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LL 08: Air Infiltration and Ventilation in Commercial Buildings

AIVC, 2001
AIVC | LL
Bibliographic info: LL 08
Languages: English

Air Infiltration and Ventilation in Commercial Buildings


#NO 11217 Why research and development work for retrofitting of commercial and administrative buildings?

Gertis K

Germany, Fraunhofer Institute of Building Physics, proceedings of "Retrofitting in commercial and institutional buildings", an IEA Future Buildings Forum Workshop held in Stuttgart, Germany, April 28-30, 1997, pp 45-52, 5 figs.

Considers the importance of retrofitting in commercial buildings. Emphasises the need for more cooperation between building physics and building services. Considers whether it is a summer or a winter problem (heating or cooling), energy conservation aspects, the improvement of indoor air quality, and the importance of better education, for architects, civil engineers and building services engineers.

retrofitting, commercial building

#NO 11221 Integral planning of commercial buildings.

Diehl J, Willan U, Meyer O

Germany, Fraunhofer Institute of Building Physics, proceedings of "Retrofitting in commercial and institutional buildings", an IEA Future Buildings Forum Workshop held in Stuttgart, Germany, April 28-30, 1997, pp 139-158, 10 figs.

Examines the economical rather than ecological aspects of retrofitting buildings. In fulfilling its economical purpose the relation of price/performance or price/exploitation has to be well balanced, as with any other economical product. This means the total costs, which are the investment costs and the operating costs must be recoverable via the rent within the total time of exploitation. These operating costs, which may be considered as a kind of "second rent" play an ever increasing part. The economical and also ecological target can be reached by Integral Planning, meaning simultaneous collaboration of all parties involved in a construction project., right from the beginning on, when the preliminary design is made. States that a building can be considered to be optimized from the energetical point of view when the annual consumption of energy and other material resources required for technical buildings services plants or systems are minimised in interaction with the overall building performance, while respecting all required criteria for acceptable comfort. Outlines the use of the engineering tool ROM Simulation Software to achieve the target of designing an energetically optimised building under the headings thermal performance simulation, photometric simulation, air conditioning system simulation, air flow simulation, and describes an air flow simulation laboratory operated by the company.

commercial building, retrofitting, simulation

#NO 11230 Air tightness specifications.

Potter I N

UK, Building Services Research and Information Association (BSRIA) Specification 10/98, March 1998, 8pp.

The specifications cover offices, factories and warehouses, cold stores, dwellings, museum and archival storage, and retail stores. The air tightness specifications presented are based on an extensive accumulation of site test data and each specified level has been bettered in practice by a margin of at least 40%. Recommended best practice maximum air leakage in m3.hr-1.m02 at 50 Pa are as follows: Offices naturally ventilated - , air conditioned/low energy 3, factories/warehouses -, superstores 3, museums and archival stores 1.4, cold stores 0.5, dwellings 5. Recommended normal maximum air leakage as follows: offices naturally ventilation 10, air conditioned/low energy 5, factories/warehouses 10, superstores 5, museums and archival stores 2, cold stores 1, dwellings 10.

air tightness, factory, commercial building

#NO 11302 Efficiency based on CFD modelling of extract hoods and diffusers used in HVAC systems.

Smith S J, Gan G, Riffat S B

The Canadian Environment Industry Association (CEIA), 1997, "Ventilation '97: Global Developments in Industrial Ventilation", proceedings of the 5th International Symposium on Ventilation for Contaminant Control, held in Ottawa, Ontario, Canada, September 14-17, 1997, Volume I, pp 205-213, 4 figs, 2 tabs, 12 refs.

Energy use and the environment in mechanically-ventilated industrial and commercial buildings are strongly influenced by the performance of HVAC systems. Accurate prediction of pressure loss enables HVAC systems to be designed to provide maximum efficiency of extraction and contaminant removal. This paper presents the results of an investigation into pressure loss and associated loss coefficient, k-factor, for a number of diffusers and extract hoods. The k-factor can give a direct comparison of performance between different HVAC system components. The results show that the predicted k-factors are on average 20% lower than those currently available in CIBSE and ASHRAE guides. This is in agreement with validated CFD results derived from previous investigations in Smith et al. It will be shown that over estimation of k-factors of individual HVAC system components results in fan oversizing and energy wastage. Therefore CFD can be a useful tool in k-factor prediction and optimising hood design. The results also show a comparison of currently used hood systems with designs that reduce pressure loss and improve extraction efficiency.

computational fluid dynamics, extract hood

#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 11531 Ventilation technologies in urban areas.

AIVC

UK, Air Infiltration and Ventilation Centre, proceedings of 19th Annual Conference, held Oslo, Norway, 28-30 September 1998, 487 pp FOR SALE ONLY PRICE £65.00

Includes sections on modelling and control algorithms, equipment and envelope characteristics, ventilation performance and building airtightness, ventilation strategies and pollutant transport, NATVENT - overcoming technical barriers, and cooling and indoor air quality in commercial and public buildings, 

ventilation system, air leakage

#NO 11536 Modelling supply devices in order to predict improvements in internal air quality. 

Simons M W, Waters J R

UK, Air Infiltration and Ventilation Centre, proceedings of "Ventilation Technologies in Urban Areas", 19th Annual Conference, held Oslo, Norway, 28-30 September 1998, pp 36-46.

The air distribution effects of floor mounted swirl diffusers are investigated and described in this paper. Results are based on a case study of an office typical of those in urban commercial environments. The effects of the swirl applied to the supply air as well as temperature differentials between supply and room air are explored. The investigation is restricted to situations where cooling is required.

The results of the work, which is undertaken by way of CFD analysis, are presented in terms of appropriate ventilation effectiveness parameters. It is observed that variations to the form of swirl devices, changes to temperature differentials and the presence of internal heat sources combine to affect the internal air distribution to such an extent that its nature may vary from displacement to characteristics approaching those of mixing systems. Air quality at head level can change from very good to poor in response to relatively small changes in some of the parameters.

indoor air quality, cooling, computational fluid dynamics

#NO 11549 Controlled natural ventilation for commercial and industrial buildings. 

Knoll B, Phaff J C

UK, Air Infiltration and Ventilation Centre, proceedings of "Ventilation Technologies in Urban Areas", 19th Annual Conference, held Oslo, Norway, 28-30 September 1998, pp 154-167.

The Dutch organization for applied scientific research TNO in Delft developed a system of Controlled Natural Ventilation (CNV). It is produced by the Dutch ventilation firm Braked in Uden. The system controls ventilation grills and windows. Its purpose is: to compensate for fluctuating buoyancy forces (wind and temperature) so that natural ventilation flows are kept on set point value, independent of weather changes and changes in internal heat production; to optimize the air flow distribution over the building to get the highest possible ventilation efficiency; to restrict ventilation openings when draught risks occur. The CNV system is based on a computer program that simulates ventilation. A special inverse version is derived that calculates the optimal ventilation openings for a specific building on each weather condition and for each ventilation set point. The program needs input on local wind effects on the building. They are predicted with another new developed simulation tool, called the 'Cp-Generator'. This special computer program for prediction of wind pressure coefficients (Cp's) is built in as a module in the main program.

