Simulation Of Thermal Performance Research Articles

Research on thermal insulation performance and application simulation of high-temperature vacuum insulation panel

Research on thermal insulation performance and application simulation of high-temperature vacuum insulation panel

Thermal Performance and Building Energy Simulation of Precast Insulation Walls in Two Climate Zones

Traditional concrete buildings exhibit low energy consumption and high heat loss, which results in a larger environmental problem. Precast insulation walls are proposed for strengthening thermal insulation efficiency and mitigating heat loss. Numerous studies have investigated the thermal performance of insulation walls over the past decades. However, gaps remain in practical engineering applications. This study aims to bridge these gaps by providing practical design recommendations based on experimental research. Nine different types of precast insulation walls were tested to examine the thermal performance, and the parameters of the insulation material, insulation form, insulation layer thickness, and concrete rib width were investigated. Then, numerical models of these walls were developed for simulating the thermal performance of the tested specimens. Finally, a six-story student apartment model using designed walls was developed to assess energy consumption in two distinct climate zones: the hot summer and cold winter zone of Changsha City, and the cold zone of Harbin City. The results indicate that the precast insulation wall with external insulation form shows better thermal performance than the sandwich insulation form. It is recommended to use precast insulation walls with 50 mm extruded polystyrene (XPS) external thermal insulation form in Changsha City and 80 mm XPS external thermal insulation form in Harbin City. Furthermore, buildings using precast insulation walls can significantly reduce energy consumption by 49.25% in Changsha and 49.38% in Harbin compared to traditional concrete wall buildings. Based on these findings, suitable design suggestions for this precast concrete wall panel building composed of insulation walls are given.

Integration of Photovoltaic Cells in Building Shading Devices:

This study focuses on the thermal performance simulation of the CSERS administrative building. It proposed the integration of shading elements on the south façade of the building to enhance thermal comfort for office occupants. These shading elements incorporate photovoltaic cells, displaying the potential of utilizing photovoltaic in external shading devices. The main objective of this approach is effectively address issues related to high internal temperatures and excessive solar radiation exposure. Furthermore, it ensures the preservation of key functions of the building envelope, such as thermal insulation, provision of natural lighting, and prevention of internal thermal glare. Comparative analysis is conducted between the building equipped with shading devices and the one without, with a focus on measuring the total electrical energy generated by the photovoltaic panels. Simulation programs such as SketchUp and EnergyPlus are utilized for this purpose. The results of the simulations reveal that strategically designed shading on south-facing windows leads to 17.15% reduction in annual heat gains transmitted to the building. In addition, the integration of photovoltaic shading devices demonstrates outstanding performance characteristics, contributing a productive capacity of around 5916.388 MW/h to the building. This integration effectively harnesses solar energy to improve the indoor environment of the building.

Numerical simulation of thermal performance of heat sink augmented with phase change material PCM integrated with solid and aluminum metal foam fins

AbstractThis study introduced a novel numerical modeling for the evaluation of a hybrid heat sink design by replacing the solid fins with aluminum foam fins (AFF) for the same thickness of 2 mm within a phase change material (PCM). This innovation is designed to enhance thermal performance in electronic cooling applications. Heat fluxes of 2, 3, and 4 kW/m2 were applied to the base. The performance has been verified at set point temperatures (SPT) of 60°C, 70°C, and 80°C, encompassing a range relevant to various applications. Different AFF thicknesses (4 and 6 mm) and foam porosities (0.85, 0.90, and 0.95) were investigated. The study demonstrated that AFFs improve heat transfer by increasing fin surface area and by effectively raising the thermal conductivity of the PCM. Compared to the SF heat sink, the results show that the AFF design extended the operational time by 5%–8% for the range of heat fluxes. Notably, AFFs with a thickness of 6 mm achieved a significant 41% improvement in the operation time at a lower SPT (60°C). The metal foam porosity of ε = 0.85 exhibited superior thermal performance within the investigated temperature range. This research paves the way for optimizing hybrid heat sink designs using metal foam for efficient thermal management and reduction of weight.

