The building sector has great potential for energy savings since it is responsible for nearly a third of the global energy use. As oil, coal and natural gas continues to hold a big share of the energy mix it is important to work towards introducing more renewable energy alternatives. For an energy supply system, it is common to use a multi-energy system to increase efficiency. By increasing efficiency and the use of renewable energies, the total energy consumption can be lowered, and emissions can be reduced.   The purpose of this thesis was to design a multi-energy supply system for a high-rise building in Germany with low emissions. This was executed by constructing a simplified design used as a reference, also referred to as option 1, and two other designs with different energy sources, called design 1 and design 2. The design layout was constructed in collaboration with Transsolar. Design 1 is using a compression chiller and is presented as three different variants, option 2, 3 and 4. The three options were created to evaluate the pros and cons of a larger cold water storage tank and sizing of the compression chiller. Design 2, option 5, is using an absorption chiller and this option was created to investigate the opportunity to use district heating. Simulations were made of the designs with the simulation tool TRNSYS and presented in graph form. Values provided from the simulations were then used to calculate emissions, investment costs and net present value over a period of 40 years. For the net present value, three different variants were presented. One without carbon costs taken into consideration, one with low carbon costs and one with high carbon costs. The result was evaluated, and comparisons were made to suggest the most sustainable option for the building.   The result of design 1, which has a natural gas boiler for peak heating demand and a compression chiller as cold energy source, shows that the chiller produces a higher capacity compared to the installed value during the summer and a lower value during the winter. The norm capacity of the chiller in design 1 was 175 kW when combined with a larger cold water storage and 410 kW with no cold water storage. Comparison of those options showed that it is economical to install a cold water storage since the investment cost of the chiller is lowered. However, it also showed that a higher capacity of the chiller lowered the need for the gas boiler, because of the parallel heating and cooling characteristic of the chiller, which reduces emissions. Another option was made with a larger cold water storage implemented and an over dimensioned capacity of 340 kW for the chiller to reduce the gas needed for heating. For the option with the 175 kW compression chiller the gas boiler needed to supply 15% of the heating load of the building, while the option with the 340 kW compression chiller needed 3% of the buildings heating load to be provided by the gas boiler. This decrease in the gas boiler dependency reduced the emissions for heating from 52 ton/year to 41 ton/year, while still having comparable cost over time with low carbon costs and lower cost with high carbon costs. Therefore, the option with an over dimensioned chiller with an implemented big cold water storage is the favourable one, since it has the lowest emissions of the options of design 1 and is economically justifiable.   Design 2 has one of lowest investment cost and the lowest emissions which was 61% lower than the reference design and 19% lower than design 1. With higher carbon costs option 5 is the cheapest, otherwise it is relatively similar to the other options. Hence, Design 2 is the system that is suggested to use for the building. / Byggnadssektorn står för nästan en tredjedel av den globala energianvändningen och har därför stor potential till energibesparing. Eftersom en stor del av energimixen består av olja, kol och naturgas är det viktigt att sträva mot att introducera mer hållbara energikällor. För ett energisystem är det vanligt att använda sig av mer än en energikälla för att öka effektiviteten. Med ökad effektivitet i kombination med förnyelsebara energikällor kan den totala energikonsumtionen, samt utsläppen, minska.   Målet var att designa ett energisystem med fler än en energikälla och låga utsläpp för ett höghus i Tyskland. För att göra det konstruerades en förenklad design, också kallad option 1, som användes som en referensdesign samt två andra designer, kallade design 1 och design 2, med olika energikällor. Designförslagen togs fram i samarbete med Transsolar. Design 1 använder sig av en kompressionskylmaskin och har tre olika varianter, option 2, 3 och 4, som gjordes för att utvärdera för- och nackdelar med en stor kallvattentank för energilagring och för att bestämma storleken på kompressionskylmaskinen. Design 2, option 5, använder sig av en absorptionskylmaskin och skapades för att undersöka möjligheten att använda sig av fjärrvärme. Simuleringar gjordes för design 1 och 2 med hjälp av simuleringsverktyget TRNSYS där resultatet presenterades i grafer. Värdena tagna från simuleringarna användes till att beräkna utsläpp, investeringskostnad och nuvärdet för den totala kostnaden över 40 år. Nuvärdet beräknades utan att ta emissionskostnader i åtanke, med en lägre emissionskostnad samt med högre emissionskostnad. Resultatet utvärderades och jämfördes för att kunna framföra ett förslag om vilket av alternativet som passar byggnaden bäst.   