handbuch

Index

1

Index

PREAMBLE ___________________________________________________________________________________________________________3

1 BODY TEMPERATURE, COMFORT, HOURS AT FULL UTILISATION _____________________________________4 1.1 Comfort ___________________________________________________________________________________________________________________ 4 1.2 Hours at full utilisation for providing cooling ____________________________________________________________________ 5 2 BASES_______________________________________________________________________________________________________7 2.1 Air-conditioning, cooling and tempering _________________________________________________________________________ 7 2.2 Passive and active cooling____________________________________________________________________________________________ 7 2.2.1 Passive cooling__________________________________________________________________________________________________________ 8 2.2.2 Active cooling ___________________________________________________________________________________________________________ 8 2.3 Heat cooling sources__________________________________________________________________________________________________10 2.3.1 Ground probes _________________________________________________________________________________________________________10 2.3.2 Ground collectors______________________________________________________________________________________________________11 2.3.3 Groundwater ___________________________________________________________________________________________________________12 2.3.4 Air ________________________________________________________________________________________________________________________12 2.4 Distribution systems __________________________________________________________________________________________________12 2.4.1 Area heating (underfloor) ___________________________________________________________________________________________13 2.4.2 Area heating (ceiling) ________________________________________________________________________________________________13 2.4.3 Fan convectors and ceiling cassettes ______________________________________________________________________________14 3 H-X DIAGRAM AND DEW POINT TEMPERATURE ______________________________________________________14

4 COOLING WITH BRINE|WATER HEAT PUMPS __________________________________________________________17 4.1 Sizing ____________________________________________________________________________________________________________________17 4.2 Operating modes WPF________________________________________________________________________________________________17 4.2.1 Heating mode WPF____________________________________________________________________________________________________17 4.2.2 Passive cooling operation with WPF_______________________________________________________________________________18 4.3 Operating modes WPC cool__________________________________________________________________________________________18 4.3.1 Heating mode WPC cool______________________________________________________________________________________________18 4.3.2 Passive cooling operation with WPC cool ________________________________________________________________________18 4.4 Active cooling operation WPF and WPC___________________________________________________________________________18 4.4.1 Minimum flow rate for active cooling _____________________________________________________________________________19 4.5 Valve positions _________________________________________________________________________________________________________19 4.5.1 Passive cooling_________________________________________________________________________________________________________19 4.5.2 Active cooling __________________________________________________________________________________________________________19 4.5.3 Cooling and DHW demand___________________________________________________________________________________________20 4.6 Hydraulics WPF ________________________________________________________________________________________________________21 4.7 Hydraulics WPF with WPAC 1 _______________________________________________________________________________________22 4.8 Hydraulics WPC cool __________________________________________________________________________________________________23 4.9 Hydraulics WPF with WPAC 2 _______________________________________________________________________________________24 5 COOLNG WITH WATER|WATER HEAT PUMPS __________________________________________________________25 5.1 Sizing ____________________________________________________________________________________________________________________25 5.2 Operating modes ______________________________________________________________________________________________________25 5.2.1 Heating operation _____________________________________________________________________________________________________25 5.2.2 Passive cooling operation ___________________________________________________________________________________________26 5.2.3 Active cooling operation _____________________________________________________________________________________________26 6 COOLING WITH AIR|WATER HEAT PUMPS______________________________________________________________27

7 SETTING PARAMETERS OF AND CONTROL WITH THE WPMI _________________________________________28 7.1 Standard settings______________________________________________________________________________________________________29 7.2 Set room temperature ________________________________________________________________________________________________29 7.3 Flow temperature _____________________________________________________________________________________________________29 7.4 Flow temperature hysteresis________________________________________________________________________________________29 7.5 Dynamic (active cooling only)_______________________________________________________________________________________30 7.6 Control characteristics of the passive cooling ___________________________________________________________________30

Index

2

7.6.1 Source pump ___________________________________________________________________________________________________________30 7.7 Control characteristics of the active cooling _____________________________________________________________________31 7.7.1 Compressor _____________________________________________________________________________________________________________32 8 BRINE RESISTANCE_______________________________________________________________________________________33

9 WIRING CHANGEOVER COOLING MODE ________________________________________________________________34 9.1 Wiring diagram ________________________________________________________________________________________________________34 9.2 Distribution strip/zone valve ________________________________________________________________________________________37 10 COMPARISON COOLING WITH DIFFERENT HEAT PUMPS _____________________________________________40

11 ALTERNATIVE SYSTEMS AND COST CONSIDERATIONS _______________________________________________41 11.1 VRF systems, air-conditioning systems with direct evaporation_____________________________________________41 11.2 Free cooling ____________________________________________________________________________________________________________41 11.3 Air duct __________________________________________________________________________________________________________________41 11.4 Water wall ______________________________________________________________________________________________________________41 11.5 Cost consideration_____________________________________________________________________________________________________42 11.5.1 Recommendations ____________________________________________________________________________________________________43 12 COOLING LOAD CALCULATION FORM ___________________________________________________________________44

13 CHECK LIST ________________________________________________________________________________________________45

14 BIBLIOGRAPHY____________________________________________________________________________________________46

15 KEYWORD INDEX _________________________________________________________________________________________47

PREAMBLE

3

PREAMBLE

This manual is designed to provide an overview on the subject of cooling buildings with heat

pumps. It is designed for the trade and design engineers and represents a supplement to the

technical folder "Heat pumps".

In part I, the essential basics are explained, together with the influencing magnitudes of

ambient climate and comfort, as well as listing the differences between air-conditioning,

cooling and tempering. Furthermore, there will be a brief introduction relating to the h-x

diagram and the dew point.

The essential characteristics of passive and active cooling are explained, and diverse possible

heat sources and distribution systems are introduced.

The main part of this manual describes cooling with the various Stiebel Eltron heat pumps and

their corresponding WPMi control unit.

This overview provides information regarding possible application areas, sizing and

design/engineering. Important control variables, setting parameters and the respective

hydraulic diagrams are also illustrated.

The manual closes with an introduction of alternative systems for ambient cooling and costing

samples. The cost consideration includes a comparison of the different cooling systems by way

of an example: Active and passive cooling, room air-conditioning units and VRF air-

conditioning systems.

BODY TEMPERATURE, COMFORT, HOURS AT FULL UTILISATION

4

1 BODY TEMPERATURE, COMFORT, HOURS AT FULL UTILISATION

It is important for human beings to maintain a constant body temperature. For this to happen,

there must be balance between internal heat production and heat transfer to the ambience.

