Field of the Invention: This invention relates to a heat pump capable of simultaneously supplying cold and hot fluids. It has particular but not exclusive application to a heat pump which permits to obtain a much higher-temperature fluid and to shorten the time taken to make it available.

2. Statement of Related Arts Prevailed hot-water supply heaters include electric heaters and hot-water boilers. Their running costs, however, have been high and especially, the hot water boilers have caused a problem of environmental pollution, due Hence heat pumps as a hot-water supply system that is of a low cost and non-polluting have been noted, and.

recently, being possible to concurrently use as refrigerator, a multitude of heat pumps that permit to isimultaneously supply cold water and hot water have been commercially available.

One example of such known heat pump is illustrated in Fig. 3 in which a compressor a condenser an expansion valve and an evaporator constitute a refrigeration cycle; on the condenser side, a circulation path of water to be heated to a hot-water tank which path has a water 2 pump and a valve interposed is arranged; and on the jvaporator side, a circulation path of water to be coolded to a cold water tank which path has likewise a water pump and a valve interposed is arranged.

The refrigeration cycle of the prior art heat pump thus constructed which is capable of simultaneously supplying cold and hot waters can be represented in a Mollier diagram as shown in Fig. 4, in which the symbold and denote an enthaply value and pressure value, respectively. The Mollier diagram shows the following: in the beginning, in the compressor a refrigerant undergoes pressurization and compression, during which stage an enthalpy change from ii to i 2 occurs; following that, in the condenser the gaseous refrigerant is cooled by the heat exchange with water to be heated and liquefied at constant pressure until it becomes a supercooling state of i 3 then, the liquid refrigerant enters into the expansion valve where it expands adiabatically to result in the state of i 4 which is the same value as i 3 thereafter, in the evaporator the refrigerant absorbs heat by the heat exchange with water to be cooled thereby to be gasified at constant pressure and becomes a superheating y state of ii', which shifts from i i without reverting to the initial value of i i Thus, on the condenser side and the evaporator side, the hot water tank and cold water supply tank are provided, respectively, and water inside the cold-water tank is circulated by means of the water pump (10) to undergo heat exchange with gaseous refrigerant. As a consequence, -4 1 CC C t C C C

CO

I I C the condensation pressure is envn Led, atl onded by an c nvaed condensation tempera ture, so that a high-temperal:ure waper is obtained whereas the evaporat-ion pressure is diminished with concomitant dropping in evaporation temperature, thus producing a cold water. Withli thesie changesof state, the Mollier diagram shifts, with the lapse of operation time, gradually in the ordinate axis direction as shown in the changes of:i- i 1 2 3 i 3 i 4 1i 4 i 4 1 and consequently, a low COP (coefficient of performance) value is obtained.

The COP value of the Mollier diagram illustrated in Fig. 4 can be defined by the equation: (i2 i (COP) (i2 As known well, the COP of a heat pump indicates the degree of thermal efficiency of its system and its magnitude affects the final temperatures of cold and hot waters obtained.

It can be clearly seen from the equat-i above that in order to enhance the COP, it is better to increase (i2 i 3 namely, the enthalpy difference on the condenser side and (i'l-i 4 i.e. the enthalpy difference on the evaporator side and to decrease (i2" i.e. the equivalent of work of the compressor Heretofcre, to that end, many measures have been adopted to enhance the thermal efficiency of a condenser (2) c PC 4 and/or an evaporator for example, by enlarging each heat transfer area, making the enthalpy difference between the supercooling and superheating regions greater by conducting heat exchange between the liquid refrigerant on the outlet side of the condenser and the gaseous refrigerant on the outlet side of the evaporator, etc. As a result, exist- Cr- ing heat pumps supplying simultaneously hot and cold waters exhibit a COP on the order of 4.0 and produce ultimately a hot water of about 0 C 0 i- The foregoing prior art heat pump of the same kind as the invention, however, has a long build-up time (rise time) since water to be heated is circulated by means of the water Uj pump of the hot-water supply tank stated another way, a predetermined hot-water temperature is obtained while regenerating the heat of the condenser in the hot-yxater i 'supply tank and besides, is not capable of producing such a hot water that exceeds 75°C even with the aforementioned measures. According to such circulation system wherein the water to be heated undergoes heating as it circulates, it is impossible to elevate the temperature of water at a time, and when the temperature of water is elevated to a definite temperature with the elapsed time of operation, the logarithmic mean temperature difference between the water and the refrigerant in the condenser becomes slight, and particularly where the logarithmic mean temperature difference is below a definite value, further circulation does not give a heat quantity sufficient to

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exchange and the refrigerant no longer condenses. Thus the temperature rise stops. Consequently, an increased compression ratio and a diminished COP are resulted.

