Thesis (PhD)--Stellenbosch University, 1997 / ENGLISH ABSTRACT: An experimental investigation on gas-liquid counterflow in inclined rectangular ducts is conducted. The pressure drop across the sharp-edged gas inlet and the pressure gradient inside the duct are measured. Combinations of water, methanol, propanol, air, argon, helium and hydrogen are tested. The duct height and width are varied from 50 mm to 150 mm and 10 mm to 20 mm respectively. The emphasis is on high void fraction flow, i.e. low liquid flow rates as encountered in air-cooled reflux condensers. At low to moderate gas flow rates the pressure gradient is gas Reynolds number related while it becomes dependent on the superficial densimetric gas Froude number as the gas flow is increased. According to experiment the hydraulic diameter is the required length dimension in the gas Reynolds number while the duct height becomes the characteristic dimension in the Froude number regime. Flooding curves are generated for duct inclinations from close to the horizontal to the vertical. The data correlate in terms of the phase Froude numbers and a dimensionless liquid property parameter containing the hydraulic diameter, density, surface tension and the viscosity. The flooding gas velocity is found to be strongly dependent on the duct height, the phase densities and the duct inclination. The liquid viscosity has a stronger effect than the surface tension. Both these properties however playa secondary role. Flooding is not related to the gas Reynolds number. A theoretical model, based on the phenomenological findings of the adiabatic counterflow investigation, is derived to evaluate the performance of an air-cooled reflux condenser. Field tests are conducted on a full scale reflux condenser and the measured performance is compared to the model prediction. The reflux condenser is found to achieve only 60% of the predicted heat rejection rate due to the existence of so-called cold or dead zones. Indications are that excessive entraiment in the bottom header and the subsequent accumulation of condensate in the finned tubes causes a maldistribution of the steamside flow. In the process noncondensable gases accumulate and form dead zones, causing ineffective performance. Flooding as found in single-ducts does not appear to contribute to the formation of the dead zones. / AFRIKAANSE OPSOMMING: Die teenvloei van gas en vloeistof in reghoekige skuins buise is eksperimenteel ondersoek. Die drukverlies oor die skerp gasinlaat en die drukval in die buis is gemeet vir verskillende kombinasies van water, propanol, metanol, lug, argon, helium en waterstof. Buishoogtes en breedtes van 50 mm tot 150 mm en 10 mm tot 20 mm respektiewelik is getoets. Die klem van die ondersoek is op lae vloeistofvloeitempos soos teenwoordig tydens kondensasie van stoom in lugverkoelde teenvloeikondensors. Vir lae tot matige gasvloeitempos is die drukval afhanklik van die gas Reynolds-getal terwyl die densimetriese gas Froude-getal die heersende parameter word soos die gasvloei toeneem. Die hidrouliese diameter verteenwoordig die dimensie in die Reynolds-getal maar die buishoogte word die karakteristieke dirnensie in die Froude-getal gebied. Vloedingskurwes is vir 'n reeks van buishoeke gegenereer. Die vloedingdata korreleer in terme van die Froude-getal en 'n dimensielose parameter bestaande uit die hidrouliese diameter, oppervlakspanning, vloeistofdigtheid en die vloeistofviskositeit. Die vloeidingsnelheid is primêr van die buishoogte, vloeierdigthede en die buishoek afhanklik. Die vloeistofviskositeit-effek is sterker as die van die oppervlakspanning. Beide die eienskappe speel egter 'n sêkondere rol. Die gas Reynolds-getal beïnvloed nie die vloeidingsproses nie. Die fundamentele bevindinge van die teenvloeiondersoek is toegepas om die werkverigting van 'n lugverkoelde teenvloeikondenser teoreties te modelleer. Werkverigtingstoetse is uitgevoer op 'n volskaal teenvloeikondenser. Die toetsresultate word vergelyk met die teoretiese voorspelling. Die teenvloeikondensor behaal slegs sowat 600% van die voorspelde warmteoordrag omdat van die gevinde buise gedeeltelik by omgewingstemperatuur is. Hierdie verskynsel heet koue of dooie sones. Dit blyk dat die kondensaat in die onderste spruitstuk nie vrylik kan dreineer nie en in die vorm van druppels deur die stoom opgesleur word. Gevolglik versamel kondensaat binne die buise en sodoende kan nie-kondenseerbare gasse nie effektief uit die teenvloeikondensor verwyder word nie. Soos die gasse versamel word koue sones gevorm. Dit blyk dat vloeding soos waargeneem in enkelbuise nie tot die vorming van koue sones bydra nie.

