Building Insulation Performance Research Articles

Optimal pricing of integrated community energy system for building prosumers with P2P multi-energy trading

Buildings are typically integrated with multiple distributed energy resources (DERs), enabling them to act as building prosumers engaged in both energy production and consumption. Peer-to-peer (P2P) energy trading among building prosumers is crucial to improve their benefits. However, further exploration is required to balance the benefits between building prosumers and the system operator (e.g., the integrated community energy system (ICES) operator) since they are different entities. In this context, this paper proposes a comprehensive network charge and energy sale pricing scheme for the ICES operator on heterogeneous building prosumers with P2P multi-energy trading. The interaction between the ICES operator and building prosumers is modelled as a bi-level optimization problem that belongs to the hierarchical structure, while considering the heterogeneity of thermal insulation performance of buildings. At the upper level, the ICES operator optimizes the electricity/heat network charge prices and electricity/heat sale prices to maximize its revenue. At the lower level, building prosumers with a parallel structure optimize the schedules including P2P multi-energy trading and buildings' heating loads to minimize their costs. Furthermore, to address the bi-level optimization problem with parallel and hierarchical coupling structures, an accelerated asynchronous distributed algorithm based on alternating direction method of multipliers (ADMM) is developed, integrating a warm start strategy and a dual update accelerated iteration strategy for further improving computational efficiency. Finally, case studies demonstrate that the proposed scheme can effectively benefit both the ICES operator and building prosumers in P2P multi-energy trading at the same time. Meanwhile, the feasibility and effectiveness of the proposed algorithm are validated.

Thermal insulation performance of buildings with phase-change energy-storage wall structures

Considering that improving the energy efficiency of buildings is crucial to achieving China's carbon neutrality goal, the application of phase-change energy-storage (PCES) technology could be considered a practical and feasible approach. Currently, the heat transfer characteristics of PCES walls and their influence mechanisms on the indoor building environment are the key issues to be solved in this field. Based on gypsum-based phase-change materials (PCMs), outdoor, indoor and central PCES walls are designed in this study. Unsteady heat transfer experiments, finite element numerical simulations and energy consumption analyses were used to study the thermal behaviour of PCES walls, and the thermal insulation performance of the buildings utilizing these wall structures were assessed. The results show that the maximum temperature of inner surface of wall with PCMs applying at the interior side is reduced by 0.6 °C, and the maximum temperature lag is reduced by 0.8 h. The results also prove that buildings employing this PCES walls as envelope have a reduction of annual cooling energy consumption about 7.6%, and a reduction of annual carbon dioxide emissions by about 2%, comparing with conventional buildings. Thus, these results suggest that the use of PCES walls can effectively enhance the thermal insulation performance of buildings in summer. This research could provide an innovative idea for the design of PCES walls, which is of significance for the application of PCES walls in severe cold regions.

A Comparative Assessment of Different Aerogel-Insulated Building Walls for Enhanced Thermal Insulation Performance.

Aerogel is widely recognized as a superinsulating material with great potential for enhancing the thermal insulation performance of building walls. It can be applied in various forms such as aerogel plasters (AP), aerogel fibrous composites (AFC), and aerogel concrete (AC) in practical engineering applications. This study aims to investigate the most efficient application form for maximizing building insulation performance while minimizing the amount of aerogel used. To predict the thermal insulation performance of aerogel-insulated walls, a resistance-capacitance network model integrating the aerogels' effective thermal conductivity model was developed and was validated by comparing it with Fluent simulation software results in terms of surface temperature. Using the validated models, the thermophysical parameters, transient thermal properties, and transmission load were predicted and compared among AP, AFC, and AC walls. The results indicate that using AFC can result in approximately 50% cost savings to achieve the same thermal resistance. After adding a 20 mm thickness of aerogel to the reference wall without aerogel, the AFC wall exhibited the highest improvement in thermal insulation performance, reaching 46.0-53.5%, followed by the AP wall, and then the AC wall, aligning with considerations of microstructural perspectives, thermal resistance distributions, and thermal non-uniformity factors. Therefore, giving priority to AFC use could reduce the required amount of silica aerogel and enhance economic efficiency. These results provide valuable insights for theoretical models and the application of aerogel-insulated walls in building engineering insulation.

