Local Heat Loss Research Articles

Flame characteristics and NO emission behaviors of methane/ammonia counterflow premixed flames with opposed N2 or air stream

Behaviors of methane/ammonia counterflow premixed flames and NO emission are numerically and experimentally investigated with opposed N2 or air stream by varying strain rate (ag) and equivalence ratio (ϕ). The premixed stream is 80% methane and 20% ammonia by volume mixed with air considering the utilization of ammonia by blending hydrocarbon fuels. The opposed stream is either N2 or air considering the potential application in gas turbines having single- or two-stage combustion. The simulations are conducted by increasing ag up to flame extinction for a specified ϕ and an experiment is conducted to evaluate various kinetic mechanisms. The extinction strain rate increases monotonically with ϕ with opposed air stream (AS), while increases and then decreases with opposed nitrogen stream (NS). The extinction mechanisms are explained by adopting the concepts of the local equilibrium temperature and heat loss ratio. For lean and rich mixtures with NS and lean mixtures with AS, the extinction occurs due to comparable effects of incomplete reaction and heat loss from the flame to the downstream burnt region. While for rich mixtures with AS, the extinction is attributed mainly to incomplete reaction. The contribution of thermal NO as compared with prompt NO in NO production is weak for all cases with NS and AS. The emission index (EINO) for lean and rich mixtures with NS and for lean mixtures with AS decreases monotonically with the increase of strain rate for all ϕ. Increasing equivalence ratio at a specified ag decreases NO production for lean and rich mixtures with NS and lean mixtures with AS. While for rich mixtures with AS, the EINO increases monotonically with ag. From the reaction pathway analysis, for lean mixtures, the effect of increasing ag on the reduction of NO production is attributed by weakening NH-related reaction paths, while NH2-related reaction paths change little. When ϕ increases for a specified ag with NS, NO production is reduced by weakening NH2-related reaction paths and strengthening NH-related reaction paths. For rich mixtures with AS, increasing ag increases NO production by strengthening NH2-related reaction paths.

Measurements of the local equivalence ratio and its impact on the thermochemical state in laminar partially premixed boundary layer flames

Local fuel–air equivalence ratios, gas phase temperature and CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {CO}_2$$\\end{document} mole fractions were measured by a combination of laser-induced fluorescence of nitric oxide used as a tracer and dual-pump coherent anti-Stokes Raman spectroscopy in a vertically oriented partially premixed boundary layer flame under laminar flow conditions. By embedding a secondary effusive fuel inlet into the temperature-controlled wall of a sidewall-quenching configuration, different pyrolysis rates of a wall-embedded polymer are mimicked with reduced chemical complexity and well-controlled boundary conditions. The resulting boundary layer flames were investigated experimentally and numerically. The simulation results and measurements show a very good agreement on the complex interplay between local mixing and heat losses, even though inhomogeneities of the wall inlet complicate the comparison of data. Local equivalence ratios upstream of the reaction zone reach values of up to Φ=2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varPhi = 2$$\\end{document}. Under these conditions, a clear quenching location could not be identified based on the experimental data. A significant trend toward lower temperatures and CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {CO}_2$$\\end{document} mole fractions with increasing amount of secondary fuel was found in the thermochemical state close to the temperature-controlled wall, downstream of the effusive inlet.Graphical abstract

Numerical approach to analyze fluid flow in a type C tank for liquefied hydrogen carrier (part 2: Thermal flow)

The present study aimed to analyze and compare vacuum insulation systems suitable for a type C liquid hydrogen storage tank. Multiphase thermal analysis was conducted via computational fluid dynamics, and experimental results for the boil-off rate (BOR) of a type C liquid nitrogen storage tank were obtained to verify the simulation technique. The simulation results showed a maximum error of 0.941 % compared to experimental results. Three insulation systems with superior thermal performance were selected and compared in a 3D system. The Vacuum+MLI Mylar-net insulation system showed the best thermal performance, with a result of 0.189 %/day. An analysis of the parts vulnerable to heat loss was conducted. These findings contribute to the development of high-performance insulation systems for the safe and economic transportation of liquid hydrogen. The study is an important resource for assessing insulation performance during the design phase and preventing local heat loss during operation.

