Yes / Fresh water is crucial for life, supporting human civilizations and ecosystems, and its production is one of the global issues. To cope with this issue, we evaluated the performance and cost of a solar-powered direct contact membrane distillation (DCMD) unit for fresh water production in Karachi, Pakistan. The solar water heating system (SWHS) was evaluated with the help of a system advisor model (SAM) tool. The evaluation of the DCMD unit was performed by solving the DCMD mathematical model through a numerical iterative method in MATLAB software®. For the SWHS, the simulation results showed that the highest average temperature of 55.05 ◦C and lowest average temperature of 44.26 ◦C were achieved in May and December, respectively. The capacity factor and solar fraction of the SWHS were found to be 27.9% and 87%, respectively. An exponential increase from 11.4 kg/m2 ·h to 23.23 kg/m2 ·h in permeate flux was observed when increasing the hot water temperatures from 44 ◦C to 56 ◦C. In the proposed system, a maximum of 279.82 L/day fresh water was produced in May and a minimum of 146.83 L/day in January. On average, the solar-powered DCMD system produced 217.66 L/day with a levelized water cost of 23.01 USD/m3 / This research was funded by the Researcher’s Supporting Project Number (RSP-2021/269), King Saud University, Riyadh, Saudi Arabia.

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.

The topic of this diploma thesis is to design the space and water heating system for a sport hall. The diploma thesis is divided into three chapters. The first chapter analyzes existing literature with a focus on heat transfer, pipe thermal insulation, hot water source, and existing normative and legislative requirements regarding hot water preparation. The second chapter consists of various calculations that regard the design of radiators, branch dimensioning, and design of water heating system for the target object. Additionally, this chapter contains an elaboration of a design documentation, which Detail Design Documentation. The third chapter focuses on an experimental water heating for the target object with a comparison of a centralized and decentralized water heating system.

Main target of this master´s thesis is a projection of a thermal circuit of a heating plant, which uses waste heat of a cogeneration unit with power of 1600 kWe. Electric power of a cogeneration unit is supplemented with an electric power produced from a waste heat. All heat is further used for heating in a warm water heating system. Within this thesis are executed projections of a thermal circuit of a heating plant, choice of particular devices, determination of a thermal power of devices and also determination of conditions of particular heat – transferring substances. Furthermore, design of particular devices is made, mainly for basic dimensions and heat transfer.

A matriz energética mundial atual gera inúmeros impactos ambientais e, com isso, fontes de energia alternativas são necessárias para um futuro imediato. Desta forma, a energia solar se apresenta como uma das possíveis alternativas. A energia solar, principalmente quando utilizada para o aquecimento de água, ou seja, na sua forma térmica, não apresenta impactos ambientais durante sua produção e possui um funcionamento simples. Devido aos seus benefícios, sistemas de aquecimento solar de água já são muito utilizados em diversos países e, inclusive, incentivados por leis, como na cidade de São Paulo. Mesmo este sistema já tendo sido muito estudado, quando a sua aplicação é destinada a residências unifamiliares, ainda há algumas lacunas quando se trata da aplicação em residências multifamiliares. Um exemplo de lacuna é a questão da medição individualizada dos sistemas prediais, incluindo da energia solar. Sendo assim, o objetivo da presente pesquisa é encontrar um sistema de aquecimento solar mais apropriado quanto à medição individualizada. Para tanto, são analisados, teoricamente, diferentes sistemas e suas caraterísticas. Além disso, é realizado um estudo de caso para se avaliar as características de um sistema em funcionamento em um edifício localizado na cidade de São Paulo. Utilizando-se da junção dos conhecimentos adquiridos na seção teórica e na seção prática, são simuladas algumas propostas de alternativas do sistema, visando avaliar o comportamento da produção dos mesmos em situações distintas. Ao final é possível identificar que o sistema Solar coletivo com acumulação privado e auxiliar instantâneo privado foi o que atendeu a um maior número dos requisitos gerais de sistemas de aquecimento solar e dos requisitos de individualização, e não apresentou problemas de perdas térmicas significativas, apesar de inovações, vislumbradas para um futuro próximo, terem potencial para elevar ainda mais a qualidade do sistema. / The current global energy matrix generates many environments impacts and, thereby, alternative energy sources are required by an immediate future. Indeed, solar energy is presented as one of the possible alternatives. Solar energy, as more when it heats water, or in other words, when its thermal form is used on the system, does not generate environment impacts during its use and has a simple operation. Due its benefits, solar water heating systems are already widely used in many countries and even encouraged by laws, for example in São Paulo city. Even though this system has already been studied by many scientific researches regarding its application for single family dwellings, there are some gaps when it is related to multifamily dwellings. One example of it is the individualization of the building systems aspect, including the individualization of the solar energy use. Therefore, the aim of this research is find a solar water heating system more appropriated regarding the individualization aspect. Thereunto, different systems from various places are theoretically analyzed by their characteristics. Furthermore, a study case is held to evaluate characteristics of a working system in a residential building located in São Paulo city. Using the junction of both, theoretical and practical studies, some alternative proposals are simulated to evaluate how the production of the systems are in different situations. As a conclusion, it is possible to define the system with a shared solar energy, private boiler and instantaneous auxiliary energy heating as the system that meet a larger number of the general solar heating system requirements and of the individualization requirements and do not have significative thermal loss issues, although, prospected near future innovations have potential to further improve the system.

