O setor residencial reflete a cultura do uso excessivo da eletricidade para aquecimento de água. Para este uso final, a inclusão de gás e complementação com energia termo-solar pode apresentar vantagem por se tratar de energia final mais compatível com os processos de transformação em energia útil na forma de calor. A inclusão destas fontes pode propiciar uma diminuição de sobrecarga no sistema elétrico e da eletrotermia no setor residencial. Este trabalho faz uma avaliação econômica dos sistemas de aquecimento de água elétrico, a gás e solar. Os sistemas são analisados considerando custos de infra-estrutura, com diferentes disponibilidades de uso, custos de equipamentos e de operação para vários níveis de consumo. A avaliação é aplicada a 3 tipologias de edificações verticais representativas no mercado da construção civil da Região Metropolitana de São Paulo. Os custos de serviço de aquecimento de água quente estão apresentados em função do volume de água consumido. / The residential sector reflects the culture of the indiscriminate use of electricity water heating. Inclusion of gas and thermosolar energy to the electrical supply system may present advantages as they are more compatible to consumer\"s heat transformation processes. In addition these new sources of energy may decrease the electrical and electrothermal system overload in the residential sector. This study is an economic evaluation of the electric, gas and solar water heating systems. The heating systems are analyzed taking in consideration infrastructure costs, and equipment and operation costs for different levels of consumption. The evaluation is applied to three typologies of vertical residential edifications that represent the civil construction market of the São Paulo metropolitan area. The costs of water heating service are presented in function of the consumed volume of water.

O presente trabalho consiste em um estudo experimental sobre o efeito do controle de vazões em sistemas de aquecimento solar de água em instalações com grande número de coletores, onde o gradiente de temperatura não é suficiente para circular a água por termossifonagem. Foi avaliado o desempenho de todo o sistema sob diferentes condições de insolação, de vazão, de diferenciais de temperatura entre os coletores e o reservatório, em regime não permanente. Os resultados experimentais foram comparados com a equação de rendimento dos coletores, para condições de regime quase permanente, obtida segundo a norma da ABNT - NBR 10184/1988. Os ensaios foram realizados em duas baterias de testes, cada uma composta de dois coletores industrializados e um reservatório isolado termicamente. Em uma destas baterias, o fluxo de água entre os coletores e o reservatório ocorreu por termossifonagem, isto é, sem nenhuma restrição à vazão; na outra bateria, a vazão foi controlada por um registro e uma bomba hidráulica. Um sistema de automação coletou e processou os dados de forma a permitir a execução dos controles desejados, inclusive a simulação de consumo de água quente. O sistema com circulação natural, isto é, por termossifão, demonstrou ter uma grande habilidade de se adaptar à disponibilidade de energia com as temperaturas da água armazenada, por meio da otimização da velocidade da troca de calor. Foi desenvolvido, tomado como referência o escoamento por termossifão, um modelo de operação para sistemas diretos ativos que calcula a vazão com base no monitoramento das temperaturas das extremidades das tubulações que interligam o reservatório e os coletores, temperatura do ar, radiação solar disponível e vazão no instante anterior. O modelo foi testado experimentalmente e a operação do sistema ativo resultou em significativa melhora a eficiência. / The focus of this work is the experimental study of the effect of water control discharge in solar water-heating systems with a large number of collectors where the temperature gradient is not sufficient for thermosiphon water circulation. The performance of the system was evaluated under different conditions of solar radiation, flow rate, temperature differential between solar collectors and the storage tank and under transient conditions. The results were compared to a collector\'s performance equation of the quasi-steady-state model according to ABNT-NBR 10184/1988 standard. The tests were carried out on two systems each one constituted of two manufacturing collectors and one thermal tank. In one of these systems the flow between the collectors and storage occurred by thermosiphoning, i.e., by natural convection and without discharge restrictions. In the other, the flow control was done by means of a valve and a pump. In order to allow the execution of the desired controls, including hot water consumption, data were colleted and controlled through an automation system. The system of natural circulation shows a great ability to adaptation of disposal energy with water temperature stored, through velocity of heat exchange optimization. An operation model was developed, having thermosiphoning water circulation as reference, for active direct circulation systems that calculate the discharge taking into consideration the monitoring of the differential temperature between solar collectors and the storage tank, the air temperature, solar radiation available and the flow rate on previous time interval. This model was experimentally tested and resulted in a significant improvement in performance of the system operation.