Extra features of the CNV system are: rain protection without decrease in flow rate; improved noise reduction; collaboration with mechanical ventilation; anticipation on opening doors; building leakage compensation; adjustment of both flow rate and direction to varying pollution or heat sources; smoother temperature control; special control for smoke ventilation.

building controls

#NO 11744 SITHOK International congress on heating and air conditioning of buildings. Energy and environment. 

Krope J, Novak P (eds.)

Slovenia, Maribor, University of Maribor, 1998, proceedings of Third SITHOK-3 International Congress, May 9-11, 1998, Maribor, Slovenia, 456 pp.

The objective of the Congress was to bring together researchers and practising engineers in the field of heating, ventilating, air conditioning and in the field of energy in the environment. The papers are grouped into five sections: energy, environment and economics; HVAC application in domestic and commercial buildings; HVAC design and computer software; renewable energy sources and transmission systems; general and HVAC system control.

heating, air conditioning

#NO 11762 Sizing and location of passive ventilation openings.

Irving S J, Concannon P J, Dhargalkar H S

UK, ETSU, S/N8/00142/REP, 1995, 37 pp.

Solar driven natural ventilation is becoming an increasingly important strategy for the design of commercial buildings in the UK. Such buildings are becoming increasingly attractive to the market because they offer a combination of reduced environmental impact whilst offering the user an increased facility for individual control. One of the barriers to the further uptake of naturally ventilated buildings is the problem associated with the sizing of natural ventilation openings. Current design methods rely on rather complex computer based design tools which require skill and experience to use effectively. The purpose of this project was to develop some simpler design guidance and/or procedures which would assist the design team to get the fundamentals of the building design right. This requires a method which can be used at the concept design stage. In order to ensure a wide uptake of the results, the method has been developed in parallel with the drafting of the CIBSE Applications Manual on natural ventilation in non-domestic buildings. The project started out with the intention of developing a series of design charts or nomograms which would cover the range of parameters typical of non-domestic building designs in the UK. Initial analysis soon demonstrated that such an approach would be very time consuming, and the results would probably be rather limiting for use in practice. Consequently the project concentrated on developing a design oriented methodology which placed no restrictions on built form or input parameters. This methodology has become known as the "inverse solver". The inverse solver is a method which turns the current approach to design on its head. Rather than seeking to size ventilation openings by an iterative procedure using simulation tools, it establishes a means of calculating opening sizes directly. This means that the method is very fast and direct, and ideally suited to concept design. The methodology has been developed in two forms: a series of worksheets covering the principal design strategies (buoyancy driven and wind driven), and a computerised implementation of the method in a standard spreadsheet. The method has then been "proven" by designing a series of generic buildings using the inverse solver, and then testing the performance of the design by analysing the building performance using an established multi-zone ventilation program. The results showed maximum deviations of about 1% which establishes a high degree of confidence in the method.

commercial building, inlets

#NO 11763 A study of energy use and satisfactory zone ventilation of different outdoor air ventilation strategies for terminal reheat variable air volume systems.

Reddy T A, Liu M, Claridge D E

UK, Energy and Buildings, No 29, 1998, pp 65-75, 9 figs, 5 tabs, 26 refs.

Increased building indoor air quality (IAQ) complaints due to reduced outdoor air ventilation rates led to ASHRAE Standard 62-1989. Even though the stipulated standard total outdoor ventilation flow rate may be drawn into the HVAC system, thermal imbalances in the various zones of the building can lead to certain zones being starved of the specified ventilation flow rate, thereby creating localised IAQ problems. The objective of this paper is to compare the differences in energy use and ventilation air flow rates supplied to different zones in the building for three different practical outdoor air ventilation strategies all of which are identical in performance at design conditions but which differ under part-load operation. A simplified simulation methodology (which past studies have demonstrated to be useful for field evaluation of actual buildings) has been used to predict the heating and cooling energy use of a two-zone terminal reheat variable air volume (TRVAV) system during part-load operation specified by varying outdoor temperature and humidity conditions. The trade-off between outdoor air intake and energy use are studied for the following ventilation strategies for a typical 10,000 m2 commercial building: (i) constant outside air intake based on a value 20% higher than the ASHRAE minimum ventilation rate, (ii) constant ventilation air intake fraction, and (iii) ventilation air intake based on the unfavourable zone requirements (even though the other zone may be over-ventilated). How this trade-off is impacted by building size has also been investigated. Finally, we use bin data for Dallas, TX (a moderately hot and humid location) and Seattle, WA (a mild location) in order to study the differences in energy use and zone ventilation flows of different ventilation strategies due to building location. The effect of economiser cycles and of varying ventilation strategies depending upon diurnal building schedules have not been considered in this study. The results of this study which are based on a simplified HVAC simulation approach are consistent with conclusions reached by other researchers using more detailed simulation models. This suggests that sound and meaningful diagnostic insights of actual building performance and operating strategies can be obtained from such simplified simulations.

ventilation strategy

#NO 11876 Ventilation, humidity, and energy impacts of uncontrolled airflow in a light commercial building.

Withers C R, Cummings J B

USA, ASHRAE, 1998, in: the ASHRAE Transactions CD, proceedings of the 1998 ASHRAE Annual Meeting, held Toronto, Canada, June 1998, 10 pp, 5 figs, 3 tabs, refs.

A small commercial building was monitored before and after energy-saving retrofits to study the impact of retrofits upon ventilation rates, humidity, building pressure, and air-conditioning energy use. Duct airtightness testing identified severe duct leakage as a significant source of uncontrolled airflow. Differential pressure and infiltration measurements using tracer gas indicated an attic exhaust fan as another significant source of uncontrolled airflow. Duct repair results in a 31% drop (30.5 kWh/day) in cooling energy and an increase in relative humidity from 72% to 76%. Turning off the attic exhaust resulted in an additional 36% energy savings (14.3 kWh/day), including fan power, and a decrease in relative humidity from 76% to 58%. Turning off the attic exhaust fan also significantly reduced the ventilation rate in the building by about 62% from pre-retrofit ventilation measurements. The study of this building before and after retrofits illustrates the impacts that air leakage can have on light commercial buildings with nonairtight ceilings, the importance of using good diagnostics to discover all sources of uncontrolled airflow in buildings, and the importance in understanding what the duct zone environment is like in small commercial construction.

humidity, commercial building, retrofitting, ventilation rate

#NO 11877 Building cavities used as ducts: air leakage characteristics and impacts in light commercial buildings.

Cummings J B, Withers C R

USA, ASHRAE, 1998, in: the ASHRAE Transactions CD, proceedings of the 1998 ASHRAE Annual Meeting, held Toronto, Canada, June 1998, 10 pp, 1 fig, 2 tabs, refs.

