Reduction Of Heat Load Research Articles

Effects of milk replacer feeding rate and frequency of preweaning dairy calves in the southeastern United States: Performance, abomasal emptying, and nutrient digestibility

To evaluate the effects of milk replacer (MR) feeding rate (FR) and frequency (FF) on performance, abomasal emptying, and nutrient digestibility in the southeastern United States, Holstein calves (n = 48/season) were enrolled at 8 d of age (DOA) during summer [June to August, body weight (BW; mean ± SD) = 40.71 ± 4.35 kg] and winter (November to January, BW = 42.03 ± 3.83 kg). Within season, calves were randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement including 2 FR [0.65 (low) or 0.76 kg of solid per day (high) of a 26% crude protein and 17% fat MR], and 2 FF [2× (0700 and 1600 h) or 3× (0700, 1600, and 2200 h) daily]. Calves were housed in polyethylene hutches and managed similarly throughout the trial. Milk replacer (12.5% solids) was fed to calves based on their respective treatments until 42 DOA, when MR allowance was reduced by 50% and offered once a day (0700 h) for the following 7 d until weaning. Calves remained on trial until 63 DOA. Calf starter and water were offered ad libitum. Ambient temperature and relative humidity inside and outside hutches were measured hourly. Starter and MR intakes were recorded daily. Respiration rate and rectal temperature were recorded 3 times a week. Structural growth and BW were measured weekly. Acetaminophen (50 mg/kg of BW) mixed with MR was fed to a subset of calves (0700 h, n = 10/treatment per season) on 20 DOA. Plasma was collected at 15, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 420, and 480 min after feeding, to analyze acetaminophen. The acetaminophen concentration-time curve was modeled to the first derivative of Siegel's modified power exponential equation, and the time for plasma acetaminophen to reach maximum (Tmax) was calculated to evaluate abomasal emptying rate. During the pre- (14.9-17.9 DOA) and postweaning (51.0-54.0 DOA) periods, a subset (n = 8/treatment per season) of calves was used to determine the apparent digestibility of nutrients, using chromic oxide as the external marker. Feeding 3× reduced preweaning respiration rate during summer and reduced rectal temperature during winter. Increasing FR improved BW gain and structural growth. Feeding more times per day tended to improve growth during winter but not summer. We found no effect of treatment on nutrient digestibility. Increasing FR had no effect on Tmax during winter but tended to delay Tmax of plasma acetaminophen during summer. Regardless of season, increasing FF lowered Tmax of plasma acetaminophen. In conclusion, increasing FF accelerated abomasal emptying and might reduce heat load of preweaning dairy calves but improved growth only during winter. Increased MR allowance improved growth in both seasons but delayed abomasal emptying only under heat stress conditions.

An Assessment of Heating Load Reduction by a Solar Air Heater in a Residential Passive Ventilation System

In this paper, the authors examined the technology to maximize the use of renewable energy. Passive ventilation systems are expected to reduce the energy consumption of the fan and the maintenance burden. In addition, the wall-mounted solar air heater can supply thermal energy without using any energy at all. Therefore, this paper presents a “passive ventilation system with a solar air heater” that combines a passive ventilation system with the solar air heater to preheat the air. This system can reduce the ventilation load. To evaluate the solar air heater performance in a real environment, we developed a simulation for calculating the heat collection capacity of the solar air heater, and then the system was implemented in a real building for verification. The simulation performs hourly unsteady calculations, allowing for accurate evaluation of the annual simulation. Based on the measurement results, the effects of heating load reduction and prediction methods are presented. The solar air heater reduced the monthly ventilation load by up to 50% or more, and by at least 15%. It was also confirmed that there was a high correlation between the actual measurements and the simulation results.

Control-oriented thermal network models for predictive load management in Canadian houses with on-Site solar electricity generation: application to a research house

This paper presents a methodology for development of control-oriented thermal RC network models for optimized HVAC load management in typical electrically heated single-family two-storey detached houses in Québec, assuming that there are three zones and it is equipped with photovoltaics and battery storage. Using data from an unoccupied research house, two 3rd order RC networks are developed and calibrated. One model (3C6R network) assumes that each floor is a separate thermal zone, and the other model (3C7R network) assumes that the south-facing zone and the north-facing zone of the building are separate zones. Application of model predictive control with both developed models results in an average 12.1% reduction in the daily heating load, 19.8% reduction in the total daily electricity imported, 68.1% reduction in the peak demand, 67.0% reduction in the energy cost, and 13.4% increase in the self-consumption of on-site generated solar electricity compared to a traditional reactive controller.

