Bio: Sivakumar Palaniappan is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Embodied energy & Cement. The author has an hindex of 9, co-authored 20 publications receiving 253 citations. Previous affiliations of Sivakumar Palaniappan include Arizona State University & San Diego State University.
TL;DR: In this article, a case study on life cycle energy analysis of a residential development consisting of 96 identical apartment-type homes located in Southern India is presented, where energy use due to transportation of materials and construction equipment use at site are quantified.
Abstract: The life cycle energy of a building consists of construction energy, operational energy and demolition energy. Construction refers to initial construction as well as recurring maintenance and repair work. Initial construction represents manufacturing of construction materials, transportation and site related on-site construction processes. Only a few studies focused on life cycle energy use of Indian residential buildings. However, the energy use due to on-site construction processes is either ignored or not modelled with adequate level of detail at present. This paper presents a case study on life cycle energy analysis of a residential development consisting of 96 identical apartment-type homes located in Southern India. Energy use due to transportation of materials and construction equipment use at site are quantified. Sensitivity analysis is carried out to study the influence of building service life and monthly electricity use per home on the relative significance of construction energy and operational energy. The construction energy is found to be a significant component of life cycle energy of residential buildings with partial or no air-conditioning. Further, reduced building service life period and increased energy efficiency achieved in the operational phase makes the construction energy as important as the operational energy with respect to life cycle.
TL;DR: In this paper, the authors proposed a framework for sustainability assessment, in terms of the CO2 emissions and energy demand, that can be adopted in cases where suitable databases are not readily available.
Abstract: The consumption of cement in India and other emerging economies is expected to increase because of the continuing push towards development of housing and infrastructure. The increasing production of cement and utilization of concrete are bound to have a major impact on sustainability. The present work proposes a framework for sustainability assessment, in terms of the CO2 emissions and energy demand, that can be adopted in cases where suitable databases are not readily available. Case studies for cement manufacture have been considered in South India, with different system boundaries such as ground-to-gate, gate-to-gate and CSI. The assessment made using data from the plant and other sources highlights the benefits of using supplementary cementitious materials (SCMs) in terms of reducing the impact of cement and concrete. More importantly, limestone calcined clay cement shows considerable promise in terms of reduction in CO2 emissions and energy demand in both cement and concrete, with more improvement in higher grade concrete.
TL;DR: In this article, the authors presented a comprehensive comparison of credit structure and indicators of ten green building rating schemes that are widely used in North America, Europe and Asia, including Green Globes, LEED USA, BREEAM, DGNB system, GRIHA, IGBC system, BEAM Plus, Green Mark, CASBEE and Green Star are considered.
Abstract: Green building rating schemes are used in industry practice as a practical tool for sustainable development. Green building ratings facilitate conservation of natural resources and reduction in environmental impacts while satisfying the user requirements. The credit structure, indicators, level of certification, priorities allocated to environmental, economic and social aspects of sustainable development vary widely among the green building schemes used in different countries. This study presents a comprehensive comparison of credit structure and indicators of ten green building rating schemes that are widely used in North America, Europe and Asia. Green building schemes namely Green Globes, LEED USA, BREEAM, DGNB system, GRIHA, IGBC system, BEAM Plus, Green Mark, CASBEE and Green Star are considered. The comparison is performed at six different levels. The extent to which the sustainable development objectives are met in these schemes is evaluated. Further, this study examines the credit structuring of the two Indian green building schemes – GRIHA and the IGBC system, identifies the areas of improvement and proposes a framework for the next-generation green building scheme that could be adopted in India. The findings of this study are beneficial to improve the effectiveness of green building rating schemes in India.
TL;DR: In this paper, the influence of technological, operational and site related parameters on the performance of earthmoving operations using five case studies is presented, and a procedure for incorporating sustainability metrics into earth moving operations during the planning phase is presented.
Abstract: The building life cycle consists of production, on-site construction, operation and demolition phases. The energy use due to construction (i.e. materials and on-site construction) represents a significant component of life cycle energy in case of naturally ventilated or partially air-conditioned buildings. Earthmoving is one of the major parts of construction processes and it involves the use of heavy equipment. This study presents the influence of technological, operational and site related parameters on the performance of earthmoving operations using five case studies. The energy use due to ‘excavation’ and ‘excavation and transport of soil’ is in the range of 14–89 MJ/cu.m. and 19–135 MJ/cu.m. respectively. The choice of equipment selection and its influence on the time (duration), cost, energy use and emissions of earthmoving operations are presented using trade-off analysis. It is observed that the cost of transporting soil could be higher than the excavation cost if the truck is not utilized effectively. A procedure for incorporating sustainability metrics into earthmoving operations during the planning phase is presented. The practical application of this work in industry practice is also demonstrated. The findings are expected to be useful for construction planners in decision making including sustainability metrics.
