IS TEMPERIERUNG ENERGY EFFICIENT? THE APPLICATION OF AN OLD NEW HEATING SYSTEM TO HERITAGE BUILDINGS

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LÓPEZ, M.; YÁÑEZ, A.; GOMES DA COSTA, S.; AVELLÀ, L., (Coord.). Actas del Congreso Internacional de Eficiencia Energética y Edificación Histórica / Proceedings of the International Conference on Energy Efficiency and Historic Buildings (Madrid, 29-30 Sep. 2014). Madrid: Fundación de Casas Históricas y Singulares y Fundación Ars Civilis, 2014. ISBN: 978-84-617-3440-5

Edited by

Fundación de Casas Históricas y Singulares Fundación Ars Civilis

Coordinated by

Mónica López Sánchez. Fundación Ars Civilis

Ana Yáñez Vega. Fundación de Casas Históricas y Singulares Sofia Gomes da Costa. Fundación de Casas Históricas y Singulares Lourdes Avellà Delgado. Fundación Ars Civilis

© Copyright

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PRESENTACIÓN ... - 11 -

Eficiencia energética y edificación histórica: un reto del presente... - 13 -

Cristina Gutiérrez-Cortines y Mónica López Sánchez. Fundación Ars Civilis Eficiencia energética y edificación histórica: un reto del futuro ... - 14 -

Ana Yáñez Vega. Fundación de Casas Históricas y Singulares Committees ... - 15 -

Programme ... - 16 -

Governance, management, participation and mediation... 21

-SUSTAINABLE ENERGY ACTION FOR WORLD HERITAGE MANAGEMENT ... - 22 -

RONCHINI, C.; POLETTO, D. ENERGY EFFICIENCY AND URBAN RENEWAL OF A UNESCO-LISTED HISTORICAL CENTER: THE CASE OF PORTO ... - 38 -

SANTOS, Á.; VALENÇA, P.; SEQUEIRA, J. HISTORICAL HERITAGE: FROM ENERGY CONSUMER TO ENERGY PRODUCER. THE CASE STUDY OF THE ‘ALBERGO DEI POVERI’ OF GENOA, ITALY ... - 45 -

FRANCO, G.; GUERRINI, M.; CARTESEGNA, M. IMPROVING ENERGY EFFICIENCY IN HISTORIC CORNISH BUILDINGS – GRANT FUNDING, MONITORING AND GUIDANCE ... - 61 -

RICHARDS, A. ENERGY EFFICIENCY AND BUILDINGS WITH HERITAGE VALUES: REFLECTION, CONFLICTS AND SOLUTIONS ... - 75 -

GIANCOLA, E.; HERAS, M. R. PROPUESTA METODOLÓGICA PARA LA REHABILITACIÓN SOSTENIBLE DEL PATRIMONIO CONTEXTUAL EDIFICADO. EL CASO DEL CENTRO HISTÓRICO DE LA CIUDAD DE MÉRIDA, YUCATÁN / Methodological proposal for the sustainable rehabilitation of context heritage building. The case of the historic downtown of Merida, Yucatan ... - 82 -

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Traditional and technological knowledge: concepts, techniques, practices, uses,

materials, methodologies ... 99

-SUSTAINABLE REFURBISHMENT OF HISTORIC BUILDINGS: RISKS, SOLUTIONS AND

BEST PRACTICE ... - 100 -

HEATH, N.

EFICIENCIA ENERGÉTICA Y VALORES PATRIMONIALES. LECCIONES DE UNA

INVESTIGACIÓN Y UN SEMINARIO / Energy efficiency and heritage values. Lessons of

a Research and a Seminar ... - 110 -

GONZÁLEZ MORENO-NAVARRO, J. L.

ARCHITECTURAL INTEGRATION OF PHOTOVOLTAIC SYSTEMS IN HISTORIC DISTRICTS.

THE CASE STUDY OF SANTIAGO DE COMPOSTELA ... - 118 -

LUCCHI, E.; GAREGNANI, G.; MATURI, L.; MOSER, D.

HISTORIC BUILDING ENERGY ASSESSMENT BY MEANS OF SIMULATION TECHNIQUES ... - 135 -

SOUTULLO, S.; ENRIQUEZ, R.; FERRER, J. A.; HERAS, M. R.

DESIGN OF A CONTROL SYSTEM FOR THE ENERGY CONSUMPTION IN A WALL-HEATED

CHURCH: SANTA MARIA ODIGITRIA IN ROME ... - 145 -

MANFREDI, C.; FRATERNALI, D.; ALBERICI, A.

EXEMPLARY ENERGETICAL REFURBISHMENT OF THE GERMAN ACADEMY IN ROME

"VILLA MASSIMO" ... - 160 -

ENDRES, E.; SANTUCCI, D.