In the status quo as stated above, if a hot water above 750C is intended, then the combined use with the aforesaid electric heater, hot-water boiler, etc. will be indispensable and consequently, the problems of high cost and environmental pollution will be still inevitable.

SUMMARY OF THE INVENTION: According to this invention there is provided a heat pump capable of simultaneously supplying cold and hot fluids which comprises a refrigeration cycle of a 4 0 refrigerant including a compressor, a condenser, expansion valves and an evaporator, said refrigeration cycle having a heat exchanger for causing heat exchange between refrigerant liquid flowing from an outlet of said condenser to said expansion valves and refrigeraat gas flowing from said evaporator to said compressor, said heat exchanger being located midway between a route connecting said condenser and said expansion valves and a route connecting said evaporator and said compressor and serving to subjecting said refrigerant liquid ai.d said refrigerant gas -to heat exchange in countercurrent flow; a once-through path, for a fluid to be heated, connecting from a feed inlet from its fluid source via said j c P condenser to a hot-fluid supply outlet; and a once-through path, for a fluid to be cooled, connecting from a feed inlet from its fluid source via said evaporator to a cold-fluid supply outlet; said condenser being constituted so that said refrigerant and said fluid to be heated may be passed therein in countercurrent flow.

The term "fluid" used herein means mainly water, c but shall not be limited to it, tnd also includes air and other substances. For convenience sake, mention will be 6made hereinbelow of water in place of fluid.

The present invention permit the simultaneous supply of cold and hot waters, but shall not preclude the single use of hot water supply or cold water supply.

Said evaporator and said condenser each may have a heat exchange capacity of more than twice that when a normal refrigeration cycle having a temperature difference between said refrigerant and each fluid of 10 C to 20 C is operated by the use of said compressor.

It is preferred that said evaporator is constituted so that said fluid to be cooled and said refrigerant may pass in parallel flow.

Said evaporator may be constituted so that said fluid to be cooled and said refrigerant may pass in countercurrent flow.

BRIEF DESCRIPTION OF THE DRAWINGS: In order that the present invention might be more fully understood, embodiments of the invention will be described by way of example only with reference to the accompanying drawings in which: Fig. 1 is a schematic system illustration showing i* one example of a heat pump capable of simultaneously I supplying cold and hot fluids pertaining to this an Sembodiment of the invention.

Fig. 2 is a Mollier diagram of the heat pump shown 1 in Fig. 1.

Fig. 3 is a similar system illustration of a prior art heat pump of the same kind.

Fig. 4 is a Mollier diagram of the prior art heat J pump shown in Fig. 3.

Fig. 5 to Fig. 8 are each a graphical representation showing a once-through mode of an embodiment of this invention in comparison with a prior art circulation mode in regard to the hot-water output temperature (condenser side), COP value (condenser side), 7 cold-water output temperature (evaporator side), and COP value (evaporator side), and COP value (evaporator side) against the elapsed operation time, respectively.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION: The once-through mode of an embodiment of the invention is distinct from the known circulation mode in which water to be heated or water to be cooled gains a predetermined temperature while being circulated, and is characterized in that water is routed through the condenser or evaporator, there it gains a predetermined temperature at a time, and in that state, is supplied to a utilization side.

According to a preferred embodiment of a heat pump of this invention, the capacities of the condenser and A evaporator are intensified, preferably to more than twice those of a normal refrigeration cycle having a temperature difference of 10-20 C, so as to permit a sufficient heat exchange for the supply of a higher hot-water or a lower cold-water.

With the heat pump capable of simultaneously supplying cold and hot waters thus constructed in accordance with an embodiment of the invention, because the liquid refrigerant on the outlet side of condenser and the gaseous refrigerant on the outlet side of evaporator undergo heat exchange in countercurrent flow by means of the refrigerant liquid-gas heat exchanger, the liquid refrigerant at a higher temperature already in supercooling state and the gaseous refrigerant at a low temperature in superheating state are caused heat exchange, whereby the 4V liquid refrigerant is cooled and further supercooled whereas the gaseous refrigerant is heated and further superheated.