A transient heat losses model for two-tank storage systems with molten salts

Concentrating Solar Power (CSP) is a proven and mature technology for energy supply. In recent years, electricity generation based on this technology has increased worldwide, to a large degree due to its high dispatchability when coupled with an energy storage system. Commercially, most plants store the energy in molten salts in a two-tank configuration. This study focuses on this storage configuration and proposes a mathematical model for the thermal losses in these tanks, both at nominal conditions and during transients. With this model at its core, a computational tool for thermal performance analysis in OpenModelica is developed. This dynamic thermal model includes the estimation of local heat loss due to assembly defects, which are heat flows that cannot be determined by theoretical modelling. The development of a semi-empirical correlation for estimating local heat loss is also presented. Simulation results showed that this local heat loss may represent a share about 40% of the total heat loss in a small-scale tank. A comparison of the characteristics of the model proposed in a previous work is also presented to establish the innovation of the model. Two thermal storage systems with different tank designs and sizes were simulated to compare the results using the present model with data available in the literature. Results show good agreement in transient thermal behaviour of heat flows, temperatures, and cooling rates when compared with data from other authors for the same tank.

Numerical study on spherical flame propagation in dispersed liquid ammonia droplets

Directly using liquid ammonia in combustion devices can simplify the fuel supply system and reduce equipment costs. However, the detailed ignition and propagation mechanisms of liquid ammonia flames have not been fully understood. This study aims to investigate the ignition and propagation of liquid ammonia flames numerically under various conditions. Spherically expanding liquid ammonia flames are studied using detailed chemistry. The effects of initial temperatures, droplet diameters, equivalence ratios, and heat fraction are investigated. The results indicate that the rapid flash boiling of liquid ammonia droplets leads to a strong local heat loss, hindering the ignition and propagation of the flame. Preheating can significantly increase the reaction rate, which compensates for the heat loss caused by phase change, allowing the flame kernel to ignite and propagate outwards. While droplet-flame interaction is present but not significant due to the rapid evaporation of liquid ammonia. The effect of droplet on the flame surface curvature is only distinguishable at conditions of large diameter. Equivalence ratio and ammonia heat fraction ratio change the amount of liquid ammonia. The more liquid ammonia, the more heat is absorbed by the phase change process, making the flame more difficult to be ignited.

Identifying two ignition modes of polymer insulated wires with continuous excess current in microgravity

Overload ignition of electric wires in microgravity has been investigated for space fire safety. Microgravity experiments from drop towers and parabolic flight have been conducted to observe the overall ignition phenomena. Two-dimensional numerical simulations were performed employing finite-rate chemistries in both condensed and gas phases. As the applied current changes, two distinct ignition modes were found in both experiments and simulations, one away from the wire and the other near the wire surface, named “spontaneous ignition” and “wire assisted ignition”, respectively. After validating ignition delay times by experiments, the simulation results were used to discuss the transition of two ignition modes. With a lower current, the spontaneous exothermic reaction at the pyrolysis gas front led to the far-distance ignition. While with a higher current, the local heat loss suppressed spontaneous ignition; meanwhile, the excessive heat from the exposed core wire caused the surface ignition. In addition, the ignition energy showed a non-monotonical increase with the applied current, where the minimum ignition energy was consumed with 5.5 A current supply implying the high fire risk of the “spontaneous ignition” regime. The control mechanisms of the ignition energy change in different stages were discussed.

Modeling Spray C and Spray D with FGM within the framework of RANS and LES

In this study, two different diesel-like igniting sprays are investigated: Engine Combustion Network (ECN) Spray C and D. In particular, this study focuses on the respective performances of the RANS and LES models to predict a turbulent, igniting spray using the OpenFOAM platform. The breakup model, discretization schemes, and case setups, including the combustion model, are kept constant in order to mitigate any potential effect on the simulation apart from intrinsic differences due to turbulence modeling. A classic κ-ε model is applied for the RANS approach, while a dynamic structure model is used to solve the momentum equation in the LES approach. The κ-ε model constants are tuned to obtain a suitable prediction of inert experiments. Both approaches exhibit a reasonable agreement with the inert experiments regarding the global spray characteristics, the liquid length, and the vapor penetration. However, the transient local properties, including the spatial distribution of mixture fraction variance and the species distributions, are not identical. For reacting conditions, the Flamelet Generate Manifold (FGM) model is adopted in both the LES and RANS simulations, using several enthalpy levels as the fourth dimension in the tabulation to account for local heat loss. The results show good agreement between the two turbulence models, in terms of liquid length, vapor penetration, and lift-off length, while a short ignition delay is registered for both sprays and turbulence frameworks. Turbulence–chemistry interaction (TCI) is considered by applying a presumed probability density function (β-PDF) to the mixture fraction, and is found to play a key role in the reproduction of species distribution in the domain.