Made available in DSpace on 2017-07-10T15:14:23Z (GMT). No. of bitstreams: 1 DissertacaoMarcosVSchlichting.pdf: 1630212 bytes, checksum: ac35da2426e86a1f7ad159d82eaf4416 (MD5) Previous issue date: 2015-03-12 / This study evaluated a prototype for heating water for use in the agricultural industry, based on the principle of magnetic induction to generate thermal energy through the eddy currents associated with a mechanical energy source for variation of magnetic flux produced by permanent magnets, configured with four six magnets with and without pole reversal, as compared with the water heating done through a resistive system. Induced systems obtained yield 64.74%, 65.13% and 64.48% for six magnets without inversion (6ISI), four magnets with reverse (4ICI) and four magnets without inversion (4ISI) respectively. The resistive system showed 89.21% efficiency, demonstrating greater viability in the study conditions. / O presente trabalho avaliou um protótipo para aquecimento de água para uso na agroindústria, baseado no princípio da indução magnética para geração de energia térmica através das correntes de Foucault associado a uma fonte de energia mecânica para variação do fluxo magnético produzido por imãs permanentes, configurado com quatro e seis imãs com e sem inversão de polos, em comparação com o aquecimento de água feito através de um sistema resistivo. Os sistemas induzidos obtiveram rendimento de 64,74 %, 65,13 % e 64,48 % para seis imãs sem inversão (6ISI), quatro imãs com inversão (4ICI) e quatro imãs sem inversão (4ISI) respectivamente. O sistemas resistivo apresentou eficiência de 89,21%, demonstrando maior viabilidade nas condições do estudo

Due to rising energy costs and increasing environmental awareness, various methods of energy conservation are being investigated. In the residential sector, both solar and heat pump systems have been extensively tested. Recently, combinations of solar and heat pump systems have been developed for both space heating and water heating. These systems have the capability to provide better performances than either of the systems operating on their own. The solar collector benefits from a lower fluid (glycol) inlet temperature which increases efficiencies, and the heat pump benefits from higher evaporator temperatures due to the additional solar energy collected. For this study, a prototype of an Indirect-Solar Assisted Heat Pump for use in the Canadian environment was constructed, instrumented and tested. Controlled, constant temperature tests, as well as solar profile tests were conducted and the heat transfer rates, natural convection flow rate, and heat pump coefficient of performance (COP) were calculated. These values were then compared to simulation results based on a model developed in a previous feasibility study. The experimental COPs calculated ranged from 2.3 to 3.3 throughout the full range of tests which were conducted with supply temperatures ranging from 0°C – 40°C. The simulated results consistently overestimated the experimental results by between 12% - 15%. New empirical heat exchanger relationships were developed for the model bringing the simulated results within 5% of the experimental results for tests run at glycol flow rates of 77 and 154 kg/hr. These relationships were used to refine the model, and produce updated annual performance values in the TRNSYS simulation software. Updated results showed a 5% drop in the annual free energy ratio in Toronto from 57% to 52%, but further optimization of the system using the TRNSYS software package improved annual results up to 56%. For the purposes of the study, a solar assisted heat pump prototype was constructed and tested successfully within the laboratory environment. Results showed that the system has a strong market potential, especially in regions without a strong solar resource. Based on these results further research is recommended, continuing with a full year outdoor test using unglazed solar collectors. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2010-10-12 18:53:01.189

Thesis (M.S.M.E)--Baylor University, 2009. / Includes bibliographical references (p. 133-134).

