Towards Near Zero Energy Home

In the context of building design, as investment in the built-environment continues to grow, the requirement to deliver low-energy buildings will become ever more pressing as natural resources dwindle and consumer energy costs increase. Energy efficiency awareness and regulations continue to rise in the Gulf Cooperation Council (GCC) countries but the majority of building stock of which the larger share in energy consumption has not been designed for energy efficiency. The design and construction of buildings in hot humid climates require high-energy consumption typically for air conditioning due to higher thermal loads. Regionally, there is a rising concern on the current rate of energy consumption due to air conditioning. The global sustainability assessment system (GSAS), a performance-based system raised the bar of efficient design by the development of stringent energy passive design benchmarks on the thermal cooling need in buildings. This chapter introduces the simulation measures undertaken to reduce the cooling need using a ‘showcase’ house or the ‘near Zero Energy Home’ (nZEH), which is currently under construction. The chapter presents and discusses the Be Lean, Be Clean and Be Green strategies that used to reduce the cooling demand by more than 80% and the overall energy consumption by 75%

QGreen Low-Carbon Technology: Cooling Greenhouses and Barns Using Geothermal Energy and Seawater Bittern Desiccant

In hot-humid climates, cooling greenhouses and barns are needed to protect crops from extremely high temperature and to ensure high-yielding dairy cows. In Qatar, outside air temperature exceeds 46°C during summer, and the wet-bulb temperature can exceed 30°C which makes greenhouses and barns unworkable during this season. This study provides theoretical and experimental data for cooling greenhouses and barns using highly efficient and low-carbon technology (QGreen). QGreen uses groundwater (geothermal) for indirect-direct evaporative cooling coupled with desiccant dehumidification. The desiccant used is seawater bittern which is a by-product of the desalination process. A desiccant indirect-direct evaporative cooling panel system is designed and analyzed. The results show that the use of groundwater will enhance the efficiency and reduce the wet-bulb temperature dramatically. As a result, the efficiency of the overall cooling system is enhanced by more than 50% compared to the direct evaporative cooling efficiency that was recorded

Improving Building Fabric Energy Efficiency in Hot-Humid Climates using Dynamic Insulation

Peer reviewedPostprin

Post Covid 19: An Innovative System to Supply 100% Treated Fresh Air for Improving City Liveability

Prior to COVID-19, densely occupied areas were already suspected of making employees sick. Post-COVID-19, there is an urgent need to improve air quality and ventilation standards shall change. However, any changes to ventilation must consider other negative consequences including energy and health and well-being impacts from thermal discomfort and exposure to pollutants. The need for moving away from traditional energy sources and to find alternate energy sources is undoubtedly one of the primary objectives for a sustainable progress to humankind. The design and construction of buildings in hot-humid climates requires high energy consumption typically for air conditioning due to higher thermal loads. A further increase in ventilation rates will have intensive impact in energy consumption and infrastructure loads. This chapter presents the performance of an innovative fully integrated smart ventilation system with low energy consumption. It is all in one ventilating and air conditioning system that provides efficient, cost-effective, and sustainable cooled fresh air for open or enclosed spaces whilst achieving thermal comfort. Based on the application, it consists of multistages that can dehumidify and cool the air to the required comfort level. The system has shown 50–60% reduction in energy consumption compared with conventional systems

Solar Pond Driven Air Conditioning Using Seawater Bitterns and MgCl₂ as the Desiccant Source

Solar energy is used for a wide range of applications such as electricity production, desalination, cooling, heating, etc. Solar-based technologies are widely spread and increasingly studied in the industry. This theoretical and experimental study focuses on solar ponds as a desiccant and low-grade energy source. A thermal model has been developed for a salinity gradient solar pond (SGSP) with a non-convective zone split into 10 sub-zones. A solar pond was constructed and used as a case study for the validation of the predictive model capabilities. The dimensional characteristics of the pond, as well as the solar radiation intensity and ambient temperature data obtained from the meteorological data, were used to produce the solar pond’s zone thermal behaviour data. With regards to the thermal behaviour measurements obtained from the solar pond, the predicted data were found to be higher. There is a significant difference between the real-world and meteorological data obtained, the difference between the predicted and real-world pond temperature data was also attributed to the fact that the actual absorbed solar radiation was reduced due to wall shading effect, turbidity and insufficient duration of operation of the pond. In the following year, the stored heat from the previous summer would be expected to improve thermal storage values obtained partially

Solar pond powered liquid desiccant evaporative cooling

Liquid desiccant cooling systems (LDCS) are energy efficient means of providing cooling, especially when powered by low-grade thermal sources. In this paper, the underlying principles of operation of desiccant cooling systems are examined, and the main components (dehumidifier, evaporative cooler and regenerator) of the LDCS are reviewed. The evaporative cooler can take the form of direct, indirect or semi-indirect. Relative to the direct type, the indirect type is generally less effective. Nonetheless, a certain variant of the indirect type - namely dew-point evaporative cooler - is found to be the most effective amongst all. The dehumidifier and the regenerator can be of the same type of equipment: packed tower and falling film are popular choices, especially when fitted with an internal heat exchanger. The energy requirement of the regenerator can be supplied from solar thermal collectors, of which a solar pond is an interesting option especially when a large scale or storage capability is desired

Occupant productivity and office indoor environment quality : a review of the literature

The purpose of this paper is to review the existing literature to draw an understanding of the relationship between indoor environmental quality and occupant productivity in an office environment. The study reviews over 300 papers from 67 journals, conference articles and books focusing on indoor environment, occupant comfort, productivity and green buildings. It limits its focus to the physical aspects of an office environment. The literature outlines eight Indoor Environmental Quality (IEQ) factors that influence occupant productivity in an office environment. It also discusses different physical parameters under each of the IEQ factors. It proposes a conceptual model of different factors affecting occupant productivity. The study also presents a review of the data collection methods utilised by the research studies that aim to investigate the relationship between IEQ and occupant productivity. The study presents a comprehensive discussion and analysis of different IEQ factors that affect occupant productivity. The paper provides a concise starting point for future researchers interested in the area of indoor environmental quality

A Novel Integrated Building Energy System for High Performance Façade

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

Climate Change Mitigation through Energy Benchmarking in the GCC Green Buildings Codes

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