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LOW TEMPERATURE HEATING SYSTEMSINCREASED ENERGY EFFICIENCY AND IMPROVED COMFORT
LOW TEMPERATURE HEATING SYSTEMS
INCREASED ENERGY EFFICIENCY AND IMPROVED COMFORT
WHAT IS A LOW
TEMPERATURE HEATING
SYSTEM?
In a low temperature system the distributingtemperature of the water or air in the systemis close to room temperature where as in thetraditional radiator distribution system, thetemperature of the circulating water isbetween +50–+80°C. If the heat distributionis managed using a low temperature under-floor heating system the temperature of thewater is only about +25–+35°C. When theheat is distributed through the whole floorarea, the temperature of the water can bemuch lower than that required in normalradiators.
The heat carrier in a normal cooling systemis cooled to approximately +10°C. In a lowtemperature system this temperature canremain as high as +20°C, which is close tothe desired room temperature.
Low temperature systems successfullycombine both traditional and innovative newapproaches to heating. Usually the heat istransferred into the room through air or liquidcirculation systems and the same systemcan often be used for both heating andcooling.
Low temperature heating systems
or high temperature cooling
systems that are suitable for
office buildings, service buildings
and residential buildings, can use
a variety of fuels and renewable
energy sources. These systems
use energy efficiently while
providing a comfortable indoor
climate.
A SUSTAINABLE AND
FLEXIBLE APPROACH
TO HEATING
It is widely accepted that buildings of thefuture will need to be built in a more sustain-able and environmentally friendly way. Lowtemperature heating and cooling systemsrepresent a sustainable choice as they areenergy efficient, can utilise renewable energysources and provide a comfortable andhealthy indoor climate.
Low temperature heating systems aresustainable because they are flexible. Thesesystems are not bound to any one energysource and fuel switching does not entailexcessive cost. Low temperature systemscan utilise a variety of sources of heatincluding district heat, biofuel, solar energy,gas, oil or electricity, and so the user is notconstrained by choices made in the planningphase.
A HEALTHY COMFORTABLE
AND SAFE L IVING
ENVIRONMENT
Research shows that people living in houseswith low temperature heating systems arevery satisfied with ambient indoor air quality.In particular, thermal comfort levels areconsidered to be higher than in houses with a
traditional heating system. Residents alsoexperienced a reduction in draughts anddust, and reported fresher air in houses withlow temperature heating systems.
Under floor heating systems distributeheat more equally, and offer higher comfortlevels than systems which transfer heatthrough air. By using low temperatureheating systems the room temperature canbe decreased by a few degrees, which ismore energy efficient and healthier foroccupants. Low temperature heatingsystems do not require radiators, which canbe unsightly and hard to clean. This offersthe additional advantages of increased livingspace and more flexibility in terms of interiordesign. The absence of radiators alsoprovides a safer environment for childrenduring the heating season.
IEA Research Project on low
temperature heating systems,
Annex 37. Eleven countries
participate.
ECONOMICALLY
EFFICIENT HEATING
SYSTEMS
Thorough planning and expert implementa-tion are prerequisites for an appropriate andfunctional system. System flexibility will bedependent on the choice of appliances andoverall system design, which can be difficultand expensive to change after installation.
The life cycle costs of a low temperatureheating system are about the same as of atraditional system. Although the initialinvestment might be slightly higher thesystem offers increased flexibility in terms offuel choice and increased energy efficiency,for example the efficiency in solar heating isconsiderably higher in a low temperatureheating system than in a traditional one.
ThermoNet®-uimahallijärjestelmä onintegroitu kokonaisuus, jossa on huomioituallastilojen, puku- ja pesuhuoneiden sekämuiden tilojen erityisvaatimukset. Joustavamatalalämpötilajärjestelmä optimoi elinkaa-rikustannukset sekä minimoi lämmityksestäja jäähdytyksestä aiheutuvat ympäristövaiku-tukset. Tehtaalta mahdollisimman valmiiksikoottuina modulaarisina komponentteinatoimitettava järjestelmä myös nopeuttaarakennus- tai saneerausaikataulua.
AaltoAlvarissa toteutettiin laaja uudistus- japerusparannusohjelma vuosina 1998-2000.Lähes 65 000 kuution kokoisen liikuntake-skuksen tiloihin asennettiin muun muassaThermoNet®-matalalämpötilajärjestelmä.Peruskorjauksen jälkeen esimerkiksi al-lasveden lämmitysjärjestelmän paluuvesihyödynnetään ilmastoinnin lämmitykseen.Lämmitysenergian kulutus on laskenut reilunviidenneksen samalla kun sisäolosuhteet ovatparantuneet merkittävästi.
