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LL 24: Passive Cooling

AIVC, 2001
AIVC | LL
Bibliographic info: LL 24
Languages: English

Passive Cooling


#NO 11441 An annotated bibliography: passive cooling technology for office buildings.

Limb M J

UK, Air Infiltration and Ventilation Centre, May 1998, 39pp.

Gives an overview of current developments into passive ventilation technologies within office buildings and their impact on current ventilation practices. Covers prevention of heat gains, modulation of heat gains, and heat dissipation.

passive cooling, office building

#NO 11442 Using fabric thermal storage to provide passive cooling.

Ogden R, Kendrick C

UK, Building Services Journal, May 1998, pp 47-48, 2 figs.

Describes how studies at the Oxford Brookes University have shown that opportunities for improving a building's fabric thermal storage performance relate more to aspects of its configuration, control and ventilation strategy than the choice of structural system.

thermal mass, passive cooling, ventilation strategy

#NO 11443 A parametric study of Trombe walls for passive cooling of buildings.

Gan G

UK, Energy and Buildings, No 27, 1998, pp 37-43, 8 figs, 1 tab, 21 refs.

Air movement in a naturally-ventilated room can be induced through the use of a solar chimney or Trombe wall. In this work Trombe walls were studied for summer cooling of buildings. Ventilation rates resulting from natural cooling were predicted using the CFD (computational fluid dynamics) technique. The renormalisation group (RNG) k-epsilon turbulence model was used for the prediction of buoyant air flow and flow rate in enclosures with Trombe wall geometries. The CFD program was validated against experimental data from the literature and very good agreement between the prediction and measurement was achieved. The predicted ventilation rate increased with the wall temperature and heat gain. The effects of the distance between the wall and glazing, wall height, glazing type and wall insulation were also investigated. It was shown that in order to maximise the ventilation rate, the interior surface of a Trombe wall should be insulated for summer cooling. This would also prevent undesirable overheating of room air due to convection and radiation heat transfer from the wall.

passive cooling, solar chimney, computational fluid dynamics, ventilation rate

#NO 11475 Passive evaporative cooling: the PDEC project.

Galata A, Sciuto S

Morocco, Marrakesh, ITEEC 1997, proceedings of ITEEC 97 International Thermal Energy and Environment Congress, held 9-12 June 1997, Marrakesh, Morocco, pp 832-836, 4 figs, 6 refs.

The growing use of conventional HVAC systems in offices and commercial buildings in Southern Europe is having a major impact on electricity demand. Passive Downdraught Evaporative Cooling (PDEC) techniques offer significant potential for reducing the energy demands for cooling of non-domestic buildings in hot dry climatic regions. Air can be delivered by capturing the wind within a tower, and cooling may be achieved by spraying microscopic droplets into the airstream. With PDEC cooling process, the air temperature may be reduced by 70-80% of the wet-bulb temperature depression, providing the potential for very significant cooling in hot dry climatic regions. While the potential of this technique has been already demonstrated, the cooling capability and indoor comfort have yet to be assessed, to promote a wider application to non-domestic buildings. To investigate the PDEC system, a three year research is being performed by a multi-disciplinary European Consortium, in the frame of the European Commission JOULE II programme. This paper will illustrate the PDEC Experimental Test Facility, and the experimental measurement campaign to inquire on the cooling capability and indoor comfort.

passive cooling

 


#NO 11482 Ventilative Strategies for Low-Income Dwellings

Mosconi P, Elicabe Urriol J, Di Bernardo E

Sweden, Stockholm, KTH Building Services Engineering, 1998, proceedings of Roomvent 98: 6th International Conference on Air Distribution in Rooms, held June 14-17 1998 in Stockholm, Sweden, edited by Elisabeth Mundt and Tor-Goran Malmstrom, Volume 1, pp 37-44.

Passive cooling devices for low-cost housing, where thermal comfort is usually not considered as an important variable of the design process are evaluated. Low-cost dwellings, located in Rosario city, Argentina, with temperate-humid climate are presented. Their design is the result of the interaction of occupants' participation and experts' advice. Passive cooling systems' efficiency for this climate is very low, due to the combination of high air temperatures and vapour pressure, which reduce convective cooling efficiency. An alternative to ameliorate summer conditions could be to enhance airflow patterns through natural ventilation. A sequence of diurnal and nocturnal ventilative strategies is proposed to achieve thermal comfort. Two ventilative systems have been installed: a duct located at the ridge of a pitched roof and an underground air-heat exchanger buried at depth foundations. Both are to operate depending on climate conditions. Results of systems performance are compared with theoretical considerations.

low income housing, ventilation strategy, passive cooling

#NO 11813 Precise services.

Bunn R

UK, Building Services Journal, November 1998, pp 20-24, 3 refs.

Describes the new headquarters of precision instrument manufacturer Oxford Instruments, which is a mixed mode building, incorporating shallow-plan floors, mixed-mode ventilation, openable windows and high daylight factors. There is underfloor mechanical ventilation with heat recovery, stack-assisted natural ventilation via the atrium. A borehole has also been sunk for future use as a passive cooling device.

low energy building, office building, mixed mode ventilation

#NO 11825 European studies on natural ventilation.

Limam K, Allard F, Dascalaki E, Abadie M

EDSEEB 98, pp 20-25, 5 figs, 1 tab, 12 refs.

This article is aimed at architects, policy makers and engineers who need to acquire a broad background knowledge about natural ventilation. Natural ventilation offers robust solution capable of providing acceptable indoor air quality and comfort throughout the full range of climate conditions. Most projects use natural ventilation as the principal technique for passive cooling and to provide an acceptable indoor environment. In most cases the minimum ventilation rates needed for indoor air quality can easily be reached, and the maximum ventilation rates needed for summer thermal control of the building can readily be identified. While natural ventilation is very attractive, good design of naturally ventilated buildings needs to take into account many phenomena and criteria which are not necessarily easy to handle. Describes research done in Europe within the frame of the PASCOOL and AIOLOS projects which has included experimental and modelling work intended to fill existing gaps in our knowledge of indoor air conditions in naturally ventilated buildings. States that the projects have pointed out critical barriers to the effective use of technical solutions and the difficulties in designing and dimensioning efficient systems for natural ventilation.

natural ventilation, research projects

#NO 11828 Environmentally friendly cities. Proceedings of PLEA 98 Passive and Low Energy Architecture, 1998.

Maldonado E, Yannas S (Eds.)

UK, James & James Ltd, 1988, proceedings of PLEA 98 conference, held Lisbon, Portugal, June 1998, 691 pp.

Universal expositions are opportunities to create something unique and innovative in terms of town planning, and in formal terms, they mark the urban development of the cities where they are held.

The holding of the 1998 World Exposition - EXPO'98 - in Lisbon, is accompanied by the urban renewal of the Redevelopment Area (RA), where the Exposition will not be a short-lived ephemeral event standing outside urban concepts, objectives and strategies, but rather an act of "city-building".

