ThermoActive-Prefabricated-Slab by liwenting


									ThermoActive Prefabricated Slab
Comfort & performances for energy savings

Imagining and constructing tomorrow’s buildings is indeed a real chal-
lenge for designers. With an eye on achieving such a goal, energy per-
formance enhancement is beyond any doubt one of the key ideas.
Considering this, we have designed the thermo active prefabricated
slab, an innovation combining comfort, simplicity, and high-energy per-
The system integrates heating and cooling within the building structure,
more precisely on the lower part of the concrete slab.
This solution is ideal for energy efficient buildings, because it combines
the storage capacity of concrete with radiant ceiling high performance,
fusing them together.
The outcome is a starting low-cost solution, combining the quick execu-
tion and reliability of an industrialized product, made under quality and
control standards.
KaRo Solar
             Climatisation douce
Presentation                                      3

Purpose: high-energy performance buildings        4
Innovation                                        4
Buildings comfortable both in winter and summer   5
Cooling without refrigeration                     5
Radiant Ceiling                                   6
Thermodynamics Basic Concepts                     7
The radiant ceiling                               9
KaRo Systems Radiant Ceilings                     10
Thermoactive prefabricated slab                   12
Benefitting from Concrete Material Advantages     16
Inertia: Free Energy Accumulation                 17
Multiple Performances                             20
Service during Project Phase                      21
Performance during Work Phase                     22
Performance during Occupation Phase               23
Performances during Restructuring Phase           32
Comparative costs                                 33
Service and Support                               34
                                                   The thermoactive prefabricated concrete slab
Under most European environmental                  is a concrete slab solution, designed for all
agreements (Grenelle Law in France, etc.),         kinds of high-energy performance buildings
public or service buildings must qualify as        under low-consumption building standards,
low energy consumption buildings .                 and more precisely for:
In this context, some entrepreneurs
already try to achieve the highest energy            •	 Residential buildings
performance summit: Positive energy                  •	 Office Buildings
buildings (buildings with positive energy
                                                     •	 Hospitals
                                                     •	 Hotels
                                                     •	 Schools
From this viewpoint, RECTOR, a French
leader in the manufacturing of concrete              •	 Public buildings
products for construction, has set up a              •	 Jail buildings
partnership with KaRo Solar, a European
expert in radiation heating and cooling
We have brought our “Savoir faire” together
in order to develop and provide you with
a completely revolutionary solution: the
thermoactive pre-slab, a patented innovation
(French Patent No. 08/05703, European
Patent No. 09/356055.5).
A real structural and thermal solution that will
enable you to achieve the financial balance of
your eco-efficient building project.

4 |   KaRo
                                                       Thermoactive prefabricated concrete slab

BUILDINGS COMFORTABLE BOTH IN WINTER               The single A-C units have a very low cop These
AND SUMMER                                         systems are characterized by low consump-
                                                   tion (consumed energy and supplied power
Modern buildings should ensure thermal com-        ratio).. Consequently, the energy necessarily
fort during both winter and summer seasons,        consumed for cooling in summer is consider-
without failing to consider energy efficiency      ably higher than the energy necessarily con-
standards under new regulations.                   sumed for heating in winter.
In winter, comfort conditions are easier to        In addition, this kind of installation presents
achieve. Building energy efficiency is mainly      other problems:
controlled by thermal insulation, as avoiding
heat leaks is the main issue.                        •	 Require space in each roomsite
On the other hand, in summer time, comfort           •	 Uncomfortable sensation due to air drafts
conditions are more difficult to achieve, be-        •	 Poor control of temperature set point: a
cause generating cold is more difficult. Air            low temperature set point often results
conditioning systems usually report low per-            in sudden temperature changes and
formance and high energy consumption.                   even health problems (throat pain)
Therefore, cold ceiling systems are increas-         •	 High sound levels (fans noise)
ingly recommended, as they offer the advan-
                                                     •	 Health risk (existence of pathogenic or-
tage of requiring fairly cold water (16º C), al-
                                                        ganisms – legionella - or the need to
lowing to combine them easily with low energy
                                                        use chloride disinfectants)
consumption cold water productions. It’s easy
to find water at 16°C in the ground or in the        •	 Unfavourable carbon balance. These
sea. (see chapter 9 of our general documenta-           systems usually use HFC
tion)                                                •	 Considerable maintenance need (filter
COOLING WITHOUT REFRIGERATION                           change, cleaning, etc.)

Environmental Standards are restrictive con-         •	 Short life of China made products (5 to
cerning the use of refrigeration systems                8 years on average), coupled with ma-
through air conditioners.                               terial and refrigeration gas recycling

                                                                                   KaRo     | 5
Radiant Ceiling
A SOLUTION SUITABLE FOR THE BIO-                   Today thermal insulation standards and new
CLIMATIC CONCEPTION (ECO-CONCEPTION).              construction techniques are used in bio-
                                                   climatic architecture principles. In the same
A solution suitable for the bio-climatic con-
                                                   manner, they leave incandescent lighting sys-
ception (eco-conception).
                                                   tems aside, which reduces energy consump-
Because low consumption energy building is         tion necessary for cooling.
now the rule, radiant ceiling resort to be one
                                                   Radiant ceiling moderate nominal cooling ca-
of the solutions,efficient and competitive for
                                                   pacity is thus sufficient for ensuring effective
achieving this goal.
                                                   cooling during summer time in all European
Being a solution that has been recognized for      regions. The heating mode remains easier.
long for is high efficiency , the radiant ceil-
                                                   Cool ceiling capacity is enough for ensuring
ing are commonly used in Northern Euro-
                                                   cooling of an adequately insulated building .
pean countries, forerunners of high-energy
performance building construction.
This system is based on a natural phenom-
enon and allows providing comfort both in
summer and winter, putting old high energy
consumption air conditioning systems aside.
Radiant ceiling systems deliver a purely higher
performance than traditional systems.
They are in turn reversible systems providing
cold and heat at the same time.
The use of traditional air conditioning systems
(fan coil or V.A.V.) was mainly attributable to
their cooling capacity a priori higher than that
of radiant ceilings.

