The diploma thesis aims to prepare a study of the cooling system of a multifunctional building with regard to climate change predicted until the middle of the 21st century. The work includes determining the heat load of refrigerated rooms and designing measures to reduce heat gains in the summer. Diploma thesis includes design of a cooling system with fan-coil units as end appliances with the necessary hydraulic calculations. A single-stage absorption cooling unit is used as the considered cooling source, to which a free cooling heat exchanger is assigned. The design of the cooling source includes the necessary hydraulic calculations and dimensioning of the system ensuring its functional operation. Part of the diploma thesis is drawing documentation of cooling technology and connection of fan-coil units.

LKAB behöver kyla till sina processer för att kunna förädla järnmalm. Ökad tillgång på elektronik och efterfrågan på komfortkyla breder ut sig i samhället idag, vilket leder till ett ökat kylbehov. Flertalet gamla kylanläggningar på LKAB i Kiruna börjar uppnå sin livslängd och behöver ersättas med nya maskiner och ny teknik. Då är utbyggnad av fjärrkylanätet som idag levererar kyla till KK4, KA3 och SAK-labb/kontor extra intressant. Istället för att ersätta gamla kylmaskiner i andra byggnader med nya kan man ansluta sig till de berörda fjärrkyalnätet. Det är ett nät där absorptionskylmaskiner och frikyla tillgodoser kylbehoven vilket även är ett bra val ur en miljömässig synpunkt då man nyttjar spillvärme. Idag klarar detta system av att leverera kyla till nuvarande kunder men frågan är hur mycket mer man kan ansluta till samma nät och vart begränsningarna ligger. Tittar man bara på kylmaskinerna ska man kunna ta ut 3MW kyla vilket är tre gånger så mycket som levereras idag. Begränsningarna ligger således inte där utan det är i de olika kretsarna till/från kylmaskinerna. I denna studie har mätvärden bakåt i tiden varit nödvändiga då endast frikyla använts under tidsperioden då detta examensarbete har utförts. Problem med loggning av data, felinställda givare och avsaknad av mätare har gjort att konkreta beräkningar uteblivit. Denna studie får ses som ett första steg mot en eventuell utökning av kylnätet. Konkreta förslag på hur man ska komma vidare för att kunna utnyttja nuvarande kylanläggnings hela potential tas upp i rapporten. Kan man i framtiden bygga ut fjärrkylnätet skulle man minska elanvändningen och underhållskostnaderna då man får ett färre antal kylmaskiner. / To refine iron ore products cooling is needed at LKAB. The increase of electronic devices and comfort cooling leads to higher cooling demands everywhere in society. Many old cooling machines soon are going to reach the end of their life span and needs to be replaced at LKAB in Kiruna. The development of the current district cooling grid is therefore interesting. Instead of replacing old machines in other buildings with new ones they can be connected to the existing grid. It is consisting of two absorption machines and free cooling and delivering cooling to the buildings KK4, KA3 and SAK-lab/office. The energy to the machines came from waste heat which is good for the efficiency and for the environment. Today the cooling system can manage the demands but how much can be connected to the grid in the future and where the limitations is for the current cooling system has yet no answer. The capacity of the absorption cooling is about 3MW and it is three times more than what is delivered today. So, the limitations are not the installed capacity but instead the different circuits in and out to the cooling machines. In this study previous measurements were important because only free cooling was used during this project. Problems with sensors, logging data and missing flowmeter made it impossible to do concrete calculations. Instead this study is a first step in the right direction to development of the district cooling system well as suggestions for future work. If the grid can be used to full potential the power consumption and the maintenance cost will decrease which is good for the environment and the economy.

Cooling towers form an important part of chilled water systems and perform the function of rejecting the heat to the atmosphere. These systems are often not operated optimally, and cooling towers being an integral part of the system present a significant area to study and determine possible energy saving measures. Operation of cooling towers in economizer mode in winter and variable frequency drives (VFDs) on cooling tower fans are measures that can provide considerable energy savings. The chilled water system analysis tool (CWSAT) software is developed as a primary screening tool for energy evaluation for chilled water systems and quantifies the energy usage of the various components and typical measures that can be applied to these systems to conserve energy, all while requiring minimum number of inputs to analyze component-wise energy consumption and incurred overall cost. A careful investigation of the current model in CWSAT indicates that the prediction capability of the model at lower wet bulb temperatures and at low fan power is not very accurate. A new model for accurate tower performance prediction is imperative, since economizer operation occurs at low temperatures and most cooling towers come equipped with VFDs. In this thesis, a new model to predict cooling tower performance is created to give a more accurate prediction of energy savings for a tower. Further the economic feasibility of having additional cooling tower capacity to allow for economizer cooling, in light of reduced tower capacity at lower temperatures is investigated.

