scholarly journals Thermal Technical Analysis of Lightweight Timber-Based External Wall Structures with Ventilated Air Gap

2021 ◽  
Vol 13 (1) ◽  
pp. 378
Author(s):  
Denisa Valachova ◽  
Andrea Badurova ◽  
Iveta Skotnicova
Keyword(s):  
Thermal Analysis ◽  
Theoretical Data ◽  
Energy Performance ◽  
Heat Emission ◽  
Air Gap ◽  
Cold Night ◽  
External Wall ◽  
Roof Structure ◽  
Wall Structures ◽  
Ventilated Facade

Lightweight timber-based structures are an increasingly common part of envelopes of new buildings due to increasing requirements for their energy performance. In addition, due to the fact that wood is a sustainable material, it can be assumed that the share of these structures in civil engineering will continue to increase. The subject of this article is the thermal analysis of timber-based lightweight structures under winter conditions to expand information about thermal processes in these structures. This article deals with the lightweight timber-based external wall structures with a ventilated facade and a double-skin roof structure. Experimental temperature measurements inside the structures and ventilated air gaps are used to perform the thermal analysis. By comparing experimental and theoretical data obtained by performing numerical simulation, it was shown that for achieving an ideal match of numerical simulations and measured physical properties it is necessary to take into account not only external temperatures affecting these structures, but also other factors such as solar radiation and heat emission into the cold night sky. In the case of the external walls with ventilated facade, the benefit of a ventilated air gap has been demonstrated in relation to smaller temperature fluctuations that affect the structures.

scholarly journals Impact of Insulation Type and Thickness on the Dynamic Thermal Characteristics of an External Wall Structure

2018 ◽  
Vol 10 (8) ◽  
pp. 2835 ◽  
Author(s):  
Jihui Yuan
Keyword(s):  
Time Lag ◽  
Thermal Characteristics ◽  
Thermal Capacity ◽  
Wall Structure ◽  
External Wall ◽  
Thermal Transmittance ◽  
Wall Structures ◽  
The Impact ◽  
Time Lead ◽  
Surface Factor

The dynamic thermal characteristics of external wall structures are directly related to indoor thermal comfort and energy savings in buildings; they are also complicated and worth investigating. Thermal insulation in external wall structures has become a popular topic of investigation in the domain of building energy efficiency. This study aims to find the impact of insulation type and thickness on the dynamic thermal characteristics of external wall structures using a homogeneous multi-layer building external wall structure and three types of insulation materials that are widely used in Japan. The impact of insulation type and thickness on seven thermal characteristics of external walls, including thermal transmittance, decrement factor or amplitude attenuation, time lag, thermal admittance, time lead for thermal admittance, surface factor, and thermal capacity, was evaluated by numerical methods in this study. It was shown that insulation type and thickness would have a significant effect on thermal transmittance, decrement factor and time lag, but yield no significant change in thermal admittance, time lead for thermal admittance, surface factor, and the thermal capacity of external wall structures.

scholarly journals Annual performance analysis of heat emission in radiator and underfloor heating systems in the European reference room.

2019 ◽  
Vol 111 ◽  
pp. 04009
Author(s):  
Karl-Villem Võsa ◽  
Andrea Ferrantelli ◽  
Jarek Kurnitski
Keyword(s):  
Performance Indicator ◽  
Energy Performance ◽  
Heat Emission ◽  
Test Facility ◽  
Climate Data ◽  
Energy Usage ◽  
Operative Temperature ◽  
Heating Systems ◽  
Emission Efficiency ◽  
University Of Technology

In this paper, we investigate the energy usage and emission efficiency of radiator and underfloor heating systems coupled with ON/OFF and PI controls, by performing annual simulations with the IDA ICE software package. Results from measurements carried out in early 2018 at the nZEB test facility near the Tallinn University of Technology are used to calibrate validated emitter and controller models. The calibrated models are then used to assess the energy performance of the systems in a simulation spanning the whole year, using climate data for Strasbourg in the European reference room. The annual simulation is conducted in a specific room with fixed geometry and boundary conditions. As a novelty value of the present study, we impose a non-standard control strategy based on maintaining a specified operative temperature within the room. A single-valued performance indicator, in the form of an increased air temperature set-point, is accordingly obtained for each emitter configuration to be used in further calculations of hourly, monthly or annual heating energy usage. Such a temperature increment accounts for imperfect control, air stratification within the room and the additional temperature increase that is required for achieving a desired operative temperature.