Orientador: João Francisco Escobedo / Banca: Eduardo Nardini Gomes / Banca: Alexandre Dal Pai / Resumo: O presente trabalho descreve a construção de um coletor solar alternativo de concreto de tração simples (areia, cimento e pedra), para aplicações agrícolas e agroindustriais. o coletor é constituído de uma área de absorção 51 m2 com 470m de mangueira de polietileno para o aquecimento da água, e o armazenador da água aquecida. O sistema coletor e armazenador foi submetido a testes experimentais onde foram determinados para as estações verão e inverno, e sob três coberturas de céu aberto, parcialmente nublada e nublada: as temperatura do absorvedor em três profundidades; ganho térmico do fluido; rendimento térmico do coletor, e desempenho do armazenador. Os resultados mostram que a temperatura do absorvedor foi maior na cobertura de céu aberto, decrescendo em seqüência de profundidade 55,74ºC, 52,10C e 49,30C respectivamente, e foi menor na cobertura de céu nublado, 48,30C, 46,20C e 44,60C respectivamente; o ganho térmico do fluido de trabalho no absorvedor foi decrescente em função do aumento comprimento do condutor: o ganho foi maior no verão e em dias de céu aberto, atingindo a temperatura máxima de 52,70C, e foi menor no inverno, em dias céu nublado, atingindo a temperatura máxima de 28,50C; o rendimento térmico do coletor foi maior em dia de céu aberto: no verão 71,4% e inverno 74%; o sistema armazenador térmico, mostrou ótimo desempenho na conservação da temperatura do fluido de trabalho. Nos dias estudados houve uma redução de 10% na temperatura final da água aquecida / Abstract: This paper describes the construction of an alternative sidewalk-type solar collector made of concrete (sand, cement and stone), for agriculture and agribusiness uses. The collector consists of an absorption area of 51 m2 with 470m polyethylene tubing for water heating, and a storage for warm water. The collector and storage systems were subjected to experimental tests which were determined for summer and winter, three sky conditions: open skies, partly cloudy and overcast; three depths temperature in the absorber; thermal gain of the fluid, thermal efficiency of the collector and performance of the water storage. The temperature of the absorber was higher in open sky conditions: 55,74ºC above it, decreasing in depth sequence of 52,1ºC and 49,3ºC. This temperatures of the absorber were 48,3ºC 46,2ºC and 44,6ºC respectively in a overcast days. The thermal gain of the working fluid in the absorber was decreasing with increasing length of the conductor: the gain was higher in summer and open sky days, reaching a maximum temperature of 52.7 ºC, and lowest in winter cloudy days, reaching a maximum temperature of 28.5 ºC. The collector thermal efficiency was higher in open sky days: 71.4% in summer and 74% in winter. The warm water storage system had excellent keeping temperature performance with 10% loss in the final water temperature / Mestre

O presente trabalho consiste em um estudo experimental sobre o efeito do controle de vazões em sistemas de aquecimento solar de água em instalações com grande número de coletores, onde o gradiente de temperatura não é suficiente para circular a água por termossifonagem. Foi avaliado o desempenho de todo o sistema sob diferentes condições de insolação, de vazão, de diferenciais de temperatura entre os coletores e o reservatório, em regime não permanente. Os resultados experimentais foram comparados com a equação de rendimento dos coletores, para condições de regime quase permanente, obtida segundo a norma da ABNT - NBR 10184/1988. Os ensaios foram realizados em duas baterias de testes, cada uma composta de dois coletores industrializados e um reservatório isolado termicamente. Em uma destas baterias, o fluxo de água entre os coletores e o reservatório ocorreu por termossifonagem, isto é, sem nenhuma restrição à vazão; na outra bateria, a vazão foi controlada por um registro e uma bomba hidráulica. Um sistema de automação coletou e processou os dados de forma a permitir a execução dos controles desejados, inclusive a simulação de consumo de água quente. O sistema com circulação natural, isto é, por termossifão, demonstrou ter uma grande habilidade de se adaptar à disponibilidade