Resultatet från design 1, som har en naturgaspanna för att försörja toppvärmebehovet och en kompressionskylare för kylbehovet, visar att kompressionskylaren uppnår en högre kapacitet jdän den installerade kapacitet under sommaren och lägre kapacitet under vintern. För varianten med en större kallvattentank kunde kylarmaskinens kapacitet bestämmas till 175 kW medan den behövde en kapacitet på 410 kW för varianten med en liten kallvattentank. Vid jämförelse av de två varianterna visas att kostnaderna minskades för alternativet med kallvattentanken eftersom den krävde en lägre kapacitet för kompressionskylaren. Däremot visades det att utsläppen minskar vid användning av en större kylmaskin eftersom det minskar värmebehovet från gaspannan eftersom kylaren kyler och värmer parallellt när den är i drift. Den tredje varianten som både använder en stor kallvattentank samt en överdimensionerad kylare på 340 kW skapades för att minska gasanvändningen. Alternativet med en kylare på 175 kW behövde att 15% av värmebehovet kom från gaspannan, medan kylaren på 340 kW behövde att 3% av värmebehovet kom från gaspannan. Reduceringen av gasanvändningen sänkte utsläppen från 52 ton CO2-ekv./år till 41 ton CO2-ekv./år, med en jämförbar kostnad över tid med ingen eller låg emissionskostnad och lägre kostnad över tid med hög emissionskostnad. Alternativet med en stor kallvattentank och överdimensionerad kompressionskylare är därför det mest passande alternativet av design 1 eftersom den har lägst utsläpp medan den är ekonomiskt försvarbar.   Design 2 har en av de lägsta investeringskostnaderna och har lägst utsläpp som är 61% lägre än referensdesignen och 19% lägre än design 1. Med högre emissionskostnader är design 2 billigast, annars har den jämförbara kostnader. Därmed föreslås att byggnaden ska använda design 2.

A preocupação energética tem impulsionado a humanidade a buscar alternativas sustentáveis de energia. Neste contexto, os edifícios de escritórios têm um papel importante, em especial, devido ao elevado consumo de energia dos sistemas de condicionamento de ar. Para esses sistemas, a possibilidade de utilização de energia solar é uma alternativa tecnicamente possível e interessante de ser considerada, principalmente porque, quando a carga térmica do edifício é mais elevada, a radiação solar também é mais elevada. Dentre os sistemas de condicionamento de ar solar, o sistema térmico - que associa coletores solares térmicos com chiller de absorção - é o mais disseminado, na atualidade. Entretanto, dependendo do caso, outras tecnologias podem ser vantajosas. Uma opção, por exemplo, no caso de edifícios de escritórios, é o sistema elétrico - que associa painéis fotovoltaicos ao chiller convencional de compressão de vapor. Neste trabalho, para um edifício de escritórios de 20 pavimentos e 1000 m2 por pavimento, na cidade de São Paulo, no Brasil, duas alternativas de ar condicionado solar tiveram seus desempenhos energéticos analisados: o sistema térmico - com coletores solares térmicos somente na cobertura e o sistema elétrico - com painéis FV somente nas superfícies opacas das fachadas. Para isso, com o software EnergyPlus do Departamento de Energia dos Estados Unidos obteve-se as carga térmica atuantes no edifício e com a aplicação do método de cálculo de consumo de energia dos sistemas de ar condicionado solar, proposto pelo Projeto SOLAIR da União Européia, adaptado para a realidade da pesquisa, obteve-se o desempenho energético dos sistemas. Os resultados mostraram que, para o edifício de 20 pavimentos, o sistema elétrico tem o melhor desempenho energético, economizando 28% e 71% da energia elétrica que consumiria um sistema de ar condicionado convencional, em um dia de verão e de inverno, respectivamente. O sistema térmico, ao contrário, apresentou um desempenho energético ruim para o edifício estudado, consumindo, por exemplo, em um dia de verão, cerca de 4 vezes mais energia elétrica do que um sistema de ar condicionado convencional. Constatouse que isso ocorreu, pois a área coletora limitada à cobertura foi insuficiente para atender a demanda do chiller de absorção, que passou a operar com frações solares baixas, da ordem de 50% e 20%, de pico, no dia de inverno e de verão, respectivamente. Assim, constatou-se que para que o sistema térmico apresente um desempenho energético satisfatório é preciso que o edifício não seja tão alto. De fato, os resultados mostraram que somente se o edifício tivesse no máximo 2 pavimentos, o sistema térmico teria um desempenho energético melhor do que um sistema convencional. No caso de ser aplicado ao edifício térreo de 1000m2 de área, por exemplo, esse sistema economizaria aproximadamente 65% da energia elétrica do sistema convencional. Por fim, constatou-se também que o desempenho energético do sistema térmico seria elevado com a otimização da área e da tecnologia de coletores solares, com o aprimoramento do sistema de aquecimento auxiliar e com a redução da carga térmica do edifício por meio de