Potential quantification and impact factors analysis of energy flexibility in residential buildings with preheating control strategies

Demand response (DR) is an effective method for achieving energy flexibility. Preheating can store a certain amount of energy in the building while simultaneously reducing the heat load. The energy flexibility of a building during the heating season mainly depends on the types of DR events, the thermal performance of the building envelope, and weather conditions. Analyzing the impact of these factors on the preheating performance and exploring their interactions can reveal the potential for energy flexibility. This study proposes a simulation-based method to evaluate the energy flexibility of a residential building in Kitakyushu, Japan from the perspectives of energy efficiency, load and energy reduction. Rule-based control strategies are applied to heating, ventilation, and air conditioning systems. The results show that compared to preheating temperature of 24 °C, high insulation building at 25 °C achieves energy efficiency improvement of 3.5%–14.8% and load reduction increase of 1.6%–22.2%. Compared to low insulation building, preheating at 25 °C for 1 h increases energy efficiency in high insulation building by 6.2%–10.3%, with corresponding load reduction increase of 1.0%–19.1%. Extending the preheating duration improves load reduction but leads to heat loss. Preheating during heating system startup should be avoided as it produces the worst energy flexibility. Moreover, statistical analysis identifies key indicators for energy reduction: the inside surface temperature of the exterior wall (Pearson correlation coefficient = 0.820, standard regression coefficient = 0.924), followed by global horizontal radiation and building insulation performance.

The HVAC model predictive control of building thermal dynamic characteristics

As the terminal energy user of urban power grid, it is significant to model and simulate the energy consumption characteristics of buildings. First, the author proposes a thermal dynamic model to predict the energy consumption of building refrigeration/heating, it is composed of several groups of heat transient energy balance equations, which can fully consider the impact of heat convection, heat conduction and heat storage on building energy consumption during the heat transfer process of building envelope. Then, the HVAC model predictive control (MPC) method considering the thermal dynamic characteristics of the building envelope is proposed for the heating, ventilation and air conditioning, the core energy unit of the building, the change of window wall ratio in building will affect the thermal insulation performance of the building, so the window wall ratio in building design should not exceed 0.7. From the perspective of building thermal insulation performance, the author analyzes the situation that the total 48 hours operating cost of buildings under two control methods changes due to the change of building thermal insulation performance with the change of window wall ratio in different environments, the simulation results show that when using MPC control method for HVAC, the daily operating cost of buildings increases with the window wall ratio at a lower rate than the traditional control method. It can be seen that the MPC control method has a better effect of energy saving and reducing the total operating cost of buildings in response to the environment where the window wall ratio of buildings increases or the thermal insulation performance of buildings becomes worse over time. It is proved that the HVAC control method based on MPC not only helps to reduce the building energy cost, but also deals with the reduction of HVAC energy efficiency level and the deterioration of building insulation performance, it is more conducive to saving energy and improving the operating economy of buildings.

Estimation of Indoor Temperature Increments in Summers Using Heat-Flow Sensors to Assess the Impact of Roof Slab Insulation Methods

Improving the thermal insulation performance of buildings is crucial for saving energy. Currently, the insulation performance can be quantified based on the thermal resistance and thermal transmittance (U-value). However, for owners, these data are not readily available for the verification of different insulation methods. To address this, a solution could involve establishing a connection between specialized evaluation indicators and temperature, a common physical quantity. In this study, static and dynamic heat-transfer experiments were performed using an environmental simulation chamber and heat-flow sensors. Based on the tests, a simple predictive formula for the heat-flow density over time was established. After analyzing a full-scale building model, six cases of the heat-flow density versus temperature rise in indoor environments were obtained. This approach may aid owners in visually assessing the insulation performance of buildings by establishing a conversion relationship between the heat-flow density and temperature. In addition, the performance of 14 experimental specimens, including self-developed and code-documented thermal insulation materials and construction methods, was evaluated. In the simulations, after turning off indoor cooling equipment for 6 h during hot summers, the average indoor temperature increase for a roof with insulation was only 52% of that without insulation.

