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Wyszukujesz frazę "heat efficiency" wg kryterium: Temat


Tytuł:
Pomiar mocy cieplnej pasywnego, powietrznego kolektora słonecznego
Measurement of thermal power of passive solar air collector
Autorzy:
Dutkowski, K
Piątkowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/151292.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
powietrzny kolektor słoneczny
badania eksperymentalne
moc cieplna kolektora pasywnego
solar air collector
experimental investigations
heat efficiency
Opis:
W artykule przedstawiono wyniki badań eksperymentalnych prototypowego, powietrznego kolektora słonecznego. Badania przeprowadzono w warunkach laboratoryjnych. Ich celem było wyznaczenie wpływu natężenia promieniowania na przyrost temperatury powietrza oraz prędkość przepływu powietrza (na skutek ruchów konwekcyjnych). W efekcie pomiarów wyznaczono natężenie przepływu powietrza oraz moc cieplną kolektora. Pionierskie rozwiązanie konstrukcyjne jak i wyniki badań będą stanowiły punkt odniesienia dla wyników badań innych konstrukcji.
The results of experimental investigations of the prototype flat air solar collector are presented in this paper. The collector consists of an aluminum casing with dimensions 1.04 m (width) x 2.08 m (height) x 0.18 m (thickness). The air inlet to the collector has an inlet channel with diameter, din, of 110 mm and a length of 0.5 m. The air outlet channel has an internal diameter, dout, 130 mm and a length of 0.5 m. The prototype solar air collector has a cover made of a cellular polycarbonate with a thickness of 5 mm and in brown color. The study was performed on a laboratory set-up. The collector worked under conditions of natural convection. The tests were performed for a range of irradiance I = 0 - 325 W/m2. The absorber surface temperature variations, air temperature increase and the collector thermal power were determined. It was found that at maximum irradiation, the air velocity was w = 1 m/s, volume flow rate of air = 28 m3/h, and the corresponding heat transfer rate was Q = 270 W.
Źródło:
Pomiary Automatyka Kontrola; 2014, R. 60, nr 10, 10; 868-871
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efektywność wymienników ciepła przy rekuperacji ciepła w wentylacji i klimatyzacji
The heat exchangers effectiveness in ventilation and air conditioning
Autorzy:
Grzebielec, A.
Rusowicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/271099.pdf
Data publikacji:
2012
Wydawca:
Centralny Ośrodek Badawczo-Rozwojowy Aparatury Badawczej i Dydaktycznej, COBRABiD
Tematy:
efektywność wymiennika ciepła
rekuperacja
wentylacja
klimatyzacja
heat exchanger efficiency
recuperation
ventilation
air conditioning
Opis:
W pracy przedstawiono możliwości odzysku ciepła w instalacjach wentylacyjnych i klimatyzacyjnych z wykorzystaniem rekuperacji. Omówiono efektywności energetyczne poszczególnych rozwiązań oraz zaprezentowano sposób określenia tej efektywności. Wykonano obliczenia dla dwóch typów wymienników ciepła: rura w rurze oraz wymiennika płytowego. Wyznaczono ich efektywności eksperymentalnie.
The paper presents the possibility of heat recovery in ventilation and air conditioning. There are discussed energy efficiency of individual solutions and demonstrates how to determine the effectiveness. The are shown calculations for two types of heat exchangers, duble-pipe type and plate. Their effectiveness was also determined experimentally.
Źródło:
Aparatura Badawcza i Dydaktyczna; 2012, 17, 2; 47-52
2392-1765
Pojawia się w:
Aparatura Badawcza i Dydaktyczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ograniczenia i efektywność wykorzystania sprężarkowych pomp ciepła w polskich ciepłowniach geotermalnych
Restrictions on use and effectiveness of compressor heat pumps in geothermal heating plants in Poland
Autorzy:
Pająk, L.
Hołojuch, G.