Transport Membrane Condenser (TMC) is an innovative technology based on the property of a nano-scale porous material which can extract both waste heat and water from exhaust gases. This technology tremendously improves the efficiency of boilers and gas/coal combustors by lowering waste heat and increasing water recovery. Contaminants in the flue gases, such as CO2, O2, NOx, and SO2 are inhibited from passing through the membrane by the membrane’s high selectivity. The condensed water through these tubes is highly pure and can be used as the makeup water for many industrial applications. The goal of this research is to investigate the heat transfer, condensation rate, pressure drop and overall performance of crossflow heat exchangers. In this research, a numerical model has been developed to predict condensation of water vapor over and inside of nano-porous layers. Both capillary condensation inside the nanoscale porous structure of the TMC and the surface condensation were considered in the proposed method using a semi-empirical model. The transport of the water vapor and the latent heat of condensation were applied in the numerical model using the pertinent mass, momentum, turbulence and energy equations. By using the proposed model and simulation procedure, the effect of various inlet parameters such as inlet mass flow rate, inlet temperature, and water vapor content of the inlet flow on the performance of the cross-flow TMC heat exchanger was studied to obtain the optimum performance of the heat exchangers at different working conditions. The performance of the TMC heat exchangers for inlet flue gas rate 40 to 120 kg/h, inlet water rate 60 to 140 kg/h, inlet flue gas relative humidity 20 to 90%, and tube pitch ratio 0.25 to 2.25 has been studied. The obtained results show that the water condensation flux continuously increases with the increase of the inlet flue-gas flow rate, water flow rate, and the flue-gas humidity. The total heat flux also follows the same trend due to the pronounced effect of the latent heat transfer from the condensation process. The water condensation flux and the overall heat transfer increase at the beginning for small values of the tube pitches and then decreases as the tube pitch increases furthermore. In addition to the cross-flow TMC heat exchangers, the performance of a shell and tube TMC heat exchanger for high pressure and temperature oxy-combustion applications has been investigated. The performance analysis for a 6-heat exchanger TMC unit shows that heat transfer of the 2-stage TMC unit is higher than the 2-stage with the same number of the heat exchanger in each unit.

A batch vacuum frying system, which processes fruits and vegetables, includes a frying pan, a surface-condenser, and a vacuum pump. With health and safety issues in mind, this research focused on developing a modified surface-condenser to prevent cavitation of the vacuum pump. The final oil-content was reduced by centrifugal de- oiling of the product under vacuum, which make the product healthier than what is currently available. The de-oiling mechanism consists of a centrifuge with a motor attached to the basket shaft, rotating up to 750 rpm (63 g units). The condenser consists of a (counter- flow) spiral-coil heat exchanger (SHE) connected to a refrigeration system that uses R404a refrigerant. De-oiling for 40 s at 300 and 750 RPM removed up to 67% and 72% of the chip’s surface oil, respectively. At 750 RPM for 10 s, 40 s, and 60 s the oil-content was reduced by 38%, 44%, and 51%, respectively. The convective heat transfer coefficient (h) of the frying oil was determined at 120°C and 140°C using the lumped capacitance method. The h-values were 217±13 W/m2K (120°C) and 258±37 W/m2K (140°C) using a copper-ball thermocouple. The h- values increased to 3.6 times during the boiling period. COMSOLTM Multiphysics was used to model the heat transfer in the vacuum fryer pan. Based on the simulation results, a 1.5 cm thick insulation material was installed in the fryer to reduce the energy losses. The refrigeration system operates at Tevap = -26°C and Tcond = 50°C with 26°C sub-cooling. Sensitivity analysis showed that the system Coefficient of Performance (COP) was about 3.87 at these conditions and compressor power requirement (CPR) was 74 W (85% efficiency) when frying 30 g of potatoes slices. The best results were obtained at Tevap = -10°C and Tcond = 40°C with 26°C sub-cooling and superheat of 5°C. The predicted COP was 4 and the CPR 70 W. The ice-formation on coils reduced the condensation rate. Reducing the refrigerant temperature to -10°C (from -26°C) reduced the condensation rate by 30%. These results show a more effective vacuum frying system for high-quality fruits and vegetables than the system previously used.

