Carl-Eric Hagentoft

Carl-Eric Hagentoft
Chalmers University of Technology · Architecture and Civil Engineering, Chalmers University of Technology

Professor

About

93
Publications
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Introduction
Skills and Expertise

Publications

Publications (93)
Article
Full-text available
Some Swedish school buildings built in the 1960s and 1970s experience indoor air quality problems, where the contaminants are suspected to come from the crawl space underneath the building. The poor indoor air quality causes discomfort among pupils and teachers. Installing an exhaust fan to maintain a negative pressure difference in the crawl space...
Article
Full-text available
Buried and operating district heating (DH) pipes are exposed to thermal degradation of their polyurethane (PUR) insulation over time, and their status is hard to assess without excavation. By using DH pipe valves in manholes as measurement points during a shutdown with an ensuing cooling period, non-destructive assessments can be performed. This st...
Article
Full-text available
This study evaluates temperatures measured at district heating (DH) valves in manholes and their usability for non-destructively assessing the thermal performance of buried DH pipes. The study was conducted as a field test in which part of a DH network was shut down and the temperature decline in the valves was analysed in terms of absolute tempera...
Article
Lately, a new technical solution, pre-compressed joint sealing tapes in precast concrete sandwich panel facades, has been introduced in Sweden. Although the consequences of performance failure can go far beyond the component, affecting the building, the introduction has gained little attention in terms of risk assessment in the literature and in in...
Article
Full-text available
Design-build contractors are challenged with the task of minimizing failure risks when introducing new technical solutions or adapting technical solutions to new conditions, e.g., climate change. They seem to have a disproportional trust in suppliers and their reference cases and might not have adequate resources or methodologies for sufficient eva...
Article
Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less dev...
Chapter
Air movement in and through the building envelope often plays a leading role in the transport of moisture and heat into the building. It is caused by pressure and temperature variations around the building envelope. Pressure changes are caused not only by the weather conditions, but also by the ventilation system, the distribution of air leakages,...
Article
Full-text available
The paper presents a simplified conceptual model for energy demand calculations based on building envelope characteristics, thermal mass and local climate. It is based on a network model and lumped analysis of the dynamic process. Characteristic parameters for the buildings are suggested; Driving temperature (DT), Driving temperature difference, (D...
Article
Full-text available
Serial failures have occurred when introducing new technical solutions in the Swedish construction industry. In an earlier interview study exploring introduction of new technical solutions, documentation and reference cases provided by the supplier are given as the main sources for evaluation. This paper aims at addressing the questions: 1. What ki...
Article
Full-text available
Several school buildings in Sweden have indoor air quality problems. The contaminant source is often assumed to come from within the construction, for example from the crawl space or attic space. Contaminants, in these cases, are transported by air leaking between compartments in the building. Here, the driving force for the air leakage is differen...
Article
Full-text available
The water vapor transfer between the indoor air and hygroscopic finishing materials is of importance for the moisture balance of the room. Most protocols for determining the effect are based on isothermal conditions and cycling relative humidity in the form of square wave or sinusoidal functions. A new analytical solution for a material exposed to...
Conference Paper
New types of energy smart window curtains, with the aim to reduce the heat losses through windows have been studied. By covering windows with these curtains, for instance when buildings are not occupied, the energy performance can be improved and becomes more economical and sustainable. The paper aims to evaluate the energy performance of the curta...
Article
For many industrial applications, heat flow through composites relates directly to energy usage and thus is of highest interest. For multilayer composites, the heat flow is a result of multiple variables, such as the temperature gradient over the surface boundaries and each material's thermal conductivity, specific heat, and thickness. In addition,...
Conference Paper
An environmental friendly method to mitigate the slippery condition on road surfaces is to use a Hydronic Heating Pavement (HHP). The performance of the HHP system strongly depends on its design parameters. The aim of this study is to investigate the effects of different design parameters of the HHP system on the anti-icing operation of the road su...
Article
The traditional method for anti-icing roads is distributing salt and sand. However, the method causes environmental pollution and damages to road infrastructures. A renewable alternative method for winter maintenance of roads is to use Hydronic Heating Pavement (HHP), coupled to a Ground Heat Exchanger (GHE). The aim of this paper is to examine the...
Article
A simplified wall assembly consisting of four material elements is considered. Optional vapor retarder and thermal resistances are located between the elements. A simplified numerical model is presented to perform probability-based risk analysis using the Monte Carlo method. The risk assessment of the wall assembly considers the interior and exteri...