técnicas passivas de climatização. / Energy concern has driven human kind to seek sustainable energy alternatives. In this context, office buildings have an important role, especially due to the high energy consumption of air conditioning systems. For these systems, the possibility of using solar energy is technically feasible and interesting to be considered, mainly because generally when the building thermal load is higher, the solar radiation is also higher. Among solar airconditioning systems, the thermal system - which combines solar collectors with absorption chiller - is the most widespread, nowadays. However, depending on the case, other technologies may take advantage. One option, for example, in the case of office buildings, is the electrical system - which combines photovoltaic panels with conventional vapor compression chiller. In this work, an office building of 20 floors with 1,000 m2 floor area, in Sao Paulo, Brazil, two technologies of solar air conditioning had their performance analyzed: the thermal system - presenting solar thermal collectors only on the roof and the electrical system with PV panels only on the opaque surfaces of the facades. For this, the software EnergyPlus of the United States Department of Energy obtained the building thermal load and the with the solar air conditioning energy consumption calculating method proposed by SOLAIR project of the European Union and adapted to this work, energy performance of systems was obtained. The results showed that for this building, the electrical system had the best energy performance, saving 28% and 71% of electricity that would consume a conventional air conditioning system in a summer day and a winter day, respectively. The thermal system, in contrast, showed a poor energy performance, consuming, for example, on a summer day, about four times more electricity than a conventional air conditioning system. It was found that this occurred because the collectors area limited to the roof of the building was insufficient to meet the absorption chiller demand, causing low solar fractions in the operation, of around 50% and 20% peak, in a winter day and in a summer day, respectively. Thus, in order of provide a satisfactory energy performance, the thermal system requires that the building not to be so tall. In fact, the results showed that only if the building had up to two floors, the system would perform better than a conventional system. In case of be installed in a building with the ground floor only, and floor area of 1000m2, for example, this system would save about 65% of the electricity comparing to a conventional system. Finally, it was found that this energy performance would be elevated as well with the optimization of solar collectors area and technology, with auxiliary heating system improvement and with the reduction of thermal load of the building by means of passive air conditioning techniques.

A preocupação energética tem impulsionado a humanidade a buscar alternativas sustentáveis de energia. Neste contexto, os edifícios de escritórios têm um papel importante, em especial, devido ao elevado consumo de energia dos sistemas de condicionamento de ar. Para esses sistemas, a possibilidade de utilização de energia solar é uma alternativa tecnicamente possível e interessante de ser considerada, principalmente porque, quando a carga térmica do edifício é mais elevada, a radiação solar também é mais elevada. Dentre os sistemas de condicionamento de ar solar, o sistema térmico - que associa coletores solares térmicos com chiller de absorção - é o mais disseminado, na atualidade. Entretanto, dependendo do caso, outras tecnologias podem ser vantajosas. Uma opção, por exemplo, no caso de edifícios de escritórios, é o sistema elétrico - que associa painéis fotovoltaicos ao chiller convencional de compressão de vapor. Neste trabalho, para um edifício de escritórios de 20 pavimentos e 1000 m2 por pavimento, na cidade de São Paulo, no Brasil, duas alternativas de ar condicionado solar tiveram seus desempenhos energéticos analisados: o sistema térmico - com coletores solares térmicos somente na cobertura e o sistema elétrico - com painéis FV somente nas superfícies opacas das fachadas. Para isso, com o software EnergyPlus do Departamento de Energia dos Estados Unidos obteve-se as carga térmica atuantes no edifício e com a aplicação do método de cálculo de consumo de energia dos sistemas de ar condicionado solar, proposto pelo Projeto SOLAIR da União Européia, adaptado para a realidade da pesquisa, obteve-se o desempenho energético dos sistemas. Os resultados mostraram que, para o edifício de 20 pavimentos, o sistema elétrico tem o melhor desempenho energético, economizando 28% e 71% da energia elétrica que consumiria um sistema de ar condicionado convencional, em um dia de verão e de inverno, respectivamente. O sistema térmico, ao contrário, apresentou um desempenho energético ruim para o edifício estudado, consumindo, por exemplo, em um dia de verão, cerca de 4 vezes mais energia elétrica do que um sistema de ar condicionado convencional. Constatouse que isso ocorreu, pois a área coletora limitada à cobertura foi insuficiente para atender a demanda do chiller de absorção, que passou a