INTEGRATION OF THE HEAT EXCHANGE PROCESS OF POWER PLANT

Renewable energy sources (RES) are not limited by geologically accumulated reserves. Their use and consumption will not lead to the inevitable depletion of the Earth's reserves, and they do not pollute the environment. The main motive for the accelerated development of renewable energy in Europe, the United States and many other countries is concern for energy independence and environmental safety. Thus, the EU has adopted a program to achieve the contribution of renewable energy sources to the energy balance by 2020 up to 20%, and by 2040 – up to 40%. Renewable energy is characterized by versatility and diversity. In the list of tasks arising in the implementation of renewable energy (RE) projects (except technological and technical), there are issues of assessing the possibility and efficiency of using RES for energy supply to the regions. At the same time, it should be borne in mind that often the user is interested in comprehensive assessments for various types of energy sources. In specific regions, the most effective can be either the use of hybrid power plants, or the creation of thermal power plants using various types of renewable energy. In connection with the complexity of this problem, as well as the geographic “regionality” of renewable energy, the topic of this article becomes possible and relevant. A heat and power plant is proposed for supplying: electricity, hot water, hot air and heating, in which, together with a wind power generator, a double-circuit solar installation, a heat pump, electricity and heat accumulators are used. This installation allows to reduce the cost of heat energy by reducing material consumption and costs of equipment used, to save fossil fuel; produce electricity and supply the surplus to the state power grid; reduce heat load and environmental pollution.

Heating load reduction characteristics of passive solar buildings in Tibet, China

Heating load reduction characteristics of passive solar buildings in Tibet, China

Steady-state sustainment of divertor detachment with multi-species impurity seeding in LHD

Multi-species impurity seeding is an advanced operation scenario to mitigate the divertor heat load for the realization of future fusion reactors. In the large helical device, divertor detachment is successfully sustained using higher-Z (krypton, Kr) and lower-Z (neon, Ne) superimposed seeding. Emission from Kr impurities is drastically enhanced if it is followed by Ne seeding. Plasma radiation can be enhanced even at the upstream region in the edge plasma compared with Ne only seeded plasmas with suppression of impurity accumulation toward the central plasma. The characteristics of divertor heat load reduction and energy confinement are comparable between the Kr + Ne seeding and Ne only seeding under the same radiation fraction. However, while the detachment in Ne only seeding is transient, the detachment in Kr + Ne seeding is stable. It indicates that multi-species impurity seeding can be competitive for steady-state operation although further investigation is desired about the balance between divertor heat load reduction, impurity screening, and confinement degradation. The Kr emission enhancement is strongly affected by electron density and temperature at the last closed flux surface resulting in impurity penetration.

Study on Passive Heating Involving Firewalls with an Additional Sunlight Room in Rural Residential Buildings.

With the growth in China’s economic GDP, energy consumption has increased year by year. The energy demand of rural residential buildings is 223 million tons of standard coal equivalent, accounting for 24% of the national energy demand. Therefore, an energy-saving design for rural residences is necessary. This research took the traditional residences in southern Shaanxi as the research object and combined the cooking methods in southern Shaanxi with solar heating, proposing a sunlight heating system with an additional firewall. The system is composed of a firewall system and a sunlight system. The combination of the two systems prolongs the heating time and makes up for the lack of intermittent heating. The firewall principle involves using the heat generated by cooking through the heat storage and heat release capacity of the wall, and using the principle of heat radiation and convection to increase the indoor temperature. Meanwhile, the principle of the additional sunlight room involves using the external facade of the building to establish an additional sunlight room, by absorbing the heat radiation of the sun and using the principle of heat transfer from the wall. The rapid loss of indoor hot air is avoided, the heating time is prolonged, and part of the heat is retained, thereby improving the heating efficiency. A model was established based on the typical residential model in southern Shaanxi, and the presence or absence of solar radiation on the wall was used as the research variable. Using ANSYS software to simulate the analysis, it is concluded that the firewall–sunlight system can extend the heating time and meet the continuous heating demand, and the heating effect is better than that of the firewall heating system alone. When the walls have solar radiation, the annual heat load reduction rate of the buildings under the new system is 20.21%. When the walls do not have solar radiation, the annual heat load reduction rate of the buildings under the new system is 8.56%.

