Building Services Engineers Research Articles

A study of passive ventilation integrated with heat recovery

To meet the demand for energy demand reduction in heating, ventilation and air-conditioning systems, a novel design incorporating a heat recovery device into a wind tower was proposed. The integrated system uses a rotary thermal wheel for heat recovery at the base of the wind tower. A 1:10 scale prototype of the system was created and tested experimentally in a closed-loop subsonic wind tunnel to validate the Computational Fluid Dynamics (CFD) investigation. Wind towers have been shown to be capable of providing adequate ventilation in line with British Standards and the Chartered Institution of Building Services Engineers (CIBSE) guidelines. Despite the blockage of the rotary thermal wheel, ventilation rates were above recommendations. In a classroom with an occupancy density of 1.8m2/person, the wind tower with rotary thermal wheel was experimentally shown to provide 9L/s per person at an inlet air velocity of 3m/s, 1L/s per person higher than recommended ventilation rates. This is possible with a pressure drop across the heat exchanger of 4.33Pa. In addition to sufficient ventilation, the heat in the exhaust airstreams was captured and transferred to the incoming airstream, raising the temperature 2°C, this passive recovery has the potential to reduce demand on space heating systems.

Investigating the Process of Exporting Autodesk Ecotect Models to Detailed Thermal Simulation Software

Autodesk Ecotect^[1] is a whole building simulation software that can predict the thermal, visual and acoustic performance of buildings. It is very user-friendly software that could potentially integrate with the architectural design process. Thermal performance analysis in Autodesk Ecotect is based on the Chartered Institution of Building Services Engineers (CIBSE) admittance method and thus inherits its limitations. Hence, the need to use more detailed thermal simulation tools during the final stage of a building design or research project. This paper investigated the potential of using detailed thermal simulation software (HTB2) in conjunction with Autodesk Ecotect. Five primary classrooms built in a hot-dry climatic region were monitored. The same classrooms were modelled in Autodesk Ecotect using several modelling techniques and the internal temperatures were simulated using HTB2. Analysis of results suggested that a number of necessary measures are required to ensure the reliability and accuracy of the simulation results.

The effectiveness of retrofitted green and cool roofs at reducing overheating in a naturally ventilated office in London: Direct and indirect effects in current and future climates

Mitigating summertime overheating is increasingly viewed as a key issue in urban planning – a warming climate and increasing urbanisation will exacerbate the problem. The effectiveness of green and cool roofs at reducing summertime overheating was assessed for a naturally ventilated, poorly insulated office roof in London. This was contrasted to the application of retrofitting traditional insulation. The new Chartered Institute of Building Service Engineers overheating criteria was used to assess the level of overheating as predicted by a whole building thermal simulation model. The impacts of the roofing strategies were split into the direct and indirect effects. The indirect effects of the roofs were modelled using microclimatic modelling software. The results indicate the direct effects of green and cool roofs at reducing overheating are much greater than the indirect cooling effect. A non-insulated cool roof was found to be the most effective strategy. By insulating the roof, the level of overheating was slightly reduced. Non-insulated green and cool roofs were more effective than insulated roofs at reducing levels of overheating. When using a 2050 weather file, the building frequently overheated without the use of green or cool roof.

A new approach for examination of performance of interior lighting systems

Abstract This paper presents a new approach for examination of insufficiency of a current lighting system and for performing maintenance plans of a lighting installation. Thus, a numerical algorithm based on finite element method (FEM) that ensures the required accuracy for illuminance calculations according to international lighting standards was developed. Experimental measurements were recorded in a controlled environment for the purpose of measuring the effectiveness of the algorithm. The average illuminance calculated according to CIBSE Code 1994 published by the Chartered Institution of Building Services Engineers (CIBSE) was obtained by error of 5.3% compared to the experimental measurements. Illuminance values of 894 points were calculated as 0.3% error according to the actual experimental measurements by proposed numerical algorithm that uses 36 pieces measurement data. Less experimental measurements provided more accurate results. The results obtained indicate that the suggested numerical model is very effective and usable in calculations of illuminance. In this way, this model will eliminate the requirement for long experimental measurements in lighting system controls that must be carried out periodically.

