AIR INFILTRATION AND ROOM HEAT LOSS THROUGH WINDOW OPENINGS

2016 ◽  
Vol 6 (3) ◽  
pp. 10-16 ◽  
Author(s):  
Vladimir I. VESNIN
Keyword(s):  
Heat Loss ◽  
Natural Ventilation ◽  
Heating System ◽  
Hydraulic Loss ◽  
Cooling Process ◽  
Transfer Resistance ◽  
Factors Affecting ◽  
Air Infiltration ◽  
Exchange Processes ◽  
Discontinuous Mode

The research of cooling processes of a building, when heating system is operating in discontinuous mode, is carried out. Factors affecting temperature decrease rate are analyzed. Influence of cold air infiltration on heat exchange processes is shown. Methods of aerodynamic calculations of natural ventilation are specified. Method of pressure determination in-building, taking into account infiltrative air hydraulic loss, is proposed. Cooling process with air infiltration is calculated. Infiltration increases clinograde by 0.4-1°C per hour. Existing materials of heat transfer resistance through fiberglass windows constructions are compiled. Practical proposals for reducing of air infiltration and heat loss through openings are made.

Factors Affecting Urea Granulation Tower Simplification of Ventilation

2014 ◽  
Vol 501-504 ◽  
pp. 2293-2296
Author(s):  
Li Li Wang ◽  
Guo Zhong Wu ◽  
Dong Li
Keyword(s):  
Phase Transition ◽  
Mechanical Ventilation ◽  
Natural Ventilation ◽  
Second Step ◽  
Melt Crystallization ◽  
Cooling Process ◽  
Granulation Process ◽  
Cold Air ◽  
Factors Affecting ◽  
Cooling Stage

Currently, most of the domestic fertilizer unit, granulation tower basically using natural ventilation, granulation tower granulation process is ejected molten urine through the nozzle to cool down after melt crystallization (phase transition), cooling 3 process[1]. The beginning step is cooling stage of liquid urea. The second step is liquid urea into solid urea particles. The last step is solid urea paticles cooling process with long drop distance. In the process of landing urea crystals, the releasing heat is taken into the cold air. The average air rate of natural ventilation in the tower is 0.4-0.8m/s. And the air rate of mechanical ventilation prilling tower is 0.6-1.2m/s. Landing time of urea particles from nozzle to Scraper is about 5-10m/s.

scholarly journals HEAT MODES OF THE HEATING NETWORK IN WARMING BUILDINGS

2020 ◽  
Vol 1 (154) ◽  
pp. 159-164
Author(s):  
A. Aleksahin ◽  
A. Boblovskey ◽  
К. Zhariy ◽  
J. Sidorenko ◽  
М. Skorik
Keyword(s):  
Energy Saving ◽  
Heat Loss ◽  
Heat Supply ◽  
District Heating ◽  
Heating System ◽  
Heat Losses ◽  
Transfer Resistance ◽  
Maximum Heat ◽  
Heating Systems ◽  
Network Water

The results of calculations of heat losses by network pipelines for heating of idealized groups of buildings during insulation of structures are presented in the work. Formulas for estimation of heat loss reduction by heat conduits are proposed depending on the efficiency of energy saving measures for construction and the law of change of network water costs along the length of the heat conduit, which is determined by the network configuration. The purpose of this work is to evaluate the influence of the hydraulic characteristics of the branches of the heating network on the magnitude of heat losses during transportation of the coolant by pipelines of the distribution network to buildings. Idealized groups of buildings with the same number of objects and the same maximum heat consumption for heating of a separate building are considered. For district heating systems, the efficiency of implementing energy-saving measures for buildings is determined not only by the reduction of heating costs, but also by the change in operating costs for the microdistrict heating network, which is caused by the reduction of heat carrier costs and heat losses by heating system pipelines. The magnitude of the heat loss depends on the method of laying the networks, the parameters of the pipeline insulation, the temperature of the coolant, and the environment. In the case of selective insulation of the buildings of the selected group of buildings, the location of the insulated building is significantly influenced by the amount of heat losses by the pipelines. In case of centralized heat supply, a fragment of the construction load decrease due to the insulation of buildings and the reduction of the network water temperature in the space heating devices causes the reduction of heat losses by the pipelines of the distribution thermal networks. The magnitude of the reduction of heat losses by heat pipelines is determined by the degree of efficiency of insulation of buildings, the nature of changes in the cost of the coolant along the length of the branch of the thermal network and practically does not depend on the magnitude of the heating load of buildings. Keywords: centralized heat supply, centralized heating systems, energy saving, heat transfer resistance, enclosing structures, coefficient of efficiency of building insulation, distribution thermal networks, heat loss by pipelines.