Uimahallien ja kylpylöiden vaativista japoikkeavista olosuhteista johtuen niissäkulutetaan muihin rakennuksiin verrattunarunsaasti lämpö- ja sähköenergiaa sekä vettä.Merkittävä osa energiankulutuksestaaiheutuu allasveden haihtumisesta. Talotekni-ikkajärjestelmän keskeisin tehtävä onkinhallita suurta kosteuskuormaa.
LYCÉE LÉONARD DE VINCI – CALAIS, FRANCE
This case study involved the application of awide variety of environmentally soundmeasures to the building of a school. Thesemeasures included selection of reusable orlocal building materials and double-fluxventilation (heat recovery on air exchange).Solar collectors with a heat pump are usedfor water heating for the kitchens and 75 m2
of PV cells were fitted to generate electricityfor security lighting and alarms. A combina-tion of construction techniques, technicaldevices and energy efficient architecturehave realised a 30% energy saving.
The gas-fueled combined heat and powergeneration system produces heat for theheating system and electricity for other uses.Electricity is also produced using a windgenerator which was installed at the begin-ning of the construction phase. Even when
electricity supply and demand are notsimultaneous, a balance is achieved on anannual basis. Electricity produced during thesummer months when the school is closedis sold back to the national grid.
Use of natural daylight has been optimisedin class rooms and corridors and althoughsome overheating occurred in May and Juneduring the first year window blinds wereinstalled and the problem has been solved.
Contact information:Lycée Léonard de VinciMr. Gérard BonnelTel: +33 3 2119 0721Fax: +33 3 2119 [email protected]
The lycée Léonard de Vinci-Calais,
France is a demonstration project
for the French High Environmen-
tal Quality (HEQ) approach.
CENTRE FOR SUSTAINABLE BUILDING – KASSEL, GERMANY
The low energy office of the
Centre for Sustainable Building is
a project demonstrating the
implementation of a new low
temperature hydronic heating
and cooling system.
Contact information:Centre for Sustainable Building (ZUB)Mr. Jürgen LaudenbachTel: +49 561 804 3189Fax: +49 561 804 [email protected]
Pipes are embedded in the concrete slabsand floor construction. A ground heatexchanger (pipes in the basement slab)facilitates utilisation of the coolness of theunderlying ground, thus using a renewableenergy source.The ZUB office building is an example of hownew low temperature heating/coolingsystems and new environmentally friendlybuilding materials can be used. This casestudy illustrates the practical implementationof these approaches to building projects.
The new three storey building (net floorarea 1732 m2) is attached to an existingpreserved building and consists of threedifferent areas; an exhibition space; a venuefor events; offices and a separate area forexperimental research into innovativebuilding technologies and services.
To achieve a very low energy demand(calculated annual heating demand is16.5 kWh/m2), special measures have beenadopted. The U-value of the exterior walls is0.11 W/m2K. Triple glazed windows with aU-value of 0.6 W/m2K, have been chosen forthe mainly south facing large window area,
minimising heat loss and maximising solargain.
The minimal frame-fraction of the woodenfacade construction helps to reduce heatlosses. Careful planning of all joints hasminimised thermal bridging.
To save electricity, use of natural lightinghas been optimised and ventilation strategieshave been implemented.
A good level of comfort has been reportedby occupants. This was a high priority for thebuilding owner.
An important aspect of the overall conceptis the use of sustainable building materials. Aclay wall, made from unbaked clay bricks,stands in the centre of the building. Thiswall, has great heat retention capacity and bydampening fluctuations in humidity, works asa climate wall.
To monitor the aims of this project andverify its achievements, an intensiveresearch programme “Solar OptimisedBuilding” funded by the German Ministryof Economic and Technology is currentlybeing run.
Photo: © C. Meyer
CARISVEN – HEERLEN, THE NETHERLANDS
IDIC RESEARCH CENTRE – IWATE, JAPAN
Chilled Radiators for Radiant
Cooling and Dehumidification.
Water temperature operated below dewpoint facilitates the dehumidification of theair. The large surface area of the radiators,mainly designed for cooling of the building,allow the use of heat pumps at high efficien-cy with water temperatures of 30–40 °Cduring the heating season.
Contact information:PS Company LtdMr. Y. [email protected]
The IDIC Research Centre is situated in theNorth-eastern part of Japan, where wintertemperatures fall well below freezing pointand summer temperatures reach 30°C ormore with high humidity.
This building utilises room radiators forheating and cooling as well as for dehumidifi-cation of the indoor air. In addition, the southfacing glass façade effectively utilisesdeciduous trees, which provide shade insummer and allow solar gain in winter toreduce space cooling and heating require-ments. Continuous operation of radiators atrelatively high temperature for cooling insummer season, and low temperature forheating in winter season provides a lowenergy system and high levels of comfort.Both heating and cooling energy areextracted from groundwater at 12°C.