TL;DR: In this article, the authors present a process-wise evaluation of energy use and CO2 emissions for clinker, Ordinary Portland Cement (OPC), and Portland Pozzolana Cement(PPC) using the principles of life-cycle assessment.
Abstract: Cement is one of the most widely used materials in construction. This study presents a process-wise evaluation of energy use and CO2 emissions for clinker, Ordinary Portland Cement (OPC) and Portland Pozzolana Cement (PPC) using the principles of life-cycle assessment. Two cement plants located in India are considered as typical case studies. The gate-to-gate system boundary condition is considered. The energy use for clinker is found to be 3990 and 3626 MJ/ton for case studies 1 and 2, respectively. The associated CO2 emissions for clinker are 849 and 868 kg CO2/ton. The energy use for OPC is 4015 and 3821 MJ/ton for case studies 1 and 2, respectively. The related CO2 emissions are 802 and 855 kg CO2/ton. The energy use for PPC is 3077 and 2733 MJ/ton for case studies 1 and 2, respectively. The associated CO2 emissions are 606 and 595 kg CO2/ton. It is observed that the energy use and CO2 emission of PPC are at least 20% less compared to OPC. The results are compared with five geographical regions across the world.
TL;DR: In this article, a review on three streams of life cycle studies that have been frequently applied to evaluate the environmental impacts of building construction with a major focus on whether they can be used for decision making is provided.
Abstract: This paper provides a review on three streams of life cycle studies that have been frequently applied to evaluate the environmental impacts of building construction with a major focus on whether they can be used for decision making. The three streams are Life Cycle Assessment (LCA), Life Cycle Energy Assessment (LCEA) and Life Cycle Carbon Emissions Assessment (LCCO2A). They were compared against their evaluation objectives, methodologies, and findings. Although they share similar objectives in evaluating the environmental impacts over the life cycle of building construction, they show some differences in the major focuses of evaluation and methodologies employed. Generally, it has been revealed that quite consistent results can be derived from the three streams with regard to the relative contribution of different phases of life cycle. However, discrepancies occur among the findings obtained from the three streams when different compositions of fuel mixes are used in power generation, or when the overall impacts are not contributed mostly by greenhouse gases emissions. The use of different functional units in different studies also makes it difficult to compare results with benchmarks or results from previous studies. Besides, there are drawbacks in boundary scoping, methodology framework, data inventory and practices which impair their usefulness as a decision making support tool for sustainable building designs.
01 Jan 2011
TL;DR: In this paper, the authors present results obtained from monitoring a 1.72kWp photovoltaic system installed on a flat roof of a 12m high building in Dublin, Ireland (latitude 53.4°N and longitude 6.3°E).
Abstract: This paper presents results obtained from monitoring a 1.72 kWp photovoltaic system installed on a flat roof of a 12 m high building in Dublin, Ireland (latitude 53.4°N and longitude 6.3°E). The system was monitored between November 2008 and October 2009 and all the electricity generated was fed into the low voltage supply to the building. Monthly average daily and annual performance parameters of the PV system evaluated include: final yield, reference yield, array yield, system losses, array capture losses, cell temperature losses, PV module efficiency, system efficiency, inverter efficiency, performance ratio and capacity factor. The maximum solar radiation, ambient temperature and PV module temperature recorded were 1241 W/m2 in March, 29.5 °C and 46.9 °C in June respectively. The annual total energy generated was 885.1 kW h/kWp while the annual average daily final yield, reference yield and array yield were 2.41 kW h/kWp/day, 2.85 kW h/kWp/day and 2.62 kW h/kWp/day respectively. The annual average daily PV module efficiency, system efficiency and inverter efficiency were 14.9%, 12.6% and 89.2% respectively while the annual average daily performance ratio and capacity factor were 81.5% and 10.1% respectively. The annual average daily system losses, capture losses and cell temperature losses were 0.23 h/day, 0.22 h/day and 0.00 h/day respectively. Comparison of this system with other systems in different locations showed that the system had the highest annual average daily PV module efficiency, system efficiency and performance ratio of 14.9%, 12.6% and 81.5% respectively. The PV system’s annual average daily final yield of 2.4 kW h/kWp/day is higher than those reported in Germany, Poland and Northern Ireland. It is comparable to results from some parts of Spain but it is lower than the reported yields in most parts of Italy and Spain. Despite low insolation levels, high average wind speeds and low ambient temperature improve Ireland’s suitability.
