Thermal Performance of LSF Wall Systems with Vacuum Insulation Panels

Lightweight Steel Frames (LSF) in building construction are becoming more popular due to their fast, clean, and flexible constructability. Typical LSF wall panels are made of cold-formed and thin-walled steel lipped channel studs with plasterboard linings. Due to the high thermal conductivity of steel, these LSF components must be well engineered and covered against unintended thermal bridges. Therefore, it is essential to investigate the heat transfer of the LSF wall of different configurations and reduce heat loss through walls by lowering the thermal transmittance, which would ultimately minimise the energy consumption in buildings. The effect of novel thermal insulation material, Vacuum Insulation Panels (VIP), their position on the LSF wall configuration, and Oriented Strand Board (OSB) and plasterboard’s effect on the thermal transmittance of LSF walls were investigated through numerical analysis. A total of 56 wall configurations and 112 finite element models were analysed and compared with the minimum U-value requirements of UK building regulations. Numerical model results exhibited that using plasterboards instead of OSB has no considerable effect on the U-value of the LSF walls. However, 77% (4 times) of U-value reduction was exhibited by introducing the 20 mm VIP. Moreover, the position of the VIP to the U-value of LSF was negligible. Based on the results, optimum LSF wall configurations were proposed by highlighting the construction methods. Additionally, this study, through literature, seeks to identify other areas in which additional research can be conducted to achieve the desired thermal efficiency of buildings using LSF wall systems.

Low-Emissivity Window Films as an Energy Retrofit Option for a Historical Stone Building in Cold Climate

Low-emissivity (low-E) window films are designed to improve the thermal comfort and energy performance of buildings. These films can be applied to different glazing systems without having to change the whole window. This makes it possible to apply films to windows in old and historical buildings for which preservation regulations often require that windows should remain unchanged. This research aims to investigate the impacts of low-E window films on the energy performance and thermal comfort of a three-story historical stone building in the cold climate of Sweden using the simulation software “IDA ICE”. On-site measurements were taken to acquire thermal and optical properties of the windows. This research shows that the application of the low-emissivity window film on the outward-facing surface of the inner pane of the double-glazed windows helped to reduce heat loss through the windows in winter and unwanted heat gains in summer by almost 36% and 35%, respectively. This resulted in a 6% reduction in the building’s annual energy consumption for heating purposes and a reduction in the percentage of total occupant hours with thermal dissatisfaction from 14% (without the film) to 11% (with the film). However, the relatively high price of the films and low price of district heating results in a rather long payback period of around 30 years. Thus, the films seem scarcely attractive from a purely economic viewpoint, but may be warranted for energy/environmental and thermal comfort reasons.

Historic Building Simulation of the Internal Insulation Behavior in Climate of Slovakia in a Case Study

Main topic of the article speaks about historic building renovation in Košice. Nowadays, the building is in use as puppet theatre. The theatre suffers from various disorders caused by humidity. The envelope of building has been renovated several times, however, over time, the faults return over and over. The article can be divided into two parts. The first one presents the results of moisture analysis of the support wall. The samples from the facade probes were evaluated by gravimetric method. The second part of the article discusses the interior insulation of a historic building. Internal insulation is one of the solutions to reduce heat loss of historic buildings. The use of this type of insulation brings risks that affect the thermal-humidity behaviour of the perimeter structure. These risks are assessed using a simulation model. In addition to the risks, the impact of the insulation on the original wall structure and the impact on the indoor environment were also assessed. Based on the simulation results, we can assess whether the restoration approach is appropriate in this specific case of using insulation. The study shows that the initial humidity of the perimeter wall structure is an important factor for internal insulation. Before applying the internal insulation, it is necessary to examine the moisture and material properties of the masonry.

Underfloor Heating Using Room Air Conditioners with Air Source Heat Pump in a Foundation Insulation House

A good thermal environment is important in a place where occupants stay for a long time. Since heating a house consumes a lot of energy, an energy-efficient heating method will be required. Then, by combining a heat pump and underfloor heating, there is a possibility that both thermal comfort and energy saving can be achieved. The survey was conducted on a detached house located in Nagano Prefecture, Japan. The average outside air temperature was 4.2 °C. This study investigated the indoor thermal environment, evaluated the operating performance of the heat pump, and calculated the heat load by two-dimensional analysis. More than 80% of the subjects were satisfied with the thermal environment and the neutral temperature was 18.9 °C. In the operation of the heat pump, defrost operation was confirmed, but the average COP was 2.9, and it operated efficiently. In addition, the heat loss from the foundation slab was examined. Proper insulation placement has shown the potential to reduce heat loss. In conclusion, the use of heat pumps as a heat source has been shown to be efficient even in cold climates, and this study supports the construction of new heating methods.