A data-processing approach for exploring water-use maneuver of high-rise building

Recognizing high-rise building water-use maneuver should be helpful for developing some practical strategies when indoor room space safety becomes a crucial feature in the building operation. This paper presents a data-processing approach for exploring the water-use maneuver of high-rise building. This approach combines the empirical mode decomposition and statistical analysis to process the mezzanine-floor air-pressure data measured in the drainage stack system of Li Ka-Shing building at PolyU of Hong Kong on 28th of April of 2008. Because the mezzanine-floor air-pressure signals in the building drainage system are recorded within about 10 hours with a recording rate of one signal per second, data re-sampling is obviously needed. Otherwise, the direct application of empirical mode decomposition should be unavailable because the mezzanine-floor air-pressure data are too massive. Statistical analysis is further encompassed after the empirical mode decomposition to seek the influences of re-sampling time interval and the empirical mode decomposition index so that the building water-use maneuver can be understood in detail. Practical application: From the viewpoint of Building Services Engineering, any occupied space should be safeguarded, because the depletions of the trap seals 1 and the bathroom floor drain traps 2 can result in cross-contamination via the drainage system. This suggests that it is crucial to investigate building water-use maneuver when indoor room space safety becomes urgent. To explore the water-use maneuver, an indirect way is by analyzing the mezzanine-floor air-pressure in the drainage stack system in terms of an appropriate approach. Since the mezzanine-floor air-pressure in the drainage stack system of an 18-floor building, i.e. Li Ka-Shing building at PolyU of Hong Kong has been recorded, 3 it can be used to propose the water-use maneuver approach which is helpful for developing some practical strategies for indoor room space safety when the safety should be carefully and urgently faced.

Designing a “Think-Along Dwelling” for People With Dementia: A Co-Creation Project Between Health Care and the Building Services Sector

Ageing-in-place is the preferred way of living for older individuals in an ageing society. It can be facilitated through architectural and technological solutions in the home environment. Dementia poses additional challenges when designing, constructing, or retrofitting housing facilities that support ageing-in-place. Older adults with dementia and their partners ask for living environments that support independence, compensate for declining and vitality, and lower the burden of family care. This study reports the design process of a demonstration home for people with dementia through performing a literature review and focus group sessions. This design incorporates modifications in terms of architecture, interior design, the indoor environment, and technological solutions. Current design guidelines are frequently based on small-scale studies, and, therefore, more systematic field research should be performed to provide further evidence for the efficacy of solutions. The dwellings of people with dementia are used to investigate the many aspects of supportive living environments for older adults with dementia and as educational and training settings for professionals from the fields of nursing, construction, and building services engineering.

Adaptive thermal comfort model for air-conditioned hospitals in Malaysia

This article presents an adaptive thermal comfort model study in the tropical country of Malaysia. A number of researchers have been interested in applying the adaptive thermal comfort model to different climates throughout the world, but so far no study has been performed in Malaysia. For the use as a thermal comfort model, which better applies to hot and humid climates, the adaptive thermal comfort model was developed as part of this research by using the collected results from a large field study in nine hospitals with 293 workers. The relationship between the operative temperature and behavioral adaptations was determined. In the developed adaptive model, the acceptable indoor neutral temperatures lay within the range of 23.3–26.5℃, with outdoor temperatures ranging between 25.4℃ and 35.0℃. The most comfortable temperature for hospital workers was 26.4℃. Practical implications: The new conclusions from the adaptive thermal comfort model in hospitals in the tropics could be used as an important guide for building services engineers and researchers. Their intentions are to minimize energy usage in HVAC systems in hospitals operating in the tropics while maintaining an acceptable thermal comfort level and thus improving the performance and well-being of hospital workers.

The next generation of experientially realistic lab-based research: The University of Sydney's Indoor Environmental Quality Laboratory

This article describes the University of Sydney's Indoor Environmental Quality Laboratory (IEQ Lab). This is a unique facility in which the building research community and the broader building sector can study how multiple factors comprising the indoor environment – including temperature, humidity, air movement, ventilation rates, air quality, day-lighting, artificial lighting, sound and acoustics – combine to affect human comfort, productivity and health. The IEQ Lab provides experientially realistic interior spaces in which samples of human subjects can be exposed to precisely controlled combinations of the key IEQ parameters. This facility aims to deliver research outcomes that are directly relevant to designers, building services engineers, property and facilities managers, and the cognate regulatory bodies. The IEQ Lab research findings will enhance sectoral capacity to provide innovative and sustainable, low-energy built environments that balance occupants’ expectations for quality against our obligations to substantively address climate change.