Examensarbetet utförs under sista årets energiingenjörsstudier vid Mälardalens högskola. Med hjälp av Ramböll Västerås utfördes en energiuppföljning av energiförbrukningen vid Hälleborgs äldreboende beläget på Bäckby i Västerås åt Västerås stad. Hälleborgs äldreboende stod klart och var fullt inflyttat våren 2015. Boendet byggdes för att möta det ökade behovet av vårdplatser i Västerås kommun. Vid byggnationen ställde kommunen ett byggkrav på 60 kWh/(m2,år) köpt energi vilket var hårdare än de gällande byggkraven som gällde i Sverige vid dåvarande tidpunkt. Under projekteringen av byggnaden ändrades kravet till 70 kWh/(m2,år) viktad energi där fjärrvärmen viktas med 1 och elen med 2.  Ändringen uppkom efter att behovet av kyla kunde lösas med ett borrhålslager vilket ger möjlighet att ta tillvara på värmen som kyls bort via värmepumpar. Byggnadens värmebehov tillgodoses av både värmepumpar och fjärrvärme vilket innebär olika energikrav enligt BBR, viktningen görs för att få ett mellanting mellan kraven för byggnad med el uppvärmning och byggnad utan eluppvärmning. Examensarbetet går ut på att utreda om byggnadens energianvändning går att följa upp efter ett år i drift. Genom att försöka beräkna förbrukningen och på den vägen upptäcka problem som behöver åtgärdas till 2 årsuppföljning 2017. Det har under arbetets gång visat sig att anläggningens mätsystem inte fungerar som tänkt vad det gäller överföring mellan fastighetens mätssystem och Västerås stads mätdata hanteringssystem Momentum. Men även när mätdatainformationen skulle hämtas manuellt visades sig att det endast fanns för ett fåtal datum vilket gjorde det omöjligt att ställa upp en årsenergi. För att kontrollera att mätningen fungerade som det skulle ställdes en sammanställning upp för perioden 2015-02-22 och 2016-03-24 vilket visade att all elproduktion inte registreras i de interna mätarna. Fjärrvärmen var enda energienhet som kunde verifieras då den förbrukningen hämtades från fjärrvärmeleverantören Mälarenergi AB. Fjärrvärmeförbrukningen uppgick till 29 kWh/ kWh/(m2,år) mot projekterade 11.7 kWh/ kWh/(m2,år). För att kunna utföra en korrekt energiuppföljning och visa tappvarmvatten förbrukningen behöver fastigheten uppdateras med fler mätare. Dels behövs en mätare som mäter levererad fjärrvärmeenergi till tappvarmvattnet och det rekommenderas även att registrera en flödesmätare på tappvarmvattnet till verksamheten. Det bör även undersökas vilka elförbrukningar som inte omfattas av internmätning för att kunna skilja verksamhets- och fastighetsenergi åt. Elenergin för undermätarna var 555 406 kWh för perioden 2015-02-22 och 2016-03-24 och motsvarnade 924 025 kWh för nätägaren Mälarenergi i perioden 2015-05-01 till 2016-04-30. För att kunna utföra en balans ska undermätarna uppgå till samma förbrukning som huvudmätaren för samma mät period. Byggnaden uppfyller idag inte förutsättningar för att kunna göra en korrekt energiuppföljning. / In order to reach the 20/20 goals (meaning 20% lower energy consumption until 2020) the energy requirements on buildings must get tougher and tougher. The city of Västerås has from year 2011 set its own energy requirements on all sold estates to 60 kWh/(m2,year). When the city needed to build the new Hälleborgs elderly care center, their aim was to reach this limited energy consumption. Soon, during the planning stage, they changed this requirement to 70 kWh/(m2,year) weighted energy. The reason for this was because they were using two heating systems, one was a electric heat pump and the second was district heating. Because of higher average age in the society, the need for more elderly care centers arise even in Västerås. In the spring 2015 Hälleborgs elderly care center was completed and occupied. 2 year after the building was complete, the contractor has to do an energy monitoring and see if the goal 70 kWh/m2 is reached. In this bachelor thesis all information will be tested and the aim is to try to make a energy monitoring and figure out what needs to be done to be able to performe the energy monitoring 2017. During the work the biggest problem has been to get the right information. The system that should keep all the measured data (Momentum) was found not to have the connection to the building. When we try to pick the data by hand from the building it was not complete. So the conclusion is that the building is not ready to energy monitoring jet. This is because the building needs more time to be stable and adjust the technical systems. It also needs more points of energy measurments and flowmeters in order to get the heating water consumption. In the electric system first the net owners energy meter is installed, then the building has own meters at each electric central to separate customers consumption from building consumption. When groups of energy is summarized, it is just half of the net owners consumption. This is because some of the energy in the building is not registered. One of the electric energy’s that not is registered is the commercial kitchen, but the difference is to big that it need to be evaluated what’s missed.