EXPO'98 is thus an opportunity not only to improve and renew the city in urban and environmental terms, but also to modernise and internationalise the city of Lisbon.

Environmental valorisation is part of the overall objective of the Urban Plan (UP) and has been taken into account throughout the definition of planning concepts and strategies. Environmentally relevant factors were the subject of specific studies, which were then taken as the basis for the plans and projects developed.

The urban planning stage had to provide a support framework and ensure the harmonious integration of the many contributions, responding to the challenge of implementing urban and environmental renewal within the concepts as expressed. Now that the World Exposition will definitely be held in accordance with the proposed urban development, it is universally acknowledged that the urban planning process is a guarantee of the environmental and energy sustainability desired by everyone.

low energy building, passive solar building, urban planning, bioclimatic design, retrofitting, daylighting, passive cooling, natural ventilation, building materials, design tools

#NO 11833 An environmentally conscious house for Tamare, Venezuela. An architectural proposal for warm humid climates.

la Roche P, Mustieles F, Machado M V, et al

UK, James & James Ltd, 1988, proceedings of "Environmentally friendly cities", PLEA 98 (Passive and Low Energy Architecture) conference, held Lisbon, Portugal, June 1998, pp 253-256, 9 rigs, 2 refs.

A bioclimatic house for Tamare, Venezuela, designed to provide psychological, physical and social well being through improved comfort and less energy consumption is explained. Digital and analog models were built to analyze sunlight and shadow behavior and computer simulations to predict thermal performance. Assuming a maximum comfort temperature of 30 Deg.C we achieved 95% of satisfaction when we ventilated at night and closed the building during daytime. Some bioclimatic principles integrated in the design are: 1) minimization of solar radiation gains through windows, using solar protection and exterior building facades to generate shadows 2) minimization of conduction heat flow and thermal amplitude by adequate positioning of mass and insulation 3) control of airflow through windows, and 4) use of vegetation to diminish surrounding air temperature. Some passive cooling techniques are: 1) comfort ventilation and 2) nocturnal convective cooling. Mechanical cooling can also be used in combination with passive cooling principles. Construction of the Tamare house will begin in mid 1998 with funding from PDV, the national oil company. Indoor thermal and air quality parameters will be monitored after construction to evaluate its performance.

humid climate, thermal performance, nighttime ventilation, cooling, landscaping, passive cooling

#NO 11834 Passive control of architectural environment based on the design method of Korean traditional architecture with reference to "Young-am House".

Kyung Hoi Lee, Tong So Park, et al

UK, James & James Ltd, 1988, proceedings of "Environmentally friendly cities", PLEA 98 (Passive and Low Energy Architecture) conference, held Lisbon, Portugal, June 1998, pp 257-260, 4 figs, 8 refs.

The examination of the "Young-am House", a traditional folk house located in the middle region of the Korean peninsula, aims to analyze and to inform the bio-climatic design of the building and interior spaces based in the traditional architecture of Korea. As a consequence of the examination, it was evident that bio-climatic design performed an important part in creating a natural environment for comfortable living by taking consideration of the changing local climatic conditions. In the case of the "Young-am House", it is remarkable to see how efficiently the comfort requirements are met comprehensively through the design of the building by incorporating passive measures with a direct effect, such as passive heating and cooling, shading, natural ventilation, etc. Changes of temperature and thermal zones were taken into consideration in the planning of the functional layout of the plan and sections. Also 

the skin's function in permeability and transparency is capable of being controlled and modified to react accordingly to the changing local climatic conditions.

low income housing, shading, passive cooling, passive heating

#NO 11840 Bioclimatic design strategies in temperate climate. Consistency of passive cooling and heating.

Kodama Y

UK, James & James Ltd, 1988, proceedings of "Environmentally friendly cities", PLEA 98 (Passive and Low Energy Architecture) conference, held Lisbon, Portugal, June 1998, pp 317-320, 6 refs.

In the temperate climate, the consistency of bioclimatic designs for heating and cooling is essential. However, the traditional Japanese houses which have excellent cooling techniques often disclose their poor thermal performance in the winter time. Since long it has been said that they sacrificed the heating performance in return for the cooling performance, as a result of their choice in the time when the consistency was technically impossible. This principle is often considered as a kind of critical expression of their aesthetic sense to give characteristic forms onto the traditional architecture in Japan.

Obviously, this principle can not be accepted in the extremely cold region, like Hokkaido and they have been struggling to find their ways of building after they had settled to Hokkaido as frontiers. It is spontaneous that they imported new technologies, such as super-insulating and super-air tightening from the northern countries in the recent time.

On the other hand, these new technologies become popular also in hot climate region of Japan because they are believed to be effective to reduce the cooling load of air-conditioning,. It is obvious that this is a completely different concept from the traditional concept of bioclimatic design in Japan and sometimes clear contradictions can be observed between them because bioclimatic cooling designs are not always to be effective to reduce the air-conditioning load although they can create the natural pleasant indoor climate. It seems very necessary for the integrated design to co-ordinate the contrast between concepts. 

thermal performance, residential building, superinsulation, air tightness, air conditioning

#NO 11847 A novel concept of facade for daylighting and natural cooling.

Neildez A, Thomson A, Durand N, et al

UK, James & James Ltd, 1988, proceedings of "Environmentally friendly cities", PLEA 98 (Passive and Low Energy Architecture) conference, held Lisbon, Portugal, June 1998, pp 385-388, 8 figs, 7 refs.

The role of metallic surfaces is not only to save energy in winter and in summer by separating the inside and the outside. New and inexpensive ways of collecting solar energy for internal heating, new ways of ventilating, heating and cooling through the fabric elements are described. Two very significant prospects are: radiative cooling by metallic surfaces and enhancement of indirect daylighting by optimised ceilings. The subject of the European CURES program is to promote these new technologies by simulating and testing them.

daylighting, passive cooling

#NO 11848 Air flow through louvred windows in small rooms.

Oliveira F, Bittencourt L

UK, James & James Ltd, 1988, proceedings of "Environmentally friendly cities", PLEA 98 (Passive and Low Energy Architecture) conference, held Lisbon, Portugal, June 1998, pp 393-396, 9 figs, 14 refs.

In equatorial warm humid climates, ventilation has been largely adopted as a major strategy for natural passive cooling. In those climates the use of porous elements is common to allow for permanent ventilation as temperature rarely drops below 20 Deg.C. Nevertheless, the performance of many building components has not been thoroughly determined, making it difficult to predict buildings performance as ventilation rates, estimated in most simulation codes are often based on apertures typologies from temperate and cold regions. This paper is the result of an experimental assessment carried out at the Universidade Federal de Alagoas, comparing the airflow velocity inside two identical rooms. The rooms were shaped and sized similar to a typical local bedroom (2.80 x 3.50 m) , having the same window area as inlet and a door as outlet, both placed in the centre of external walls of the test rooms. In one of the rooms the aperture would have a permanently open window, while in the other one there was a window with horizontal slates. Air speed near the windows were measured to obtained the resistance to the airflow produced by horizontal slates (with and without mosquito screens), under different wind speed and directions. Results show that the resistance to the airflow may vary significantly as a function of wind speed and direction. 

air flow, window, warm climate, humid climate, passive cooling

#NO 11849 Climate change and passive cooling in Europe.

