Category Archives: EuroSun2008-4

Building energy demand

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The specific heating demand of the investigated building was determined to be 12.3 kWh/m2a. This value proves the building to be designed according to passive house standard. Due to high internal loads and large glazing areas, a cooling demand was expected even for a location in central Germany. However, due to the external shading devices used, the simulated cooling demand of the whole building (not considering the server room) was determined to be 1.9 kWh/m2a. In opposite to this relatively low average value over the year, the maximum cooling load of the building was determined to be larger than 30 kW at peak times.

Fig. 3: Energy balance of the building (without server room).

Winter measurements

Concerning the external conditions the monitoring periods that presented lower temperatures during more time were the ones corresponding to the measurements made in housing units1a, 2, 4,

5 and 9, during approximately 5% of the time the temperatures were below 5°C and in approximately 30%-40% of the time the temperatures were between 5°C and 10°C. The other periods had temperatures between 5°C and 10°C approximately 20%-25% of the time.

All the different monitoring, the exterior temperature was most of the time between 10°C and 15°C, near or than 50% of the time. The corresponding measurement periods in the housing units 7, 8, 10 and 11 were the ones to show temperatures between 10°C and 15°C during comparatively more time than the others, approximately 65% of the time. For the different monitoring periods the temperature was between 15°C and 20°C in approximately 10%-20% of the time. Only the measurements in housing units1b, 8 and 11b resulted in exterior temperatures between 20°C and 25°C.

None of the compartments monitored during the 2007-2008 winter months presented interior temperatures below 15°C. However, some had temperatures below 18°C. The only apartment with glazing areas practically to the south that had temperatures below 18°C was dwelling 9 (7%-20% of the time), because it was closed and unoccupied during some time (windows closed and blinds lowered). The other housing units that had temperatures below 18°C were dwelling 8 (west) in 16%-26%of the time, and dwelling 5 (east) in 0,5%-4% of the time.

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The compartments of the housing units with glazing areas oriented practically west and east were the ones that presented interior temperatures between 18°Cand 20°C during more time, approximately between 55% and 70% of the time. Only some compartments with glazing areas practically to the south presented temperatures between 18°C and 20°C, these were housing unitsla, 3, 9 and 11a, in 6% to 26% of the time. The compartment of dwelling 1 with glassed area to the north, presented temperatures between 18°C and 20°C in 32%-52% of the time.

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It was the dwellings with glazing areas oriented to the south, SSE and SSW that presented the temperatures between 20°C and 25°C for more time, on the average 85% of time; while the west presented between 4% and 45% of the time. In some compartments with glazing areas practically to the south (S, SSE, SSW) temperatures above 25°C were obtained even in the cold season; these were housing units: 1 (11%-14% of the time), 2 (10%-27% of the time), 4 and 11 (1-1,5% of the time).

Mean of the mean temperatures: The average of the exterior average temperatures was 11,5°C during the different monitoring periods, while the average of the interior average temperatures in the different monitored compartments was approximately 21°C. For the compartments with glazing areas practically to the south, the average of the average temperatures was approximately 22°C, while for the compartments with glazing areas practically to the east and west was approximately 19,8°C.

Mean of the maximum temperatures: The average of the maximum exterior temperatures was approximately 15°C during the different monitoring periods. For the compartments with glazing areas practically to the south the average of the maximum temperatures was approximately 23°C, being that for dwelling 1 was approximately 25°C and for dwelling 2 25°C-27°C. Some housing units presented an average of the maximum temperature below or very close to 20°C, these were mainly the compartments with glazing areas oriented to the west, east and north. In dwelling 1, while a living room compartment (facade S +E) presented an average of the maximum temperature

of 25°C, the bedroom (facade north) presented an average of 20°C. When comparing dwelling 2 with 5 (similar exterior conditions and average of the maximum temperatures), dwelling 2 presented an average of the maximum temperatures higher than dwelling 5 of 4°C -5°C.

Подпись: Fig.11. Thermal amplitude for the different compartments - winter 2007-2008.

Mean of the minimum temperatures: The average of the exterior minimum temperatures was 8-9°C in the different monitoring periods. Most of the studied compartments with glazing areas practically to the south presented an average of the minimum temperatures greater than 20°C (in general close to 21°C), the west and east housing units had averages lower than 19°C. In dwelling 1, the living room had an average of the minimum temperature of 22°C, while the bedroom 19,7°C.