A portrait of building services engineers in Hong Kong

PurposeAs part of a study that aimed at enhancing the future roles and functions of building services (BS) engineers in Hong Kong, a survey was carried out to obtain demographic information about BS practitioners as well as their views and opinions on a range of issues which affect professional practices of BS engineers and recognition of their contributions by others. The purpose of this paper is to give a portrait of BS engineers in Hong Kong.Design/methodology/approachA series of statistical analyses were conducted based on the responses given by the BS practitioners, which included their qualifications, experience, job field, annual income and the number of trades of BS systems that they are competent in and responsible for.FindingsThe statistics show that: competence gap exists in that BS engineers are required to handle more trades of BS systems than those they are competent in; and the academic and professional qualifications, years of experience and job position are the key influential factors to the annual income of BS engineers but little differences exist in the average annual income of engineers in different job fields.Originality/valueThe competence gap is a concern that needs to be addressed to ensure BS engineers are competent in handling the common trades of BS systems, which is increasingly important for them to perform effectively in integrated professional teams for turning out holistic solutions for sustainable building developments.

A review on predicted mean vote and adaptive thermal comfort models

This paper presents a literature review of the Fanger’s predicted mean vote and adaptive thermal comfort models developed in different buildings and climates. An important premise of this paper is the fact that Fanger’s model underestimates the thermal impression in the actual case and thus is no longer valid for use in certain climates. As a consequence, many researchers have developed adaptive models from field studies for different climates and countries. However, there is still no adaptive model that can be applied in designing air-conditioning systems for different buildings in all tropical climate countries. Based on this comprehensive review, an internationally recognized adaptive model is needed to achieve better thermal conditions in a variety of buildings such as hospitals, offices, factories, lecture halls, museums, hotels and libraries in the tropics. Practical application: The new conclusions from the comprehensive review on an adaptive thermal comfort model in buildings in the tropics could be used as an important guide for building service engineers and researchers. Their intentions are to minimize energy usage in heating, ventilation and air conditioning (HVAC) systems in buildings such as hospitals, offices and lecture halls operating in the tropics while maintaining an acceptable thermal comfort level and thus improving the performance and well-being of the occupants.

Climate change implications for HVAC&R systems for a large library building in Malaysia

The air conditioning systems play an important role in providing a comfortable and safe environment for occupants as well as a suitable condition to store books in the library via proper control of the indoor conditions. This paper presents the research conducted on the maximum required cooling load based on the climate change scenario in the future for a large building. In order to present the worst-case condition inside the library, the maximum number of heat gain from occupants and electrical devices is considered. For this research, the main library of University of Malaya is selected for data collection, analysis and simulation. The existing air conditioning systems are modelled via TRNSYS software as a baseline model. Three sets of future Typical Meteorological Year (TMY2) data files for Kuala Lumpur are developed in the UK to be used for simulation in the TRNSYS to analyse the maximum required cooling load for two sections of the main library building. Based on the comparison of the result in the year 2000, it can be estimated that the required cooling load for years 2020 and 2050 is estimated to be increased from 4.1% to 4.8% and 10% to 11.8%, respectively. Practical application: The good amount of technical information of real application conducted on the required maximum cooling load in a large building for years 2020 and 2050 is estimated to increase from 4.1% to 4.8% and 10% to 11.8% respectively in the tropics could be used as an important guide for building services engineers and researchers who are intending to optimise HVAC&R system design in large buildings operating in tropical countries in the future.

Simulating urban heat island effects with climate change on a Manchester house

This article presents a methodology for determining the internal temperatures of a post-1919 mid-terrace house for the present-day and a future (2050) climate. The Meteorological Office, Hadley Centre regional climate model has been run with urban parameterisation and an improved land-surface scheme with urban heat island forcing and a weather generator to quantify the effect of the urban heat island. Manchester city dry-bulb air temperatures are shown to be of the order of 4 K higher than those for the present-day under a UKCP09 medium emissions scenario. Extreme summer temperature data (99% percentile) are used to produce a cooling design day for use in a building simulation program.1 Loft and wall insulation decreases internal air temperatures by up to 17% and low e glazing with louvres by up to 8%. Internal temperatures for a 2050 climate will exceed existing Chartered Institution of Building Services Engineers thresholds. Practical application: Climate change is an important subject for both the building industry and local authorities. Climate change scenarios produced by the Hadley Centre General Circulation Models (GCM) have been downscaled to the local level for use in a building simulation model.1 This article demonstrates a technique that enables data from a GCM to be used within a building simulation program1 for an urban environment. It also examines the implications of the combined effect of the urban heat island and climate change on the adaptation options available to designers and planners for existing and future buildings.

