Levels Of Thermal Insulation Research Articles

Energy Efficient Retrofit and Life Cycle Assessment of an Apartment Building

While new buildings should be designed as intelligent low or zero-energy buildings, refurbishment of the existing building stock may present even a greater challenge, when in particular financing of the necessary investments to energy saving measures poses the biggest barrier. As the residential sector in the EU is responsible for about 40% of the total energy consumption and up to 40% of the total carbon dioxide emissions, the residential building stock offers high potential for energy savings. By applying the life cycle assessment, it is possible to optimise the social, economic and environmental aspects, starting from the extraction of raw materials, up to the final disposal of waste materials.A case study of a selected representative residential building located in Slovakia is presented, for which the cost-optimal levels of energy performance are determined in terms of life-cycle costs of the building. Three variants of renovation were defined, each variant having different level of thermal insulation of building constructions. The method of Life-Cycle Costs was used to evaluate the economic feasibility of the suggested renovation scenarios for the apartment house.

OPTIMUM INSULATION THICKNESS FOR BUILDING ENVELOPE- A REVIEW

Through this paper an important issue that what should be the level of insulation for energy conservation in conditioned building envelope is being address. It is well established from the earlier studies of heat transfer across the composite walls that as insulation thickness increases the corresponding resistance to heat flow increases so the rate of heat transfer decreases. The corresponding cost of maintain temperature through artificial means decreases but this is achieve at the cost of insulation which also increases as its thickness increases. The thickness of insulation where total cost of heating/ cooling and insulation cost over the life time becomes minimum is known as optimum insulation thickness. Answer to this question of thermal insulation level in the building envelope components like external wall or roof from economy point of view is being reviewed. Different angles of research in this field being discuss like methods of analyzing annual heating/ cooling loads, insulation material point of view, effect of climate, effect of energy source on optimum insulation thickness. Further different methods used for determination of optimum insulation thickness being reviewed. The effect of solar radiation on optimum insulation thickness is an area which needs further research in Indian context. There is a great need of not only insulating building envelope components like external wall or roof but from economical point of view there is a need to optimize insulation thickness. Further there is need to analyze two insulation materials in combination for maximizing savings.

A multi-criteria methodology for comparing the energy and environmental behavior of cool, green and traditional roofs

The reduction of energy demand for space cooling, as well as the mitigation of the Urban Heat Island effect (UHI), require adequate solutions at building and urban scale. In particular, the roofs of buildings have been identified as a possible field of intervention that could contribute to provide significant energy savings and environmental benefits. In this context, cool and green roofs are two very interesting solutions, which may allow obtaining both the reduction of the energy consumption and the improvement of the comfort sensation in the outdoor and indoor environment.This paper presents a numerical comparative analysis of the energy and environmental performance of three typologies of roof, namely a standard roof (SR), a cool roof (CR) and a green roof (GR). This analysis, developed through dynamic energy simulations under temperate climate, highlights the different thermal behavior for the investigated roof scenarios, also as a function of the level of thermal insulation. Moreover, with the aim to obtain a classification between SR, CR and GR in Mediterranean climate, a scoring system is presented, which considers the whole performance of the investigated roof scenarios under a broad perspective.As a result, it is found that green and cool roofs provide higher energy savings and environmental benefits than highly insulated standard roofs. In particular, scarcely insulated green roofs showed the best performance in relation to the UHI mitigation under the climatic conditions typical of the Mediterranean area.

Vacuum Insulation Panels: Analysis of the Thermal Performance of Both Single Panel and Multilayer Boards

The requirements for improvement in the energy efficiency of buildings, mandatory in many EU countries, entail a high level of thermal insulation of the building envelope. In recent years, super-insulation materials with very low thermal conductivity have been developed. These materials provide satisfactory thermal insulation, but allow the total thickness of the envelope components to be kept below a certain thickness. Nevertheless, in order to penetrate the building construction market, some barriers have to be overcome. One of the main issues is that testing procedures and useful data that are able to give a reliable picture of their performance when applied to real buildings have to be provided. Vacuum Insulation Panels (VIPs) are one of the most promising high performing technologies. The overall, effective, performance of a panel under actual working conditions is influenced by thermal bridging, due to the edge of the panel envelope and to the type of joint. In this paper, a study on the critical issues related to the laboratory measurement of the equivalent thermal conductivity of VIPs and their performance degradation due to vacuum loss has been carried out utilizing guarded heat flux meter apparatus. A numerical analysis has also been developed to study thermal bridging effect when VIP panels are adopted to create multilayer boards for building applications.