Field testing in 70 small commercial buildings in central Florida identified that building cavities were used as part of the air distribution system in 33 buildings. The various building cavity types (number of buildings in parentheses) are: enclosed air-handler support platforms (10), mechanical closets (8), mechanical rooms (6), ceiling spaces (7), wall cavities (6), chases (1), and "other" building cavities (2). Testing found that these building cavities are considerably more leaky than standard ducts and plenums because they are generally not built to the same airtightness standard as ducts. Actual air leakage is a function not only of duct hole size but also pressure differential across the leak sites. Pressure differentials generally range from -0.080 in.WC (-20 Pa) to -0.401 in.WC (-100 Pa) in support platforms, mechanical closets and rooms, wall cavities, and chases. By contrast, ceiling plenums often operate at less than 0.004 in.WC (1 Pa) difference from the occupied space and sometimes at positive pressure with respect to outdoors.

The energy, infiltration, and relative humidity impacts of building cavity duct leakage depend upon the leak airflow rate and the temperature and humidity conditions of the air entering the leaks. Therefore, the location of the building cavity ducts is very important. If the return leak air is drawn from the occupied space, that leakage will have little or no impact on energy, infiltration, or relative humidity. At the other extreme, if the leaking air comes from a hot and humid attic space, the impacts will be large. The interaction of various building cavity duct leaks with eight different building configurations - based on the location of the primary air and thermal boundaries in the ceiling space - is discussed here. The paper concludes that building cavities should not, as a general rule, be used as a part of the air-distribution system. The exception is use of ceiling space return plenums. Ceiling plenums can be designed to operate at near neutral pressure with respect to outdoors and, therefore, can experience little or no duct leakage. 

duct, building cavity, air leakage, commercial building

#NO 11891 Placement of ventilation air intakes for improved IAQ.

Rock B A, Moylan K A

USA, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc (ASHRAE), 1999, in: the ASHRAE Transactions CD, proceedings of the 1999 ASHRAE Winter Meeting, held Chicago, USA, January 1999, 9 pp, 5 figs, 1 tab, refs.

ASHRAE Research Project 806, Design Criteria for Building Ventilation Inlets, reviews existing knowledge of the placement of ventilation air louvers, produces a design guide, and suggests additional research, all with the intention of improving indoor air quality in commercial and institutional buildings. Decisions about intake and exhaust placements made early in the architectural and HVAC system design processes will impact occupants over the life of a building. Such placment decisions, therefore, require proper consideration. There is little guidance currently available to designers, but research efforts in this area are expanding.

Previous research efforts and standards relating to ventilation air intake placement are described in this paper. However, more extensive coverage and a lengthy bibliography are provided in the project's "Literature Report". In "A Designer's Guide to Placement of Ventilation Air Intake Louvers" for the project, the phenomena, standards, and design experiences that affect the placement of intake air louvers are reviewed using less technical text, many graphics, and example calculations.

More research is needed on ventilation intake placement for common commercial HVAC systems with rooftop, through-the-wall, and at-grade louvers. Most existing knowledge is derived from the many studies on industrial stack exhaust-gas reentrainment and not common HVAC geometries. The findings of such future research and a summary of this project's "Designer's Guide" need to be included in future revisions of ASHRAE Handbook chapters.

air intakes

#NO 11933 Energy Efficiency in a Competitive Environment. ACEEE Summer study on energy efficiency in buildings. 

ACEEE

USA, American Council for an Energy Efficient Economy (ACEEE), 1998, proceedings of the 1998 ACEEE Summer Study on Energy Efficiency in Buildings, CD format.

The proceedings are divided into sections as follows: residential buildings: technologies, design and performance analysis; program design, implementation and evaluation; commercial buildings: technologies, design and performance analysis; program design, implementation and evaluation; international collaborations and global market issues; deregulation of the utility industry and role of energy services companies; market transformation.

energy efficiency, residential building, commercial building

#NO 11944 Implementation of natural down-draft evaporative cooling devices in commercial buildings: the international experience.

Chalfoun N V

USA, American Council for an Energy Efficient Economy (ACEEE), 1998, in: proceedings of "Energy Efficiency in a Competitive Environment", the 1998 ACEEE Summer Study on Energy Efficiency in Buildings, CD format, pp 3.63-3.72, 6 figs, 1 tab, refs.

Conventional evaporative coolers are high-pressure high volume devices that deliver cool air by water evaporation wetted pads. Natural down-draft evaporative coolers, or "Cool Towers", are devices developed at The University of Arizona's Environmental Research Laboratory. Similar to conventional coolers, these devices are equipped with wetted pads and sprays at the top which provide cool air by evaporation but the air is moved by gravity flow saving the energy required by the blower. In arid regions, cool towers are useful for cooling buildings and outdoor private and public areas. This paper focuses on recent implementation of cool towers in two international projects in arid regions. It also demonstrates CoolT, a software developed by the author, which was used for sizing and designing the cool towers used in these projects. The two demonstrated projects are: 1) The Botswana Technology Centre (BTC), a Headquarters office building in Botswana, South Africa. The building energy loads were first optimized through energy conservation measures where the heating load, as predicted by computer simulation, was reduced by 89.9% and the cooling load by 24%. The cooling load was further addressed by the use of a series of integrated cool towers. 2) The Ministry of Municipal and Rural Affairs (MOMRA) "Environmental Rowdah" Project in Riyadh, Saudi Arabia is the second, recently built project which demonstrates the use of cool towers in outdoor spaces. The Rowdah is equipped with a 76 feet high cool tower, the biggest in the world, which provides cool air to the surrounding outdoor space. The tower performance, as predicted by the CoolT program, demonstrated that on a typical June day in Riyadh, at 3:00 p.m. the ambient air temperature of 107.1 Deg.F (41.7 Deg.C) will be cooled down to 73.9 Deg.F (23.2 Deg.C) i.e. 33.2. Deg.F (18.4 Deg.C) lower, but the 13% relative humidity of air is increased to 75% at the tower discharge.

cooling, commercial building, natural ventilation

#NO 11945 Phase-change wallboard and mechanical night ventilation in commercial buildings: potential for HVAC system downsizing.

Stetiu C, Feustel H E

USA, American Council for an Energy Efficient Economy (ACEEE), 1998, in: proceedings of "Energy Efficiency in a Competitive Environment", the 1998 ACEEE Summer Study on Energy Efficiency in Buildings, CD format, pp 3.317-3.324, 6 figs, refs.

As thermal storage media, phase-change materials (PCMs) such as paraffin, eutectic salts, etc. offer an order-of-magnitude increase in thermal storage capacity, and their discharge is almost isothermal. By embedding PCMs in gypsum board, plaster, or other wall-covering materials, the building structure acquires latent storage properties. Structural elements containing PCMs can store large amounts of energy while maintaining the indoor temperature within a relatively narrow range. As heat storage takes place inside the building where the loads occur, rather than at a central exterior location, the internal loads are removed without the need for additional transport energy. Distributed latent storage can thus be used to reduce the peak power demand of a building, downsize the cooling system, and/or switch to low-energy cooling sources.