Study of heat loss mechanism in argon-circulated hydrogen engine combustion chamber wall surface conditions

Hydrogen fuel in internal combustion engine gives a very big advantage to the transportation sector especially in solving the greenhouse emission problem. However, there are only few research discovered the ability of argon as a working gas in hydrogen combustion in internal combustion engine. The high temperature rises from the argon compression tend to result in heat loss problem. This research aims to study the heat loss mechanism on wall surface condition in the combustion chamber. Experiments were conducted to study the effects of different heat flux sensor locations and the effect of ignition delay on heat flux. Local heat flux measurement was collected and images were observed using high speed shadowgraph images. The ignition delay that occurred near the combustion wall will result in larger heat loss throughout the combustion process. Higher ambient pressure results in a bigger amount of heat flux value. Other fundamental characteristics were obtained and discussed, which may help in contributing the local heat loss data of an argon-circulated hydrogen engine in future engine operation.

Heat release and transfer of premixed propane/air flames in high g-load centrifugal force fields

Rapid combustion and propagation are crucial for energy conversion and utilization equipment, such as power plants and thrust engines. High g-load in centrifugal flow fields has been demonstrated to be able to elevate turbulent flame speed. However, more details of flame behaviors in strong centrifugal force fields still need to be investigated. This paper focuses on flame bubble behaviors and related aspects by conducting Large Eddy Simulations (LES) of high g-load centrifugal flames stabilized by a backward step in an annual combustor. A centrifugal force was produced by setting different circumference inlet velocities (0 ms/, 4 m/s, 8 m/s, 12 m/s and 16 m/s) while axial velocity was constant (12 m/s). Wall-adapting Local Eddy-viscosity (WALE) model was used as the subgrid-scale model. Flamelet Generated Manifold (FGM) model and a 31-species and 107-step propane/air reaction mechanism were used for combustion modeling. The centrifugal body force exerted on flame bubbles and cold gas parcels is found to be able to make them move oppositely in the radial direction, and thus makes the flame surface more wrinkled. This effect leads to reinforced heat exchange between hot burned gas and cold fresh mixture. The consequent results are not only that the flame propagation speed is increased and the flame zone is broadened, but also that the local heat loss is enhanced, which leads to a weaker local heat release rate and might even lead to flame extinction. Additionally, the time-averaged flame front consists of a preheating zone and a reaction zone, along with a centrifugal-force-induced heat transfer from the post-flame zone to the cold fresh mixture.

Air curtains for reduction of natural convection heat loss from a heated plate: A numerical investigation

Concentrating solar power (CSP) plants encounter inefficiencies at all stages of electricity generation. Convection from the solar-thermal receiver is a significant mode of heat loss in CSP systems, and is challenging to mitigate. This study investigates the reduction of convection losses by using a planar jet that disrupts the buoyant flow arising from the heated surface of an external CSP receiver. An isothermal flat plate with a height of 1.8 m was used to model the receiver, and a planar jet air curtain with a nozzle thickness of 3 mm was introduced near the upper edge of the wall. A computational fluid dynamics model was first validated and subsequently implemented to conduct a parametric study on the heat transfer from the isothermal plate with an air curtain varying four parameters: jet speed, jet angle, plate temperature and plate inclination. The results showed that the air curtain generates a stagnation zone adjacent to the wall which successfully reduces local convective heat losses. The effectiveness of an air curtain is defined here as the relative reduction in the local heat loss due to the air curtain, compared to the case of natural convection alone. A local maximum of 31.2% effectiveness is achieved in the stagnation zone below the jet outlet for a vertical wall with a jet speed of 2.5 ms−1 and jet angle of 45∘. The air curtain effectiveness at the stagnation region was found to decrease with increasing jet speeds, whereas the effectiveness increased near the laminar-to-turbulent transition region with increasing jet speed. Smaller air curtain angles relative to the wall resulted in lower effectiveness. A 45∘ air curtain on a vertical wall can offer performance benefits that are similar in magnitude to inclining a wall from the vertical. A higher wall temperature was accompanied by better effectiveness near the jet outlet, particularly in the stagnation region, while lower wall temperatures produced higher effectiveness further from the jet. Therefore, an air curtain can be used to reduce convective heat losses locally from a heated flat surface, including potentially when applied to CSP receivers.