The exterior thermal amplitude practically varied between 13°C and 18°C in the different monitoring periods. The largest interior thermal amplitude was obtained in the measurements performed in housing units 8 and 11, while the lowest was obtained during the measurements in dwelling 7. The largest interior thermal amplitudes were obtained during the measurements in the compartments with glazing areas oriented practically to the south, amplitudes varying between 5°C and 11°C. Only dwelling 4 had amplitude of 2,5°C, and this due to a heating system type (programmed to maintain temperature of 22 ° C). In the remaining monitored compartments (with glazing areas practically to the east, west and north) the thermal amplitudes were between 3°C e 4,5°C.

3. Conclusions

This paper shows the results obtained in a group of building apartments block during a monitoring campaign (2007-2008), in summer and winter, in order to study the internal thermal comfort in building with similar characteristics (high percentage of glazing area 75% of facade area), that have been recently built in Lisbon. The results shows for summer period that all dwellings presented mean temperature above 25°C, close to 80% — 90% of the time the housing units that have large south facing glazing areas reached temperatures above 27°C. In winter monitoring period the registered mean temperatures was 21°C. It was also verified that: the apartments with large south facing glazing areas has temperatures above 23°C, and on certain occasions even reach 28°C. The fractions with large east and west facing glazing areas showed mean temperatures normally between 19°C and 21°C (the minimum temperature observed was equal to 17°C). These very high temperature values in winter can be explained by the existence large glazing areas and the adaptation of high insulated levels for the opaque envelope. With the inquiry distributed among the occupants it was possible to confirm that the conventional heating systems were switched on often. The results shows also that in most of the apartments are uncomfortable conditions in both summer and winter seasons if for comfort temperature are considered 25°C and 20°C, respectively. In these kinds of buildings it is necessary to take much care with the glazing areas and solar protection. The relative humidity was normally between 35% and 65% in the monitored housing units for both seasons.

— Portugal /

References

H. Gonsalves, M. Panao, S. Camelo, A. Ramalho, J. M. Graga, R. Aguiar, (2004). Ambiente Construido, Clima Urbano, Utilizagao racional de energia nos Edificios da Cidade de Lisboa, Lisbon.

H. Gongalves, A. Ramalho, R. Silva, C. Rodrigues, (2006). Comportamento Termico do Edificio Solar XXI — Primeiros Resultados, Lisbon.

H. Gongalves, A. Ramalho, (2006). Comportamento Termico de uma Vivenda Solar Passiva — Casas em Janas Sintra, Lisbon.

Modeling environment

The solutions of adequate solar protections in terms of visual comfort were determined by using Energy Plus, Daysim and Google Sketchup. Several reasons can explain this choice:

Подпись: The simulations were run by using hourly TMY weather data files. Figure 1: Modeling environment and given outputs : Daylight autonomy ( Daysim), lighting index and solar radiation through the room (Energy Plus)

The 3D modeller Google Sketchup is now widely used as a design tool of reference internationally [7]. Besides, the intuitive handling is very easy and allows to quickly model a whole building ;Energy Plus is a widely used thermal simulation programme as well [8].. More recently an Energy Plus plugin has been developed for Sktechup by the DOE. The plugin allows to run Energy Plus simulation from Sketchup. DAYSIM is a daylighting analysis software that calculates the annual daylight availability in arbitrary buildings as well as the lighting energy use of automated lighting controls. Also, Daysim can be called once the building has been described under Sketchup [9].

Cooling system

Some of the installations projected will also be used for the cooling system of the building.

• Upper air grilles.

• During night hours, use of grilles to collect cool air flow generated at an artificial lake located in front of the South facade.

• Absorption engine, supplied by solar thermal panels and a biomass boiler.

• Automatic natural ventilation support at nights.

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Fig.6 Working scheme of the absorption cooling engine

 

The absorption cooling system, together with the solar thermal panels, provides a high efficiency since the greater the energy demand for cooling is, the higher will also solar radiation be. This will make the photovoltaic panels work at maximum capacity.

2.2. Installations

An installation for the management of water is also projected. For this purpose, the following actions are considered:

• Collection of rainwater and storage in an artificial lake.

• Use of water for cooling of air and radiating floor.

• Recycling of wastewater for WC and for garden irrigation.