de energia com as temperaturas da água armazenada, por meio da otimização da velocidade da troca de calor. Foi desenvolvido, tomado como referência o escoamento por termossifão, um modelo de operação para sistemas diretos ativos que calcula a vazão com base no monitoramento das temperaturas das extremidades das tubulações que interligam o reservatório e os coletores, temperatura do ar, radiação solar disponível e vazão no instante anterior. O modelo foi testado experimentalmente e a operação do sistema ativo resultou em significativa melhora a eficiência. / The focus of this work is the experimental study of the effect of water control discharge in solar water-heating systems with a large number of collectors where the temperature gradient is not sufficient for thermosiphon water circulation. The performance of the system was evaluated under different conditions of solar radiation, flow rate, temperature differential between solar collectors and the storage tank and under transient conditions. The results were compared to a collector\'s performance equation of the quasi-steady-state model according to ABNT-NBR 10184/1988 standard. The tests were carried out on two systems each one constituted of two manufacturing collectors and one thermal tank. In one of these systems the flow between the collectors and storage occurred by thermosiphoning, i.e., by natural convection and without discharge restrictions. In the other, the flow control was done by means of a valve and a pump. In order to allow the execution of the desired controls, including hot water consumption, data were colleted and controlled through an automation system. The system of natural circulation shows a great ability to adaptation of disposal energy with water temperature stored, through velocity of heat exchange optimization. An operation model was developed, having thermosiphoning water circulation as reference, for active direct circulation systems that calculate the discharge taking into consideration the monitoring of the differential temperature between solar collectors and the storage tank, the air temperature, solar radiation available and the flow rate on previous time interval. This model was experimentally tested and resulted in a significant improvement in performance of the system operation.

The following master’s thesis examines the use of biothermal energy released during the decomposition process of composting. The aim of this thesis is to explain the heat generation principles of composting, to summarize its consumption possibilities, and to design a suitable use of the source for the demands of a real building. First, the theoretical framework compares various options of the biomass utilization. It then describes the biochemical course of organic matter decomposition, and conceptualizes the term thermocompost as well as different methods of heat extraction. Subsequently, it lists ways of applying this technology in practice. Second, the empirical part uses the findings to propose a compost pile installation, and its connection to the current heating and hot water system in Ecocentre Karpaty in Nová Lhota, Hodonín. Due to the low-temperature nature of the source and the mode of usage of the building, it is recommended to accumulate the heat generated in the hot water storage tank. The preheating of potable water is considered as its primary benefit. In case of sufficiently high temperature of the thermocompost, the design also includes the possibility of preheating of heating water. In conclusion, the thesis evaluates the financial costs of the project and determines the financial savings. These have – due to the low frequency of the building usage and the consumption of hot water reach – relatively low values.

