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Energy management in existing building services installations is an essential focus of contemporary facilities management. The subway company that is one of the major utilities services in Hong Kong Special Administrative Region has considered better energy management schemes in its subway stations to reduce the running cost. In the past few years some feasible measures in the mechanical ventilation and air conditioning (MVAC) systems were implemented, however the engineering decisions were supported by trial‐and‐error or imprecise estimation. Improvement to this process would be possible if numerical optimization methods were to be used. An evolutionary algorithm coupled with an external plant simulation programme was applied to determine the optimum conditions of the essential parameters of the MVAC systems. For the centralized MVAC systems under study, the developed optimization and simulation model was found useful in appraising the energy management opportunities for effective design and facilities management.

This paper aims to explain the current state of energy consumption and economic development in Beijing's construction industry and identify the relationship between the two systems so as to supply decision support for the future.

This paper presents a design of a coordinated development model based on the theory of synergetics. The focus of the paper is on how to integrate energy consumption indices and economic development indices to determine coordinated development indices in a relevant and useful manner. While analyzing energy composite consumption and economic composite development, respectively, all the variables normalized are eliminated inter‐correlated characteristics by making use of principal component analysis (PCA).

Beijing's construction development is experiencing the transition from economic development hysteresis to energy consumption hysteresis. The higher coordinated development degree is predicting the energy‐economy system is trending to stability in Beijing's construction industry which does not necessarily mean a perfect development trend but an upper limit of the increasing rate in energy consumption. Thus, or at least maintaining the current economic development and energy utilization policy, production specifications, or using new technology, new method and economic policy to stimulate the economic development, or more attention from all the stakeholders being paid to saving more energy than before, will be still priority considerations for Beijing's construction industry in the following years.

The paper proposes an original framework for examining the relationship between energy consumption and economic development in construction industry. The framework is also capable of identifying if the growth rate in energy consumption goes beyond the upper limit.

To critically compare three future weather year (FWY) downscaling approaches, based on the 2009 UK Climate Projections, used for climate change impact and adaptation analysis in building simulation software.

The validity of these FWYs is assessed through dynamic building simulation modelling to project future overheating risk in typical English homes in 2050s and 2080s.

The modelling results show that the variation in overheating projections is far too significant to consider the tested FWY data sets equally suitable for the task.

It is recommended that future research should consider harmonisation of the downscaling approaches so as to generate a unified data set of FWYs to be used for a given location and climate projection. If FWY are to be used in practice, live projects will need viable and reliable FWY on which to base their adaptation decisions. The difference between the data sets tested could potentially lead to different adaptation priorities specifically with regard to time series and adaptation phasing through the life of a building.

The paper investigates the different results derived from FWY application to building simulation. The outcome and implications are important considerations for research and practice involved in FWY data use in building simulation intended for climate change adaptation modelling.

One of the fundamental human requirements is a working environment that allows people to perform their work optimally under comfortable conditions. Given that buildings and air conditioning systems are designed on the basis of a certain level of discomfort, this raises the key question ‘What is the effect of the level of comfort on the productivity of people working in office environments?’ The purpose of this paper is to quantify this relationship as an aid to making choices regarding the working environment at strategic level within the facilities management process, with particular emphasis on thermal conditions.

The Middle Eastern terrain is expected to encounter unprecedented climatic conditions before the turn of the next century (circa. 80 years), emanating from extreme heat waves that exceed the critical threshold of habitable conditions. This threatens to cause a significant challenge that is exacerbated by a gap between the supply and demand of affordable energy. Therefore, the purpose of this study is to investigate the potential of utilising nearly zero-energy buildings (nZEB) to improve the performance of residential buildings in Iraq and the Middle East.

This study uses Iraq as a case-study because of the breadth of climatic conditions experienced across its wide-reaching territory and also because of the recent critical infrastructural challenges following the geo-political crisis. Three virtual buildings were simulated for Baghdad, Mosul and Basra cities to narrow the confines of the region to achieve nZEB under current and future climatic weather scenarios.

The findings showed that in all three cases studies, the buildings located within the three climatic regions in Iraq could achieve both significant annual energy reductions as well as nZEB standards which could range from 41 per cent to 87 per cent for current climatic conditions and 40 per cent to 84 per cent by 2080. An analysis has also been carried out for the three case-study cities which revealed significant operational-cost savings achievable through nZEB buildings.

There are currently limited studies that investigate such positive potential for nZEB strategies under the current and predicted future climatic scenarios in the Middle East.

This paper aims to develop a forecasting tool for the automatic assessment of both environmental and economic benefits resulting from low-carbon investments in the real estate sector, especially when applied in large building stocks. A set of four artificial neural networks (NNs) is created to provide a fast and reliable estimate of the energy consumption in buildings due to heating, hot water, cooling and electricity, depending on some specific buildings’ characteristics, such as geometry, orientation, climate or technologies.

The assessment of the building’s energy demand is performed comparing the as-is status (pre-retrofit) against the design option (post-retrofit). The authors associate with the retrofit investment the energy saved per year, and the net monetary saving obtained over the whole cost after a predetermined timeframe. The authors used a NN approach, which is able to forecast the buildings’ energy demand due to heating, hot water, cooling and electricity, both in the as-is and in the design stages. The design stage is the result of a multiple attribute optimization process.

The approach here developed offers the opportunity to manage energy retrofit interventions on wide property portfolios, where it is necessary to handle simultaneously a large number of buildings without it being technically feasible to achieve a very detailed level of analysis for every property of a large portfolio.

Among the major accomplishments of this research, there is the creation of a methodology that is not excessively data demanding: the collection of data for building energy simulations is, in fact, extremely time-consuming and expensive, and this NN model may help in overcoming this problem. Another important result achieved in this study is the flexibility of the model developed. The case study the authors analysed was referred to one specific stock, but the results obtained have a more widespread importance because it ends up being only a matter of input-data entering, while the model is perfectly exportable in other contexts.