SISTEMA MÓVIL INTEGRADO PARA LA REHABILITACIÓN ENERGÉTICA DE EDIFICIOS: LÁSER 3D, TERMOGRAFÍA, FOTOGRAFÍA, SENSORES AMBIENTALES Y BIM / Integrated mobile system for building energy rehabilitation: 3D laser, termography, fotography,

environmental sensors and BIM ... - 169 -

SÁNCHEZ VILLANUEVA, C.; FILGUEIRA LAGO, A.; ROCA BERNÁRDEZ, D.; ARMESTO GONZÁLEZ, J.; DÍAZ VILARIÑO, L.; LAGÜELA LÓPEZ, S.; RODRÍGUEZ VIJANDA, M.; NÚÑEZ SUÁREZ, J.; MARTÍNEZ GÓMEZ, R.

CONSECUENCIAS CONSTRUCTIVAS Y ENERGÉTICAS DE UNA MALA PRÁCTICA. ARQUITECTURAS DESOLLADAS / Energy and constructive consequences of a bad

practice. Skinned architectures ... - 186 -

DE LUXÁN GARCÍA DE DIEGO, M.; GÓMEZ MUÑOZ, G.; BARBERO BARRERA, M.; ROMÁN LÓPEZ, E.

EL BIENESTAR TÉRMICO MÁS ALLÁ DE LAS EXIGENCIAS NORMATIVAS. DOS CASOS. DOS ENFOQUES / Thermal comfort beyond legislation. Two examples. Two

approaches ... - 201 -

DOTOR, A.; ONECHA, B.; GONZÁLEZ, J. L.

LA MONITORIZACIÓN Y SIMULACIÓN HIGROTÉRMICA COMO HERRAMIENTA PARA LA MEJORA DEL CONFORT, PRESERVACIÓN Y AHORRO ENERGÉTICO DE ESPACIOS

PATRIMONIALES. EL CASO DE LA IGLESIA DE SAN FRANCISCO DE ASIS, MORÓN DE LA FRONTERA / Measurement and hygrothermal simulation model, a tool to enhance thermal comfort, preservation and saving energy of heritage site. Case study: the

church of San Francisco of Asís in Morón de la Frontera ... - 210 -

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TERESE3: HERRAMIENTA INFORMÁTICA PARA LA EFICIENCIA ENERGÉTICA MEDIANTE LA SIMULACIÓN CALIBRADA DE EDIFICIOS / TERESE3_{: informatic tool for the energetic}

efficiency through the calibrated simulation of buildings ... - 226 -

GRANADA, E.; EGUÍA, P.; MARTÍNEZ, R.; NÚÑEZ, J.; RODRÍGUEZ, M.

EFICIENCIA ENERGÉTICA Y ANÁLISIS TÉRMICO PARA SISTEMAS DE AIRE

CENTRALIZADO: UN CASO DE ESTUDIO / Energy Efficiency and thermal analysis for

centralized air heating systems: a case study ... - 238 -

MARTÍNEZ-GARRIDO, M. I.; GOMEZ-HERAS, M.; FORT, R.; VARAS-MURIEL, M. J.

ANALISIS ENERGETICO DEL MUSEO DE HISTORIA DE VALENCIA MEDIANTE DISTINTAS HERRAMIENTAS DE SIMULACIÓN / Energy assessment of the History Museum of

Valencia using various simulation tools ... - 249 -

TORT-AUSINA, I.; VIVANCOS, J.L.; MARTÍNEZ-MOLINA, A.; MENDOZA, C. M.

APROVECHAMIENTO SOLAR PASIVO EN LA RETÍCULA URBANA DE LA CIUDAD HISTÓRICA. EL CASO DE CÁDIZ / Passive solar gains in the urban grid of the historic

city. The case study of Cadiz ... - 257 -

SÁNCHEZ-MONTAÑÉS, B.; RUBIO-BELLIDO, C.; PULIDO-ARCAS, J. A.

TECHNICAL SYSTEM HISTORY AND HERITAGE: A CASE STUDY OF A THERMAL POWER

STATION IN ITALY ... - 275 -

PRETELLI, M.; FABBRI, K.

ANALISIS ENERGÉTICO Y PROPUESTAS DE MEJORA DE UNA CASA EN REQUENA MEDIANTE PROGRAMAS DE SIMULACIÓN / Energy analysis and improvement

proposal of a house in Requena (Spain) using simulation software ... - 281 -

TORT-AUSINA, I.; VIVANCOS, J.L.; MARTÍNEZ-MOLINA, A.; MENDOZA, C. M.

UNA REVISIÓN DE PUBLICACIONES EN EDIFICIOS DESDE EL ASPECTO ENERGÉTICO / A

review of papers in buildings from the energetic perspective ... - 292 -

TORT-AUSINA, I.; MARTÍNEZ-MOLINA, A.; VIVANCOS, J.L.

