Method to transfer heat or refrigerant and heat pump for practical application of this method

The invention relates to a method for the transfer of heat or refrigerant between two separate flows of fluid, by means of a heat pump incorporating a refrigeration cycle. The refrigeration cycle comprises an evaporator, a compressor, a condenser and a regulating valve, the evaporator and the condenser being adapted for heat exchange with the two separate fluid flows. During a heating operation, one of the fluid flows, before entering the evaporator, is brought into heat exchange in a first heat exchanger with the refrigeration cycle between the condenser and the regulating valve.

The invention relates to a method to transfer heat or refrigerant within 
two separate flows of fluid with the aid of a heat pump which comprises a 
refrigeration cycle with an evaporator, a condenser and a regulating 
valve, whereby the evaporator and the condenser can accomplish a heat 
exchange with the separate flows of fluid. The invention further relates 
to a heat pump for the carrying out this method. 
Heat pumps of various designs for heating and cooling purposes are known. 
They include a closed refrigeration cycle with a condenser and an 
evaporator. The condenser and the evaporator act as heat exchangers. The 
evaporator removes from its surroundings the heat necessary to vaporize 
the circulating refrigerant. The refrigerant is then compressed in its 
vapor state with the aid of the compressor, and is then liquified in the 
condenser at a higher pressure and temperature level. During this process 
of condensation, the latent heat is released and delivered to the 
surroundings. If, for example, a heat pump is used as a device to heat the 
interior of a building, the evaporator will be located at the outside of 
the building in heat exchange with the surrounding air, with the condenser 
being placed inside the building in heat exchange with the air indoors. 
A heat pump offers the great advantage that the energy required for the 
operation of this pump, for example electrical energy, is not directly 
converted into an output of heat but is used solely to drive the 
compressor, and possibly some auxiliary equipment. If energy is converted 
directly into a heating effect, the ratio of delivered heating performance 
to expended energy can never exceed the coefficient in the case of heat 
pumps, it can be three- or four-fold greater since energy is expended only 
to deliver or "pump" available heat from one location to another. 
Therefore, heat pumps do contribute significantly to the conservation of 
energy, and and will not contaminate the atmosphere with any combustion 
residues, an advantage over standard methods which generate heating energy 
by means of combustion. 
Since heat pumps in air-conditioning installations are normally used for 
cooling as well as heating purposes, the refrigeration cycle will be 
reversible in standard systems. In other words, it must be possible to 
operate the evaporator and the condenser interchangeably as condenser and 
evaporator. A change-over mechanism is therefore needed which will permit 
the selective connection of the discharge, or respectively, the intake 
side of the compressor with either one of the heat exchangers (condenser 
or evaporator). Such changeover mechanism will comprise, in addition to an 
intricate four-way valve, check valves to control the direction of 
circulation, quantity regulators and other complicated governing units for 
the control of the heating or cooling operation. While heat pumps normally 
consist of components which are relatively simple and resistant to 
failure, the above-described change-over mechanism is costly and difficult 
to manufacture, greatly subject to wear and tear as well as malfunctions, 
so that specially trained personnel are needed for manufacture, assembly, 
installation as well as maintenance, making it impossible to mass-produce 
such heat pumps in an inexpensive and simple manner. Known 
air-conditioning units have the additional disadvantage that, for use in 
compact, single housing installations, they require, being designed in a 
compact, a opening in the outer wall of the building, so that one heat 
exchanger can be located on the outside, and the other on the inside of 
the building. Furthermore, since only a limited number of areas in the 
outer wall of a building are suitable for such installation, it will not 
always be possible to select an optimum location for the inside heat 
exchanger. If heat pumps are produced in the form of split aggregates, 
with the heat exchangers placed in separate housings, it becomes necessary 
to assemble the refrigeration cycle system at the place of installation 
and to bridge the span between the two components, which also involves 
careful and complete insulation. Both solutions have the disadvantage that 
the heat exchangers on the inside are at a specific and fixed location and 
will provide a heating or cooling output at this location only, so that it 
will usually be impossible to provide uniform air-conditioning in all 
interior areas. 
It is the object of the invention to provide a method, and a heat pump of 
the above-described type, in which the heat pump can be produced in a 
simple manner and at low cost, and is designed in the form of a compact 
unit which is sturdy, not subject to frequent break-downs, easily 
installed and maintained, and which -as a special feature- is portable and 
can be installed at various locations, operates at a high degree of 
efficiency and adapts to existing conditions to an optimal extent. 
According to the invention, this problem is solved by using the method 
above described characterized in that the refrigeration cycle operates 
steadily and in the same direction, and that the separate flows of fluid 
are brought to heat exchange with the evaporator and the condenser 
interchangeably to attain either heating or cooling operation. 