Moreover, all the systems are designed to be fully integrated and monitored by a control unit, so that a global quantification of systems and resources can be carried out at any moment. The main actions regarding this are:

• Lighting control.

• Temperature control for the solar collection system, the photovoltaic installation, the biomass boiler and the adsorption engine.

• Control of the photovoltaic installation connection to the electricity grid.

• Control of blinds at night.

• Control of blind slats according to solar radiation.

• Control of the natural cooling system at night.

• Control of the heating of common use rooms with the air from the chambers between the photovoltaic panels and the facade of the building.

3. Conclusion

The aim of the construction of a building with these particular features is to put in practice the most innovative technologies in order to minimise the energy demand. The basic line of work is the detailed analysis of all equipment, as well as the focusing on the thermal insulation of the building so that energy supply — always from renewable sources — is reduced as much as possible.

Following the principles of sustainable construction, the project described in the present communication is intended to show that renewable energy technologies can be satisfactorily integrated in construction, with similar efficiency to conventional ones. It is also relevant to note that important economic savings and high profitability will be achieved during the life of the building.

The PETER building is projected to work as a laboratory that will allow the comparison of results obtained in real situations with simulation data generated in the present study. In sum, our efforts are focused towards the industrialisation of construction, and we believe this project to provide an important “know how” reference in such direction.

Acknowledgements

The authors wish to express their gratitude to Program INTERREG III of the European Union — as to the rest of cofinancing institutions — for financial aid for PETER Project. Cooperation among all members of the Project is also acknowledged.

References

[1] Sustenergy. Project financed by Program INTERREG III C. (2007). http://www. sustenergy. com

[2] PSE-ARFRISOL. Bioclimatic architecture and solar cooling. CIEMAT. http://www. energiasrenovables. ciemat. es/suplementos/arfrisol/pse-arfrisol. htm

[3] Contest of ideas: energy efficiency development for rural social housing. Chile. http://www. plataformaarquitectura. cl/2006/09/23/concurso-de-ideas-desarrollo-de-eficiencia-energetica- para-vivienda-social-rural/

[4] Cities for a more sustainable future. Website of the Department of Urban and Landscape Planning in the Superior Technical School of Architecture (Polytechnic University, Madrid) and Housing Ministry. http:// http://habitat. aq. upm. es

[5] Website of the Official College of Architects of Cataluna. http://www. coac. net/mediambient/

[6] Sustainability and construction: (2000) applications and lines of work. Gerona: Department of Architecture and Civil Engineering of the University of Girona. D. L..

[7] F. Cuadros, F. Lopez-Rodriguez, C. Segador, A. Marcos. A simple procedure to size active solar heating schemes for low-energy building design. Energy and Building. 39(2007) 96-104

[8] F. Lopez-Rodriguez, C. Segador, A. Marcos, F, Cuadros. Calculo y comparacion de rendimientos para distintas aplicaciones. Era Solar. 131 (2006). 73-77

[9] Garcia Sanz-Calcedo J., Lopez-Rodriguez F., Cuadros Blazquez F., Moura Joyce A., Energy Management in Health Centres. Energy Conversion and Management. Sent for publication.

PV in the Park

The PV installed in the car park area, as shadow device, has 100 amorphous silicon modules Kaneka GEA60, inst11alled with a 15° tilt, a total peak power of 6.0 kW and an area of 95,0 m2.

The d. c. produced by the PV generator will be converted to a. c. with two inverters SolarStocc PS4000HV, with a nominal power of 3,3 kW. These inverters have a maximum efficiency of 94,4 % and an European efficiency of 93,1 %.

Table 2. Park — PV Modules configuration

Inverter

Modules / string

Nr. of strings

Peak power (W)

1- SolarStocc PS4000HV

5

10

3 000

2- SolarStocc PS4000HV

5

10

3 000

Total

6 000

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Fig. 3. PV Park system configuration.

Air tightness, infiltration and natural ventilation

It is generally recognized that uncontrolled infiltration should be minimized to avoid unwanted heat loss in winter and heat gains in summer. Air tightness standards in construction vary enormously throughout Europe, but legislation is moving towards tight air infiltration rates.