MORTEROS MIXTOS DE CAL Y CEMENTO CON CARACTERÍSTICAS TÉRMICAS Y ACÚSTICAS MEJORADAS PARA REHABILITACIÓN / Lime-cement mixture with

improved thermal and acoustic characteristics for rehabilitation ... - 303 -

PALOMAR, I.; BARLUENGA, G.; PUENTES, J.

NEAR ZERO ENERGY HISTORIC BUILDING. TOOLS AND CRITERIA FOR ECOCOMPATIBLE

AND ECOEFFICIENT CONSERVATION ... - 318 -

BAIANI, S.

INTEGRANDO RENOVABLES EN LA CIUDAD HEREDADA: GEOTERMIA URBANA /

Integrating renewable in the inherited city: urban geothermal ... - 329 -

SACRISTÁN DE MIGUEL, M. J.

ANÁLISIS Y PROPUESTAS DE MEJORA DE LA EFICIENCIA ENERGÉTICA DE UN EDIFICIO HISTÓRICO DE CARTAGENA: ANTIGUO PALACIO DEL MARQUÉS DE CASA-TILLY / Analysis and proposals for improving the energy efficiency of a historical building in

Cartagena: the former Palace of the Marquis of Casa-Tilly ... - 344 -

COLLADO ESPEJO, P. E.; MAESTRE DE SAN JUAN ESCOLAR, C.

REHABILITACIÓN ENERGÉTICA DE EDIFICIOS DE VIVIENDAS BAJO EL PLAN ESPECIAL DE PROTECCIÓN DEL PATRIMONIO URBANÍSTICO CONSTRUIDO EN DONOSTIA-SAN SEBASTIÁN / Building energy retrofit of dwellings under the special plan of urban

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- 8 - MARTÍN, A.; MILLÁN, J. A.; HIDALGO, J. M.; IRIBAR, E.

IS TEMPERIERUNG ENERGY EFFICIENT? THE APPLICATION OF AN OLD-NEW HEATING

SYSTEM TO HERITAGE BUILDINGS ... - 366 -

DEL CURTO, D.; LUCIANI, A.; MANFREDI, C.; VALISI, L.

TERMOGRAFÍA INFRARROJA Y EDIFICIOS HISTÓRICOS ... - 380 -

MELGOSA, S.

SIMULATION MODEL CALIBRATION IN THE CONTEXT OF REAL USE HISTORIC

BUILDINGS ... - 388 -

ENRÍQUEZ, R.; JIMÉNEZ, M.J.; HERAS, M.R.

THE THERMOPHYSICAL CHARACTERIZATION OF TECHNICAL ELEMENTS IN THE

HISTORIC ARCHITECTURE: EXPERIENCES IN PALERMO ... - 397 -

GENOVA, E.; FATTA, G.

ENERGY EVALUATION OF THE HVAC SYSTEM BASED ON SOLAR ENERGY AND

BIOMASS OF THE CEDER RENOVATED BUILDING ... - 407 -

DÍAZ ANGULO, J. A.; FERRER, J. A.; HERAS, M. H.

Legal and technical regulation and historic buildings ... 419

-OLD BUILDING, NEW BOILERS: THE FUTURE OF HERITAGE IN AN ERA OF ENERGY

EFFICIENCY ... - 420 -

JANS, E.; ICOMOS, M.; KOPIEVSKY, S.; AIRHA, M.

HISTORIC WINDOWS: CONSERVATION OR REPLACEMENT. WHAT'S THE MOST

SUSTAINABLE INTERVENTION? LEGISLATIVE SITUATION, CASE STUDIES AND CURRENT

RESEARCHES ... - 432 -

PRACCHI, V.; RAT, N.; VERZEROLI, A.

ENERGY RETROFIT OF A HISTORIC BUILDING IN A UNESCO WORLD HERITAGE SITE: AN

INTEGRATED COST OPTIMALITY AND ENVIRONMENTAL ASSESSMENT... - 450 -

TADEU, S.; RODRIGUES, C.; TADEU, A.; FREIRE, F.; SIMÕES, N.

PARQUE EDIFICADO O PATRIMONIO EDIFICADO: LA PROTECCIÓN FRENTE A LA INTERVENCIÓN ENERGÉTICA. EL CASO DEL BARRIO DE GROS DE SAN SEBASTIÁN / Built Park or Built Heritage: Protection against energy intervention. The case of Gros

district of San Sebastian ... - 464 -

URANGA, E. J.; ETXEPARE, L.

SIMULTANEOUS HERITAGE COMFORT INDEX (SHCI): QUICK SCAN AIMED AT THE SIMULTANEOUS INDOOR ENVIRONMENTAL COMFORT EVALUATION FOR PEOPLE AND

ARTWORKS IN HERITAGE BUILDINGS ... - 478 -

LITTI, G.; FABBRI, K.; AUDENAERT, A.; BRAET, J.