The building Norra Djurgården 43:12 on the main campus of the Royal Institute of Technology (KTH)  in Stockholm will be retrofitted as students from the exter- nal campus Haninge will be moved there. This occasion is supposed to be used to improve the facility’s energy efficiency. Potential for this exists for both the space and the water heating system. The effect of decreasing the supply temperature to the radiators was examined  based on equations for the heat transfer. It was calcu- lated that lowering the supply temperature by 5 K would reduce the space heating demand by 25 %, i.e. 94.25 MWh a−1  and avoid emissions of 9.9 t CO2 a−1. Due to high heat losses from the secondary district heating circuit on KTH property to the ground, an alternative for the domestic hot water supply at times without space heating demand, i.e. from May to September, was considered.  Two systems were designed which can completely cover the demand and were evaluated in terms of both energy and economic efficiency. The daily domestic hot water demand  as well as the peak demand were modelled especially for this purpose. A system com- prising ten flat panel solar thermal collectors with a total aperture area of 23.3 m2 and an auxiliary heat pump of 7.5 kW capacity was calculated to achieve a maximum coefficient of performance (COP) of 9.13 in June. In spite of the low operation cost, the system has a negative Net Present Value as the fixed capital investment is very high. The more competitive option is the installation of a heat pump of 12.22 kW capacity which is supposed to use waste heat from the server room.  If both the cooling power and the heating  power are considered as the benefit, the Net Present Value calculates to about 274,500 SEK, otherwise it is still almost 99,000 SEK (ap- proximately 32,000 EUR and 11,500 EUR respectively).  These figures are based on an operation cycle of one year, i.e. if the heat pump contributes to the space heating supply from October to March. Compared to the use of outside air as a heat source, the COP is increased by 83 % or 10 % respectively, depending on the definition of the benefit. The reduction in the district heating demand calculated to 24.48 MWh a−1 provided the building can be disconnected from the KTH distribution network from May to September. At the same time, emissions of 2.57 t CO2 a−1  could be avoided. In conclusion, the installation of a heat pump using waste heat from the server room appears to be a solution which is both energy efficient and economical. / Das Gebäude Norra Djurgården  43:12 auf dem Hauptcampus der Königlichen Tech- nischen Hochschule (KTH)  in Stockholm wird renoviert werden, da der Vorlesungs- betrieb des externen Campus Haninge zukünftig zum Teil dort stattfinden wird. Bei dieser Gelegenheit soll die Energieeffizienz  des Gebäudes gesteigert werden. Poten- tial hierfür besteht sowohl beim Heizen als auch in der Warmwasserbereitung. Die Auswirkungen einer verringerten Vorlauftemperatur zu den Heizkörpern wurden auf Grundlage von Gleichungen zur Wärmeübertragung betrachtet. Es wurde berech- net, dass die Verringerung der Vorlauftemperatur um 5 K den Heizbedarf um 25 % reduzieren würde, d. h. um 94,25 MWh a−1, und damit Emissionen in Höhe von 9,9 t CO2 a−1 vermieden werden könnten. Aufgrund hoher Wärmeverluste vom sekundären Fernwärmekreislauf  zum Boden auf dem Gelände der KTH wurde eine Alternative  für die Warmwasserbereitung zu Zeiten ohne Heizbedarf, d.h. von Mai bis September, in Erwägung gezogen. Zwei Systeme, welche den Bedarf vollständig abdecken können, wurden entwick- elt und sowohl auf ihre Energieeffizienz  als auch auf ihre Wirtschaftlichkeit  hin geprüft. Der tägliche Warmwasserbedarf  sowie der Spitzenbedarf  wurden eigens zu diesem Zweck modelliert. Für ein Hybridsystem, welches aus zehn Flachkollek- toren mit einer gesamten Aperturfläche von 23,3 m2  und einer Wärmepumpe mit 7,5 kW Leistung besteht, wurde eine maximale Leistungszahl von 9,13 im Juni ermittelt. Trotz der geringen Betriebskosten ist der Kapitalwert negativ, da die Investitionskosten sehr hoch sind. Die konkurrenzfähige Alternative ist die Installa- tion einer Wärmepumpe mit 12,22 kW Leistung, welche die Abwärme der Computer im Serverraum nutzen soll. Werden sowohl die Kälte- als auch die Wärmeleistung als Nutzen angesehen, berechnet  sich der Kapitalwert zu etwa 32.000 EUR, ohne Miteinbeziehung der Kälteleistung zu 11.500 EUR. Diese Zahlen beziehen sich auf einen ganzjährigen Betrieb, d. h. die Wärmepumpe trägt von Oktober bis März zur Heizleistung bei. Verglichen mit der Nutzung von Außenluft als Wärmequelle kann die Leistungszahl um 83 % bzw. 10 % gesteigert werden, je nach Definition des Nutzens. Die Verringerung des Fernwärmebedarfs wurde zu 