Roaf S, Haves P, Orr J

UK, James & James Ltd, 1988, proceedings of "Environmentally friendly cities", PLEA 98 (Passive and Low Energy Architecture) conference, held Lisbon, Portugal, June 1998, pp 463-466, 2 figs, 9 refs.

Climate modellers estimate that global warming will significantly increase summertime temperatures in Southern Europe by 2-3 K by 2030 if greenhouse gas emission rates continue to grow at close to the present rate. The generation of electricity for air-conditioning and mechanical ventilation making an increasing contribution to emissions. Passive and low energy cooling strategies have the potential to reduce these emissions but their effectiveness is very sensitive to climate, and hence to climate change. Maps of mean maximum air temperature in July in Europe are presented for the current epoch and for 2050. Thresholds for the viability of daytime comfort ventilation and nocturnal convective cooling are identified and the regions of Europe for which these systems may no longer be viable are shown. The reasons for the recent rapid growth in air-conditioning use in commercial buildings in temperate climates are addressed and the role of "mixed mode" buildings in countering this trend is discussed.

climate change, passive cooling, human comfort, commercial building

#NO 11850 Using night cooling in a temperate climate.

Nicol F, Robinson P, Kessler M R

UK, James & James Ltd, 1988, proceedings of "Environmentally friendly cities", PLEA 98 (Passive and Low Energy Architecture) conference, held Lisbon, Portugal, June 1998, pp 467-470, 3 figs, 10 refs.

In 1993, the Open University in Milton Keynes, UK, refurbished the open-plan first floor Design Studio in their Publishing Department to use natural ventilation to keep the interior cool. At the same time the third floor, which was not suitable for passive cooling, was fitted with mechanical comfort cooling units and the intermediate floor was not changed. This paper compares the thermal performance of the three floors and discusses the results of a staff-satisfaction survey conducted among the occupants. It shows that despite conditions being cooler on the third floor in the very hottest weather, the passively cooled floor was preferred overall. Lessons can be drawn for the successful use of passive cooling in temperate climates.

night cooling, thermal performance, occupant reaction, passive cooling

#NO 11987 Air, contaminant and heat transport models: integration and application.

Dorer V, Weber A

UK, Energy and Buildings, No 30, 1999, pp 97-104, 11 figs, 9 refs.

Comfort evaluations cover air quality, thermal, visual and acoustic comfort. Today, only few computer programs allow for the integrated evaluation of several or all relevant parameters. Heat transport, ventilation as well as lighting in a room are influenced by each other. Therefore they should be integrally modelled. As part of the IEA-ECBCS Annex 23 'Multizone Airflow Modelling', such a coupling has been realised by integrating the air flow and contaminant transport simulation code of COMIS into the building and systems simulation code TRNSYS. This paper gives a short description of the concept used for the coupling. Then, two application examples typical for a building design study situation are presented, the first being a multi-storey school building which was passively cooled at night due to natural stack airflow. In the second example the facade of the same building was retrofitted with a glazed outer facade. Ventilation as provided by naturally driven shaft ventilation through the facade spaces. For such cases as described in the examples, it may be necessary due to the complex interactions, to study many configurations to find optimum control strategies for the openings and the blinds with respect to overheating risk as well as to air quality. For the upper floors, the risk of overheating and low air quality may be difficult to minimise without extending the shaft above roof level.

multizone air flow modelling, building simulation, passive cooling

#NO 12138 Passive retrofitting of office buildings: the office project.

Santamouris M, Dascalaki E, Koronakis I

EPIC '98, Volume 1, pp 261-266.

OFFICE is a research project partly funded by the CEC dealing with the passive retrofitting of office buildings to improve their energy performance and indoor working conditions. The project is coordinated by the University of Athens with the participation of organisations and research institutes from eight European countries. The aim of the project is to develop global retrofitting strategies, tools and design guidelines in order to promote successful and cost effective implementation of passive solar and energy efficient retrofitting measures to office buildings. Within the frame of the project, ten office buildings located in different climatic zones around Europe are studied extensively. Case studies are carried out for the selected buildings including energy audits and monitoring activities, specific experiments as well as an assessment of the potential of proposed retrofitting scenarios for each building, with regards to the issues of energy conservation and cost effectiveness.

The final deliverables of the project are:

a) Case studies presenting high quality examples of representative retrofitted office buildings in various parts of Europe b) a Rating Methodology classifying office buildings according to their energy consumption, CO2 production and indoor thermal and visual comfort

c) an Atlas describing the technical and economical potential for energy conservation of selected retrofitting scenarios for defined types of office buildings in different climatic zones of Europe

d) Design Guidelines, performance criteria and methodologies for best practice giving credit for renewable energy sources incorporated into office buildings, all presented in the form of a Handbook. Results from the assessment of the potential of various retrofitting scenarios proposed for each case study are included in the Handbook in the form of brochures.

This paper gives an analytical description of the activities carried out within the frame of the project and describes the resulting final deliverables.

retrofitting, office building, passive cooling

#NO 12149 Comparative experimental study of three passive cooling systems in hot and humid climate.

Gonzalez E, Achard P

EPIC '98, Volume 2, pp 391-396, 5 figs, 6 tabs, refs.

This paper presents the experimental results of the comparative study of three Passive Cooling Systems (PCSs) for the natural conditioning of dwellings carried out in Maracaibo, Venezuela. An experimental platform has been built to study the thermal performance of PCS. It includes: two full scale test cells, a meteorological station and an automated data acquisition system. The results are analysed in terms of Indoor Characteristic Temperatures (ICT), Mean Cooling Potential (MCP) and the Cooling Performance Index (CPI) of each PCS. The studied systems have shown MCP values ranging from 14.7 up to 27.8 W/m2; which means a daily cooling energy average between 353 W/m2 and 670 W/m2. It have been also determined CPI values which represent a thermal cooling loads reduction up to 64%. Two PCSs turned to be especially efficient: the first one, where cooling is achieved by nocturnal radiation and indirect evaporation and the other one, where cooling is achieved by continuos indirect evaporation.

passive cooling system, hot climate, humid climate, thermal performance

#NO 12154 Cometres, a simple tool for the improvement of summer comfort in residential buildings.

Collignan B, Millet J R

EPIC '98, Volume 2, pp 485-490, 5 figs.