Development of an indoor air purification system to improve ventilation and air quality

Novel types of an air purification system for improving indoor air quality (IAQ) and ventilation by reducing carbon dioxide (CO2) concentration were assessed in office buildings in India. This study provides an evaluation of a control system that reduces toxic gases in indoor spaces using the synthesized filter media. The reduction potential of CO2 levels of the control system, for different air handling unit (AHU) capacities, were compared. Experimental studies and in-situ evaluation has been done using the air purification system. Ventilation rates and CO2 concentration are monitored before and after the installation of the purification system. The results of the investigation indicated CO2 concentrations were reduced by more than 40% with the purification system. Fresh air intake to maintain the desired ventilation rates has been reduced to more than 50%, further reduce heat load. Ventilation flow rates were achieved with this air purification system. This system has the potential aspiration in controlling the CO2 levels in mechanically ventilated buildings. CO2 concentrations were brought down to permissible limits and maintained further without introducing fresh air into the system. Based on the results, assessment of the air purification system is a crucial and wide range of applicability in indoor environments to reduce cooling costs.

Simulation of Green Building Materials Uses and its Environmental Impacts: Case of Jordan

Construction is one of the most important factors affecting the environment such as global warming and carbon dioxide emissions. In addition, it represents 40% of the consumption of energy resources around the world. Jordan is one of the countries that suffer greatly from this aspect. In this research, a simulation was conducted of a multi-use building located in a university in Jordan using the ArchiCAD program, which helps us to accurately determine the construction location and obtain the results of materials and strategies that were applied to the building. Thermal insulation materials were used to show the effectiveness of their impact on the temperature difference per unit of heat flux needed to sustain one unit of heat flux (R-value) for the building. Shading means were also applied to the building’s glass facades that reduce heat loads and help the heating, ventilation, and air conditioning (HVAC) system inside the building. Finally, it was shown the difference in the environmental impact of a building that uses 100% solar energy and emits zero CO2 emissions. While a building that uses 50% solar energy and 50% oil energy emits a high amount of CO2. It becomes clear that the increasing use of green building tools helps greatly in facing the problems of the environment and the consumption of energy resources.

The influence of aspect ratio on the thermal performance of a cryogenic pulsating heat pipe

• Cryogenic pulsating heat pipes perform best with large vertical to horizontal ratio. • Aspect ratio dependence of thermal resistance is characterized for a helium PHP. • The major thermal resistance for a helium PHP occurs at the wall – fluid interface. • Method provided to reduce heat load and orientation sensitivity for a hydrogen PHP. Pulsating heat pipes (PHPs) are expected to serve as a significant design component for the thermal management of superconducting magnets and various cryogenic space applications, including cryogen storage tanks and low temperature detectors on telescopes. A growing body of data is accumulating regarding the performance of cryogenic PHPs, including operation with helium, hydrogen, neon, and nitrogen, and the notable dependence on their orientation with respect to gravity. However, in view of the expectation that the thermal path between a low temperature heat source and the corresponding cryocooler will involve a convoluted route including vertical, horizontal, and sloping segments, we have begun a systematic study regarding the influence of the vertical-to-horizontal aspect ratio of a PHP on its thermal performance. Although various studies available in the literature characterize the performance of completely vertical or completely horizontal PHPs, this study quantitatively displays the relative impact of the vertical and horizontal segments on the performance of a mixed orientation PHP. This systematic investigation is the first of its type to characterize the influence of the vertical-to-horizontal aspect ratio of a PHP on its thermal performance. Data gathered with both helium and hydrogen filled PHPs including five different aspect ratios confirm the expectation that vertically dominated geometries perform better than horizontally dominated geometries. Minimum thermal resistance values ranging from 1.5 K/W to 20 K/W for the 1-meter-long PHPs, with aspect ratios varying from 4:1 to 1:4, are reported as a function of heat load, fill ratio, and fluid type. Here the aspect ratio is defined by the length of the vertical adiabatic section divided by the length of the horizontal adiabatic section. The results with the hydrogen PHP demonstrate that a fill ratio of 70% significantly reduces the influence of orientation and heat load on the PHP’s thermal resistance. The combined results provide valuable guidance for their application as heat transfer components in superconducting magnets and various cryogenic space applications.