6 |   KaRo
                                                        Thermoactive prefabricated concrete slab

Thermodynamics Basic Concepts
RADIATION & CONVECTION                              RADIATION
Thermal exchanges derive from the tempera-          Any body sends out a radiation power
ture difference between two elements. They          P=σεST4, where σ refers to a physical con-
can be driven by 3 mechanisms:                      stant; S refers to the body surface; ε refers to
                                                    the emissivity coefficient (depending on each
  •	 By radiation between two surfaces.             material), and T refers to the absolute tem-
  •	 By convection caused by air move-              perature (=T in °C + 273.15).
     ments between two hot/cold sources             Bodies absorb radiations sent out around
     (human body, walls, windows etc.)              them, so that two elements at different tem-
  •	 By conduction between two elements             peratures exchange energy from the hot ele-
     in contact or within one.                      ment to the cold one .
The exchanges between a person and an air           This exchange occurs spontaneously, requir-
conditioned room are mainly governed by con-        ing no intervention: radiation can be produced
vection and radiation. Conduction only has an       in vacuum . This is the way we get heat from
influence on the energy storage and on the          the sun.
heating/cooling of the emitting surfaces..
                                                    In the case of a radiant ceiling, this exchange
CONVECTION:                                         occurs directly between the ceiling and the
Convection is an energy exchange deriving           occupants. Neither cooling nor ventilation are
from air circulation. This exchange may be          necessary, which results in important energy
natural (hot air rises, so that there is a sudden   savings..
air circulation, for example, between a person
                                                    CONVECTION AND RADIATION
and a cold ceiling or wall) or forced (ventila-
tion).                                              In practice, both phenomena combine.
Traditional air conditioning systems are based      The overall installation performance is the
on convection transfer, hence causing the air       result of ceiling radiation (approximately
drafts sensation. This standard A.C requires        80% power in the cooling case) combined
high energy consumption as it requires to           with natural convection and forced con-
heat/cool a huge mass of air and also to set        vection caused by the ventilation system,
it in motion.
                                                    if any..

Hot ceiling: emits more than it receives            Cold ceiling receives more than it emits

                                                                                     KaRo     | 7
RADIATION DIFFUSION, CEILING HEIGHT                   In the case of an extremely high room, the only
                                                      load increase is due to the wall/windows extra
Radiation occurs in all directions. It is reflected   surface.
and absorbed by the walls and by the occu-
pants, by not by the air.. This way, the heating      This is much less than the load increase that
or cooling sensation is identical in a high ceil-     we would have if using traditional A.C. sys-
ing site as in a 2.50 m. high site. Likewise,         tems.
the comfort sensation is comparable irrespec-
tive of the position of the occupants whether
standing or sitting).

8 |   KaRo
                                                                                                     Thermoactive prefabricated concrete slab

                                                The radiant ceiling
                                                HOT CEILING / COLD CEILING
                                                Winter Operation Principle
                                                Thermoactive prefabricated concrete slab = Hot ceiling

                                                  Hot water circulation

Ceiling vs. Floor
Both systems present the very same
advantage of having integrated emitters.

Despite the fact that radiant floors can
achieve correct performances in heating
mode, radiant ceilings offer the following

•	 Radiant ceilings achieve better perform-
   ance in cooling mode. This is partially
   due to rising hot air movements (Natural
   Convection effect) more favorable is the                                                                         heat loss
                                                                                                                    to the outside
   cold source is above.
•	 Hot-cold floors are limited in terms of
   temperature because they are in direct
   contact with the occupants feet: For ex-     Summer Operation Principle
   ample, during summer time, they should       Thermoactive prefabricated concrete slab = Cold ceiling
   be at a surface temperature no greater
   than 18°C (regulations) or 20-21°C
   (comfort). Comparatively, the cold ceil-
   ing surface may decrease easily down           cold water circulation
   to 16°C (with a condensation secu-
   rity), which notably increases power. The
   same idea applies to heating mode.
•	 Ceilings allow for complete surface use,
   while when it comes to floors, furniture
   (beds, etc.) reduces their useful surface.

                                                                                                                 heat gain from outside

                                                                                                                                     KaRo   | 9
KaRo Systems Radiant Ceilings
KaRo Solar company, a French leader in ra-          PRINCIPLE: WATER CIRCULATION
diant ceiling systems and active member of
Promodul (association for the improvement of        The function of the KaRo system is inspired
thermal comfort), has developed and patented        by nature. The water circulates inside piping.
a range of quality products based on French-        and irrigates the building with temperatures
German technology in radiant ceiling.               between 15°C (59°F) and 35°C (95°F). The
                                                    KaRo system refreshes room temperature
Its long-term action contributes to the devel-      by radiation and convection. A wall or ceiling
opment of the natural Air Conditioning concept      temperature of 20°C (68°F) is enough to cool        Sample of KaRo CU metal ceiling
in France.                                          in a natural, silent and draft free way. The con-
                                                    siderable rate of efficiency is obtained by the
The company has great capability in the radi-
                                                    use of water as the cooling fluid, allowing very
ant ceiling market and a “savoir faire” in the
                                                    large energy savings. .
sector of thermoactive element systems, drew
on the experience acquired over many years          .
in the cold-hot ceiling field. Thermoactive ele-
ment systems on KaRo radiant ceilings have          Adjustment is controlled by means of TAUKA
been installed in more than 1500 buildings.         thermostats, especially fitting KaRo ceilings.