In summer, it is possible to achieve a satisfactory comfort in residential buildings with purely passive means as thermal inertia, possibility of cross ventilation and solar protection of the external envelope. These parameters have to be taken into account at the earliest stages of building design. Because the maximum cooling power is generally available at night and the maximum temperature occurs in the middle of the day, the calculation tools must take into account in a quite accurate way the non steady state thermal behaviour of the rooms, and the control strategies must compensate this phase displacement, while keeping the indoor climate comfortable during occupancy. We developed, on the basis on a simple RC equivalent network, a thermal dynamic model with a particular attention paid to the impact of the outdoor noise. This model, called COMETres, follows validation procedure of the TC89WG6 of the European Comity of Normalisation (CEN) which works on thermal performance of buildings in summer without mechanical cooling (prEN 13792). This simplified reference calculation method enables to calculate the indoor temperature profile for a reference warm day according to a zoning of metropolitan French territory. Used primarily for new buildings, this tool will be also be a help for retrofitting.

cooling, human comfort, residential building, passive cooling, cross ventilation, shading

#NO 12159 Night ventilation effectiveness in various types of office buildings.

Geros V, Santamouris M, Guarracino G

EPIC '98, Volume 2, pp 534-539, 7 figs, refs.

The present paper investigates the potential of night ventilation techniques when applied to full-scale office buildings, under different structure, design, ventilation, and climatic characteristics. The approach of this study includes the use of both experimental data and theoretical tools in order to determine the impact and the limitations of night ventilation regarding the thermal behaviour of various types of office buildings. Real scale measurements in three buildings under free floating and air conditioning operation have been performed. The cooling potential of night ventilation techniques when applied to buildings, has been experimentally and theoretically studied.

night ventilation, office building, passive cooling, air conditioning, natural ventilation, thermal mass, simulation

#NO 12170 Atlas of natural cooling techniques in southern Europe: application to evaporative cooling systems.

Belarbi R, Allard F

EPIC '98, Volume 3, pp 763-768, 13 figs, refs.

This study is a contribution to European projects Pascool/Joule II and Altener/Sink that deal with the usability of passive cooling systems in Europe. The first phase of this work was to define design methodology in order to evaluate natural cooling potential according to the climatic quantification criteria of the site, the cooling needs of the building, the cooling system performances, and comfort criteria defined by the couple of temperature and relative humidity set points. Numerical simulations have been performed in the second step in order to calculate the Theoretical Evaporative Potential Index, the Net Evaporative Potential Index, the Cooling Need Index and the Natural Cooling Saving Factor. These parameters have been evaluated for different types of evaporative cooling systems (direct and indirect), for different sites in southern Europe, and for various temperature and relative humidity set points. A design methodology of the natural cooling potential which was developed in order to build southern European atlas will be presented in this paper. This atlas locates the applicability zone of the passive cooling techniques and would provide, for building designers, decision making tools during the first steps of building design.

passive cooling, energy conservation

#NO 12173 Numerical simulation of the air cooling by natural ventilation inside the "Maison ronde" of Botta.

Raymond F, Marenne C, Groleau D

EPIC '98, Volume 3, pp 807-812, 6 figs, refs.

The present study applies the N3S CFD code to the air cooling simulation on an "architectural reference object", namely the "Maison Ronde" of Mario Botta. The summer night situation is examined when natural ventilation creates indoor air motion and cools the building structure. The transient behaviour of the walls is represented by a thermal model coupled with the CFD code. The simulation evaluates the unsteady temperatures of the outdoor and indoor air flow together with those of the wall surfaces. Obtained results are analysed according to the architectural specificities of the building in order to identify the key components that play a major role in the efficiency of the passive cooling process.

numerical modelling, natural ventilation, passive cooling

#NO 12183 Solar access, passive cooling and microclimate in the city: the Polis project.

Littlefair P

EPIC '98, Volume 3, pp 983-988, 1 fig, refs.

This paper describes a European project to produce comprehensive design guidance on urban layout to ensure good access to solar gain, daylighting and passive cooling. The project involves:

1. A comprehensive, integrated analysis of all solar and microclimatic aspects of urban layout, including pollution;

2. Development of a major computer based design tool to evaluate solar access and wind patterns within urban configurations in Europe, and simple manual tools to calculate solar access and daylight availability on obstructed sites;

3. Selected case studies, including two major case studies of southern European sites, to test and refine the guidance;

4. Production of an illustrated design guide, papers and presentations communicating the results.

passive cooling, outdoor air, daylight, passive cooling

#NO 12342 EPIC '98 2nd European Conference on Energy Performance and Indoor Climate in Buildings and 3rd International Conference on Indoor Air Quality, Ventilation and Energy Conservation in Buildings. Volume 1.

Guarracino G (ed.)

France, Lyon, Ecole Nationale des Travaux Publics de l'Etat, November 1998, proceedings of conference held 19-21 November 1998, pp 1-362.

Volume 1 contains papers from sessions on: indoor air quality health and safety; building simulation under uncertain boundary conditions; integration of renewables in buildings with specific attention for photovoltaics in buildings; solar control and advanced windows, thermal, visual and acoustical comfort; advance technologies and computer aided control and energy management; standardisation, energy policy and educational aspects; daylighting and energy efficient artificial lighting; thermal comfort and passive cooling; design and simulation tools; and retrofitting.

indoor air quality, health, energy conservation

#NO 12409 Refurbishment of air-conditioned buildings for natural ventilation.

Kendrick C, Martin A, Booth W

UK, Building Services Research and Information Association (BSRIA), Technical Note TN 8/98, 76 pp, 17 figs, 19 tabs, 38 refs.

It has been demonstrated in a number of case study buildings that it is possible to maintain a comfortable environment when refurbishing without resorting to full mechanical ventilation or cooling.

The benefits of natural ventilation include lower running and maintenance costs, possibly less capital outlay, increased useable/lettable area due to reduced number or size of plant rooms, and potential for increased occupant satisfaction by local control over internal environmental conditions. The use of a naturally ventilated solution rather than an air-conditioned one can certainly result in a more robust building, less susceptible to deficiencies in maintenance.

The use of passive strategies applied to a refurbished building requires careful design if the building is to be successful. Selection of the optimum passive measures will enable comfortable indoor conditions to be maintained or enhanced.

This guidance for refurbishing air-conditioned buildings to utilise natural ventilation is aimed at buildings where consideration is being given to the removal of mechanical ventilation and/or mechanical cooling plant. The guidance is also particularly appropriate where conventional naturally ventilated buildings are to be upgraded to incorporate passive cooling techniques. The use of mechanical ventilation as part of a mixed mode solution is not precluded however, as it is the only viable option in some cases.

refurbishment, air conditioning, natural ventilation

#NO 12492 Cooling without air conditioning. The Torrent Research Centre, Ahmedabad, India.