scholarly journals A MULTIPLE CRITERIA DECISION SUPPORT SYSTEM FOR ANALYZING THE CORRELATION BETWEEN THE THICKNESS OF A THERMO-INSULATION LAYER AND ITS PAYBACK PERIOD OF THE EXTERNAL WALL

2015 ◽  
Vol 21 (6) ◽  
pp. 827-835 ◽  
Author(s):  
Donatas Aviža ◽  
Zenonas Turskis ◽  
Artūras Kaklauskas
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Management System ◽  
Energy Performance ◽  
Payback Period ◽  
Multiple Criteria ◽  
Insulation Layer ◽  
Model Base ◽  
External Wall

A case study provides the correlation analysis of the thickness of the thermo-insulation layer (expanded polystyrene – EPS70) of the typical details of the external wall and energy performance class in a modern newly constructed residential low-energy building (one and two-room apartment). The conducted analysis focused on what impact different geographical areas of building construction and different energy performance classes of the building may had on the thickness of the thermo-insulation layer. Lithuania was chosen as the object of this study. Calculations were carried out in seven towns, including Vilnius, Klaipeda, Kaunas, Siauliai, Panevezys, Utena and Dukstas. According to requirements for legal acts passed in the Republic of Lithuania and to Directive 2010/31/EU (2010), as a result, the necessary thickness of thermo-insulation layers (EPS70) and a payback period were calculated. A multiple criteria decision support system for analyzing the correlation between the thickness of the thermo-insulation layer and its payback period of the external wall (DSS-ACTILPW) consisting of a database, a database management system, a model-base, a model-base management system and a user interface was developed. Information on the performed analysis is important to building designers, energy consumption auditors and investment experts who make the final decisions on energy efficiency of buildings in the residential building sector.

scholarly journals A Novel Method for Calculating the Product Category Specific Setpoint Variations for Heat Emitters in EN15316-2

2019 ◽  
Author(s):  
Karl-Villem Võsa ◽  
Andrea Ferrantelli ◽  
Jarek Kurnitski
Keyword(s):  
Product Category ◽  
Heating System ◽  
Energy Performance ◽  
Heat Emission ◽  
International Standards ◽  
Vertical Stratification ◽  
Variation Method ◽  
Cross Correlations ◽  
System Configurations ◽  
And Control

Estimating heat emission losses of heating systems is an important task of energy efficiency assessments in buildings. To this aim, the present international standards contain tabulated values for different emitter and control system configurations, without however explaining how to compute the effect of increased setpoint temperatures on the system losses. Moreover, the effects of each component are treated as independent, while e.g. vertical stratification and temperature control of the system are cross-related. In this paper we attempt to fill this gap by proposing a calculation method to calculate the product category specific setpoint variations for space heating emitters, accounting for the overall heat balance in the enclosure and including the cross-correlations of each component as well. The emission losses of a heating system are computed using a temperature setpoint variation method that is imposed on annual energy calculations. This complements the procedure presented in the Standard EN15316-2, also providing the possibility to use product-specific values of setpoint variations instead of tabulated values. As the main finding of the study, the calculation process is defined for a European Reference Room, namely for a specific enclosure that allows an accurate and transparent evaluation of the total setpoint variation. The product-specific values of setpoint variations are calculated from measured vertical stratification and control parameters with an annual simulation model of the European Reference Room. The total setpoint variations were simulated for a set of heat emitters and controllers in order to quantify and compare the energy performance of a new and an old type building located in Strasbourg. We find that the total setpoint variation required to overcome emission losses is up to 2.00 °C in the old building and 1.20 °C in the new building, corresponding respectively to an increase in total heating energy usage of up to 22% and 20%.

scholarly journals External Wall Technological Solutions for Carbon Zero Schools in Italy

Proceedings ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 13
Author(s):  
Cecilia Ciacci ◽  
Frida Bazzocchi ◽  
Vincenzo Di Naso
Keyword(s):  
Environmental Impact ◽  
Design Process ◽  
Energy Performance ◽  
School Building ◽  
Technological Solution ◽  
Insulation Layer ◽  
External Wall ◽  
Early Stages

For the construction of a carbon zero school building, it is necessary to choose a proper technological solution for the external wall in the early stages of the design process. At the same time, the material to be used for the insulation layer must be defined. The main aim of the presented study is to analyze five different technological solutions for the external wall combined with four different materials for the insulation layer. The solutions will be used in a new typological model for kindergarten and analyzed and compared with respect to both environmental impact and energy performance.

Sign in / Sign up

Export Citation Format

Share Document