Effects of vertical and horizontal heating panel on heat loss from human legs

In China’s hot summer and cold winter zone, there are cold and humid in winter. If there is no heating measure, the human body will feel less comfortable in the cold environment. The traditional HVAC system consumes a lot of energy, and it is difficult to meet the thermal comfort needs of everyone. By creating a local thermal environment around the human body, the personalized heating system can significantly improve the thermal comfort level of the human body with lower energy consumption. In this paper, it is mainly analyzing the heating effect of the heating panel on the legs of the human body by theoretically analyzing the indoor temperature of 12 °C in the hot summer and cold winter zone. For the following two working conditions: the heating panel is placed vertically on the side of the human leg and the heating panel is placed horizontally under the feet. It is calculated that when the human body feels comfortable, the heat loss is about 45 W/m2∼50 W/m2. The conclusions are as follows: (1) When the heating panel is placed vertically on the side of the human leg, the thermal comfort needs are only met when the heating panel temperature is 70 °C and the distance between the heating panel and the leg is 5 cm or 10 cm. (2) When the heating panel is placed horizontally under the feet and the temperature of the heating panel is 70 °C, the local heat loss of the human body is less than 45W/m2, and the human body feels slightly warmer.

Novel Dual Walling Cob Building: Dynamic Thermal Performance

This paper emphasizes the experimental and numerical study of new cob mixes used for insulation and load bearing wall elements. The experimental study provides complete datasets of thermal properties of the new walling materials, using cob with density ranging from 1107 kg/m3 to 1583 kg/m3 for structural walls and less than 700 kg m−3 for insulation walls. Various mixes of French soils and fibres (reed, wheat straw, hemp shiv, hemp straw, and flax straw) with different water contents are studied. The lowest average thermal conductivity is obtained for the structural cob mix prepared of 5% wheat straw and 31% of water content. The insulation mix, prepared with 25% reed and 31% water content, has the lowest thermal conductivity. Investigation of diffusivity, density, and heat capacity shows that, when thermal conductivity is lower than 0.4 W m−1 K−1, the decrease in cob density leads to better insulation values and higher heat capacity. Little variation is noticed regarding the density and heat capacity for cob mixes with thermal conductivity higher than 0.4 W m−1 K−1. Furthermore, the non-uniformity of local thermal conductivity and heat losses through the samples is due mainly to the non-uniform distribution of fibres inside the mixes inducing an increase in heat loss up to 50% for structural walls and 25% for insulation walls. Cob thermal properties are used in a comparative simulation case study of a typical house under French and UK climatic conditions. The energy performance of the conventional building is compared to a dual walled cob building, showing remarkable reduction in energy consumption as the cob walls, whilst maintaining comfortable indoor conditions without additional heating.

Assessment of virtual thermal manikins for thermal comfort numerical studies. Verification and validation

In turbulent flows as in HVAC applications, the fluctuation of air speed can affect the sensation of thermal comfort. This study is a part of a larger experimental and numerical campaign intended to evaluate the influence of the turbulence intensity at the inlet of air distribution systems on the local draft sensation and thermal discomfort for different ventilation cases using numerical simulations. For five different imposed values of turbulence intensity (0%, 3%, 10%, 30%, 50%) the local heat loss for different body parts was quantified CFD simulations were performed using a realistic model of human body along with an experimental validation with a humanoid thermal manikin. The CFD model was further exploited for several cases to evaluate the influence of turbulence intensity on the comfort indicators and local heat loss. The recorded velocity, turbulence and temperature fields allowed us to estimate the distributions of DR, PPD and PMV indexes which showed no significant changes, but correlations were found for the imposed turbulence intensity and local heat loss on different body parts, indicating the influence on thermal perception.