PROBLEMÁTICA DE LA POSIBLE CERTIFICACIÓN ENERGÉTICA CON CE3_{X DEL}

PATRIMONIO ARQUITECTÓNICO: EL CASO DEL ALMUDÍN DE VALENCIA / Difficulties found in the possible energy certification of heritage by using the CE3X software: the

case of El Almudín of Valencia ... - 495 -

CUARTERO-CASAS, E.; TORT-AUSINA, I.; MONFORT-I-SIGNES, J.; OLIVER-FAUBEL, E. I.

PROTOCOL FOR CHARACTERIZING AND OPTIMIZING THE ENERGY CONSUMPTION IN

PUBLIC BUILDINGS: CASE STUDY OF POZUELO DE ALARCÓN MUNICIPALITY ... - 506 -

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Promotion, training, education ... 513

-THE WORK OF -THE SUSTAINABLE TRADITIONAL BUILDINGS ALLIANCE AND AN

INTRODUCTION TO THE GUIDANCE WHEEL FOR RETROFIT ... - 514 -

MAY, N.; RYE, C.; GRIFFITHS, N.

TRAINING OF EXPERTS FOR ENERGY RETROFIT AT THE FRAUNHOFER CENTRE FOR THE ENERGY-SAVING RENOVATION OF OLD BUILDINGS AND THE PRESERVATION OF

MONUMENTS AT BENEDIKTBEUERN ... - 528 -

KILIAN, R.; KRUS, M.

SPECIALIZED ENERGY CONSULTANTS FOR ARCHITECTURAL HERITAGE ... - 535 -

DE BOUW, M.; DUBOIS, S.; HERINCKX, S.; VANHELLEMONT, Y.

RENERPATH: METODOLOGÍA DE REHABILITACIÓN ENERGÉTICA DE EDIFICIOS PATRIMONIALES / RENERPATH: Methodology for Energy Rehabilitation of Heritage

Buildings ... - 543 -

PERÁN, J. R. ; MARTÍN LERONES, P.; BUJEDO, L. A.; OLMEDO, D.; SAMANIEGO, J.; GAUBO, F.; FRECHOSO, F.; ZALAMA, E.; GÓMEZ-GARCÍA BERMEJO, J.; MARTÍN, D.; FRANCISCO, V.; CUNHA, F.; BAIO, A.; XAVIER, G.; DOMÍNGUEZ, P.; GETINO, R.; SÁNCHEZ, J. C.; PASTOR, E.

LEVANTAMIENTOS ARQUITECTÓNICOS EN EL MEDIO RURAL / Architectural surveys in

rural areas ... - 553 -

HIDALGO, J.M.; MILLÁN, J. A.; MARTÍN, A.; IRIBAR, E.; FLORES, I.; ZUBILLAGA, I.

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DEL CURTO, D.; LUCIANI, A.; MANFREDI, C.; VALISI, L.

DEL CURTO, D.: Laboratorio di Analisi e Diagnostica del Costruito, DAStU, Politecnico di Milano. Milano – Italia. davide.delcurto@polimi.it

LUCIANI, A.: Laboratorio di Analisi e Diagnostica del Costruito, DAStU, Politecnico di Milano. Milano – Italia. andrea.luciani@polimi.it

MANFREDI, C.: Laboratorio di Analisi e Diagnostica del Costruito, DAStU, Politecnico di Milano. Milano – Italia. carlo.manfredi@polimi.it

VALISI, L.: Laboratorio di Analisi e Diagnostica del Costruito, DAStU, Politecnico di Milano. Milano – Italia. luca.valisi@polimi.it

ABSTRACT

Temperierung consists in the installation of pipes circulating hot water (40-60°C) below the surface of the wall at one or more different heights from the floor, forming a heated band at man-height. Similarly to the floor heating, heat is emitted in part by IR radiation at low frequency, in part is transferred to the air by conduction inside the wall and then by convection to the air along the wall. The experience of the Landesstelle für die Nichtstaatlichen Museen in Bayern since the 1980's, highlights that the best results are gained when the two purposes of heating and preservation are properly balanced [1].

The paper presents an update of the discussion on Temperierung, following the most recent studies evaluating the system on the basis of data collected on field, after 30 years of installations and debates [2]. Along with the question of how Temperierung is effective to set an indoor climate suitable for preservation, the authors consider now the impact of Temperierung on users' comfort and energy consumption.

Beside recent literature, the discussion is based on the experimental data from the ongoing monitoring of Palazzo Pallavicino-Ariguzzi in Cremona. The Palazzo was built between 14th and 19th century and is nowadays used as an international violin-making school and a music academy. A Temperierung system was installed in 2006 and monitored since 2013 by measuring outdoor and indoor air temperature and relative humidity, wall surface temperatures and radiant heat.