We used RADCOOL, a thermal building simulation program based on the finite difference approach, to numerically evaluate the thermal performance of PCM wallboard in an office building environment. We found that the use of PCM wallboard coupled with mechanical night ventilation in office buildings offers the opportunity for system downsizing in climates where the outside air temperature drops below 18 Deg.C at night. In climates where the outside air temperature remains about 18 Deg.C at night, the use of PCM wallboard should be coupled with discharge mechanisms other than mechanical night ventilation with outside air.

mechanical ventilation, commercial building, air conditioning

#NO 11950 Retrofit demonstration in Brazilian commercial and public buildings.

Lamberts R, Thome M, et al

USA, American Council for an Energy Efficient Economy (ACEEE), 1998, in: proceedings of "Energy Efficiency in a Competitive Environment", the 1998 ACEEE Summer Study on Energy Efficiency in Buildings, CD format, pp 5.227-5.238, 12 figs, 3 tabs, refs.

In order to help the development of energy efficiency building standard in Brazil, to demonstrate state of art technologies and to encourage the use of hourly energy simulation tools the National Energy Conservation Program (PROCEL) has started the "6 Cities Project". The project is being developed in six cities around the country. For this project a standard methodology was developed and applied. The methodology consists of a survey in the local utilities to establish the highest energy consumers in the commercial and public sector. A data-base is being created with information on energy consumption intensity and demand intensity in 15 buildings in each city. The data-base was designed to help the standards development. Among those buildings, in each city, two were selected, one is a public building and one a private building, for a detailed energy audit. The audit data was used to calibrate a DOE2 simulation model. Simulations were performed and state of art technologies for energy efficiency are being tested and will be implemented. An after retrofit monitoring program is planned. In this paper the results of the first buildings will be shown.

retrofitting, commercial building, public building, standard, energy simulation

#NO 11975 Understanding and reducing the indoor concentration of submicron particles at a commercial building in Southern California.

Weschler C J, Shields H C, Shah B M

J. Air & Waste Manage. Assoc., Vol 46, 1996, pp 291-299, 7 figs, 16 refs.

Submicron particles play a major role in soiling processes and contribute to corrosion, current leakage and shorts in electronic equipment, For more than a year, optical particle counters have been used to continuously measure the concentrations of submicron particles at a telecommunications facility in Southern California. Separate instruments have simultaneously sampled at four locations; the outdoor air intake, immediately upstream of the HVAC, immediately downstream of the HVAC filters, and inside the office. The indoor concentrations can be explained in the context of a one-compartment mass balance model. Key parameters in the model (e.g., the air exchange rate) were monitored throughout the sampling period. In the latter part of this study, the particle counters were used as feedback elements in the HVAC system. An estimate of the concentration of indoor submicron particles, has been used as a control variable. When this variable exceeds a preset value, the outdoor air damper is partially closed, reducing the amount of outdoor air entering the building. That is, the position of the damper is based on the concentration of outdoor particles as well as the outdoor temperature. As a consequence, the average indoor concentration of submicron particles has been significantly reduced within this facility.

particulates, commercial building, hot climate, filtration

#NO 11976 Indoor chemistry involving O3, NO, and NO2 as evidenced by 14 months of measurements at a site in Southern California.

Weschler C J, Shields H C, Naik D V

Environmental Science & Technology, Vol 28, 1994, pp 2120-21326 figs, 2 tabs, 40 refs.

For more than 1 year, indoor and outdoor O3, NO, NO2 (NOx-NO), temperature, and relative humidity as well as the air exchange rate have been measured continuously at a commercial building in Burbank, CA. The indoor concentration of a given pollutant is a function of its outdoor level, the air exchange rate, the rate at which it is removed by indoor surfaces, and the rate at which it is produced or removed by indoor chemistry. Several examples of indoor chemistry are inferred from daily and seasonal variations in the collected data. These include homogeneous reactions such as those of O3 with both NO (fast) and NO2 (slow) and heterogeneous reactions such as those between NO2 and indoor surfaces. The latter ultimately contribute to indoor levels of both HONO and NO and are more likely to be observed in the absence of indoor O3. Indeed, due to the very rapid )3/NO reaction as well as other slower reactions, the presence or absence of indoor O3 strongly influences speciation among the indoor oxides of nitrogen.

ozone, nitrogen monoxide, nitrogen dioxide, outdoor air pollution

#NO 11998 Myths about building envelopes.

Persily A K

USA, ASHRAE Journal, March 1999, pp 39-47, 5 figs, 3 tabs, 21 refs.

A data set of 139 commercial buildings was assembled from the published literature, and their air leakage values as determined by fan pressurisation testing were examined. No correlation was seen for the hypothesis that newer buildings are more airtight than older buildings. Commercial buildings were not seen to be significantly tighter than US residential buildings. The air leakage data did reveal an impact of building height on airtightness, with the taller buildings being tighter on average and the shorter buildings covering a wide range of airtightness from low to high. 

building envelope, air tightness, air leakage

#NO 12022 Performance of desiccant/evaporative cooling in Canadian office buildings using the functions of DOE-2.1E.

Kemp S, Ben-Abdallah N, Stylianou M, Hosatte S

Canada, CANMET, [1999].

This paper studies and evaluates the performance of desiccant/evaporative cooling systems in a commercial building in Canada from the point of view of comfort for the building occupants using hourly building energy simulation software. The desiccant evaporative cooling system involves a rotary desiccant dehumidification wheel, an indirect evaporative cooler and finally a direct evaporative cooler. The study reveals that under climatic conditions, typical of the region of Ottawa, increased levels of ventilation are necessary when compared to conventional vapour compression system as equivalent supply temperatures (typically 13 Deg. C) are not achievable. The comfort conditions in the building are found to be acceptable when using elevated amounts of supply air. Typically the circulation rate in the building is increased between 150 and 175% from normal direct expansion coil ventilation rates to achieve satisfactory comfort conditions.

cooling, office building

#NO 12231 Particle deposition from turbulent duct flow.

Sippola M R, Nazaroff W W, Thatcher T L

UK, Garston, BRE, 1999, proceedings of Indoor Air 99, the 8th International Conference on Indoor Air Quality and Climate, and the Air Infiltration and Ventilation Centre (AIVC) 20th Annual Conference, held Edinburgh, Scotland, 8-13 August 1999, Volume 2, pp 24-29.

Particle deposition from turbulent duct flow is modelled and related to particle penetration of a ventilation system for a commercial office building. Three published turbulent deposition models capable of accommodating surface roughness are compared to experimental data and used to determine the penetration of 0.1 - 10 (m spherical particles through a sample duct run. Depending on the model employed, penetration fractions varied from 0.40-0.94 for 0.1 (m particles and 0.28-0.73 for 10 (m particles. Penetration is predicted to be independent of particle size for particle diameters less than 2 (m. Almost all the deposition is predicted to occur in short sessions of the duct runs where the wall roughness is larger than in other duct sections because of the duct construction material.

ducts, air flow, particle

#NO 12234 Experimental and numerical investigation on temperature and air velocity distribution in a room equipped with split-system air conditioner.