24,48 MWh a−1 berech- net, vorausgesetzt das Gebäude kann von Mai bis September vom Verteilernetz der KTH abgekoppelt werden. Gleichzeitig ermöglicht dies Emissionseinsparungen von 2,57 t CO2 a−1. Zusammenfassend erscheint  die Installation einer Wärmepumpe, welche die Abwärme im Serverraum nutzt, als eine sowohl energieeffiziente als auch wirtschaftliche Lösung. / Byggnaden Norra Djurgården  43:12 på Kungliga Tekniska Högskolans (KTH:s) hu- vudcampus i Stockholm kommer att renoveras då studenter från den externa cam- pusen Haninge kommer att  flyttas dit. Detta tillfälle  skall nu utnyttjas  för att effektivisera byggnadens energiprestation.  Potentialen för energieffektivisering finns därtill  i både uppvärmningen och varmvattenberedningen. I detta arbete har ef- fekten av sänkt tilloppstemperatur till radiatorerna studerats.  Effekten har kvan- tifierats genom beräkningarna  med hjälp av välkända ekvationer för värmetrans- port.  Beräkningarna har visat att värmebehovet kunde minskas med 25 %, d.v.s. 94,25 MWh per år, genom en sänkning av tillopstemperaturen med 5 K. Följaktigen kunde CO2 emissionerna också minskas med ungefär 9,9 ton per år. Då värmeförlusterna från den primära fjärrvärmekretsen mellan maj och september är höga, har ett alternativ  för varmvattenberedningen för denna tidsperiod pre- senterats.  Två system har presenterats som kan fullständigt täcka behovet  och har analyserats beträffande både energieffektiviteten och lönsamhet. Det dagliga varmvattenbehovet samt spetsbehovet har modellerats just för detta syfte.  Den maxmimala värmefaktorn till ett system bestående av 10 plana solfångare med en total aperturarea (genomskinliga arean) på 23,3 m−2  och en värmepump  på 7,5 kW har uppskattats till 9,13 i juni.  Trots de låga driftskostnaderna är kapitalvärdet negativt eftersom investeringskostnaderna  var höga. Den andra lösningen innefat- tade installation av en värmepump på 12,22 kW som använder sig av spillvärmen från serverrummet. Om besparingen av både fjärrvärme och fjärrkyla  betraktas i lönsamhetsanalysen, beräknas kapitalvärdet till ungefär 247.500 SEK, respektive 99.000 SEK om bara det minskade fjärrvärmebehovet  betraktas. Dessa siffror är baserade på ett års drift, d.v.s. om värmepumpen står för uppvärmningen från ok- tober till mars. Jämfört med användningen av uteluft som värmekälla  ökar värme- faktorn med 10 %. Ökningen blir 83 % om i processens nytta inkorporeras både den värme som absorberats från serverrummet och den värme som används för varm- vattenberedning  och uppvärmning. Reduktionen i fjärrvärmebehovet har beräknats till 24,48 MWh per år, förutsatt att byggnaden kan kopplas ifrån KTH:s distribu- tionsnätverk mellan maj och september.  Samtidigt kunde CO2 emissionerna också reduceras med 2,57 ton per år. Sammanfattningsvis kan det konstaterats att instal- lationen av en värmepump,  som använder sig av spillvärmen från serverrummet, kan vara både en kostnads- och energieffektiv lösning för den undersökta byggnaden.

This work studies the performance of heat pipe solar collector for water heating. Experimental results are validated using numerical modeling. Homemade heat pipes with distilled water as a working fluid were used for experimental tests. Both natural and forced convective heat pipe condensing mechanisms are studied and their results are compared with conventional natural circulation solar water heating system. Cross flow and parallel flow heat exchanger were tested in forced type heat pipe condensing mechanism. Experimental and numerical results showed good agreement. Heat pipe solar collectors outperformed conventional solar collector because of their efficient heat transport method. Forced convective heat exchanger was found to give higher efficiency compared to natural convective heat pipe condensing system. However, natural convective heat pipe condensing is free from parasitic power and low system weight. It also showed appreciable system efficiency and can be further developed to be used in rural areas where grid electricity is scarce. Cross flow and parallel flow heat exchanger have been tested for forced convective heat pipe condensing mechanism and no appreciable difference was found due to higher fluid velocity in heat exchangers.