Experimental study on airborne sound insulation performance of lightweight double leaf panels

To create a healthy and comfortable indoor environment, higher requirements are put forward for the airborne sound insulation performance of buildings. The control of airborne noise transmission is a key measure to improve the airborne sound insulation performance of buildings. In this study, the airborne sound insulation performance of the lightweight double leaf wall was studied, and the influence of stud type, stud spacing, cavity filling (type and thickness of filling materials), panel layers (type, layer number, thickness and mass) on the airborne sound insulation performance of the lightweight wall was emphatically analyzed. The test results show that the airborne sound insulation performance of the lightweight double leaf wall can be improved by the following five measures: (1) increasing the stud spacing; (2) expanding the size of the independent panel; (3) using stone wool or glass wool as the filling materials; (4) increasing the number of panel layers or panel mass; and (5) reducing the structural connection.

Identification of control regularity of heating stations based on cross-correlation function dynamic time delay method

Efficient operation and fine control are the keys of heating stations (HSs) to reduce energy consumption and carbon emission. Identifying control regularity of HSs is significant to realize fine control. This paper firstly defines control regularity, regulation time step (RTS) and regulation time node (RTN) of HSs. Then identify HSs’ type based on insulation performance of buildings. Secondary loop supply and return temperature are chosen as characteristic parameters to determine pipe network thermal delay, while indoor temperature and the comprehensive outdoor temperature are used to determine building thermal inertia delay. Cross-correlation function dynamic time delay method is used to identify the delay time, and RTS of HS is determined. The regression model of RTS is obtained to decide daily RTNs. It is found that RTS of buildings with floor heating are larger than that with radiators, energy-saving buildings are larger than non-energy-saving buildings, and the high cold period is greater than the early and last cold period. The proposed method is applied to three HSs. Results show that average indoor temperature is maintained within the target range of 20 ± 1 °C, varies within a narrow range. Indoor temperature unevenness coefficient reduction indicates that indoor thermal comfort has been improved.

Foreword to the special issue on “New Perspectives and Attempts to Control the Sound Insulation Performance of Buildings”

Foreword to the special issue on “New Perspectives and Attempts to Control the Sound Insulation Performance of Buildings”

In-Situ Thermal Bridge Evaluation of a Building Using Bayesian Inference With Measured Infrared Thermography

Abstract Useful thermal bridge performance indicators (ITBs) of existing buildings may differ from calculated thermal bridge performance derived theoretically due to actual construction conditions, such as irregular shapes and aging. To fill this gap practically, a more realistic quantitative evaluation of thermal bridge on-site needs to be considered to identify thermal behaviors throughout exterior walls and thus improve the overall insulation performance of buildings. In this study, a case study is conducted using an infrared thermal imaging method to evaluate the thermal bridge of an existing building practically. The study's main purpose is to review the thermal bridge performance indicators measured by the steady-state model under field conditions in terms of convergence and uncertainty. Bayesian Markov Chain Monte Carlo (MCMC) is used to examine the validity of the results by deriving evaluation results in the form of distribution, including uncertainty. After the measurement was completed, an analysis of the results was conducted. As a result of measurement for 3 days, it was found that the thermal bridge part had 1.221 times more heat loss than the non-thermal bridge part, which showed a 6.7% deviation from the numerical method. However, the uncertainty was 0.225 (18.4%, CI 95%), a large figure. This is due to the influence of field conditions and shows the limitations of the steady-state measurement model. Regarding the convergence of the results, the measurement results were found to converge continuously as the measurement time increased. This suggests that valid results can be obtained in the field if the measurement is performed for a sufficient time, even with a thermal bridge measurement method assuming a steady-state.