De Carli M, Peron F, Zecchin R

UK, Garston, BRE, 1999, proceedings of Indoor Air 99, the 8th International Conference on Indoor Air Quality and Climate, and the Air Infiltration and Ventilation Centre (AIVC) 20th Annual Conference, held Edinburgh, Scotland, 8-13 August 1999, Volume 2, pp 42-47.

Spilt-system air conditioning is increasingly used both for residential and commercial applications, owing to its low cost and installation ease. The indoor split-system unit is commonly of the wall-mounted type and, due to its dimensions and position, very often it gives rise to appreciable air velocities and temperature gradients in the occupied zone of the room. This work reports and discusses some experimental data collected in a test room with wall-mounted indoor unit, under different operating conditions. A CFD numerical model has been developed and assessed on the basis of the experimental data; the model can be applied to investigate the influence of different parameters such as air flow and velocity, inlet air temperature, position of the unit, direction of air flow etc. From the results of parametric analyses some conclusions can be drawn, with reference to comfort conditions, useful to improve the design and construction of this type of air conditioning equipment and to develop more efficient installation criteria. 

numerical modelling, air distribution

#NO 12281 Long-term testing of gas adsorption filters for ventilation systems.

Ekberg L E, Strindehag O

UK, Garston, BRE, 1999, proceedings of Indoor Air 99, the 8th International Conference on Indoor Air Quality and Climate, and the Air Infiltration and Ventilation Centre (AIVC) 20th Annual Conference, held Edinburgh, Scotland, 8-13 August 1999, Volume 4, pp 79-80.

A test rig for long-term tests of activated carbon filters was developed consisting of eight parallel test-filter sections. The test-rig was installed on the roof of a six storey commercial building located in the centre of Goteborg, Sweden. By this arrangement, eight activated carbon filters are tested simultaneously under realistic conditions, using the pollutants in the ambient outdoor air as challenge substances.

activated carbon filter

#NO 12336 Retrofitting of heating and cooling systems.

Teekaram A J H, Brown R G

UK, Building Services Research and Information Association (BSRIA), Technical Note TN 15/99, 76 pp.

Aimed to develop assessment techniques that will assist in identifying the most appropriate and economic retrofitting strategy when refurbishing, or enhancing the performance of heating and cooling systems. The guide is intended to be a working document for building professionals. Guidance is provided through a logical sequence of steps starting with consideration of the retrofit options consistent with the client's requirements. Recommendations are made for monitoring of plant performance data, frequency of monitoring, and analyses. The objectives of a site condition survey which forms part of the initial assessment are summarised along with a methodology for performing an option evaluation. The guide is divided into three sections: principles of retrofitting; retrofit options; and retrofitting assessment procedure. Two appendices list information sources and a glossary of terms.

commercial building, retrofitting, design guidance

#NO 12381 Building pressurisation can affect possibility of mould growth.

Anon

USA, IEQ Strategies, August 1999, pp 8-13, 9 figs.

Describes case studies which demonstrate the various ways that forced-air systems can significantly affect building pressures. In each case the authors were contacted to determine the cause of mould growth on interior drywall. In each case also, mould growth was determined to be caused by moisture accumulation in the drywall, primarily from the uncontrolled flow of outside air into the building envelope. The case studies concern: 1. Central exhaust system; 2. Building air chases used as a distribution system; 3. Leakage at guest room fan coil units. Concludes that moisture related damage in commercial buildings can result in millions of dollars in damage annually and can come from five possible sources of moisture: bulk moisture intrusion; internally generated moisture; vapour moisture diffusion; capillarity; air leakage. A primary cause of air leakage is depressurisation of the building by the HVAC system, although many HVAC designs have the opposite intent - to pressurise the building. Unfortunately current HVAC commissioning procedures are unable to accurately determine if the HVAC design intent has been accomplished. This is because current commissioning techniques are based on measurement of airflows at delivery and extraction points, such as a supply registers and exhaust grilles. Airflow measurements at these points alone cannot properly assess the performance of the HVAC system or its impact on the characteristics of a building because they fail to fully consider air distribution. The startup sequence of HVAC forced air systems is also a critical aspect of commissioning a building. An improper startup sequence will prevent a forced air system from performing according to the design intent. If this condition occurs during hot, humid weather, moisture accumulation and mildew can occur within several weeks.

mould, building pressurisation, air flow

#NO 12387 Large-scale glass atrium maximises natural energy.

CADDET

Netherlands, CADDET, Result 338, March 1999, 4 pp.

The Sapporo Factory is a large-scale commercial building complex in the heart of snowy Hokkaido. The complex has a large barrel-roof glass atrium with a comfortable indoor environment, which is maintained by making the most of cool outdoor air in summer and sunshine in winter. The atrium also provides a bright indoor space, which is never covered with snow, even in winter. Any snow falling on the glass roof is removed using the natural characteristics of snowfall. Energy consumption records for the atrium indicate that it is extremely energy efficient due to the effective use of natural energy.

atrium, commercial building, cooling, daylighting

#NO 12388 Solar collector system for heating ventilation air.

CADDET

Netherlands, CADDET, Result 228, January 1996, 4 pp.

The Conserval Perforated Plate Solarwall is a metal solar collector designed to provide preheated ventilation (make-up) air for buildings. The system is intended primarily for industrial applications, but also has potential for commercial and multi-residential buildings with large south facing walls.

In 1991, a 420m2 Solarwall was erected at the General Motors of Canada Battery Plant in Oshawa, Ontario. This installation reduced energy costs in several ways: by capturing solar energy, by reducing heat loss through the south-facing wall of the building, and by destratifying indoor air.

air tightness, solar facade

#NO 12403 Why HVAC commissioning doesn't work in hot, humid climates.

DuBose G, Odom J D, Fairey P

USA, IEQ Strategies, August 1999, pp 4-7.

Moisture-related damage in commercial buildings is a pervasive problem in hot, humid climates. Excess moisture in buildings can stem from failure to control moisture sources, including rain, groundwater, moisture diffusion, and airflows. A growing body of evidence indicates that the most problematic of these climatic moisture sources in hot, humid climates is the uncontrolled flow of outdoor air within the building envelopes. Solving this problem is difficult because current commissioning techniques cannot accurately predict airflows because they do not measure their driving force. As a result, owners cannot identify potential moisture-control problems prior to acceptance of new buildings. Also air -transported moisture is invisible and can travel long distances through interstitial cavities in buildings before accumulating and manifesting in such problems as mould, mildew or corrosion. Thus moisture control problems are not easily diagnosed. The case studies cited in the article illustrate the complexity of the problem and identify common sources of uncontrolled airflows in commercial buildings. 

commissioning, hot climate, humid climate, air flow

#NO 12405 Dual fan and duct ventilation system at Canadian Space Agency.

