[0001] The present invention relates to an apparatus for influencing the temperature in
a building and a method for operating an apparatus for influencing the temperature
in a building comprising a central heat pump unit with a condenser, an evaporator,
a compressor, a heat exchanger and an electronic control unit, which operates the
flow of a refrigerant within a refrigerant piping for the refrigerant inside of the
central heat pump unit, the central heat pump unit being connected to a piping for
distributing liquid through the building from the central heat pump unit to at least
one indoor unit and back.
[0002] From
EP 1 347 253 A1 an apparatus and a method for influencing the temperature in a building is known.
The advantage of this apparatus and method is that a refrigerant is replaced by water
in a single two pipe ring. This replacement is environmentally friendly, as the refrigerants
are causing substantial problems to the atmosphere. Also the safe technical handling
of the refrigerants in a building requires substantial efforts during installation
and use. The water in the ring pipe is capable to balance different heating and cooling
requirements between different rooms in a building at least partially, so that the
energy consumption for operating the air condition in a building is reduced. By adding
a central heat pump unit to the system the temperature of the water in the ring pipe
can be raised or lowered by this heat pump, as it is required. So if there is a general
heat energy requirement, this can at least partially be added to the water in the
ring pipe by the central heat pump unit, and this works respectively with a general
cooling requirement.
[0003] With the known system the individual adjustment of the temperature in a room is achieved
by an individual indoor heat pump unit which is installed in each respective room
and which is coupled to the ring pipe for extracting water from the ring pipe, adding
energy to or taking energy from the water and feeding the water back into the ring
pipe thus heating and/or cooling the room installed individually. The indoor heat
pump unit, however, requires at least some energy for operation, which reduces the
energy efficiency of the whole system, the indoor heat pump unit generates an operational
sound in the room by the compressor of the heat pump, and each individual indoor heat
pump unit is quite heavy and expensive, so that in a bigger building the weight of
the system and its costs are quite substantial. There is also still a refrigerant
used in each indoor heat pump unit, which increases the technical complexity of the
individual heat pump unit and its service requirement.
[0004] Currently there are also 3-pipe fan coil systems on the market. These systems, however,
are operating with a refrigerant in the pipes. This means that in one pipe there is
a hot gas high pressure refrigerant directly from the compressor, in the second pipe
there is a liquid refrigerant condensed, and in the third pipe there is a cold gas
low pressure coming from the evaporator. The refrigerant used throughout the building
is becoming more and more environmentally critical. The high pressure pipes are difficult
to mount, there are quite often leaks with refrigerant dropping into the building,
and repairs are expensive. The indoor units can be used for both, heating and cooling.
[0005] There are also 4-pipe-systems which deliver warm water with 40° to 55° C, cold water
with 5° to 10 ° C and warm water returns of 35° - 50° C. These systems are also energetically
ineffective as the temperature difference between the temperatures of the liquid in
the pipes and the average temperature in the building is quite high and the energy
losses are high.
[0006] It is the subject of this invention that the disadvantages mentioned above are at
least reduced to some extent.
[0007] This problem is solved by an apparatus, which comprises:
- a central heat pump unit with a warm liquid outlet to a warm liquid piping, a cold
liquid outlet to a cold liquid piping and a liquid inlet connected with a return liquid
piping (42),
- a condenser as a part of the central heat pump unit being connected with the warm
liquid outlet and the liquid inlet,
- an evaporator as a part of the central heat pump unit being connected with the cold
liquid outlet and the liquid inlet,
- a compressor as a part of the central heat pump unit to pressurize a refrigerant,
- a heat exchanger as a part of the central heat pump unit to evaporate and heat or
to condensate and cool the refrigerant,
- a refrigerant piping as a part of the central heat pump unit being connected with
the condenser, the evaporator, the compressor and the heat exchanger, which distributes
the refrigerant in the central heat pump unit, and
- at least one indoor unit being connected with the warm liquid outlet by the warm liquid
piping, the cold liquid outlet by the cold liquid piping and the liquid inlet by the
return liquid piping.
[0008] With this apparatus a number of advantages are achieved. Each individual indoor unit
can be operated as a simple fan unit with a simple heat exchanger. It is not necessary
any more to install a heat pump in each single room. So the indoor units are operated
with water as an environmentally friendly and preferred example for a liquid only,
no refrigerant is used in the rooms any more. The indoor units are less complex, easy
to install and comfortable to use nearly without operational sounds. Due to the reduced
complexity the indoor units are substantially cheaper to manufacture and service,
which adds up to a substantial saving, the more indoor units are installed in a building.
[0009] All the advantages mentioned are especially achieved, by shifting the known ring
pipe to a three-pipe system. By the differentiation of the liquid supply to the indoor
units between warm and cold liquid both pipings are focused upon their individual
function, namely to deliver heating energy by a warm liquid or to collect heat energy
from the respective room by a cold liquid. Whatever a user in a room requires, by
operating an indoor unit to heat or cool the air in a room liquid - either warm or
cold - streams into the indoor unit. In the heat exchanger then either the warmth
is taken from the warm liquid or the heat is added to the liquid in the heat exchanger,
and the liquid leaves the indoor unit with a different temperature level than it has
entered it before, close or even to the local room temperature.
[0010] The return liquid is collected from all single indoor units which are operated in
the building in the return liquid piping. In this way the return liquid piping collects
all heating and cooling requirements in a building by ending up in a definite temperature
of the return liquid at the return liquid inlet. As the individual cooling and heating
requirements in each single room of the building are summarized in the return liquid
temperature, this temperature is very close to the average temperature in the building.