It is inevitable to observe that, in an urban field any architectural enterprise is subject to changing political, financial, technological and cultural demands. The pressure of these ever-changing forces attempts to modify and replace the initial program and the activities associated with the architectural product. The lifespan and the success of the resulting edifice depend on its ability to respond to such changes. Nevertheless, these ever-changing forces are naturally ambiguous and unpredictable so that architectural program becomes indeterminate. This thesis claims that in order to deal with the programmatic indeterminacy in an urban context, a strategic approach should be employed throughout the design process. Therefore, the thesis critically analyzes the strategic way of design to understand its working principles via examining the Parc de la Villette competition project of Rem Koolhaas/OMA. The mechanism of strategic way of design, how it works, and how it is constructed are the main focus of the thesis.

Three experimental studies were conducted to quantify the effects of system cycling, evaporator airflow, and condenser coil fouling on the performance of residential air conditioners. For all studies, the indoor dry-bulb (db) temperature was 80°F (26.7°C) db. The cycling study consisted of twelve transient tests conducted with an outdoor temperature of 95°F (35°C) db for cycle times of 6, 10, 15, and 24 minutes. Indoor relative humidities of 40%, 50%, and 60% were also considered. The evaporator airflow study consisted of twenty-four steady-state tests conducted with an indoor condition of 67°F (19.4°C) wet-bulb (wb) for evaporator airflows ranging from 50% below to 37.5% above rated airflow. Outdoor temperatures of 85°F (29.4°C) db, 95°F (35°C) db, and 105°F (40.6°C) db were also considered. The coil fouling study used a total of six condensers that were exposed to an outdoor environment for predetermined amounts of time and tested periodically. Three of the condensers were cleaned and retested during the periodic testing cycles. Testing consisted of thirty-three steady-state tests conducted with an indoor condition of 67°F (19.4°C) wb for outdoor exposure times of 0, 2000, 4000, and 8000 hours. Outdoor temperatures of 82°F (27.8°C) db and 95°F (35°C) db were also considered.

Orientador: Vivaldo Silveira Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-15T20:10:11Z (GMT). No. of bitstreams: 1 ChavezGutierrez_MirkoSalomon_M.pdf: 5850684 bytes, checksum: 9125e38d9fe164c0e08b0242569f71af (MD5) Previous issue date: 2010 / Resumo: Os equipamentos utilizados para refrigeração e condicionamento ambiental têm um potencial significativo de redução de consumo energético, principalmente porque esta pratica utilizam quantidades significativas de energia e são encontrados em todas as residências e indústrias. Neste contexto existem numerosos estudos dirigidos para aumentar a eficiência energética dos sistemas de refrigeração domésticos, utilizando diferentes estratégias tecnológicas. O dispositivo proposto neste trabalho atua como um condensador evaporativo, substituindo o ar,, como meio de troca térmica convencional dos sistemas de refrigeração domésticos, por uma corrente vertical de água em contato com a superfície do condensador, aproveitando desta maneira o calor absorvido pela água na mudança de fase (efeito evaporativo) e diminuindo a temperatura de condensação. O protótipo foi desenvolvido, considerando o principio de funcionamento dos condensadores evaporativos industriais e adaptado numa escala menor, para que possa ser facilmente montado na estrutura de um refrigerador doméstico convencional. Com as mudanças nas condições de condensação, especificamente a temperatura, procura-se aumentar o COP (coeficiente de desempenho) que é um indicador da eficiência do sistema, dado que nessas condições de funcionamento, o efeito frigorífico torna-se maior e o trabalho do compressor torna-se menor durante o ciclo. Estas condições de funcionamento, assim como o consumo de energia elétrica, foram monitorados e comparados com os sistemas de refrigeração convencional, utilizando uma câmara especialmente condicionada para esse propósito. Assim, o desempenho do sistema com as novas condições de condensação, promovidas pelo dispositivo, teve uma maior eficiência global com um COP maior em 24% e, em consequência, um aumento da eficiência energética do sistema, com uma redução de 17% de energia em ensaios padronizados conforme norma ABNT 12888 / Abstract: Los equipos utilizados para refrigeración y condicionamiento ambiental tienen gran potencial de reducción de consumo energético, principalmente porque estos aparatos utilizan cantidades significativas de energía y son encontrados en la mayoría de residencias y en las industrias. Existen numerosos estudios dedicados a aumentar la eficiencia energética de los sistemas de refrigeración domésticos utilizando diferentes estrategias tecnológicas. El dispositivo propuesto en este trabajo actuara como un condensador evaporativo, substituyendo