CADDET

Netherlands, CADDET, Result 285, September 1997, 4 pp.

Canada's space Centre in ST Hubert, Quebec, is a new 27,870m2 complex which was awarded first place in the ASHRAE Technology Awards (1996) for new commercial buildings. A dual duct ventilation system was installed to provide a comfortable and pleasant research environment. Dual duct systems, which are the heart of the mechanical concept, provide high indoor-air quality, along with design flexibility, energy efficiency and low capital costs. During the monitoring period, energy savings amounted to 839,000 kWh/year (electricity) and 275,000m3/year (natural gas), when compared to a conventional system. The payback period is 2 years.

indoor air quality, duct

#NO 12408 Natural ventilation in non-domestic buildings - a guide for designers, developers and owners.

BRE

UK, DETR, Energy Efficiency Best Practice Programme, Good Practice Guide 237, 15 pp.

This guide first summarises the features and benefits of natural ventilation, allowing it to be compared with other strategies including mechanical ventilation and air conditioning. It then considers natural ventilation in the context of the commercial issues that are at the heart of building procurement. Finally, it illustrates the features of naturally ventilated buildings by reviewing design issues from a selection of case studies. It may be regarded as a primer for the CIBSE Applications Manual "Natural ventilation in non-domestic buildings" which describes in much more detail how to decide if natural ventilation is appropriate, and if so, how to design and implement a successful natural ventilation strategy.

case study, economic considerations

#NO 12422 Design methods for ventilation systems in residential and commercial buildings.

Blomsterberg A, Delmotte C, Barles P, Pennycook K, de Gids W, Hardegger P, Maldonado E

UK, Garston, BRE, 1999, proceedings of Indoor Air 99, the 8th International Conference on Indoor Air Quality and Climate, and the Air Infiltration and Ventilation Centre (AIVC) 20th Annual Conference, held Edinburgh, Scotland, 8-13 August 1999, Volume 4, pp 7-12.

The development of guidelines for smart innovative mechanical ventilation systems is a task included in an ongoing research project partly supported by the European Commission in the framework of the Joule programme "TIPVENT - Towards Improved Performances of mechanical VENTilation systems". Before starting the actual work with the guidelines a survey was carried out to determine the level of current design methods for ventilation systems in the participating countries (Belgium, France, Great Britain, the Netherlands, Portugal, Sweden and Switzerland).

A simplified questionnaire was developed and sent to the participating countries. Examples of questions are: current traditional design procedure, whether indoor air quality and energy is taken into account by the HVAC-designer, rules of thumb, handbooks, guidelines, design tools and computer software.

The conclusions are that current traditional design often involves simple calculations, rules of thumb and manufacturers' design programs and catalogues. Traditional design seldom involves advanced calculations. Many different handbooks and guidelines are also used. These are some of the reasons why innovative ventilation systems are seldom introduced. In the paper the current design methods are presented and discussed.

mechanical ventilation

#NO 12430 Energy analysis of commercial buildings in subtropical climates. 

Lam J C

UK, Building and Environment, No 35, 2000, pp 19-26, 7 figs, 15 refs.

The overall thermal transfer value (OTTV) concept has been extended to correlate the OTTV of building envelope designs with other key building design parameters through DOE-2 computer simulations. A survey of 146 commercial buildings completed between 1975 and 1995 provides the information on the prevailing architectural designs and construction practices in Hong Kong. This information forms a basis for the development of a generic office building used in the computer analysis. Four major design aspects have been considered, namely the building envelope, indoor design conditions, internal loads and heating, ventilation and air-conditioning (HVAC). Implications for energy efficiency in the commercial sector energy use are discussed.

building design

#NO 12457 Advanced ventilation design for commercial, industrial and institutional facilities: Displacement and demand-controlled ventilation can be applied in combination with enthalpy recovery.

Turner W A

USA, Heating, Piping and Air Conditioning, October 1999, pp 61-66, 6 figs.

Describes how displacement and demand-controlled ventilation can be applied in combination with enthalpy recovery. Focuses on the indoor air quality components of IEQ, and also touches on IEQ and "sustainability" concerns along the way. Brief case studies from office, educational, and industrial buildings are presented to support the design concept discussions.

heat recovery, ventilation design

#NO 12515 Evaluating active desiccant systems for ventilating commercial buildings.

Harriman L G, Witte M J, Czachorski M, Kosar D R

USA, ASHRAE Journal, October 1999, pp 28-37, 7 figs, 2 tabs, 9 refs.

States that over the last 15 years, active desiccant systems have become a common component of HVAC systems in commercial buildings needing lower-than-usual humidity levels. Ice arenas, supermarkets and refrigerated warehouses all contain refrigeration systems which cool air more effectively when most of the building's moisture load is removed by an active (heat-reactivated) desiccant system. Cost savings, comfort improvements and "process benefits" of extended-season operation for ice rinks, lower product temperature for supermarkets and improved safety for warehouses are usually enough to make the desiccant component a useful addition to such buildings.

air conditioning

#NO 12531 Hybvent Forum '99 Proceedings.

Chen Z, Delsante A, Li Y, Rowe D (eds.)

Australia, CSIRO and the University of Sydney, and IEA Energy Conservation in Buildings and Community Systems (ECBCS) Annex 35, 1999, proceedings of Hybvent Forum '99, First International One-Day Forum on Natural and Hybrid Ventilation, held at the University of Sydney, Darlington, NSW, Australia, 28 September 1999, 191 pp.

The papers in the proceedings are divided into sections including: international projects; adaptive thermal comfort; ventilation processes; hybrid ventilation design and strategies; commercial building; residential buildings; industrial and educational buildings; experimental study; and analysis tools.

hybrid ventilation

#NO 12618 The impact of demand-controlled and economizer ventilation strategies on energy use in buildings.

Brandemuehl M J, Braun J E

USA, ASHRAE Transactions, Annual Meeting 1999, Seattle, 11 pp, 12 figs, 8 tabs, refs.

The overall objective of this work was to evaluate typical energy requirements associated with alternative ventilation control strategies for constant air volume (CAV) systems in commercial buildings. The strategies included different combinations of economizer and demand controlled ventilation, and energy analyses were performed for four typical building types, eight alternative ventilation systems, and twenty U.S. climates. Only single zone buildings were considered so that simultaneous heating and cooling did not exist. The energy savings associated with economizer and demand controlled ventilation strategies were found to be very significant for both heating and cooling. In general, the greatest savings in electrical usage for cooling with the addition of demand controlled ventilation occur in situations where the opportunities for economizer cooling are less. This is true for warm and humid climates and for buildings that have relatively low internal gains (i.e., low occupant densities). As much as 20% savings in electrical energy for cooling were possible with demand controlled ventilation. The savings in heating energy associated with demand controlled ventilation were generally much larger but were strongly dependent upon the building type and occupancy schedule. Significantly greater savings were found for buildings with highly variable occupancy schedules and large internal gains (i.e., restaurants) as compared with office buildings. In some cases, the primary heating energy was virtually eliminated by demand controlled ventilation as compared with fixed ventilation rates. For both heating and cooling, the savings associated with demand controlled ventilation are dependent on the fixed minimum ventilation rate of the base case at design conditions. 

carbon dioxide controlled ventilation, cooling, energy saving

#NO 12620 Association of ventilation rates and CO2 concentrations with health and other responses in commercial and institutional buildings.