The amount of energy required to cool and/or heat this return liquid back to a required
level is substantially smaller than the energy which would have been required if each
room would have been cooled or heated individually and these individual energy requirements
were added up in a sum.
[0011] Energy savings can be achieved by the advantageous connection of the three pipes
with the condenser and the evaporator on the liquid side and the connection of the
refrigerant piping with the condenser and evaporator. An energy excess or an energy
requirement of the complete system could be leveled out by the operation of the heat
exchanger of the central heat pump unit. If the heat exchanger is cooling down and
condensing the refrigerant flowing through it, excessive energy gets lost, and if
the heat exchanger evaporates and heats the refrigerant, energy is added to the system
over the refrigerant. So the heat exchanger of the central heat pump unit is able
level out a general energy surplus or a general energy requirement from the complete
system.
[0012] An additional advantage is achieved by simplifying the indoor units to simple three
pipes, passive heat exchangers. To operate the indoor units it is sufficient to open
and modulate either a valve in the warm liquid pipe or in the cold liquid pipe, so
that the respective liquid can stream as needed into the heat exchanger. By switching
a fan on which is also a part of the indoor unit the air in the room is blown through
the heat exchanger and thereby cooled or heated. This function of the indoor unit
can be automated and easily remotely controlled by respective controls, if required.
The indoor unit is also able to keep a preselected temperature in the room.
[0013] An indoor unit can be used as a floor, wall and/or ceiling or suspended heating or
cooling unit. Due to the comparably low common favorable temperatures in the three-pipe
system the liquid can also be used as a medium for heating or cooling floors, walls
and/or ceilings of a building. The heating or cooling of floors, walls and/or ceilings
could be reacting slower that the heating or cooling by the indoor units with fans
which are heating or cooling the air in a room, however, a very comfortable and constant
and even heating or cooling function can be achieved thereby, from the same source.
[0014] The energy consumption of the whole system is reduced, as the COP is up to doubled
compared to straight forward heat pump designs. Heat and cold collected in the return
liquid is not wasted in the central heat pump unit, it is primarily exchanged between
the condenser and the evaporator, so that heat generated in a cooling cycle is transferred
to the warm liquid piping, and cold generated in a heating cycle is transferred to
the cold liquid piping. The respective energy needed for cooling and heating is kept
within the system. As the temperatures of the liquid in the warm liquid piping and
the cold liquid piping are differing only by a few degrees from the average temperature
in the building and in the return liquid piping, the heat and cold losses within the
system are very low, whilst the Carnot factor remains high, which additionally increases
the energy efficiency of the system. The indoor units only need electrical power for
operating the fan, there is no compressor to be driven any more. So the energy consumption
of each indoor unit is also reduced.
[0015] According to one embodiment of the invention the central heat pump unit comprises
an electronic control unit which is connected with at least one pressure sensor, which
is measuring a pressure in the refrigerant piping, at least one temperature sensor,
which is measuring a temperature in the refrigerant piping, and a number of valves,
which are arranged within the refrigerant piping, whose switching position influences
the flow of the refrigerant within the refrigerant piping, wherein the positions of
the valves are adjustable by the electronic control unit. By the electronic control
unit, its sensors and valves an automated operation of the complete system is possible.
The operational settings can be programmed in a suitable computer software. The electronic
control system contains the relevant know-how necessary to operate the central heat
pump unit and, in addition to that, if required, also for the complete system including
the indoor units connected with the central heat pump unit. The energy flow between
the condenser, the evaporator, the heat exchanger and the compressor within the central
heat pump unit can be controlled by the electronic control unit. The function of the
electronic control unit can be extended by using currently measured and/or stored
weather information, seasonal information and/or weather forecasts for determining
the right strategies for influencing and storing cold and warm liquids and determining
their temperature threshold values over one day.
[0016] According to one embodiment of the invention a control valve is at least arranged
at each of the pipes from the condenser and the evaporator of the refrigerant piping,
and additional valves can be arranged before and behind the heat exchanger, before
the evaporator, before and behind the condenser, and in a pipe back to the compressor,
all seen in the feeding direction of the refrigerant. These suggested valve positions
are advantageous because they allow an efficient control of the flow of the refrigerant
within the central heat pump unit.
[0017] According to one embodiment of the invention a pressure sensor is at least attached
to the inlet and outlet pipes from the compressor of the refrigerant piping and in
the return liquid piping before the circulation pump, all seen in the feeding direction
of the return liquid. The information about the pressure status at the suggested locations
is helpful to make the right decisions for controlling and steering the function of
the central heat pump unit.
[0018] According to one embodiment of the invention temperature sensors are arranged at
least before the warm liquid outlet and the cold liquid outlet and behind the return
liquid inlet, additional temperature sensors can be arranged in the refrigerant piping
before and behind the compressor, in the heat exchanger and in the evaporator, all
seen in the feeding direction of the liquid or the refrigerant. The knowledge about
the temperatures of the liquid and the refrigerant at the suggested locations helps
to make the right decisions about the settings of the valves within the central heat
pump unit.
[0019] According to one embodiment of the invention the electronic control unit controls
the feeding capacity of the compressor and/or the feeding capacity of at least one
circulation pump being connected with the liquid inlet. By controlling the feeding
capacity of the compressor the cycle of refrigerant within the refrigerant piping
can be activated, capacity controlled, or stopped, whatever is required in a specific
situation. By controlling the feeding capacity of the circulation pump the flow rate
of the liquid through the pipings and the pressure of the liquids can be influenced,
which is relevant for the proper function of the complete system.