In many climates, Passivhaus require a mechanical supply and exhaust air ventilation system with heat recovery. In this case, excellent airtightness of the building envelope is required. If the envelope is not sufficiently sealed, the airflows will not follow the intended paths, the heat recovery will not work properly, and the energy consumption will rise. In very mild climates, it is possible to build Passivhaus without heat recovery systems. In such a case, if no ventilation system is present, air tightness is not quite as important. Conversely, very airtight buildings without ventilation systems run the risk of bad indoor air quality and excess humidity. Results from this Passive-On project showed that the Passivhaus proposal can also accommodate a less restricted condition in terms of air tightness in particular on milder climates and where traditionally people are used to open windows to refresh and ventilate the spaces.

Natural ventilation can be used very effectively to provide fresh air and improve comfortable and hygienic conditions for occupants. Despite the variability and difficulty to control natural driving forces, natural ventilation can reduce energy consumption, capital and running costs of mechanical and electrical plants as well as the save space for their installation. Also avoiding air conditioning units may reduce health conditions associated with poor maintenance and re-circulation of air.

3.6 Heat recovery systems

A heat recovery ventilator (HRV) can help make mechanical ventilation more cost effective by reclaiming energy from exhaust airflows. HRVs use heat exchangers to heat or cool incoming fresh air, recapturing 60 to 80 percent of the conditioned temperatures that would otherwise be lost. Models that exchange moisture between the two air streams are referred to as Energy Recovery Ventilators (ERVs). ERVs are especially recommended in climates where cooling loads place strong demands on HVAC systems. The heat recovery system is an essential part of the central European Passivhaus, and allows homes to be built without conventional heating systems.

Inner Glazing Temperature

In cold climates such as Canada, perimeter heating is usually required in buildings when the inner glazing temperature falls below 16oC [12], in order to ensure occupant comfort near windows. Fig. 5 shows a comparison of the multi-glazing BIPV systems average monthly inner glazing temperatures for Yellowknife and Montreal. Contrary to configuration A, the inner glazing temperature of assemblies B and C are always close or greater than 16oC in the winter months. In addition, the inner glazing temperature of configuration C is always approximately 1 to 3oC greater than configuration B. Therefore, this particular system could be more beneficial than configuration B in the winter, since it would be possible to maintain occupant comfort with slightly less

perimeter heating. In the summer, however, the inner glazing can reach a temperature close to 24oC and 26oC in Yellowknife and Montreal, respectively. Thus, in Montreal configuration C could result in occupant discomfort.

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Month

 

(b)

 

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Fig. 5 Average monthly inner glazing temperature for Yellowknife (a) and Montreal (b).

Ventilation of spaces through windows

Compared to single-layer wall with openable windows, a double-layer facade enables a different air circulation indoors. An additional layer of glass, which covers the windows, blocks the natural flow of air and reduces the exchange of air between indoors and outdoors. The difference between the air flow through windows situated from the side of prevailing winds and air flow through the window least exposed to the wind is lesser than in the case of traditional window. This circulation is also less affected by the extent of this window’s opening [K. Daniels].

[5] The collector was modeled after the CPC Star azzurro from Ritter GmbH & Co. KG with the following coefficients: po= 0.675, k1=0.697, k2=0.003.

[6] Introduction

The Italian Ministry for the Environment and Ministry of Justice signed a Memorandum of Understanding on November 7th, 2001 for the promotion of solar heating in Italian Jails. The main purpose of the agreement was the installation of up to 5,000 m2 (3.5 MWth) of solar thermal collectors.

Goals of the “Solar Jails” program are to reduce the energy consumption in jails, as buildings owned by public authorities with high and constant annual DHW demand, and to encourage the use of solar heat at large scale. However, besides the environmental and technical aspects addressed, the most challenging purpose of the initiative is the empowerment of the prisoners trained to install and to maintain the plant. In particular, the professional qualification gained on solar are expected afterwards to increase the reemployment opportunities.

[8] Until this moment only two sets of parameters are included in the standard. A set originally from f-chart method [6] applicable to solar pre-heat/solar only systems for hot water preparation and a set for a space heating system of type “direct floor heating” [3]

[9] Presently this area is no longer mandatory but the designer has to prove that, using a “better” collector then a defined reference collector the same Esolar is obtained with a lower collector area then the one obtained with the rule of 1m2/conventional occupant.