Ford B, Patel N, Zaveri P, Hewitt M

Pergamon, Elsevier Science Ltd, 1998, proceedings of "Renewable Energy: Energy Efficiency, Policy and the Environment", World Renewable Energy Congress V, 20-25 September 1998, Florence, Italy, edited by A A M Sayigh, Volume 1, pp 177-182, 4 figs.

This paper presents results from the first year of monitoring the performance of a laboratory building in the new 14,000m2 Torrent Research Centre in Ahmedabad, India. The capital and running costs of air conditioning of non-domestic buildings in northern India are very substantial, while building costs (compared with northern Europe) are low. A cooling technique which maximises reliance on the building fabric and minimises reliance on mechanical equipment is therefore likely to be cost effective. Passive Downdraught Evaporative Cooling (PDEC) represents such a technique.

At the Torrent Pharmaceuticals Research Centre in Ahmedabad, PDEC is used to service a number of laboratories and offices within the complex. A central open concourse on three levels allows evaporatively cooled air to be introduced to laboratories and offices at each level and exhausted via perimeter stacks. In the first completed laboratory building the PDEC system has now been working for 12 months. Results from the first summer indicate that internal temperatures are 10-15 Deg. C below the peak external air temperature, good air movement is being achieved, and no complaints of discomfort have been received from the staff. The paper describes and illustrates the key features of the building and reports on monitoring undertaken during April-December 1997.

case study, hot climate

#NO 12494 Protection against solar overheating using high aspect ratio opened vertical cavities.

Lorente S, Massias E

Pergamon, Elsevier Science Ltd, 1998, proceedings of "Renewable Energy: Energy Efficiency, Policy and the Environment", World Renewable Energy Congress V, 20-25 September 1998, Florence, Italy, edited by A A M Sayigh, Volume 3, pp 1320-1323, 8 figs, refs.

The authors present the use of high aspect ratio vertical cavities opened on both ends in order to protect housing against solar overheating. They describe a part of their experimental study and show the gain is substantial as soon as one cavity is opened. Heat transfers through the opened cavity are then computed using a fluid mechanics code. The results show a good accuracy with experiments. The authors conclude about the useful purpose of this system for passive refreshment.

passive cooling

#NO 12495 Night time cooling of a room with large internal heat gains.

Harris D J, McLeod J

Pergamon, Elsevier Science Ltd, 1998, proceedings of "Renewable Energy: Energy Efficiency, Policy and the Environment", World Renewable Energy Congress V, 20-25 September 1998, Florence, Italy, edited by A A M Sayigh, Volume 3, pp 1370-1373, 4 figs, 4 refs.

The aim of the investigation was to determine whether mechanically assisted night cooling could cause any useful reduction in the daytime internal temperature of a room with exposed mass walls, and with constant internal heat gains, and whether the effect could also be achieved by using natural ventilation during the night. The results were used to validate simulations using FACET software.

passive cooling, modelling

#NO 12496 Passive cooling performance evaluation using CFD.

Almao N, Rincon J, Gonzalez J, Gonzalez E

Pergamon, Elsevier Science Ltd, 1998, proceedings of "Renewable Energy: Energy Efficiency, Policy and the Environment", World Renewable Energy Congress V, 20-25 September 1998, Florence, Italy, edited by A A M Sayigh, Volume 3, pp 1391-1394, 4 figs, 2 tabs, refs.

A two-dimensional CFD based model named "EVITA" was developed to simulate the transient thermal performance of rectangular building sections. It is based on the finite volume approach, collocated arrangement of variables and a bounded high order treatment of the convective terms. Equations and assumptions are required to evaluate usual solar passive cooling techniques have been included. Numerical results are compared with experimental values showing good agreement.

computational fluid dynamics

#NO 12497 Improving night ventilation into low-rise buildings in hot-arid climates exploring a combined wall-roof solar chimney.

Aboul Naga M M, Abdrabboh S N

Pergamon, Elsevier Science Ltd, 1998, proceedings of "Renewable Energy: Energy Efficiency, Policy and the Environment", World Renewable Energy Congress V, 20-25 September 1998, Florence, Italy, edited by A A M Sayigh, Volume 3, pp 1469-1472, 5 figs, refs.

A theoretical investigation of a combined wall-roof solar chimney to improve nighttime ventilation in buildings is presented. A spreadsheet computer program is used for the parametric study to find out the optimum configuration of the wall-roof chimney. It has been reported that a roof solar chimney alone can induce an air flow rate 0.81 m3/s when the average incident solar radiation is 850 W/m2. The maximum air velocity induced is 1.1 m/s when the 25 Deg. inclined chimney plates are 0.25m apart. The aim of the paper is to predict the induced air flow as a result of the combined effect and to find the best height. The wall chimney height is varied from 1.95-3.45 m to determine the optimum length in relation to the chimney inlet. The results show that air flow is three times more than that of the roof solar chimney alone (0.81 to 2.3 m3/s). The maximum air flow rate of 2.3 m3/s occurs at 3.45m wall height. ACTION Psychometrics software is used to predict the mean cooling load corresponding to the induced ACH. An air change per hour up to 26 could be achieved for a flat volume (321m3). Such ACH could be utilized to improve night ventilation to reduce indoor air temperature and cool low-rise heavy buildings with large diurnal outdoor temperature variations.

hot climate, dry climate, passive cooling

 

#NO 12498 Passive evaporative cooling by means of wind tower for summer comfort in Algeria (Constantine).

Boucham Y

Pergamon, Elsevier Science Ltd, 1998, proceedings of "Renewable Energy: Energy Efficiency, Policy and the Environment", World Renewable Energy Congress V, 20-25 September 1998, Florence, Italy, edited by A A M Sayigh, Volume 3, pp 1563-1566, 4 figs, refs.

Primary energy consumption in Algeria continues to grow, and this is associated with the growth in sale on conventional air conditioning systems. This was a major impact on electricity demand specially for summer cooling purpose for north and south regions of Algeria.

This investigation demonstrates that the combination of passively driven air movement and evaporative cooling through wind tower system can be used with success and fulfil comfort requirements of hotel accommodation under constant climate. 

passive cooling, hot climate

#NO 12502 Solar chimney for promoting cooling ventilation in southern Algeria.

Bouchair A

UK, Building Serv Eng Res Technol, Vol 15, No 2, 1994, pp 81-93, 17 figs, 10 tabs, 14 refs.