[0020] According to one embodiment of the invention the warm liquid outlet is connected
with a warm thermal storage tank, which feeds warm liquid into the warm liquid piping,
and/or the cold liquid outlet is connected with a cold thermal storage tank, which
feeds cold liquid into the cold liquid piping. By integrating thermal storage tanks
into the system it is possible to store some warm and cold thermal energy which can
be reused as a buffer over e.g. a 24 hour cycle of a day.
[0021] According to one embodiment of the invention the warm thermal storage tank and/or
the cold thermal storage tank comprises at least one element with a phase-changing
material. By using a phase-changing material the energy storing capacity of the respective
thermal storage tank can be enhanced, whilst the temperature remains constant.
[0022] According to one embodiment of the invention there is a shortcut link from the warm
thermal storage tank and/or the warm liquid piping to the return liquid piping and
a shortcut link from the cold thermal storage tank and/or the cold liquid piping to
the return liquid piping, both shortcut links are operable by valves, which are either
adjustable due to a differential pressure between the pressure in the warm or cold
thermal storage tank and/or the warm or cold liquid piping on the one side and the
pressure in the return liquid piping on the other side or adjustable by a controlled
drive. Usually the throughput of liquid through the warm liquid pipe system including
the warm thermal storage tank is activated if warm liquid streams into one or more
indoor units. As long as one or more indoor valves are open, there is a current flow
of fresh warm liquid into the warm liquid piping and the warm thermal storage tank.
However, as soon as all valves of the indoor units are closed, the flow in the warm
liquid piping is stopped. If the temperature of the warm liquid in the warm thermal
storage tank and/or the warm liquid piping sinks below a predetermined threshold value,
as no further warm liquid is fed to it from the condenser, the temperature can only
be raised again if there is a shortcut for the warm liquid by which the valves of
the indoor units can be deviated, so that a fresh flow of warm liquid from the condenser
is possible even if all valves of the indoor units are closed. This problem is solved
by the shortcut. This also applies for the cold liquid respectively as explained for
the warm liquid. By using valves as suggested the operation is easy and fail-safe.
[0023] The shortcut link from the cold thermal storage tank and/or the cold liquid piping
to the return liquid piping can also be used to extract energy from the cold thermal
storage tank and/or the cold liquid piping when the heat exchanger needs a temporary
defrosting due to ice build up in humid outside weather conditions. Whilst the defrosting
mode is in operation, the condenser is not in use as the refrigerant pressure in the
frozen heat exchanger is much lower than in the condenser, due to a pressure regulator
valve at the outlet of the condenser. As it may be likely that no indoor unit requires
cooling either, the flow in the cool liquid piping may become absent, which would
hinder the evaporator to work properly. Then the bypass valve and the cold thermal
storage tank and/or the cold liquid piping are activated accordingly in this mode.
[0024] According to one embodiment of the invention the connection of the indoor unit with
the warm liquid piping is regulated by a first valve and the connection of the indoor
unit with the cold liquid piping is regulated by a second valve, both valves being
adjustable or modulated due to the heating or cooling operation of the indoor unit,
and the connection of the indoor unit with the return liquid piping can be regulated
or modulated by an adjustable maximum flow limiter valve. By the first and second
valves the temperature of the liquid flowing through the indoor unit can be adjusted
precisely by regulating the portions of cold and warm liquid streaming into the indoor
unit with the valves. If a full heating is required, then only the valve of the warm
liquid piping is open, and if a full cooling is required, then only the valve of the
cold liquid pipe system is open. If no temperature adjustment is needed in the respective
room both valves are closed. If a minor temperature adaption in the room is required,
then any relative appropriate mixture of throughput of the warm and cold liquid can
be selected by the respective operational settings of the respective valves. By the
option to regulate the throughput of liquid through the indoor unit generally the
function of the indoor unit can better be controlled, and flow related on site commissioning
activities are eliminated.
[0025] The indoor unit can comprise an electronic indoor unit control unit which is connected
with at least one temperature sensor, which is measuring a temperature of the liquid
flowing into the indoor unit, at least one temperature sensor, which is measuring
a temperature in the room in which the indoor unit is positioned, and adjustment drives
of the first and second valves and optionally the adjustable maximum flow limiter
valve, wherein the position of each of the valves is adjustable by the electronic
indoor unit control unit. By the electronic indoor unit control unit the function
of the indoor unit can be automated. Also the settings can be selected remotely. A
preselection of a certain temperature in the room is possible by a user, and the electronic
indoor unit control unit then operates the valves according to an appropriate software
as it is necessary to achieve and keep the preselected temperature in the respective
room.
[0026] According to one embodiment of the invention the electronic indoor unit control unit
is connected with the electronic control unit of the central heat pump unit. By the
connection of and the communication between the respective control units the operation
of both control units can be optimized.
[0027] According to one embodiment of the invention the warm liquid piping and/or cold liquid
piping is connected to an external heat exchanger for injecting external heat or cold
to the liquid. The external heat exchanger could be connected to a pond, a lake or
a river, a sprinkler tank, a swimming pool or a specific water tank or any source
of heat by boiler, collector, waste heat or other sources of thermal energy, to use
the energy or cold from the water available there, or it could be adapted to use geothermal
energy for storing and extracting energy from the ground.