This specific method makes it feasible to design a heat pump in the form of 
a compact unit without the need of providing a large opening through the 
outer wall. It will now be sufficient to conduct the outside air into the 
interior of a room through pipes or tubes. Such pipes or tubes only 
require wall openings of approximately 10 cm diamater. This method offers 
the particularly important advantage that it makes unnecessary the 
change-over mechanism for the reversal of the refrigeration cycle because 
this cycle will always maintain its direction of rotation. Condenser and 
evaporator will always function as condenser and as evaporator so that 
they can be constructed in an optimum manner in accordance with their 
specific function. In case of the standard, known units the function of 
the heat exchangers will change upon the conversion from heating to 
cooling operation, or vice versa. The switching of the two flows of fluid 
from condenser to evaporator and vice versa, as proposed by the invention, 
can be accomplished constructively by the use of very simple means. The 
assembly of the heat pump proposed by the invention is not complicated and 
does not require specially trained personnel. 
Since the refrigeration cycle is a closed unit which operates in one mode 
always, it can be installed in light-weight, portable housings which can 
be inserted in any desired location. The bridging of the distances 
involved is accomplished with the aid of the two flows of fluid, and not 
with the aid of the tubings of the refrigeration cycle. By a proper and 
varied conduit of the flows of fluid, and possibly by the use of several 
compact and inexpensive heat pumps, it becomes possible to deliver the 
heating or cooling output at various points of a building, or a room 
within the building, as desired. It is also possible, for example, to 
return outside air to the outside and to deliver inside air to the 
interior, and it is also possible, in summer, to cool off the outside air 
by heat exchange with the evaporator and to deliver this air to the 
inside, and to exhaust inside air, drawn from inside. In the latter case 
the air change per hour can be so dimensioned that it amounts to eight 
times of the cubic room capacity, meeting the ventilating requirements for 
public places such as inns. The outside air, or in the latter case the 
inside air, can be removed to the outside also through already existing 
ducts instead of specially arranged conduits. 
If this type of two-way air change is used, it will be particularly 
advantageous at the time of cooling operation, to place the refrigeration 
cycle of the heat pump inside the room to be cooled because the condenser, 
in heat exchange with the used-up inside air, will then be at a 
substantially lower temperature than it would be if it were placed at the 
outside of the building and in heat exchange with the generally warmer 
outside air. As a result thereof, the coolant reaching the evaporator and 
the compressor by way of the regulating valve will likewise have a lower 
temperature, thus improving not only the degree of efficiency of the 
refrigeration cycle overall, but reducing also the power demand on the 
compressor, as will be explained later on in detail. 
The versatility of the heat pump according to the invention makes it 
possible to utilize the heat released during the cooling process at any 
location desired for heating purposes, for example to heat up water in the 
bath room, and to use the refrigerant obtained during the heating process 
for the operation of a refrigerator or the like. 
The heat pump of the invention comprises a refrigeration cycle with an 
evaporator, a compressor and a regulating valve, where the evaporator and 
the condenser can accomplish a heat exchange with separate flows of fluid 
for the transfer of heat or refrigerant from one fluid flow to the other 
fluid flow, and the heat pump is characterized by the features that the 
refrigeration cycle operates steadily and in the same direction for 
heating as well as cooling operations, and that the separate flows of 
fluid are each brought to heat exchange with the evaporator and the 
condenser interchangeably. 
One significant characteristic of the invention, applicable to all heat 
pump species of this application and to any other heat pumps, is the 
extraordinarily advantageous feature that during heating operation the 
fluid flow being guided to the evaporator is brought into heat exchange 
prior to its entry into the evaporator with the refrigeration cycle 
between condenser and regulating valve within the counterflow cooler or 
heat exchanger. It is known in refrigeration installations to cool the 
refrigeration cycle after its passage through the condenser by an 
externally fed coolant. It is also known in such installations to 
accomplish this cooling in the form of a so-called "internal" heat 
exchange, namely, by bringing into heat exchange the refrigeration cycle 
between evaporator and compressor with the refrigeration cycle between 
condenser and regulating valve. The additional cooling produced by this 
step will lower the energy losses caused by the valve effect, and increase 
correspondingly the cooling output delivered to the cold storage space. 
The thermodynamic interrelationships can be proven, but they are known in 
connection with refrigeration installations and are not the subject of the 
invention. 
Contrary to prior art theories, the invention proposes to carry out a 
cooling of the refrigeration cycle between condenser and regulating valve 
especially during heating operations. Contrary to known processes, the 
principal aim is not to increase the cooling performance of the 
evaporator, because this refrigerant is utilized at best as a by-product 
only. It was found, rather that such cooling of the refrigeration cycle 
will result in three extraordinarily important advantages, and especially 
during heating operations, as will be explained here in detail: 
1. The fluid conveyed from outside the building and brought into heat 
exchange with the refrigeration cycle is heated during the course of the 
heat exchange in accordance with the rate of flow, thus making it feasible 
to utilize in the heat exchanger, which includes the evaporator, a greater 
temperature difference between the fluid conveyed from the outside and the 
fluid returned to the outside. This has the same effect as an increase in 
the outside temperature, and obviously results in the improvement of the 
efficiency of the heat pump. It is especially important that the heat 
generated by the cooling of the refrigeration cycle can be utilized 
directly and with positive results within the system. 
