An Assessment of Thermal Comfort in Multi Storey Office Buildings in Ghana

Amidst the recent development in the usage of curtain walls for office buildings, high utilization of energy and poor thermal comfort issues have become paramount. This paper assesses thermal comfort in multi storey (naturally and mechanically ventilated) office buildings in Accra, the Capital city of Ghana using Fanger’s Predicted Mean Votes (PMV) and Predicted Percentage of Dissatisfied persons (PPD) model. The model relates to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 55 (which gives an acceptable temperature range of 23℃ - 26℃) and the International Standards Organization (ISO) 7730. Indoor environmental parameters (temperature and relative humidity) of 4 multi storey office buildings were recorded over a 10 month period. The environmental parameters were analyzed using PMVcalc_v2 software which resulted in the generation of PMV-PPD values. The findings reveal high PMV-PPD values in the Naturally Ventilated Building (NVB) whiles the Mechanically Ventilated Buildings (MVB) fall within the comfort zone. Meanwhile, the Actual Mean Votes (AMV) by the occupants suggest all four buildings are relatively comfortable with the mechanically ventilated offices being more comfortable. Additionally, it is recommended that buildings are orientated with their longer sides facing north-south, with enough shading in order to improve the thermal comfort conditions of work spaces.

The Structural Behavior of Low/Medium/High Rise Concrete Office Buildings in Kuwait

The main concern of this paper is to provide an extensive study for the structural behavior of low/medium/high rise office buildings aiming to deepen structure and architect designers understanding for such type of buildings. The study is performed on reinforced concrete and emphasized only on Kuwait city conditions for wind. Regular layout plan building with different heights ranging from five to fifty typical office stories are investigated in this study. Three dimensional finite element techniques through ETABS software are used in conducting analysis for structures presented here-in. A serviceability study is performed to ensure that buildings have sufficient stability to limit lateral drift and peak acceleration within the acceptable range of occupancy comfort. In addition, an ultimate strength study is carried out to design and verify that all the structural elements are designed to withstand factored gravity and lateral loadings in a safe manner according to the international building codes. The building slenderness ratio and the building core size and location are the studied parameters since they are the key drivers for the efficient structural design. Analysis results are presented and discussed and finally conclusions are summarized as guidelines for designers of concrete office buildings in Kuwait.

Preventive Maintenance Characteristics towards Optimal Maintenance Performance: A Case Study of Office Buildings

Lack of preventive measure is currently the problem that implicates poor building maintenance performance and issue on sustainability of buildings in Malaysia. Whereby, preventive maintenance is an effective approach to enhance the reliability and quality of a system and its components. This study seeks to investigate the characteristics of preventive maintenance towards the overall performance in building maintenance. Case study approach is adopted to identify the maintenance characteristics and aspects that lead to good performance. The research findings demonstrate that the most significant maintenance characteristics towards overall performance are skill and knowledge of maintenance labour, quality of spare parts and materials, length of predetermined maintenance interval, skill and knowledge of maintenance manager, capability to adopt maintenance equipment and technique, budget allocation for acquisition of maintenance data, reliability of maintenance data, as well as frequency of monitoring and inspection. As a conclusion, the significant maintenance characteristics must be taken into consideration to achieve optimal maintenance performance. In order to improve the effectiveness of maintenance strategy and the maintenance performance, the study recommends practice and provision of communication platform such as meeting and customer satisfaction survey that involves all the key participants from clients to customers.

DHW Design Flow Rates and Consumption Profiles in Educational, Office Buildings and Shopping Centres

The paper gives a thorough survey of the studies of different authors in the field of domestic hot water (DHW) consumption and consumption profiles. It presents an overview of the research done into DHW by the Tallinn University of Technology. Working out on the basis of investigations has been new empirical formulas for determining design flow rates for schools, kindergartens, office buildings and shopping centres. DHW consumption profiles of typical buildings are presented. Comparisons are given on the determination of DHW design flow rates by the standard EVS 835, the EN 806-3 and the recommended formulas. The latter makes it possible to considerably decrease the design flow rates which in turn enables to deminish the load of the equipment, to improve the quality of control and to decrease the diameters of the pipes of the district heating network and the losses of heat in them.