A Delphi study on building services engineers' core competence and statutory role in Hong Kong

PurposeThe purpose of this paper is to narrow the diverse views of the industry stakeholders on two controversial issues, namely the scope of core competence of building services engineers (BSEs) and the statutory role that they should play, which were encountered in an extensive research study on the building services profession of Hong Kong.Design/methodology/approachAn expert panel was formed and the Delphi method was applied to resolve the controversies. In the Delphi process, every panel member was provided with complete opinions expressed by all other panel members in each round of the deliberation.FindingsSufficient support was found for the proposition that professional BSEs should be competent in handling air‐conditioning, electrical, fire services, and plumbing & drainage works, and that the government authorities should mandate the design and compliance certification of electrical and fire services installations by BSEs.Research limitations/implicationsAlthough the Delphi method has not been hitherto applied to resolve the controversies addressed in the study, it was proven to be a very effective tool in seeking majority opinions from a group of experts. The same approach may be taken in similar studies in future.Practical implicationsThe core competence identified should be made as a minimum requirement for practitioners who wish to practise as professional BSEs. The views and comments given by the expert panel members are informative references to public policy makers.Originality/valueThis was the first ever study conducted in an attempt to identify the core competence and statutory role of BSEs in Hong Kong.

A low-order canyon model to estimate the influence of canyon shape on the maximum urban heat island effect

A simple mathematical model of an urban canyon is developed. The canyon model consists of horizontal and vertical slabs providing thermal storage for heat and absorption of and shielding from solar radiation and long wave radiation to the sky. The model is compared to a horizontal slab in a rural location to examine the effect of the canyon shape. The results show the same trend as measurements by others, with increasing urban heat island (UHI) effect with increasing canyon aspect ratio. The model is then used to determine the maximum UHI effect by producing a simple algebraic equation. This compares well with measurements in Greater Manchester of canyon and rural temperatures although some empirical adjustments are required. The strong influence of cloud cover is shown by the model and measurements as are the canyon shape and the ground temperature. Practical applications: The model is simple and developed in terms applicable to building services engineers, using ventilation rates through the canyon. It also does not require more than the standard weather data available in a CIBSE Test Reference Year or a Design Summer Year. From this model, the UHI effect can be developed to adjust the data from a rural site to that of an urban and city centre site. This is useful for building designers to take account of the UHI effect which they cannot do at present. This would also be useful for UKCP09 data which have been released.

Generating design reference years from the UKCP09 projections and their application to future air-conditioning loads

A method is developed to generate future design reference year (DRY) data from the United Kingdom Climate Impact Programme's 2009 (UKCP09) climate change projections for a variety of future time horizons and carbon emission assumptions. The method selects three near-extreme summer months and three near-extreme winter months and weaves them into an existing test reference year (TRY). Risk levels associated with the 85th percentile (broadly equivalent to existing Chartered Institution of Building Services Engineers [CIBSE] design summer years) of the cumulative distribution function of dry-bulb temperature and, for comparison, the 99th percentile are used. A comparison is made with DRYs generated using alternative methods from other research groups. The data are applied to future air-conditioning (cooling) loads analysis for a wide range of non-domestic case study building types. Simulations using a control DRY set applied to these buildings are used to develop a simplified regression-based calculation method for predicting future air-conditioning loads. The simplified model is shown to be applicable to future weather data without loss of accuracy, which makes it possible to carry out large numbers of future cooling loads predictions without the need to perform extensive and complex energy simulations. Practical applications: It is becoming increasingly necessary to design energy and comfort services for buildings with a whole-life perspective. To assist with this, the CIBSE future weather years can be used for building simulations through to the 2080s. In June 2009, the UK’s Department of the Environment, Food and Rural Affairs (Defra) with the support of the United Kingdom Climate Impacts Programme (UKCIP) published updated climate change projections using a probabilistic method. In future, the responsibility will rest with designers to select design data from a large number of probabilistic outcomes. This work develops a technique to select design weather data called a DRY at two alternative risk levels for use in building simulations through to the 2080s. A simplified method is also proposed to allow practitioners to generate large numbers of probabilistic design cooling loads without the need to perform extensive simulations.