Atualmente, o processamento de dados é uma operação vital para os negócios de qualquer companhia, indústria ou prestador de serviços. Entretanto, os servidores em operação, dissipam energia térmica, aquecendo o ambiente, podendo ocasionar problemas operacionais, como funcionamento inadequado, paradas operacionais e até incêndios. Por isso, é necessário um sistema de condicionamento de ar para controlar de temperatura e umidade ambiental, entretanto o consumo de energia elétrica deste sistema aumenta o custo operacional da instalação, sendo necessário minimizá-lo. Baseado neste fato, esta tese avalia a aplicação de 2 tipos de sistemas de resfriamento solar, absorção térmica solar e fotovoltaico, para reduzir o consumo do tradicional sistema elétrico com unidades de resfriamento elétricas operadas por compressão de vapor, apresentando economias, disponibilidade diária e vantagens em uma sala de missão crítica localiza genericamente, em São Paulo, Abu Dhabi, Los Angeles e Nova York. Além disto, analisa a contribuição de sistemas de resfriamento natural e seus efeitos sobre carga e consumo. As densidades de carga propostas foram de 0,5 kW?m-², 1,0 kW?m-², 2,0 kW?m-², 4,0 kW?m-² e 8,0 kW/m. Os índices locais de irradiação e temperaturas anuais baseiam-se nos dados apresentados no banco de dados da ASHRAE para as localidades. Os resultados, válidos para um ano típico e são comparados com (1) Sala de missão crítica acionada por um sistema convencional, (2) combinação de métodos de resfriamento solar, (3) combinação de técnicas solares e resfriamento natural. Por meio de estimativas anuais, calculando as contribuições dos métodos de resfriamento solar e natural, concluiu- maioria dos casos o método de absorção solar apresenta maiores vantagens de economia de energia e retorno de investimento que o método fotovoltaico, especialmente quando associado ao resfriamento natural indireto. Ao final, conclui-se que a utilização de resfriamento solar, pode atingir a 50% de economia na conta de energia e um TIR de 25%. Quando associado a sistemas de resfriamento natural, a economia pode atingir valores de 68% de economia e um TIR de 134%. Para tal deverá ser observado a carga aplicada, o valor de investimento e a curva característica da unidade de resfriamento que irá complementar a carga. / Nowadays, data processing is a fundamental operation for modern business such as banks, technology companies, and factories, among others. However, computers dissipate non-negligible amounts of heat and as the operating temperature increases, these machines cannot operate properly or, under extreme conditions, can come to a stop by overheating. Consequently, it is necessary air conditioning systems to keep the proper operating temperature as well as the room temperature itself. On the other hand, a data center air conditioning system drains a large amount of electrical energy in the installation. Based on this, this thesis evaluates two types of solar cooling system, an absorption thermal system, and a photovoltaic system, to support the traditional electric chiller system showing the energy saving, advantage over conventional cooling and day availability for this system. In addition, it analyzed free cooling system contribution and his effects on consumption. A case study is analyzed in a generic data center located in the city of São Paulo, Abu Dhabi, Los Angeles, and New York. At first, the electrical power density simulated by the computers is 0.5 kW/m², 1.0 kW/m² 2.0 kW/m², 4.0 kW/m² and 8 kW/m², that would occur in half loads or in high loads computer installations. Local solar irradiation and temperature indexes are based on the ASHRAE database. The results are valid for a typical year and are compared to (1) a conventional data center; (2) the event combination of solar cooling; (3) the event combination of solar cooling and free cooling. In conclusion, the energy savings, payback and internal rate of return for 10 years are presented. In the main cases, the solar absorption takes advantage than photovoltaic cooling, However, It must be observed the load replicated and the influence on the work curve of the chiller and the beginning investment. In conclusion, the solar cooling, especially solar absorption can achieve great advantage to installation, resulting in 50% on savings in the electric bill a return internal rate for 10 years of 25%. When it is associated with free cooling this savings can achieve 68% and return rate of 134%.