2. By lowering the temperature of the coolant upstream of the regulating 
valve, and thus upsteam of the evaporator, the thermo-dynamic 
effectiveness or "pump effect" of the heat pump can be significantly 
improved, as shown by the following example: 
Assuming a temperature of 5.degree. C for the fluid conveyed from outside, 
and reduced to 0.degree. C after heat exchange with the evaporator, so 
that the refrigeration cycle will have a temperature of approximately 
0.degree. C upon leaving the evaporator. It is further assumed that the 
coolant after leaving the condenser has a temperature of 50.degree. C 
which will remain at this value across the regulating valve up to the 
evaporator. Under these conditions the following heat content values, will 
apply using as example the standard coolant CC1.sub.2 F.sub.2 ("Frigen 12" 
produced by the Hoechst AG): 
Upstream of the evaporator (50.degree. C, in liquid form): 111.70 kcal/kg 
Downstream of the evaporator (0.degree. C, in gaseous form): 136.43 
kcal/kg. 
The difference, a measure of the heat transferred in the evaporator from 
the fluid flow to the refrigeration cycle, amounts to 24.73 kcal/kg. 
If the fluid, conveyed from the outside of the building at 5.degree. C, is 
now brought into heat exchange with the refrigeration cycle between 
condenser and regulating valve, and the temperature of the coolant is 
lowered from 50.degree. C to 5.degree. C, the heat content value of the 
coolant upstream of the evaporator will be: in front of the evaporator 
(5.degree. C, in liquid state): 101.11 kcal/kg. The difference of this 
value from the heat content value of the coolant downstream of the 
evaporator will now be 35.32 kcal/kg (as against 24.73 kcal/kg, the value 
attained without the use of the counterflow cooling proposed by the 
invention). This is an increase in heat content difference for the two 
sides of the evaporator of approximately 43% in case of the example given, 
which can easily be generalized to show the applicable principle. The 
quantity of heat extracted from the ambient all and delivered as heating 
output increases correspondingly. 
3. The lowering of the temperature upstream of the evaporator will also 
decrease the temperature downstream of the evaporator, thereby lowering 
also the specific volume v of the coolant to be compressed by the 
compressor. The work to be performed by a compressor can be expressed if 
mechanical losses and the like are disregarded by the formula w = .intg.v 
dp. This work is therefore reduced when the specific volume v becomes a 
lower value. 
This is a third important result of the above-mentioned counterflow cooling 
of the refrigeration cycle. 
The three advantages are particularly notable because they can be attained 
without additional use of energy, "free of charge", so to speak. 
Liquid fluid flows are especially suitable for the above-discussed 
counterflow cooling, but it is obviously also possible when the fluid flow 
consists of air. 
The water contained in an existing hot-water heating system can be utilized 
as one of the fluid flows, thus making unnecessary the installation of a 
separate piping system inside a building. 
In buildings provided with appropriate measuring devices at individual 
cooling units to measure the cooling output being used, and which during 
the summer months the cooling output being furnished is utilized for the 
production of hot water, the measured cooling output can be used as a 
basis for the allotment of hot water, thus making unnecessary a separate 
determination of hot water consumption. 
The above-mentioned embodiments can be further varied to facilitate heat 
transfer between flows of fluid in the gaseous and/or liquid state. In any 
event, the refrigeratian cycle will remain constant and unchangeable, 
while control of the heating or cooling operation is accomplished by 
conducting the flows of fluid interchangeably through the condenser or the 
evaporator. In addition to this basic characteristic, the invention 
proposes as another significant feature a pipe system within a building 
which includes either a heat exchanger at the outside of the building, 
where heat pumps can be connected at various locations inside the 
building, or which starts out with a heat pump and permits the connection 
of heat exchangers at various locations inside the building. The latter 
feature represents a characteristic of independent significance.

FIGS. 1 and 2 illustrate a heat pump for summer or cooling operation and 
for winter or heating operation. The refrigeration cycle of this heat pump 
comprises an evaporator 1, a compressor 2, a condenser 3 and a regulating 
valve 4 which are connected by way of pipes 5, 6, 7, and 8 (shown in 
double lines) to form a circulating system. The direction of circulation 
within this refrigeration cycle is denoted by arrows 9. A comparison 
between FIGS. 1 and 2 demonstrates that the direction of circulation 
within the refrigeration cycle does not change upon change-over from 
summer to winter operation but always remains the same, so that the 
evaporator always functions as an evaporator, and the condenser as a 
condenser. A coolant, such as "Fregen", circulates within the 
refrigeration cycle, which is vaporized in the evaporator 1, thereby 
extracting heat from the surrounding area, and upon compression by the 
compressor 2 is then liquefied in the condenser 3, delivering heat to the 
surrounding area. The evaporator 1 and the condenser 3 are components of 
heat exchangers 10, 11 which are designed in the form of two 
interconnected boxes, provided with side by-side in- and outlets 12, 13 
and 14, 15, respectively. The air entering through inlets 12, 14 flows 
within a first chamber 16 or 18, respectively, over the evaporator 1, or 
condenser 3, which will result in a heat exchange. The air is then 
deflected by blowers 20, 21 in U-form and reaches the outlets 13, 15 
through a second chamber 17, 19. 