In hot climates ventilation can be a useful means of cooling dwellings, if the outside air is cooler than that inside the dwelling. Often, in hot regions the outside air is so hot during the day that cooling by ventilation is of no benefit until the evening when the outside air cools. Ventilation can then be beneficial, and can be promoted by a sun-warmed cavity or 'solar chimney' added to a building on the sunward side. The cavity may be of any material of high thermal capacity. Heat from the sun is stored within the walls and heats the air within. The cavity is closed at the top and bottom by dampers. These, when opened in the evening, allow the buoyant hot air contained within to rise, drawing cooler outside air into the building. This process continues until the stored energy is consumed. The performance of a typical cavity in inducing ventilation into a house is studied experimentally and theoretically. The measurements are made on a full-scale model under steady-state conditions. Cavity width and air inlet area are important parameters in this study. Measurements are made on the temperature and velocity of the air. Observations on air flow patterns in the room and the cavity are made. A dynamic model is developed based on a finite-difference technique, and used to examine the performance of the cavity in various circumstances. The results show that air movement can be produced by a sun-warmed cavity if the dimensions of inlet and cavity width are kept to certain values, and that thermal comfort can be improved.

passive cooling, hot climate

#NO 12509 Airlit pv.

Palmer J

UK, Building Services Journal, September 1999, pp 31.

Describes how the UK BRE (Building Research Establishment) is bringing together the latest thinking in solar control, natural ventilation, daylighting and pv. Its goal is to cut solar and internal gains so that cooling is not required.

photovoltaics, passive cooling

#NO 12520 Airlit-PV - the development of a facade unit to provide daylight and ventilation with integrated photovoltaic power.

Palmer J, Perera E, White M K

UK, London, Chartered Institution of Building Services Engineers (CIBSE), 1999, Proceedings of "Engineering in the 21st century - the changing world", CIBSE National Conference '99, held 4-5 October 1999, Harrogate International Centre, pp 270-277, 4 figs.

A major concern of those wishing to limit the energy use in buildings is the growing trend towards installing air conditioning in new and refurbished buildings. The Airlit-PV project has taken this challenge and has designed a novel facade unit incorporating the latest thinking in solar control, natural ventilation, daylighting and photovoltaic power. By careful design and intelligent control the goal is to reduce the impact of solar and internal gains to such an extent that mechanical cooling is not required to maintain comfort conditions. The project is co-funded by the EU as part of the Joule programme and in the UK by the DETR as part of the Partners in Innovation initiative.

The facade has three main sections: low section is a vent for providing fresh air for comfort cooling in peak daytime conditions and night cooling; the central section a conventional view window openable by the occupants in extreme conditions; the upper section of the unit is a high level window which also acts as a ventilation pathway. Together with these three sections of the unit there are also the following features to aid its performance: a PV panel which is placed above the main view window and acts as a solar protecting light shelf; a trickle ventilator which also incorporates a fan (driven by the PV power) for providing fresh air for comfort cooling and local air movement; internal blinds to both the central and upper windows to provide occupant control of glare. This paper reports on the design approach and the development of the first prototype unit.

photovoltaics, passive cooling

#NO 12727 Thermal storage case study: combined building mass and cooling pond.

Arnold D

USA, ASHRAE Transactions, Winter Meeting 2000, Dallas, 9 pp, 8 figs, refs.

In 1994 a large U.K. credit card company decided to relocate and centralize its offices and operations from a number of city center sites to the outskirts on a green field site. The company decided that the concept for the new building should be "environmentally friendly," i.e., naturally ventilated and cooled by openable windows. However, during initial studies there was concern over whether natural cooling and ventilation alone would be adequate to maintain thermal comfort during hot weather. The design solution was to provide a mix of passive and mechanical systems that could be switched in response to internal conditions and the prevailing weather. The object was to use passive features, i.e., the building thermal mass and storage and cooling effects of a pond, to maintain thermal comfort whenever possible and only switch to mechanical cooling under extreme conditions. The building was occupied progressively during the spring of 1997. The case study covers the period from the initial design concept to the end of the first 18 months of occupation. 

thermal mass, cooling

#NO 12743 Raffrescamento passivo degli edifici. Passive cooling of buildings - sizing and performance of underground air ducts.

Cucumo M, de Rosa A, Ferraro V, Kaliakatsos D

Italy, CDA, No 1, January 2000, pp 31-39, 12 figs, 11 tabs, 12 refs, in Italian.

The cooling of buildings by means of passive systems that do not require the use of air treatment apparatus is dealt with this paper. A suitable ventilation flow is taken from fixed or movable air vents taking advantage of dynamic wind pressure or the prevalence of a fan and transferred to underground ducts where it undergoes cooling and dehumidification. The aim of the paper is the sizing and optimising of the buried ducts with the purpose of obtaining inlet air conditions to rooms that guarantees satisfactory comfort to it's occupants.

cooling, dehumidification, ductwork, thermal comfort

#NO 12744 Natural ventilation studies within the EC PASCOOL Joule II Project.

Allard F, Dascalaki E, Limam K, Santamouris M

UK, Air Infiltration Review, Vol 17, No 4, September 1996, pp 1-4, 1 fig, 1 tab, 12 refs.

Natural ventilation is the first design strategy used by architects or designers to reduce building cooling loads and improve indoor comfort in Mediterranean countries where air conditioning systems do not represent a systematical and realistic alternative. Unfortunately if the effects of natural ventilation on the energy balance of a room or on the perceived comfort of the occupant have been extensively described and can be experienced by anyone, the prediction and design of natural ventilation and its integration in building design as a passive cooling strategy is not really well dominated. In order to fill these existing gaps, natural ventilation phenomena have been extensively studied in the framework of the PASCOOL research project. Describes the aims and strategies of the project, and the final products and main results in terms of single sided ventilation, cross ventilation, and air flow predictions.

natural ventilation, cooling

 

#NO 12879 Cooling effectiveness of south facade passive stacks in a naturally ventilated office building.

Ni Riain C, Kolokotroni M, Davies M, et al

Indoor and Built Environment, No 8, 1999, pp 309-321, 10 figs, 2 tabs, 21 refs.

This paper is based on measured environmental conditions and ventilation rates during a summer period in the occupied naturally ventilated and passively cooled Environmental Building at the Building Research Establishment, Garston, UK. Initially, the comfort and air quality environmental conditions in the first (typical) floor of the building are discussed. These are found to be satisfactory. The paper then goes on to investigate the cooling effectiveness of the various ventilation flow paths and associated thermal mass. In particular, the paper focuses on the south façade passive stacks and their relative contribution to cooling through increased ventilation. It was found that due to the relatively narrow plan of the building, the cross-ventilation flow paths could satisfy most of the summer cooling ventilation requirements. Passive stacks can enhance the cooling ventilation of the space during warm and still days, as intended by the design, and may also have the potential to assist night-time cooling due to their thermally massive structure. 

cooling, passive stack ventilation, case study

#NO 12928 Dynamic thermal sensation in PDEC buildings.

Fiala D, Lomas K J, Martinez D, Cook M J

in: PLEA '99 "Sustaining the Future - Energy, Ecology, Architecture", proceedings of a conference held Brisbane, Australia, September 22-24, 1999, edited by Steven V Szokolay, published by PLEA International, in conjunction with the Department of Architecture, The University of Queensland, Brisbane, Volume 1, pp 243-248, 4 figs, refs.