Thermal performance simulation and numerical analysis of a fuel cell waste heat utilization system for automotive application

To recover the waste heat generated by proton exchange membrane fuel cells, an onboard fuel cell waste heat utilization system used for cockpit heating was constructed in this study. The heat transfer numerical model of the system was established, and experimental data validated the feasibility of the model. Additionally, the thermal performance of the onboard fuel cell waste heat utilization system was analyzed under various operational conditions. The results indicate that the air temperature and heat transfer coefficient of the heat exchanger are positively correlated with the thermal performance of the cockpit heating, while the radiator inlet air velocity and pump speed show a negative correlation with the system’s performance. Under other steady conditions, the stabilized temperature of the cockpit is increased by 150 % when the air temperature increases from 0 °C to 40 °C, and the cockpit temperature is reduced by 20 % when the water pump speed accelerates from 100 to 300 r/min. Furthermore, under 20 °C ambient temperatures and with an inlet air velocity of 3 m/s, water pump speed of 500 r/min, and a heat exchange coefficient of 5,000 W·m−2·K−1, the fuel cell waste heat utilization system achieves an optimal waste heat utilization efficiency of 50.8 % underrated working conditions. In summary, this study offers theoretical guidance for designing and numerically evaluating a vehicular waste heat utilization system using fuel cells.

Comparison of experimental results with numerical simulation of thermal performance in car radiator using MWCNT/EG/water nanofluid

Comparison of experimental results with numerical simulation of thermal performance in car radiator using MWCNT/EG/water nanofluid

Defining the calibration process for building thermal performance simulation during the warm season: a case study of a single-family log house

ABSTRACT The study aimed to develop a holistic, evidence-based calibration strategy and define a hybrid step-by-step methodology for building thermal simulations during the warm season. The methodology was demonstrated using the thermal performance of a naturally ventilated single-family log house in a temperate climate. The calibration process was supported by on-site measurements of indoor thermal conditions and occupant behavioural reports between April and July. Hybrid calibration methodology combines statistical indicators, such as NMBE, CV(RMSE), and R 2, and a graphical evaluation of the deviation between the simulated and measured values. After 28 proposed calibration steps, a final calibrated model predicted the actual thermal response of the log house with an accuracy of ±1°C at 71.6% or ±2°C at 98.4% of the considered time. The results showed that occupant-related information, material properties and infiltration rates are crucial to improving the reliability of building thermal models. Moreover, in the calibration process of log houses, appropriate determination of building envelope materials’ thermal conductivity, wood's solar absorptivity, and airtightness showed high importance. The study highlights the importance of calibration for reliable building thermal models, specifically in overheating prevention simulations.

Thermal performance simulation of parabolic trough collector with ternary nanofluid flows and half-star-shaped fins inserts in different receivers

Thermal performance simulation of parabolic trough collector with ternary nanofluid flows and half-star-shaped fins inserts in different receivers

Fast assessment method of annual energy consumption for DSF and SSFs

Double skin façade (DSF) is widely used to improve energy efficiency in buildings. Many studies have analyzed the thermal performance of DSF and single skin façade (SSF) on just standard days or typical moments. However, in order to more accurately analyze its energy-saving effect, its annual thermal performance should be evaluated. For achieving this, a large number of simulations are needed and it is extremely time consuming and complicated. This study provides a new fast calculation method for annual thermal performance and energy consumption of DSF and SSFs. Firstly, based on CFD technique, a simulation method for obtaining indoor temperature of DSF during whole year was established, and the results were verified through experiments. Then, a new simulation calculation method for heating and cooling periods was established, thereby completing annual thermal performance simulation of different facades. Finally, based on total heat gain/loss of each facade, the energy consumption of mentioned facades was calculated, and facades’ various performance can be seen for entire year. As an overall result for Beijing located in cold region, by considering whole year energy consumption, DSF plays as the best one with 18 % energy saving in the whole year compared to the second one which is 3 glazing exterior shading SSF; however, this SSF can save 37 % building area compared to DSF. The result of this study can be useable for other cities with same climate as the Beijing. The analyze method proposed in this study is useable for optimizing building facades in different climates.