In hot and dry climates, air conditioning accounts for a large portion of total energy consumption; therefore, this paper aims to investigate the impact of sol-air temperature and ground temperature on the loss of cooling energy in hot and dry regions of Iran.

In line with this objective, the values of sol-air temperature along different directions and ground temperature at different depths were assessed with respect to climatic data of Yazd City. The impact of sol-air temperature and ground temperature on the rate of heat loss was investigated. So, energy loss of the walls aligned to four primary directions was calculated. This process was repeated for a 36 m² building with three different shape factors. All analyses were conducted for the period from May to September, during which buildings need to be cooled by air conditioners.

Numerical analyses conducted for hot and dry climate show that sol-air temperature leads to a 41-17 per cent increase in the wall’s energy loss compared with ambient temperature. Meanwhile, building the wall below the surface leads to a significant reduction in energy loss. For example, building the wall 400 cm below the surface leads to about 74.8-79.2 per cent energy saving compared with above ground design. The results also show that increasing the direct contact between soil and building envelope decreases the energy loss, so energy loss of a building that is built 400 cm below the surface is 53.7-55.3 per cent lower than that of a building built above the surface.

The impact of sol-air temperature and ground temperature on the cooling energy loss of a building in hot and dry climate was investigated. Numerical analysis shows that solar radiation increases heat loss from building envelope. Soil temperature fluctuations decrease with depth. Heat loss from building envelope in an underground building is lower than that from building envelope in a building built above the ground. Three different shape factors showed that sol-air temperature has the maximum impact on square-shaped plan and minimal impact on buildings with east-west orientation.

The operation of chiller systems could account for considerable electricity consumption in air‐conditioned buildings in subtropical regions. The purpose of this paper is to consider using data envelopment analysis (DEA) to facilitate management of their energy performance.

A system serving an institutional building was studied, which contains five sets of chillers, pumps and cooling towers. The building has a total floor area of about 25,000m² and comprises classrooms, lecture theatres, offices and laboratories. The scale, technical and overall efficiencies defined in DEA were calculated based on the correlation between the output variable – system coefficient of performance (COP) – and the input variables – load factor and temperatures of chilled water and condenser water. The efficiencies were further examined to explain how outside air temperatures and controllable variables affect the system performance.

The paper reveals that existing energy management gives a technical efficiency of 0.85 and fine‐tuning the temperature‐related variables could achieve an electricity saving of 14.8 per cent.

The improved COP predicted by DEA is related only to fine‐tuning of the input variables concerned. An increase of COP by other advanced controls or system upgrades should be assessed based on robust system modelling techniques. Yet the extent of COP improvements helps investigate energy management opportunities requiring no or insignificant capital investment on existing systems.

A systematic approach to performing energy management of a chiller system is proposed. The DEA helps examine which operating variable should be fine‐tuned to achieve the highest possible performance.

It is an under researched area to consider using scale and technical efficiencies in DEA to explain energy management of chiller systems and to estimate the highest achievable performance.

The two main contributing factors that control the overall buildings’ energy performance are the heating ventilation and air conditioning (HVAC) system and the envelope design. Environmental design guidelines that consider these two factors aim to lower energy consumption. However, they are regional and climate-sensitive. This study aims to investigate how three main buildings’ envelope design variables (orientation, compactness and window to wall ratio) impact the overall building’s energy consumption within Kuwait’s regional and climate conditions.

This study simulate the energy consumption of typically shaped buildings by varying their geometry between a square to a rectangular floor plan. This study analyse the associated energy usage and provide early-stage envelope design guidance specific to the country’s conditions, to make informed decisions towards environmentally conscious buildings.

The analysed envelope variables have the potential to reduce energy consumption by 40%, and the possibility to reduce HVAC system capacity by 30%. In contrast to the general guidance in literature and standards, the simulation results demonstrate that less compact building forms perform on occasions better than the most compact ones.

The objective of this paper is to quantify the energy consumption rates for buildings located within the Arabian Peninsula, an under-studied region with potentially high interest considering three main envelope design variables. The buildings’ yearly energy consumption patterns are unique and suggest different envelope design considerations, compared to other regions with different climate conditions. This emphasises the importance of regional guidelines for the different factors associated with energy and buildings’ environmental performance.

The purpose of this paper is to establish how UK offices and double skin façade (DSF) technologies can be best matched for refurbishment purposes.

This research uses a mixed methodology including primary and secondary data collection, analysis and interpolation through document analysis, comprehensive critical literature review, and case study approach.

In total, 22 benchmarks have been developed to represent 75 per cent of the existing office stock in the UK. Through a comparison with 36 case studies of European buildings refurbished with DSFs, two benchmarks showed to be most suitable for a DSF refurbishment and most appropriate configurations for a successful DSF refurbishment have been identified. Findings have been also checked against a large sample of DSF buildings in the UK.

The benchmarks delivered in this study can be developed further into parametric models, where variations can be obtained by changing the parameters provided. A follow-up study can be designed to help define the exact share of existing stock represented by each benchmark and to foster research where a more typological or statistical approach might be intended.

Findings from this research can be of practical use to academics and practitioners alike involved in research related to office refurbishments, DSFs, and the UK existing office stock. The design for this research can also be adapted to similar studies on its own or further developed to suit different contexts.

Improvements to existing buildings can preserve established communities, with a clear social advantage.

This paper represents the first attempt to systemically shed light on how existing UK offices and DSF technologies can be best matched in refurbishments. The benchmarks developed, the DSF case studies, and guidelines for suitable DSF technologies in UK office refurbishments represent the original contribution of this research.