The results of the first season of monitoring allow a discussion on some beliefs concerning the use of Temperierung in heritage buildings.

Key words: Temperierung, indoor climate, monitoring, energy efficiency

1. INTRODUCTION

Temperierung consists in the installation of pipes circulating hot water (40-60°C) below the surface of the wall, forming a band of heated band at man’s height. In case of the restoration of historic buildings with fine masonry surfaces, the tubes can also be applied on the wall surface. Similarly to the floor heating, the heat is emitted in part as IR radiation at low frequency, in part is transferred to air by conduction inside the wall and then by convection to the air close to the wall [3].

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and the best results are obtained by the combination of the two purposes. The main experiences are collected in the Eureka project / Eurocare "PREVENT" attended by partners from Austria, Czech Republic, Italy, Slovenia and Germany The book of the results is still a kind of "manifesto" of Temperierung [1] and states some key points at the base of the project "PREVENT", then incorporated and developed by subsequent research: 1) the building envelope plays a key role in regulating and stabilizing the indoor climate; 2) the slow variation of the indoor climate is a key requirement of the project; 3) the international standards about the climatic values cannot be considered universally valid because they do not take into account the local and seasonal conditions of each place, the typology and constructive features of each building or the type of heating and air conditioning [4].

More recently, Temperierung has been studied in the context of the European projects "Friendly Heating" and "Climate for Culture", in addition to the work of the Technische Käferhaus Büro GmbH in Wien [5]. Ongoing research at the Fraunhofer Institute for Building Physics and activities promoted by Landesstelle für die nichtstaatlichen Museen in Bayern with the project "Temperierung Heating as a Tool for Preventive Conservation – An Assessment" should also be mentioned [2]. Besides the evaluation of Temperierung as a tool for preventive conservation, current research is focused on two aspects: 1) the evaluation of the energy behaviour of the system (Temperierung is energy-efficient?); 2) the effectiveness of Temperierung to define hygrothermal comfort conditions for users.

The availability of experimental data is a key issue to achieve good results and to renew the debate on Temperierung which, in the recent past, was rarely based on experimental data. For this reason, a third issue is the definition of an internationally shared measurement protocol [6].

This paper presents the first results of the monitoring of the internal climate of the Palazzo Pallavicini-Ariguzzi in Cremona, where a Temperierung system was installed during the general restoration of the building. The building is quite representative of the Italian situation, where Temperierung has been employed in a number of historic buildings over the last thirty years as a possible alternative to the systems of heating air or radiant floor. This trend must be connected to the rise of conservation as a primary goal of architectural restoration and to the spread of the idea that the amount of matter which is preserved, may be a way to state the quality of a restoration project: technical devices, especially those for heating and air-conditioning, may cause serious damage to walls, decorations, floors and ceilings, and sometimes even to the fragile structure of historic buildings (holes, channels, partial demolition). That is why Italian designers were more interested in Temperierung as a way to limit the damage to the existing building, rather than as a device for preventive conservation [7].

The building nowadays known as Palazzo Pallavicino-Ariguzzi in Cremona (approx. 5,000 square meters, 20,000 cubic meters) is the result of a long process of aggregation of different smaller buildings from the Middle Age, the 17th and 18th century and the Modern Age. Temperierung was installed as a heating system between 2002 and 2005, but has been in operation only since autumn 2010, when the building became the headquarters of the Professional Institute for the International Violin Making and Woodworking Handicrafts (IPIALL) [8,9].

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The pipes are coated with a layer of lime plaster applied over the existing plaster and finished with lime stucco and marble powder. The channelling of the electrical system is placed in the bottom of the wall, between the two pipes of the lower circuit, protected by a brass plate. An additional single pipe is also installed at the base of some interior walls (e.g. in the 18th-century wing).

The pipework has been designed in detail to follow and exploit the building structure: the dispersions due to the windows and to the limited thickness of the wall are compensated by putting the pipes in place as a coil in the wall sections under the windows and the frames of the new internal doors have been designed to accommodate the copper pipes.

The heating system is connected to the district heating. The heat is distributed to local collectors through a primary circuit running underground, along the façades of the inner courtyard. To keep the efficiency constant, the local circuits have an average length of 60m.. The water circulates at 40-45°C. Although it was planned in the project, an automatic regulation of the system has never been installed.

2. METHODOLOGY

Image 1: plan of first floor, ground floor and under ground floor of Palazzo Pallavicino. All the highlighted rooms have been monitored during this study, but only the rooms highlighted in red are described in the

article

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The study was focused on 8 significant rooms and indoor environments (Image 1) for a total of 36 measure points; sensors are generally positioned around 2,5-3m from the ground, to avoid disturbance to the users’ activities.