Prior to this heat exchange, in the condenser, water to be heated is supplied in countercurrent flow to the refrigerant and in a once-through mode, and q I li_ 8 consequently, fresh feed water is always flowed into the condenser, thereby to permit to expedit more efficient supercooling at the outlet side of the refrigerant and to maintain a large logarithmic mean temperature difference between the feed water and refrigerant.

On the other hand, in the evaporator, too, feed water is transferred in a once-through mode, whereby it is possible to maintain a large logarithmic mean temperature difference between the feed water and refrigerant.

In this manner, by expediting the supercooling and superheating in the refrigeration cycle, the enthalpy differences of the condenser side and evaporator side is increased, and by the retention of a large logarithmic mean temperature difference, the compression ratio is I C minimized. As a result of a synergic effect of these, the COP is enhanced and a sufficient heat exchange is attained.

,Hence, in the heap pump pertaining to this invention, water to be heated reaches an elevated temperature in the instant of flowing through the condenser once and is converted to a high-temperature water for the hot-water supply use.

One exemplary embodiment of this invention will be hereinbelow 9 described with reference to Fig. 1, wherein a path of refrigerant is constructed by interconnecting pipings from an outlet side of a compressor 1 through a condenser 2 into a refrigerant liquid-gas heat exchanger 11, past expansion valves 3 and through an evaporator 4, again into the heat exchanger 11 and from there to an inlet side of the compressor ooooo 1, thus constituting a refrigeration cylce.

o 0 00 00 0o a For a path of water to be heated, a once-through path 0 0 O 00 oo0 o0 is constituted by connecting pipings from a feed spout 0 00 oo o0 through the codenser 2 so as to make a countercurrent to the 0000 0 oooo refrigerant path, via a valve 7 to a hot-water supply tank and a hot-water supply spout 12 located in parallel thereto.

For a path of water to be cooled, a once-through path 0000 0 0 000o is constituted by connecting pipings from a feed spout 16 of 0000oooo a 0 0 0 0 0 0 o o fresh water through the evaporator 4 and past a valve 8 to a 0 °oooo° cold-water tank 6 and a supply spout or faucet 13 located in parallel thereto.

o0o0 In the evaporator 4, flows of the refrigerant and water 0 0 oooo to be cooled are constituted as parallel flows in that figure, unlike the case with the condenser 2, but may be constituted as countercurrent flow as is the case with the condenser 2.

For the condenser 2 and the evaporator 4, ones each having a larger capacity than usual are used to achieve thorough condensation and evaporation thereby to meet the intended temperatures of high-temperature water and cold an water to be obtained, and asAexpansion valve 3, one having a large flow rate is used concomitantly so that adiabatic I_ 1_ 10 expansion of a liquid refrigerant may be completely done.

The operation of the heat pump simultaneously supplying cold and hot wa'. thus constructed will be explained on the basis of the Mallier diagram in Fig. 2.

A gasec,,u refrigerant undergoes adiabatic compression with the aid of the compressor 1, during which stage the enthalpy rises from i 1 to i 2 in the next condenser 2 it 0" causes thermal exchange with water to be heated whereby it a is cooled at constant pressure and becomes a liquid refrigeo rant, which is further cooled to a supercooling state of i 3 oo 00oo At this time, since the path of the water to be heated is constituted as a once-through mode as stated above, and the water thermally exchanges with the refrigerant in countercurrent flow thereto, the water to be heated which is always newly fed cools the refrigerant, whereby the logarithmic mean temperature diffe:ence between both is kept at a large constant value and concurrently, the water to be heated flows, at ordinary temperature, into the outlet side of the condenser 2 out of which the refrigerant leaves and causes heat exchange with the refrigerant, thus making the supercooling more efficient.

The liquid refrigerant in the statie of enthalpy i 3 flows to the refrigerant liquid-gas heat exchanger 11, where it is cooled by the gaseous refrigerant from the evaporator 4 whereby the refrigerant already in the supercooling state is further supercooled to the state of i 3 11 Thereafter, by adiabatic expansion in the vpYension valves 3, the refrigerant becomes the state of enthalpy 14'.