Article
Full-text available
The water vapour transfer between the indoor air and material surfaces is of importance for the moisture balance of the room. It can also be important for the moisture content and durability of the material surface layer such as artefacts in churches and historical buildings. For most building materials the penetration depth due to short time fluct...
Article
Full-text available
Hydronic Heating Pavement (HHP) is an environmentally friendly method for anti-icing the roads. The HHP system harvests solar energy during summer, stores it in a Seasonal Thermal Energy Storage (STES) and releases the stored energy for anti-icing the road surface during winter. The aims of this study are to investigate: (i) the feasibility of HHP...
Article
Full-text available
Climate change is a growing threat to cultural heritage buildings and objects. Objects housed in historic buildings are at risk because the indoor environments in these buildings are difficult to control and often influenced by the outdoor climate. Hygroscopic materials, such as wood, will gain and release moisture during changes in relative humidi...
Conference Paper
Full-text available
Many schools in Sweden, have problems with the indoor air, affecting the well-being and health of both pupil and teachers. Contaminants in the air, such as mold spores, radon, odors, and VOC, cause problems and it can be difficult to find the contaminant source, in particular if it is within the building construction. The aim of this project is to...
Conference Paper
Full-text available
There is a need of more knowledge about the mechanisms of water leakage through façades exposed to driving rain to make reliable risk analyses. Therefore, we have studied it in more detail and the outcome include inter alia a new algorithm. The algorithm is developed for calculation of water leakages through rain screen deficiencies. The algorithm...
Article
The aim of this study is to determine the optimal required energy for anti-icing the road surface using a Hydronic Heating Pavement (HHP). A hybrid 3D numerical model is used to simulate the transient anti-icing operation of the HHP system. Moreover, a superposition principle is used to separate the numerical simulation model into two fundamental s...
Conference Paper
Mold growth in cold attic constructions has become an increasing problem in Sweden and other countries with cold climates due to the demands on energy efficient building envelopes. Highly insulated building envelopes with cold ventilated attics lead to colder climates in the attic space, which increases the risk for mold growth. In this paper, the...
Conference Paper
As the design of the building envelope has changed, the parameters that govern thermal insulation, air tightness and the complex heat transfer processes are often neglected. This aim of this research work is to numerically investigate the influence of natural convection in attics with joists and insulation. With the help of Computational Fluid Dyna...
Conference Paper
Full-text available
A renewable method to mitigate the slippery condition on road surfaces is to use Hydronic Heating Pavement (HHP) system. The HHP system starts heating the road when the surface temperature is below both of the dew-point and the water freezing temperatures. Furthermore, in order to improve the anti-icing performance of the HHP system, it is necessar...
Article
A traditional method to mitigate slippery conditions on a road surface is to spread out sand and salt. This method results in corrosion of the road infrastructures and damage to surrounding vegetation. A renewable alternative method for anti-icing the road surface is to use a Hydronic Heating Pavement (HHP). The HHP consists of embedded pipes in th...
Conference Paper
There is a need of upgrading the old building stock with respect to the thermal insulation of the building envelope and specifically the façades. There are a number of systems on the market and some are quite new and innovative. In order to bring down the cost some of the systems many are based on prefabricated moisture tight insulated units. This...
Article
The scope of the annex has been to develop and provide decision support data and tools for energy retrofitting measures. A suggested risk management process is presented. Requirements on general guidelines, which can speed up the decision process and at the same time raise awareness for the associated risks, are suggested. A guideline for the retro...
Article
Full-text available
Problems with high humidity levels and mold growth in cold attics have been increasing over the last few years. The high humidity levels are to a large extent a consequence of the increasing demand on energy efficiency. Houses are frequently retrofitted with additional attic insulation, which leads to a colder attic space and hence a higher humidit...
Article
Full-text available
Power demands for heating of buildings vary a lot over the day and between seasons. These variations cause uneven supply of heat in district heating networks, which is both inefficient and costly. The buildings that are connected to the district heating system can be potentially utilized as auxiliary thermal storages to smooth out the variations in...
Article
Full-text available
The paper analyses the impact of air flow between an existing construction and an attached thermal insulation module. The paper presents general and handy formulas which can be used to determine the degradation of the U-value due to forced and natural induced air flows. The presented formulas accounts for varying insulation degree of the existing w...
Article
In Swedish district heating networks, around 10% of the supplied thermal energy is lost in the distribution system. One solution to decrease the losses is to use hybrid insulation district heating pipes, a concept where the innermost part of the thermal insulation consists of vacuum insulation panels, held in place by polyurethane foam. One problem...