Atualmente, o processamento de dados é uma operação vital para os negócios de qualquer companhia, indústria ou prestador de serviços. Entretanto, os servidores em operação, dissipam energia térmica, aquecendo o ambiente, podendo ocasionar problemas operacionais, como funcionamento inadequado, paradas operacionais e até incêndios. Por isso, é necessário um sistema de condicionamento de ar para controlar de temperatura e umidade ambiental, entretanto o consumo de energia elétrica deste sistema aumenta o custo operacional da instalação, sendo necessário minimizá-lo. Baseado neste fato, esta tese avalia a aplicação de 2 tipos de sistemas de resfriamento solar, absorção térmica solar e fotovoltaico, para reduzir o consumo do tradicional sistema elétrico com unidades de resfriamento elétricas operadas por compressão de vapor, apresentando economias, disponibilidade diária e vantagens em uma sala de missão crítica localiza genericamente, em São Paulo, Abu Dhabi, Los Angeles e Nova York. Além disto, analisa a contribuição de sistemas de resfriamento natural e seus efeitos sobre carga e consumo. As densidades de carga propostas foram de 0,5 kW?m-², 1,0 kW?m-², 2,0 kW?m-², 4,0 kW?m-² e 8,0 kW/m. Os índices locais de irradiação e temperaturas anuais baseiam-se nos dados apresentados no banco de dados da ASHRAE para as localidades. Os resultados, válidos para um ano típico e são comparados com (1) Sala de missão crítica acionada por um sistema convencional, (2) combinação de métodos de resfriamento solar, (3) combinação de técnicas solares e resfriamento natural. Por meio de estimativas anuais, calculando as contribuições dos métodos de resfriamento solar e natural, concluiu- maioria dos casos o método de absorção solar apresenta maiores vantagens de economia de energia e retorno de investimento que o método fotovoltaico, especialmente quando associado ao resfriamento natural indireto. Ao final, conclui-se que a utilização de resfriamento solar, pode atingir a 50% de economia na conta de energia e um TIR de 25%. Quando associado a sistemas de resfriamento natural, a economia pode atingir valores de 68% de economia e um TIR de 134%. Para tal deverá ser observado a carga aplicada, o valor de investimento e a curva característica da unidade de resfriamento que irá complementar a carga. / Nowadays, data processing is a fundamental operation for modern business such as banks, technology companies, and factories, among others. However, computers dissipate non-negligible amounts of heat and as the operating temperature increases, these machines cannot operate properly or, under extreme conditions, can come to a stop by overheating. Consequently, it is necessary air conditioning systems to keep the proper operating temperature as well as the room temperature itself. On the other hand, a data center air conditioning system drains a large amount of electrical energy in the installation. Based on this, this thesis evaluates two types of solar cooling system, an absorption thermal system, and a photovoltaic system, to support the traditional electric chiller system showing the energy saving, advantage over conventional cooling and day availability for this system. In addition, it analyzed free cooling system contribution and his effects on consumption. A case study is analyzed in a generic data center located in the city of São Paulo, Abu Dhabi, Los Angeles, and New York. At first, the electrical power density simulated by the computers is 0.5 kW/m², 1.0 kW/m² 2.0 kW/m², 4.0 kW/m² and 8 kW/m², that would occur in half loads or in high loads computer installations. Local solar irradiation and temperature indexes are based on the ASHRAE database. The results are valid for a typical year and are compared to (1) a conventional data center; (2) the event combination of solar cooling; (3) the event combination of solar cooling and free cooling. In conclusion, the energy savings, payback and internal rate of return for 10 years are presented. In the main cases, the solar absorption takes advantage than photovoltaic cooling, However, It must be observed the load replicated and the influence on the work curve of the chiller and the beginning investment. In conclusion, the solar cooling, especially solar absorption can achieve great advantage to installation, resulting in 50% on savings in the electric bill a return internal rate for 10 years of 25%. When it is associated with free cooling this savings can achieve 68% and return rate of 134%.