TL;DR: In this article, the authors presented data on the chloride diffusion coefficient (Dcl), ageing coefficient (m) and chloride threshold (Clth) related to seven concrete mixes (four M35 and three M50) with OPC, OPC+PFA (pulverised fuel ash) and limestone-calcined clay cement (LC3).
Abstract: This paper presents data on the chloride diffusion coefficient (Dcl), ageing coefficient (m) and chloride threshold (Clth) related to seven concrete mixes (four M35 and three M50) with OPC, OPC + PFA (pulverised fuel ash) and limestone-calcined clay cement (LC3). Using these, the service lives of a typical bridge pier and girder with the PFA and LC3 concrete were found to be much higher than those with OPC concrete of similar strength. From life-cycle assessment, the CO2 footprint of PFA and LC3 concrete were found to be significantly lower than those of OPC concrete of similar strength. Further, the CO2 emissions per unit of concrete per year of estimated service life, as a combined indicator of service life and carbon footprint, are similar for concrete with PFA and LC3, which are much lower than that with OPC.
TL;DR: A review of the literature available on the subject of the recently developed limestone calcined clay cement (LC3) can be found in this article, where an introduction to the background leading to the development of LC3 is discussed.
Abstract: This article reviews the rapidly developing state-of-the-art literature available on the subject of the recently developed limestone calcined clay cement (LC3). An introduction to the background leading to the development of LC3 is first discussed. The chemistry of LC3 hydration and its production are detailed. The influence of the properties of the raw materials and production conditions are discussed. The mixture design of concrete using LC3 and the mechanical and durability properties of LC3 cement and concrete are then compared with other cements. At the end the economic and environmental aspects of the production and use of LC3 are discussed. The paper ends with suggestions on subjects on which further research is required.
TL;DR: In this article, a review summarises literature to examine the transition from portland limestone cement system to composite ternary binder systems involving limestone and the interaction of fine limestone is classified and elaborated under two broad umbrellas: physical and chemical interactions.
Abstract: The review summarises literature to examine the transition from portland limestone cement system to composite ternary binder systems involving limestone. Interest in limestone addition as an ideal component in multicomponent binder systems has surged as evident from the large volume of literature published in the recent past. A ternary blended system, with co-substitution of limestone, has the potential to complement the reaction of the supplementary cementitious materials (SCMs). The direct addition of limestone powder helps to attain higher substitution levels of portland cement clinker, improve early age properties, and supplement SCM's reactivity. However, the dilution of hydrates could hamper the long-term benefits. In this review, the interaction of fine limestone is classified and elaborated under two broad umbrellas: physical and chemical interactions. The physical interactions can manifest in three ways, namely, filler action, shearing action and improved packing, which alters reaction rate and extent at early ages. The chemical interactions also modify the reaction kinetics and phase assemblage due to nucleation of C-S-H on calcite surfaces, preservation of the ettringite phase and formation of carboaluminates. Two different forms of carboaluminate hydrates — hemicarboaluminate and mono-carboaluminate can be present in the hydrate matrix depending on the balance between carbonate ions and aluminates in the pore solution. Several factors such as replacement level, particle size, choice of SCM, its reactivity and reactive aluminates content, sulphate levels, curing temperature, and duration of curing can control the carboaluminate formation, reaction degree of SCMs and chemical interaction from limestone additions. A combination of physical and chemical effects makes fine limestone a potential material for co-substitution with aluminosilicate based SCMs, mainly fly ash, slag, and calcined clay. In this review, the factors affecting limestone-SCM composites are summarised based on a detailed literature survey. The effects of SCM-limestone cement composites on hydration kinetics, reaction chemistry, the reactivity of SCMs, the stability of hydrated phases, and contribution to the physical structure development and macroscopic properties by evaluating hydration and mechanical properties are discussed. The importance of AFm (Al2O3–Fe2O3-mono) phases in various deterioration mechanisms in concrete and their influence on performance characteristics in different exposure environment is critically appraised.