The KaRo team, made up of engineers spe-            This adjustment can be connected to a CTM
cialised in Air Conditioning engineering, is able   (building Central Technical Management sys-         Sample of KaRo Metal ceiling
to provide a solution matching different project    tem) (Intelligent Control).
settings, building types, required performance,
and energy sources...
Sample of KaRo ceiling

10 |    KaRo
                                           Thermoactive prefabricated concrete slab

Thermo active prefabricated slab factory

                                                                     KaRo    | 11
Thermoactive prefabricated slab
Concept:                                           et Technique du Bâtiment) with the obtaining       Concrete reinforcement
                                                   an A ATEx (Appréciation Technique d-Expéri-        6mm                               Transverse reinforcement
The thermoactive prefabricated slab is a re-       mentation).
                                                                                                                                         ø8 mm

inforced concrete slab incorporating a tube
circuit that allows for water circulation inside   The thermoactive prefabricated slab is a real
the 6 cm prefabricated slab, so that the room      structural radiator, whose main advantages
comfort temperature is ensured without any         include:                                                    KaRo pipe ø≤17 mm             Steel clamp ø6 mm

need to make use of other elements, such as
                                                                                                       Slab ≤ 10 cm        Thermo active prefabricated
radiators or air conditioners.                       •	 Fast structural work execution.                                    slab ≤ 10 cm

The closed water circuit uses a waterproof           •	 One single step to build the prefabri-
tube (multilayer pipe, provided by our German           cated slab and the heating and cooling                                                             ≤ 10 cm

partner ROTH) that prevents clay formation.             system, which clearly allows time and
This in turn makes it possible to use current           money saving compared to traditional
water without any need to resort to special             solutions.                                                                                            6 cm
water treatments.
                                                     •	 Use the thermal inertia of concrete
The thermoactive prefabricated slab thus al-            buildings and radiant ceiling technol-
lows for the execution of a reversible radiant          ogy together.                              If the building floors have different own-
ceiling, integrating the heating and cooling         •	 The tubes are placed on the lower part     ers and thus need independent tempera-
system as well as energy storage.                       of the slab, near the room ceiling sur-    ture regulation, , it is recommended to
                                                        face on which the system operates.         insulate one floor from another in order
This procedure has been validated by an                                                            to restrict upward cold-heat transmission.
analysis from the CSBT (Centre Scientifique                                                        Floating floors, for example, may ensure
                                                                                                   proper thermal and acoustic insulation.

                                                     Thermoactive prefabricated concrete slab

12 |   KaRo
                                                              Thermoactive prefabricated concrete slab

Prefabricated slab Circuit Setting
Each prefabricated slab contains one or several water circuits. Consequently, zones can be de-
fined depending on the architect’s needs, in addition to providing each of them with a different
temperature control.
Equally, some space in the slab can be saved for piping, air ducting electrical conduits, luminary,
fire sprinklers etc..

Prefabricated slab containing only one circuit         Prefabricated slab containing two circuits

Circuit Connection
Circuits are interconnected and in turn connected to the water distribution circuit.
A valve system allows each zones to be controlled independently and actived them through a
Tube connection to the hydraulic circuit is made through tube connection following a standard

        Independent regulation                   Thermostat
        of each slab

                                                                                             KaRo   | 13
Floor station with 2 pipes system


           1                                       8

Floor station with 3 pipes system

 4                 5                       6

                       2           3

                               9           7

           1                                       8

4 pipes distribution system

 4             4           5           6                   1.   Pump
                           2                               2.   heat exchanger
                                                           3.   cold exchanger
                                   9                       4.   flow meter
                       1               3                   5.   control valves
                                                           6.   control valves
                       1                       7       8   7.   hot water connection
                                                           8.   Independent slabs
                                                           9.   cold water connection

14 |   KaRo
                                        Thermoactive prefabricated concrete slab

KaRo hydraulic station 3 pipes system

KaRo hydraulic station 2 pipes system

                                                                  KaRo    | 15
Benefitting from Concrete Material Advantages
Apart from its recognized structural qualities,      Some Common Calorific Capacities
concrete offers very interesting thermal             Common materials                                    C (J/kg.K)
qualities, particularly its high thermal inertia.    Expanded polystyrene TH35 1470                      1470
Building inertia can be defined by means of          Structural wood                                     960
the capacity to reduce temperature variations,       Terracotta                                          630 - 1800
whether night-day variations (daily inertia)         Concrete                                            2400 - 2610
or through sequential inertia extending over         Stone                                               2520 - 2790
several days. High inertia provides stable
comfort temperature without showing                   3000

considerable variations.                              2500

Such inertia results from the heat-keeping
values of the materials forming part of the
building.                                              500

Concrete slabs have high inertia that may                0

be used for keeping and recovering heat (or                       polystyrene
                                                                  TH35 1470
                                                                                             Terracota   Concrete   Stone

cold), while significantly reducing building
energy consumption.
                                                    Thermal Effusivity
This is why it is advantageous to integrate the
cold-heat system into a concrete slab. (Free        Thermal effusivity E (J/K.m2.s1/2) represents the
Cooling : The fresness of a summer night            material surface capacity to exchange heat with the
is stored in the concrete and redistributed         environment. Effusivity increases in line with con-
during the warmest part of the day, without         ductivity and thermal capacity.
any energy consumption)                             Concrete effusivity is high, providing it with great ca-
MATERIAL THERMAL QUALITIES                          pacity to accumulate and send out heat.

Thermal Conductivity                                 Some common effusivity
                                                     Matériaux courants                                  E (J/m²Ks0.5)
Conductivity σ (W/m2.K) determines material
                                                     Expanded polystyrene TH35 1470                      100
capacity to transmit heat..
                                                     Structural wood                                     350 – 600
Calorific Capacity                                   Terracotta                                          1200 – 1500

Calorific capacity determines how much en-           Concrete                                            2000 - 2500

ergy is necessary for raising by one degree          Stone                                               2520 - 2790

(°C) the temperature of one kg of that mate-
rial. In other words, it determines the energy        3000

accumulation capacity of a certain material.          2500

During summer time, because of their great            1500
calorific capacity, concrete ceilings will keep       1000
                                                                                                                            The advantage of the concrete is to
night coolness during more time than other             500
                                                                                                                            propose a good conjugation between
materials.                                               0
                                                                                                                            capacity (= storage) and high effusivity
                                                                  polystyrene   Structural   Terracota   Concrete   Stone
                                                                  TH35 1470     Wood                                        (= exchange).