The Analysis of Pipeline Transportation Process for CO2 Captured From Reference Coal-Fired 900 MW Power Plant to Sequestration Region

Abstract Three commercially available intercooled compression strategies for compressing CO2 were studied. All of the compression concepts required a final delivery pressure of 153 bar at the inlet to the pipeline. Then, simulations were used to determine the maximum safe pipeline distance to subsequent booster stations as a function of inlet pressure, environmental temperature, thickness of the thermal insulation and ground level heat flux conditions. The results show that subcooled liquid transport increases energy efficiency and minimises the cost of CO2 transport over long distances under heat transfer conditions. The study also found that the thermal insulation layer should not be laid on the external surface of the pipe in atmospheric conditions in Poland. The most important problems from the environmental protection point of view are rigorous and robust hazard identification which indirectly affects CO2 transportation. This paper analyses ways of reducing transport risk by means of safety valves.

Primary energy consumption of the dwelling with solar hot water system and biomass boiler

This paper presents a new methodology, based on the energy performance of buildings Directive related European norms. It is developed to overcome ambiguities and incompleteness of these standards in determining the delivered and primary energy. The available procedures from the present “Algorithm for determining the energy demands and efficiency of technical systems in buildings”, normally used for energy performance certification of buildings, also allow detailed analyzes of the influence of particular system components on the overall system energy efficiency. The calculation example is given for a Croatian reference dwelling, equipped with a solar hot water system, backed up with a biomass boiler for space heating and domestic hot water purposes as a part of the dwelling energy performance certification. Calculations were performed for two cases corresponding to different levels of the dwelling thermal insulation with an appropriate heating system capacity, in order to investigate the influence of the building heat losses on the system design and energy consumption. The results are compared against those obtained for the conventional system with a gas boiler in terms of the primary energy consumption as well as of investment and operating costs. These results indicate great reduction in both delivered and primary energy consumption when a solar system with biomass boiler is used instead of the conventional one. Higher savings are obtained in the case of the dwelling with higher energy need for space heating. Such dwellings also have a shorter payback period than the ones with better thermal insulation.

Formal simulation model to optimize building sustainability

In this work, we present a simulation model that makes it possible to find optimal values for various building parameters and the associated impacts that reduce the energy demand or consumption of the building. In the study, we consider several situations with different levels of thermal insulation. To define and to integrate the different models, a formal language (Specification and Description Language, SDL) is used. The main reason for using this formal language is that it makes it possible to define simulation models from graphical diagrams in an unambiguous and standard way. This simplifies the multidisciplinary interaction between team members. Additionally, the fact that SDL is an ISO standard simplifies its implementation because several tools understand this language. This simplification of the model makes it possible to increase the model credibility and simplify the validation and verification processes. In the present project, the simulation tools used were SDLPS (to rule the main simulation process) and Energy+ (as a calculus engine for energy demand). The interactions between all these tools are detailed and specified in the model, allowing a deeper comprehension of the process that define the life of a building from the point of view of its sustainability.

New Construction of an Energy-surplus Day Care Center for Children to Experience Energy-efficiency

Initiated by the commitment of the mayor and public participation within the municipality Höhenkirchen-Siegertsbrunn in the South-East of Munich, the need for generating new child care facilities led to the realization of an energy-surplus day care center. This building illustrates how ecological and economic sustainability can go along with innovative techniques and architectural design, achieving high comfort and energy efficiency, simultaneously providing a child-oriented and enjoyable surrounding. This lighthouse project aims at increasing awareness and interest within the community and beyond for the issue of energy efficiency. Ensuring the successful implementation of this demanding task, a feasibility study was developed by the Fraunhofer Institute for Building Physics to define crucial key parameters for the design stage. In collaboration with the researchers a qualified team of architects and installation engineers closely worked together from the very beginning of the design process up to the end of execution, joining forces and knowledge. The project was awarded a prize by an expert committee and is supported by the Ger- man Federal Ministry of Economics and Technology within the funding program “Research for energy-optimized construction” (EnOB). This includes scientific guidance in planning, construction and start-up as well as a two-year monitoring phase.The energy concept, which is based on minimizing the energy need, includes a variety of features, partially influencing each other. Amongst others, these include a high level of thermal insulation, an optimized and demand-controlled ventilation system using preheated air and heat recovery in winter, a solar chimney for passive cooling and ventilation in summer, intelligent control systems and the use of renewable energy sources by highly efficient thermal heat pumps, solar thermal panels for hot water generation and photovoltaic panels. This solar electric system is designed to provide more electricity throughout the year than required for running the building with all its need. As electricity is the only energy carrier, both types of energy balances, primary and delivered, will result in a surplus.