Energy performance evaluation of heat storage of calcium sulfate hemihydrate composite with fine aggregate based on paraffinic phase change material

Calcium sulfate hemihydrate has been used as a building material because of its economical and non-combustible characteristics. By applying a heat storage material to a calcium sulfate hemihydrate composite (CSHC), the building energy consumption can be reduced. In this study, a CSHC with a high heat storage capacity was prepared using fine aggregates based on paraffinic shape-stabilized phase change materials (Fa-PSSPCMs) with exfoliated graphite nanoplatelets as stabilizing additives. The heat storage CSHC (Hs-CSHC) was prepared by mixing Fa-PSSPCM and calcium sulfate hemihydrate powder with water and then casting the mixture as boards using molds. For the Hs-CSHC containing 30 wt% Fa-PSSPCM, the latent heat capacities during heating and cooling were 46.39 and 44.28 J/g, respectively; its phase transition occurred at 20–35 °C. Based on analysis results, the Hs-CSHC exhibited acceptable chemical stability and high thermal performance, including a considerable latent heat capacity. The peak temperatures of Hs-CSHCs were approximately 1–2 °C lower than those of the plain CSHC. Moreover, compared with the plain CSHC, the Hs-CSHC with 30 wt% Fa-PSSPCM exhibited a time lag effect exceeding 720 min. In the energy simulation analysis, an 8.18% maximum cooling energy reduction was observed when the Hs-CSHC with 30 wt% Fa-PSSPCM was used. However, the effect of heating load reduction was insignificant due to the low outside temperature. Therefore, when a phase change material is utilized in a building, the phase change temperature and heat storage performance must be considered.

Development of an Indoor Air Purification System to Improve Ventilation and Air Quality

Novel types of an air purification system for improve indoor air quality (IAQ) and ventilation by reducing carbon dioxide (CO2) concentration was assessed in office buildings in India. This study provides an evaluation of a control system that reduces toxic gases in indoor spaces using the synthesized filter media. Reduction potential of CO2 levels of the control system, for different air handling unit (AHU) capacities was compared. Experimental studies and in-situ evaluation has been done using the air purification system. Ventilation rates and CO2 concentration are monitored before and after the installation of purification system. The results of the investigation indicated CO2 concentrations reduced more than 40% with the purification system. Fresh air intake to maintain the desired ventilation rates has been reduced to more than 50%, further reduce heat load. This system has the potential aspiration in controlling the CO2 levels in mechanically ventilated buildings. CO2 concentrations brought down to permissible limits and maintained further without taking the fresh air. Based on the results, assessment of the air purification system is crucial and wide range of applicability in indoor environments to reduce cooling cost.

Comparative analysis of shade and underlying surfaces on cooling effect

Urban greenspaces showed the potential to lessen the urban heat island effect. However, a detailed understanding on the mechanisms of different components of greenspaces such as grass surfaces, trees or a combination of grey and green infrastructure on reducing heat loads at local and city scale and different weather conditions is still limited. We designed a small-scale experiment within the sub-urban area Freising, close to Munich in Germany during hot summer days of the year 2020 including wet and dry spells. We investigated surface energy balance and the human thermal comfort measured in terms of physiological equivalent temperature (PET). Six sites including grass lawns and paved surfaces, with or without the shade of trees and buildings were selected. Significant positive relationships between surface (ST) and air temperature (AT) were detected both for grass and paved surfaces; however, the relationships were stronger during the wet spells compared to dry spells and for grass surfaces compared to paved surfaces. Moreover, PET was more strongly related to ST compared to AT. Overall, shade reduced 15 °C, 2 °C and 13 °C of ST, AT and PET respectively compared to sunny sites. The differences between sun and shade were steeper over the grass surfaces and during the wet spells when the grass surfaces lost more than 1.5 L m−2 d−1 of water. In contrast, sensible heat fluxes between grass and paved surfaces were not different during the dry spells. Moreover, compared to the building shade, tree shade further reduced AT by 0.6 °C and 0.4 °C during wet and dry spells, but PET by 1 °C and 1.6 °C during wet and dry spells respectively. Our results underline the importance of both shade and grass surfaces in reducing the urban heat loads, in particular, the added benefits of tree shade during the summer droughts.

Observations of visible argon line emissions and its spatial profile from Aditya-U tokamak plasma.