Powiązania:
https://bibliotekanauki.pl/articles/2062707.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
sprężarkowe pompy ciepła
efektywność pomp ciepła
ciepłownictwo
geotermia
compressor heat pump
heat pumps efficiency
district heating
geothermy
Opis:
W artykule zaprezentowano uwarunkowania techniczne i ekonomiczne, jakim muszą sprostać sprężarkowe pompy ciepła w polskich instalacjach grzewczych wykorzystujących wody geotermalne. W rozważaniach uwzględniono wymagane parametry pracy instalacji geotermalnych oraz strukturę zużycia nośników energii wykorzystywanych do produkcji energii elektrycznej napędzającej pompy ciepła. Mając na uwadze istniejące ograniczenia, określono warunki energetycznej i ekonomicznej opłacalności stosowania sprężarkowych pomp ciepła. Stwierdzono, że najmniej wymagającym kryterium opłacalności stosowania sprężarkowych pomp ciepła w polskich warunkach jest kryterium opłacalności energetycznej – aby było ono spełnione, przyjmując węgiel kamienny za paliwo odniesienia, konieczne jest uzyskanie średniorocznej wartości COP (współczynnik wydajności grzejnej pomp ciepła) powyżej 2,2, co jest w pełni osiągalne. Zdecydowanie ostrzejsze jest kryterium opłacalności ekonomicznej. Ustalono, że w odniesieniu do najpowszechniej stosowanych paliw konwencjonalnych średnioroczne wartości COP muszą zawierać się w przedziale: 5,0–7,7 dla węgla kamiennego; 3,3–5,6 dla sieciowego wysokometanowego gazu ziemnego; 1,7–2,0 dla lekkiego oleju opałowego i 1,0–1,4 dla sieciowej energii elektrycznej. Na tej podstawie stwierdzono, że osiągnięcie ekonomicznej opłacalności stosowania sprężarkowych pomp ciepła w odniesieniu do węgla kamiennego jest praktycznie nieosiągalne
The paper presents the technical and economic conditions that compressor heat pumps have to cope with in the Polish heating systems utilizing geothermal water. Required operating parameters of geothermal installations and the structure of energy consumption used for production of electricity driven heat pumps were taken into consideration. Given the existing restrictions, the terms of energy and economic viability of compressor heat pumps were determined. It was found that the least demanding criterion of effectiveness for compressor heat pumps utilization in Poland is the criterion of primary energy saving effectiveness (taking coal as the reference fuel it is necessary to obtain the annual average COP value above 2.2 – which is fully achievable). A definitely more stringent criterion is the economic viability. It was found that, for the most commonly used conventional fuels, the average COP value must be 5.0–7.7 for coal, 3.3–5.6 for network natural gas with a high methane content, 1.7–2.0 for light heating oil and 1.0–1.4 for network electricity. On this basis, the economic viability of compressor heat pumps for coal is practically unattainable.
Źródło:
Biuletyn Państwowego Instytutu Geologicznego; 2010, 439 (1); 155--158
0867-6143
Pojawia się w:
Biuletyn Państwowego Instytutu Geologicznego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimizing of Metal Foam Design for the Use as a Heat Exchanger
Autorzy:
Radkovský, F.
Gebauer, M.
Merta, V.
Powiązania:
https://bibliotekanauki.pl/articles/947585.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metal foam
3D modeling
heat exchanger
heat conduction
efficiency
Opis:
The work deals with possibilities of using this specific material. It is focused on cast metal foams with a regular arrangement of internal cells and it refers to already used casting technologies – the production of metal foams with the aid of sand cores. Metal foams are used in many industries, such as: automotive, aerospace, construction, power engineering. They have unique propertiesand due to lower weight with sufficient strength and greater contact surface can be used, for example, for the conduction of heat. This article deals with the use of the metal foam as a heat exchanger. The efficiency of the heat exchanger depends on its shape and size and therefore the study is focused first on the optimization of the shape before the proper manufacture.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 4; 1875-1881
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conceptual Design and Performance Analysis of an Exhaust Gas Waste Heat Recovery System for a 10000TEU Container Ship
Autorzy:
Ma, Zheshu
Yang, Dong
Guo, Qiang
Powiązania:
https://bibliotekanauki.pl/articles/259008.pdf
Data publikacji:
2012
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
exergy efficiency
marine diesel engine
thermal efficiency
waste heat recovery system
Opis:
According to operation characteristics of the main engine 9K98ME-C7, a combined turbines-exhaust gas waste heat recovery system is proposed to recover waste heat and increase system energy efficiency. Thermodynamic models based on the first thermodynamic law and the second thermodynamic law are formulated. The superheated steam yield, the total electric power yield, the first thermodynamic law efficiency, the exergy efficiency at different exhaust gas boiler working pressure, and the variation of the exergy efficiency under different feed water temperature and different steam turbine back pressure are analyzed. Thermodynamic results indicate that the most appropriate exhaust gas boiler pressure is 0.8MPa for studied main engine and the total thermal efficiency with combined turbines arrangement has climbed up to 53.8% from 48.5%.
