scholarly journals The calculation of building cooling under emergency conditions to ensure their heating reliability

Vestnik MGSU ◽  
2019 ◽  
pp. 496-501 ◽  
Author(s):  
Oleg D. Samarin
Keyword(s):  
Cooling Rate ◽  
Heat Supply ◽  
Structural Characteristics ◽  
Initial Period ◽  
Residential Building ◽  
Climatic Conditions ◽  
Time Interval ◽  
Basic Equations ◽  
Building Cooling ◽  
Air Exchange

Introduction. Continuation of research in the area of premise cooling rate calculation with the aim of obtaining dependencies, which are sufficiently accurate and take into account the most of the factors essential for the problem, but at the same time having an engineering form, is still relevant. The purpose of the study is the search for a dependence of the temperature in the building premises on time in the initial period after heat supply shutdown at emergency mode. Exponential nature of this dependence is considered as a scientific hypothesis. Materials and methods. The basic equations connecting the most important components of a heat flow in a cooling room under condition of the termination of heat supply from heating devices are used and analysed in the study. A numerical model of non-stationary thermal regime of the ventilated room is implemented on the base of the solution of a differential equations system of heat conduction and heat transfer on the surfaces of the room. Results. An analytical expression is obtained for the room cooling rate when the heat supply is disconnected, which has the form of an exponential function of square root of time since the accident. The cooling time before the condensation on the inner surface of the enclosure is determined by the example of a currently existing residential building under climatic conditions of Moscow, accounting the structural characteristics of the building and normalized fresh-air flow rate. Conclusions. It is shown that the building cooling in the initial period is influenced mainly by the ratio of the heat flux associated with unorganized air exchange and the heat loss to the environment through “light” enclosure. It was found that the decrease of natural air exchange in the building cooling process leads to a certain slowdown in the decrease of temperature, but it is not decisive. It is understood that the use of airtight light opening fillers, for example, in plastic casement, under normal conditions aggravating the sanitary and hygienic situation in the premises, under emergency conditions increases the available time interval for the restoration of heat supply.

Secure and safe heat supply of residenal buildings during transional climac condions

2018 ◽  
Vol 11 (2) ◽  
pp. 149-153 ◽  
Author(s):  
O. D. Samarin
Keyword(s):  
Heat Exchangers ◽  
Heat Supply ◽  
Residential Buildings ◽  
Structural Characteristics ◽  
Heating System ◽  
Climatic Conditions ◽  
Hot Water ◽  
Heat Output ◽  
Moderate Amount ◽  
Normative Documents

An elementary arrangement of a heat supply of residential buildings with direct connection to external heating systems is considered, providing reliability of heat supply and comfort required in indoor premises in case of cold snaps after the official closure of the heating season, or before the beginning of the same, by supplying water from the return main of the heating system after the hot water heat exchangers. The basic equations are analyzed relating the heat transfer to the heating system with water temperature in the manifold, the inside air temperature and the characteristics of the heaters, with a review of possible methods of regulating the heat supply near the beginning and the end of the heating period provided taking into account requirements of normative documents of the Russian Federation. Calculations are performed to determine the amount of the main components of the heat balance of a residential building on the example of one of the standard projects used currently in the climatic conditions of Moscow taking into account the constructive structural characteristics of the building and its occupancy level. Analysis of the obtained results and conclusions regarding the appropriateness of the application of this arrangement are provided. It is established that the actual heat output of the heating system when using a chilled water network down-stream the hot water supply heat exchangers as a heat source enables to maintain the safe indoor temperature in the building, with the average daily temperature of outdoor air above +2° C in conditions of moderate amount of heat received with solar radiation. It is shown that the use of this arrangement is virtually not accompanied by additional costs, provides hydraulic resistance of the heating system and gives a system-wide effect in the form of higher electricity generation at thermal consumption when using cogeneration.

scholarly journals Review of Intelligent Control Systems for Natural Ventilation as Passive Cooling Strategy for UK Buildings and Similar Climatic Conditions