The spectroscopic studies of medium and high Z impurities have been the subject of interest in fusion research due to their role in mitigating plasma disruption and reducing heat load on the plasma facing components. Line emissions from these impurities provide the rotation velocity and ion temperature measurements along with the understanding of the overall impurity behavior in plasma. In the Aditya-U tokamak, the spatially resolved Ar II line emissions have been observed using a high resolution multi-track spectroscopic diagnostic consisting of a 1m Czerny-Turner spectrometer coupled with a charge coupled device (CCD) detector using seven lines of sight viewing plasma tangentially along the toroidal direction. The spatially resolved Ar II lines at 458.96nm have been observed. The singly ionized Ar emission peaks at the radial location of ρ = 0.8 of the plasma having a minor radius of 25cm. Moreover, a 0.5m UV-visible spectrometer coupled with a CCD detector and having a line of sight passing through the plasma midplane from the radial port was used to record visible Ar survey spectra within the 670-810nm wavelength range, and all these lines have been identified for further analysis.

Evaluation of shape-stabilization phase change material sheets to improve the heating load reduction based on the indoor application method

The effectiveness of the phase change material (PCM) application method was measured in three identical test huts using a shape-stabilized phase-change material (SSPCM) sheet made of paraffin-based PCM. Based on these results, the accuracy was verified by comparing the measured values with the calculated values using each PCM model in EnergyPlus and ExTLA (Excel-based Thermal Load Analysis) software. Annual loads were simulated under various conditions to optimize the efficiency of the SSPCM sheets. A similar reduction in heating load was observed, regardless of the installation area until the capacity of the SSPCM sheet reached a certain value. However, above this value, the efficiency increased or decreased depending on the installation area. This shows that there is an optimum capacity according to the installation area of the PCM. To evaluate the performance of the PCM according to the shape of the building, a target building and climate were selected using the ASHRAE standard (90.1 and 169), and the heating load was simulated under the same conditions. When the volume of the building and the size of the window receiving solar radiation were constant, it was confirmed that the shape of the building did not significantly affect the heating load compared to the installed capacity and area of the PCM. However, depending on the installation area, there was a difference in annual heating loads up to approximately 12%. This study confirmed that there are optimum installation capacities and areas that maximize the efficiencies of PCMs.

Analysis of the effects of thermal anchors on the reduction of the parasitic load to the EU-DEMO TF coils

The design of the superconducting magnet system of the EU-DEMO tokamak reached the end of the pre-conceptual design phase, and a careful investigation of the parasitic heat load from the room-temperature environment is needed. A possible route for the parasitic heat to enter the toroidal field (TF) coils is by conduction through their Gravity Supports (GSs), which provide mechanical support to the TFs, the Vacuum Vessel (VV) and attached coils, acting as a thermal bridge to the TF casing. A thermal anchoring of the GS using Supercritical helium (SHe) at 4.5 K, re-routing a fraction of the coolant from the TF casing cooling loop, downstream of the casing, is addressed in this study. A 3D thermal model is developed for a plausible design of the EU-DEMO GS, coupled to fluid lines that account for the active cooling by SHe. The effect of the location of the Thermal Anchor (TA) at different heights of the GS plates is investigated parametrically and the beneficial reduction of the parasitic heat load to the TF coil is demonstrated. The reduction of the static heat load to the TF winding pack, when the TA is enabled, is computed and discussed.

ENERGY EFFICIENCY OPTIMIZATION OF THE OPERATING ROOM DUE TO THE DISPOSITIONAL LOCATION

Clean rooms, including operating rooms, are energy-intensive. During their operation, the concentration of particles in the air, air temperature and humidity are strictly monitored. HVAC systems in the operating room are subject to high demands on maintaining a stable heat and humidity microclimate, as well as particle concentrations within the permitted range. To cover heat losses and heat loads of the building, it is necessary to dimension ventilation equipment with high outputs and high energy consumption. By suitable optimization of the dispositional location of the operating tract in the building and the use of suitable thicknesses of insulating material, it is possible to reduce the performance requirements for the HVAC system, which significantly reduces energy consumption. Heat loss and heat load of the operating tract were evaluated using TechCon software. The performance values of the heaters and coolers for the HVAC units were calculated in the VentiCad design software. The optimization indicates a significant reduction in heat loss and heat load, as well as a reduction in the required temperature of the air supplied to the room by more than 10°C.