Źródło:
Polish Maritime Research; 2012, 2; 31-38
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation of augmented thermal and performance characteristics of solar air heater ducts due to varied orientations of roughness geometry on the absorber plate
Autorzy:
Sahu, Mukesh Kumar
Matheswaran, M. M.
Bishnoi, Pardeep
Powiązania:
https://bibliotekanauki.pl/articles/239981.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solar air heater
SAH
thermal efficiency
heat removal factor
collector efficiency factor
artificial roughness
heat transfer rate
Opis:
This paper presents the outdoor experimental results for thermal performance analysis of artificially roughened solar air heaters (SAHs). Circular wire ribs have been arranged to form arc shape geometry on the absorber plates and have been tested for two configurations of SAHs named as arc shape apex-downstream flow and arc shape apex-upstream flow SAH. Roughness parameters have been taken as relative roughness pitch in the range of 8–15, angle of attack 45°–75°, and for fixed relative roughness height of 0.0454, duct width to duct height ratio of 11. During the experimental analysis the mass flow rate varied from 0.0100 to 0.0471 kg/s. Based on the experimental results it was found that roughness with apexupstream flow SAH is having higher value of thermal efficiency, heat removal factor and collector efficiency factor as compared to roughness with apexdownstream flow SAH and simple absorber plate SAH. In the range of the operating parameters investigated the maximum of thermal efficiency, heat removal factor, and collector efficiency factor have been found.
Źródło:
Archives of Thermodynamics; 2020, 41, 3; 147-182
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exergetic performance analysis of solar air heater with inverted L-shape ribs as roughness element
Autorzy:
Chaudhari, Manmohan
Sharma, Sohan Lal
Debbarma, Ajoy
Powiązania:
https://bibliotekanauki.pl/articles/27312231.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
solar air heater
heat transfer
exergy loss
exergy efficiency
thermal efficiency
Opis:
Improvement in the exegetic efficiency of a solar air heater (SAH) can be done by enhancing the rate of heat transfer. In this work, the exergetic efficiency optimization of an artificially roughened solar air heater having an inverted L-shape rib has been performed. The numerical analysis of the exergetic performance of the solar air heater was carried out at a constant heat flux of 1000 W/m2 . The study was conducted to investigate the effect of different relative roughness pitch (7.14–17.86) on the exergy losses, under the Reynolds number range of 3000 to 18 000. The roughness parameter of this geometry has been optimized and found to be among functional operating parameters like average solar intensity and temperature rise across the collector. The optimized value of relative roughness pitch is 17.86 at the isolation of 1000 W/m2 , and the parameter of temperature rise ranges from 0.005 to 0.04.
Źródło:
Archives of Thermodynamics; 2023, 44, 3; 241--267
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Series Arrangement of Economizer – Evaporator Flat Solar Collectors as an Enhancement for Solar Steam Generator
Autorzy:
Al-Saiydee, Mahmmod
Alhamadani, Ali
Allamy, Waleed
Powiązania:
https://bibliotekanauki.pl/articles/1838422.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
flat solar collector
solar radiation beam
heat gain
heat loss
operating efficiency
Opis:
Two flat solar collectors were designed and connected in series in order to achieve a moderately high outlet temperature. This high temperature is to be considered as the inlet temperature to a concentrated collector which is able of generating superheated steam. The first collector plays a role as a preheater; hence, it is called an economizer and the other plays a role as a temperature riser, thus it is called an evaporator. The economizer is a closed steel tank equipped with internal baffles distributed equally to ensure perfect circulation of water inside the tank. However, the evaporator consists of an array of vertical pipes connected to two horizontal manifolds (risers and headers) and bonded to a steel sheet. Both collectors are coated black with a granulated carbon layer and exposed to sun through two glass layers. Two water flow rates were applied at the evaporator 100 L/hr and 200 L/hr. The result shows that a maximum outlet temperature of 73°C and a maximum efficiency of 82% at the beginning of the experiment and 55% by the end of experiment were achieved when the flow rate was 100 L/hr. In addition, the result shows that both collectors reached a situation where there was no useful gain in heat even, though the solar radiation beam still hits with considerable high intensity. This situation occurs when the heat losses increase. Both heat gain and heat lost were calculated and plotted for both collectors and at the two flow rates. In addition, an average value of solar radiation beam during the experiment was plotted.