Overtrawlability and Mechanical Damage of Pipe-in-Pipe

A pipeline on the seabed may be struck by moving trawl gear, and that may damage the pipeline. Trenching can be a useful but expensive way to protect the pipeline. Pipe-in-pipe and bundled pipeline systems are widely used in the offshore industry recently because of their high level of thermal insulation and because they lend themselves to rapid and economical installation. However, there is no clearly specified standard method to analyze the overtrawlability of pipe-in-pipe systems. If we apply the same method as for the single wall pipe, it is likely to result in a conservative design for the pipe-in-pipe. The objective of this paper is to investigate the overtrawlability of pipe-in-pipe, especially in the impact phase, and to fill this gap. In this study, the authors demonstrate that a quasi-static analysis can replace a dynamic analysis to some extent because the overall response does not show a big difference. The demonstration is based on both quasi-static indentation tests and impact tests for single wall pipe and pipe-in-pipe, as well as the corresponding finite element (FE) models. The FE models not only help to compare the responses but also offer a way to analyze the overtrawlability of the pipe-in-pipe. The quasi-static FE models are used for a further comparison between a pipe-in-pipe and a 406.4 mm (16 in.) single wall pipe to illustrate the overtrawlability of the pipe-in-pipe.

Green and cool roofs’ urban heat island mitigation potential in European climates for office buildings under free floating conditions

Heat island which is the most documented phenomenon of climatic change is related to the increase of urban temperatures compared to the suburban. Among the various urban heat island mitigation techniques, green and cool roofs are the most promising since they simultaneously contribute to buildings’ energy efficiency. The aim of the present paper is to study the mitigation potential of green and cool roofs by performing a comparative analysis under diverse boundary conditions defining their climatic, optical, thermal and hydrological conditions. The impact of cool roof’s thermal mass, insulation level and solar reflectance as well as the effect of green roofs’ irrigation rate and vegetation are examined. The parametric study is based on detailed simulation techniques coupled with a comparative presentation of the released integrated sensible heat for both technologies versus a conventional roof under various climatic conditions.

A 1950s CLASSIC OF THERMAL ADAPTATION TO COLD

> George Somero discusses Scholander et al.'s classic paper ‘Adaptation to cold in Arctic and tropical mammals and birds in relation to body temperature, insulation and basal metabolic rate’, published in The Biological Bulletin in 1950. It is unusual to re-visit a paper a half-century after

The Paradox of Climate Change Mitigation and Adaptation in Danish Housing

Climate change means that buildings must greatly reduce their energy consumption. It is however paradoxical that climate mitigation in Denmark has created negative energy and indoor climate problems in housing that may be made worse by climate change. A literature review has been carried out of housing schemes where climate mitigation was sought through reduced space heating demand, and it is shown that extensive problems with overheating exist. A theoretical study of regulative and design strategies for climate mitigation in new build housing has therefore been carried out, and it is shown that reducing space heating with high levels of thermal insulation and passive solar energy results in overheating and a growing demand for cooling. Climate change is expected to reduce space heating and increase cooling demand in housing. An analysis of new build housing using passive solar energy as a climate mitigation strategy has therefore been carried out in relation to future climate change scenarios. It is shown that severe indoor comfort problems can occur, questioning the relevance of passive solar energy as a climate mitigation strategy. In conclusion, a theoretical study of the interplay between climate adaptation and mitigation strategies is carried out, with a cross-disciplinary focus on users, passive design and active technologies. It is shown that the cumulative use of these strategies can create an adaptation buffer, thus eliminating problems with overheating and reducing energy consumption. New build housing should therefore be designed in relation to both current and future climate scenarios to show that the climate mitigation strategies ensure climate adaptation.

