• Energy Research

AbstractIndoor environmental quality (IEQ) and its effect on occupant well-being and comfort is an important area of study. This paper presents a state of the art study through extensive review of the literature, by establishing links between IEQs and occupant well-being and comfort. A range of issues such as sick building syndrome, indoor air quality thermal comfort, visual comfort and acoustic comfort are considered in this paper. The complexity of the relationship between occupant comfort and well-being parameters with IEQ are further exacerbated due to relationships that these parameters have with each other as well. Based on the review of literature in these areas it is established that design of buildings needs to consider occupant well-being parameters right at the beginning. Some good practices in all these different areas have also been highlighted and documented in this paper. The knowledge established as part of this paper would be helpful for researchers, designer, engineers and facilities maintenance engineers. This paper will also be of great benefit to researchers who endeavour to undertake research in this area and could act as a good starting point for them.

Abstract Purpose The purpose of the paper is to establish links between Indoor Environment Quality (IEQ) factors that affect occupant productivity and Global Sustainability Assessment System (GSAS) building rating system. The paper analyses the current state of GSAS using a desktop study, survey and brainstorming session organised in a workshop with GSAS Certified Green Professionals (CGP). Methodology/design/approach The study was conducted in three steps. First, a comprehensive literature review was conducted to identify IEQ factors that influence occupant productivity in offices. The second step was a desktop analysis of current GSAS building rating system to identify criteria and submittals that may help to increase occupant productivity. It was followed by a facilitated workshop of GSAS CGPs that included a survey and a brainstorming session to highlight the current state of GSAS rated building performances on occupant productivity. The workshop was attended by 41 CGPs in Doha, Qatar. Findings The paper highlighted that GSAS needs to be updated to increase occupant productivity in GSAS rated buildings. A periodic post-occupancy survey in GSAS buildings should be mandated to ensure better occupant productivity. The paper also presented various methods to make GSAS rated buildings more occupant-friendly. Originality/value This study is the first study to analyse green building guidelines in the context of occupant productivity, especially in Qatar.

AbstractQatar National Development Strategy (QNDS 2011-2016) stated that residential cooling loads count for two-thirds of the energy consumption. The extreme high air-conditioning loads raise the urgent need for novel and multifunctional technologies that reduce the thermal energy demand. The Global Sustainability Assessment System (GSAS) mandated thermal energy benchmarks to reduce the building's need for cooling. The most predominant impact on cooling loads is the solar radiation. Reflecting or reuse of solar radiation has attracted the attention of several researchers. This paper focuses on void space thermal insulation (VSTI) that functions to deliver high performance active and / or passive thermal insulation performance in buildings in tandem with managed fresh air ventilation supply for clean, healthy indoor environments. VSTI can combine the heat losses with the HVAC systems for better building performance. Different embodiments of the VSTI will include brick-block and steel frame constrictions, sandwich panels for pre-cast concrete constructions, internal wall insulation and external wall insulation. Initial modelling results showed that a VSTI panel can potentially deliver the desired level of fabric performance, using only 50% of the insulation thickness irrespective of what insulation material is used. In this paper, a dynamic simulation model was used to estimate the energy and carbon reduction due to the use of VSTI for a residential room. The results showed around 12% reduction in the cooling load and 4% in the overall energy consumption and carbon emissions.

In this investigation, a desiccant dehumidifier is tested for different ranges of liquid to air flow rate ratios to expand the validity range of the results. Theoretical and experimental studies of the simultaneous heat and mass transfer to evaluate the moisture removal rate are conducted. The model predictions are compared with experimental results with very good agreement. Through the experimental study, the important design variables that affect the moisture removal rate are defined and compared with previous studies. The correlation found in the literature is assessed, and the errors are reported. The parameters that are varied during the experiments included the air and liquid flow rates, the air humidity ratio, the desiccant equilibrium humidity and the packing height. It is found that the liquid flow rate has no significant effect on the moisture removal rate when the liquid to air flow ratio has exceeded the value of 2.

AbstractCurrent building regulations enforce building designers towards efficient system design and provision of alternative means of supplying energy. Different green building certification schemes are deployed worldwide to encourage creating a sustainable built environment and the adoption of green building best practices.Micro-generation technologies, low and zero carbon, are either recommended by designers or mandated. A range of constraints including design and technical issues, are currently affecting the wide-scale deployment of micro-generation. For instance, it is important that the micro-generation plant operates for as many hours as possible as an idle plant accrues no benefits. Such issues make the design of a micro-cogeneration technology not quite as straightforward. Combined Heat and Power (CHP) or micro-cogeneration provides means of electricity and heat supply.This paper investigates, through a detailed study, the maximum CO2 reduction that could be achieved by CHP and biomass technologies in a mixed-use development. The implementation of micro-cogeneration, its combination with district heating and the integration of CHP into a trigeneration scheme are investigated. The coupling of CHP unit with absorption cooling, as well as the interactions with biomass boilers, to allow for setting up multi-generation systems for combined local production of different energy vectors are assessed and optimised for maximum CO2 reduction.

New effective technologies and materials that have the potential to reduce energy demand with excellent energy efficiency and low environmental impact are urgently required in the Gulf Region. Dynamic insulation, which functions by recycling fabric heat loss back to the building, has been established theoretically and proven in pilot projects. It sets the green, low carbon benchmark for thermal insulation in buildings. This paper presents details of the Eco-Villa, its construction, how the performance of the villa was monitored, and the findings from the initial monitoring phase and the dynamic simulation model (DSM). The villa was tested in two modes, bypass (static) and dynamic. The static U value of the external envelop wall was estimated at 0.24 W/(m2·K) in bypass mode. The theoretical dynamic U value changed from 0.24 to 0.05 W/(m2·K) when the ventilation airflow was varied from 0 to 0.001 m3/(s·m2) (0 to 1 L/(s·m2)), with a further small reduction occurring when the flow rate increased beyond 0.001 m3/(s·m2) (1 L/(s·m2)). The design ventilation rate for the Eco-Villa was 0.0008 m3/(s·m2) (0.8 L/(s·m2)), which yielded a theoretical dynamic U value of 0.063 W/(m2·K) compared to a measured U value of 0.125 W/(m2·K). The reduction in the fabric conduction gain was found to be 41% whereas the estimate from the DSM was 38%. The results demonstrate the fabric energy efficiency improvements that can be achieved through the use of dynamic insulation.

It is well known that the Gulf Cooperation Council (GCC) of countries resides at or close to the top of the global table of CO2 emissions per capita and its economy relies heavily on its fossil fuels. This provides a context for green building programs that initially aim to create an understanding of emission pathways within the GCC and hence develop approaches to their reduction in the built environment. A set of criteria will allow specific analysis to be undertaken linked to the spatial dimensions of the sector under study. In this paper, approaches to modelling energy consumption and CO2 emissions are presented. As investment in the built environment continues, natural resources dwindle and the cost of energy increases, delivering low-energy buildings will become mandatory. In this study, a hybrid modelling approach (bottom-top & top-bottom) is presented. Energy benchmarks are developed for different buildings’ uses and compared with international standards. The main goals are to establish design benchmarks and develop a modelling tool that contains specific information for all buildings types (existing and new), as well as planned and projected growths within the various city districts, then integrate this database within a geospatial information system that will allow us to answer a range of “what-if”-type questions about various intervention strategies, emissions savings, and acceptability of pre-defined course of actions in the city sector under consideration. The spatial carbon intensity may be adjusted over a certain period, (e.g., through local generation (microgeneration)) or due to an increasing proportion of lower carbon-energy in the generation mix and this can be related to the sector and city overall consumption.