Internal heat production is primarily the result of the so-called activity level. Seated activities,

such as writing and reading, for example, represent activity level I.

On average, humans generate heat at 100 W. This exerts an influence on the heat added to the

ambient climate in much the same way as an installed device or a piece of lighting equipment.

Table 1 Heat production subject to activity in accordance with DIN 1946-2

Activity

level

Activity Heat production

per person [W]

Specific heat production

[W/m²]

- Basic metabolic rate 79 44

I Seated activity, such as

writing or reading

100 56

II Light work whilst standing

up, such as laboratory work,

typing

150 83

III Moderately heavy physical

activity

200 111

IV Heavy physical activity >250 >140

The heat transfer to ambience is subject to the climatic conditions of the surroundings and the

level of clothing. In the latter case, transfer is effected through radiation, convection, conduction

and water vapour diffusion. /2/

To maintain the heat balance, humans possess an effective temperature control system. For

example, an increase in blood circulation and dissipation of sweat can substantially increase

heat transfer to the ambience. /2/

Humans are able to store chemical energy, for example in the form of fat deposits. However,

humans have hardly any thermal storage capacity. Heat is produced constantly and transferred

to the ambience.

1.1 Comfort

The conditions at which humans perceive their thermal ambience as pleasant, in other words

when there is an equilibrium between the internal heat production and heat transfer, is

described as comfortable. Thermal comfort is a subjective perception variable that depends on

the ambience and the individual person.


5

Human comfort decreases with ambient temperatures that are too low or too high. Excessive

temperatures can also severely reduce human output/capacity. Consequently, living and

working environments should provide a comfortable climate.

The following terms are summarised under the comfort influencing variables:

- Activity level

- Clothing

- Air temperature

- Temperature of the surface areas enclosing the ambient space

- Relative humidity

- Air velocity

- Air purity

These different variables have lead to the assessment and evaluation of the ambient climate

being generally based on the comfort field developed by Leusden and Freymark, see diagram 1.

/2/ /4/

The following comfort diagram by Leusden and

Freymark illustrates the relationship between two

factors: Relative humidity and ambient

temperature.

For example, one person may not discern any

substantial loss in comfort at an ambient

temperature of 22 °C and a relative humidity

between 30 % and 70 %. He/she would perceive

both air conditions as equally pleasant.

Figure 1 Comfort field according to Leusden and Freymark

1.2 Hours at full utilisation for providing cooling

Buildings that require a higher cooling demand include offices, buildings for wholesalers and

retailers, hospitals, theatres, cinemas, as well as hotels and apartments. Generally, with

cooling, the internal temperature should only be reduced by approx. 3 to 6 K below the outside

temperature. Where higher temperature differentials persist there would be a risk of catching a

cold, as summer clothing would generally not be suitable for such ambient conditions.

For the annual hours at full utilisation in cooling operation, see the following tables.


6

Table 2 Hours at full utilisation /7/

Type of building Hours at full utilisation [h/p.a.]

cooling operation

Office building 300 - 400

Hospitals 800

Department stores 600 - 800

Trade fairs 500 - 600

Theatre/Cinema 200 - 300

Hotels 400 - 500

Apartments 100 - 200

BASES

7

2 BASES

The increasing demand for comfort has resulted in an increasing number of apartments being

equipped with cooling systems. At low energy consumption, these provide excellent ambient

comfort in most cases.

2.1 Air-conditioning, cooling and tempering

Air-conditioning of rooms means that the air temperature, as well as the relative humidity, is

regulated. Controlling the relative humidity requires a humidifying/de-humidifying system,

where the air is regulated to the required parameters using a cooler, a humidifier and a heater.

Conventionally, this is only done in centralised air-conditioning systems, where air acts as heat

transfer medium. Systems for the cooling of rooms to a specified temperature level generally

only require the air to be dehumidified. For this, fan convectors and ceiling cassettes with

condensate drain are used, where the water contained in the air condenses on the cooling

surfaces. Tempering describes the lowering or raising of the ambient temperature by a few

Kelvin. However, this does not result in any dehumidification. That is possible with heat transfer

above the dew point temperatures, for example via wall or underfloor heating systems or

cooling ceilings. In apartment buildings and smaller commercial operations, cooling and

tempering are the conventional method for increasing comfort levels.

Heat pumps enable both heating and cooling. In heating mode, heat pumps extract the heat

stored in the environment (underground, air, groundwater or surface water) and raise that

energy by means of a compressor to a higher temperature level that makes it useful for DHW

heating or for heating the building. In cooling mode, the heat transfer operates in reverse. Heat

is extracted from the building and transferred to the environment.

2.2 Passive and active cooling

When cooling a building with heat pumps, we differentiate between passive and active cooling.

The main difference between these methods is the operation with (active) or without (passive) a

compressor. In addition, refrigerant distribution systems are generally filled with antifreeze.

Where there is no risk of frost with passive cooling, water flows through the refrigerant

distribution systems, i.e. area heating, cooling ceiling or fan convectors. With active cooling, the

heating circuit contains a water:glycol mixture (brine).

Passive cooling is only possible when the heat source temperature lies below the required

cooling temperature. This can be assumed to be approx. 18 °C for underfloor heating systems

and 7 to 13 °C with fan convectors.

BASES

8

Active cooling is required when the heat source temperature lies above the required cooling

temperature.

Table 3 Main characteristics of passive and active cooling

Passive cooling Active cooling Compressor OFF Compressor ON Water in the distribution system Water:glycol mixture (brine) in

the distribution system

Heat source temperature lower than

the required cooling temperature

Passive cooling is also referred to as quiet or natural cooling; active cooling as dynamic cooling.

2.2.1 Passive cooling

With passive cooling, heat is transferred from the cool source via heat exchanger to the area

heating system or the fan convectors. The flow temperature is approx. 15 to 20 °C, and the

possible cooling capacity is limited to approx. 25 to 50 W/m². With area cooling, the cooling

water temperature must be above the dew point temperature. Otherwise condensate may form

on the heat exchanger surfaces.

Only pipes and fittings made from corrosion-resistant materials may be used. All supply lines

entering the house must be insulated in a vapour diffusion-proof manner to prevent the

formation of condensate.

2.2.2 Active cooling

The active cooling operates according to a principle similar to air-conditioning systems, where

the heat from within a building is extracted via the active refrigerant circuit and is then

transferred to low temperature "heat sink". Active cooling can be brought about by two different

means:

Method 1: Swapping the connections of the heating and heat source circuit at the heat pump

evaporator and condenser via suitable hydraulic equipment.