Analysis of the building energy balance to investigate the effect of thermal insulation in summer conditions

This article presents the results of a research aimed at obtaining detailed knowledge on the thermal characteristics of the building for the summer performance, particularly focusing on thermal insulation level. A new methodology for the analysis of the parameters having the most effect on space cooling energy performance of a building is presented.The proposed methodology involves analysing the different contributions to the internal air convective heat balance and their interrelations with different boundary conditions. It is applied, by means of a multi-step dynamic numerical simulation, to a parametric analysis of two case studies, a residential and an office building. The contribution of the energy transmission through the building envelope to the building energy performance for cooling is compared with the contribution of the energy not transmitted through the envelope. The influence of the single parameters related to the envelope, and in particular the effect of the thermal insulation level, are investigated through the application of a sensitivity analysis.The methodology could be used in different applications: in the energy design of new buildings or in an energy audit of existing buildings, because of its potentiality to identify critical situations and to quantify the effects of improving solutions.

A case study: the rehabilitation of residential buildings in La Mina district in Sant Adrià del Besòs (Barcelona). Functional analysis and assessment of safety conditions, habitability and maintenance

The La Mina district is a public housing development. Consisting of 2727 apartments which were built during the years 1968-74 at the height of the building sector boom, it is characterized by the mixture of building types and building methods employed and is remarkable for the use of the tunnel formwork technique. This paper presents and discusses the contents of the technical study which was prepared as a part of the Plan for Transformation and Improvement of the neighbourhood. The Plan provides for the rehabilitation of buildings and the urban reclassification and social regeneration of the neighbourhood, which is highly stigmatized as a problem area. The functional and structural safety conditions, the level of thermal and acoustic insulation, fire protection, accessibility and maintenance conditions were all analysed in detail in the technical study. In addition, several proposals were put forward for interventions aimed at reducing the most glaring deficiencies.

Optimization of energy efficiency and thermal comfort measures for residential buildings in Salamanca, Mexico

Energy use attributed to residential buildings makes up nearly 16% of the total energy consumption in Mexico, yet a larger portion of the Mexican Official Standards for Energy (NOM-ENER) are specific to the commercial building sector which only makes up 3% of the total energy consumption in Mexico. Furthermore the NOM-ENER standards related to residential buildings are developed through a component based approach where energy efficiency guidelines are outlined for individual pieces of equipment with no interactions between these components taken into consideration. In this paper, a holistic and integrative energy analysis approach is considered to improve energy efficiency in residential buildings. Specifically, the study presented in this paper investigates the interactions between various energy efficiency measures and thermal comfort measures for residential buildings in Salamanca, Guanajuato using detailed simulation and optimization procedures. The results from the optimization analysis suggest a combination of improved appliance efficiencies, increased levels of roof and wall thermal insulation and improved water heating system efficiencies is required to achieve a minimum cost solution which results in nearly 52% annual energy savings for new homes.

A method for assessing buildings’ energy efficiency by dynamic simulation and experimental activity

Buildings’ thermal-energetic assessment and the relative proposal of new technical solutions applied to both summer and winter analyses has a strategic role in increasing the year-round performance of buildings.Buildings’ dynamic analysis is by now a well-established procedure to study effective building energy performance given real climate considerations. Then in this work, a concise and effective methodology for analyzing buildings’ thermal performance in a dynamic environment is proposed and applied to different case studies, consisting of single-family residential buildings’ prototypes. This procedure is aimed to define different performance levels by proper non-dimensional indexes named thermal deviation indexes (TDI). These indexes values could express in a concise way buildings’ thermal behavior, different optimization strategies impact, sensitivity analysis results.Buildings’ prototypes representing the case studies are three free-floating houses where the architectural shape role and the sensitivity of different envelope features are analyzed, also supported by experimental results regarding envelope properties measured on existing residential buildings in Italy. The three prototypes are respectively designed to optimize summer or winter energy performance or to represent the typical Italian house before and after energy efficiency regulation is implemented. To better define the important envelope parameters necessary to calibrate the numerical models, experimental activities are conducted. In particular, thermal insulation level and roof reflectance, characterized by means of spectrophotometrical measurements, are measured both in the case of an old traditional Italian building and in the case of a modern building.The results of the dynamic analysis are expressed in terms of TDI values, to define buildings’ thermal performance with respect to the variation of all the considered architectural and envelope’s properties (i.e. architectural layout, mass and insulation, roof reflectance, Solar Heat Gain Coefficients of windows’ glasses, weather data) within a specific climatic context.For validating the proposed method, the obtained TDI results are compared with those obtained from existing procedures. In particular, the TDI values are correlated to an adaptive comfort indicator, for verifying how much the TDI could be effective for evaluating free-running buildings thermal performance during both summer and winter.