Numerical simulation of thermal performance of H2O-EGS and CO2-EGS based on thermal-hydraulic-mechanical coupling method

The use of hydrothermal geothermal methods in Enhanced Geothermal Systems (EGS) presents challenges like reduced thermal storage life and high external energy consumption. Due to its stable heat production time and lower external energy demand, CO2 has the potential to be substituted for H2O. The research zone for this study was chosen to be located in the HDR reservoir in the Gonghe Basin of Qinghai. A three-dimensional discrete fracture model based on a thermal-hydraulic-mechanical coupling method is established, where numerical simulations are conducted using COMSOL software. The discussion focuses on the comparison of heat production effects between H2O-EGS and CO2-EGS in different injection and extraction scenarios are discussed. The results indicate that by lowering the injection temperature and increasing the injection rate, the EGS net heat production rate can be increased, but it also accelerates the heat breakthrough time and shortens the reservoir life. Although CO2-EGS has a lower heat extraction rate in the early stage of thermal recovery than H2O-EGS, it has a longer stable heat production time and a more energy-efficient heat production process. Therefore, compared to H2O-EGS, CO2-EGS has more economic and social benefits.

Numerical simulation of thermal performance based on cogeneration low carbon heating unit manufacturing

The renewable energy complementary cogeneration system has broad application prospects in the field of regional comprehensive energy utilization. The author proposes a trough solar assisted biomass cogeneration system, which uses medium and low temperature trough solar energy to heat conduction oil, drives absorption heat pump to preheat water in the heating network, saves heating steam extraction and increases power output under the condition that biomass fuel and heat supply remain constant. The EBSILON professional software was used to model and simulate the case unit and integrated system, and based on this, thermodynamic characteristics such as system energy flow and energy loss were analyzed. The results indicate that: under the design condition, 1.78 MWh of solar power can be generated, the photoelectric efficiency is 20.06%, and the photoelectric conversion efficiency can reach 21.60%. Hourly simulation analysis of the whole heating season shows that the total solar power generation generated in five months of the heating period is 1124.30 MWh, and the average photoelectric efficiency is 16.49%.

Numerical simulation of thermal performance of cold plates for high heat flux electronics cooling

High heat flow density electronic components need cooling plates with strong heat exchange capacity to maintain temperature balance. To obtain better cooling performance, four different flow channel types of cooling plates are designed, including an S-type channel, Z-type channel, mosaic channel and double-layer channel. The maximum temperature of the cooling plate, outlet temperature and pressure drop under different working conditions and coolant are analyzed by numerical simulation. The simulation results show that the double-layer channel design can effectively enhance the heat transfer effect of the cooling plate and reduce the pressure drop. The maximum temperature of the cooling plate of the double-layer flow channel is 6.88 ?C lower than that of the Z-type flow channel. Moreover, increasing the inlet flow rate and lowering the coolant inlet temperature can improve the cooling performance of the cold plate, but increasing the inlet flow rate will lead to an increase in the pressure loss of the cold plate. When the coolant of the dou?ble-layer channel cooling plate is 20% ethylene glycol-water solution, the cooling performance is better than the other three coolants. Other channel cooling plates perform better with water as the coolant.

Thermal performance of wedge pile slab foundation without frost protection insulation and highly insulated slab on ground floor – first year measurements

In the Nordic countries frost insulation is necessary if the foundation is above the frost-free depth. The thermal performance of the pile foundations is between a shallow ground foundation and a frost wall foundation. The pile ends extend below the frost line to help insulate the ground beneath a building’s foundation. The ends of the piles extend below the frost line to prevent the foundation of the building from frost heaving. However, there may be a risk that the ground below the slab on ground may freeze and frost heaving may occur there. The risk of frost below the slab on ground floor and/or basement increases because increasing thickness of floor insulation remarkable influences frost insulation dimensioning. In this study a 6.5 × 17-meter size uninsulated wedge pile slab foundation with highly insulated (U=0.07 W/(m2·K)) slab on ground floor was constructed for a heated building and equipped with temperature, soil moisture, relative humidity, and heat flux sensors. Seven temperature measurement piles below the building and one for reference 8 meters far from the building reached a depth of up to 3.2 meters, which is deeper than the usual 1.4 m depth to avoid freezing in foundation design. In three places, the temperature below the insulation of slab on the ground is measured at 0.5 meters step up to 3 meters from the outer wall of the building. The first-year measurement results showed that temperature did not drop below the zero degree below the foundation and floor. Even though during winter the daily average absolute minimum temperature was -24 °C the sum of degree hours below the zero degree was -7300 °Ch. The historic 50-year absolute sum of minimum degree hours below the zero degree was -28600 °Ch. In addition to real measurement results this three-dimensional temperature sensor field helps to calibrate and validate dynamic model for temperature simulation of thermal performance of wedge pile slab foundation without frost protection insulation and highly insulated slab on ground floor.