The refrigerant is then transferred to the evaporator 4 where it absorbs the latent heat by the heat exchange with water to be cooled, and is converted to gaseous refrigerant at constant pressure and superheated to the state of i i In the evaporator 4, the flow of water to be cooled in a once- '0 through mode permits to maintain a large logarithmic mean #0 a c temperature difference between the gaseous and liquid *0 refrigerants. The gaseous refrigerant again enters into the refrigerant liquid-gas heat exchanger 11, and there, it is heated by the liquid refrigerant from the condenser 2 and its superheating region is further enlarged to the state of enthalpy i i Thus, on the one hand, by retaining always the logarithmic mean temperature difference between the ctndencer side and the evaporator side at a large value, the compression ratio of the compressor 1 is maintained at a small value and, on the other hand, by increasing the enthalpy difference between the supercooling and superheating regions, the enthalpy differences of the condenser side and the evaporator side is enlarged. At this stage, the COP is represented by the equationt (i 2 3 (i i 4 (COP) 0 (i 2 4- i 1 .4 12 The relations hold,~ 3) 2- i 3 i 1 4> 1i. i 4 The difference between (21- il) and (i 2 -il) is slight because for (i 2 1 the compre!'sicn ratio is kept qmall.

From these, 1,t will be apparent that the COP is enhanced, which means in enhanced thermal efficiency. Conspquently, water to be heated is converted, in a short period of time when it flows through the condenser 2, to a high-temperature water, which may be stoz'eO in the hot-water supply tank 5 or can be supplied directly to the supply spout 12 to be offered for use. Likewise, water to be cooled is converted, in a chort period of ti-.me when it flows through the evaporator 4j, to a cold water, which may be stored in the cold water tank 6 or can be supplied directly to the ,iupply spout 13 or use.

The heat pump according to this example was tested of performance8 under the following concitionst Compressor 5 .5 KW Heat-transfer area of condenser Q.42(m 2 /one heat transf~r tu.be) x 2 0.84 m 2 Hea-.-transfer area of evaporator O.55(m 2 /one heat 2 transfer tube) x 2 1.10 m 2 iHeat-transfer area of refrigerant liquwc1-qas heat exchanger 0.15 m2 Refrigerant Fron R~ 12(trade name of dichlorodiflUorome thano) When water to be cooled and water to be heated both at were fed fr~om the respective feud statioto 15,16 and 13 the eompressor 1 was driven, a high temperature water of was made available to the hot-water supply spout 12 tank 5 and a cold water of 6*C was maCe available to the cold-water supply spout 13 or tank 6. The temperature and pressure values were measured at both terminals of each of the condenser 2, evaporator 4 and refrigerant liquid-gas heat ~changer 11, and the enthalpy was calculated. The COP was calculated in acco~rdance with the Mollier diagram shown in Fig.~ 2.

0:0::.Temperature Enthalpy Temperature Enthalpy 6i 0 c 136.9 i 4 45 0 C 143.2 0000 1 S2 10C145.8 i 2 4' 153.8 i87 0 C 122.1 i 3' 65 0 C 115.8 0 3 .1487 OC 122.1 i 65 OC 115.8 =(1,53.8 -122.1) (136.9 -115.8) 153.8 -143.2 This COP value is significantly higher than the convent,4.onaJ value on the order of 4.0, which fact shows that the thermal. efficiency is improved.

Further, comparison was made between the once-through type heat pump of this invention and a con~ventional circulation type heat pump with the hot-water supply output temperiture and COP (both, condenser side) and the cold-water supply output temperature and COP (both, evapora~tor side) versus the elapsed operation time. Resulvts are shown in Table I1 and Table 2 qiven below.

14 These comparative data were also plotted each as a graph and illustrated in Figs. 5, 6, 7 and 8, in which the round mark O represents the once-through type and the square mark (0 the conventional circulation type.

In the measurement, a C-C (copper-constantan) thermocouple thermometer was used for the temperature; a rotameter, for the output quantities of cold and hot waters; a Bourdon tube gage, for the condensed gas pressure and evaporated gas pressure; and a clamper type wattmeter, for the consumed power of the compressor.

With the conventi'nal circulation type heat pump, ca.

lit. of water w.s charged into the hot water tank and ca. 105 lit. of water was charged into the cold-water tank and respective circulation quantities of cold and hot waters were 2500 lit./hr, With the once-through type heat pump, the hot-water output quantity was 180 lit./hr. and the cold-water output quantity was 500 lit./hr.