HEAT LOSS ANALYSIS AND OPTIMIZATION OF HOUSEHOLD SOLAR HEATING SYSTEM

2019 ◽  
Vol 50 (7) ◽  
pp. 659-670 ◽  
Author(s):  
Jieyuan Yang ◽  
Jinping Li ◽  
Rong Feng
Keyword(s):  
Heat Loss ◽  
Heating System ◽  
Solar Heating ◽  
Loss Analysis

scholarly journals Multi-criteria decision making for a large heating system with heat loss

2020 ◽  
Vol 1565 ◽  
pp. 012035
Author(s):  
T I Korotkova ◽  
S A Kolesnik ◽  
B A Garibyan ◽  
S Yu Luneva ◽  
Ya V Kuzmina
Keyword(s):  
Decision Making ◽  
Heat Loss ◽  
Heating System ◽  
Multi Criteria Decision Making ◽  
Large Heating

scholarly journals Impact of Air Infiltration on IAQ and Ventilation Efficiency in Higher Educational Classrooms in Spain

2021 ◽  
Vol 13 (12) ◽  
pp. 6875
Author(s):  
Irene Poza-Casado ◽  
Raquel Gil-Valverde ◽  
Alberto Meiss ◽  
Miguel Ángel Padilla-Marcos
Keyword(s):  
Natural Ventilation ◽  
Well Being ◽  
Cold Season ◽  
Climate Conditions ◽  
Air Infiltration ◽  
Ventilation Efficiency ◽  
Educational Buildings ◽  
Set Up ◽  
Total Volatile Organic Compounds ◽  
The Impact

Indoor air quality (IAQ) in educational buildings is a key element of the students’ well-being and academic performance. Window-opening behavior and air infiltration, generally used as the sole ventilation sources in existing educational buildings, often lead to unhealthy levels of indoor pollutants and energy waste. This paper evaluates the conditions of natural ventilation in classrooms in order to study how climate conditions affect energy waste. For that purpose, the impact of the air infiltration both on the IAQ and on the efficiency of the ventilation was evaluated in two university classrooms with natural ventilation in the Continental area of Spain. The research methodology was based on site sensors to analyze IAQ parameters such as CO2, Total Volatile Organic Compounds (TVOC), Particulate Matter (PM), and other climate parameters for a week during the cold season. Airtightness was then assessed within the classrooms and the close built environment by means of pressurization tests, and infiltration rates were estimated. The obtained results were used to set up a Computational Fluid Dynamics (CFD) model to evaluate the age of the local air and the ventilation efficiency value. The results revealed that ventilation cannot rely only on air infiltration, and, therefore, specific controlled ventilation strategies should be implemented to improve IAQ and to avoid excessive energy loss.

scholarly journals Indoor Climate Performance in a Renovated School Building

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2827
Author(s):  
Pavla Mocová ◽  
Jitka Mohelníková
Keyword(s):  
Indoor Environment ◽  
Natural Ventilation ◽  
Carbon Dioxide Concentration ◽  
Heating System ◽  
Climatic Conditions ◽  
School Building ◽  
Ventilation Strategy ◽  
Indoor Climate ◽  
Microbiological Testing ◽  
Indoor Comfort

Indoor climate comfort is important for school buildings. Nowadays, this is a topical problem, especially in renovated buildings. Poorly ventilated school classrooms create improper conditions for classrooms. A post-occupancy study was performed in a school building in temperate climatic conditions. The evaluation was based on the results of long-term monitoring of the natural ventilation strategy and measurements of the carbon dioxide concentration in the school classroom’s indoor environment. The monitoring was carried out in an old school building that was constructed in the 1970s and compared to testing carried out in the same school classroom after the building was renovated in 2016. Surprisingly, the renovated classroom had a significantly higher concentration of CO2. It was found that this was due to the regulation of the heating system and the new airtight windows. The occupants of the renovated classroom have a maintained thermal comfort, but natural ventilation is rather neglected. A controlled ventilation strategy and installation of heat recovery units are recommended to solve these problems with the classroom’s indoor environment. Microbiological testing of the surfaces in school classrooms also shows the importance of fresh air and solar radiation access for indoor comfort.

scholarly journals Overview of Solutions for the Low-Temperature Operation of Domestic Hot-Water Systems with a Circulation Loop