Conference Paper
Full-text available
In Sweden, around 10% of the energy supplied to the district heating networks are lost through heat losses from the distribution pipes. In cylindrical geometries it is preferable to improve the insulation as close to the center as possible. This has resulted in a hybrid insulation district heating pipe concept with a combination of vacuum insulatio...
Conference Paper
Full-text available
A variable U-value would be beneficial for a buildings thermal performance. One way to switch the U-value of a wall, insulated with nano-porous material, is to change the internal pressure of the insulation This paper present thermal conductivity measurements showing a possible variation around of 3 times for a fumed silica and less than 2 times fo...
Technical Report
Full-text available
Tidigare forskning vid Byggnadsfysik, Chalmers har teoretiskt visat på hur golvvärmesystem kan göras enklare, robustare och billigare. Ett självreglerande golvvärmesystem behöver färre komponenter än konventionella återkopplande system. De simuleringar och analyser som denna experimentella studie baseras på visar på hur man kan dra nytta av internv...
Article
Old listed buildings need to be retrofitted to reduce the energy use for heating. The possible thickness of the insulation layer is limited by the existing construction. Vacuum insulation panels (VIPs) require less thickness than conventional insulation materials to reach the same thermal resistance. Therefore, it could be more appropriate to use V...
Article
Many old listed buildings have an unsatisfactory thermal performance compared to the standards of today. The listing often limits the position and necessary thickness of an added insulation layer in the building envelope. Vacuum insulation panels (VIP) present unprecedented possibilities to reduce the required thickness of the insulation layer. The...
Article
Full-text available
A standard TPS measurement gives the thermal conductivity and thermal diffusivity of an isotropic material which in turn gives the heat capacity. The thermal properties of an anisotropic material can be measured if the heat capacity is known. A method for heat capacity measurement exists, where the TPS sensor is attached to a sample container which...
Conference Paper
This study evaluates the heat and moisture performance of wooden stud walls with aerogel blankets as the main insulation. There is always a risk that a newmaterial will create problems if it is applied in the same way as conventional materials.To predict and prevent such problems, it is of essential interest to analyze aerogel applications from a h...
Chapter
Field surveys and experiences of cold attics show that these are risk constructions. Both old and new constructions are facing problems. For old constructions there is a clear correlation with improved attic floor insulations. In this chapter the hygrothermal condition of the attic is simulated both using simplified as well as more advanced models....
Article
Full-text available
The energy use in buildings has to be decreased to reach the targets and regulations in the European Union. One way of reducing the energy demand is to use vacuum insulation panels (VIP) in the building envelope. To make sure the declared thermal properties of the VIP are valid for the mounted panels, in situ measurements are needed. The transient...
Article
A model based predictive control method is applied in order to determine the optimal supply fluid temperature in the case of concrete embedded water-based floor heating in low energy residential buildings. The aim of the control is to keep the indoor temperature within a defined comfort interval. The forthcoming supply fluid temperature is obtained...
Conference Paper
Full-text available
At the construction site only visual, physical and dimension controlling of Vacuum Insulation Panels (VIP) are possible. However, there is a need of fast and accurate determination of the thermal properties of the product. The properties can be measured using a direct measurement method such as the Transient Plane Source (TPS) method. To investigat...
Conference Paper
The indoor moisture production is of great interest when simulating the indoor air humidity. Surface materials in an apartment will buffer some of the moisture produced depending on the features of the materials. Monte Carlo simulation of stochastically chosen moisture production rates in dwellings coupled to the moisture buffering capacity of surf...
Article
Advanced numerical simulations have shown that the risk for mold growth in cold attics can be substantially reduced, and even eliminated, if the cold attic is sealed and fitted with adaptive ventilation. A basic system would be comprised of mechanical fans and dampers controlled by attic and outdoor climate sensors installed in a sealed attic witho...
Article
The idea of reliability analysis in building physics design is presented. Reliability of building performance is described in terms of the probability of exceeding the critical values by the physical measures as a result of the changes of physical state of a building due to variations of climatic, structural or serviceability parameters.Demand–capa...
Article
The probabilistic model (PROMO) applied to the problem of air infiltration in low-rise buildings is presented. The model allows estimation of the effect of variations of climatic conditions on air exchange in a building. Probabilistic output in the form of probability density function of air change rate forms a ground for reliability analysis of ad...
Article
The International Building Physics Toolbox (IBPT) is a software library developed originally for heat, air and moisture system analysis in building physics. The toolbox is constructed as a modular structure of standard building elements, using the graphical programming language Simulink. To enable development of the toolbox, a common modelling plat...
Article
This paper presents analytical formulae and numerical results for the influence of water percolation on the ground temperature and the heat loss in the case of basement foundation. The influence of flowing ground water is presented as a function depending on non-dimensional parameters, accounting for flow rate, height and thermal insulation of the...