Following current European standards EN 15758:2010 [14] e EN 16242:2012 [15], air temperature (T) and relative humidity (RH) are measured in all the selected rooms by high-precision thermistors (accuracy: ±0.2°C, resolution 0,1°C) and capacitive polymers (accuracy: ±2%, resolution 0,1%)

Surface temperature (Ts) is monitored in the heated rooms, generally in the midpoint between two water pipes, in order to measure the average temperature induced by the heating system to the plastered surface (Image 2).

Image 2: lecture hall, 19/12/2013, Ts range: 20,5-34°C; surface temperature is measured with a contact sensor between the delivery and return pipe of the upper circuit, as the average of the two temperatures

The headmaster’s office was surveyed in depth. Here, besides air temperature and relative humidity, surface temperatures are monitored on each external wall at two different heights [6]: the first measure-point is placed in the midpoint between the two upper pipes, the second one is around one meter higher, in order to understand if the surface temperature of the wall is still influenced by the heating flow. On the outer face of one wall there are two additional measure points, corresponding to the two measure points on the inner side (Images 3 and 4). Furthermore a black-globe thermometer, placed 2.5m from the ground in the middle of the room, is used to measure and verify the radiant effect which is expected from the Temperierung system.

Infrared imaging was used to obtain a qualitative and quantitative description of surface temperatures and to describe the hygrothermal interactions between the indoor environment, walls and the heating system, both during cold seasons, with the heating on, and warm seasons, with the heating off.

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The energy consumption of the heating system was measured by a pulse counter installed in the heat-exchanger with the local district heating.

Images 3-4: headmaster’s office, indoor and outdoor,19/12/2013, Ts ranges: 15,5-24,5°C and 20,5-24,5°C; surface temperatures are measured at two different heights, both on the inner and on the outer side of the

wall; each arrow points out one measure point (one covered by an inlaid panel)

3. RESULTS

Comparing data gathered from January to March 2014 in three different rooms, the lecture hall on the ground-floor and two classrooms at the first floor facing south (one on the inner court, the other one on the street), some interesting differences in the hygrothermal trends can be observed. The following graphs (Images 5-6-7) show outdoor RH and T (upper and lower grey line), indoor RH and T (blue line and red line) and surface temperature nearby the pipes of the Temperierung (green line).

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- 371 - Image 5: classroom, first floor, north wing; outdoor RH and T (upper and lower grey lines), indoor RH and T

(blue and red line) and surface temperature nearby a Temperierung pipe (green line)

Image 6 shows the values surveyed in one of those classrooms where the Temperierung system was combined with a fan coil unit due to the uncomfortable low temperatures that were observed during winters. In this classroom infrared imaging has detected a low extension of the pipework, since two partition walls, without any pipe, were added after the installation of the heating system (this part of the building was initially thought as one large room but it was later divided into three smaller classrooms). The sudden peaks in the air T line (red line) are thus probably due to the fan coil unit switching on. As a result, corresponding RH drops can be observed, since the unit has no humidification apparatus and the air gets drier. Even in a rather mild winter, the simultaneous action of the two systems, inefficiently controlled and combined with the solar radiation of the south-facing room, results in quite high average temperatures, with anomalous episodes of useless overheating up to 28°C.

The sensor, placed 3m from the ground, is exposed to higher temperatures compared to the users at floor level due to air stratification, showing that an air heating system cannot be efficient in such a building, where a quite relevant distance between the floors cause the upper part of the rooms, without users’ presence, to be the warmest. Furthermore, air excessively dried and sudden RH fluctuations can result in mechanical decay of hygroscopic materials, e.g. the wooden ceiling in this room which is exposed to the riskiest hygrothermal stresses.

Hygrothermal conditions in the lecture hall are shown in Image 7. The room is very large and well-equipped with Temperierung pipework into the walls. Since it is subjected to crowding, during the refurbishment a central ventilation system was designed (with an air handler unit in the lower floor) but it seems to be in operation only occasionally. The effects on the hygrothermal variations are similar to those caused by the fan coil unit in the classroom (peaks in T and drops in RH) but they are much more limited due to the huger volume of the room.

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system, while the Temperierung systems seems to keep the temperatures quite homogenous and comfortable in the rest of the room.

Image 6: classroom, first floor, south wing; outdoor RH and T (upper and lower grey lines), indoor RH and T (blue and red line) and surface temperature nearby a Temperierung pipe (green line)

Image 7: lecture hall, ground floor; outdoor RH and T (upper and lower grey lines), indoor RH and T (blue and red line) and surface temperature nearby a Temperierung pipe (green line); highlighted in yellow the

day 30/1/2014

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heat dispersion and cold air infiltration from the outside. An infrared image taken in March 8th 2013 (Image 10) shows the distribution of the pipes in the north-facing wall of this room.