The air channeled through the heat exchangers 10, 11 forms two separate 
flows of fluid, one taken from the air outside the building, and the other 
taken from the air inside the building. The outside air is denoted by 
arrows 22 with broken lines, and the inside air by arrows 23 with 
continuous lines. 
The switch-over from cooling to heating operation is accomplished according 
to the invention by connecting the outside air is connected selectively 
for heat exchange with the heat exchanger 11 (condenser 3) or 10 
(evaporator 1), while the inside air enters into heat exchange with the 
other, remaining heat exchanger 10, 11. A distributor box , shown in FIG. 
3, is provided for this purpose. 
FIG. 3 shows a heat pump in accordance with FIGS. 1 and 2, in the position 
shown in FIG. 2 (heating operation). The heat exchangers 10, 11 with the 
refrigeration cycle 1, 2, 3, 4 are placed in a box-shaped housing 24. The 
housing 24 is divided in its longitudinal center plane by a wall 25, with 
the heat exchangers 10, 11 located on one side each. Parallel to, and at a 
distance from, both sides of wall 25 are additional walls 26, 27 which 
terminate at a distance from the bottom 28 of the housing 24 and which 
form the chambers 16, 17, 18, 19 as shown by FIGS. 1 and 2. 
The inlets and outlets 12, 13, 14, 15 of the heat exchangers 10, 11 are 
arranged within the upper wall 29 in the form of longitudinal slots, with 
the slots placed in parallel side-by-side. 
At the upper wall 29 of the housing 24 is a distributor box 30 which can be 
moved as indicated by arrow 31. This distributor box 30 is guided on wall 
29 (in a manner not illustrated in detail) and covers in its terminal 
positions either the slot pairs 12, 13 or 14, 15, leaving free in each 
case the other slot pair. The distributor box 30 is open downwardly in the 
direction of the slots, and is provided with an inlet 33 within a wall 32 
and near its lower edge, and with an outlet 34 near the upper edge of wall 
32, the inlet and outlet being connected to tubes 35, 36 or the like. 
These tubes 35, 36 are in communication with the outside of the building 
(not shown). 
At the inside of the distributor box 30 there is an L-shaped dividing wall 
37 which extends throughout the entire length of the distributor box 30. 
The wall 37 has a vertical side 38 which extends within the lower portion 
of the distributor box at its longitudinal center line, and a horizontal 
side 39 which begins at the former and which is connected to the wall 32. 
In this manner communication is established between the inlet 33 of the 
distributor box 30 and the inlet 12 of the heat exchanger 10, as well as 
between the outlet 13 of the heat exchanger 10 and the outlet 34 of the 
distributor box 30. 
FIG. 3 shows that the inlet 14 and the outlet 15 of the heat exchanger 11 
are not covered up by the distributor box 30, so that the inside air can 
be circulated by the heat exchanger 11. The outer air, being in heat 
exchange with the evaporator 1, will be relatively cooled, while the 
inside air, being in heat exchange with the condenser 3, will be 
relatively heated. 
While the flows of fluid which are brought into heat exchange with the 
condenser and the evaporator of the refrigeration cycle are formed by the 
outside air and by the inside air of a building in the embodiment 
illustrated by FIGS. 1 to 3, embodiment of FIGS. 4 and 5 provides for 
flows of fluid in the form of liquid-circulating systems which will 
circulate for example a hydrous salt solution (brine). In the embodiment 
of FIGS. 4 and 5, this brine in turn is in heat exchange with the outside 
air and the inside air of the building by means of heat exchangers. 
The embodiment of FIGS. 4 and 5 does provide a refrigeration cycle, 
comprising an evaporator 41, a compressor 42, a condenser 43 and a 
regulating valve 44, as well as pipe lines 45, 46, 47 and 48 which connect 
the units in such manner that they form a circulating system. The 
direction of circulation is indicated by arrows 49 (FIG. 4). 
Again, the evaporator 41 and the condenser 43 are components of the heat 
exchangers 50 and 51, indicated in FIGS. 4 and 5 by inner tubes 52, 53, 
holding the coolant, and concentric outer tubes 54, 55, holding the 
circulating liquid or brine. Either liquid-circulating system one system 
containing a heat exchanger at the outside of the building, and the other 
an heat exchanger at the inside of the building can be switched into 
heat-exchange contact with the heat exchangers 50, 51 as desired. 
The heat exchanger outside the building is shown schematically at the upper 
portion of FIGS. 4 and 5 and is denoted by numeral 56. This heat exchanger 
is equipped with a fan 57, has an inlet, denoted by, denoted by C and an 
outlet B, with the direction of flow being shown by arrows. The 
liquid-circulating system within the building includes pipes 58, 59, which 
can be installed for example behind the base boards. The tube 58 has an 
inlet D, and the tube 59 has an outlet A, with the direction of flow again 
indicated by arrows. The pipes 58, 59 are closed off at their ends 60, 61. 