Shifting Ground - Changing Attitudes to the Green Revitalization of New Zealand＇s Existing Office Buildings

This paper explores the shift in the attitudes of building developer/owners to the incorporation of sustainability measures into office building renovations in New Zealand over the last 7 years, through a series of interviews with a wide range of key industry players and the study of three seminal case study examples. The interviewees uniformly considered that there had been a rapid increase in interest in the green renovation of existing buildings during the period under consideration, due mainly to strong leadership by central government. Significant differences in attitudes to green renovation emerged between the various groups as to whether, and on what terms such developments were likely to occur. The move to green building solutions seems to have continued in New Zealand, despite the world financial crisis and central government＇s abrogation of its leadership role being replaced by rising tenant expectations and the need for building owners to let their premises in a more competitive leasing environment. The change in attitudes demonstrated is profound. In the earliest of the case study buildings, started on site in 2004, no consideration is given by the developer, owner or design team to sustainability issues and there is no obvious user demand. In the second case, which started on site only one year later, sustainable design is very prominent, but is largely tenant driven, albeit with the active and enthusiastic support of the developer and design team. The final case study building started on site in 2007 is entirely developer/building owner driven and stems from a perception that ＂green＂ buildings represent value for money, that there is a real and persistent user demand and that sustainable design makes strong commercial sense.

Sensibility Analysis of the Brazilian Standards for Energy Efficiency Regarding the Variation of Internal Load Density in Office Buildings in Brazilian Bioclimatic Zones 1 and 7

The RTQ-C （Technical Requirements of Quality for the Energy Performance Level of Commercial Buildings） publication classified the buildings in five efficiency levels. In RTQ-C, the evaluation can be done with two methods： a prescriptive method and a simulation one. This paper aims to identify the sensibility of the prescriptive method RTQ-C regarding the variation of equipment internal load density in office buildings in bioclimatic Zones I and 7 of the Brazilian bioclimatic zoning. The research results show that the building with walls and roof configured to meet specific prerequisites for energy efficiency Levels B and C had a lower consumption than buildings that meet the prerequisites to Level A. The study also showed that buildings with high internal load density of equipment, maximum shape factor and high, with walls and roofs with higher thermal transmittance, have lower power consumption than constructions with an envelope with greater thermal resistance. The increase in internal load density causes an increase in the internal heat generated by the large amount of equipment. In buildings with higher thermal insulation （Level A）, the internal heat is maintained in the environment, causing overheating and the need for an air conditioning system.

Occupant Behavior: A “New” Factor in Energy Performance of Buildings - Methods for Its Detection in Houses and in Offices

The role that occupants have on energy consumption and performance of buildings is known,but still requires a great deal of research.In this paper,the most common techniques to detect occupancy and occupant behavior in buildings are categorized with their advantages and disadvantages.Being the buildings characterized by different energy usage,the presentation of the studies that applied surveys and monitoring campaigns is conducted with differentiation between residential and office buildings.

Faults and Claims about Thermal Environments in Relation to Energy Saving Measures in Smaller Office Buildings

Building equipment, energy-saving systems, and claims of inappropriate indoor thermal environments were analyzed in relation to the floor area using responses to a questionnaire survey of service managers of 157 buildings built in Osaka, Kyoto and Hyogo prefectures in Kinki area of Japan. Results show the following： （1） In smaller buildings （〈 5,000 m2）, setting temperatures are higher in summer and lower in winter, effects of ＂uncomfortable radiation from windows＂ are greater, energy-saving systems decrease indoor thermal comfort, but claims of ＂hot＂ and ＂cold＂ are fewer; （2） Claims of ＂hot＂ and ＂cold＂ are unrelated to the setting temperature and whether the air-conditioning control system is central or local; （3） The adoption rates of mitigation of dress codes （＂COOL-BIZ＂ and ＂WARM-BIZ＂） are higher than those of temperature mitigation of air conditioning.

Consumer Central Energy Flexibility in Office Buildings

Energy flexibility in buildings will play an important role in the smart energy system. Office buildings have more potentials to provide energy flexibility to the grid compared to other types of buildings, due to the existing building management, control systems and large energy consumption. Consumers in office buildings （building owners/managers and occupants） take a main role for adopting and engaging in building energy flexibility. This paper provides a systematic review of consumer central energy flexibility in office buildings with the discussion of social, technical and business aspects. This paper clarifies the correlations of consumers＇ concems, external influential factors, energy flexibility resources and technology with eight hypotheses. This paper suggests that technical solutions with the integration of distributed energy resources, building management and control system can boost energy flexibility in the office buildings.

Investigation and analysis on indoor air quality of large commercial office building in summer

To study the indoor air qualities（IAQ）of large commercial office buildings in Hunan province of China and the corresponding improvement methods,the IAQ of a large commercial office building in Changsha in July,2008,is investigated.A questionnaire survey and field tests are used to collect data.According to the data of twelve rooms in this building,objective evaluation and the subjective evaluation of the IAQ are obtained.Almost all of the environmental parameters in these rooms basically meet the standards of the objective evaluation.But the average concentration of carbon dioxide in most rooms cannot reach the value of the cleanliness standards,1 255 mg/m^3.The average acceptability of the IAQ in these rooms is 71%,which is lower than the value of the ASHRAE 55—1992 standards,80%.The proper increase in the wind speed and the indoor fresh air supply can greatly improve the objective evaluation and the subjective evaluation of the IAQ.