16 |    KaRo
                                                                                                      Thermoactive prefabricated concrete slab

                                             Inertia: Free Energy Accumulation
                                             Example: Day/night cycle in summer                   In winter
                                               •	 Night: If the place is ventilated, the          The principle is similar, but in this case the
                                                  slab is cooled because of night cool-           slab is heated during night (when the energy
                                                  ness                                            is cheaper) and it gives the heat back during
                                                                                                  the day.
                                                    Slab temperature in the morning:
                                                    Tmorning ≈ Toutside                           Active Prefabricated slab Advantages
                                               •	 Day: If the place is insulated, the cold slab   This principle applies to all systems with high
                                                  absorbs the heat sent out by occupants          inertia (such as a concrete slab). The ther-
                                                                                                  moactive prefabricated slab offers an ad-
                                               •	 Slab temperature in the afternoon:              ditional advantage. Contrary to more basic
                                                    Tevening ≈ Tambiance                          systems allowing for uncontrolled energy ac-
                                                                                                  cumulation and return, slab activation allows
                                                    ΔT = Tevening – Tmorning
                                                                                                  the water flow to accelerate or slow down
                                               •	 Conclusion: the slab absorbs during one         cold-heat emission, and control the use of the
                                                  day energy equal to:                            energy stored
                                                    E = ΔT × Cslab × Volumeslab

The higher the C value, the more energy
the slab can absorb, resulting in a longer
use of Free Cooling

                                                                                                                                  KaRo     | 17
Profiter des avantages du matériau béton
Design                                              Structure Fitting and Slab Casting
                                                    (Structural Work)
1. Definition of desired thermal perform-
   ance..                                           Under the Installation recommendation plan:
Considering the building characteristics (ex-        1. Receive pre-slabs on site (localization,
ternal contributions depending on geographi-            check)
cal location, wall orientation and insulation, as    2. Place slabs on previously levelled up
well as internal contributions due to occupan-          props
cy, computer systems, lightning systems, etc.)
                                                     3. Place additional structures
and comfort goals, the thermal engineer de-
termines on a place-by-place basis the neces-        4. Execute struts and channels
sary heating and cooling power.                      5. Eventually place thermal bridge breaks
                                                     6. Cast slab
2. Thermoactive prefabricated slab dis-
   tribution study, based on architectural,          7. Once required concrete resistance is
   forming, and structure plans.                        obtained, remove props
                                                    Following the KaRo connection plan
3. Engineer are setting of a recommended
   water distribution plan..                         1.   Place distribution circuits
We have a software allowing to carry out reli-       2.   Install eventual sub-stations
able simulation of the building air conditioned      3.   Interconnect thermoactive pre-slabs
zones.                                               4.   Connect to water network
•	 Outline the areas to be equipped with the         5.   Pressure tests
   system.                                           6.   Execute adjustment circuits
                                                     7.   Treat slab joints
•	 Independently outline controlled sub-are-
   as, allowing for different adjustment for         8.   Finish ceiling (stucco, painting)
   each rooms                                        9.   Fix elements

18 |     KaRo
                                                          Thermoactive prefabricated concrete slab

Site installation of a thermo active prefabricated slab

                                                                                    KaRo    | 19
Multiple Performances
Choosing the thermoactive prefabricated slab solution means benefitting from a wide spectrum
of advantages; using a seamless solution paves the way for combining the advantages of two
complementary components, while avoiding the usual inconvenient encountered while combining
different systems.
As a result of analysing required intermediary slab functions, the thermoactive prefabricated slab
solution fully meets all the requirements related to each and every stage of a building life cycle.
    •	 Project
    •	 Construction
    •	 Use
    •	 Redevelopment
    •	 Pulling down and recycling

Service during Project Phase
Project flexibility and freedom.
Project flexibility and freedom.
Choosing the radiant ceiling instead of radiators and ventilation/convector heaters saves space
and allows more equipment arrangement flexibility for designers.
Apart from a surface free of equipment and circulation, the radiant ceiling allows for greater flex-
ibility concerning space arrangement, furnished area setting, election of floor covering, etc.
It is a modular system allowing for free choice of areas to be equipped with, and the possibility of
them being independently adjusted.

                   2           3           4          5           6         7     8    9

                                                               room width
                                                          = 3 Thermoactive slab

              The valve is closed to split rooms

                             = Go                  = Stop        Example of a three rows room

20 |    KaRo
                                                         Thermoactive prefabricated concrete slab

Avoid False Ceiling
Many architects would like to avoid the use
of false ceilings; even if false ceiling square
meters are now cheaper, full ceiling cover re-
sults in considerable expenses.
There are other solutions for addressing
acoustic problems and incorporating lightning,
resulting in no more need to systematically                                  Water Pump

use false ceilings. At the same time, modern
                                                   Heat pump                                 Electricity
buildings more frequently deploy clever and
                                                         Solar panel           Gas        Wood, pellets
aesthetic solutions for dealing with acoustic
                                                                   Geothermy         Canadian well
                  Thermoactive slab
                                                  Actively Contributing to High Environmental
                                                  Quality management
                                                  The thermoactive pre-slab integrates the High

                                                  Environmental Quality management (French
                                                  HQE label) principles and offers several ad-
                                                  vantages regarding a ventilation/convector
                                                  heater solution.
                                                   Principles of sustainable development             Improvement.

                      False ceiling
                                                    1.      Harmonious relationship between
                                                            buildings and their immediate en-

                                                    2.      Integrated choice of construction                  
                                                            methods and materials
                                                    3.      The avoidance of nuisance by the
                                                            construction site.
Compared to the use of false ceilings, choos-
ing the thermoactive pre-slab saves around
                                                    4.      Minimizing energy use
10% of the height between two slabs, this is,
                                                    5.      Minimizing water use                                  
between 1.5 and 2 meters for R+5 buildings.
                                                    6.      Minimizing waste in operations                        
Free Choice of Energy Heating Type                  7.      Minimizing building maintenance
                                                            and repair
Since it is totally compatible with any sys-        Comfort
tem of hot/cold water production, the ther-         8.      Hydrothermal control measures                            
moactive prefabricated slab provides great          9.      Acoustic control measures                          
freedom in the choice of energy solution.           10.     Visual attractiveness
You will be free to choose the most con-            11.     Measures to control smells
venient solution: boiler, heat pump, use of
renewable energy, etc. This choice is not
                                                    12.     Hygiene and cleanliness of the in-
necessarily definitive. Changing the energy                 door spaces
source neither poses a problem nor requires         13.     Air quality controls                               
any piping network modification.                    14.     Water quality controls