[0028] According to one embodiment of the invention the central heat pump unit is designed
as an outdoor unit arranged outside of the building. By this design no space inside
of the building gets lost which is usable for other purposes, the heat exchanger can
directly blow the heated or cooled air into the surrounding, the operational sound
of the central heat pump unit is kept outside of the building and servicing of the
unit is easier due to a better accessibility. Even an exchange of the complete unit
is possible very quickly, if that should be required. By designing the central heat
pump unit as an outdoor unit there is no refrigerant in the building.
[0029] According to one embodiment of the invention the warm, cold and return liquid is
water. Water is environmentally friendly and even if a pipe should leak it doesn't
cause a danger for persons in the building. It has a high energy loading capacity
and it is ideal for being used as a carrier for energy.
[0030] According to one embodiment of the invention the condenser, the evaporator and/or
the heat pump in the central heat pump unit are connected to the refrigerant piping
with 2-way valves, and especially the heat exchanger with two 2-way valves. The inventive
central heat exchanger unit comprises three heat exchangers: the evaporator, the condenser
and the air to refrigerant or refrigerant to air heat exchanger. The heat exchanger
- air to refrigerant or refrigerant to air - is not connected to a 4-way valve though
being operable in two modes. With the suggested connections of the respective units
it is possible to operate the central heat pump unit with 2-way valves, and especially
the heat exchanger with only two 2-way valves. This is a big advantage, because the
condenser, the evaporator and/or the heat exchanger can be optimized to just one flowing
direction of each, the liquid or the air and the refrigerant, through the heat exchanger.
The heat exchangers achieve the best function and heat exchange rate, if the flows
of the liquid or air on the one side and the refrigerant on the other side in the
heat exchanger are arranged in a counter flow.
[0031] The problem is solved by a method, which is characterized by the following elements:
- the liquid leaving the central heat pump unit is distributed to the at least one indoor
unit through a warm liquid piping and a cold liquid piping, and the liquid returning
to the central heat pump unit from the at least one indoor unit is distributed by
a return liquid piping,
- the electronic control unit operates control valves of the refrigerant piping being
controlled by the electronic control unit and arranged in the central heat pump unit
as follows, if the temperature of the return liquid is
either above a predetermined threshold value and the return liquid is fed through
the evaporator and fed from the evaporator to the cold liquid piping: the refrigerant
is being fed through the evaporator and thereafter to the compressor, the heat exchanger
and/or the condenser and/or the liquid receiver,
or below a predetermined threshold value and the return liquid is fed though the condenser
and fed from the condenser to the warm liquid piping: the refrigerant is being fed
through the condenser and thereafter to the evaporator and/or the heat exchanger and
a liquid receiver.
[0032] The advantages of the three-pipe system is already explained above, all advantages
described also apply for the claimed method.
[0033] By the claimed operation of the electronic control unit in connection with the three-pipe
system for the liquid it is possible to run the central heat pump unit with very low
/ minimal energy losses and a very high to double energetic efficiency. By all feeding
options for the refrigerant after it was fed through the condenser or the evaporator
the electronic control unit can choose the most energy efficient option or choose
a solution where the refrigerant is fed to two or all options if it seems to be appropriate.
[0034] According to one embodiment of the method invention the temperature of the return
liquid is kept in a range of plus/minus 8 K around 22° C by the electronic control
unit by operating the compressor and/or a circulation pump in addition to the operation
of the control valves. If the temperature of the return liquid is kept in the indicated
temperature range the whole system can be operated very efficiently. If the temperature
of the return liquid gets too high or too low, the electronic control unit can adjust
the circulation pump and/or the compressor, so that due to the flow of the liquid
through the system the liquid could either be cooled down or heated up, as it may
ever be required. However, the main control of the central heat pump unit must not
necessarily completely or predominantly be influenced by the average return pipe temperature,
also the actual cold and warm liquid temperatures can be integrated into the control
strategy, and weather, time, forecasts or historically stored data and set points
could be considered by the controls as well.
[0035] According to one embodiment of the method invention the electronic control unit regulates
the temperature of the warm liquid at a warm liquid outlet to a value of 30° C plus/minus
8 K and the temperature of the cold liquid at a cold liquid outlet to a value of 15°
C plus/minus 8 K by the operation of the valves and the compressor and/or the circulation
pump. These temperature ranges have proven to be very energy efficient, and at these
temperatures it is possible to provide reasonable reaction times of the indoor units
to adapt and regulate the temperature in a room towards a selected temperature. Thermal
losses are low to neglectible due to minimum differences with the building temperature.
[0036] According to one embodiment of the method invention the electronic control unit activates
the circulation pump and/or the compressor, if the temperature in a warm storage thermal
tank and/or the warm liquid piping is dropping below a predetermined threshold value
and/or the temperature in a cold storage thermal tank and/or the cold liquid piping
is rising over a predetermined threshold value. By the activation of the compressor
and/or the circulation pump the temperatures in these elements can be kept on the
desired levels.
[0037] According to one embodiment of the method invention the cold thermal energy contained
in the cold thermal storage tank or the warm thermal energy contained in the warm
thermal storage tank is added to the liquid flow under peak load conditions of the
central heat pump unit. Due to the thermal storage the system is able to store cold
and/or warm energy at times when the central heat pump unit is not cooling or heating
under peak load conditions. If peak load conditions for cooling or heating appear,
the stored thermal capacities can then be activated by allowing cold or warm liquid
from the cold or warm thermal storage tank to be added to the liquid flow through
the system, so that the technical peak load of the central heat pump unit under the
prevailing conditions is boosted by the added thermal energy from the respective thermal
storage tank. The peak load conditions in the sense of this claim also apply when
the theoretical current peak load operation of the central heat pump unit is shifted
to other times of the day and the theoretical peak load is nevertheless reached by
replacing thermal capacities missing to the theoretical peak load of the central heat
pump unit under its current operation mode by the activation of thermal capacities
from the thermal storage tanks. This could be useful to ease the grid load upon an
electric network at a specific time, or cost efficiency of the operation can be enhanced.