Stochastic and Distributed Optimal Energy Management of Active Distribution Networks Within Integrated Office Buildings

This paper proposes a stochastic and distributed optimal energy management approach for active distribution networks(ADNs)within office buildings.The proposed approach aims at scheduling office buildings fitted with heating ventilation and air conditioning(HVAC)systems,and electric vehicle(EV)charging piles,to participate in the ADN optimization.First,an energy management approach for the ADN with aggregated office buildings is proposed.And the ADN optimization model is formulated considering the detailed building thermal dynamics and the mobile behaviors of workers.Then,to consider un-certainties of photovoltaic(PV)power,scenario-based stochastic programming is integrated into the ADN optimization model.To further realize the stochastic energy management of the ADN within office buildings in a distributed manner,the alternating direction method of multipliers(ADMM)is used to solve the ADN optimization model.The original ADN optimization problem is divided into the network-side and the building-side sub-problems to effectively protect the privacy of the ADN and the office buildings.Finally,the ADN optimization model incorporating office buildings is validated in the winter by numerical studies.In addition,the impacts of comfort temperature range and expected state of charge(SOC)at departure are analyzed.Index Terms—ADN,EV,HVAC system,Office building,Stochastic and distributed energy management.

Assessment of the Energy Impact of Using Building Integrated Photovoltaic and Electrochromic Glazing in Office Building in UAE

The aim of this research was to explore the energy benefits and future potential of using Building Integrated Photovoltaic (BIPV) and Electrochromic Glazing (EG) within the climatic conditions of the city of Abu Dhabi. The Integrated Environmental Solutions (IES-VE) energy modeling software was used to assess the energy performance, mainly the reductions in HVAC and lighting, for different configurations and compare that to the base case scenario for south, east, west, and north facing facades. The results showed that the BIPV is most advantageous on the south fa?ade while the EC glazing performs best on the north facing windows. Moreover, the change in sensor location increased the energy savings for both cases, although the change was very marginal compared to the change of the glass properties. Using an automated light control system with dimming for both models, compared against the standard on-off lighting mechanism in the base case, the BIPV proves to have a higher total annual energy saving potential for most orientations, upto 33.5% while dynamic EC was best suited for the North orientation resulting in 7.4% reduction in the total annual energy consumption.

Optimization of Office Building Façades in a Warm Summer Continental Climate

A typical office building model with conventional use and contemporary building systems was developed for fa?ade optimization in continental climate. Wall, glazing area and window parameters were taken as the main variables. The objective function of optimization task described in this article is the minimization of cooling and heating energy con-sumption. The office building fa?ades optimization was carried out using a combination of IDA Indoor Climate and Energy 4.5 and GenOpt. The process is described in detail so that the approach may be emulated. A hybrid multidimen-sional optimization algorithm GPSPSOCCHJ was used in calculation process. The optimization results are presented in four quick selection charts to assist architects, designers and real estate developers make suitable early stage fa?ade selection decisions.

Building International Gateway Offices with ZXJ10

1 GeneralEconomic globalization is resulting inrapid development of the telecommuni-cation industry. It is now necessary formany contries to build new internationalgateway offices or expand their existing sys-tems in order to become interconnected with

Analysis of Solar Direct-Driven Organic Rankine Cycle Powered Vapor Compression Cooling System Combined with Electric Motor for Office Building Air-Conditioning

Solar energy powered organic Rankine cycle vapor compression cycle(ORC-VCC)is a good alternative to convert solar heat into a cooling effect.In this study,an ORC-VCC system driven by solar energy combined with electric motor is proposed to ensure smooth operation under the conditions that solar radiation is unstable and discontinuous,and an office building located in Guangzhou,China is selected as a case study.The results show that beam solar radiation and generation temperature have considerable effects on the system performance.There is an optimal generation temperature at which the system achieves optimum performance.Also,as a key indicator,the cooling power per square meter collector should be considered in the hybrid solar cooling system in design process.Compared to the vapor compression cooling system,the hybrid cooling system can save almost 68.23%of electricity consumption.