                                                                                                 KaRo          | 21
Performance during Work Phase
Simplification of construction process.                                         Simplifying Management and Reducing                                              Using Quality Products
                                                                                Construction Terms                                                               Under EC regulations, prefabricated
Installing thermoactive prefabricated slabs is
similar to common inactive slab installation,                                   The use of an industrialized solution, guaran-                                   slab manufacturing is subject to regu-
inducing no special difficulty if placing plan is                               teed and integrated, reduces the number of                                       lar internal control, allowing to guar-
followed.                                                                       field work operations, thus reducing coordina-                                   antee product follow-up and product
                                                                                tion time.                                                                       resistance and quality verification.
In addition, our partners follow the “QUAL-
IPREDAL” quality control procedure, executed                                                                                                                     This control is certified by a qualified
                                                                                It leaves out some unnecessary control and
between prefabricated slab manufacturers                                                                                                                         body.
                                                                                verification operations, while enhancing build-
and construction companies. This allows to                                      ing construction process organization.                                           The company is engaged in voluntary
value industrial prefabricated slab technology                                                                                                                   certification management. NF brand
and highlight all of its advantages. It also takes                              Choosing the thermoactive prefabricated slab                                     guarantees that pre-slab characteris-
into account builders’ and project managers’                                    therefore allows for easier and faster work,                                     tics have been verified by an unbiased
expectations in such fields as:                                                 leaving out several stages if compared to a                                      body, while being permanently ob-
                                                                                traditional air conditioning solution or to non-                                 served by manufacturers. Products so
•	 Responsible development                                                      integrated radiant ceiling or radiant floor.                                     certified prove fitness for using slabs in
•	 Safety                                                                       Suppressing these stages also makes it pos-                                      accordance with current standards.
•	 Economic control                                                             sible to avoid work risks, so that it also means
                                                                                saving additional coordination, work manage-
•	 Execution term management                                                    ment, and execution time
•	 Environment preservation
Every year over 10 millions sqm of prefabri-
cated slabs are placed in France in all kinds of
buildings (residential, offices, etc.).

                                                            CONSTRUCTION STEPS

         Old system                        Radian floor                 Radian metal ceiling                Precast radiant slab
                                                                                                                                             Others stage → no

 Bearing wall, concrete structure   Bearing wall, concrete structure   Bearing wall, concrete structure Bearing wall, concrete structure

 Floor shuttering or precast slab   Floor shuttering or precast slab   Floor shuttering or precast slab   Floor shuttering or precast slab

 Slab cast                          Slab cast                          Slab cast                          Slab cast
                                                                                                                                             stage → no


              ••                                 ••                                 ••

 Installing fan coil and water      Floor insulation and piping                      ×                                   ×
                                                                                                                                             Others stage → no

 heater                             installation.
 Installation of false ceiling      Concrete resurfacing slab finish   False ceiling installation                        ×

 Piping installation and            Piping connection                  Piping connection                  Piping connection
 Electrical connection                            ×                                  ×                                   ×

22 |       KaRo
                                                                                                                      Thermoactive prefabricated concrete slab

                                             Performance during Occupation Phase
The drawing indicates power. It should       HEATING AND COOLING PERFORMANCE                Heating performances (winter)
be noticed that the actual power de-
pends on room setting, heat contribution     1. System Power
and loss, as well as air recycling system.   The thermoactive prefabricated slab shows      Heating power (W/m2) : tube spacing =15 cm.

KaRoSolar has developed a set of com-        results well adapted to different contexts.                                          Room temperature (°C)
puter programs that calculates ceiling       An office building usually requires about 70
                                                                                                                           18       19      20      21      22      23       24
power based on these parameters and it       to 100 W/m2 of heating and cooling power.                                30   64.1     58.7    53.4    48.1    42.7    37.4     32.0
can thus adjust the system to meet dif-                                                                               32   74.8     69.4    64.1    58.7    53.4    48.1     42.7
ferent needs.                                This power can be easily achieved through a

                                                                                             water temperature (°C)
                                                                                                                      34   85.4     80.1    74.8    69.4    64.1    58.7     53.4
                                             moderate water flow (20 l/h/m2) and water
                                             temperature ranging between 15 and 18°C                                  36   96.1     90.8    85.4    80.1    74.8    69.4     64.1

                                             in summer and 30 and 35°C in winter.                                     38   106.8    101.5   96.1    90.8    85.4    80.1     74.8

                                             This temperature range prevents condensa-                                40   117.5    112.1   106.8   101.5   96.1    90.8     85.4

                                             tion risks in cooling mode (we provide dew                               42   128.2    122.8   117.5   112.1   106.8   101.5    96.1
                                             point sensors anyway for security).
                                                                                            Usual conditions
                                             Emission power is roughly proportional to      Heating power (W/m2) : tube spacing = 20 cm.
                                             the temperature difference between the                                               Room temperature (°C)
                                             water and the room.
                                                                                                                           18       19      20      21      22      23      24
                                             By choosing water temperature, we can ad-                                30   56.9     52.2    47.4    42.7    37.9    33.2    28.4
                                             just the power. This is why (with a 15 cm.                               32   66.4     61.6    56.9    52.2    47.4    42.7    37.9
                                             tube plan) in order to obtain 75 W/m2 of
                                                                                            water temperature (°C)

                                                                                                                      34   75.9     71.1    66.4    61.6    56.9    52.2    47.4
                                             power in a place at 27°C, we will use water
                                             at 17°C (this means a 10°C difference).                                  36   85.3     80.6    75.9    71.1    66.4    61.6    56.9

                                                                                                                      38   94.8     90.1    85.3    80.6    75.9    71.1    66.4
                                             Water circulation is then adjusted by the
                                             thermostat and interrupted once the re-                                  40   104.3    99.6    94.8    90.1    85.3    80.6    75.9

                                             quired temperature is achieved.                                          42   113.8    109.0   104.3   99.6    94.8    90.1    85.3

                                                                                            Usual conditions
                                             Ceiling thermal emissions have been de-
                                             termined through certified tests (Stand-       Heating power (W/m2) : tube spacing = 25 cm.
                                             ard EN1264-2) and calculation (Standard                                              Room temperature (°C)
                                             1264-5), for several inter-tube spacing .
                                                                                                                           18       19      20      21      22      23       24
                                             They have been performed at the University
                                             of Stuttgart in March 2010.                                              30   52       47.7    43.3    39.0    34.7    30.3     26.0