IMPACTS OF VENTILATION: STUDIES ON “BEFORE AND AFTER” A SMOKING BAN IS IMPLEMENTED / VĖDINIMO POVEIKIS: TYRIMAI PRIEŠ ĮVEDANT IR ĮVEDUS RŪKYMO DRAUDIMĄ / ВОЗДЕЙСТВИЕ ВЕНТИЛЯЦИИ: ИССЛЕДОВАНИЕ ДО И ПОСЛЕ ЗАПРЕТА НА КУРЕНИЕ

A number of legislative bodies in Europe have already made or are currently considering making policy decisions on the issue of smoking in public places. Policy alternatives have been discussed in Town and Country Planning (2002). In the last decade, the scientific evidence relating to this debate has been reported in a diverse range of publications such as the British Medical Journal, Indoor Air and The Chartered Institution of Building Services Engineers journal. On inspection much of this reporting concludes negatively on the performance of ventilation systems. In this paper, a critical review is undertaken of the “before and after smoking ban” study papers. This paper aims to critically review the findings of these studies in relation to ventilation and draw some working conclusions from these studies. Santrauka Daug teisinių institucijų Europoje jau padarė ryžtingus sprendimus rūkymo viešose vietose klausimais ar dar svarsto dėl jų priėmimo. Apie alternatyvas buvo diskutuojama Town & Country. Būta įvairių publikacijų, susijusių su šiomis diskusijomis, pateikta mokslinių įrodymų, pavyzdžiui, Didžiosios Britanijos Medical Journal, Chartered Institution of Building Services Engineers leidiniuose. Daug išvadų siejasi su negatyviu ventiliacijos sistemų veikimo vertinimu. Apžvalga atliekama ištyrus situaciją prieš įvedant rūkymo draudimą ir jį įvedus. Siekta peržiūrėti tyrimų, susijusių su vėdinimu, išvadas ir padaryti tam tikrus sprendimus. Резюме Многие правовые институции в Европе уже приняли решения или рассматривают возможность принятия реше- ний, касающихся вопроса о курении в общественных местах. Дискуссия о возможных альтернативах велась в Town & Country. Дискуссиям на эту тему было посвящено немало публикаций, представлены научные доказа- тельства, например, в издаваемых в Великобритании журналах Medical Journal, Chartered Institution of Building Services Engineers. Во многих выводах приводится негативная оценка действия систем вентиляции. Приводимый в статье анализ основан на исследовании ситуации до введения запрета на курение и после его введения. Пред- принята попытка оценить выводы исследований, касающихся действия систем вентиляции, и предложить опреде- ленные решения.

Using localised weather files to assess overheating in naturally ventilated offices within London's urban heat island

Urban environments typically experience increased average air temperatures compared to surrounding rural areas – a phenomenon referred to as the Urban Heat Island (UHI). The impact of the UHI on comfort in naturally ventilated buildings is the main focus of this article. The overheating risk in urban buildings is likely to be exacerbated in the future as a result of the combined effect of the UHI and climate change. In the design of such buildings in London, the usual current practice is to view the use of one generic weather file as being adequate to represent external temperatures. However, the work reported here demonstrates that there is a considerable difference between the overheating performance of a standard building at different sites within London. This implies, for example, that a building may wrongly pass or fail criteria used to demonstrate compliance with building regulations as a result of an inappropriate generic weather file being used. The work thus has important policy implications. Practical application: The Greater London Authority has recently developed, with the Chartered Institute of Building Services Engineers, guidance for developers to address the risk of overheating in buildings via the provision of weather files for London relating to three zones. While such an initiative is welcomed, it may be that a weather file tailored to the building location would be preferable. Of course, this would add further complexity to the process and a view would have to be taken as the viability of such an approach. The work presented in this article, however, suggests that serious consideration should be given to the use of tailored weather data for regulatory purposes.