Add-on local sweating simulation system for a dry thermal manikin

This study develops an add-on local sweating simulation system to upgrade existing dry thermal manikins to local and sweating thermal manikins. The performance of this system was studied using a dry thermal manikin resembling a human lying on a bed with a ventilated mattress. The system comprises water-repellent porous hollow tubes to discharge water onto a diffusive fabric, as well as a motorized gear pump, DC power supply, relay module, microcomputer, and water container. Using the developed system, we maintained a cyclic steady-state for sweat generation; further, as simulated sweat, the tubes discharge distilled water over a wide area on the surface of a manikin segment covered with fabric. The local evaporative heat loss determined using the manikin roughly agreed with that calculated using the latent heat and water discharge rate, with a difference within 5 W/m2. The humidity in the bed microenvironment was increased via the add-on sweat generation system and decreased via mattress ventilation. A dry thermal manikin with an add-on system is suitable for evaluating local cooling induced by sweating. The system has high repeatability (6% standard deviation); however, the accuracy of the water discharge rate (30%) needs improvement.

Three-dimensional CFD simulation of pattern formation in a shallow packed-bed reactor for oxidative coupling of methane

Stationary or spatio-temporal patterns of catalytic reactions can cause operating challenges in shallow packed-bed reactors with large diameter to depth aspect ratios. Partial ignition patterns were observed in a pilot scale oxidative coupling of methane (OCM) reactor operating on the ignited branch near the extinction point. A three-dimensional (3D) computational fluid dynamics (CFD) model was developed for the down-flow shallow packed-bed reactor using porous media approach, with user-defined functions for heterogeneous heat transfer and Langmuir-Hinshelwood form reaction kinetics. The CFD simulation results show that, once the operating condition is nearing or beyond the extinction point (at lower feed temperature or shorter space time), 3D temperature patterns form due to either thermo-flow or thermo-kinetic steady-state multiplicity. The simulations provide insights into the pattern locking mechanism that stems from the non-linear hydrodynamic-kinetic-thermal coupling in the bed. Specific pattern observed in the CFD solution depends on perturbation sources such as unstructured space discretization, local heat loss through refractory walls, variations in catalyst activity or porosity of the packed-bed, as well as non-uniform initial conditions such as preheating, among others. The results indicate that the non-uniformity of bed physical and chemical properties (such as packing porosity, catalyst activity, or thermal properties) can dominate the pattern in practical reactor operation. Based on parametric studies, methods to mitigate pattern formation are recommended, such as more uniform incoming flow, uniform catalyst bed, uniformly preheated bed, higher catalyst activity (operating farther from extinction point), and/or higher bed thermal conductivity.

Implications of supplying district heat to a new urban residential area in Sweden

Here we analyze the cost, primary energy and CO2 implications of supplying district heat, considering different supply and return temperatures, to a new residential area in Växjö, Sweden. We explore four land exploitation alternatives consisting different types of buildings with various heated floor areas as well as occupancy densities and two levels of building energy efficiency, based on the Swedish building code and passive house criteria. The analysis shows that energy performance of the buildings and land exploitation alternatives strongly influence the annual heat demand and its profile, which steers the design of the local heat distribution network. Additionally, supply and return temperatures of district heat somewhat influence the design of the network. The distribution heat losses could be reduced by 25% and 50% if district heating systems of 65/30 °C and 50/20 °C, respectively, are used instead of a conventional 80/40 °C system. However, for the same land exploitation alternative, the local distribution heat losses are about the same whether or not the buildings are designed to meet the Swedish building code or passive house criteria, since the same pipe distance is required and the variation of pipe diameters is small. A 50/20 °C system increases electricity use to boost hot water temperature to avoid the risk of legionella bacteria, and this influences quantity of district heat supply, primary energy use and costs. Therefore, a 65/30 °C system appears to be more primary energy and cost efficient than a 50/20 °C system. Increased insulation of district heating network reduces heat losses but this is not cost effective due to increased investment cost. The results are similar whether or not the analysis is based on current energy supply or future renewable based energy supply. This study increases understanding of strategies for planning and designing new urban residential areas and their energy supply systems to reduce primary energy use as well as monetary costs, and to minimize the climate impacts of the built environment.