Numerical Study on Optics and Heat Transfer of Solar Reactor for Methane Thermal Decomposition

This study aims to reduce greenhouse gas emissions to the atmosphere and effectively utilize wasted resources by converting methane, the main component of biogas, into hydrogen. Therefore, a reactor was developed to decompose methane into carbon and hydrogen using solar thermal sources instead of traditional energy sources, such as coal and petroleum. The optical distributions were analyzed using TracePro, a Monte Carlo ray-tracing-based program. In addition, Fluent, a computational fluid dynamics program, was used for the heat and mass transfer, and chemical reaction. The cylindrical indirect heating reactor rotates at a constant speed to prevent damage by the heat source concentrated at the solar furnace. The inside of the reactor was filled with a porous catalyst for methane decomposition, and the outside was surrounded by insulation to reduce heat loss. The performance of the reactor, according to the cavity model, was calculated when solar heat was concentrated on the reactor surface and methane was supplied into the reactor in an environment with a solar irradiance of 700 W/m2, wind speed of 1 m/s, and outdoor temperature of 25 °C. As a result, temperature, methane mass fraction distribution, and heat loss amounts for the two cavities were obtained, and it was found that the effect on the conversion rate was largely dependent on a temperature over 1000 °C in the reactor. Moreover, the heat loss of the full-cavity model decreased by 12.5% and the methane conversion rate increased by 33.5%, compared to the semi-cavity model. In conclusion, the high-temperature environment of the reactor has a significant effect on the increase in conversion rate, with an additional effect of reducing heat loss.

Connect Two Crude Oil Distillation Units with One Crude Oil De-Salter in Dewania Refinery

Crude oil, which exported to refineries, already contains salt, water, and fouling crude oil received with salt content not less than 50 ppm. Dewania refinery with a capacity of 20,000 BPSD, which serves with two crude distillation units, each unit with a capacity of 10,000 BPSD, which operate without crude desalter. In an aim to reduce the effects of salts, water and, fouling associated with crude oil, two crude distillation units connected with one crude oil desalter with a capacity of 20,000 BPSD (one desalter). crude oil desalter transferred from (Daura Refinery) to Dewania refinery, in aim to reduce salt content from 50ppm to 5 ppm and mitigate water and other fouling. Crude oil desalter installed in the middle distance between two crude distillations units (90 m from each unit isometric piping). Crude oil, which is pumped by a charge pump to preheated in crude oil distillation unit with a train of heat exchangers. When the pipeline size increased from 4″ to 6″, which reduces the pressure dropped from 0.946 to 0.15 bar for each transfer pipeline and in consequence, the total pressure drop reduces from 11.011 to 10.215 bar for the whole unit. In an aim to reduce the heat dissipated from surface of transfer pipeline. Each transfer pipeline insulated with calcium silicate insulator, the thickness of insulator increased from 38mm to 50mm in an aim to reduce heat loss from −101.56 watts/m to −84.282 watts/m, which reduced temperature difference between the surface pipeline and environment from 13 to 10°C.

INVESTIGATION OF THE INFLUENCE OF THE FLOW STRUCTURE ON THE COEFFICIENT OF HYDRAULIC RESISTANCE

During the movement along a closed circuit, the working flow has to overcome a certain hydraulic resistance. Any pipeline communication has not only straight sections, but also turns, branches, for the creation of which various fittings are used. And shut-off valves are installed to regulate the flow of the working medium. All this creates resistance, so it is very important to perform a number of calculations before starting the installation of the pipeline, including determining the hydraulic resistance. This will allow to reduce heat loss in the future and, accordingly, avoid unnecessary energy consumption.

ASSESSMENT OF SAFETY OF APPLICATION OF POLYMER MATERIAL «PENOPLEX» IN LIVESTOCK

The article presents data on veterinary and sanitary and hygienic assessment of the polymer material «Penoplex». The above material is made of Styrofoam and used in many areas of production, including to reduce heat loss of livestock facilities. Cattle and pig manure was used as a contact medium with the material under study. The duration of contact with the material (exposure) was 30 days. To study the resistance of the material to disinfectants, we used: 10 % sodium hydroxide solution (80 °C); 5 % solution of soda ash (70 °C); clarified solution of bleach containing 3 % active chlorine; 40 % solution of formaldehyde; 2 % solution of hydrogen peroxide. Studies of samples of the polymer material «Penoplex» for resistance to animal secretions and disinfectants have shown that the polymer material is resistant to them. During the experiment and after its completion, the «Penoplex» material had no visually visible changes on the outer layer. The used disinfectants and the model environment did not violate the structure of the polymer material «Penoplex». A slight change in the color of the «Penoplex» was found on the 20th day of exposure to 10 % solution of sodium hydroxide with temperature of 70 °C. For sanitary and bacteriological evaluation of «Penoplex», the disk method was used. Discs with a diameter of 10 mm were prepared from the material under study; wood discs were used as a control. Studies have found that Penoplex has no effect on sanitary-indicative microorganisms and is neutral in relation to their growth, which indicates the absence of release of substances from it into the environment that can delay or stimulate the growth of test cultures. The veterinary and sanitary and hygienic assessment of the polymer material «Penoplex» is the basis to recommend it for use in the construction of livestock buildings and inclusion as an addition to the current «List of polymer materials and structures permitted for use in the construction and technological equipment of livestock facilities» in the prescribed manner.