Heat Mitigation Benefits of Urban Trees: A Review of Mechanisms, Modeling, Validation and Simulation

Modeling, validating, and simulating are three essential parts in investigating the heat mitigation benefits of urban trees (BUT). Therefore, 81 relevant studies from the last ten years are reviewed, analyzed, and summarized in this study. Three main ways for urban trees to adjust the environment are summarized, including shade creation and radiation modification, cooling effects of transpiration, and airflow blocking and modification effects. Research works are analyzed with regard to four categories: (1) heat and moisture exchange mechanisms and their mathematical modeling; (2) verification of modeling predictions based on measurements; (3) thermal performance simulation and prediction; and (4) environmental assessment and human thermal comfort analyses. Future research opportunities are discussed: (1) conduct real-time and in-depth measurements to analyze the mechanisms of heat and moisture transfer of trees in different areas; (2) develop tree radiation attenuation, airflow resistance, and transpiration models to accurately describe heat and moisture transfer processes in the urban environment; and (3) establish a three-dimensional numerical simulation method that can accurately simulate the urban thermal environment with trees. This review provides researchers with an overview and potential research opportunities on the thermal effects of urban trees.

Climatic conditions as a guideline to mass customisation in Brazilian housing

Reducing the housing deficit is a vital issue to be addressed in developing countries. Although government programmes in Brazil aim to reduce it, there is criticism regarding the housing design, especially about their poor thermal performance. Guaranteeing high levels of thermal performance in affordable housing is expected to improve occupants’ satisfaction and reduce energy consumption. Therefore, this article aims to propose a system to develop solutions for designing a housing-unit module that enables adaptation to climate, topography, and site plan, as well as flexibility regarding expansions and changes in the pattern of use. Guidelines were created to develop the adaptable housing unit framework, which was programmed in Grasshopper to allow parametric design. One of the possible compositions was simulated using EnergyPlus and Ladybug Tools to determine suitable envelope characteristics for different climates. This process relied on multicriteria analyses to determine the best solution considering cooling and heating degree hours. Thermal performance simulation results show that the envelope solution for Florianópolis differs from that for São Joaquim, even with the same shape composition. While Florianópolis has lower wall absorptance and brick walls as the best solution, São Joaquim requires insulated walls and higher wall absorptances. The main conclusion is that such a framework is more feasible than a single solution because the design might be adapted according to problems identified a priori. This outcome is expected to guide practitioners toward sustainable development, considering the vital role that affordable housing plays in Brazil.

Quantitative review on recent developments of flat-plate solar collector design. Part 1: Front-side heat loss reduction

Several studies demonstrated novel and effective design solutions for the FPC thermal performance enchantment by the front side heat loss reduction. However, these design improvements were tested under different climatic and operating conditions. This fact makes it almost impossible to compare these design improvements. The following study quantitatively analyses the current flat-plate solar collector design developments, focusing on reducing front-side heat loss. It also performs a simulation analysis to demonstrate the thermal performance improvement of the chosen design solutions for three specific applications. The literature review was performed to identify the most promising design solutions. Then, the considered design solutions were modelled using the validated detailed theoretical model of a flat-plate solar collector (FPC). Finally, the modelling results were used to perform the thermal performance simulation analysis for Würzburg (Germany) climatic conditions and constant mean fluid operating temperatures of 50, 75, and 100 °C. The simulation results indicated that applying the considered design solutions to decrease the front-side heat losses could significantly increase the FPC thermal performance. Moreover, for high-temperature applications, where the front-side heat loss is a crucial factor determining the FPC thermal performance, there is more than a significant potential for the FPC thermal performance enchantment. To sum up, our findings indicate a significant thermal performance improvement potential that could increase the application range of FPCs and make them more competitive for a broader application area.

Validated simulation of thermal performance of phase change material infused recycled brick aggregate in 3D printed concrete