Closure to “Win-Win Concession Period Determination Methodology” by Xueqing Zhang

Min Wu; Kwong Wing Chau; and Qi Ping Shen Professor, Management School, Chongqing Jiao Tong Univ., P.R. China (on leave); Instructor, Dept. of Building Services Engineering, Hong Kong Polytechnic Univ., Hung Hom, Kowloon, Hong Kong (corresponding author). E-mail: bewumin@polyu.edu.hk Chair Professor, Dept. of Real Estate and Construction, Univ. of Hong Kong. E-mail: hrrbckw@hku.hk Chair Professor and Head, Dept. of Building and Real Estate, Hong Kong Polytechnic Univ., Hung Hom, Kowloon, Hong Kong. E-mail: bsqpshen@inet.polyu.edu.hk

Experimental application of particle imaging to fluid velocity analysis in building drainage systems

Previous research into the hydraulic and pneumatic conditions in the pipework associated with building drainage waste and ventilation (DWV) systems has been interpreted as suggesting that the flow regime within the vertical stack consists of an annular water flow entraining a central air core with an associated pressure drop. However, previous evidence had suggested that a significant proportion of the water was found in the air core by Pink [A study of the effect of stack length on airflow in drainage stacks. BRE Current Paper, 1973; 38/73] and Wyly and Eaton [1961. Capacity of stacks in sanitary drainage systems for buildings. U.S. Department of Commerce, National Bureau of Standards, Monograph 3]. A new model has recently been proposed by Campbell and MacLeod [Investigation of the causative factors of airflow entrainment in building drainage-waste-ventilation (DWV) systems. Building Services Engineering Research Technology 1999; 20(3): 99—104] which suggests that the airflow entrainment is due to the distribution of work between the water annulus and the droplets falling in the central air core. This article describes the investigation of the velocity profile of mixed-phase fluid flow in building DWV systems utilising the particle tracking velocimetry (PTV) flow measurement technique previously established by Campbell [The application of particle tracking velocimetry as a velocity measurement technique. Building Services Engineering Research Technology 2006; 27(4): 327—40]. PTV is a non-intrusive optical flow measurement technique that supplies an instantaneous sample of velocity throughout a two-dimensional plane in the flow field. The results of the PTV investigation support the assumption that water droplets exist in the air core and have a velocity greater than that of the water annulus. Practical application: This article describes the application of particle tracking velocimetry (PTV) to the interaction between air and water in typical building drainage waste and ventilation (DWV) systems. Results indicate an unexpected distribution of mass across the stack discharge which, together with the nature of the air/water interface, governs air movement. The technique of PTV is particularly suited to this area, and represents the first steps towards eventual refinement of mathematical models designed to simulate building DWV system behaviour.

Analyses of heat recovery devices in the HVAC system in an operating theatre in the tropics

The air-conditioning system is the major electricity consumption for the non-domestic buildings. A significant part of energy savings can be achieved if heat recovery technologies such as run-around coils, plate-to-plate heat exchangers, heat recovery wheels and heat pipe heat exchangers are incorporated into the ACMV system of these buildings. Non-domestic buildings, such as hospitals, expense even more energy as the supply of fresh air into the space is deemed necessary. For example, air must be changed at least 25 times hourly and recirculation of RA is prohibited for the operating theatres. Therefore, an operating theatre of a hospital in a tropical climate country was chosen for this research. The performance of the existing air-conditioning system has been thoroughly studied to investigate the potential in energy savings in the building. The transient system simulation program (TRNSYS) was used to analyse the air-conditioning system incorporated with heat recovery devices. Generally, there are eight heat recovery systems analysed using TRNSYS, which divided into two groups: the heat recovery ventilating system and heat recovery dehumidification system. The energy savings, payback period, dehumidification enhancement, stability of indoor air conditions and preventing the cross contamination, for each of the systems, were analysed in comparison to each other. Based on this study, it is recommended that the heat recovery systems should be installed to enhance moisture removal and reduce energy usage of HVAC system operating in hospitals. Practical application: The good amount of technical information of real application conducted on heat recovery devices installed in HVAC systems in operating theatres in the tropics could be used as a comprehensive guide for building services engineers and researchers who are intending to apply heat recovery devices as ‘coolness’ recovery and dehumidification devices in HVAC systems operating in tropical countries.