They are equipped at various points with plug junctions (not shown) for 
coupling with inlet tubes 62, 63, 64 and outlet tubes 65, 66 67 of the 
heat exchangers 68, 69, 70. The heat exchangers 68, 69, 70 are equipped 
with fans 71, 72, 73 and can be connected with the pipes 58, 59 at various 
points inside the building to facilitate the most efficient distribution 
of heat or refrigerant, especially if larger rooms are involved. 
A change-over valve 74 is used to bring the just-discussed circulating 
systems selectively in contact with the heat exchanger 50 or 51. The inlet 
pipe 75 of the heat exchanger 50 has two branches, one denoted by A, and 
the other by B. Branch A is in communication with the outlet A of pipe 59, 
and branch B with the outlet B of the heat exchanger 56. The change-over 
valve 74 is designed in such manner that one of the branches A, B is 
always open, and the other closed. This applies correspondingly to the 
outlet pipe 76 of the heat exchanger 50 which leads into the branch pipes 
denoted by D and C, which in turn are in communication with the inlet D of 
tube 58 and inlet C of the heat exchanger 56. The change-over valve 54 
simultaneously controls the inlet 77 and the outlet 78 of the other heat 
exchanger 51: for example, if at heat exchanger 50 the branch A is open 
and the branch B is closed, branch A will be closed and branch B will be 
open at heat exchanger 51. This automatically assures that the tubes 58, 
59 are in any given case in communication with one of heat exchangers 50, 
51, and heat exchanger 56 with the other of heat exchangers 50, 51. 
FIG. 4 shows the pipes 58, 59 in heat exchange with the evaporator 41, thus 
cooling the liquid within the pipes, and consequently also cooling the 
interior of the building. The heat exchanger 56 outside the building is 
connected with the condenser 43. In other words, this figure illustrates 
the summer operation, with FIG. 5 showing the corresponding winter 
operation. 
The embodiment illustrated by FIGS. 6 and 7 is a combination of the first 
two embodiments described above, to the extent that one of the fluid flows 
is formed by a liquid-circulating system, and the other by the inside air 
of a room. Again, a constant refrigeration cycle is provided with an 
evaporator 81, a compressor 82, a condenser 83 and a regulating valve 84, 
connected with each other by pipe lines 85, 86, 87 and 88 to form a 
circulating system. The arrows 89 indicate the direction of circulation 
within the refrigeration cycle. The evaporator 81 and the condenser 83 are 
designed as heat exchangers 90, 91, facilitating heat exchange with the 
liquid-circulating system as well as with the inside air of the room. They 
comprise an inner pipe 92 and 93 to hold the coolant, an outer pipe 94, 
95, surrounding the latter concentrically, and a reflecting housing 96, 
97, for example of aluminum, surrounding the outer pipe. The 
liquid-circulating system contains a heat exchanger 98 with a fan 99, 
located at the outside of a building. The heat exchanger 98 is connected 
by means of an outlet pipe 100 and an inlet pipe 101, the latter being 
equipped with a pump 102. The outlet pipe 100 and the inlet pipe 101 each 
end in two branches, one of which always communicates with the outer pipe 
94, 95 of the heat exchanger 90, 91. A change-over valve 103, which is 
almost identical with the change-over valve 74 shown in FIGS. 4 and 5, 
blocks one of the branches of outlet pipe 100 and of inlet pipe 101 while 
opening the other branch, so that the outlet pipe 100 and the inlet pipe 
101 are both connected either with the heat exchanger 90 or the heat 
exchanger 91 but are blocked off from the other heat exchanger, as the 
case may be. A blower 104 draws in the air inside a building, directing 
its flow, in accordance with the position of a flap 105, against 
reflecting housing 96, 97 of that heat exchanger 90, 91 which is not 
subjected to the flow of the liquid-circulating system. The direction of 
flow of the inside air is indicated by the arrows 106. FIG. 6 shows the 
system in cooling position, while FIG. 7 illustrates the heating 
operation. This system provides a particularly simple heat pump, and the 
heat exchanger 98 at the outside of the building can be so dimensioned 
that it can be combined with two or more heat pumps. 
FIG. 8 shows a heat pump with an evaporator 111, a compressor 112, a 
condenser 113 and a regulating valve 114, connected by pipe lines 115, 
116, 117, 118 to form a refrigeration cycle, with the direction of 
circulation indicated by the arrows 19. The condenser 113 is equipped with 
a fan 120. At least the condenser 113, or even the entire heat pump are 
placed at the outside of a building, and the condenser 113 will be in heat 
exchange with the outside air. The evaporator 111 forms a heat exchanger 
and includes an inner piipe 121 and an outer pipe 122 surrounding the 
latter concentrically. The inner pipe 121 hold the coolant, and the outer 
pipe a liquid (brine) which enters the outer pipe by way of an inlet pipe 
123 and leaves it through an outlet pipe 124. A pump 125 is placed within 
the outlet pipe 124. The inlet pipe 123 and the outlet pipe 124 are 
connected to two pipes 126, 127 which are installed inside a building in 
the form of a pipe system, this system extending throughout the building 
as desired, with the ends 128 and 129 closed off. It is possible, as 
explained above in connection with FIGS. 4 and 5, to connect the inlet 
pipes 130, 131 and 132 and the outlet pipes 133, 134, 135 of heat 
exchangers 136, 137 and 138, to these pipes 126, 127 of selected locations 
by suitable sockets (not shown), thereby completing and closing the 
circulating system. In this manner it is feasible to air-condition 
selected areas of a building as desired. The heat exchangers 136, 137 and 
138 are equipped with fans 139, 140 and 141 to circulate the inside air as 
shown by arrows. 