In buildings with passive downdraught evaporative cooling (PDEC), occupants are subjected to environmental conditions which might be characterised by elevated relative humidities, increased air speeds, and time-varying internal conditions. A new phsiological model which describes the human thermophysiacl system, and the active control exercised on it, has been produced. The model predicts skin and core temperatures, sweet rates, etc. on different parts of a seated, standing or exercising human. It also predicts the overall level of thermal discomfort for any set of time-varying, asymmetric environmental conditions, i.e. the dynamic thermal sensation, DTS. This paper illustrates the application of the model to the design of PDEC spaces. 

evaporative cooling, occupant reaction, modelling

#NO 12936 Passive responses for comfort conditions in a closed atmosphere under hot dry climates.

Bouillot J, Ayoob A N

in: PLEA '99 "Sustaining the Future - Energy, Ecology, Architecture", proceedings of a conference held Brisbane, Australia, September 22-24, 1999, edited by Steven V Szokolay, published by PLEA International, in conjunction with the Department of Architecture, The University of Queensland, Brisbane, Volume 1, pp 393-398, 8 figs, refs.

In many countries, besides the hot dry climate, the lack of energy resources is one of the brakes to the development: without air conditioning, it is not yet possible to give good conditions of working inside offices; air movements, dust, pollution are not consistent with cleanliness, controlled atmosphere and calm air.

Furthermore, sanitary spaces as hospitals and laboratories , and cultural ones as museums and libraries are interested in passive solutions to cooling in a closed atmosphere, ie: without any air movement, except controlled-filtered ventilation.

One solution with two speeds is explored here: the basic one is built up from evaporative cooling, the subsidiary one from air movement; the two work inside the built structure of the building (walls and floors) during the night in hot dry season. 

hot dry climate, evaporative cooling, air movement

#NO 12938 Surabaya eco-house: an experiment in passive design in a tropical climate. Part 1: outline of the project and design of the experimental building.

Kodama Y, Funo S, Hokoi S, et al

in: PLEA '99 "Sustaining the Future - Energy, Ecology, Architecture", proceedings of a conference held Brisbane, Australia, September 22-24, 1999, edited by Steven V Szokolay, published by PLEA International, in conjunction with the Department of Architecture, The University of Queensland, Brisbane, Volume 1, pp 407-412, 9 figs.

Entrusted by the Ministry of Construction, the infrastructure Development Institute Japan conducted an experiment on energy- and resource-saving collective housing jointly with the Institute of Technology Sepuluh Nopember (ITS), the Republic of Indonesia, for the purpose of making contribution to improvement of living environment and energy conservation in developing countries.

In order to build a sustainable and recycling-based society. It is essential to improve performance of buildings themselves in the light of regional climate and to create favorable indoor environment with less dependence on energy-consuming technologies. This requirement must be fulfilled at an early date in developing countries, where energy consumption is expected to rise sharply.

The latest project is a case study designed to build future energy- and resource-saving collective housing in developing countries featured by tropical climate high temperature and humidity 

passive cooling, tropical climate, humidity

#NO 12939 Surabaya eco-house: an experiment on passive design in a tropical climate. Part 2: evaluation and simulation of the effects on thermal performance.

Kodama Y, Funo S, Takemasa K, et al

in: PLEA '99 "Sustaining the Future - Energy, Ecology, Architecture", proceedings of a conference held Brisbane, Australia, September 22-24, 1999, edited by Steven V Szokolay, published by PLEA International, in conjunction with the Department of Architecture, The University of Queensland, Brisbane, Volume 1, pp 413-418, 13 figs, 1 tab.

After the completion of a building, preparatory monitoring was conducted. On the basis of the results, positions and time of observation were changed, and observation modes were determined. In order to verify the effects of the installed passive cooling system and the influence of living styles, operation of a water circulation system was combined with that of openings to determine five modes.

green building design, tropical climate, thermal performance

#NO 12940 The potential of passive cooling strategies for improving ambient comfort conditions and achieving energy savings in a typical hot/arid climate.

Garcia-Chavez J R

in: PLEA '99 "Sustaining the Future - Energy, Ecology, Architecture", proceedings of a conference held Brisbane, Australia, September 22-24, 1999, edited by Steven V Szokolay, published by PLEA International, in conjunction with the Department of Architecture, The University of Queensland, Brisbane, Volume 1, pp 421-426, 2 figs, refs.

Passive cooling strategies can offer significant opportunities for improving the occupants' ambient comfort conditions whilst reducing the energy consumption in hot climates. This is particularly applicable for buildings located in hot/arid regions with large cooling loads due to the use of mechanical systems for space climatization. This research examines the potential of passive cooling strategies in a commercial building located in a typical hot/arid climate of Mexico. The main objective of this work is to achieve maximum human comfort and air quality at minimum capital and operational energy costs, whilst preserving the external environment. The results of this work can contribute to achieve a favorable multiple effect in the country for other buildings with similar conditions and this approach can be useful to provide an authentic sustainable development improving the natural environment and the quality of life. 

passive cooling, human comfort, hot dry climate

#NO 12942 The design and control of buildings with passive downdraught evaporative cooling.

Robinson D, Cook M J, Lomas K J, Bowman N T

in: PLEA '99 "Sustaining the Future - Energy, Ecology, Architecture", proceedings of a conference held Brisbane, Australia, September 22-24, 1999, edited by Steven V Szokolay, published by PLEA International, in conjunction with the Department of Architecture, The University of Queensland, Brisbane, Volume 1, pp 453-458, 5 figs, 1 tab, refs.

This paper describes part of an EC funded Joule project in which computer simulation has been used to investigate the viability of applying passive downdraught evaporative cooling (PDEC) to non-domestic buildings in hot dry climates . using analytical techniques, CFD and thermal simulation, the performance-driven anatomy of PDEC buildings has been elucidated and engineering sizing methods have been developed. It is concluded that PDEC should formulate part of an holistic and carefully integrated solution. Its success is contingent upon the need to obviate wind and for many locations mechanical cooling support should be specified to ensure year-round occupant comfort. Nevertheless, water consumption is sufficiently low and energy savings are sufficiently high to warrant its increased application. 

building design, evaporative cooling, hot dry climate

#NO 12949 Use of a wind wing-wall as a device for low-energy passive comfort cooling in a high-rise tower in the warm-humid tropics.

Jones P J, Yeang K

in: PLEA '99 "Sustaining the Future - Energy, Ecology, Architecture", proceedings of a conference held Brisbane, Australia, September 22-24, 1999, edited by Steven V Szokolay, published by PLEA International, in conjunction with the Department of Architecture, The University of Queensland, Brisbane, Volume 1, pp 501-506, 8 figs, 1 tab.