An Experimental and Numerical Analysis of Daylighting Performance for an Office Building

The urgency of increasing energy efficiency in new building design and retrofits has pushed lighting simulation to play a central role in sustainable lighting design. The shape of the building and its orientation, the reflectances of building surfaces and glazed areas are important parameters in the daylighting design of buildings. Glazing systems can cut energy consumption and associated pollution sources, reduce peak demand, enhance daylighting performance and improve occupant comfort. This paper presents the results of a numerical and experimental comparison between the performances of an office building with and without external sunscreens. The aim was to analyse the illuminance distribution and some investigations have also been made with regards to the effect on daylight in rooms when sunscreens are used. The experimental results were obtained using an office building scale model and sky simulator. The numerical results were obtained through radiance, the ray-tracing program, to accurately predict the light levels and produce photo realistic images of the architectural space in all sky conditions： Illuminance values were obtained respectively through reference point measurements. The daylighting performances of the office building model with and without the sunscreens have been compared and analysed.

GREEN BUILDING RATING FOR OFFICE BUILDINGS-LESSONS LEARNED

Office buildings constitute a significant proportion of the non-residential building stock.In recent years,various rating tools have been developed to foster green office building development.The Green Building Council of Australia(GBCA)has devel-oped the Green Star-Office rating tools for this purpose.There are an increasing number of stakeholders adopting these tools to showcase their efforts in sustain-able development.This research focuses on the challenges and barriers in obtain-ing GBCA ratings in Australian Office buildings.To accomplish this,the scoring sheets from the rating of 264 certified office buildings were collected and critically analysed.The findings indicated that credits related to the attributes of innovation,ecology and energy are comparatively difficult to achieve.It was also found in this study that a large number of projects did not apply for the specific credits of refrig-erant global warming potential,re-use of façade,topsoil and fill removal from site,and individual comfort control.This study provides a useful reference to both the property developer and the Green Building Council of Australia for green building developments in the future.In particular,the findings provide useful inputs to the development of the next generation of green building rating tools.

ENERGY CONSUMPTION,ENVIRONM ENTAL IMPACTS AND EFFECTIVE MEASURES OF GREEN OFFICE BUILDINGS:ALIFE CYCLE APPROACH

The last few decades have witnessed a rapid development of green buildings in China especially the office sector.The life cycle assessment(LCA)approach has potential to weigh the benefits and costs associated with green building developments.Essentially,the LCA method evaluates the costs and benefits across a building’s life cycle with a system approach.In this study,a green office building in Beijing,China,was analyzed by life cycle assessment to quantify its energy use and evaluate the environmental impacts in each life cycle stage.The environmental impacts can be reduced by 7.3%,1.6%and 0.8%by using 30%gas-fired electricity generation,increasing the summer indoor temperature by 1℃,and switching off office equipment and lighting during lunchtime,respectively.Similarly,by reusing 80%of the selected materials when the building is finally demolished,the three major adverse environmental impacts on human health,ecosystem quality,and resource depletion can be reduced by 11.3%12.7%,and 7.1%respectively.Sensitivity analysis shows that electricity conservation is more effective than materials efficiency in terms of a reduction in environmental impacts.These findings are useful to inform decision makers in different stages of the green building life cycle.

ACOUSTICAL EVALUATION OF SIX‘GREEN’OFFICE BUILDINGS

To explain the reactions of the building occupants to their acoustical environments,meetings with the designers,walk-through surveys,and detailed acoustical measurements were done.The objective was to determine how design decisions affect office acoustical environments,and how to improve the acoustical design of‘green’office buildings.Design-performance criteria were established.Measurements were made of noise level,reverberation time,speechintelligibility index(SII),and noise isolation.Noise levels were atypically low in unoccupied buildings with no mechanical ventilation,but excessive in areas near external walls next to noisy external noise sources—especially with windows open for ventilation—and in occupied buildings.Reverberation times were excessive in areas with large volumes and insufficient sound absorption.Speech intelligibility was generally adequate,but speech privacy was inadequate in shared and open-office areas,and into private offices with the doors open for ventilation.Improvement of the acoustical design of‘green’buildings must include increasing the external-internal noise isolation and that between workplaces,and the use of adequate sound absorption to control reverberation and noise.

Energy Consumption Monitoring Analysis for Residential, Educational and Public Buildings

In the present article thermal and electrical energy consumptions for different types of buildings are analyzed. The latitude and longitude of the researched area are defined 59?00'N and 26?00'E. According to K?ppen climate classification the area is located in warm summer continental climate. The study consist 40 residential, 7 educational and 44 public buildings. Three years data for each building type among 2006-2011 was used. Several detailed energy balances are presented for apartment buildings. In addition the different ways of domestic hot water preparation are analyzed for apartment buildings. The school buildings average consumption values are represented in study. Also valuable information of measured electrical energy consumption balance for a new office building is presented. Finally there is included the energy consumption analysis of public buildings.