The Carisven project was developed by CorioVastu bv, Heerlen, in close co-operation withthe municipality of Heerlen. The project hasbeen extensively monitored by Novem (theNetherlands Agency for Energy and theEnvironment) within the framework of theMarket Introduction Programme for LowTemperature Heating Systems. ThisProgramme was conducted by Novem onbehalf of the Dutch Ministries of EconomicalAffairs and Housing, Spatial Planning and theEnvironment.
There are two types of dwellings. The A/B-type has an unheated south facing sunlounge overlooking the garden. The C/D-typehas an unheated south facing sun loungeoverlooking the street. Individual dwellingscan have customised floor plans.
All dwellings have wall heating. A solarcollector preheats the water for centralheating and domestic hot water. A built-in gasboiler is used for additional heating. PV-cellsare used for electricity generation and rainwater is stored in an underground tank forreuse.
All dwellings have a high efficiency solarboiler for space heating as well as fordomestic hot water supply. A solar collectorpreheats the water in the storage tank. Whennecessary, a natural gas boiler heats waterfor domestic hot water supply and use in thecentral heating system.
A wall heating system has been installedwith a maximum design supply temperatureof 50°C and a design return temperature of40°C. The houses are ventilated naturally.
A survey amongst occupants showed avery high level of satisfaction with thermalcomfort and indoor air quality. Occupantsindicated that they were very pleased withthe Low Temperature Heating System andthat they would recommend it to others.
Contact Information:Novem (Netherlands Agency forEnergy and the Environment)Mr. Paul RamsakTel: +31 46 420 [email protected]
“Carisven” is a demonstration
project for the Dutch sustainable
and low-energy building pro-
gramme. It is comprised of 54
semi-detached houses, and is
situated in the city of Heerlen.
Photo: Carisven Heerlen (© Novem – Hans Pattist)
THE LABORATORY BUILDING
“LA CASA INTELLIGENTE” – ROME, ITALY
La casa intelligente is located in
the ENEA centre in Casaccia,
Rome, in Italy. Many energy
efficient technologies and nation-
al programmes are developed
here for the residential sector.
modern heaters, which work at lowertemperatures and have more sophisticatedcontrols. A direct expansion ventilationsystem has also been installed, using anenvironmentally friendly gas instead of wateras a thermovector, unlike traditional appara-tus.
This heating system is connected to thesecurity system, shutters, lighting, program-ming of internal devices and technologicalsystems. The kitchen appliances interact tominimize energy consumption and therefrigerator has the added capability of beingequipped to remind the user of the expirydate of food by reading the relevant barcodes. All of these instructions are givenusing a small user-friendly touch pad. Anexperimental programme is underway to lookat the issue of humidity, which in the Italianclimate, is an important parameter to consid-er in relation to masonry. Tests showed doorsto be quite air tight and the thermal comfortlevels of the building in winter demonstratedthe success of the building envelope design.
Contact Information:ENEAArch. G.FasanoTel: +39 06 3048 4827Fax: +39 06 3048 [email protected]
This laboratory building, was funded withinthe framework of the MICA-ENEAprogramme (MICA is the Italian Ministry forIndustry, ENEA is the Italian Committee forEnergy and Environment). This case studypresents the application of systems andtechnological devices suitable for adoption inthe medium term for everyday use in theconstruction industry.
This two storey detached building has anarea of 900 m3 and is quite traditional, but thebrickwork consists of alveolater bricks. Thesebricks are manufactured with a mass of smallair cavities diffused throughout, making thebrick lighter and giving better thermalinsulation characteristics to the walls. Thewindows are equipped with electro-chromicinsulating glass featuring electronicallyadjustable light and power transmissionallowing regulation of the amount of light andheat passing through the window.
A radiant floor panel system has beeninstalled which circulates water at lowtemperatures for heating and higher temper-atures for cooling, to reduce energy con-sumption. This involves the use of more
VILLA WÅHLIN – STOCKSUND, SWEDEN
The Villa Wåhlin is a demonstra-
tion project for STEP, the new,
lighter structure building system.
The exterior walls consist of large
polystyrene block elements that
are connected to each other with
U-shaped shield metal profiles.
This two storey residential building has largesouth facing windows. A balanced ventilationairhandling unit is installed in the heatedcrawl space beneath the building. Thiscombination supplies the building with freshair and heat.
The crawl space is heated, insulated andradon tight at ground level. The air supply isfrom a balanced ventilation source with anair/air heat pump that works by using theheat from the returned air to preheat the
Contact information:Arkitekt SARMr. Per WåhlinTel: +46 8 858 585, +46 70 565 [email protected]
supply air. Warm air is supplied to the crawlspace, heating the floor, and flows through agap at the edge of the floor into the roomsabove. However it was found that heating ofthe two remaining floors was insufficient andadditional heating was required.
