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148 LOWEX GUIDEBOOK
Building typeHeating generationHeating emissionCooling generationCooling emissionStorage
CASE STUDIES - NESTLE FRANCE HEAD OFFICE
NOISIEL, MARNE-LA-VALLÉE, FRANCE
residential, , , , , office,office,office,office,office, school, other
boilerboilerboilerboilerboiler,,,,, central heat pump, DH, solar, cogeneration, otherradiators/convectors, floor, , , , , wall, ceiling, airceiling, airceiling, airceiling, airceiling, airheat pump, DC, otherotherotherotherotherradiators/convectors, floor, wall, ceiling,ceiling,ceiling,ceiling,ceiling, airstorage tank, aquifer, other
Nestlé France, French sister
company of the famous Swiss firm
decided to establish its Head
Office in an old chocolate factory
(Meunier chocolate) some buildings
of which are registered as Cultural
and historical heritage by the
French authorities. Most of the
retrofitted buildings are equipped
with heating and cooling ceilings.
This system was chosen because
of the silent running. This site was
one of the very first where this type
of system has been installed in
France, and it’s on the largest
scale. It was to preserve the
heritage value that it was decided
to keep the external aspect of
buildings and to install advanced
equipment inside.
GENERAL DATAPrincipal: Nestlé FranceArchitects: Reichen and RobertConstructor: Clestra (Clina; Karo)Installer: Sulzer-Infra (Laurent Brouillet,
Martet-Mercier,Payet-Pluchet)Energy concept:Hand-over: 1994
FRA 2FRA 2FRA 2FRA 2FRA 2
PROJECT DESCRIPTION
BUILDING DATABuilding Envelope:Outside walls of the retrofit ted have beeninsulated. Each window (doubleglazed)is equipped with external shading device,automatically operated according tosolar radiation.Air tightness: not measuredVolume: more than 100 000 m3
Surface area: 34 000 m2
Specific heat load:LNG Boilers: 9 200 kWSpecific cooling load:
6 000 kW
149EXAMPLES OF LOWEX BUILDINGS
GENERAL DESCRIPTIONCeiling is used both for heating and
cooling. For heating it’s only a part of thesystem; the other is done by air heating.Panels are connected to a water loop fromthe heat exchanger to rooms. The AHU areequipped with heat recovery coils whichenable to reduce heat losses due to theventilation. Controls in rooms enable toadjust heat supply to the actual demand.
The network of thin diameter polypropyl-ene pipes (2 mm) is laid out in metallicpanels inside which warmed or cooledwater circulates. The power delivered bythis kind of system is about 45 W/m² for atemperature trop of 3 °C (33/30 °C). Panelsare connected with each other by anindividual loop of polypropylene pipes :16/20 mm. Each loop supplies only oneroom with a maximum of 15 panels.Controlled temperatures:
Winter: 20 °CSummer: 24 °C
Input temperatures in the emissionsystem:
Cooling: 15.5 °C (return: 18.5 °C)Heating: 33 °C (return: 30 °C)
OVERVIEWHeat generation:
Gas boilers with heatrecovery by condensation.
Cooling generation:Cooling water production andcooling towers (the towers allow afree-cooling)
Emission system:Heating and cooling ceiling withcapillary tubes inside metallicpanels.
Costs of emission system:About 250 euro/m²
Ventilation:Double-flux: heat recovery topre-heat the new air incoming.Anti-condensation safety control
INSTALLATION SCHEME
Figure FRA 2.1. Scheme of distributionsystem of cold and hot water to ceilingloops.
DESCRIPTION OF INSTALLATIONS
150 LOWEX GUIDEBOOK
Figure FRA 2.2.Technical “hydro”cupboards.
Figure FRA 2.3. Detail of a room ceilingloop: each loop can supply 3 rows ofpanels. 4 toothing points are kept inorder to allow a new configuration ofoffices.
Figure FRA 2.4. “Higher” and lowtemperatures circuits are set in series inorder to favour “cold returns” togeneration.