As described in paragraph 2, the headmaster’s office was analysed in depth: air T and RH were monitored, as well as surface temperatures in many different points and the radiant temperature through black-globe thermometer. This way significant data were gathered about how the Temperierung system works.

Firstly, the temperature detected by the black-globe thermometer (placed in the middle of the room 2,5m from the ground) was almost overlapping the air temperature detected by a sensor placed in the same point. This information could mean that, at least in this point, the system is not able to influence significantly an object by radiation. The radiant effect of the system, probably combined with a convective flow, is likely limited to the perimeter of the room, close to the pipework, as suggested by the psychrometry in Image 9.

The graph in Image 11 describes the thermal behaviour and the environmental interactions of the 3 outer walls in the week from January 27th_{to February 3}rd_{2014. The air temperature (purple} line) and the outdoor temperature (grey line) are compared with the surface temperatures of the walls detected nearby the pipes (Ts 10b, Ts 11b, Ts 13b) and 1 meter above the pipes (Ts 10a, Ts 11a, Ts 13a). The temperature measured nearby the pipe along the inner court (Ts10b, measure point 10 in Image 9) remains 1°C lower than those measured on the other pipes (Ts11b and Ts13b, measure points 11 and 13 in Image 9), probably due to the larger dispersion caused by the heating-coil displacement of the pipes under the windows (see also Image 14).

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- 374 - Images 9-10: headmaster’s office, ground floor. Psychrometric mapping of 30/01/2014 and thermal image

of 8/3/2013, both with the heating system in operation; blue dots are the measure points

As shown in Image 10, the heat transmission from the pipes to the walls seems limited to the areas closest to the pipes, without affecting the other parts of the walls. As a result, the three surface temperatures measured 1 meter above the pipes (Ts 10a, Ts 11a, Ts 13a) are lower than the air temperature (purple line), which means that the heat dispersion through the walls is prevailing on the heat that is supposed to be transmitted by the pipes to the inner side of the walls. It is also interesting to notice what is causing the differences of temperatures between the measure points: Ts 13a and Ts11a are placed behind two inlaid panels which insulate them from the warm air of the room (see Image 3) while Ts 10a is not covered (see Image 14), it is influenced by heated air and it is thus measuring the equilibrium temperature between the inner surface of the wall and the indoor air. The cold areas behind the inlaid panels can be observed in the thermal images in Images 3, 10 and 14. The constant difference of less than 1°C between Ts 11a and Ts 13a is due to the different thickness of the walls influencing their transmittance: the former is higher than the latter because is measured on a thicker wall with lower transmittance.

Heat dispersion through the walls is worse nearby the pipes, which is one of the most criticised aspects of Temperierung systems. The graph in Image 12 tries to give a quantitative and qualitative description of this problem. As shown in Images 3 and 4, besides indoor and outdoor air temperature (purple line and grey line), not only the surface temperatures on the inner side of the wall (nearby the pipes, Ts13b, and 1m above, Ts 13a) are measured but also the corresponding surface temperatures on the outer side of the wall (nearby the pipes, Ts12b, and 1m above, Ts 12a). The difference between Ts 12b and Ts 12a is caused by the heat dispersion from the pipes towards the outside. That is why when operation temperature of the heating system begins to be lowered (already in February 19th_{) until it is switched off (March 20}th_{), the} difference between the two temperatures becomes thinner and thinner and afterwards the two lines are almost overlapping.

10

13

11

12 4

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- 375 - Image 11: headmaster’s office, ground floor, 27/1–3/2/2014; indoor air T (purple line) and outdoor T (grey

line) compared with surface temperatures of the walls nearby the pipes (Ts 10b, Ts 11b, Ts 13b) and with surface temperatures 1 meter above (Ts 10a, Ts 11a, Ts 13a)

Image 12: headmaster’s office, ground floor, 30/12/2013–14/4/2014; indoor air T (purple line) and outdoor air T (grey line) compared with inner surface T of the walls nearby the pipes (Ts 13b), inner surface T 1m above the pipes (Ts 13a), outer surface T nearby the pipes (Ts 12b) and outer surface T 1m above the pipes

(Ts 12a)

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glazed surfaces of the windows (Image 13 and 14). Thus, Temperierung designers nowadays use to insert an insulating layer behind the pipes in these critical areas [16].

The energy consumption of the heating system was 192109 kWh for the whole winter 2013-2014 (from October 15th to March 20th). As the heated area is approx. 3000 m2, the energy consumption of the Temperierung system was approx. 64 kWh/m2. It is an encouraging performance, particularly considering the above mentioned dispersion problem and the building typology with high ceilings (the energy consumption calculated on the volumes would be 14,5 kWh/m3_{per year). A key role in energy saving was probably played also by the interventions put} in place in the recent refurbishment (e.g. double windows and thermal insulation of the roofs). Nevertheless, it must be considered that this performance was obtained in a mild winter and that, for this reason, the heating system has been switched off one month in advance than usual.