el aire, como medio de intercambio de calor convencional de los sistemas de refrigeración domésticos, por una corriente vertical de agua en contacto con la superficie del condensador, aprovechando de esta forma el calor absorbido por el agua durante el cambio de estado (efecto evaporativo) y disminuyendo la temperatura de condensación. Este prototipo fue desarrollado considerando el principio de funcionamiento de los condensadores evaporativos industriales y fue adaptado a una escala menor, para que pueda ser fácilmente instalado en la estructura de un refrigerador domestico convencional. Con las modificaciones en las condiciones de condensación específicamente, la temperatura, se procura aumentar el COP (coeficiente de desempeño), que es un indicador de la eficiencia del sistema, en vista que en estas condiciones de funcionamiento, el efecto frigorífico se torna mayor y el compresor trabaja menos durante el ciclo. Estas condiciones de funcionamiento, así como el consumo de energía eléctrica son monitoreados e comparados con los sistemas de refrigeración convencional, utilizando una cámara especialmente condicionada para este propósito. De esta manera el desempeño del sistema con las nuevas condiciones de condensación, promovidas por el dispositivo en estudio, tuvo una mayor eficiencia global con un COP superior en 24%, y como consecuencia un aumento de la eficiencia energética del sistema, con una reducción del consumo de energía en 17% durante ensayos homogenizados según la norma Brasileña ABNT 12888 / Mestrado / Mestre em Engenharia de Alimentos

This PhD work has been dedicated to the improvement of the modelling of air condensers of both round tube and fins (RTPFs) and Minichannel technologies. The calculation platform employed is IMST-ART. This is a dedicated software for the design of refrigeration, air-conditioning and heat pump equipment following the vapor compression cycle. The model implemented in IMST-ART for condensers and evaporators is the combination of a segment-by-segment approach with the numerical method SEWTLE (Semi Explicit method for Wall Temperature Linked Equations) for the solution of the resulting system of equations. The target of the first part of this thesis was the comparative analysis of the empirical correlations aimed at the evaluation of the heat transfer coefficients and pressure drop in both the air and refrigerant sides of a condenser. The Literature review pointed out the presence of many studies concerning the condensation modelling. Therefore, after selecting the most interesting to compare, the first objective of this first part of the PhD became the identification of a suitable methodology for defining the best combination of correlations for the estimation of the thermo-hydraulic performance of the condensers. After an in-depth analysis of different possibilities, a well-defined methodology was identified as the best for the purpose. In the thesis, it was successfully applied to the identification of the best set of correlations for the heat transfer coefficients and friction factors for both the round-tube and minichannel condensers. The second part of the PhD was targeted to the improvement of the condensation modelling. In particular, the attention was focused on the analysis of the phenomena taking place at the beginning of the condensation process, when the superheated vapor finds the wall of the condenser being at a temperature lower than the refrigerant saturation temperature, i.e. convective condensation superheated vapor zone (CSH zone). It is well known that, in this zone, the condensation starts with some kind of droplet/thin film condensation on the walls. Afterwards, the bulk of the refrigerant flow reaches the saturation temperature and the condensation occurs at saturated conditions. Hence, the PhD thesis has been dedicated to the implementation in the general model for condensers (in IMST-ART software) of this CSH zone, which it was found to have an important effect on the prediction of the wall temperatures distribution in the tested air condensers. Two different numerical solutions were implemented and compared, i.e. Temperature and Enthalpy approaches, and validated against experimental results. Prediction results are very similar, thus the Enthalpy approach was selected because it required lower computational time. The final part of thesis was oriented towards the study of the effect of airflow maldistribution on the performance of air condensers. An innovative experimental methodology for generating and measuring any uneven air velocity profile at the inlet of a heat exchanger was first developed in a dedicated wind tunnel and then applied for the analysis of the performance degradation of one sample of condenser of each RTPFs and Minichannel technologies. Three different velocity profiles were produced and tested along a wide set of operating conditions, including different refrigerant charges and hence subcoolings. The experimental results showed that, although differences in wall temperature distribution were