The heating circuit is routed to the heat pump evaporator and the source circuit to the heat

pump condenser. The heat pump compressor will be started, i.e. it is "active". The heat pump

can be changed over between heating and cooling via corresponding diverter valves. In

practical applications, this can only be brought about with brine|water heat pumps.

Method 2: Reversing the refrigerant circuit (reversible heat pumps).

The refrigerant circuit can be reversed. For this, the flow direction of the refrigerant is crucial.

The position of a 4-2-way valve determines the order of the components through which the flow

BASES

9

is routed. By changing the valve position, the evaporator and condenser functions are swapped,

and the operating mode changed between generating heat and cooling.

Figure 2 Operating mode of a brine|water heat pump with passive and active cooling function

Possible cooling distribution systems are fan convectors and ceiling cassettes.

Cooling ceilings and area heating systems are unsuitable for active cooling due to the low flow

temperatures. For example, cooling ceilings should not be operated with flow temperatures

below 15 °C.

The cooling capacity will not be rated at more than 60 W per m² heat transfer surface due to

considerations of personal comfort.

2.2.2.1 Comparison between active cooling using hydraulic changeover and a reversible

heat pump

The advantages and disadvantages of these two types of active cooling with heat pumps are

compared in the following table.

BASES

10

Table 4 Advantages and disadvantages - Hydraulic changeover and reversible heat pump

Cooling via hydraulic changeover Reversible heat pump

Advantages - Passive cooling is also possible, higher

efficiency

- Simultaneous cooling and DHW heating

possible

- Marginally better efficiency in the

refrigerant circuit

- Standard device can be used; optional

retrofitting (do not forget the thermal

insulation of existing pipe runs!)

- Lower pressure drop in the

heating circuit

- Lower investment outlay

Disadvantages - More material required (four diverter

valves); consequently more susceptible

- Higher pressure drop in the heating circuit

- Significantly higher installation effort and

space requirement

- Only active cooling is possible

- Either cooling or DHW heating

2.3 Heat cooling sources

Groundwater and ground probes are likely heat sources/heat sinks for passive cooling. Sources

for active cooling are ground probes, ground collectors and, to a limited extent, groundwater.

When cooling with reversible heat pumps, air or groundwater can be used as heat source/sink.

Table 5 Conventional natural heat sink systems for cooling with heat pumps [4]

Passive cooling Active cooling

Ground probe 8 – 12 °C Ground probe 8 – 12 °C

Groundwater 8 – 12 °C Ground

collector

0 – 15 °C

Outside air -20 - +35 °C

2.3.1 Ground probes

Passive cooling with ground probes utilises the constant temperature (approx. 10 °C) of the

ground at greater depths. The cooling capacity is sufficient for conventional residential

buildings and the assumption of a few cooling days per annum. Where high cooling loads are

present, the temperature underground gradually rises, resulting in a drop of the available

cooling capacity. Ground probes are suitable for passive and active cooling. For passive cooling,

the probes will be sized for 80% of the cooling extract capacity. For cooling operation it is

recommended to drill for shorter probes (max. 100 m).

Subject to application, size the probe for the heating or cooling case. In particular with high

internal cooling loads that may, for example, result from the presence of many occupants in the

BASES

11

building, the cooling demand may be greater than the heating energy demand. Cooling with

ground probes in summer also regenerates the heat source for winter.

Table 6 Average temperatures underground

Drilling depth

[m]

Average temperatures underground [°C]

Exposed site Urban area Height

0 9.5 9.5 3.2

25 11.3 12.5 8.0

50 12.0 13.5 8.7

75 12.8 14.5 9.5

100 13.5 15.5 10.2

125 14.3 16.5 11.0

150 15.0 17.5 11.7

175 15.8 18.5 12.5

200 16.5 19.5 13.2

2.3.2 Ground collectors

Ground collectors have only a limited use for passive cooling. Active cooling is possible.

With passive cooling, the ground heats up quickly reducing the temperature differential

between the ground temperature and the room temperature to an unacceptable level. In

addition, the ground temperature near the surface is substantially dependent on the outside

temperature. Should the temperature there exceed 15 °C, passive cooling could no longer be

achieved (see Figure 3).

The collector is well suited to active cooling, as in cooling mode; the ground has a substantially

lower temperature than the ambient air, thereby enabling the limit temperatures (10 - 60 °C) to

be maintained without difficulties. Furthermore, the CoP is higher than with systems using air

as heat sink. The drying out of the ground would be one disadvantage when using ground

collectors for active cooling.

The collector will be sized only for the heating operation.

BASES

12

Figure 3 Temperature progression underground

2.3.3 Groundwater

Both passive and active cooling are possible with groundwater as heat source.

Observe that the groundwater returned underground must not exceed a temperature of 20 °C. A

water analysis should also verify that the water is compatible with the heat exchanger material.

The average groundwater temperature in cooling mode is approx. 10 to 15 °C. Active cooling is

generally not required because of the low and stable temperature.

2.3.4 Air

With a reversible air|water heat pump, the outside air can be used as heat sink.

For this, the cooled air is transferred to the rooms to be cooled via fan convectors. There are no

further requirements of the source side. The heat source temperature determines the limits.

Table 7 Application limits reversible air|water heat pump

Outside air temp. Flow temp.

Min. Max. Min. Max.

Heating –20 °C 35 °C 18 °C 60 °C

Cooling 15 °C 40 °C 7 °C 20 °C

2.4 Distribution systems

The cooling operation is possible via an area (underfloor heating system, ceiling) or via fan

convectors (with condensate drain).

Heat is dissipated via an additional heat exchanger that, in cooling mode, receives a flow of

brine via a three-way valve. In heating mode, this is generally supplied constantly in series with

the condenser whilst the pump is running.

BASES

13

Apart from selecting the distribution system it requires careful consideration which rooms

actually require cooling in summer. It is, for example, conventional not to include the

bathroom, toilet and kitchen into the cooling cycle. Rooms requiring cooling include: Working,

living and bedrooms.

2.4.1 Area heating (underfloor)

The cooling capacity for cooling with area heating systems can be up to 25 W/m². However, this

may be significantly higher if the area heating system is subject to direct solar irradiation.

The cooling capacity is limited since, according to DIN 1946-2, a room temperature should not

exceed 21 °C at 0.1 m height when operating an underfloor heating system in cooling mode. /6/

When sizing the underfloor heating system for cooling, select a smaller pipe spacing than

would be conventional for heating purposes. The following applies to both heating and cooling

cases: The better the thermal insulation of the building the higher the pipe spacing can be with

identical flow temperatures.