[10] Buildings studied

Two typical XVIII century residential buildings of the downtown area of Porto were chosen to be analysed in detail (figure 1). These buildings were undergoing a retrofitting process, already designed after the RCCTE became effective. The study concentrated in the analysis of the retrofitting design and on its compatibility with the regulation and with the conditionings of being at an historical area.

The magnitude of the retrofittings is such that it surpasses 25% of its value, so they must comply with the regulation for new buildings. On the other hand, the regulation foresees that it may not be fully applied in buildings in historical areas if incompatibilities (with the patrimonial values) are found and duly justified. 4 apartments were selected for detailed analysis in building 1, and 2 apartments in building 1.

[11] Suggested surface orientations refer to the northern hemisphere. For southern latitudes readapt the orientation accordingly.

[12] Intervention area and weather

The project is developed at the border of the Chubut plateau, near the pre­cordillera (Figure 4). The weather is the Patagonia Arid Weather Type, characterized by constant winds, low winter temperatures and snows, and strong and periodic aridity conditions.

Figure 4: Geographic situation.

Energy evalution

The energy assessment should be carried out in a quick and simple way by the user of the tool. On the other hand it should consider all properties of the fa? ade influencing the overall energy demand in an adequately accurate manner. This task was solved by a methodological approach in two steps:

Step one is a detailed dynamical thermal simulation for the complete fa? ade variety of the morpholgical box, carried out as a preparatory work within the development of the assessment system. The results are stored by an EXCEL tool.

Step two allows the user of the assessment system to retrieve the energy data of any given fa? ade system via its definition in the morphological box respectively consideration the main six physical properties.

Improvement Of The Thermal Behaviour Of A Public Social Building In Argentina

G. Lesino1*, A. Hernandez1, S. Flores Larsen1, J. W. Ramirez2,

E. Quiles3, G. Lesino1, E. Quiles3, R. Ferioli, A. Gaido

1 INENCO, National University of Salta — CONICET, Avda. Bolivia 5150 — CP 4400 — Salta Capital —

Argentina

2 Social Development Subsecretariat of the General San Martin Town Council 3 SECyT, Science and Technology Secretariat * Corresponding Author, lesino@unsa. edu. ar

Abstract

The transient thermal behaviour of an Integrating Community Center (CIC) to be built in

Villa Zagala, province of Buenos Aires, Argentina, is presented. The building was divided in two independent sectors, (Health and Development) that were simulated for winter and summer. Due to its orientation, the Development Sector is the most uncomfortable both, in winter and summer. The original project was a conventional building designed by the Ministry of Social Development. This project was improved in order to minimize the thermal losses through the building envelope and avoiding overheating in summer through solar control devices. In summer, natural cross ventilation and the use of ceiling fans, and aeolian extractors in the roofs are suggested in order to remove the warm air. The general objective of this study is to spread the application of passive strategies and solar equipment in public buildings of social use, in order to minimize the impacts on the climate and the environment caused by the consumption of conventional energy.

Keywords: bioclimatic architecture, thermal simulation, public buildings, energy efficiency

1. Introduction

This paper presents the transient thermal behaviour of an Integrating Community Center (CIC) to be built in Villa Zagala, province of Buenos Aires, Argentina. The general objective for this project is to spread the application of passive strategies and solar equipment in public buildings of social use, in order to minimize the impacts on the climate and the environment caused by the consumption of conventional energy. The solar improvement of this building is a special project supported by the Energy and Transport Program of the Science and Technology Secretariat (SECyT) for the General San Martin Town Council. The specific aim of the project is the transfer and application of available technological developments related to energy efficiency, renewable energies, building envelope improvement and solar equipment of Integrating Community Centres, with demonstrative and learning purposes. The following subjects will be covered:

a) Installation of solar and special equipment: solar thermal, for sanitary hot water production; photovoltaics, for electric energy generation; and efficient lighting. The photovoltaic system that supplies energy to a part of the emergency light system has didactic and learning purposes.

b) Improvement of the standard envelope of CICs buildings: reduction of the thermal loses through the building envelope (thermal insulation, airtightness, etc.), reduction of cooling loads in summer (overhangs, shading devices, etc.), increase of solar gains in winter and control of warm air flows, improvement of natural and forced ventilation in summer, improvement of daylighting.

c) Training of the Ministry technical staff and of the personal in charge of operation and mainteinance of the equipment in this building and in future buildings where this technology will be used.