This option improves the sustainability of the system even further.
[0038] It is expressively noted that each of the embodiments mentioned above can be combined
with the elements of the independent claims and the other dependent claims, as far
as it makes a technical sense.
[0039] Further details of the invention are described in the following example of the invention,
which is also described in more detail in the attached drawings. It is shown in
Fig. 1: a principle drawing of the central heat pump unit,
Fig. 2: a principle drawing of an indoor unit, and
Fig. 3: a principle drawing of a complete system.
[0040] In Fig. 1 a principle drawing of a central heat pump unit 2 is shown. The central
heat pump unit 2 comprises a condenser 4, an evaporator 6, a compressor 8 and a heat
exchanger 10. Albeit of the example shown in Fig. 1 there can be more than just one
compressor 8. The liquid which is flowing through the central heat pump unit 2 is
guided into the building, in which the temperature shall be influenced, through a
warm liquid outlet 12 and a cold liquid outlet 14. The liquid which has been used
in indoor units in the building for heating and/or cooling purposes is returning to
the central heat pump unit through a liquid inlet 16.
[0041] The condenser 4, the evaporator 6, the compressor 8 and the heat exchanger 10 are
connected by a refrigerant piping 18, through which a refrigerant is fed. The moving
direction of the refrigerant is indicated by little arrows along the respective pipes.
There also pipe 22 which can be used for shifting the flow of the refrigerant in a
desired way. The refrigerant is pumped up to a high pressure gaseous phase in the
compressor 8. From there it is guided to the condenser 4. In the condenser 4 the refrigerant
condenses, thereby the refrigerant loses energy, which is transferred to the warm
liquid which is flowing through the condenser 4 and which is warmed up by the energy
added to it. The liquefied refrigerant is then distributed by the refrigerant piping
18 towards the evaporator 6. Before it reaches the evaporator 6 the liquefied refrigerant
is fed through the heat exchanger 10, from where it is subcooled, after it has left
the heat exchanger 10, and it is fed into a liquid receiver 56 for the liquid refrigerant.
[0042] There are two additional temperature/pressure control pipes 24 connecting two sensor
bulbs both at the outlet of the heat exchanger 10 and the outlet of the evaporator
6, to control the evaporation process of the evaporator 6 by an expansion device at
the inlet of the evaporator 6, and similar to control the evaporation process of the
heat exchanger 10 in case that the heat exchanger 10 is activated as evaporator by
the valves 20. Their necessity is given by the fact that both evaporation processes
are not operated at similar conditions, temperatures and suction pressures.
[0043] In the evaporator 6 the refrigerant gets evaporated and warmed up by the return liquid,
which is fed into the central heat pump unit 2 by the circulation pump 26. The return
pipe for the return liquid is split up in the central heat pump unit 2 so that the
return liquid can either flow to the condenser 4 and/or to the evaporator 6. By that
amount of energy by which the refrigerant is evaporated and warmed up in the evaporator
6 the cold liquid flowing through the evaporator 6 at the same time is cooled down
respectively.
[0044] In Fig. 1 two circulation pumps 26 are shown just as an example. From the evaporator
6 the refrigerant is guided back through an accumulator 58 to the compressor 8 again.
From there the feeding cycle can start again.
[0045] The warm liquid which has been warmed up in the condenser 4 is guided by a respective
pipe towards the warm liquid outlet 12. The pipe feeds the warm liquid into a warm
thermal storage tank 28, which can be integrated into the central heat pump unit 2
optionally. From the warm thermal storage tank 28 it reaches the warm liquid outlet
12. The cold liquid which has been cooled down in the evaporator 6 is guided by a
respective pipe towards the cold liquid outlet 14. The pipe feeds the cold liquid
into a cold thermal storage tank 30, which can also be integrated into the central
heat pump unit 2 optionally. From there it reaches the cold liquid outlet 14.
[0046] If there is no water flowing through the warm liquid outlet 12, but the content in
the warm thermal storage tank 28 and/or the warm liquid piping 38 needs to be increased
and exchanged, then the warm liquid can flow through the shortcut link 32 to the return
liquid piping 42. If there is no water flowing through the cold liquid outlet 14,
but the content in the cold thermal storage tank 30 and/or the cold liquid piping
40 needs to be decreased and exchanged, then the cold liquid can flow through the
shortcut link 34 to the return liquid piping 42. The shortcut links can be activated
by valves 20. The shortcut links 32, 34 can be arranged in the central heat pump unit
2, but also anywhere in the building, so that the temperature levels of the warm and
cold liquids within the building can better be maintained and the reaction times of
the indoor units 36 are faster, if preselected temperatures in a room are altered.