The following summarises a number of climatic, economic and architectural benefits of area

cooling:

- High comfort level

- No draughts

- Quiet operation

- Low investment outlay

- Low operating costs

- Unrestricted interior design

Monitoring the relative humidity is beneficial, to prevent the formation of condensate on the

cooling surfaces. Check with the respective parquet manufacturer, whether this kind of floor

surface is compatible with a cooling operation.

Figure 4 Method of laying an underfloor heating system

2.4.2 Area heating (ceiling)

No minimum air temperatures need to be taken into consideration. Consequently, the cooling

capacity of a cooling ceiling can be substantially higher than that of an underfloor heating

system used for cooling. As a result, specific cooling capacities between 40 and 100 W/m² are

H-X DIAGRAM AND DEW POINT TEMPERATURE

14

possible, whereby the flow temperature represents the limiting variable. The minimum flow

temperature for cooling ceilings is 15 °C (manufacturer's details).

Figure 5 System image, cooling ceilings

2.4.3 Fan convectors and ceiling cassettes

The cooling capacity of fan convectors and ceiling cassettes is subject to the size of the building,

the air flow rate and the cooling water temperature. The larger and more powerful the device,

the higher its cooling capacity, but also the air flow rate and the air velocity. To prevent the

comfort limits specified by the DIN 1946 being exceeded, the cooling capacity should be

between 30 and 60 W per m² heat transfer surface of the fan convector.

The pipelines for the fan convectors and ceiling cassettes must be installed vapour diffusion-

proof. Pipelines embedded into walls cannot be used for connection to fan convectors as they

are not vapour diffusion-proof.

Figure 5 Fan convector and ceiling cassette

The distribution system for active cooling with fan convectors or ceiling cassettes is filled with

water:glycol mixture (brine). Consequently, the resistance of the individual components to brine

must be checked out. Brine can only be topped up as ready-mixed solution.

Please note: It is prohibited that the heating circuit is filled with potassium carbonate.

3 H-X DIAGRAM AND DEW POINT TEMPERATURE

Mollier best depicts the change in condition non-cooled rooms/cooled rooms in the so-called

h-x diagram.

In the following simplified diagram, temperature, relative humidity and absolute humidity are

depicted.


15

It is assumed that the non-cooled room has a temperature of 26 °C and a relative humidity of

65 % (point 1).

If the room is cooled by, for example 4 K by passive or active cooling (cooling to above the dew

point = above the saturation line), draw a vertical line down from point 1 to the 22 °C

isothermal line1 (point 2). Now the temperature of the cooled room is 22 °C with a relative

humidity of 80 %. This demonstrates clearly that the relative humidity increases when the room

is cooled.

If the cooling reaches below the saturation line, a different condition occurs and condensate is

produced.

Figure 6 Change of condition room cooling /3/

1 Isothermal lines: Lines of constant temperature


16

The dew point temperature subject to the air temperature and relative humidity can also be

checked in the h-x diagram. The dew point temperature for condition 2 can be checked on the

Y-axis, if the vertical line from point 1 to point 2 is extended to the saturation line. In that case it

is 18.4 °C.

Working with the following table enables a precise and more convenient determination of the

dew point temperature.

Table 8 Dew point temperature

COOLING WITH BRINE|WATER HEAT PUMPS

17

4 COOLING WITH BRINE|WATER HEAT PUMPS

4.1 Sizing

The ground probes are sized according to the heat pump heating output. The resulting cooling

capacity is illustrated in the following table. Where higher cooling capacities are required,

install a correspondingly greater number of probes.

Table 9 Sizing table ground probe

Heat pump type Heating

output

(0/35) [kW]

Refrigeration

capacity

[kW]

Ground

probe

32 x 2.9

No.

Ground

probe2

32 x 2.9

Depth [m]

Cooling

capacity

[kW]

WPC 5 cool 5.8 4.5 1 pce. 82 3.2

WPC 7 cool 7.8 6.0 1 pce. 109 4.2

WPC 10 cool 9.9 7.7 2 pce. 70 5.4

WPC 13 cool 13.4 10.3 2 pce. 94 7.2

WPF 5 5.8 4.5 1 pce. 82 3.2

WPF 7 7.8 6.0 1 pce. 109 4.2

WPF 10 9.9 7.7 2 pce. 70 5.4

WPF 13 13.4 10.3 2 pce. 94 7.2

WPF 16 16.1 12.5 3 pce. 84 9.6

4.2 WPF operating modes

4.2.1 Heating mode WPF

Environmental energy is extracted from the ground via the heat exchanger on the heat source

side. The absorbed energy together with the energy used to drive the compressor is transferred

to the heating water by the heat exchanger on the heating water side. The domestic hot water is

heated via the indirect coil integrated into the DHW cylinder.

2 Condition: Approx. 55 W/m extraction capacity.


18

4.2.2 Passive cooling operation with WPF

The brine circulates in cooling mode via the additional heat exchanger. Consequently, heat is

transferred from the hotter to the colder medium. The heating water of the area heating system

or the cooling ceiling cooled by this method flows through the floor/ceiling of the rooms to be

cooled and thereby lowers the area temperature of the floor/ceiling. The compressor will only

be started if DHW is required. The water at the higher temperature level flows directly into the

indirect coil of the DHW cylinder.

The cooling operation remains switched off during DHW heating.

4.3 WPC cool operating modes

4.3.1 Heating mode WPC cool

Environmental heat is extracted from the ground via the heat exchanger on the heat source

side. Any energy extracted is transferred, together with the energy drawn by the compressor

drive, to the heating water by the heat exchanger on the heating water side. The DHW is heated

via the internal indirect coil inside the DHW cylinder. The DHW cylinder is integrated into the

WPC cool.

4.3.2 Passive cooling operation with WPC cool

The brine circulates in cooling mode via the additional heat exchanger. Heat is transferred from

the hot to the cold medium. The heating water of the area heating system or cooling ceiling

cooled by this process flows through the floor/ceiling of the rooms to be cooled, thereby

lowering the temperature of the floor/ceiling. The compressor will only be started if DHW is

required. The water at the higher temperature flows directly into the indirect coil of the DHW

cylinder.

The cooling operation remains switched off during DHW heating.

4.4 Active cooling operation WPF and WPC

Active cooling requires the cooling module WPAC 1 (with integral brine circulation pump) or

WPAC 2 (without integral brine circulation pump). The modules are comprised of the following:

Four 3-2-way valves switch the circulation over between heating, passive and active cooling

subject to demand.

Cooling with the WPAC is controlled in two stages from passive to active cooling.