I- .d 15 Table 1 Elapsed Operation Time vs. Hot-water Supply Output Temperature and COP (Condenser Side) 0000ooooo00 0 oo0 0 0o o 0 0 0 00 0 0 0 0 0 o000 000 0 0 1 i i i

I

Elapsed Operation Time (min.) 0 2 4 6 8 10 12 14 16 18 22 24 26 28 32 34 36 38 Hot-water Supply Temperature( "C) Once-through Type 20.9 54.3 74.4 82.4 84.3 85.1 86.2 86.5 86.8 87.8 88.7 89.5 89.6 89.7 91.3 92.5 94.0 94.8 95.3 96.2 100.0 Circulation Type 19.3 26.9 31.0 34.8 38.7 42.4 46.1 49.8 53.6 56.6 59.6 63.0 65.8 68.6 71.2 73.7 Inoperable because of automatic stopping at high pressure Once-through Type 1.39 2.07 2.34 2.40 2.38 2.45 2.44 2.43 2.47 2.49 2.55 2.53 2.55 2.60 2.61 2.67 2.69 2.68 2.75 2.89 S2.78 2.83 2.36 2.55 2.23 2.12 2.17 2.22 2.04 1.89 2.02 1.86 1.77 1.70 1.56 Inoerable because of automatic stopping at high pressure Circulation Type I- d7 ii 16 Table 2 Elapsed Operation Time Output Temperature and Elapsed Opera- Cold-water Supply tion Time Temperature vs. Cold-water Supply COP (Evaporator Side)

COP

(min.) One-through Type Circulation Type Once-through Circulation Type Type 1 4 ;j i1 17.7 7.2 7.3 6.9 7.2 7.4 7.1 6.4 6.4 5.9 6.4 6.3 6.4 6.3 6.2 19 .6 15.3 13.3 11.0 9.0 6.9 5.1 3.5 Shut-down for the prevention of freezing 1.67 1.67 1.74 1.73 1 70 1.64 1.66 1.69 1.68 1.66 1.72 1.75 1.67 1.73 1.69 1.71 1.76 1.71 1.73 2.16 1.88 1.95 1.75 1.66 1.68 1.33 Shut-down for the prevention of freezing" 1.74 17 As shown in Table 1 above, on the condenser side, with the once-through type heat pump, the water temperature of ca.

0 C was elevated, after 6 minutes, instantaneously to 80 0

C

and upwards and, after 40 minutes, to 100°C. Irrespective of the high rise in hot-water supply temperature, the COP value was stably maintained at high values, with no reduction.

In contrast, in the case of the circulation type heat pump, it is not possible to make a hot water above available and the COP decreases with the rise in hot-water supply temperature. When it was tried to obtain a hot water above 75°C, the condensation pressure of the refrigerant in the condenser became extraordinarily so high (above 30Kg/cm2) that a safety switch for shut-down at high pressure was on and the heat pump was inoperable.

S On the other hand, on the evaporator side, Table 2 above clearly shows that with the once-through type heat pump, the water at 18 0 C is cooled, after 2 minutes, instantaneously to 7 C and thereafter, n cold water on ths order of 6°C was steadily supplied. The COP was maintained steadily at high values with the lapse of operation time.

if However, with the circulation type heat pump, it is possible to lower the supply output tempelature for cold water by forced circulation of water in the cold water tank, but with the dropping in output temperature, the COP value decreased. When the cold-water output temperature reached the operation was stopped to prevent water from freezing in the evaporator.

h ly 18 From the above comparison, it follows that a circulation type heat pump has generally the following defects: In order to obtain a required cold water and a required hot water temperatures, the operation of a long buil-up time orise time) is necessary.

(ii) A hot water having a supply output temperature of or more cannot be obtained.

(iii) The cold water tank and hot water tank are indispensable to feed fresh water therein, to supply and store the circulation water, and for the heat accumulation.

(iv) Thc larger the temperature difference between the hot water or cold water supply output temperature and the initial input water temperature, the more the COP decreases.

The once-through type heat pump adcording to this invention is advantageous in the following points: The rise time for obtaining a required temperature of hot water or cold water is very short and once the rise time is reached, the required hot water or cold water is made available'instantaneously.

A hot water having a supply output temperature of 90°C or more is available.

The cold water tank and hot water tank for storing the once-through water are not essential elements of the heat pump, but may be dispensed with, depending on the intended use.