[0047] The central heat pump unit comprises an electronic control unit (not shown) which
is connected with pressure sensors PT shown in Fig. 1. The pressure sensors PT are
measuring a pressure in the refrigerant piping 18 at the respective position. There
are also some temperature sensors TT attached to the refrigerant piping 18, which
are measuring the temperature of the refrigerant at the specific position in the refrigerant
piping 18. The flow of the refrigerant within the refrigerant piping 18 is controlled
by a number of valves 20. The switching position of the valves 20 influences the flow
of the refrigerant within the refrigerant piping 18. The switching positions of the
valves 20 are adjustable by the electronic control unit by controlling adjustment
drives of the valves 20, so that the refrigerant piping can be opened or closed at
its respective positions, or the throughput of refrigerant can be restricted to a
desired extent, whatever is necessary for the proper function of the central heat
pump unit 2. By the readings of the pressure sensors PT and the temperature sensors
TT the electronic control unit is able to recognize by an appropriate software, how
the valves 20 for regulating the flow of the refrigerant need to be switched, so that
the heating and cooling requirements of the users in the building can be satisfied
and the temperatures of the warm and cold liquids flowing through the warm and cold
liquid outlets 12, 14 are kept on appropriate levels. The flow of the refrigerant
in the refrigerant piping is also influenced by the operation mode of the compressor,
which can be modulated or switched on or off by the electronic control unit. If an
excess of energy in the central heat pump unit 2 needs to be rejected, then the refrigerant
can be guided through the heat exchanger 10 by respective switching positions of the
valves 20. This can also be made for an injection of energy, if required, by the heat
exchanger 10 in a reverse operation.
[0048] By controlling the temperatures of the liquids flowing through the warm liquid outlet
12, the cold liquid out 14 and the liquid inlet 16 the electronic control unit is
aware of the temperature levels of the liquids in the respective pipings. By a comparison
of the temperature changes of the respective liquids over a certain period the electronic
control unit is able to determine, whether there is a general requirement for heating
and/or cooling the building. A rise of the temperature of the return liquid indicates
a cooling requirement, and a decline of the temperature of the return liquid indicates
a heating requirement. The temperature data can be compared to air temperatures outside
of the building, the time of the day, the season, weather forecasts and the like.
If a higher cooling demand can be expected, the temperature and energy level in the
cold thermal storage tank and/or in the cold liquid piping can be lowered in relation
to the average value, and if a heating demand is expected then the energy level and
the temperature in the warm thermal storage tank and/or in the warm liquid piping
can be raised. Due to the energetic connection of the condenser 4 and the evaporator
6 by the refrigerant piping the energy consumed or collected by the respective process
of heating or cooling the liquid in the pipings or thermal storage tanks can be transferred
to each other, so that a reduction of the energy level and temperature in the cold
thermal storage tank and/or in the cold liquid piping leads to an increase of the
energy level and temperature in the warm thermal storage tank and/or in the warm liquid
piping and vice versa, without needing additional energy from other resources. So
a simultaneous thermal heating or cooling or a preloading for these functions builds
up energy resources for the inverse process. If at a different time of the day the
general heating requirement is shifted towards a cooling requirement, then the preloaded
respective energies can again be exchanged between the cold and warm liquid systems,
so that again no other energy resources are required to cover that air conditioning
demand in the building as long as the saved energy reserves can be used. If beyond
this exchange of energy between the warm and cold liquid systems by the central heat
pump unit additional energy is required or excessive energy needs to be disposed of,
this can be handled to some extent by the heat exchanger 10, so that regular energy
resources like electricity, gas, oil or like are only need to a very limited extent
or are avoided.
[0049] In Fig. 2 a single indoor unit 36 is shown. The indoor unit 36 shown is connected
with the warm liquid outlet 12 of the central heat pump unit 2 by the warm liquid
piping 38 and with the cold liquid outlet 14 of the central heat pump unit 2 by the
cold liquid piping 40. The indoor unit 36 is also connected with the liquid inlet
16 by the return liquid piping 42. The indoor unit 36 comprises a heat exchanger 10.
Depending from the switching position of the valves 20 at the warm and cold liquid
pipings 38, 40 liquid with a certain temperature is flowing into the feed pipe 44
to the heat exchanger 10. The fan unit 46 is sucking air from the room through the
heat exchanger 10. If the liquid flowing through the feed pipe 44 is warmer than the
air flowing through the heat exchanger 10 the air is heated, and if the liquid is
colder, then the air is cooled. The throughput of liquid through the indoor unit can
additionally be controlled by an adjustable flow limiter valve 54, which is positioned
in the return liquid piping 42.
[0050] The indoor unit 36 may comprise an electronic indoor unit control unit (not shown)
which is connected with a temperature sensor TT, which is measuring a temperature
of the liquid flowing into the indoor unit 36 through the feed pipe 44, and a temperature
sensor TT, which is measuring a temperature in the room in which the indoor unit 36
is positioned. The electronic indoor unit control unit can also be connected with
adjustment drives of the first and second valves 20 at the warm and cold liquid pipings
and optionally with a drive of the adjustable flow limiter valve 20. So the operating
position of each of the valves 20 is controlled and adjustable by the electronic indoor
unit control unit. If a user preselects a desired temperature in the room, and the
preselected temperature differs from the temperature measured by the temperature sensor
TT in the room, then the electronic indoor unit control unit recognizes whether the
room needs to heated or cooled. The electronic indoor unit control unit will then
open either the valve 20 to the warm liquid piping 38 or to the cold liquid piping
40, so that the respective liquid flows into the heat exchanger 10. Upon activation
of the fan unit 46 the air in the room is then cooled or heated. The respective valve
will be kept open or is modulated as long as the electronic indoor unit control unit
recognizes a heating or cooling requirement. The electronic indoor unit control unit
could also completely or partially open each of both valves to the warm and cold liquid
pipings 38, 40 at the same time, so that both liquids get mixed in the feed pipe 44
and a temperature of the liquid is achieved which is between the temperatures of the
warm and cold liquid. The electronic indoor unit control unit can be connected by
option with the electronic control unit of the central heat pump unit 2. Then the
electronic control unit could get an information about cooling or heating requirements
in that room, before the temperature of the return liquid changes. If the electronic
control unit knows the temperature difference between the preselected temperature
and the current temperature, the electronic control unit can also make an estimation
about the required amount of heating or cooling and for the time in which the respective
function is required. If the electronic control unit gets this information from most
or all indoor units 36 installed in the building the electronic control device is
able to optimize the operation of the central heat pump unit 2, and to maximize a
thermal favorable operation, storage and sustainable operation, to minimize any external
energy consumption.