                                                                                                                      32   60.7     56.3    52.0    47.7    43.3    39.0     34.7
                                                                                             water temperature (°C)

                                                                                                                      34   69.3     65.0    60.7    56.3    52.0    47.7     43.3

                                                                                                                      36   78       73.7    69.3    65.0    60.7    56.3     52.0

                                                                                                                      38   86.7     82.3    78.0    73.7    69.3    65.0     60.7

                                                                                                                      40   95.3     91.0    86.7    82.3    78.0    73.7     69.3

                                                                                                                      42   104.0    99.7    95.3    91.0    86.7    82.3     78.0

                                                                                            Conditions usuelles

                                                                                                                                                              KaRo          | 23
2. Power Increase by Convection                  Cooling performances (Summer)
Power takes into account the natural and
forced convection phenomenon.                    Cooling power (W/m2) : tube spacing = 15 cm.
                                                                                                                                             Rasing air ow follows the ceiling surface
Forced convection with air recycling, is more                                         Room temperature (°C)                                         and takes his temperature.

efficient with an ideally designed air diffus-                                 24       25     26     27     28      29      30
er. This allows benefitting from the Coanda                               14   75.0     82.5   90.0   97.4   104.9   112.4   119.9
effect, a physical phenomenon that can be
                                                                          15   67.5     75.0   82.5   90.0   97.4    104.9   112.4
described as follows:
                                                 water temperature (°C)

                                                                          16   60.0     67.5   75.0   82.5   90.0    97.4    104.9
                                                                                                                                     Coandä rule: Blowing air follow the ceiling surface.
A fluid flow (like an air current) circulating                            17   52.5     60.0   67.5   75.0   82.5    90.0    97.4
near a surface has a tendency to follow this
                                                                          18   45.0     52.5   60.0   67.5   75.0    82.5    90.0
                                                                          19   37.5     45.0   52.5   60.0   67.5    75.0    82.5
Exploiting this phenomenon with a rasing air
                                                                          20   30.0     37.5   45.0   52.5   60.0    67.5    75.0
flow allows to improve the ceiling efficacy
and thus to achieve the desired power while      Usual conditions
reducing energy consumption.
                                                 Cooling power (W/m2) : tube spacing = 20 cm.
3. Adjustment
                                                                                      Room temperature (°C)
The water temperature gives the maximum                                        24       25     26     27     28      29      30
system heating and cooling power.
                                                                          14   64.8     71.3   77.8   84.2   90.7    97.2    103.7

Each zone is independently monitored                                      15   58.3     64.8   71.3   77.8   84.2    90.7    97.2
through a thermostat that controls the
                                                 water temperature (°C)

                                                                          16   51.8     58.3   64.8   71.3   77.8    84.2    90.7
valve pertaining to the zone circuit (open or
                                                                          17   45.4     51.8   58.3   64.8   71.3    77.8    84.2
closed position). Valve alternate opening and
closing combined with ceiling inertia allow                               18   38.9     45.4   51.8   58.3   64.8    71.3    77.8

getting a steady temperature.                                             19   32.4     38.9   45.4   51.8   58.3    64.8    71.3

With an eye on better use of slab inertia, an                             20   25.9     32.4   38.9   45.4   51.8    58.3    64.8

adjustment can be scheduled (eventually          Usual conditions
through a CTM) with power requests set
some hours before the occupancy period
                                                 Cooling power (W/m2) : tube spacing = 25 cm.
(as in the case of an office for example). The
thermostat turns the relay on for keeping                                             Room temperature (°C)
the temperature steady during the day if                                       24       25     26     27     28      29      30
necessary.                                                                14   57.9     63.7   69.5   75.3   81.0    86.8    92.6

In general, slab inertia is sufficient for                                15   52.1     57.9   63.7   69.5   75.3    81.0    86.8
                                                 water temperature (°C)

activation to occur during the night.                                     16   46.3     52.1   57.9   63.7   69.5    75.3    81.0

                                                                          17   40.5     46.3   52.1   57.9   63.7    69.5    75.3

                                                                          18   34.7     40.5   46.3   52.1   57.9    63.7    69.5

                                                                          19   28.9     34.7   40.5   46.3   52.1    57.9    63.7

                                                                          20   23.2     28.9   34.7   40.5   46.3    52.1    57.9

                                                 Usual conditions

24 |   KaRo
                                                                                 Thermoactive prefabricated concrete slab

Heating and cooling performances
 The two diagram charts give fast and accurate information to select a precast radiant slab. The actual capacity of the
 slab depends of the room configuration, outside radiation, inside heating load, ventilation, etc.
 KaRo Solar has developed a software which calculates the heating and cooling capacity considering all the parameters.

                                                      Cooling power



emission power (W/m2)







                              5    6    7    8         9             10          11              12    13    14      15
                                                 Temperature difference - ΔT=Troom - Twater

                                                 Heating power


emission power (W/m2)






                           10     11   12   13       14            15           16            17      18    19      20
                                                    Temperature difference - ΔT=Twater - Troom

                                                                                                            KaRo   | 25
3.1 Heating performance on 24 hours cycle (winter in Paris inside temperature set at 20°C)
The first diagram shows temperature (external and internal) vs. time, as well as different slab
activation periods. Heating begins a bit earlier on Monday after a long weekend stop at 9 AM
heating stop for all the day as room temperature remain constant between 19°C and 20°C
using energy stored inside the slab.
                                        Precast radiant slab situation: of ce Nord Paris water temperature in = 35°C
                                              Evolution of températures (°C) /Heating capacity needed (W/m2)


 30                                                                                                                                              180
 26                                                                                                                                              160
 22                                                                                                                                              140
 18                                                                                                                                              120
 14                                                                                                                                              100
 10                                                                                                                                              80
  6                                                                                                                                              60
  2                                                                                                            Of ce temp (°C)                   40
  0                                                                                                            Temp. ceiling (°C)
                                                                                                               Heating capacity needed (W/m2)
  2                                                                                                                                              20
                                                                                                               Outside temp. (°C)
 -6                                                                                                                                               -6
      0:00 h.                                       8:00 h.                                   16:00 h.                                           24:00 h.