significant, the effect of air maldistribution on the performance of the two tested condensers was small. The improved model was validated against the experimental results and also showed little effect on condenser performance. Finally, the agreement between the results of the simulation and the experimental results was very satisfactory. / Este trabajo de doctorado se ha dedicado a la mejora del modelado de condensadores de aire, con tecnología de tubos y aletas o minicanales. La plataforma de software empleada es IMST-ART, que es un software dedicado a asistir el diseño de equipos de refrigeración, aire acondicionado y bomba de calor, basados en el ciclo de compresión de vapor. El modelo de IMST-ART para condensadores y evaporadores se basa en una aproximación segmento a segmento combinada con el método numérico SEWTLE (Semi Explicit method for Wall Temperature Linked Equations) para la solución del sistema de ecuaciones resultante. El objetivo de la primera parte de esta tesis fue el análisis comparativo de las correlaciones empíricas destinadas a evaluar los coeficientes de transferencia de calor y la caída de presión para condensadores de aire, tanto para el lado del aire como para el del refrigerante. La revisión de la Literatura mostró la existencia de numerosos estudios sobre el modelado de la condensación en este tipo de intercambiadores. Por lo tanto, después de la selección de las correlaciones más interesantes a comparar, el primer objetivo de esta primera parte de la tesis resultó el encontrar la metodología más adecuada para la identificación de cuáles eran las correlaciones que mejor estimaban el comportamiento termo-hidráulico de los condensadores. Después de un análisis en profundidad de diferentes posibilidades, se encontró la metodología claramente más adecuada y se pasó a aplicarla a la identificación del mejor conjunto de correlaciones para los coeficientes de transferencia de calor y factores de fricción para condensadores de aire. La segunda parte del doctorado se dirigió a la mejora del modelado del comienzo del proceso de condensación cuando el vapor sobrecalentado encuentra la pared del condensador a una temperatura que está por debajo de la temperatura de saturación del refrigerante en lo que se puede denominar como condensación convectiva en la zona de vapor sobrecalentado (zona CSH). Es bien sabido que la condensación comienza en esta zona con algún tipo de condensación de gotas/película delgada sobre las paredes antes de que el núcleo del flujo de refrigerante alcance la temperatura de saturación y la condensación se produzca en condiciones saturadas. La segunda parte del doctorado se ha dedicado a la implementación en el modelo general de condensadores (en el software IMST-ART) de esta zona CSH, que se encontró que tenía un efecto importante en la predicción de la distribución de las temperaturas de la pared en los condensadores de aire ensayados. Se implementaron y compararon dos soluciones numéricas diferentes, denominados aproximación de temperatura y aproximación de entalpía respectivamente, y se validaron por comparación con resultados experimentales. La predicción resultó ser muy similar con ambas aproximaciones por lo que finalmente se seleccionó la aproximación de entalpía por ser considerablemente más rápida. La parte final de la tesis se orientó hacia el estudio del efecto de la mala distribución del flujo de aire en el rendimiento de los condensadores de aire. Para este fin se desarrolló una metodología experimental innovadora capaz de generar y medir cualquier perfil de velocidad de aire no uniforme a la entrada de un intercambiador de calor. El desarrollo se llevó a cabo primero en un túnel de viento específicamente dedicado a este propósito y luego se aplicó para el análisis de la degradación de las prestaciones de dos muestras de condensador de cada una de las tecnologías estudiades: RTPFs y Minicanal. Mediante la metodología desarrollado se generaron tres perfiles de velocidad diferentes que se ensayaron a lo largo de un amplio conjunto de condiciones de funcionamiento, incluyendo diferentes cargas de refrigerante y, por tanto, grados de subenfriamiento en el refrigerante. Los resultados experimentales mostraron que el efecto de la mala distrib / Aquest treball de doctorat s'ha dedicat a la millora de la modelització de condensadors d'aire, amb tecnologia de tubs i aletes o minicanals. La plataforma de software emprada és IMST-ART, que és un software dedicat a assistir el disseny d'equips de refrigeració, aire condicionat i bomba de calor, basats en el cicle de compressió de vapor. El model de IMST-ART per condensadors i evaporadors es basa en una aproximació segment a segment combinada amb el mètode numèric SEWTLE (Semi Explicit method for Wall Temperature Linked Equations) per a la solució del sistema d'equacions resultant. L'objectiu de la primera part d'aquesta tesi va ser l'anàlisi comparativa de les correlacions empíriques destinades a avaluar els coeficients de transferència de calor i la caiguda de pressió per condensadors d'aire, tant