[pt] Esta dissertação analisa aspectos da utilização da energia solar para aquecimento de água. Dois são os aspectos abordados: O primeiro é quanto à utilização de valores médios mensais ou diários de temperatura e insolação utilizados por diversos métodos de dimensionamento ou simulação de sistemas de aquecimento solar, e o segundo é a utilização de múltiplos tanques de armazenamento de água quente ao invés de um único reservatório de maior volume. Assim, este estudo tem como objetivo formular, simular e analisar diferentes cenários de configurações de sistemas de aquecimento solar de água, variando-se o número de reservatórios térmicos para um mesmo volume total do sistema. Tem-se por finalidade atender um mesmo padrão de consumo de água quente, condicionado a um mesmo perfil climático, visando otimizar a contribuição da energia solar ao sistema e consequentemente minimizar o consumo de energia auxiliar elétrica. / [en] This dissertation examines aspects of the use of solar energy for water heating. Two aspects are handled: The first is regarding the use of average monthly or daily values of temperature and insolation used by different scaling methods or simulation of solar water heating systems, and the second is the use of multiple hot water storage tanks instead of a single larger volume reservoir of water. Thus, this study aims to formulate, simulate and analyze different configurations of solar water heating systems scenarios, varying the number of thermal reservoirs for the same total volume of the system. It intends to satisfy the same standard of hot water consumption, under same climatic conditions to optimize the contribution of solar energy to the system and consequently minimize the consumption of electric auxiliary energy.

Current federal and provincial efficiency standards for residential water heating are based solely on the tested efficiency of individual water heating devices. Additional energy expended or saved as the water cycles through the home is not taken into account. This research, co-funded by British Columbia’s Ministry of Energy, Mines and Petroleum Resources (MEMPR), is a first step toward the Province’s goal of developing a new energy efficiency standard for water heating systems in new construction. This groundbreaking new standard would employ a “systems” approach, establishing guidelines for new construction based on the total energy used for water heating within the building envelope The research team has developed a Simulink computer model which, using a one-minute time-step, simulates 24-hour cycles of water heating in a single-family home. The objectives of this thesis are to use that model to simulate a variety of water heating technology combinations, and to devise methods of utilizing the resulting data to evaluate water heating systems as a whole and to quantify each system’s relative energy impact. A metric has been developed to evaluate the efficiency of the system: the system energy factor (SEF) is the ratio of energy used directly to heat water over the amount of energy drawn from conventional fuel sources. The CO2 impact of that energy draw is also considered. Data is generated for cities in three different climates around BC: Kamloops, Victoria and Williams Lake. Electric and gas-fired tank water heaters of various sizes and efficiencies are simulated, along with less traditional energy-saving technologies such as solar-assisted pre-heat and waste water heat recovery components. A total of 7,488 six-day simulations are run, each representing a unique combination of technology, load size, location and season. The resulting data is presented from a variety of angles, including the relative impacts of water heater rating, additional technology type, location and season on the SEF of the system. The interplay between SEF and carbon dioxide production is also examined. These two factors are proposed as the basis for devising performance tiers by which to rank water heating systems. Two proposals are made regarding how these tiers might be organized based on the data presented here, though any tiers will have to be re-evaluated pending data on a wider range of technology combinations. A brief financial analysis is also offered, exploring the potential payback period for various technology combinations in each location. Given current equipment and energy costs, the financial savings garnered by the increase in energy efficiency are not, in most cases, found to be sufficient to justify the expense to the homeowner from a purely fiscal perspective. Additional changes would need to take place to ensure the financial viability of these technologies before large-scale adoption of systems-based standards could be employed. / Graduate