It is possible to supply cold water and hot water steadily with the lapse of operation time and the COP is maintained stably at high values.

19- Hence the adoption of a once-through type heat pump pursuant to this invention permits to overcome and improve all the defects conventional circulation type heat pumps have had. Moreover, futher high temperature water can be obtained, so that its application or utilization spectrum is wide, bringing significantly large effects.

The foregoing description is made with the embodiment in which hot water and cold water are simultaneously supplied, but according to this invention, it is, of course, possible to supply only either of them.

Thus far described, \the present invention provides a heat pump wherein a refrigerant liquid-gas heat exchanger for conducting the heat exchange between high-temperature liquid refrigerant on the outlet side of the condenser nnd lowtemperature gaseous refrigerant on the outlet side of the evaporator is incorporated in the refrigeration cycle; in the condenser, water to be heated which is fed in once-through mode and the refrigerant undergo the heat exchange in countercUrrent flow and in the evaporator, water to be cooled which is fed in once-through mode and the refrigerant undergo the heat exchange in parallel flow. As a consequence, these combined features produce a synergistic effect, and a conspicuous enhancement in COP is attained.

More specifically stated, the increase in enthalpy difference between the supercooling region and superheating region and securement of the logarithmic mean temperature difference enhance the COP, as a result of which, the hot water output temperature becomes higher;and the once-through mode permnits to supply high-temperature water or cold water in a very short period of time.

The securement of the logarithmic mean temperature difference prevents the compression ratio of the compressor from increasing and consequently, the capacity of the compressor can be made small. Accordingly, the running cost can be further curtailed.

Thus, the heat pump capable of simultaneously supplyo\ eCK'h^ ing cold and hot waters according to this invention allows to obtain such a low-temperature cold water and such a hightemperature hot wat~e that have been heretofore impossible in such an extremely short period of time that has been impossible. For instance, the hot water can be obtained immediately also at the midnight at a cheap midnight charge.

Further, it may be used directly or may be stored in a tank to curtail the electric power.

The heat pump is therefore fitted to the contemporary requirements and tendencies toalow cost and clean energy, having inherently a non-polluting character.

Claims (7)

1. A heat pump capable of simultaneously supplying cold and hot fluido which comprises a refrigeration cycle of a refrigerant including a compressor, a condenser, expansion valves and an evaporator, said refrigeration cycle having a heat exchanger for causing heat exchange between refrigerant liquid flowing from an outlet of said condenser to said expansion valves and refrigerant gas flowing from said evaporator to said compressor, said heat exchanger being CO located midway between a route connecting said condenser and said expansion valves and a route connecting said evaporator and said compressor and serving to subjecting said refrigerant liquid and said refrigerant gas to heat exchange in coutercurrent flow; a once-through path, for a fluid to be heated, connecting from a feed inlet from its fluid source via said condenser to a hot-fluid supply outlet; and a once-through path, for a fluid to be cooled, connect- ing from a feed inlet from its fluid source via said evaporator to a cold-fluid supply outlet; said condenser being constituted so that said refrigerant and said fluid to be heated may be passed therein in countercurrent flow.

2. The heat pump as claimed in claim 1, wherein said evaporator aid said condenser each have a heat exchange caL capacity of more than twic that when a normal refrigeration cycle having a temperature difference between said 22 refrigerant and each fluid of 10tC to 200C is operated by the use of said compressor.

3. The heat pump as claimed in claim 1, wherein said evaporator is constituted so that said fluid to be cooled and said refrigerant may pass in parallel flow.

4. The heap pump as claimed in claim 1, wherein said evaporator is constituted so that said fluid to be cooled and said refrigerant may pass in countercurrent flow.

The heat rump as claimed in claim 1, wherein each of said hot-fluid and cold-fluid supply outlets is a supply spout.

6. The heat pump as claimed in claim 5, wherein each of said hot-fluid and cold-fluid supply outlets further comprises a supply tank disposed in parallel to said suppl, spout.

7. A heat pump substantially as hereinbefore described and illustratd with reference to Figures 1, 2 and 5 to 8 of the accompanying drawings. DATED THIS 1ST DAY OF NOVEMBER, 1990. OSAFA PREFECTURE and NISHIYODO AIR CONDITIONER CO., LTD. By Their Patent Attorneys: GRIFFITH HACK CO. Fellows Institute of Patent Attorneys of Australia.