per al costat de l'aire com per al del refrigerant. La revisió de la Literatura va mostrar l'existència de nombrosos estudis sobre la modelització de la condensació en aquest tipus d'intercanviadors. Per tant, després de la selecció de les correlacions més interessants a comparar, el primer objectiu d'aquesta primera part de la tesi va resultar el trobar la metodologia més adequada per a la identificació de quines eren les correlacions que millor estimaven el comportament termo-hidràulic dels condensadors. Després d'una anàlisi en profunditat de diferents possibilitats, es va trobar la metodologia clarament més adequada i es va passar a aplicar-la a la identificació del millor conjunt de correlacions per als coeficients de transferència de calor i factors de fricció per condensadors d'aire. La segona part del doctorat es va dirigir a la millora de la modelització del començament del procés de condensació quan el vapor sobreescalfat troba la paret del condensador a una temperatura que està per sota de la temperatura de saturació del refrigerant, en el que es pot denominar com condensació convectiva a la zona de vapor sobreescalfat (zona CSH). És ben sabut que la condensació comença en aquesta zona amb algun tipus de condensació de gotes/pel·lícula sobre les parets abans que el nucli del flux de refrigerant arribi a la temperatura de saturació i la condensació es produeixi en condicions saturades. La segona part del doctorat s'ha dedicat a la implementació en el model general de condensadors (en el programari IMST-ART) d'aquesta zona CSH, que es va trobar que tenia un efecte important en la predicció de la distribució de les temperatures de la paret en els condensadors d'aire assajats. Es van implementar i van comparar dues solucions numèriques diferents, denominades aproximació de temperatura i aproximació d'entalpia respectivament, i es van validar per comparació amb resultats experimentals. La predicció va resultar ser molt semblant amb les dues aproximacions pel que finalment es va seleccionar l'aproximació d'entalpia per ser considerablement més ràpida. La part final de la tesi es va orientar cap a l'estudi de l'efecte de la mala distribució del flux d'aire en el rendiment dels condensadors d'aire. Amb aquesta finalitat es va desenvolupar una metodologia experimental innovadora capaç de generar i mesurar qualsevol perfil de velocitat d'aire no uniforme a l'entrada d'un intercanviador de calor. El desenvolupament es va dur a terme primer en un túnel de vent específicament dedicat a aquest propòsit i després es va aplicar per a l'anàlisi de la degradació de les prestacions de dues mostres de condensador de cadascuna de les tecnologies estudiades: RTPFs i Minicanal. Mitjançant la metodologia desenvolupada es van generar tres perfils de velocitat diferents que es van assajar al llarg d'un ampli conjunt de condicions de funcionament, incloent càrregues diferents de refrigerant i, per tant, graus de subrefredament en el refrigerant. Els resultats experimentals van mostrar que l'efecte de la mala distribució de l'aire en les prestacions dels dos condensadors provats va / Pisano, A. (2017). Analysis of the condensation process and air maldistribution in finned tube and minichannel condensers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86182 / TESIS

This master‘s thesis deals with the design of a control system for a distillation column. It deals with the issue of distillate production and acquaints the reader with the necessary knowledge that is necessary to understand the purpose of the work. The practical part of the work presents a specific distillation column, the means for its control and the method of implementation of the control system, then the visualization of the control system and the method of control. Part of the work is the evaluation of the results and benefits of the work.

The thesis is focused on the cooling cycles, namely cycles of absorption. The work is divided into several parts, as problems to be solved. The first part deals with the principles and using refrigeration cycles in practice, their involvement and by comparing the working pairs of substances circulating in the absorption unit. The practical part deals with making a proposal for one-and two-level modular absorption cycle of 6 kW, and the subsequent techno-economic comparison with commonly supplied absorption unit

This thesis deals with the calculation procedures for determining the heat transfer coefficient for steam condensers. The first section provides a basic overview for industrial steam condensers and possible procedure for selecting the appropriate type of tube condenser. The next section describes the types of condensation and equations for determining the heat transfer coefficient for various geometries of tubular condensers. In the final section there is performed practical calculation of condenser in Maple software using the above relations. The results obtained in this calculation are compared with the results obtained by professional computational software Chemcad and HTRI.