Spatiotemporal sweat evaporation and evaporative cooling in thermal environments determined from wearable sensors

This study aimed to provide a mobile experimental method for assessing spatiotemporal skin evaporative losses that influence human thermal states. The proposed method can be used to predict the total evaporation from skin and corresponding evaporative heat loss by combining typical climatic observations and data from wearable sensors placed on the subject’s skin over different anatomical regions. Wearable sensors can obtain humidity data, calculate local evaporation and local evaporative heat losses based on the theory of mass transfer, and then reflect the differences among individual physical characteristics. To validate the method, participants engaged in an experiment consisting of resting and a physical activity under three humidity levels. The results obtained from the proposed method are consistent with those from conventional whole-body weight measurements, thus demonstrating the effectiveness of the method to determine sweat evaporation. Furthermore, we evaluated the distribution of evaporation over the body during exercise and confirmed a reasonable agreement between the subjects’ perception and the obtained thermal states. Overall, these results offer insights on the effect of thermal environments in practical situations entailing human activity. Likewise, we outline the application of the proposed method for predicting evaporation levels to assess human thermal environments.

On the influence of wall distance and geometry for high-pressure n-dodecane spray flames in a constant-volume chamber

To isolate the effect of flame–wall interaction from representative operating conditions of an internal combustion engine, experiments were performed in a constant-volume pre-burn vessel. Three different wall geometries were studied at distances of 32.8, 38.2, and 46.2 mm from a single-hole 0.09-mm orifice diameter fuel injector. A flat wall provides a simplified case of flame–wall interaction. To mimic the division of a jet into two regions by the piston bowl rim in an engine, a two-dimensional confined wall is used. A third, axisymmetric confined wall geometry allows a second simplified comparison to numerical simulations in a Reynolds-averaged Navier–Stokes framework. As a limiting situation for a free jet, the distance from the injector orifice to the end wall of the chamber is 95 mm. Thermocouples installed in the end wall provided insights into local heat losses for reference cases without a wall insert. The test conditions were according to the Engine Combustion Network Spray A guidelines with an ambient temperature of 900 K and an ambient density of 22.8 kg/m3 with 15% O2. Flame structures were studied using high-speed OH* chemiluminescence with integrated single-shot OH PLIF and combined with pressure-based apparent heat release data to infer combustion progress and spray behavior. Soot was studied in a qualitative manner using high-speed natural luminosity imaging with integrated high-speed laser-induced incandescence. Overall, increased mixing upon interaction with the surfaces is observed to increase early heat release rate and to significantly reduce soot, with the nearest wall distance showing most effect. The flat wall gives rise to the most significant effects in all cases.

Computational Fluid Dynamics aided investigation and optimization of a tunnel-ventilated poultry house in China

Ventilation system is crucial for poultry houses to control the indoor climate and air quality. The tunnel ventilation system is widely applied for large-scale poultry buildings in China but only limited scientific researches regarding the flow pattern, temperature distribution and design criteria are available in the literature. Thanks to the fast development of computer technology, Computational Fluid Dynamics (CFD) techniques were used in present study to investigate the indoor air movement, air temperature and relatively humidity. A three-dimensional CFD model was built according to the real dimensions of a laying hen house and the model was validated by comparing the simulation results with the field measurements at 30 positions. Meanwhile, statistical analysis was performed to determine the differences between different boundary conditions regarding the agreement between measured and CFD simulated results. Optimization of air inlet configurations was performed by using the validated CFD model and it was found that the uniformity of indoor air movement could prevent excessive local convective heat losses and reduce the temperature at the end of the house. Furthermore, the air inlets placed at the middle of the side wall could significantly reduce the high temperature expected at the end of the building without using extra energy, which is especially important for large-scale poultry farms with long buildings. The performance of side-wall windows was also examined and preliminary guidance was provided to effectively regulate the indoor climate by using these windows with the help of environmental monitoring systems. The present study contributes to the understanding and design of the tunnel ventilation system used in poultry houses.

Energy Saving for the Suburban Rolling Stock

This article is concerned with the problem of energy savings and rise of comfortableness of railway rolling stock. Done analysis has shown the insufficient paying attention to the energy efficiency of suburban rolling stock. In particular, to the problem of heat comfort for passengers. For this purpose, a procedure was carried out for the thermal audit of electric trains, taking into account the prevailing array of required indicators. To determine the sites of local heat losses, there was done the thermal-imaging inspection of the electrical train ER2 series during which it was determined the local sites of heat losses and entry of cold air. Besides the passenger compartment, there were inspected the outer body liner and driver's cabin. As a result of inspection of driver's cabin, it was found the bad quality of a sealing layer for side small windows from one side. On the basis of inspection, the recommendations for elimination of found irregularities were developed.