Photo: Per Wåhlin
THE SIBELIUS HALL – LAHTI , F INLAND
Sibelius Hall is the largest
wooden building constructed in
Finland for over one hundred
years.
The complex which is nearly 90,000 m3 is aconference centre and concert venue.Facilities include a main hall with 1250 seats,the forest hall which is a 1000 m2 lobby, arenovated carpentry factory which acts as a1400 m2 exhibition space, and meeting andlecture rooms.
In Finland wood has always been a popularbuilding material, both inside and outside.The Sibelius Hall represents the furtherdevelopment of timber constructiontechnology. The building contains manyspecial wooden elements and uses newinnovative approaches and solutions. Forexample, the facades of the conferencecentre and concert hall are made of sandfilled wooden structures and glass. Recentresearch in Finland has shown that use ofwood impacts positively on indoor climateand comfort.
THE AALTOALVARI WATER SPORT CENTRE
– JYVÄSKYLÄ, F INLAND
The AaltoAlvari is a water sport
centre originally designed by the
world famous Finnish architect
Alvar Aalto.
tion, are much greater than in other types ofbuildings. The evaporation of water from thepools consumes a substantial amount of theenergy. An essential task for the buildingservice system is to manage the moistureload.
The ThermoNet®-Indoor swimming hallsystem is an integrated system, where thedifferent demands of pool areas, dressingrooms and shower areas have been takeninto account. The system is flexible andfunctions according to users’ needs.Lifecycle costs are optimised and theenvironmental impact is minimised.
Contact information:ABB Installaatiot OyMr. Antti Saari/ Mr. Ilkka SaloTel: +358 10 [email protected]@fi.abb.com
The centre has a total area of 64,900 m3 andoffers excellent swimming and water sportsfacilities as well as a modern spa.
Between 1998 and 2000 a major recon-struction and renovation programme wasundertaken in the AaltoAlvari. A ThermoNet®low temperature system was installed. Afterrenovation, the heat energy demand wasreduced by 20% and the indoor climate andcomfort levels have been improved consider-ably.
Due to the nature of indoor swimmingpools and spas, the heat energy require-ments, and electricity and water consump-
Contact information:ABB Installaatiot OyMr. Antti Saari/Mr. Ilkka SaloTel: +358 10 [email protected]@fi.abb.com
The building is heated and cooled with aThermoNet® system, with district heatingand cooling networks supplying energy to theHall. Cooling is achieved by utilizing the localindustry process water via absorption chillers.Waste heat from the system is recovered byreturn to the district heating system.
In a venue of this sort it was essential togive due consideration to the acoustics of themain hall. The materials and even thefurniture have all been chosen with this inmind. In this kind of environment it is alsoessential that the cooling system is silent.The echo chambers at the sides of the hall,along with the doors and curtains, allow foradjustments to the acoustics of the hall whenrequired.
Photo: Veikko Niemelä
Photo: Juha Sorri
THE LOWEX RESEARCH
PROGRAMME
LowEx, the international low temperatureheating systems research programme, is partof the International Energy Agency’s (IEA)Energy Conservation in Buildings and Com-munity Systems programme (ECBCS).
The aim of the programme is to promoterational use of energy by encouraging the useof more efficient low temperature heatingsystems for heating and cooling of buildings.The programme will result in the productionof a guidebook for designers on low tempera-ture heating systems. It will outline theadvantages and constraints of the systems
and components required and provideinformation on analysis, planning and selec-tion tools. This book will be completed by theend of 2003.
The programme is coordinated by VTT,Finland. The coordinating group consist of amanagement team which has the followingpartners: ABB Installaatiot Oy, Are Oy,Development Centre For Finnish BuildingServices Ltd, The Finnish District HeatingAssociation (FDHA), Tekes the NationalTechnology Agency, Uponor Suomi Oy,VTT Building and transport and YIT.
Layout: Tuija Karppanen, printed by Aksidenssi Oy, 3,000 pieces, 6/2002
This brochure is a product of theAnnex 37 working group and hasnot been submitted for approvalof the ECBCS Executive commit-tee. ECBCS is therefore notresponsible for the contents ofthis newsletter.
IEA ECBCS
MORE INFORMATION
ABOUT THE
PROGRAMME:
Up to date information about theparticipants and the progress of theresearch program available on theweb page:
www.vtt.fi/rte/projects/annex37
COORDINATORS OF THE
PROGRAMME:
VTT Building and transportOperating agent: Markku [email protected]: Åsa [email protected] 180402044 VTTTel: +358 9 456 4744Fax: +358 9 455 2408
THE PARTICIPATING
COUNTRIES ARE
Canada DenmarkFinland FranceGermany ItalyJapan The NetherlandsNorway PolandSweden