Passive design solutions are important in reducing the amount of heating and cooling energy required to maintain thermal comfort inside a building, without adding to the problem of climate change. Phase change materials (PCMs) are a thermal energy storage passive design solution, with the ability to change phase and store heat at chosen temperatures. PCMs can be added to concrete to create PCM-concrete, a composite material with sensible and latent heat storage ability. The purpose of this research is to create an accurate 2D model which can be used to determine the heat transfer through 3D printed concrete (3DPC) building façades containing PCM. Two building façade wall sections are simulated in ABAQUS and validated by thermal tests – a reference 3DPC façade section, in which 64% of the natural aggregate is replaced with recycled brick aggregate (RBA-3DPC), and a PCM-3DPC façade section, containing the same replacement level of RBA but with PCM vacuum impregnated into the RBA. With the validated model, computational simulations of the thermal performance of the PCM-3DPC façade section with varying PCM melting temperatures and different façade surface colours are tested. Subsequently, a PCM-3DPC façade section with 100% replacement of natural aggregate with RBA, infused with PCM of two melting temperatures (such as 18 °C for activation in winter and 28 °C for activation in summer) is proposed for climates with large seasonal temperature changes. In addition, contrary to most studies, an iterative approach was used for modelling cavity convection and internal ambient temperature, and this approach is found to be necessary, so as not to over constrain the model with set façade and internal temperatures.

Housing Adaptations to Climate: Vernacular Settlements on the Kahayan Riverbank at Palangka Raya, Indonesia

Producing buildings that can adapt to climatic conditions is one of the notable abilities of people who improve the quality of their houses. Lake Tundai is a residential area in Palangka Raya, Indonesia, occupied by a fishing community, isolated and only accessible through the Kahayan River. People prefer wood materials for house construction, and with a largely impoverished population, they remain in those houses they have inherited from the past. However, it is an example of a village resistant to the effects of global climate change, because their houses are climate-friendly, although natural breeze is the only thermal comfort enjoyed by the inhabitants of Lake Tundai. Using thermal performance simulation on the Tundai Lake houses, this research presents four types applied to four variable elements through the Ecotect analysis program to ascertain how the houses deal with the climate. Based on the climatic conditions in Lake Tundai. Type 2 with stilts, light roof, light walls, single ventilation, and ceiling is the most suitable model condition in Tundai Lake. The research concluded in 2023 that the influence of the building floor height from the ground may affect the thermal comfort in the room. If the floor height over the water level is below 1.2 meters. This study proposes an example of housing adaptation using wood materials nearby the water.

Simulation and Field-Based Study of Thermal Performance of a Building - A Case Study

Concerns about building thermal performance and energy consumption are fast growing as they account for roughly 40% of worldwide annual energy use. Building construction in Nepal is controlled by the National Building Codes (NBC), which focus solely on structural considerations and ignore thermal behaviour. As a result, housing tends to be too much warm and too cold during summer and winter respectively due to the lack of passive heating and cooling mechanisms considered during the construction phase. The Thakle Integrated Settle (TIS), built by the Department of Urban Development and Building Construction (DUDBC) under the National Reconstruction Authority and supported by Oxfam Nepal, was the subject of this research. The building’s performance in the chosen location was analysed using a field and TRNSY simulation-based technique. Using meteorological data from Meteonorm software, the TRNSYS model was created to examine the performance in terms of internal air temperature and heating/cooling load of two buildings with different orientations, e.g., North-East (NE) and South-West (SW). According to simulation results, there is a heating demand that covers roughly 37% of the year, while cooling and comfort conditions were 32% and 31%, respectively. For NE and SW-facing buildings, heating demand was 4.10 MWh and 4.07 MWh, while cooling demand was 1.302 MWh and 1.309 MWh respectively.

Simulation and optimization of thermal performance in diverging/converging manifold microchannel heat sink

Increasing complexity of electronic devices and chips places increasingly stringent requirements on heat sinks. A novel manifold microchannel heat sink with diverging/converging channels is proposed to improve heat transfer performance. The flow and heat transfer characteristics under single-phase are investigated numerically. The effects of two key parameters, manifold inlet to outlet ratio α and channel inlet to outlet ratio β, and their combinations on the thermal-hydraulic performance are explored. The results show that, in the single parameter optimization, a moderately diverging manifold layout and a converging channel layout each have the best enhancement effect on heat transfer for given pumping power, reducing the thermal resistance by 11.1% and 13.5% than homogeneous structure, respectively. When both parameters are set as optimization variables, the parameter combinations with enhanced performance are distributed in a sloping downward band in the parameter diagram. The configuration with α = 1/9 and β = 9 has the best reinforcement effect, reducing the thermal resistance by 19.18% for a given pumping power of 5×10−4 W. In addition, the heat transfer characteristics of the optimum and original configurations under non-uniform heating flux are also investigated for application, with the optimum configuration showing better performance at both temperature level and temperature uniformity.