[0051] In Fig. 3 a complete system for a building is shown. The warm liquid flows through
the warm liquid piping 38 and the warm liquid outlet 12 into the building. The cold
liquid flows through the cold liquid piping 40 and the cold liquid outlet 14 into
the building. Optionally there could be an additional warm thermal storage tank 28
and/or a cold thermal storage tank 40 connected to the warm and cold liquid pipings
38, 40. As a further option an external heat exchanger 48 connected to the warm liquid
piping 38 and an external heat exchanger 50 connected to the cold liquid piping is
shown. Such external heat exchangers 48, 50 could be connected to the ground, it could
be earth tanks, water reservoirs, (waste) heat sources or the like. The warm and cold
liquids can flow into the four indoor units 36, 36a. The indoor unit 36a is shown
as an embedded underfloor heating and/or cooling system, which exchanges energy through
the side walls of the pipe and not through a special heat exchanger 10 and a fan unit
46. The liquid which flows into the indoor units 36 flows into the return liquid piping
42, which mounts in the liquid inlet 16 of the central heat pump unit 2. The return
liquid piping 42 is connected to an optional passive thermal storage means, which
could for example be the ceilings, walls or the like of the building using the internal
thermal mass of the building.
[0052] The invention has been described by virtue of the example mentioned above. The invention
is not limited to this example, an expert could make amendments of the example which
deem to be appropriate to him, without leaving the subject of the invention.
1. Apparatus for influencing the temperature in a building, comprising:
- a central heat pump unit (2) with a warm liquid outlet (12) to a warm liquid piping
(38), a cold liquid outlet (14) to a cold liquid piping (40) and a liquid inlet (16)
connected with a return liquid piping (42),
- a condenser (4) as a part of the central heat pump unit (2) being connected with
the warm liquid outlet (12) and the liquid inlet (16),
- an evaporator (6) as a part of the central heat pump unit (2) being connected with
the cold liquid outlet (14) and the liquid inlet (16),
- a compressor (8) as a part of the central heat pump unit (2) to pressurize a refrigerant,
- a heat exchanger (10) as a part of the central heat pump unit (2) to evaporate and
heat or to condensate and cool the refrigerant,
- a refrigerant piping (18) as a part of the central heat pump unit (2) being connected
with the condenser (4), the evaporator (6), the compressor (8) and the heat exchanger
(10), which distributes the refrigerant in the central heat pump unit (2), and
- at least one indoor unit (36) being connected with the warm liquid outlet (12) by
the warm liquid piping (38), the cold liquid outlet (14) by the cold liquid piping
(40) and the liquid inlet (16) by the return liquid piping (42).
2. Apparatus according to claim 1, characterized in, that the central heat pump unit (2) comprises an electronic control unit which is connected
with at least one pressure sensor (PT), which is measuring a pressure in the refrigerant
piping (18), at least one temperature sensor (TT), which is measuring a temperature
in the refrigerant piping (18), and a number of valves (20), which are arranged within
the refrigerant piping (18), whose switching position influences the flow of the refrigerant
within the refrigerant piping (18), wherein the positions of the valves (20) are adjustable
by the electronic control unit.
3. Apparatus according to claim 2, characterized in, that a valve (20) is at least arranged at each of the pipes from the condenser (4) and
the evaporator (6) of the refrigerant piping (18), and additional valves (20) can
be arranged before and behind the heat exchanger (10), before and behind the evaporator
(6) before and behind the condenser (4), and in a pipe (22) back to the compressor
(8), all seen in the feeding direction of the refrigerant.
4. Apparatus according to claim 2 or 3, characterized in, that a pressure sensor (PT) is at least attached to the inlet and outlet pipes from the
compressor (8) of the refrigerant piping (18) and in the return liquid piping (42)
before the circulation pump (26), all seen in the feeding direction of the return
liquid.
5. Apparatus according to any of preceding claims 2 to 4, characterized in, that temperature sensors (TT) are arranged at least before the warm liquid outlet (12)
and the cold liquid outlet (14) and behind the return liquid inlet (16), additional
temperature sensors (TT) can be arranged in the refrigerant piping (18) before and
behind the compressor (8), in the heat exchanger (10) and in the evaporator (6), all
seen in the feeding direction of the liquid or the refrigerant.
6. Apparatus according to any of preceding claims 2 to 5, characterized in, that the electronic control unit controls the feeding capacity of the compressor (8) and/or
the feeding capacity of at least one circulation pump (26) being connected with the
liquid inlet (16).