1. Stage: Cooling through running source pump.

2. Stage: Cooling though running source pump and running compressor.

Stage 2 will be added if, after cooling at stage 1 for 30 minutes, the actual flow temperature is

still higher than the required flow temperature.


19

Figure 6 WPAC 1 layout for WPF (l.h.) and WPAC 2 for WPC (r.h.)

The WPMi heat pump manager controls the system.

Active cooling is currently only possible with fan convectors or ceiling cassettes.

4.4.1 Minimum flow rate for active cooling

The minimum flow rate on the side to be cooled corresponds to the minimum flow rate in

heating mode. The minimum flow rate on the source side in cooling mode must be halved,

relative to the minimum flow rate on the source side in heating mode.

The following applies: Cooling side (inside the building): heatingcooling VV min,min,&& =

Source side: heatingcooling VV min,min, 5,0 && ⋅=

4.5 Valve positions

4.5.1 Passive cooling

During passive cooling, brine is routed via changing the valve positions so that the brine cooled

by the ground flows directly into the fan convector. The evaporator must receive a volume flow

on account of the pipework, without the compressor running. The return from the fan

convectors is routed through the condenser back outside again into the ground probes.

4.5.2 Active cooling

With active cooling, the valves are positioned so that the heating water leaving the fan

convector is routed through the evaporator and the brine circuit of the ground probes through

the condenser.

The heating water leaving the fan convector must be routed through the evaporator to extract

the heat from the heat transfer medium. The compressor will be running.

The source pump is adequate for cooling operation up to the brine|water heat pump WPF 13.

For heat pumps with a higher output range, a second, additional source pump or a low loss

header is required.


20

4.5.3 Cooling and DHW demand

For active cooling, we need to differentiate between the two possible cooling stages. The

cooling output is immediately switched off in case of DHW demand, and DHW heating is

activated if the system is in cooling mode stage 1 (source pump ON, compressor OFF).

In cooling mode stage 2 (source pump ON, compressor ON), cooling and DHW heating can

operate in parallel. The cooling output is, in that case, only switched off if the required flow

temperature and the set room temperature are achieved.

Figure 7 Operating mode of a brine|water heat pump with passive and active cooling function


21

4.6 Hydraulics WPF

Figure 8 Hydraulic diagram - Heating with WPF without WPAC 1

Figure 9 Hydraulic diagram - Passive cooling with WPF without WPAC 1

Legend:

TA = Temperature sensor

outside


flow


return

TW = Temperature sensor

DHW

FEK = remote control with

room temperature and

humidity sensor


22

4.7 Hydraulics WPF with WPAC 1

Figure 10 Hydraulic diagram - Heating with WPF and WPAC 1

Figure 11 Hydraulic diagram - Passive cooling with WPF and WPAC 1

Figure 12 Hydraulic diagram - Active cooling with WPF and WPAC 1

Legend:

TA = Temperature sensor outside

TM = Temperature sensor mixer

TR = Temperature sensor return

TW = Temperature sensor DHW

FE7 = Remote control with room

temperature sensor

FEK = Remote control with room

temperature and humidity sensor


23

4.8 Hydraulics WPC cool

Figure 13 Hydraulic diagram - Heating and cooling with WPC cool without WPAC 2 Key:





24

4.9 Hydraulics WPF with WPAC 2

Figure 14 Hydraulic diagram - Heating with WPC and WPAC 2

Figure 15 Hydraulic diagram - Passive cooling with WPC and WPAC 2

Figure 16 Hydraulic diagram - Active cooling with WPC and WPAC 2

Key:


TM = Temperature sensor mixer

TR = Temperature sensor return

TW = Temperature sensor DHW

FE7 = Remote control with room

temperature sensor



COOLNG WITH WATER|WATER HEAT PUMPS

25

5 COOLNG WITH WATER|WATER HEAT PUMPS

5.1 Sizing

The volume of groundwater that can be utilised to remove heat is determined in accordance

with the volume of groundwater required by the heat pump.

The temperature differential between the groundwater and the cooling water is approx. 5 K.

The average groundwater temperature in cooling mode is approx. 15 °C.

Table 9 Sizing table groundwater

Heat pump type Cooling output Groundwater

volume3

WPW 7 5.9 kW 1.5 m³/h

WPW 10 8.2 kW 2.1 m³/h

WPW 13 10.2 kW 2.6 m³/h

WPW 18 14.1 kW 3.4 m³/h

WPW 22 M 18.2 kW 4.4 m³/h

5.2 Operating modes

5.2.1 Heating operation

Heat is extracted from the groundwater via the heat pump heat exchanger on the heat source

side. Any energy extracted is transferred, together with the energy drawn by the compressor

drive, to the heating water by the heat exchanger on the heating water side. The heating water

is routed via the buffer cylinder into the underfloor heating system and the indirect coil in the

DHW cylinder.

3 The system will be sized for heating operation. If required, a higher cooling capacity can be achieved with a

larger well pump.

COOLNG WITH WATER|WATER HEAT PUMPS

26

5.2.2 Passive cooling operation

The cool groundwater is routed through the additional heat exchanger when cooling is

required. Heat is transferred from the hotter to the colder medium. The heating water of the

area heating system or cooling ceiling cooled by this process flows through the floor/ceiling of

the rooms to be cooled, thereby lowering the temperature of the floor/ceiling. The cooled

heating water can also be routed through a fan convector or ceiling cassettes. The compressor

will only be started if DHW is required. The water at the higher temperature flows directly into

the indirect coil of the DHW cylinder.

The cooling operation is switched off during DHW heating.

5.2.3 Active cooling operation

Theoretically at least, active cooling is possible with a reversible water|water heat pump. Active

cooling using hydraulic changeover is not feasible.

COOLING WITH AIR|WATER HEAT PUMPS

27

6 COOLING WITH AIR|WATER HEAT PUMPS

Information regarding the sizing, operating modes and the hydraulic layout for active cooling

with reversible air|water heat pumps will be available mid 2007.

SETTING PARAMETERS OF AND CONTROL WITH THE WPMi

28

7 SETTING PARAMETERS OF AND CONTROL WITH THE WPMi

The cooling operation can only be regulated with the heat pump manager WPMi. The WPMi is

fitted as standard to the following heat pumps: WPC, WPC cool, WPF with integral controller

and WPW with integral controller. Currently, the WPM II offers no cooling function.

In addition, the operation requires the analog remote control unit with room temperature

sensor FE 7 or the digital remote control unit FEK with room temperature sensor and humidity

sensor.