Seppanen O A, Fisk W I, Mendell M J

Indoor Air, No 9, 1999, pp 226-252, 7 tabs, refs.

This paper reviews current literature on the associations of ventilation rates and carbon dioxide concentrations in non residential and non industrial buildings (primarily offices) with health and other human outcomes. Twenty studies, with close to 30,000 subjects, investigated the association of ventilation rates with human responses, and 21 studies, with over 30,000 subjects, investigated the association of carbon dioxide concentration with these responses. Almost all studies found that ventilation rates below 10 Ls-1 per person in all building types were associated with statistically significant worsening in one or more health or perceived air quality outcomes. Some studies determined that in creases in ventilation rates above 10 Ls-1 per person, up to approximately 20 Ls-1 per person, were associated with further significant decreases in the prevalence of sick building syndrome (SBS) symptoms or with further significant improvements in perceived air quality. The carbon dioxide studies support these findings. About half of the carbon dioxide studies suggest that the risk of sick building syndrome symptoms continued to decrease significantly with decreasing carbon dioxide concentrations below 800 ppm. The ventilation studies reported relative risks of 1.5-2 for respiratory illnesses and 1.1-6 for sick building syndrome symptoms for low compared to high low ventilation rates.

carbon dioxide, sick building syndrome, commercial building

#NO 12662 Marketing duct cleaning services by creating a partnership with building owners and managers. 

Price M

DucTales, March 1994, Vol 6, No 2, pp 20-27.

Argues that duct cleaning should be marketed as an indoor air quality programme that includes identification of problems, a detailed inspection and evaluation of the building systems, and practical, cost-effective recommendations to improve the air quality within buildings, which may or may not include duct cleaning. Deals with conducting a ventilation systems inspection. Discusses the suitability for this service of commercial office buildings, buildings under construction or renovation, hospitals, hotels and schools. Describes the marketing approach - targeting the audience and the sales presentation, outlining the benefits of the service, pricing and closing the sale.

duct cleaning services, indoor air quality, office building

#NO 12712 Characterizing building ventilation with the pollutant concentration index: results from field studies.

Faulkner D, Fisk W J, Sullivan D P, Thomas J M

in: USA, ASHRAE, 1999, "IAQ and Energy 98: Using ASHRAE Standards 62 and 90.1", pp 27-35, 2 figs, 3 tabs, refs.

A new method for characterizing ventilation in commercial buildings using the pollutant concentration index (PCI) was evaluated via field studies in four buildings. The PCI parameter quantifies the effectiveness of ventilation in controlling air pollutant exposures for pollutants released continuously and spatially uniformly within the building. For the measurements, passive tracer gas sources, spaced uniformly per unit floor area, simulated an indoor pollutant. The sources continuously released the tracer gas at a known rate. During the occupied periods of several days air samples from seated breathing-level locations were collected in gas storage bags. The PCI values were based on the tracer gas concentrations in the sample storage bags and on the indoor tracer gas emission rate. The technique was successfully implemented in buildings ranging in floor area from 130m2 to 4475m2. Results of these studies indicated that the spacing of tracer gas sources, between 8m2/source and 73m2/source, had little effect upon measured values of the PCI. The agreement between PCI values measured simultaneously with two different tracers was usually within 15%. The precision of PCI measurements made with a single tracer gas was approximately 5%. Measured PCI values were referenced to predicted values for buildings that meet minimum ventilation standards. PCI values also indicated the spatial and temporal variability of the effectiveness of ventilation in controlling pollutant exposures.

field monitoring, commercial building, pollutant

#NO 12722 Energy impacts of infiltration and ventilation in U.S. office buildings using multizone airflow simulation.

Emmerich S J, Persily A K

in: USA, ASHRAE, 1999, "IAQ and Energy 98: Using ASHRAE Standards 62 and 90.1", pp 191-203, 8 tabs, refs.

With the exception of a few analyses of the impacts of ANSI/ASHRAE Standard 62-1989 and energy use in specific buildings, the energy use in commercial buildings due to infiltration and ventilation flows has received little attention. However, as improvements have been made in insulations, windows, etc, the relative importance of these airflows has increased. The energy impacts of infiltration and ventilation flows in U.S. office buildings was estimated based on the analysis of a set of 25 buildings developed to represent the U.S office block stock. The energy calculation was performed by a bin method with infiltration flows determined by multizone airflow modelling. The results show that infiltration is responsible for about 13% of the heating load and 3% of the cooling load for U.S office buildings. In newer buildings, infiltration is responsible for about 25% of the heating load and 4% of the cooling load due to the higher levels of insulation. The total annual energy impact of infiltration in U.S office buildings is 60PJ of heating energy (15% of the total heating energy) and 6PJ of cooling energy (4% of the total cooling energy). It is also estimated that heating and cooling energy use due to ventilation is 17PJ at a rate of 2.5L/s (5 cfm) per person and 138PJ at 10L/s (20 cfm) per person. The results also show the potential energy savings due to tightening building envelopes and better control ventilation system airflows. This calculation of the national energy impacts of infiltration and ventilation in office buildings is a rough estimate, with its accuracy limited by the calculation method and input data. This paper presents an intermediate step of this analysis, and an improved estimate will be calculated with a combined multizone airflow and building energy simulation model.

air infiltration, multizone air flow modelling

#NO 12723 Architectural alternatives for IAQ and energy efficiency.

Loftness V, Harfkopf V, Lee S, Mahdavi A, Mathew P, et al

in: USA, ASHRAE, 1999, "IAQ and Energy 98: Using ASHRAE Standards 62 and 90.1", pp 247-256, 9 figs, refs.

Numerous studies have shown that buildings in the U.S. consume at least 30% to 50% more energy than they need to deliver present environmental qualities while at the same time not providing adequate air quality. This paper describes a range of architectural alternatives for improved indoor air quality and energy efficiency in commercial buildings. It argues for a complete reintroduction of regionalism in design through techniques such as "architecture unplugged", and "ascending" environmental conditioning strategies combined with "cascading" energy use strategies. This paper gives illustrative examples of high-performance buildings worldwide that manifest these approaches through the appropriate integration of enclosure and mechanical and interior systems. 

indoor air quality, building design, commercial building

#NO 12770 Duct systems in large commercial buildings: physical characterization, air leakage, and heat conduction gains.

Fisk W J, Delp W, Diamond R, Dickerhoff D, et al

Energy and Buildings, No 32, 2000, pp 109-119, 5 figs, 4 tabs, 13 refs.