This paper discusses the use of the 'wind wing wall' as a device for the passive low-energy 'comfort cooling' of the occupants in the interior of a tall building. The case study building is a 2-storey, high-rise office tower, the UMNO building designed by Hamzah and Yeang located in Penang, Malaysia (latitude 5.24 oN) which has been designed to be air-conditioned, but can also be naturally ventilated if conditions are suitable. The paper describes cfd air flow modelling of the wind effects of the building and the effect on internal temperatures, air movement and ventilation. 

passive cooling, high rise building, tropical climate

#NO 12952 PLEA 99 Sustaining the Future: Energy, Ecology, Architecture. Proceedings Volume 1.

Szokolay S S (ed.)

Australia, Brisbane, University of Queensland, Department of Architecture and PLEA International, 1999, proceedings of a conference held 22-24 September 1999, Volume 1, pp 1-520 .

This volume of the proceedings contains sections on sustainable architecture; the ecology of materials; sustainable bioclimatic design and some projects; climate and comfort; houses and housing; tropical architecture; passive cooling.

sustainability, bioclimatic design, building design

#NO 13068 On the impact of the urban environment on the potential of natural ventilation.

Santamouris M, Dascalaki E, Klitsikas N, Papakonstantinou K, Georgakis C

UK, Air Infiltration and Ventilation Centre, proceedings of "Innovations in Ventilation Technology", 21st AIVC Annual Conference, held The Hague, Netherlands, 26-29 September 2000, paper 19.

Knowledge and estimation of the wind speed and air flow characteristics, in a city, is of vital importance for passive cooling applications and especially in the design of naturally ventilated buildings. This study refers to the analysis of the wind characteristics in urban canyons as a function of the free stream wind. The impact on the airflow rate calculation is discussed for an urban canyon. The aim of this study is to get a better insight into the impact of the urban environment on ventilation effectiveness. For this reason, a large number of data are collected including air temperature, wind speed and direction above and at various heights inside ten urban canyons in Athens. Two ventilation techniques are considered: single sided and cross ventilation. Three different cases are studied regarding the incidence angle of the free stream wind to the canyon axis: (a) vertical incidence, (b) parallel incidence and (c) oblique wind. Finally a model is proposed for the simple calculation of the wind speed and air flow characteristics in urban canyons.

natural ventilation, wind speed, urban environment, outdoor air, passive cooling

#NO 13159 Making ventilation work for cooling.

Liddament M W

UK, Pergamon, 2000, proceeding of "Renewable Energy. Renewables: The Energy for the 21st Century. World Renewable Energy Congress VI", edited by A A M Sayigh, held 1-7 July 2000, Brighton, UK, Part 1, pp 420-425, 2 figs, refs.

Night ventilation can meet the cooling needs of many buildings in mild to moderate climates. To be successful, good contact with the thermal mass of the building is needed and a control strategy is necessary to ensure that night ventilation takes place without over cooling the structure. The approach must also be combined with other measures including solar shading and minimizing internal heat sources. Recent case studies from a number of research programmes have demonstrated successful field results. The purpose of this paper is to review some of these studies and highlight the performance and range of applicability of this cooling strategy. Results show that this approach is applicable to the climates similar to that of much of middle to Northern Europe. Performance, however, is subject to a well designed ventilation strategy ( providing between 6-10 ach at night), exposed interior thermal mass, external shading from solar radiation and internal heat gains of no more than approximately 30 W/m2 of floor area. 

cooling, natural ventilation, night cooling, passive cooling, case studies

#NO 13160 Wind towers and wind driven ventilation.

Battle G S, Zanchetta M, Heath P

UK, Pergamon, 2000, proceeding of "Renewable Energy. Renewables: The Energy for the 21st Century. World Renewable Energy Congress VI", edited by A A M Sayigh, held 1-7 July 2000, Brighton, UK, Part 1, pp 432-437, 4 figs, ref.

Passive cooling techniques driven purely by natural wind forces presents a highly attractive environment solution in the perspective of low energy architecture. The physics governing passive cooling are well understood and have been extensively discussed in the literature. Indeed the necessary design details that must be incorporated to achieve the full potential of the technique, such as exposed thermal massive that good internal and solar gain control, are also well understood. Furthermore, the mechanisms by which occupant comfort is achieved can be quantified allowing various designs to be literate towards the optimum solution.

However, issues concerning the design and sizing of apertures for ingress and egress of the ventilation air are less clear, and in particular, there are few "engineering" methods available to size wind towers and wind scoops. The present paper discusses the wind tower calculation method, developed by Battle McCarthy, in conjunction with Imperial College. The calculation method, derived from extensive wind testing provides the designer with an accurate engineering tool for determining the size and number of wind towers and scoops for use in natural ventilation. 

wind effects, passive cooling, low energy architecture

#NO 13164 Parametric sensibility study of an indirect evaporation passive cooling system in hot and humid climate.

Almao N, Dopazo J, Rincon J, Gonzalez E

UK, Pergamon, 2000, proceeding of "Renewable Energy. Renewables: The Energy for the 21st Century. World Renewable Energy Congress VI", edited by A A M Sayigh, held 1-7 July 2000, Brighton, UK, Part 1, pp 516-519, 4 figs, refs.

A numeric parametric study of an indirect evaporation passive cooling system (IEPCS) to obtain the design characteristics that will guarantee its best performance under hot and humid climate conditions is presented. This IEPCS will be part if a bioclimatic house prototype to be built in Maracaibo, Venezuela. Water thickness and air velocity over the water were selected as parameters affecting the system performance. Numerical simulations have been carried out using a two-dimensional CFD code.

passive cooling, hot climate, humid climate

#NO 13185 Predicted comfort envelopes for office buildings with passive down draught evaporative cooling.

Martinez D, Fiala D, Cook M J, Lomas K J

UK, Oxford, Elsevier, 2000, proceedings of Roomvent 2000, "Air Distribution in Rooms: Ventilation for Health and Sustainable Environment", held 9-12 July 2000, Reading, UK, Volume 1, pp 53-58, 3 figs, refs.

Passive Downdraught Evaporative Cooling is a low energy strategy for maintaining thermal comfort in buildings located in hot dry climates. The thermal performance of such buildings can be predicted using simulation models. The temperatures predicted can be compared with standard comfort envelopes which show the range of temperatures and relative humidities within which occupants will be thermally comfortable. Standard comfort envelopes do not account for the adaptive opportunity which is important in free-floating buildings. Such adaptation could include changing clothing levels, local airspeed (e.g. by using of fans) and solar radiation (by use of shading devices). A state of the art dynamic heat transfer and thermal comfort simulation model has been used to develop new comfort envelopes based on the adaptive behaviour theory. These "adaptive comfort envelopes" indicate occupants will be satisfied over a wider range of environmental conditions. The work indicates that increasing local airspeeds is particularly effective in improving comfort when occupants are exposed to solar radiation.

office building, comfort envelope, adaptive behaviour, thermal sensation, PDEC, low energy buildings


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