3.2 Efficiency on 7 days cycle (summer in Paris inside set point 26°C)
The drawing shows temperature (external and internal) vs. time, as well as different slab
activation periods. Activation begins a bit earlier on Monday to make up for longer weekend
system stop.
                                     Precast radiant slab situation: of ce Nord Paris water temperature in = 16 °C

                                           Evolution of temperatures (°C) /Heating capacity needed (W/m2)

36                                                                                                                                               180
                   Temp. ceiling (°C)
34                 Of ce temp (°C)
32                 Heating capacity needed (W/m2)                                                                                                160
                   Outside temp. (°C)
28                                                                                                                                               140
24                                                                                                                                               120
20                                                                                                                                               100
16                                                                                                                                               80
12                                                                                                                                               60
 8                                                                                                                                               40
 4                                                                                                                                               20
 0                                                                                                                                            0
 11- aout           12- août           13- août               14- août      15- août          16- août            17- août            18- août
 Heating capacity needed: 7h Monday; 6h tuesday & Thursday; 3h Wednesday; 5h Friday

These simulations as been done by Tribu Engineering.

26 |        KaRo
                                                Thermoactive prefabricated concrete slab

4. Auto Adjustment.                                            18 °C

Natural system reactivity is also a warrant
of comfort. The cold ceiling principle allows
adjusting to heat variations generated           25°C                      25°C
within the place.
In other words, if 10 people enter a room at
the same time, the thermoactive slab heat
absorption will automatically increase and                     18 °C

it will decrease as well once the people
leave the place.

Therefore, we do not need to turn the            25°C                      25°C

air conditioner on and off when going to
another place: the thermoactive ceiling will
detect your presence.

Bundestag Berlin, equipé de plafonds Karo

                                                                          KaRo    | 27
TO HAVE A GREAT COMFORT                           The thermoactive prefabricated slab can
                                                  prevent these problems. The only air cir-
Cooling by radiation does not imply any air
                                                  culation necessary is the hygienic re-
circulation, except for necessary hygienic
air renewals. There is therefore no air draft,
which results into a feeling of greater com-      This slight ventilation contributes to en-
fort.                                             hance ceiling performance (convection),
                                                  while being afresh and pleasant air.
Unlike traditional air conditioning systems,
which have to send out cold air, generating       In 1999, 2,000 Legionella cases (Legion-
a considerable current, and consequently          naire’s disease) were reported in France,
resulting in a feeling of lack of comfort,        most of them due to improper air condi-
throat problems, etc., the thermoactive pre-      tioning system operation. The use of cold
fabricated slab ensures a gentle and peace-       ceiling is a way to avoid this risk
ful environment.
                                                  Guaranteeing Proper Acoustic Performance
Radiant ceiling systems have been largely
developed for luxurious buildings where           Radiant ceiling systems are noiseless and
comfort was essential. Now, this system is        offer greater acoustic comfort if com-
accessible to all types of projects.              pared to traditional systems.

Improving Air Quality                             False ceilings also offer the advantage of
                                                  providing acoustic isolation between.
Fresh air circulation is commonly a
source of health problems due to humid            In this regard, ceiling integration into
air (favoring bacteria proliferation – Le-        concrete slab is a priori a flaw, compared
gionella - and moisture near to air con-          to suspended ceilings.
                                                  Where high acoustic insulation is neces-
This is due to improper air renewal or just       sary, acoustic panel systems have to be
caused by an excessively cold air current or      used, replacing fake ceilings.
an air draft sensation (throat problems, etc.).
                                                                                               In this case, we can use, for example,
                                                                                               partial suspended acoustic elements.
                                                                                               These elements exert a very low influ-
                                                                                               ence on thermal performance, but re-
                                                                                               duce to a considerable extent internal
                                                                                               noise. Partial ceiling cover provides the
                                                                                               very same acoustic characteristics as
                                                                                               total cover without blocking heat emis-

28 |   KaRo
                                                               Thermoactive prefabricated concrete slab

Precast radian slab with acoustic ceiling covering 50% of the area.

Precast radian slab with acoustic baffles

                                                                                         KaRo    | 29
No risk of condensation                             This reliability is ensured. KaRo systems
                                                    have been used for decades on several ceil-
Surface condensation risks are avoided
                                                    ings with ultra thin tubes (capillary mats)
through the systematically use of a dew
                                                    without any obstruction observed.
point sensor.
                                                    Only external elements allowing for water
This probe is connected to the thermostat,
                                                    circulation (pumps, valves, etc.) will require
and ensures that the water entering the cir-
                                                    maintenance. The system will operate as it
cuit is always at least 2ºC above dew point
                                                    did during the first operation day all over the
                                                    building life.
This mechanism prevents condensation,
while providing sufficiently low ceiling tem-
perature. Air dehumidifying is a possible op-       In case of Perforations
tion, albeit unnecessary under our latitudes.
                                                    Perforations and fixations can eventually be
Ensured Reliability                                 carried out on finished ceilings after structures
                                                    and piping are located (using a metallic struc-
The tube used for installation is Roth’s X-         ture detector or thermal camera).
PERT S5+® PERT, a state-of-the-art prod-
uct made up of 5 extruded overlapping lay-          Fixation drilling should not make concrete
ers.                                                explode. Shot anchoring or fixation systems
                                                    should be subject to technical control author-
This is a solid and perfectly insulated mate-       izing their use on slab surface (penetration
rial, avoiding tube tearing, air infiltration and   limiter).
                                                    Note that in case of accidental perforation of
Water flows through a closed circuit, with-         the pipes, the damaged area can be isolated
out external air exchange; hence it remains         (by closing the valves) and a reparation can be
clean over many years, without neither clay         performed in approx. 2 hours. (by a plumber).
formation nor obstruction risks.