While the heat pump shown in FIG. 8 is only in the form of a cooling 
system, it can, like the other embodiments, also be provided with a 
change-over device for summer or winter operations. The pipe system 126, 
127 with the heat exchangers 136, 137, 138 which can be connected as 
desired, can be employed advantageously for pure cooling or heating 
installations also. 
FIG. 9 shows the principle of FIG. 8 in reverse. While in FIG. 8 the heat 
pump is arranged at the outside of the building and is connected, for the 
purpose of air-conditioning the inside of the building, by way of a 
liquid-circulating system with heat exchangers located inside the 
building, FIG. 9 shows a heat exchanger 142 which is located at the 
outside of a building, with two or three heat pumps arranged inside the 
building. The heat exchanger 142 is equipped with a fan 143. The heat 
exchanger 142 is connected by way of outlet pipe 144 and inlet pipe 145 
with pipes 146, 147 which form a pipe system that can be installed 
throughout the building as desired, for example behind the base boards, as 
described in connection with FIG. 8. The pipes 146, 147 are again closed 
off at their ends 148, 149. Heat pumps can be coupled to the pipes 146, 
147, as will be explained below. The two heat pumps illustrated in FIG. 9, 
are identical, so that only the left hand pumps will be described in 
detail. There is no limit to the number of such heat pumps which can be 
connected to the pipes 146, 147 at various locations. 
The heat pump 150 comprises an evaporator 151, a compressor 152, a 
condenser 153 and a regulating valve 154, and these units are connected by 
pipe lines 155, 156, 157, 158 to form a closed refrigeration cycle, with 
the direction of circulation indicated by arrow 159. 
In this example evaporator 151 is designed as heat exchanger, equipped with 
a fan 160, and in heat exchange with the inside air of the building. The 
condenser 153 is a heat exchanger with one inner pipe 161 and one outer 
pipe 162. The inner pipe 161 holds, the coolant previously described, 
while the outer pipe 162 is connected with the pipes 146, 147 by way of an 
inlet pipe 163 and an outlet pipe 164. A pump 165 is located within the 
outlet pipe 164. In this embodiment, the liquid (brine) cooled in the heat 
exchanger 142 is utilized to liquefy the coolant in the condenser 153. The 
coolant is then varpoized again in the evaporator 151 to cool the air 
inside the building. Here again, as in case of the embodiments shown in 
FIGS. 4, 5 and 8, it becomes possible to place and connect small, compact 
heating and cooling units at any desired location within a building, a 
particularly advantageous feature of the invention. This results in an 
outstandingly advantageous distribution of small quantities of heat or 
refrigerant, a system which is much healthier and results in a more 
uniform temperature distribution than any central air conditioning 
installation. 
The embodiments shown in FIG. 9 can also be used as heating system, namely 
by reversing the heat exchange of the two flows of fluid 
(liquid-circulating system and inside air of the room) with the evaporator 
and the condenser. 
The embodiments shown in FIGS. 10 to 12 differs from the arrangements 
described above primarily in that here the flows of fluid do not form 
fully closed circulating systems, or at least return to their original 
place of removal (outside air to outside air, inside air to inside air) 
but rather become transposed under cetain conditions. Otherwise, the 
design of the embodiment of FIGS. 10 to 12 is generally identical with 
that of FIGS. 1 to 3. The heat pump comprises a refrigeration cycle with 
an evaporator 171, a compressor 172, a condenser 173 and a regulating 
valve 174, where the coolant circulates through the pipe lines 176, 177, 
178 and 179 always in one direction as indicated by the arrow 175. The 
evaporator 171 and the condenser 173 are located in the heat exchangers 
180 and 181. The heat exchanger 180 is substantially identical with the 
heat exchanger 10 shown in FIGS. 1 and 2. A blower 182 is used to 
circulate air in the manner indicated by broken-line arrows 183. The 
outlet 184 and the inlet 185 of the heat exchanger 180, as well as the 
outlet 186 of the adjacent heat exchanger 181, are again located 
side-by-side in the form of parallel slots, while the inlet 187 of the 
heat exchanger 181 has a different location, namely opposite to the outlet 
186. A blower 188 circulates air through the heat exchanger 181. A 
distributor box 189 can be moved across the outlet 184, the inlet 185 and 
the outlet 186 to two terminal positions, at which is will cover either 
outlet and inlet of the heat exchanger 180 (as in FIG. 11), or the inlet 
of the heat exchanger 180 and the outlet of the heat exchanger 181. Box 
189 comprises two separate chambers which are in communication with the 
outside air by way of tubes 190, 191. In this embodiment, the position of 
the distributor box 189 as shown in FIG. 11 corresponds to the position of 
the distributor box 30 as shown in FIG. 2, and there are therefore no 
differences between the two arrangements. However, in the position 
illustrated by FIG. 10, stale inside air is withdrawn in the direction of 
arrow 192 and moved to the exterior by way of the heat exchanger 181 and 
the distributor box 189, while fresh air is drawn in from outside by way 
of the distributor box 189 and the heat exchanger 180, and is cooled and 
delivered into the room in the direction indicated by the arrow 183. This 
embodiment thus permits ventilation of the interior of a building during 
summer operation as shown in FIG. 10. As already mentioned, the volume of 
air being circulated for cooling purposes is also sufficient to meet the 
ventilation standards for public places and the like. 