Sound insulation performance of buildings with cross laminated timber panels

Sound insulation performance of buildings with cross laminated timber panels

Performance evaluation of air and liquid-based solar heating systems in various climates in East Asia

This study evaluates the performance of liquid and air-based solar heating systems according to climatic conditions and the thermal insulation performance of buildings. The relationship between thermal energy demand and the effects of applying solar heating systems according to building characteristics is also clarified. The effectiveness of the solar heating system depends on the characteristics of the region and the building (heating energy demand and hot water energy demand depending on the outside temperature) and the amount of solar radiation in the target area. In particular, in the case of the air-based solar heating system, separate heat exchange is required to use as a hot water supply, and due to the heat loss generated therefrom. As a result, the effect of using indoor heating is greater than the effect of using hot water. Conversely, in the case of a liquid solar heating system, hot water can be used directly for hot water supply, but when used as radiant heating, efficiency is relatively reduced due to heat loss outside the target space. We examined the annual energy demand, the annual energy-saving amount via solar heat utilization and the energy-saving rate by a simulation of representative points of 88 climates in East Asia using solar heat utilization climate classification. The liquid-type solar heat collection system is suitable for solar heat utilization in areas where the hot water supply energy demand is approximately 34% or more of the annual energy demand in low-insulation houses. On the other hand, in high-insulation houses, the air-based solar heating system is more effective when hot water energy demand is less than 73% of the annual energy demand. The results of this study can be used as a basis for determining the solar heating system suitable for the target building, and it is considered that it leads to the result of increasing the solar utilization in the houses.

Acceptable surface temperature of floor radiant heating system based on thermal comfort study in southern China

In winter, people's demand for heating is stronger and stronger in southern China, and the floor radiant heating system is more and more popular. However, there are no suitable guidelines or standards for the floor temperature of the heating system in this area. The insulation performance of buildings in southern is not as good as other area which have central heating system. So the acceptable floor temperature suitable for this area needed to be studied.12 healthy college students participated as samples in this experiment. The floor surface temperature was controlled by varying the temperature of water flowing underneath the floor. The main conclusions were as follows: 1) the floor surface temperature directly affected the skin temperature of the foot and the thermal comfort of the foot. There was a significant statistical relationship between the floor surface temperature and the overall thermal sensation. 2) The acceptable floor temperature ranged from 26.1 °C to 34.3 °C for sitting positions and 24.6 °C ~34.7 °C for standing positions. 3) Considering the head thermal comfort and the health effects of the cumulative effect of long-term heat exposure, the recommended upper limit of the floor temperature in this experiment is 31°C.

통일대비 북한 주거환경 개선 단열재 적용 시뮬레이션 연구

This study aims to improve the residential environment in North Korea. The results are summarized as follows : 1) Houses in North Korea are classified according to the class of people who are subject to move into the country. In particular, due to shortage of materials and construction equipment, the conditions of finishing materials are very poor. Also, insulation performance of buildings is very weak. 2) Out of insulation materials used in South Korea, six types(EPS, XPS, Reflective Insulation, Polyurethane Foam, Glass Wool, Polyester Board) were selected; low thermal conductivity (about 0.04W/mK) and high fire resistance, constructability and economy (about 10,000 won per unit area). Among them, polyurethane foam was found to be the best in insulating performance, and EPS had high constructability and Reflective Insulation had economical merit. 3) Heating load simulation showed that the thermal performance of poor North Korean houses such as Harmonica houses and Rural cultural houses could be improved by 40-80% depending on the application of insulation materials.