Conference Paper
Full-text available
: Today, radiant floor heating is the most frequently used heating supply system in newly built Swedish single-family houses. Most simulation tools for heat transfer calculations in whole buildings are simplified regarding the distribution of long-wave radiation (LWR) dominating the total heat transfer from a radiant floor heating system. In this p...
Conference Paper
Full-text available
Presence of volatile organic compounds in indoor air affects human health. Throat and eye irritation together with headache and weakness are symptoms related to volatile organic compounds. Hundreds of these compounds are normally present in indoor air. This paper presents a numerical simulation tool which is developed with the purpose to assess the...
Article
Presence of volatile organic compounds in indoor air affects human health. Throat and eye irritation together with headache and weakness are symptoms related to volatile organic compounds. Hundreds of these compounds are normally present in indoor air. This paper presents a numerical simulation tool which is developed with the purpose to assess the...
Conference Paper
Probabilistic model of thermal transmittance (U-value) for a building with light-weight construction is presented. Steady-state conditions of airflow and heat flow through the structure are assumed. Three cases, dependent on the direction of the airflow through the envelope, are considered: tight envelope, infiltration and exfiltration. Thermal tra...
Conference Paper
A new approach to address the memory effects of the building component is demonstrated in the paper. As an output of the analysis the probability distribution for the surface temperature and relative humidity is given, which is interesting for the determination of both thermal comfort and the risk of mould formation. Three different wall constructi...
Article
Application of limit state approach for the reliability analysis of building performance in the context of building physics characteristics is presented. Analysis of the probability of surface condensation on windows carried out on the basis of statistical description of the climatic parameters and the moisture production is shown as an example of...
Article
Implications of moisture in building and construction are of interest to the international community because of their huge economical consequences, including effects on health, maintenance and repair, retrofitting and conservation, as well as on common welfare. The present day knowledge offers a potential to tackle such problems, both in the design...
Article
Full-text available
The standardised Glaser method for calculation, prediction and evaluation of moisture performance is considered as rarely applicable. The present state of knowledge, analytical as well as experimental, concerning heat, air and moisture demands updating of standards. This paper presents five numerical benchmark cases for the quality assessment of si...
Article
Full-text available
The international building physics toolbox (IBPT) is a software library specially constructed for HAM system analysis in building physics. The toolbox is constructed as a modular structure of the standard building elements using the graphical programming language Simulink. Two research groups have participated in this project. In order to enable th...
Article
Analytical solutions for the steady-state ground heat loss for buildings with only perimeter insulations are derived. Interior and exterior edge insulations are treated in detail. A number of asymptotic solutions are presented. The two-dimensional case considered, accounts for adiabatic edge insulations with varying tilting angle and width. As a sp...
Article
This paper presents an analytical method of determining the periodic heat loss for an uninsulated slab on the ground. General integral equations are derived for the mixed boundary value problem of a half-plane, with prescribed periodic temperature on both sides of a totally insulated segment.
Article
This paper deals with numerical computations carried out to predict the effect of natural convection on the thermal performance of porous material. The effect of natural convection in a horizontal porous layer on heat transfer will be discussed. The study of this configuration is essential to understanding the performance of insulation of the type...
Article
Thick layers of highly permeable loose-fill insulation are used to thermally insulate attics in modern building technology. Since the use of highly permeable insulation leads to an increase in air movement not only in the porous layer (insulation) but also in the fluid layer (attics), it is therefore of paramount interest to determine the influence...
Article
This paper proposes an algorithm to accelerate simulations of si multaneous heat and gas transfer in gas-filled insulating foams, based on an analy sis of the different transfer processes. This algorithm combines explicit finite dif ference and over-relaxation schemes: the time step of a simulation is determined by diffusion of gases, which is calc...
Article
A simplified model for the aging of gas-filled thermal insulating foams is developed. This model is used to predict gas composition, gas partial pressures, and thermal performance of foams. The coupling between heat and gas transfer is one ofthe characteristic features ofthe model. The temperature dependency of gas perme ability, which has been fou...
Article
: A numerical and experimental study is performed to analyze the influence of natural convection on heat transfer in a composite system comprising a porous material heated from below and an air space situated above this. The numerical model is verified by conducting a number of experiments, on a model material consisting of polystyrene pellets of c...
Article
Analytical formulae are presented for the temperature and the heat loss for the case of a finite ground water flow rate. Both uninsulated and insulated ground slabs are studied. The formulae account for different thermal conductivities above and below the ground water table.