FIG. 12 shows the heat pump of FIGS. 10 and 11 in a partly sectioned plan. 
A box-shaped housing 193 has in its front wall three slots, arranged 
parallel and side-by-side, representing the outlet 184, the inlet 185 and 
the outlet 186. The distributor box 189 is movably arranged in front of 
these slots within guides 194 (not shown in detail). FIG. 12 shows the 
distributor box 189 in its position above the outlet 184 and the inlet 185 
of the heat exchanger 180 which contains the evaporator 171 and which 
cools the air flowing through it. In the position shown, the unit is set 
for winter- or heating operation. The air is drawn in from the room 
through the inlet 187, shown at the side of the box, and returned through 
the outlet 186. The distributor box is partialy opened up in the drawing, 
and the dividing wall 195 is also cut away in part in order to show the 
outlet 185. This embodiment of the invention is not only extraordinarily 
simple and compact in its construction but also permits in addition of the 
heating or cooling, ventilation by use of fresh air during summer 
operation. 
It will be expedient to provide the compressor in the heat exchanger which 
contains the condenser because it then becomes possible to dispose of, 
and; if appropriate, to utilize the specific heat of the compressor, as 
illustrated in FIGS. 10 and 11. The heat pump of the invention can be 
controlled in a very simple manner by placing into the inlet 185 for the 
outside air a thermostat not shown in FIGS. 10 and 11, to influence an 
injection valve which is arranged downstream of the evaporator and which 
takes over the function of the regulating valve. 
FIG. 13 shows in enlarged scale a portion of FIGS. 4 and 5, namely the area 
of the heat pump. 
The refrigeration cycle 41, 42, 43, 44 again runs continuously and in one 
direction, and the flows of fluid are in contact by way of the inlet and 
outlet pipes 75, 76 and 77, 78 with the heat exchangers 50 and 51 which 
contain the evaporator 41 and the condenser 43 of the refrigeration cycle. 
Any further details can be found in FIGS. 4 and 5. 
FIG. 13 shows, in addition to the arrangement shown in FIGS. 4 and 5, a 
heat exchanger 200 in the inlet pipe line 75 of the heat exchanger 50. 
This heat exchanger 200 is utilized only for winter operation (FIG. 5). It 
is used to heat the liquid drawn in through the inlet pipe 75 of the heat 
exchanger 56 at the outside of the building, with the aid of household 
waste water which is circulated through the pipes 201 and 202. The 
temperature of household waste water will, at least during normal winter 
operation, be higher than the outside temperature, which is also the 
temperature of the liquid drawn in by the inlet pipe 75. If this liquid is 
pre-heated by household waste water, the difference in temperature to be 
overcome within the refrigeration cycle will be reduced in magnitude, and 
the thermal efficiency of the cycle will be improved. 
FIG. 13 further shows a supplemental heating system which can be activated 
in case of extremely low outside temperatures. It is possible for example 
to set and control the supplemental heat in such a manner that 95% of the 
heating output is provided by the heat pump, with the remaining 5% being 
supplied by the supplemental heating system. The supplemental heating can 
take the form of a simple electric heating coil (not shown) within the 
heat exchanger 51. FIG. 13 shows a supplemental heating device in the form 
of a burner 203 which can be an already existing or a specially installed 
oil burner, or a gas burner, coke burner or the like. 
In the example shown, there an additional heat exchanger 204, provided with 
an inner tube 205 and an outer tube 206 is installed in the refrigeration 
cycle, parallel to the heat exchanger 51. The inner pipe 205 holds the 
coolant, and the outer pipe 206 is in communication with the pipes 234, 
235 which carry water supply for a household, while the heating water is 
circulated in the pipes 77 and 78. Pipes 78 and 235, emerging from the 
heat exchangers 51 and 204, are equipped with valves 236 and 237 which 
make it possible to circulate the heating water and the household water 
completely or in part by way of pipes 238, 239, 240 and 241 and the burner 
203, and return the water to pipes 78, 235 for additional heating. 