4. CONCLUSIONS

As the scientific literature on Temperierung is still lacking of data collected on field to validate or contest the theoretical principles on which the system is based, the ongoing monitoring of Palazzo Pallavicino may offer a useful database for renewing the discussion.

The data show that the system slightly warm the inner surface of the wall and the warming effect is limited to the areas immediately close to the pipes. On the contrary, the heat flow through the wall section result in heat dispersion to the outside.

Image 13: facade of the north wing on the inner court, 16/1/2014, range Ts: 2-8°C; the white box highlights the windows of the headmaster’s office which are shown from inside in Image 13

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- 377 - Image 14: headmaster’s office, ground floor, 16/1/2014, range Ts: 18-24°C; the black arrow points out the

measure point Ts 10a

The data about energy consumption suggests that the system can be efficient when installed in historic buildings but it should be better discussed whether this performance resulted in a comfortable environment for users or not.

In the headmaster’s office and in the offices nearby, where workstations are close to the walls, the users tend to complain about hot temperatures in winter. On the contrary, in the classrooms at the first floor, where only two walls are equipped with pipes but an additional fan coil unit was installed, users complain about freezing, despite the graphs show that the average air temperatures inside the rooms are similar in the two situations. This may probably be related to the much larger extension of pipework installed in the office rooms (the ratio between pipework and floor surface is around 2,5m/m2_{in the headmaster’s office and around 1m/m}2_{in the} classroom). Nevertheless it shows that if properly designed and dimensioned, Temperierung may give positive results for users’ comfort.

On this point, the indoor climate monitoring of Palazzo Pallavicino has highlighted that unbalanced and uncomfortable conditions are mainly due to the lack of a good regulation and control system, since it is impossible to obtain a local adjustment of heat flow and temperature.

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5. REFERENCES

[1]. Kotterer, M., Großeschmidt, H., Boody, F.P., Kippes, W. (Eds.). (2004). Klima in Museen und

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[2]. VV.AA. (2014). Die Temperierung. Beiträge zum aktuellen Forschungsstand. Munich: Volk Verlag.

[3]. Großeschmidt, H. (2004).The tempered building: Renovated architecture – Comfortable rooms – A “giant display case". In Kotterer, M., Großeschmidt, H., Boody, F.P., Kippes, W. (Eds.). Klima in Museen und historischen Gebäuden: Die Temperierung / Climate in Museums and Historical Buildings:

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[9]. Grimoldi, A. (2014). Historische Gebäude und Heizanlagen: Erfahrungen mit der Temperierung in Norditalien. In VV.AA. Die Temperierung. Beiträge zum aktuellen Forschungsstand (pp.100-110). Munich: Volk Verlag

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[12]. Del Curto, D., Luciani, A., Manfredi, C., Valisi, L. P. (2011). Historic analysis and climate monitoring: an integrated approach to the study and management of Villa Reale in Milan. In Krüger, M. (Ed.) Cultural Heritage Preservation. EWCHP 2011. Proceedings of the European Workshop on Cultural Heritage Preservation. Berlin, Germany, September 26 to 28, 2011 (pp. 70-77). Stuttgart: Fraunhofer IRB Verlag.

[13]. Manfredi, C., Luciani, A., Del Curto, D., Valisi, L. (2014). The case of ltaly: Energy efficiency and preservation - Two challenges for Temperierung. In VV.AA. Die Temperierung. Beiträge zum aktuellen Forschungsstand (pp.82-92). Munich: Volk Verlag

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- 379 - [15]. CEN – European Committee for Standardization (2012). EN 16242:2012 Conservation of cultural

heritage - Procedures and instruments for measuring humidity in the air and moisture exchanges between air and cultural property

[16]. Fraternali, D., Manfredi, C., (2010). Tempering in Palazzo Viani Dugnani in Pallanza. The project of a climate control system. In Del Curto, D. (Ed.). Indoor environment and preservation. Climate control in museums and historic buildings / Ambiente interno e conservazione. Il controllo del clima nei musei e negli edifici storici (pp.119-126). Firenze: Nardini Editore.

[17]. Holmberg, J. (2004). Comparison of Tempering and Conventional Convection Heating. In Kotterer, M., Großeschmidt, H., Boody, F.P., Kippes, W. (Eds.). Klima in Museen und historischen Gebäuden: Die Temperierung / Climate in Museums and Historical Buildings: Tempering (pp. 99-106). Wien: Schloss Schönnbrunn Kultur

[18]. Huber, A. (2014). „Warme Wände" oder „warme Luft"? Das Raumklimaverhalten bei

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