Cooling/heating load management in educational buildings through course scheduling

This paper presents a comprehensive educational model considering share resources among several departments bounded to educational limitations for optimizing energy consumption. The thermal model calculates the load based on the ambient temperature to minimize the user's knowledge of the building's thermal model. It determines the percentage reduction of the building's heating load in case of a change in room temperature, a term's start date, and sharing classes compared to standard curricula. It employs linear Boolean optimization. Class planning is carried out concerning minimizing energy use, students' preferences, charts, educational constraints, professors' schedules, classes' numbers, and shared resources.Optimal timetabling influences on the heating load for Shiraz University's second engineering building complex are analyzed, used by Mechanical Engineering, Computer Engineering departments, and Auditorium. The effects of three scenarios and two situations on energy consumption are quantified. The results indicate the best curriculum is not affected by the scenarios. A two-week early beginning and a temperature of 23C of classes reduce energy consumption by over 50%. In deploying the optimal timetabling, the potential of diminishing the heating energy consumption is about 12% compared with conventional timetabling. Sharing resources do not always lead to a decrease in energy use, but this activity can slide it by 2.5%. These results are aligned with commercial software's outcomes.To tackle the obstacle of the computational load, reducing a matrix's dimensions is implemented. It cuts down the number of decision variables, unequal and equal constraints from 90.8%, 99.97%, and 57.81%, respectively.

Applicability of phase change material according to climate zones as defined in ASHRAE standard 169-2013

The improvement of the heating load reduction effect through indoor temperature stabilization and the possibility of applying phase change materials (PCMs) in various climates were examined. The indoor temperature and heat flow of each wall are measured in three identical test huts using a shape-stabilized phase-change material sheet made of a paraffin-based PCM. The results obtained are compared with calculated results using a PCM model fabricated basing a specific heat to verify the accuracy. The annual heating load reduction is confirmed by conducting simulations of 429 cases in various conditions of PCM capacity, building shape, and installation area for representative cities in each climate zone of ASHRAE standard 169–2013. In addition with this result, the relationship among the PCM installation method, building form, and climate factors are analyzed to obtain a correlation equation for annual heating load reduction. Comparing the simulation results and correlation equation results of the annual heating load reduction rate, it is confirmed that the error of the two results is below 2.7%, and the coefficient of determination is above 0.8. This correlation equation can be a measure of the approximate heating load reduction effect due to the PCM installation and the performance of indoor application methods without complex simulations early in the design or before the construction of the PCM.

Using shell-type tuyeres at Pierce–Smith horizontal converters of the Nadezhda Metallurgical Plant

Since 2015 the processing capacity reconfiguration at the Polar Branch of MMC Norilsk Nickel (hereinafter PB) sets new goals for conventional pyrometallurgical processes of smelting and converting. The design flowsheet of Kolesnikov Nadezhda Metallurgical Abstract: Plant (hereinafter NMP) provided for «cross-converting» when copper matte was first processed in one converter to produce blister copper followed by nickel matte processing to yield copper-nickel converter matte bypassing the discharge of dry coagulated slag. This flowsheet allowed for converter heat balance optimization, decreasing the formation of refractory reverts and significant extension of the converter campaign. PB Nickel Plant shutdown resulted in copper processing elimination at NMP and switching the converters to the conventional nickel converting flowsheet. In turn, it gave rise to the need for solutions to extend converter campaign while maintaining the possibility to process large amounts of nickel slag from the second converting stage at the PB Copper Plant. For this purpose the series of lab experiments were carried out to develop the technology and design documentation for the system to supply oxygen-enriched air (up to 45 %) to horizontal converters using shell-type tuyeres. In addition, literature data were analyzed on this topic along with the experience of smelters in this area. Process design calculations were done. The efforts were taken in cooperation with the PB engineering personnel and Laboratory of Pyrometallurgy of LLC «Gipronickel Institute». The use of reduced diameter shell-type tuyeres to inject the oxygen-air mixture was found to decrease the converter blowing and off-gas volumes. The decline in off-gas quantity leads to reduced heat load on the converter mouth and flue duct system, as well as to lowered converter dust entrainment. The use of oxygen-enriched blowing implies the higher smelt heating rate. Excess heat compensation requires timely charging of cold reverts and flux. In emergencies (if cold reverts are not available) the oxygen content of the blowing has to be reduced until switching over to air blowing. The series of the above efforts will offer a possibility to use the shell-type tuyeres keeping the converter off-gas temperature at the current level. Thus continuous monitoring and efficient control will ensure the off-gas temperature and volume at the inlets of gas cooling and cleaning systems not exceeding the limiting values. The introduction of the reduced diameter shell-type tuyeres for air-oxygen mixture injection does not require any upgrade of the existing gas cooling and cleaning systems. Moreover, switching to these tuyeres will reduce gas load on the flue duct system and heat load on the water-cooled dust cap, lower dust entrainment and non-recoverable dust losses after the gas cleaning system.