operar com frações solares baixas, da ordem de 50% e 20%, de pico, no dia de inverno e de verão, respectivamente. Assim, constatou-se que para que o sistema térmico apresente um desempenho energético satisfatório é preciso que o edifício não seja tão alto. De fato, os resultados mostraram que somente se o edifício tivesse no máximo 2 pavimentos, o sistema térmico teria um desempenho energético melhor do que um sistema convencional. No caso de ser aplicado ao edifício térreo de 1000m2 de área, por exemplo, esse sistema economizaria aproximadamente 65% da energia elétrica do sistema convencional. Por fim, constatou-se também que o desempenho energético do sistema térmico seria elevado com a otimização da área e da tecnologia de coletores solares, com o aprimoramento do sistema de aquecimento auxiliar e com a redução da carga térmica do edifício por meio de técnicas passivas de climatização. / Energy concern has driven human kind to seek sustainable energy alternatives. In this context, office buildings have an important role, especially due to the high energy consumption of air conditioning systems. For these systems, the possibility of using solar energy is technically feasible and interesting to be considered, mainly because generally when the building thermal load is higher, the solar radiation is also higher. Among solar airconditioning systems, the thermal system - which combines solar collectors with absorption chiller - is the most widespread, nowadays. However, depending on the case, other technologies may take advantage. One option, for example, in the case of office buildings, is the electrical system - which combines photovoltaic panels with conventional vapor compression chiller. In this work, an office building of 20 floors with 1,000 m2 floor area, in Sao Paulo, Brazil, two technologies of solar air conditioning had their performance analyzed: the thermal system - presenting solar thermal collectors only on the roof and the electrical system with PV panels only on the opaque surfaces of the facades. For this, the software EnergyPlus of the United States Department of Energy obtained the building thermal load and the with the solar air conditioning energy consumption calculating method proposed by SOLAIR project of the European Union and adapted to this work, energy performance of systems was obtained. The results showed that for this building, the electrical system had the best energy performance, saving 28% and 71% of electricity that would consume a conventional air conditioning system in a summer day and a winter day, respectively. The thermal system, in contrast, showed a poor energy performance, consuming, for example, on a summer day, about four times more electricity than a conventional air conditioning system. It was found that this occurred because the collectors area limited to the roof of the building was insufficient to meet the absorption chiller demand, causing low solar fractions in the operation, of around 50% and 20% peak, in a winter day and in a summer day, respectively. Thus, in order of provide a satisfactory energy performance, the thermal system requires that the building not to be so tall. In fact, the results showed that only if the building had up to two floors, the system would perform better than a conventional system. In case of be installed in a building with the ground floor only, and floor area of 1000m2, for example, this system would save about 65% of the electricity comparing to a conventional system. Finally, it was found that this energy performance would be elevated as well with the optimization of solar collectors area and technology, with auxiliary heating system improvement and with the reduction of thermal load of the building by means of passive air conditioning techniques.

This thesis presents work on a holistic approach for improving the overall design of solar cooling systems driven by solar thermal collectors. Newly developed methods for thermodynamic optimization of hydraulics and control were used to redesign an existing pilot plant. Measurements taken from the newly developed system show an 81% increase of the Solar Cooling Efficiency (SCEth) factor compared to the original pilot system. In addition to the improvements in system design, new efficiency factors for benchmarking solar cooling systems are presented. The Solar Supply Efficiency (SSEth) factor provides a means of quantifying the quality of solar thermal charging systems relative to the usable heat to drive the sorption process. The product of the SSEth with the already established COPth of the chiller, leads to the SCEth factor which, for the first time, provides a clear and concise benchmarking method for the overall design of solar cooling systems. Furthermore, the definition of a coefficient of performance, including irreversibilities from energy conversion (COPcon), enables a direct comparison of compression and sorption chiller technology. This new performance metric is applicable to all low-temperature heat-supply machines for direct comparison of different types or technologies. The achieved findings of this work led to an optimized generic design for solar cooling systems, which was successfully transferred to the market.