A separate remote control unit is required for each circuit in systems with two heating circuits.

Cooling via heating surfaces is only possible with the FEK.

Figure 17 FE 7 and FEK (from left to right)

For cooling, the heat pump manager WPMi must be in Summer mode. The changeover from

heating mode to summer mode is subject to the outside temperature.

Three adjustable parameters are available for the summer mode. Summer mode 1 for lightly

built constructions. In this mode, the average outside temperature is calculated over a period of

24 hours. In this mode, the average outside temperature is calculated over a period of 48 hours.

In this mode, the average outside temperature is calculated over a period of 72 hours.

The heat pump automatically changes over to summer mode if the average outside temperature

is higher than 20 °C. The freely selectable standard setting was factory-set to summer mode 1

and a changeover at 20 °C.

The outside temperature from which the changeover from heating to summer mode occurs, can

be reduced by up to 1 °C. For this, the outside temperature must be higher than the selected

value.

The heat pump manager is in summer mode, if the heat pump stops and restarts again straight

away after the outside temperature value has been changed. This enables a check during

commissioning whether the changeover from winter to summer mode functions correctly.


29

7.1 Standard settings

Control unit setting parameters for cooling:

- Set room temperature

- Flow temperature

- Flow temperature hysteresis (in this case a "+ hysteresis")

- Dynamic

Table 10 Standard setting and setting ranges for the WPMi

Standard setting Setting range

Set room temperature 25 °C 20 °C - 30 °C

Flow temperature 15 °C 10 °C – 25 °C

Flow temperature hysteresis 5 K +1 K – +5 K

Dynamic 10 1 - 10

7.2 Set room temperature

For cooling, the set room temperature should be changed subject to the outside temperature.

Generally, with cooling, the internal temperatures should only be approx. 3 to 6 K below the

outside temperature (relative to a setting range of 22 - 26 °C).

7.3 Flow temperature

Apart from the set room temperature, the customer can also change the flow temperature.

Recommendation:

- Floor tiles, flow temperature 20 °C,

- Carpet, flow temperature 15 °C,

A lower flow temperature must be selected for fitted carpets, as the heat transfer coefficient of

carpeted floors is lower than that of tiles.

7.4 Flow temperature hysteresis

The control circuit requires a hysteresis to prevent a counter-action when minute control

deviations occur. The hysteresis specifies the possible deviation from the set value.

For a system with slow responses, the recommended setting of the hysteresis subject to the heat

transfer coefficient is: Small hysteresis (2 K), and large hysteresis (5 K) for a system with quicker

responses.

The heat transfer coefficient describes the resistance of a material to thermal conduction and is

therefore a measure for the speed of the heat transfer, in this example of heating water to the

floor surface.


30

Table 11 Recommended values for flow temperature and flow temperature hysteresis

Flow temp. [°C] Hysteresis [K]

Parquet 15 2

Laminate 15 2

Natural

stone

20 4

Carpet 15 2

Cork 15 1

Marble 20 5

Clay 20 4

7.5 Dynamic (active cooling only)

The dynamic parameter enables a choice to be made as to how quickly the compressor is

started in case of active cooling. Values between 1 and 10 can be selected.

Quick reacting system

The dynamic, set to 1, switches the compressor ON as soon as the source pump has been running

for 10 minutes and the current flow temperature is higher than the selected flow temperature

plus the flow temperature hysteresis plus 0.5 K (hysteresis for the dynamic of value 1).

Slow reacting system

The dynamic set to 10 switches the compressor ON after the source pump has been running for

30 minutes and the current flow temperature is higher than the selected flow temperature plus

the flow temperature hysteresis plus 2 K (hysteresis for the dynamic of value 10).

Interpolation is applied between the values 1 and 10.

7.6 Control characteristics of the passive cooling

The cooling mode is started when the actual room temperature is ≥ 25 °C. The heating circuit

pump and the control unit cooling output are switched ON. For the first 60 seconds, only the

heating circuit pump is enabled.

7.6.1 Source pump

The source pumps starts when the control variable is smaller than the actual flow temperature.

The control variable is different for each distribution system.


31

7.6.1.1 Fan convectors

For fan convectors, the control variable is equal to the selected flow temperature. The following

applies: Control variable = selected flow temperature

7.6.1.2 Heating surfaces

The dew point of the heating surfaces is also monitored.

Control variable = selected flow temperature if the selected flow temperature + hysteresis >

dew point temperature + 2 K (see example case 1)

Control variable = dew point temperature + 2 K if the selected flow temperature + hysteresis

< dew point temperature + 2 K (see example case 2)

Here is an example by way of an explanation:

The user has selected a flow temperature of 15 °C plus a flow temperature hysteresis of 5 K. As

a result a flow temperature of 20 °C is calculated.

Case 1: Relative humidity in the room: 75 %

The dew point temperature at 20 °C and a relative humidity of 75 % is 15.4 °C (see Table 8);

15.4 °C + 2 K = 16.4 °C

16.4 °C < 20 °C: Control variable = selected flow temperature + hysteresis = 20 °C

Case 2: Relative humidity in the room: 90 %

This results in a dew point temperature at 20 °C and 90 % relative humidity of 18.3 °C.

18.3 °C + 2 K = 20.3 °C

20.3 °C > 20 °C: Control variable = dew point temperature + 2 K + hysteresis = 18.3 °C + 2 K

+ 5 K = 25.3 °C

Independent of the flow temperature, the source pump must run for at least 5 minutes. This

ensures that at least once, only cool water enters the cooling system to achieve a cooling effect

at all.

At a flow temperature < 15 °C, the source pump switches OFF subject to the standard settings.

If, during this minimum runtime of 5 minutes, DHW heating is demanded, the cooling mode

immediately switches over to DHW heating.

7.7 Control characteristics of the active cooling

The active cooling is controlled in the same way as passive cooling and is only supplemented by

starting of the compressor and a simultaneous changeover of the valves.


32

7.7.1 Compressor

If, after 30 minutes of passive cooling (the source pump has been running for 30 minutes), the

actual flow temperature is still higher than the control variable plus hysteresis, the compressor

starts and the valves change over.

The compressor switches OFF if the room temperature is lower than the set room temperature –

2 K.

In this case, the 2 K is a fixed control hysteresis that should not be confused with the flow

temperature hysteresis.

BRINE RESISTANCE

33

8 BRINE RESISTANCE

With active cooling, fill the distribution system with a water:glycol mixture (brine). Therefore

ensure that the individual components concerned are resistant to brine. Brine must only be

topped up with a ready-mixed solution.