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4388
Author(s):  
Esmail Mahmoudi Saber ◽  
Issa Chaer ◽  
Aaron Gillich ◽  
Bukola Grace Ekpeti
Keyword(s):  
Control Systems ◽  
Natural Ventilation ◽  
Energy Use ◽  
Integrated Control ◽  
Climatic Conditions ◽  
Effective Control ◽  
Practical Implementation ◽  
Optimal Output ◽  
Heating And Cooling ◽  
Building Cooling

Natural ventilation is gaining more attention from architects and engineers as an alternative way of cooling and ventilating indoor spaces. Based on building types, it could save between 13 and 40% of the building cooling energy use. However, this needs to be implemented and operated with a well-designed and integrated control system to avoid triggering discomfort for occupants. This paper seeks to review, discuss, and contribute to existing knowledge on the application of control systems and optimisation theories of naturally ventilated buildings to produce the best performance. The study finally presents an outstanding theoretical context and practical implementation for researchers seeking to explore the use of intelligent controls for optimal output in the pursuit to help solve intricate control problems in the building industry and suggests advanced control systems such as fuzzy logic control as an effective control strategy for an integrated control of ventilation, heating and cooling systems.

Current Design Rules for Welding of Wind Energy Structures for Arctic Conditions

2019 ◽  
Vol 822 ◽  
pp. 452-458
Author(s):  
Sergey Lopaev ◽  
Pavel Layus ◽  
Paul Kah ◽  
Sergey Parshin
Keyword(s):  
Wind Energy ◽  
Structural Integrity ◽  
Structural Characteristics ◽  
Welding Process ◽  
Climatic Conditions ◽  
Welding Parameters ◽  
Reliable Operation ◽  
Arctic Conditions ◽  
Current Design ◽  
Standards And Guidelines

An article presents a review of current standards and guidelines in the field welding fabrication requirements for wind energy structures in arctic conditions. Extreme climatic conditions, such as Arctic, have a strong influence on the requirements for wind turbines structural characteristics, materials and fabrication methods. Special attention has to be paid for selecting steels with suitable mechanical properties, processing methods and delivery conditions. Additionally, it is highly important to select proper welding process and welding parameters, so that the structural integrity and reliable operation can be achieved.

RENEWABLE ENERGY INTEGRATION FOR HOT WATER SUPPLY AND HEATING OF BUILDINGS

2021 ◽  
pp. 3-12
Author(s):  
Yu. Selikhov ◽  
K. Gorbunov ◽  
V. Stasov
Keyword(s):  
Solar Energy ◽  
Heat Production ◽  
Heat Supply ◽  
Alternative Energy ◽  
Fossil Fuel ◽  
Heat Pumps ◽  
Climatic Conditions ◽  
Economic Feasibility ◽  
Hot Water ◽  
The Cost

Solar energy is widely used in solar systems, where economy and ecology are combined. Namely, this represents an important moment in the era of depletion of energy resources. The use of solar energy is a promising economical item for all countries of the world, meeting their interests also in terms of energy independence, thanks to which it is confidently gaining a stable position in the global energy sector. The cost of heat obtained through the use of solar installations largely depends on the radiation and climatic conditions of the area where the solar installation is used. The climatic conditions of our country, especially the south, make it possible to use the energy of the Sun to cover a significant part of the need for heat. A decrease in the reserves of fossil fuel and its rise in price have led to the development of optimal technical solutions, efficiency and economic feasibility of using solar installations. And today this is no longer an idle curiosity, but a conscious desire of homeowners to save not only their financial budget, but also health, which is possible only with the use of alternative energy sources, such as: double-circuit solar installations, geothermal heat pumps (HP), wind power generators. The problem is especially acute in the heat supply of housing and communal services (HCS), where the cost of fuel for heat production is several times higher than the cost of electricity. The main disadvantages of centralized heat supply sources are low energy, economic and environmental efficiency. And high transport tariffs for the delivery of energy carriers and frequent accidents on heating mains exacerbate the negative factors inherent in traditional district heating. One of the most effective energy-saving methods that make it possible to save fossil fuel, reduce environmental pollution, and meet the needs of consumers in process heat is the use of heat pump technologies for heat production.

scholarly journals Calculation of indoor air temperature using dimensionless parameters for integrated climate control systems