FIG. 14 is also based on the arrangement shown by FIGS. 4 and 5, and 
illustrates a portion of the refrigeration cycle 41, 42, 43, 44. The 
system is shown as a heating operation. Pipe 47 is surrounded between the 
condenser 43 and the regulating valve 44 by a heat exchanger or 
counterflow cooler 207, with the inlet pipe 75 of the heat exchanger 50 
passing in counterflow through the cooler. This counterflow cooler 207 has 
the effect that the liquid which is present in the pipe 75 and which is 
being conducted from the exterior of the building is heated, and that the 
coolant of the refrigeration cycle is cooled between the condenser and the 
regulating valve. This cooling of the coolant between condenser and 
regulating valve, used heretofore only in connection with refrigerators 
for the purpose of increasing the cooling output of the evaporator, has 
been found to be extremely advantageous within the framework of the 
invention also, and especially, during the heating operation of the heat 
pump. The advantages of this specific solution have already been discussed 
in detail. 
A further improvement of the heat pump can be obtained by bringing conduit 
76 leaving heat exchanger 50 into heat exchange with the refrigeration 
cycle between counterflow cooler 207 and regulating valve 44. The 
temperature of the coolant is thereby further reduced upstream of 
evaporator 41, so that the aforementioned advantages are obtained, and the 
fluid in conduit 46 is heated, so that a smaller heat exchanger 56 (FIGS. 
4 and 5) can be used on the exterior. 
FIG. 15 again shows the refrigeration cycle of FIGS. 4 and 5 and 
demonstrates two possibilities for the utilization of the refrigerant or 
the heat which becomes available during the heating or cooling of a room. 
During the cooling operation (FIG. 4), liquid from the heat exchanger 56 
is located at the outside of the building is drawn up through the inlet 
pipe 77, and upon its passage through the heat exchanger 51 is then 
returned to the outside by the outlet pipe 78 at higher temperature. This 
increase in temperature, a by-product of the cooling process, can be 
utilized, for example in heating water used for household use. FIG. 15 
shows schematically a hot water preparer 208 which can be used for this 
purpose. It represents in principle a heat exchanger similar to the heat 
exchanger 51 in the refrigeration cycle, and it is incorporated into the 
cycle in parallel to the exchanger 51 by way of pipe sections 209, 210. It 
comprises, for example, an inner pipe 211, interconnected with the 
refrigeration cycle, and an outer pipe 212, concentrically surrounding the 
inner pipe, carrying warm household water. Two pipes 213 and 214 are in 
communication with the outer pipe 212 and serve to deliver and to return 
the household water to be heated. A valve 215 in the refrigeration system 
permits the coolant to run selectively either through the heat exchanger 
51, or through the hot water preparer 208, or through both in pro rata 
distribution. 
At the left side of FIG. 15 an additional heat exchanger 216 is shown, 
which is incorporated into the refrigeraton cycle in parallel with the 
heat exchanger 50 and its evaporator and which can be activated 
selectively by means of a valve 217. This heat exchanger 216 which, like 
the heat exchanger 50, extracts heat from its surroundings by the 
vaporization of the coolant, can be utilized to cool during heating 
operation by the heat pump a fluid which is being supplied and then 
removed by way of pipes 218 and 219, thus utilizing this heat exchanger 
216 as a cooling unit. 
FIG. 16 shows an embodiment of a switch-over valve 74 as used in FIGS. 4 
and 5 which permits a switching of the two flows of fluid which are to be 
placed alternatively in contact with the heat exchangers 50, 51. The 
switch-over valve 74 comprises an extended rectangular or cylindrical 
housing 220 with an axial bore 221 which extends through the entire 
housing. The housing 220 is entered by bores 222 and 223, each set of 
bores entering from diametrically opposite sides, and which are connected 
as shown in FIGS. 4 and 5 at one side to the inlets or outlets A, B, C, D, 
and at the other side to the branches of the pipe lines 75, 76, 77, 78. 
Within the axial bore 221 of the housing 220 there is placed an axially 
movable slide bar 224 which is provided with cylindrical sections 225, 
226, 227, 228 which fit closely into the axial bore 221 and which are at a 
distance from each other that equals twice the distance between two bores 
222, 223. These cylindrical sections 225 to 228 are interconnected by a 
thinner shaft 229 to form one single unit. The cylindrical sections 225 to 
228 will block the passage for every other pair of the diametrically 
opposed bores 222, 223 while allowing a communication between the pairs of 
bores located next to the blocked pairs, so that, in the example shown, 
there are always four pairs of bores unobstructed and four pairs blocked. 
The position shown in FIG. 16 corresponds to that shown in FIG. 5, i.e., 
the heating group of bore pairs will be blocked. At the ends of housing 
220, there are placed the covers 230, 231 with the gaskets 232, 233 are 
provided in a manner not illustrated in detail. 
The flows of liquids which are utilized primarily in the embodiments of the 
invention for the transfer of heat or refrigerant from the outside air to 
the heat pump, or from the heat pump to the place of use, offer the 
advantage, in comparison with the direct utilization of outside air and 
inside air as the two fluids being brought into heat exchange with the 
heat pump, that in contrast to our-carrying systems, there is no danger of 
freezing within the pipe systems of these liquids.