If the system is run with brine expect a 1.5-fold pressure drop.

If the correct glycol:water concentration was filled into the system and the brine contains

corrosion inhibitors (25 to 33 %), then the following components from the Stiebel Eltron product

range are brine resistant:

- Pumps

- Valves

- Expansion vessels

- Safety valves

Overflow valves, the seals of which are made from PTFE, are suitable for water:glycol mixtures

without restrictions.

When selecting the pump, ensure that only cast pumps (condensate forming between the casing

and the stator) or rotary pumps are used.

The expansion vessel on the brine side may possibly be sized larger in brine|water heat pumps

in cooling mode on account of the temperature differentials.

Table 12 Possible temperature differentials during heating and cooling

Temperature

differentials

Heating 5 – 15 °C

Passive cooling 5 – 25 °C

Active cooling 5 – 50 °C

WIRING CHANGEOVER COOLING MODE

34

9 WIRING CHANGEOVER COOLING MODE

9.1 Wiring diagram

Figure 18 Hydraulic diagram WPF

Figure 19 Connection diagram WPF


35

Figure 20 Hydraulic diagram WPC cool

Figure 21 Connection diagram WPC cool


36

Figure 22 Hydraulic diagram - Cooling WPF with WPAC 1

Figure 23 Connection diagram - WPF with WPAC 1


37

9.2 Distribution strip/zone valve

For the changeover from heating to cooling mode with area heating systems and the associated

opening of actuator valves in the heating circuits in the rooms to be cooled, special distribution

strips are available.

Such distribution strips enable the connection of room temperature controllers and actuators in

the individual rooms. In addition, they are equipped with an input for changing over between

cooling and heating mode.

Figure 24 Distribution strip heating/cooling

The following overviews explain how the wiring of the rooms that require cooling and those

that do not should be carried out.


38

Figure 25 Connection diagram for the wiring of the distribution strip with room thermostat

1 Room thermostat, heating only 2 Room thermostat, heating and cooling 3 Valves, room 1 K Cooling H Heating L Phase N Neutral conductor


39

Figure 26 Example of a connection diagram for the wiring of the distribution strip

1 SP cool distributor strip 2 Room 1, heating and cooling 3 Room 2, heating and cooling 4 Room 3, heating only 5 Single room thermostat (on site) 6 FEK digital remote control 7 Heating circuit distributor 8 WPMi heat pump manager

COMPARISON COOLING WITH DIFFERENT HEAT PUMPS

40

10 COMPARISON COOLING WITH DIFFERENT HEAT PUMPS

The advantages and disadvantages of the heat pump types for use in passive and active cooling

are compared in the following table.

Table 13 Overview of the advantages and disadvantages

Brine|Water heat pump Water|Water heat pump Reversible Air|Water heat

pump

Advantages - Passive and active

cooling are possible

- Low flow temperature

possible (active cooling)

- Low operating costs as

only the brine

circulation pump

operates (in passive

cooling)

- Passive cooling adequate

due to constant heat

source temperature

- Constant flow

temperature

- Low operating costs as

only the well pump

operates (in passive

cooling)

- Low installation costs

for the heat source

- Flow temperatures up

to 7 °C possible

Disadvantages - High installation costs

for the heat source

- Flow temperature

subject to the ground

probe temperature (in

passive cooling)

- High installation costs for

the heat source

- Check the heat

exchanger compatibility

with groundwater

- Cooling only possible

from outside

temperatures of 15 °C

- Only active cooling is

possible

- High operating costs as

pumps and compressor

operate

In summary it can be said that, with a brine|water heat pump passive and active cooling is

feasibly. With a water|water heat pump, passive cooling may frequently be adequate. With

reversible air|water heat pumps, only active cooling is technically feasible.

ALTERNATIVE SYSTEMS AND COST CONSIDERATIONS

41

11 ALTERNATIVE SYSTEMS AND COST CONSIDERATIONS

11.1 VRF systems, air-conditioning systems with direct evaporation

Split air-conditioning units are an alternative to the extraction of cooling loads. In such

equipment, condensate is created when cooling the air; this must be drained away. One

disadvantage is the additional installation effort (internal and external equipment, wall outlets),

which is not required for cooling with an existing area heating system.

11.2 Free cooling

Free cooling represents an alternative that requires no mechanical drive for cooling the

buildings. This can be easily realised if the room to be cooled is equipped with ventilation

openings in opposing walls (windows, ventilation flaps). This enables effective night ventilation

by cross venting. The cooling capacity is hampered by the low temperature differential between

day and night temperatures, particularly on hot days. The specific cooling capacity is approx. 1.5

to 2.5 W/(m³/h). /5/

Free ventilation is easily achieved with domestic ventilation systems.

11.3 Air duct

Apart from fan convectors or area heating systems there is the possibility of utilising air ducts in

existing domestic ventilation systems as an alternative distribution system for cooling purposes.

For this, a corresponding heat exchanger can be integrated into the central ventilation unit. One

problem, however, is that pure cooling raises the relative humidity, resulting in the

temperature falling below the dew point and consequently in condensation. Cooling/tempering

is therefore unacceptable for hygienic reasons. However, air-conditioning with dehumidification

would be feasible.

A classic office air-conditioning system, where the offices are air-conditioned with treated air,

contains several banks for treating the air. There are units for humidifying and dehumidifying

the air as well as those for boosting the heating. In other words, these units do not provide a

simple cooling of the air. Also, these units are serviced regularly.

11.4 Water wall

Water walls represent a simple option for reducing the room temperature in summer. If the

circulating water is cooled below the dew point, condensate is created on the water surface,

making the water wall suitable for dehumidification and cooling.


42

11.5 Cost consideration

Today, buildings are almost always cooled with split air-conditioning units, chillers or VRF

systems (variable refrigerant flow). The alternative, i.e. the use of heat pumps for cooling

purposes, has come to be considered recently as heat pumps have found increasing favour as

heating system. The heat pump has become a favourite heating system since oil and gas prices

have constantly risen in cost. The additional use for cooling or tempering is attractive because

of the low level of addition costs for the cooling systems and the very low costs for generating

the cooling capacity. The combined use for cooling and heating improves the efficiency of heat

pumps with ground probes in heating mode, as the ground probe significantly regenerates the

ground in summer.

The following cost consideration compares three typical application examples for cooling; these

are also shown in Table 14.

Example 1: Residential building 150 m² (cooling load 6 kW, 4 rooms, 150 hours at full cooling

utilisation)

Example 2: Office building 300 m² (cooling load 25 kW, 15 rooms, 400 hours at full cooling

utilisation)

Example 3: Shop 500 m² (cooling 45 kW, 700 hours full cooling utilisation)

Cooling foodstuffs with active or passive cooling is not feasible due to the limits of use, off

periods and control equipment.