Vestnik MGSU ◽  
2021 ◽  
pp. 486-492
Author(s):  
Oleg D. Samarin
Keyword(s):  
Air Temperature ◽  
Infinite Series ◽  
Integrated Control ◽  
Dynamic Control ◽  
Residential Building ◽  
Heat Stability ◽  
Climatic Conditions ◽  
Automation System ◽  
Maximum Deviation ◽  
Climate Control

Introduction. It is noted that the improvement of the technology for calculating the thermal regime of premises in the conditions of automation of climate systems is still relevant. The aim of the work is to find a universal dependence of the air temperature in the building premises on time in conditions of a jump in heat access or heat loss for the integral law of regulating the compensatory heat flow from microclimate systems. In the form of a scientific hypothesis, we consider the statement about the power nature of such a dependence with the presence of a maximum and an asymptotic tendency to zero. Materials and methods. The study involves the use of basic equations that relate the most significant components of heat flows in rooms serviced by microclimate systems equipped with integrated controllers under conditions of abrupt changes in thermal disturbances. The method of dimension analysis is used to identify dimensionless complexes that are essential for obtaining engineering dependencies, as well as software calculation of sums of infinite series with a given accuracy, numerical solution of nonlinear equations, and the method of power series economization. Results. An analytical expression is found for changes in room temperature under integrated control of climate equipment under conditions of a jump in heat availability, which has the form of an infinite series in degrees of a dimensionless parameter that characterizes the properties of the room and the automation system. A simplified expression for the deviation of air temperature is obtained and a formula for the required control time is derived, as well as its estimation is given on the example of one residential building in the climatic conditions of Moscow. Conclusions. It is shown that the dependence of the air temperature in a room serviced by microclimate systems with integrated controllers on time is represented in a universal dimensionless form, suitable for any objects regardless of their specific characteristics. The previously discovered relationships for the moment of maximum deviation and the value of the dynamic control error depending on the air exchange of the room, the transmission coefficient of the controller and the room’s own heat stability are confirmed and refined.

Evaluating the Environmental Impact Score of a Residential Building Using Life Cycle Assessment

2021 ◽  
pp. 142-159
Author(s):  
Manish Sakhlecha ◽  
Samir Bajpai ◽  
Rajesh Kumar Singh
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Natural Resources ◽  
Impact Assessment ◽  
Environmental Impacts ◽  
Residential Building ◽  
Resource Depletion ◽  
Climatic Conditions ◽  
Construction Methods ◽  
Growing Economy

Buildings consume major amount of energy as well as natural resources leading to negative environmental impacts like resource depletion and pollution. The current task for the construction sector is to develop an evaluation tool for rating of buildings based on their environmental impacts. There are various assessment tools and models developed by different agencies in different countries to evaluate building's effect on environment. Although these tools have been successfully used and implemented in the respective regions of their origin, the problems of application occur, especially during regional adaptation in other countries due to peculiarities associated with the specific geographic location, climatic conditions, construction methods and materials. India is a rapidly growing economy with exponential increase in housing sector. Impact assessment model for a residential building has been developed based on life cycle assessment (LCA) framework. The life cycle impact assessment score was obtained for a sample house considering fifteen combinations of materials paired with 100% thermal electricity and 70%-30% thermal-solar combination, applying normalization and weighting to the LCA results. The LCA score of portland slag cement with burnt clay red brick and 70%-30% thermal-solar combination (PSC+TS+RB) was found to have the best score and ordinary Portland cement with flyash brick and 100% thermal power (OPC+T+FAB) had the worst score, showing the scope for further improvement in LCA model to include positive scores for substitution of natural resources with industrial waste otherwise polluting the environment.

Modeling the Residential Building Inventory in South America for Seismic Risk Assessment

2017 ◽  
Vol 33 (1) ◽  
pp. 299-322 ◽  
Author(s):  
Catalina Yepes-Estrada ◽  
Vitor Silva ◽  
Jairo Valcárcel ◽  
Ana Beatriz Acevedo ◽  
Nicola Tarque ◽  
...  
Keyword(s):  
Risk Assessment ◽  
South America ◽  
Structural Characteristics ◽  
Construction Materials ◽  
Residential Building ◽  
Exposure Model ◽  
Earthquake Risk ◽  
Building Stock ◽  
Building Inventory ◽  
Andean Countries

This study presents an open and transparent exposure model for the residential building stock in South America. This model captures the geographical distribution, structural characteristics (including information about construction materials, lateral load resisting system, range of number of stories), average built-up area, replacement cost, expected number of occupants, and number of dwellings and buildings. The methodology utilized to develop this model was based on national population and housing statistics and expert judgment from dozens of local researchers and practitioners. This model has been developed as part of the South America Risk Assessment (SARA) project led by the Global Earthquake Model (GEM), and it can be used to perform earthquake risk analyses. It is available at different geographical scales for seven Andean countries: Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, and Venezuela (DOI: 10.13117/GEM. DATASET.EXP.ANDEAN-v1.0).