Improving thermal insulation of timber frame walls by retrofitting with vacuum insulation panels – experimental and theoretical investigations

Many of the Norwegian buildings from the 1960s–1980s with timber frame walls are ready for retrofitting. Retrofitting of these buildings with vacuum insulation panels (VIPs) may be performed without significant changes to the buildings, e.g., extension of the roof protruding and fitting of windows. Effectively, U-values low enough to fulfill passive house or zero energy requirements may be achieved; thus, contributing to a reduction of the energy use and CO2 emissions within the building sector. Retrofitting with VIPs on the exterior side is normally considered as a better solution; however, it may cause condensation in the wall. To investigate this and the interior option, four different wall fields were tested. One of them was a reference wall field built according to Norwegian building regulations from the 1970s, and three other fields represent different ways of increasing the thermal insulation level. In addition to the experiments, numerical simulations were performed where temperature, relative humidity, and surface wetness were measured. In total, the results from the experiments, simulations, and condensation controls conclude that timber frame buildings insulated with 100 mm mineral wool, might be retrofitted at the outside by adding 30 mm VIPs. However, this method for retrofitting provides limits to outdoor temperature, indoor moisture excess, and indoor temperature.

Prospects of the treatment of acoustical insulation in building codes of México.

The acoustical insulation of dwellings in order to protect them from environmental noise is an issue not yet addressed in building regulations in Mexico, but the Federal Government, through the National Housing Commission (CONAVI), has promoted the development of a Building Code for Dwellings, which in the future could include provisions about this subject. So far, authorities have focused their attention on the problems of energy efficiency and thermal insulation of public buildings. On the subject of housing, they have proposed levels of thermal insulation that could be adopted as standards and have also promoted the study of constructive solutions appropriate to those standards. The levels of acoustical and thermal insulation that are produced by various constructive solutions used by housing developers in the metropolitan area of the city of Puebla, Mexico, are analyzed in this work in order to compare their performance with international standards. A more comprehensive regulatory framework is needed in Mexico, and the results of this research will produce recommendations on acoustical insulation capacities that the National Housing Commission could include in its code. [Project supported by funds from CONACYT and CONAVI.]

A performance comparison of passive and low-energy buildings

This paper compares apartments in two residential blocks in Vienna; one passive and the other one low-energy. These blocks were constructed simultaneously in the same location and with comparable building construction features and floor plans. The main difference between the two blocks (other than the higher thermal insulation level in the passive building) lies in the ventilation system: passive buildings deploy controlled ventilation, whereas the low-energy buildings rely mostly on user-operated natural (window) ventilation. We measured indoor environmental conditions (indoor air temperature, relative humidity, and CO2 concentration) in two units of each block over a period of five months. Additionally, the buildings were compared in view of operation and embodied energy use, CO2 emissions, and construction costs.

Life-Cycle Analysis of Roofing Insulation Levels for Cold Storage Buildings

To reduce operating costs, cold storage buildings are being designed with increasing levels of thermal roof insulation. This paper examines the current state of the art in order to estimate average roof insulation requirements in modern cold storage buildings. This research includes both economic and environmental considerations. The added environmental impact of manufacturing thermal insulation is compared to the reduced environmental impact of the building’s cooling load. The cost of purchasing and installing additional roof insulation is also compared to the annual energy savings associated with the increase to establish the most economic insulating level given today’s cost of energy. This paper shows that, from an economic, as well as from an environmental performance perspective, there is a need to design more efficient, sustainable cold storage buildings now.