Simulation research on the dynamic thermal performance of a novel triple-glazed window filled with PCM

The window energy consumption plays an important role in the building energy consumption. Recent researches on the double-glazed window filled with PCM (DW + PCM) show that in summer, the released unwanted heat into the room in the discharge period of PCM in summer night is considerable as well as the overheating phenomenon from the completely melted PCM is non-ignorable, both of which have an adverse effect on the building insulation performance. In order to solve the problems, a configuration of triple-glazed window filled with PCM (TW + PCM) is proposed and the mathematical model is established in this paper. Through the simulation, the dynamic thermal performances of the TW + PCM are obtained. The results show that in typical sunny summer day, the temperature decrement factors are 0.75 and 0.63 respectively, and the energy consumption of TW + PCM is reduced by 21.30% and 32.80% respectively, compared with DW + PCM and triple-glazed hollow window (TW). In addition, the TW + PCM shows a good performance under the typical winter conditions. In conclusion, TW + PCM can avoid overheating phenomenon effectively and has advantageous performance on heat preservation and insulation.

Performance Improvements of the Air-Based Solar Heating System (Improvement Method of Thermal Performance)

In this study, it is proposed a heating and hot water system for a house using the air-based solar collection. The performance of existing solar heating system is analysed by annual simulation and the problems and the effect of thermal characteristics of the system are investigated due to change of heat collecting surface, heat storage method, capacity, building insulation performance and so on. Furthermore, it presents an improvement plan that maximizes the effect of the system and the performance of the system.

A Study on the Effective Adjustment of Building Insulation Performance and the Application of the Night Purge Ventilation System for Low Energy Building Design

A Study on the Effective Adjustment of Building Insulation Performance and the Application of the Night Purge Ventilation System for Low Energy Building Design

Building insulation performance and energy consumption survey on social welfare facilities in Hokkaido

Building insulation performance and energy consumption survey on social welfare facilities in Hokkaido

A city scale degree-day method to assess building space heating energy demands in Strasbourg Eurometropolis (France)

Efficient strategies are required to reduce space heating energy demands in buildings at city scale. Models taking into account the dynamic of the Urban Heat Island (UHI) phenomenon may be useful tools to help urban planners in this task. In this paper, we propose a new methodology to assess the energy demands for space heating in buildings at city scale: a degree-day method is applied, coupled with the use of a dynamic urban meteorological model that computes a building energy budget. First, it is shown that the total building space heating energy demand at city scale, as simulated by the meteorological model, is quasi- linearly dependent on the daily mean city scale air temperature. The developed city-scale degree-day method applied to assess the space heating energy demands in Strasbourg Eurometropolis (France) is shown to be consistent with the estimates issued by local official energy sources. A sensitivity analysis highlights the fact that while the heating energy demands are dependent on the building insulation performance and thermostat heating temperatures, scenarios in which building energy properties are changed do not significantly affect the UHI.

Experimental research on the dynamic thermal performance of a novel triple-pane building window filled with PCM

Phase change material (PCM) filled window shows significances in the building energy consumption. Recent researches on the double-pane window filled with PCM (DW+PCM) show that in summer, the released latent heat from PCM into the room during summer night is considerable as well as the overheating risk from the completely melted PCM is non-ignorable, both of which have adverse effects on the building insulation performance. In order to solve the problems, a configuration of triple-pane window (TW+PCM), the outer cavity of which is filled with PCM, is proposed in this paper. Experiment to investigate the thermal performance of TW+PCM is conducted in the summer days. Experimental systems of two reference windows (DW+PCM and triple-pane window (TW)) are also set up successively. The results show that compared with DW+PCM and TW, the peak temperature on the interior surface of TW+PCM reduces by 2.7°C and 5.5°C respectively, which means the overheating risk is avoided effectively, and heat entered the building through the TW+PCM reduces by 16.6% and 28% respectively in the sunny summer day. In the rainy summer day, the TW+PCM shows advantageous performance on reducing the temperature fluctuation of the interior surface and the heat entered the building.