Effective Energy Saving Research on the Air Exchange Rate of Residential Buildings in Guangzhou Based on the Software DeST-h

2011 ◽  
Vol 374-377 ◽  
pp. 430-435
Author(s):  
Wei Wei Du ◽  
Cui Cui Qin ◽  
Li Hua Zhao
Keyword(s):  
Exchange Rate ◽  
Exchange Rates ◽  
Energy Saving ◽  
Residential Buildings ◽  
Linear Regression Analysis ◽  
Functional Relation ◽  
Residential Building ◽  
Saving Rate ◽  
Air Exchange Rate ◽  
Air Exchange

Reasonable determination of indoor ventilation rates are the main content of residential ventilation designs, and can save consumption by air conditioners. Firstly, the energy saving potential of ventilation cooling technology in Guangzhou is analyzed in this paper. The cooling load of a residential building in Guangzhou with different air exchange rates is simulated by the DeST-h after indoor heating quantity of different rooms is set. The energy saving rate is analyzed, the functional relation between energy saving rate of ventilation and air exchange rate is obtained using the linear-regression analysis method. After a comprehensive consideration of various factors, including variation of energy efficiency, room volume, air outlet size, and that the maximum air exchange rates of different rooms are fixed.

scholarly journals Effects of postgrazing residue on morphogenetic and structural characteristics of Tifton 85 pastures

2016 ◽  
Vol 37 (4) ◽  
pp. 2043
Author(s):  
Wilton Ladeira Silva ◽  
Ana Cláudia Ruggieri ◽  
Ricardo Andrade Reis ◽  
Américo Garcia Silva Sobrinho ◽  
Euclides Braga Malheiros
Keyword(s):  
Structural Characteristics ◽  
Stem Elongation ◽  
Light Interception ◽  
Climatic Conditions ◽  
Leaf Length ◽  
Elongation Rate ◽  
Area Index ◽  
Structural Variables ◽  
Senescence Rate ◽  
Leaf Appearance

The ideal time to start grazing is when pastures reach 95% light interception. The use of residual leaf area index (rLAI) to time the interruption of grazing under intermittent grazing has recently been studied in forage species in different climatic conditions in Brazil. However, studies evaluating the formation and development of leaves and tillers through morphogenetic and structural variables in functional rLAI are still lacking for Tifton 85 pastures. Therefore, the objective of this study was to evaluate the effects of varying rLAI in successive grazing cycles on morphogenetic and structural characteristics of Tifton 85 pasture grazed intermittently by sheep. Morphogenetic and structural characteristics were evaluated in three grazing cycles under three rLAI conditions (0.8, 1.6, and 2.4). The regrowth interval (time taken to return to 95% light interception) of pastures increased from 21.33 to 29.66 days with decreasing rLAI. The leaf appearance rate increased at a rate of 0.02 leaves tiller-1 day-1 and the number of live leaves per tiller increased by 0.41 with decreasing rLAI. Phyllochron, leaf elongation rate, final leaf length, leaf senescence rate, and stem elongation rate decreased linearly with decreasing rLAI. The number of live leaves per tiller was lower (7.97) in the third grazing cycle, probably owing to the higher senescence rate observed that same cycle, while the other variables had higher values. The 2.4 rLAI condition promotes excessive stem elongation, reduced leaf appearance, lower number of live leaves per tiller, and increased senescence of leaves, while the 0.8 and 1.6 rLAI conditions promote desirable morphogenetic and structural characteristics, which correlate directly with forage quality. In order to avoid excessive forage losses, grazing must occur preferentially by the end of March, when climatic conditions still support the appropriate development of the plants.

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