30 |    KaRo
                                                            Thermoactive prefabricated concrete slab

Performances during Restructuration Phase
An office space is usually reconditioned. The
thermoactive prefabricated slab is adapted              2           3            4         5            6           7       8      9

to these changes. Active ceiling area modu-
lation allows to easily change a room size                                                   Room width
                                                                                         =2 Thermoactive slab

by changing circuit connection at distributor      The valve is closed to split rooms
Changes are, however, restricted by the
prefabricated slab size. Although it is easy                   = Go                     = Stop                  Exemple of a twoo rows room
to connect or disconnect two independent
circuits, it is impossible to divide one circuit
into two.                                               2           3            4         5            6           7       8       9

This inconveniency should be taken into ac-                                                         room width
count in initial plans and eventually solved                                                   = 3 Thermoactive slab

by putting two circuits within one single pre-     The valve is closed to split rooms

fabricated slab..

                                                                  = Go                  = Stop         Example of a three rows room

Performance during Pulling Down Phase
PRESERVING THE ENVIRONMENT.                        cated slab solution regarding building users’
                                                   comfort and health:
In the light of the cold-heat system concept
simplicity and because of the limited quan-        Carbon balance is equal to 20 kg of CO2 per
tity and non-toxicity of the components used       prefabricated slab sqm for 100 year life. This
for execution (simple tubes), pulling down         can be compared to 1 kg of refrigerating gas
has less environmental impact than tradi-          like CFC (used in traditional systems) repre-
tional solutions such as convectors, radia-        senting between 1,500 and 3,000 kg of CO2.
tors, or air conditioning systems.
Based on the life cycle analysis method
(LCA), the prefabricated slab environmental
and health statement card (FDES – “Fiches
de Déclarations Environnementales et Sani-
taires” in France) provides builders and work
managers with useful information about en-
vironmental impact resulting from product
manufacturing, execution, life, and life end.
This is another advantage of the prefabri-

                                                                                                                        KaRo       | 31
Performance during Pulling Down Phase
COMPARATIVE COSTS                                                                                                                                                                               •	 Put water in circulation in comparison
                                                                                                                                                                                                   with air circulation
Reduction of construction costs.
Cold ceiling systems are at first more expensive                                                                                                                                                And it also saves energy resulting from
when it comes to their construction if compared to                                                                                                                                              concrete inertia (depending on the building
traditional air conditioners and radiators.                                                                                                                                                     thermal insulation) and free cooling.
The thermoactive prefabricated slab with the in-                                                                                                                                                The thermoactive pre-slab is then the solution
tegrated system induce a cheaper construction,                                                                                                                                                  using the least energy. This is an important
whilst still allowing to make a profit from invest-                                                                                                                                             point to bear in mind in today budget, and
ment through its operation saving. Comfort and                                                                                                                                                  even more in future budget
energy saving are thus more accessible.                                                                                                                                                         Reduction in Maintenance Costs
                                                                                                                                                                                                The tubes incorporated into the concrete are
                                                                                                                                                                                                protected against any kind of degradation.
 200                                                                                                                                                                                                                         90
 150                                                                                                                                                                                                                         60
                                                                                                                                                                                                yearly operating cost (k€)

                                                                                                                                                                                                                                                     Fan-coil units

                                                                                                                                                                                                                             40               71
                                                                                                                                                              ThermoActive Prefabricated Slab

 100                                                                                                                                                                                                                         20                                       187
                                                                                                  Under oor heating/cooling

                                                                                                                              Ceiling heating/cooling

                                                          VAV Air conditioning

                                   Fan-coil units

                                                                                                                                                                                                                                  Operating        Maintenance

                                                                                                                                                                                                Only pumps and water heating/cooling sys-
                                VMC                                                               Heater- fan-coil units
                                                                                                                                                                                                tems require maintenance.
                                Energy production                                                 Ceiling/ oor
                                Regulation                                                        Slab activation                                                                               This results in low maintenance expenses.
                                                                                                                                                                                                Globally, final operation costs are less than
Radiant ceilings use less energy than traditional                                                                                                                                               50% compared to traditional installation.
systems.                                                                                                                                                                                        Performance remains constant without
                                                                                                                                                                                                maintenance or control related to compo-
•	 Save energy necessary for fluid cooling                                                                                                                                                                                                                                             ENERGY SAVINGS
                                                                                                                                                                                                nent duration.
                          600                                                                                                                                                                   The system will operate as it did during                                                     -35%
yearly comsuption (MWH)

                          500                       348                                                                                                                                         the first day all over the building life cycle                                         vs conventional systems
                                                                                 Fan-coil units

                          300                                                                                                 248
                          200                       318

                          100                                                                                                 187

                                  Winter              Summer

32 |                            KaRo
                                                                                                                         Thermoactive prefabricated concrete slab

                                                                    Service and Support
                                                                    •	 Technical advice                              •	 Planning of delivery with daily follow-up,
                                                                    •	 Search for the solution that best fits each        guarantee of agreed term
                                                                       project needs                                 Set up

                                                                    •	 Technical support all over operation time     •	 Drawing of the prefabricated slab place-
                                                                                                                        ment plan
                                                                                                                     •	 Drawing of the hydraulic connection plan
                                                                    •	 Computer management of information
                                                                       flow (drawings in dwg format; dxf CAD)        The choice of thermoactive prefabricated slab
                                                                    •	 Efficient and recognized calculation soft-    means knowing how to anticipate, control,
                                                                       ware for slab sizing                          ensure.,
                                                                    •	 Thermal simulation for calculating radiant    •	 Anticipate preparation
                                                                        ceiling power                                •	 Control the work management
                                                                                                                     •	 Ensure a good finishing
                                                                    •	 Logistic service concerning the work.
                                                                       Setting up an initial schedule

                        100% Peak Power

                37.5%     Fan & Motor
                                                       Pumps 1.5%
                18.8%     Load from lights                  7.5%
Chiller 62.5%

                9.3%                                        9.4%
                          Air Transport load                1.9%

                34.4%     Other loads                       34.4%

                    CONVENTIONAL               RADIANT COOLING
                    HVAC SYSTEM                   HVAC SYSTEM

                                                                                                                                                    KaRo    | 33
KaRo Solar
13 Chemin du Levant
F-01210 - Ferney Voltaire
Tél. +33 (0)4 50 40 91 83
Fax +33 (0)4 50 40 08 57

To top