Figure FRA 2.5 a and b. System principle of air handling units.
151EXAMPLES OF LOWEX BUILDINGS
Figure FRA 2.6. Polypropylène capillarytubes in a panel
MEASUREMENTSMany meters are installed in the technical
room (heat and energy, electricity).4 temperatures are also measured each6 minutes.The hydraulic installation is also equippedwith several (water meters and tempera-tures).
The air treatment installation is equippedwith different meters (running time ofexhaust ventilators, of electrical heaters.
2 offices are equipped:- air temperature at 0.40 m,- air temperature at 1.20 m,- air temperature at 1.50 m,- air temperature at 2.00 m,- operative temperature at 1.50 m,- relative humidity at 1.50 m,- incoming air temperature,- ceiling surface temperature- exhaust air temperatureExternal conditions are also measured:
temperature, relative humidity, globalhorizontal solar radiation
HEATING-UP AND COOLING-OFFHeating
Ceilings are supplied by hot water at33 °C. For a temperature drop of 3 °C,thermal power reaches 45 W/m2.
In some rooms, the heating is providedby local emitters or heating floors.Cooling
Radiating ceilings bring some con-straints:
- cooling power is limited 70 W/m2 withthe type used,
- to prevent condensation, the tempera-ture has to be kept above the dew-point.
AIR TREATMENT AND CONTROLSTRATEGY
The ventilation is a double-flux. It’s adisplacement ventilation: air incomes bythe floor close to facades (very low speedentrances), it’s exhausted on the upper partof opposite partitions.
Air treatment units are equipped withheat recovery coils to pre-heat the new airincoming in winter.
Air treatment system operates with allnew air; a total cycling can be set duringun-occupation to maintain a certain level inrooms and during the early morning boostperiod.- control of room temperature:Water flow circulating in panels loops iscontrolled by an on-off slow action valveoperated by a room air thermostat set onthe wall of each room,- control of new air:Temperature of air blown in rooms iscontrolled by a sensor set in the airhandling unit,- anti-condensation safety control:A humidity sensor, set in the walls of therooms, disables cooling supply when thepanels surface temperatures come close toroom air dew point.
ENERGY USE (FOR A YEAR)A survey has been carried out during two
years with two main objectives:- to measure actual energy consumptionsof a cooling system by refreshing ceilings,- to know ambient conditions obtainedinside the rooms.
The energy consumptions measured areat an average level of common values forinstalltions equipped by ventilating convec-tors.Heat consumption: 114 kWh/year.m 2
Thermal useful cold consumption:62 kWh/year.m2
Electricity consumption:90 kWh/year.m2
Global COP for summer:2.00
COMFORTThe displacement ventilation creates
around occupants a “lake” of new airpermanently renewed.
EXPERIENCES – MEASUREMENTS
152 LOWEX GUIDEBOOK
OCCUPANTSWhen considering the different ways for
renovating all the buildings of the site, it has
Figure FRA 2.9.Operative temperatures in two offices (east and west) – 2 nd winter.
Figure FRA 2.8. Operative temperatures in two offices (east and west) – Summer.
Figure FRA 2.7. Operative temperatures in two offices (east and west) – Mid-season.
EXPERIENCES - USERS
LITERATURE
been decided to install a very new technol-ogy for France: chilled ceiling air condition-ing system associated with displacementventilation.
The major reason of that choice was theexpected low energy consumption, thesilent running and the savings of room andfloor surfaces.
Feldmann, C. (CoSTIC), Young, D.T.(OTH Bâtiments) 1995. La climatisation parplafonds rayonnants : l’exemple du siègesocial de Nestlé Frace, Promoclim, N°5,september 1995, pp. 16-25.
Publication within reports of the IEAAnnex 28, 1996. “Low Energy Cooling.”
Evaluation des performances d’unsystème de climatisation par plafondrafraîchissant : Nestlé France à Noisiel.