Submitted by Andre Maitan (andremaitan@yahoo.com.br) on 2011-07-25T18:57:36Z No. of bitstreams: 1 Tese MPFE - André Raj Maitan - 93280.pdf: 894819 bytes, checksum: cd191610788a5e242005e02d0e272ee3 (MD5) / Approved for entry into archive by Gisele Isaura Hannickel (gisele.hannickel@fgv.br) on 2011-07-25T19:18:50Z (GMT) No. of bitstreams: 1 Tese MPFE - André Raj Maitan - 93280.pdf: 894819 bytes, checksum: cd191610788a5e242005e02d0e272ee3 (MD5) / Approved for entry into archive by Gisele Isaura Hannickel (gisele.hannickel@fgv.br) on 2011-07-25T19:20:01Z (GMT) No. of bitstreams: 1 Tese MPFE - André Raj Maitan - 93280.pdf: 894819 bytes, checksum: cd191610788a5e242005e02d0e272ee3 (MD5) / Made available in DSpace on 2011-07-25T19:28:19Z (GMT). No. of bitstreams: 1 Tese MPFE - André Raj Maitan - 93280.pdf: 894819 bytes, checksum: cd191610788a5e242005e02d0e272ee3 (MD5) Previous issue date: 2011-06-27 / Our target here is to understand how non observables factors on water heating choice can affect electricity usage by individual consumers. In order to understand this, we will apply a discrete/continuous model in order to understand the impact of household water heating system discrete choice on household electricity consumption, continuous choice. First it was used a LOGIT model as a way to understand which variables influence consumer discrete choice. Hereafter with Discrete model results we verified if consumer choice is relevant on electricity consumption intensity. Hausman method results demonstrated that if we do not specify discrete choice at continuous model, it will bring biased estimators to our model, this occurs due to the fact that discrete choice variable is significant and it helps to explain continuous model. Results show that we have roughly 10% differences on estimators when we ignore discrete choice. It’s important to note that this kind of miscalculation can bring a important difference on government investment decision. This work and the results obtained reinforced Dubbin and McFadden (1984) work that it was used as principal reference to this work. / O objetivo deste trabalho passa por entender o impacto dos fatores não observáveis na escolha do sistema de aquecimento de água na intensidade do consumo de eletricidade domiciliar. Para isto será aplicado um modelo discreto-contínuo para entender o efeito da escolha discreta do tipo de aquecimento de água domiciliar sobre o consumo de energia elétrica do mesmo domicílio, escolha contínua. Primeiramente foi usado um modelo LOGIT e por meio deste foram entendidos os fatores que influenciam a escolha discreta do consumidor. Com os resultados encontrados na escolha discreta, temos em um segundo momento que constatar se esta escolha é significante para a intensidade do consumo de energia elétrica. Os resultados obtidos usando o método de Hausmann demonstraram que ignorar este fator (escolha discreta) pode levar a estimadores viesados para a parte contínua do modelo, ou seja, a escolha discreta é significante e ajuda a explicar o consumo de energia elétrica domiciliar. Os resultados mostraram que temos diferenças de até 10% no estimador obtido quando ignoramos este fator. É importante notar que este tipo de falha no cálculo, pode trazer problemas na decisão e na quantidade de investimento de um país. Além disso, os resultados reforçaram e ratificaram o trabalho desenvolvido por Dubbin e McFadden (1984) que foram usados como base para o estudo.