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3350
Author(s):  
Theofanis Benakopoulos ◽  
William Vergo ◽  
Michele Tunzi ◽  
Robbe Salenbien ◽  
Svend Svendsen
Keyword(s):  
Low Temperature ◽  
Heat Loss ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Heating Power ◽  
Circulation Loop ◽  
Space Heating ◽  
District Heating System ◽  
Domestic Hot Water

The operation of typical domestic hot water (DHW) systems with a storage tank and circulation loop, according to the regulations for hygiene and comfort, results in a significant heat demand at high operating temperatures that leads to high return temperatures to the district heating system. This article presents the potential for the low-temperature operation of new DHW solutions based on energy balance calculations and some tests in real buildings. The main results are three recommended solutions depending on combinations of the following three criteria: district heating supply temperature, relative circulation heat loss due to the use of hot water, and the existence of a low-temperature space heating system. The first solution, based on a heating power limitation in DHW tanks, with a safety functionality, may secure the required DHW temperature at all times, resulting in the limited heating power of the tank, extended reheating periods, and a DH return temperature of below 30 °C. The second solution, based on the redirection of the return flow from the DHW system to the low-temperature space heating system, can cool the return temperature to the level of the space heating system return temperature below 35 °C. The third solution, based on the use of a micro-booster heat pump system, can deliver circulation heat loss and result in a low return temperature below 35 °C. These solutions can help in the transition to low-temperature district heating.

Evacuated Tube Heat Pipe Solar Collectors Applied to Recirculation Loop in a Federal Building: SSA Philadelphia

Solar Energy ◽  
2004 ◽  
Author(s):  
Andy Walker ◽  
Fariborz Mahjouri ◽  
Robert Stiteler
Keyword(s):  
Solar Energy ◽  
Heat Pipe ◽  
Heat Loss ◽  
Heating System ◽  
Hot Water ◽  
Solar Array ◽  
Solar Collectors ◽  
Water Heating ◽  
Evacuated Tube ◽  
Recirculation Loop

This paper describes design, simulation, construction and measured initial performance of a solar water heating system (360 Evacuated Heat-Pipe Collector tubes, 54 m2 gross area, 36 m2 net absorber area) installed at the top of the hot water recirculation loop in the Social Security Mid-Atlantic Center in Philadelphia. Water returning to the hot water storage tank is heated by the solar array when solar energy is available. This new approach, as opposed to the more conventional approach of preheating incoming water, is made possible by the thermal diode effect of heat pipes and low heat loss from evacuated tube solar collectors. The simplicity of this approach and its low installation costs makes the deployment of solar energy in existing commercial buildings more attractive, especially where the roof is far removed from the water heating system, which is often in the basement. Initial observed performance of the system is reported. Hourly simulation estimates annual energy delivery of 111 GJ/year of solar heat and that the annual efficiency (based on the 54 m2 gross area) of the solar collectors is 41%, and that of the entire system including parasitic pump power, heat loss due to freeze protection, and heat loss from connecting piping is 34%. Annual average collector efficiency based on a net aperture area of 36 m2 is 61.5% according to the hourly simulation.

scholarly journals Studies of factors affecting stability and efficiency of anion exchanger

2020 ◽  
Vol 177 ◽  
pp. 03020
Author(s):  
Nigora Mukhtarova ◽  
Bakhodir Aliev ◽  
Sadritdin Turabdzhanov ◽  
Latofat Rakhimova
Keyword(s):  
Ion Exchange ◽  
Anion Exchanger ◽  
Analytical Data ◽  
Polycondensation Reaction ◽  
Water And Wastewater Treatment ◽  
Factors Affecting ◽  
Exchange Processes ◽  
Physicochemical Factors ◽  
Swelling Capacity ◽  
Water And Wastewater

Various industries such as mining and the chemical industry are one of the most used ion exchange processes for water and wastewater treatment. The first section of this work presents the mechanism of the polycondensation reaction to obtain the polymer matrix of anion exchanger. Elemental analytical data conformed that anion exchanger holds 34,99% of nitrogen atoms and 44,47% oxygen atoms in the structure. In addition to the synthesis of the anion exchanger, physicochemical factors have a significant effect. The temperature of reactions for a certain time using a Lewis catalyst, the choice of the optimal solvent for improving swelling capacity of the starting monomers, due to their advantages as effective materials at a low price, are described in the second section. The information in the last section of the paper is devoted to the sorption properties and the ion-exchange processes in where the obtained anion exchanger was studied and used.

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