Through field studies in large commercial buildings and reviews of building plans, we investigated the effective leakage areas (ELAs), air-leakage rates, and conduction heat gains of duct systems. Different methods for measuring air-leakage rates were also compared. ELAs of supply ducts ranged from 0.4 to 2.0cm2 per square metre of floor area served, and from 1.0 to 4.8cm2 per square metre of duct surface area. On a per-unit-floor-area basis, these duct ELAs are comparable to the values measured in residences. The corresponding values of duct leakage class were 60 to 270, much higher than the range of 3 to 12 reported by ASHRAE [ASHRAE standard 111 - 1988, Practices for Measurement, Testing, Adjusting, and Balancing of Building Heating, Ventilation, Air Conditioning, and Refrigeration Systems, American Society of Heating, Refrigerating, and Air Conditioning Engineers, Atlanta, 1988] as attainable for quality duct construction and sealing practices when leakage at connections to duct-mounted equipment is not considered. The measured air-leakage rates as a percentage of the inlet air flow rate varied from 0% to 30%, with most of the measurements falling between 10% and 20%. Large inconsistencies among the air-leakage rates determined measurement procedures exemplifying the need for further development and evaluation of measurement methods. Heat gains between the outlet of the cooling coils and the supply registers caused supply air temperatures to increase, on average, by 0.6oC to 2oC. The corresponding values of conduction effectiveness were 0.75 to 0.90; thus, heat conduction decreased the cooling capacity of the supply air existing registers by 10% to 25%. Because these results are based on studies in only a few building, generalizations from these findings are premature.

duct system, commercial building, effective leakage area, air-leakage rate

#NO 12853 The effect of air duct cleaning on TVOC and fungi.

Kumagai K, Yoshizawa S, Itoh H, Shizawa K, Ikeda K

paper from "Healthy Buildings/IAQ '97", proceedings of a conference held Natcher Conference Center at National Institutes of Health, Bethesda, USA, September 27-October 2, 1997, Vol 1, pp 611-616, 8 figs, 11 refs.

In the mechanically ventilated rooms, odor is one of the most frequent causes of complaints from the occupants. Although there are many sources of odor, it is understood that HVAC system is one of the important sources in the room. There found many fungi inside the HVAC system, such as drain pan of the humidifier, the surface of the air duct and etc., and it is possible that they are the cause of the odor. As a measure against this, air duct cleaning is thought to be the most effective way of maintaining the HVAC system clean and keeping the occupant comfortable with good IAQ.

In this study we measured the TVOC and the numbers of fungi in the HVAC system and confirmed the effect of air duct cleaning on TVOC and fungi. The buildings measured were commercial ones in central Tokyo. TVOC was measured before and after the air duct system cleaning with a photo-acoustic spectroscopy gas monitor (Brul & Kjaer Type 1302). From the dust collected during the air duct cleaning, fungi's were sampled and cultured on PDA and the population was determined.

There was a correlation between the concentration of TVOC and the number of fungi. Also the concentration of TVOC decreased after the cleaning and show that air duct cleaning is effective to control the TVOC. 

ducts, organic compounds, fungi, odour

#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 12954 NADCA general specifications for the cleaning of commercial heating, ventilating and air conditioning systems. 

Anon

USA, National Air Dust Cleaners Association (NADCA), [1997].

This detailed "generic" specification is designed for engineers and project managers to modify to suit a specific cleaning project.

Describes the minimum requirements necessary for commercial HVAC system cleaning.

#NO 13055 Guidelines for performance based innovative mechanical ventilation systems.

Blomsterberg A

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 5

The development of guidelines for performance based innovative mechanical ventilation systems in residential and commercial buildings is included in the European Commission project TIPVENT "Towards Improved Performances of Mechanical Ventilation Systems". The overall aim of TIPVENT is to promote improved performances of mechanical ventilation systems and the introduction and implementation of innovative designs. The development of performance oriented procedures for designing, commissioning and maintaining mechanical ventilation systems plays a key role in the project. The target group for the guidelines is practitioners. The entire life cycle of a building, i.e. from the brief until deconstruction, is taken into consideration. The guidelines are summarised and discussed here.

The importance of performance specifications and their verification on-site are emphasised. Special attention is paid to efficient use of electricity, low sound levels, life cycle perspective, use of building energy management system and operation and maintenance. These are areas where the performance of ventilation systems can and should be improved using conventional and innovative technologies. From the life cycle perspective, it is stressed that life cycle cost analysis should be performed. Operational and maintenance instructions and monitoring are highlighted.

mechanical ventilation, system design, life cycle analysis

#NO 13078 Influence of building air tightness on ventilation losses.

Bernard A-M, Lemaire M-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 29.

Building air tightness is an important parameter in relation to ventilation systems performance and energy losses. Yet, the total amount of leakage is as important in relation to performance as the effective position in the room of the ventilation systems.

Some calculations have been run according to prEN 13465 from TC156 WG2 for different buildings (single house, dwellings and commercial buildings) varying air tightness, value and repartition for different ventilation systems (natural, mechanical exhaust, mechanical exhaust and supply). All these calculations have been compared, focusing on ventilation losses during the heating season in Paris. Some double zone calculations on the commercial building (offices and stock area) have also been run to compare with uniform single zone repartition.

Calculations confirm the importance of air tightness on ventilation losses and show variations due to repartition hypothesis which must therefore be chosen carefully. Very often, air-tightness value and its repartition are unknown and the hypothesis made on calculations are most important on results.

air tightness, heat loss, air leakage, ventilation performance

#NO 13149 Airtightness of commercial and institutional buildings: blowing holes in the myth of tight buildings.

Persily A K

USA, Atlanta, American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), 1998, proceedings of "Thermal performance of the exterior envelopes of buildings VII" a conference held Sheraton Sand Key Hotel, Clearwater Beach, Florida, 6-10 December 1998, pp 829-837, 5 figs, 3 tabs, refs.

It is often assumed that commercial and institutional buildings are fairly airtight and that envelope air leakage does not have a significant impact on energy consumption and indoor air quality in these buildings. Furthermore, it is also assumed that more recently constructed buildings are tighter than old buildings. The fact of the matter is that very few data are available on the airtightness of building envelopes in commercial and institutional buildings. The data that do exist show significant levels of air leakage in these buildings and do not support correlations of airtightness with building age, size or construction. This paper presents the airtightness data that are available and limited conclusions that can be drawn from these data.

air tightness, large building, building envelope, commercial building, public building

#NO 13154 Emerging trends for energy efficiency in buildings.

Bansal N K

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 350-355, 7 figs, 1 tab, 12 refs.

Technology to achieve energy efficiency in buildings is undergoing a rapid change. While the energy savings throughout building design and use of windows and insulation are fairly well understood, the development of advance windows, double façade system with natural ventilation for heat recovery, innovative daylighting systems, integration of photovoltaics into the building and energy controls are developing technologies, which have the potential of commercial viability in the near future. This review describes these emerging trends in building technology in a comprehensive manner.

energy efficiency, building design, advanced windows, daylighting, renewable energy


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