Źródło:
Journal of Ecological Engineering; 2021, 22, 5; 121-128
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solar concentrators in heat balance of the building
Solnechnye ustanovki s koncentratovom teplovom balance zdanija
Autorzy:
Denysova, T.
Powiązania:
https://bibliotekanauki.pl/articles/77978.pdf
Data publikacji:
2014
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
heat balance
electricity
heat energy
solar energy
solar collector
energy efficiency
building
Źródło:
Motrol. Motoryzacja i Energetyka Rolnictwa; 2014, 16, 5
1730-8658
Pojawia się w:
Motrol. Motoryzacja i Energetyka Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat and Cold Energy Storage Technologies as a Practical Complement to Renewable Energy Installations
Autorzy:
Mania, T.
Kawa, J.
Powiązania:
https://bibliotekanauki.pl/articles/1191856.pdf
Data publikacji:
2018
Wydawca:
Gdańska Szkoła Wyższa
Tematy:
energy storage
types of heat storage
heat storage loading and unloading
energy efficiency
heat pumps
Opis:
Thermal energy storage can be defined as temporary storage of heat energy at low or high temperatures. The development and innovative solutions of the thermal energy storage technology can, in the long-term, mitigate the negative impact on the environment and facilitate more energy-efficient exploitation of thermal energy systems. The main goal in thermal energy storage systems is to store the solar heat accumulated during the summer for heating in winter. The concept of such use of solar energy is not new, because it has already been developed and improved over the centuries, where it has played an important role in energy saving and significantly contributed to the improvement of energy efficiency and reduction of gas emissions to the atmosphere. The article presents the types of heat storages with particular emphasis on BTESstorage systems with examples of their applications.
Źródło:
Eco-Energetics: technologies, environment, law and economy; 2018, 1; 41--50
2657-5922
2657-7674
Pojawia się w:
Eco-Energetics: technologies, environment, law and economy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Opportunities of exhaust heat recovery and conversion to electricity
Autorzy:
Cienciała, M.
Kaźmierczak, A.
Krakowian, K.
Błasiński, T.
Powiązania:
https://bibliotekanauki.pl/articles/247492.pdf
Data publikacji:
2013
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
combustion engine
heat recovery
simulation
efficiency
environmental protection
Opis:
The maximum efficiency of the conventional spark ignition engine is 33%, in the case of diesel engines is 42%. The conclusion is that the energy contained in the fuel and "released" in the combustion process is converted into mechanical work only in a small degree. The rest of the energy is unfortunately lost by heat, friction, or used to drive the engine accessories. It should also be noted that these values are peak efficiency, which is achieved only when the engine works in optimal parameters. At most used parameters engines reach efficiency on the level of 10% to 25%. In modern cars with a hybrid powertrain are solutions that can improve the efficiency of conventional internal combustion engines. It is worth to notice that there are few ways to improve the efficiency of a reciprocating engine. The main technological trends on which research is underway are knock ignition and heat recovery from the exhaust. More development seems to be the second solution, because it can be used to design new engines such as the replacement of the alternator on the generator of electricity from exhaust heat. Besides, it will be possible to adapt these systems to in-use units, which improve the energy balance of riding vehicles. In article, you will find information of literature analysis for exhaust heat recovery and conversion to electricity solutions, computerized exhaust modification with flow calculations, real modification, test bench creation, researches and scores, analysis.