43

Table 14 Cost comparison for different cooling systems using the examples of a residential building, an office building and a shop /1/

Heat pump


Room air-

conditioning

units

VRF-controlled

air-conditioning

systems

Performance factors in cooling mode 15.0 4 5.0 3.0 3.8

Example: Residential building 150 m² (cooling load 6 kW, 4 rooms, 150 hours at full cooling

utilisation)

Additional investment, cooling €2.000 €7.000 €9.000

Energy costs €9.0/p.a. €19.8/p.a. €45.0/p.a.

Annual cooling costs €268.0/p.a. €926.3/p.a. €1210.5/p.a.

Unusual

Example: Office building 300 m² (cooling load 25 kW, 15 rooms, 400 hours at full cooling utilisation)

Additional investment, cooling €4.000 €25.000 €30.000 €45.000

Energy costs €100.0/p.a. €220.0/p.a. €500.0/p.a. €395.0/p.a.

Annual cooling costs €618.0/p.a. €3457.5/p.a. €4385.0/p.a. €6222.5/p.a.

Example: Shop 500 m² (cooling 45 kW, 700 hours full cooling utilisation)

Additional investment, cooling €5.000 €27.000 €40.000

Energy costs €315.0/p.a. €693.0/p.a. €1243.0/p.a.

Annual cooling costs €962.5/p.a. €4189.5/p.a.

Unusual

€6423.0/p.a.

Assumptions for the cost consideration

- The investment outlay for the devices is based on manufacturer's details plus conventional installation

costs.

- For the additional costs in connection with the cooling with heat pumps it is assumed that a heat pump

heating systems with ground probes is already installed.

- The electricity tariff for active cooling with heat pump is €0.11/kWh.

- The electricity tariff for passive cooling with heat pump and cooling with room air-conditioning units and

VRF systems is €0.15/kWh.

- The annuity with an annuity factor of 12.95 % is based on an amortisation period of 10 years with an

interest rate of 5 %.

11.5.1 Recommendations

Given the energy and annual cooling costs, as well as the different cooling loads, we

recommend the use primarily of passive cooling in detached houses. In office buildings, passive

and active cooling and in small businesses primarily the active cooling is recommended.

4 Only the pump operation for the brine and heating circuit are taken into account, as the compressor operation is not

required.

COOLING LOAD CALCULATION FORM

44

Table 15 Overview application options passive/active cooling


Detached house Office building

Office building Small business

12 COOLING LOAD CALCULATION FORM

The cooling load activation form enables an estimate of the cooling load for one room

respectively to be made. The following influencing factors are taken into consideration:

- Cooling load due to solar irradiation through windows, skylights and doors

- Cooling load due to external and internal walls and floors

- Cooling load due to the ceiling

- Cooling load due to electrical devices

- Cooling load due to occupants

CHECK LIST

45

13 CHECK LIST

- What is the purpose of the heat pump?

- What heat source is to be used with the heat pump?

- What is the required cooling capacity? Carry out a cooling load calculation.

- What cooling source is available?

- Check the compatibility of the heat exchanger when cooling with a water|water heat

pump.

- All lines and fittings must be made from corrosion resistant material.

- Are all components resistant to brine?

- Are all pipe runs insulated in a vapour diffusion-proof manner?

- Must application limits be taken into consideration?

- The brine increases the pressure drop. This must be taken into account when sizing the

pumps; allow for a 1.5-fold pressure drop.

- Topping up with brine only as ready-mixed solution.

- The expansion vessel on the brine side may need to be sized larger for cooling since the

temperature differentials are greater.

- Use only a circulation pumps that are resistant to brine and condensate.

- Minimum flow rates, active cooling: On the cooling side: The same minimum flow rate as

for heating; on the source side: ½ the minimum flow rate as for heating.

The following applies: Cooling side (inside the building): heatingcooling VV min,min,&& =

Source side: heatingcooling VV min,min, 5,0 && ⋅=

BIBLIOGRAPHY

46

14 BIBLIOGRAPHY

/1/ Brugmann, Krone; Technische, energetische und wirtschaftliche Bewertung passiver und

aktiver Kühlsysteme mit Sole/Wasser-Wärmepumpen, published 4th Forum Wärmepumpen

2006, Berlin

/2/ Handbuch der Klimatechnik, vol. 1 Grundlagen, publisher C.F. Müller GmbH, Karlsruhe 1989,

chapter 3 Physiologische Grundlagen p. 62

/3/ h-x diagram, http://www.bosy-online.de/hx-diag.pdf (11/06)

/4/ Leusden, Freymark, Behaglichkeitsfeld; Der Gesundheitsingenieur, No. 72, 1951

/5/ Pfluger, Rainer; Technologien zur energieeffizienten Raumkühlung: passiv-hybrid-aktiv,

Energieeffiziente Raumkühlung, Protokollband 31

/6/ Recknagel, Sprenger, Schramek; Taschenbuch für Heizung und Klimatechnik, 2005/2006

72nd issue, Oldenbourg Industrieverlag Munich 2005, p. 1134 3.2.3-7 Kombinierter Kühl- und

Heizboden

/7/ Sponsel, Christian, Hilligweg, Arnd; Wirtschaftlichkeit von Eisspeichern, TGA Fachplaner

4-2003

KEYWORD INDEX

47

15 KEYWORD INDEX

Active cooling, 8

Air, 12

Air-conditioning, cooling and tempering, 7

Area heating (ceiling), 13

Area heating (underfloor), 13

Brine resistance, 34

Ceiling cassettes, 14

Comfort, 4

Comparison of cooling with different heat

pumps, 40

Cooling load calculation form, 44

Cooling via hydraulic changeover, 10

Cooling with air|water heat pumps, 28

Cooling with brine|water heat pumps, 17

Cooling with water|water heat pumps, 26

Distribution strip/zone valve, 38

Dynamic, 31

Fan convectors, 14

Ground collectors, 11

Ground probes, 10

Groundwater, 12

Hours at full utilisation for providing

cooling, 5

h-x diagram and dew point temperature, 14

Hydraulics WPC cool, 24

Hydraulics WPF, 22

Hydraulics WPF with WPAC 1, 23

Hydraulics WPF with WPAC 2, 25

Operating modes WPC cool, 18

Operating modes WPF, 17

Passive cooling, 8

Reversible heat pump, 10

WPMi, 29

handbuch

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