7. Apparatus according to one of the preceding claims, characterized in, that the warm liquid outlet (12) is connected with a warm thermal storage tank (28), which
feeds warm liquid into the warm liquid piping (38), and/or the cold liquid outlet
(14) is connected with a cold thermal storage tank (30), which feeds cold liquid into
the cold liquid piping (40), and the warm thermal storage tank (28) and/or the cold
thermal storage tank (30) can comprise at least one element with a phase-changing
material.
8. Apparatus according to claim 7, characterized in, that that there is a shortcut link (32) from the warm thermal storage tank (28) and/or
the warm liquid piping (38) to the return liquid piping (42) and a shortcut link (34)
from the cold thermal storage tank (30) and/or the cold liquid piping (40) to the
return liquid piping (42), both shortcut links (32, 34) are operable by valves (20),
which are either adjustable due to a differential pressure between the pressure in
the warm or cold thermal storage tank (28, 30) and/or the warm or cold liquid piping
(40) on the one side and the pressure in the return liquid piping (42) on the other
side or adjustable by a controlled drive.
9. Apparatus according to one of the preceding claims, characterized in, that the connection of the indoor unit (36) with the warm liquid piping (38) is regulated
by a first valve (20) and the connection of the indoor unit (36) with the cold liquid
piping (40) is regulated by a second valve (20), both valves (20) being adjustable
due to the heating or cooling operation of the indoor unit (36), and the connection
of the indoor unit (36) with the return liquid piping (42) can be regulated by an
adjustable maximum flow limiter valve (20).
10. Apparatus according to claim 9, characterized in, that the indoor unit (36) comprises an electronic indoor unit control unit which is connected
with at least one temperature sensor (TT), which is measuring a temperature of the
liquid flowing into the indoor unit (36), at least one temperature sensor (TT), which
is measuring a temperature in the room in which the indoor unit (36) is positioned,
and adjustment drives of the first and second valves (20) and optionally the adjustable
maximum flow limiter valve (20), wherein the position of each of the valves (20) is
adjustable by the electronic indoor unit control unit.
11. Apparatus according to claim 10, characterized in, that the electronic indoor unit control unit is connected with the electronic control
unit of the central heat pump unit (2).
12. Apparatus according to one of the preceding claims, characterized in, that the warm liquid piping (38) and/or cold liquid piping (40) is connected to an external
heat exchanger for injecting external heat or cold to the liquid.
13. Apparatus according to one of the preceding claims, characterized in, that the central heat pump unit (2) is designed as an outdoor unit arranged outside of
the building.
14. Apparatus according to one of the preceding claims, characterized in, that the warm, cold and return liquid is water.
15. Apparatus according to one of the preceding claims, characterized in, that the condenser (4), the evaporator (6) and/or the heat exchanger (10) in the central
heat pump unit (2) are connected to the refrigerant piping (18) with 2-way valves
(20), and especially the third heat exchanger (10) with two 2-way valves (20).
16. Method for operating an apparatus for influencing the temperature in a building comprising
a central heat pump unit (2) with a condenser (4), an evaporator (6), a compressor
(8), a heat exchanger (10) and an electronic control unit, which operates the flow
of a refrigerant within a refrigerant piping (18) for the refrigerant inside of the
central heat pump unit (2), the central heat pump unit (2) being connected to a piping
for distributing liquid through the building from the central heat pump unit (2) to
at least one indoor unit (36) and back,
characterized in, that:
- the liquid leaving the central heat pump unit (2) is distributed to the at least
one indoor unit (36) through a warm liquid piping (38) and a cold liquid piping (40),
and the liquid returning to the central heat pump unit (2) from the at least one indoor
unit (36) is distributed by a return liquid piping (42),
- the electronic control unit operates control valves (20) of the temperature sensor
(TT) being controlled by the electronic control unit and arranged in the central heat
pump unit (2) as follows, if the temperature of the return liquid is
either above a predetermined threshold value and the return liquid is fed through
the evaporator (6) and fed from the evaporator (6) to the cold liquid piping (40):
the refrigerant is being fed through the evaporator (6) and thereafter to the compressor
(8), the heat exchanger (10) and/or the condenser (4) and/or the liquid receiver (56),
or below a predetermined threshold value and the return liquid is fed though the condenser
(4) and fed from the condenser (4) to the warm liquid piping (38): the refrigerant
is being fed through the condenser (4) and thereafter to the evaporator (6) and/or
the heat exchanger (10) and a liquid receiver (56).
17. Method according to claim 16, characterized in, that the temperature of the return liquid is kept in a range of plus/minus 8 K around
22° C by the electronic control unit by operating the compressor (8) and/or a circulation
pump (26) in addition to the operation of the control valves (20).
18. Method according to any of the preceding claims 16 or 17, characterized in, that the electronic control unit regulates the temperature of the warm liquid at a warm
liquid outlet (12) to a value of 30° C plus/minus 8 K and the temperature of the cold
liquid at a cold liquid outlet (14) to a value of 15° C plus/minus 8 K by the operation
of the valves (20) and the compressor (8) and/or the circulation pump (26).
19. Method according to any of the preceding claims 16 to 18, characterized in, that the electronic control unit activates the circulation pump (26) and/or the compressor
(8), if the temperature in a warm storage thermal tank (28) is dropping below a predetermined
threshold value and/or the temperature in a cold storage thermal tank (30) is rising
over a predetermined threshold value.
20. Method according to any of the preceding claims 16 to 19, characterized in, that the cold thermal energy contained in the cold thermal storage tank (30) or the warm
thermal energy contained in the warm thermal storage tank (28) is added to the liquid
flow under peak load conditions of the central heat pump unit (2).