Źródło:
Journal of KONES; 2013, 20, 4; 63-70
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research to estimate energy efficiency of a ventilation and air conditioning heat pump system inside a production premise with ventilation air recovery
Autorzy:
Bezrodny, Myhailo Kostiantynovych
Misiura, Tymofii Oleksiyovych
Powiązania:
https://bibliotekanauki.pl/articles/1955060.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air conditioning
heat pump system
refrigeration efficiency
recuperation
Opis:
The research provides a thermodynamic analysis of the theoretical model of a ventilation and air conditioning heat pump system with the ventilation air cold energy recovery depending on outside air parameters, the recovery efficiency and characteristics of a premise. A confectionery production workshop was taken as a prototype where technological conditions (temperature and humidity) must be maintained during the warm season. Calculations using the method of successive approximations to estimate air parameters at system’s nodal points were conducted. It allowed to determine theoretical refrigeration efficiency of the studied system and proved advantages of heat recuperation for smaller energy consumption. The model can be applied for design of heating, ventilation, and air conditioning units which work as a heat pump. The studied system has the highest energy efficiency in the area of relatively low environment temperatures and relative humidity which is suitable for countries with temperate continental climates characterized by low relative humidity.
Źródło:
Archives of Thermodynamics; 2021, 42, 4; 69-86
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiz i modelirovanie teploobmennykh ustrojjstv v kontaktnykh apparatakh
Analysis and simulation of heat exchange devices in the contact devices
Autorzy:
Spinov, V.
Powiązania:
https://bibliotekanauki.pl/articles/77965.pdf
Data publikacji:
2014
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
heat exchange
contact
mass transfer
heat transfer
contact device
energy efficiency
mathematical model
Źródło:
Motrol. Motoryzacja i Energetyka Rolnictwa; 2014, 16, 5
1730-8658
Pojawia się w:
Motrol. Motoryzacja i Energetyka Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of the effects of changeable transverse and longitudinal pitches and porous media inserts on heat transfer from an elliptic tube bundle
Autorzy:
Razzaghi, H.
Layeghi, M.
Goodarzi, S.
Lotfizadeh, H.
Powiązania:
https://bibliotekanauki.pl/articles/281191.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
elliptic tube bundle
heat transfer
pitches
aluminum foam
efficiency
Opis:
In this paper, effects of changeable transverse and longitudinal pitches and porous media inserts on overall heat transfer from an elliptic tube bundle are studied numerically. Go- verning equations used for the analysis of fluid flow inside the porous media inserts are Darcy-Brinkman-Forchheimer equations, and for the fluid flow without porous inserts are classical Navier-Stokes equations. A finite volume code is used to solve the governing equ- ations. The tube bundle consists of 10 rows of elliptical tubes 3.17 cm in major diameter and 1.4 cm in minor diameter in a staggered arrangement. Aluminum foams are used as porous media inserts between the tubes with three different porosities. It is shown that the use of the aluminum foam enhances heat transfer significantly (more than 50% in some cases). However, the pressure drop increases as the Reynolds number grows. The differences among various cases are also discussed. Finally, it is shown that the overall heat transfer efficiency increases more effectively by increasing the transverse pitch with respect to the longitudinal and diagonal pitches while the flow regime remains laminar.
Źródło:
Journal of Theoretical and Applied Mechanics; 2014, 52, 3; 767-780
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected technical aspects of managing efficient heat supply in a district heating system
Autorzy:
Wrzalik, Aleksandra
Powiązania:
https://bibliotekanauki.pl/articles/29521087.pdf
Data publikacji:
2023
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
district heating
heat transmission
district heating main
flow velocity
heat losses
pressure losses
efficiency
Opis:
District heating networks are key components of efficient heat supply systems for municipal and industrial consumers. The purpose of the research presented in this article was to analyze the thermo-hydraulic parameters of the operation of a transmission main in a district heating network to improve the heat transfer efficiency. Based on a literature review of existing studies, the basic issues of the heat supply process were discussed, and selected methods and tools for simulating district heating networks were characterized. A detailed mathematical description of the phenomena occurring during heat transport in a district heating network pipeline was also presented. Then, analytical calculations and simulations were carried out for the selected district heating system using Termis software. Operational parameters collected in the actual district heating system were used as output data for analytical modeling. Pressure drops, power losses, and heat transfer efficiencies in the main buses at different outdoor temperatures during the heating season were determined. Selected results of the study were included, and possibilities for improving the efficiency of heat transfer in the studied district heating network were indicated.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2023, 76 (148); 32-41
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł

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