The idea of snow cooling in this case is to save snow from winter to summer and to use it for air conditioning and for saving energy in the production of ice in hockey arenas. Today in Sweden, snow power on a large scale is used only on one place, the hospital in Sundsvall. There you’ll find a pond with 70 000 m3 of snow. The melt water in the pond is heated up while cooling down warm air from the hospital, before circulating back to the pond where it regains a low temperature passing through the snow. The idea was to examine the possibility to use such a system in Västerås, at the multiple sports arenas at Rocklunda, partly for air conditioning and partly for ice production. This work was made possible through gathering information on snow storage and on the Sundsvall snow cooling plant, by interviewing people with insight in the Sundsvall hospital and Rocklunda sports arenas and by calculating the electricity consumption, necessary amount of snow and making an LCC-analysis. For air conditioning the melt water would be used like in Sundsvall but for ice production the melt water would be used for condensing the cooling media in the heat pump at a lower temperature then it would do while cooling with air or river water during summer. Annual electricity savings of 120 and 154 MWh for the arenas were made for 2016 and 2017 when using the snow for ice production. For the air conditioning the saving were estimated to around 55 MWh per year. A snow dispatch hatch in one of the hockey arenas made an alternative to a full-scale snow cooling system. Using this hatch for temporal snow power could save up to 62 MWh per year when used for ice production and 38 MWh when used for air conditioning. The estimated costs for construction of said system proved to be too expensive for making a full-scale snow power system a reality. For ice production a storage of 103 000 m3 of snow was needed which made for a result of -57 MSEK in the LCC-analysis. For the air conditioning alone, a storage of 6 000 m3 was needed which made for a result of -4.2 MSEK. The snow dispose hatch, even without the need of snow storage, resulted in -5.9 MSEK for ice production and -1.6 MSEK for air conditioning. With more thoroughly estimations of the investment costs, together with global warming and thus bigger potential for saving energy, this might be a promising investment in the future.

Les systèmes de rafraîchissement d'air basés sur des échangeur-stockeurs composés de Matériaux à Changement de Phase (MCP) sont une alternative possible aux systèmes de climatisation pour le confort d'été dans les bâtiments. Toutefois, les performances de tels systèmes de rafraîchissement sont étroitement liées aux conditions climatiques et aux configurations des bâtiments à rafraîchir. L'objectif de ce travail de thèse est de développer un outil d'aide à la conception permettant un pré-dimensionnement optimal de systèmes de rafraîchissement d'air utilisant des MCP dès le stade de la conception préliminaire. Un modèle thermique dynamique simulant le comportement d'un échangeur-stockeur air/MCP est donc développé puis couplé à une plateforme logicielle de simulation thermique dynamique du bâtiment. Les modèles d'échangeur-stockeurs et de co-simulation sont validés à l'aide d'expériences menées sur deux prototypes d'échangeur-stockeur et la plateforme expérimentale de maison à énergie positive NAPEVOMO. Enfin un premier outil d'aide à la conception utilisant un algorithme d'optimisation est développé pour définir une configuration optimale de système maintenant le confort estival dans la maison NAPEVOMO. / Air-cooling systems using latent heat thermal energy storage (LHTES) are potential alternatives to air-conditioners for summer climate control in buildings. However, the performances of such systems are tightly linked to weather conditions and the configuration of the building to be cooled. The aim of this doctoral work is to develop a design support tool allowing optimally dimensioning an air-cooling system using phase change material at the preliminary design stage. A dynamic thermal model, simulating the behaviour an LHTES device exchanging with air, is developed and coupled with a building performance program. The LHTES and the co-simulation models are validated by comparison with experiments carried out on two prototypes of LHTES device and the experimental platform of zero energy building NAPEVOMO. Finally, a first design support tool using genetic algorithm is developed to define the optimal configuration of an air-cooling system for the summer comfort in « NAPEVOMO » house.

Kyla produceras med ett antal helt skilda metoder. Denna rapport och fallstudie tar hänsyn till fyra metoder för kylning, kompressordriven-, absorptions-, fri-, och fjärrkyla. En del i problematiken är att systemen har mycket olika tekniska utformningar och krav på fastigheten, så som geografi och närhet till stora tekniska system som fjärrvärme och fjärrkyla. Kylsystemen jämfördes för att finna vilket kylsystem som var lämpligast samt vilket som hade den mest gynnsamma taxeringen för fastigheten. Kylsystemens lämplighet bedömdes framförallt efter underhållsbehov, men även storlek och ljudnivå. Fastigheten som utgör examensarbetets studieobjekt har ett kylbehov på 150 kW, vilket attribueras ett bageri, restaurang, kontor samt kylbänkar m.fl. Dessa har ett kylbehov under framförallt fyra sommarmånader, där kylbänkar m.fl även har ett kylbehov under resterande året. Flera studier har gjorts och pekar på att kylbehovet i framtiden kommer att öka, även om en exakt prognos inte kan ges. Det är även tydligt att alla de ovan nämnda kylsystemslösningarna har en roll att spela framöver. Examensarbetet har framförallt använt sig av en litteraturstudie för att besvara frågeställningarna. För litteraturstudien användes hemsidor som Discovery och ScienceDirect. För att beräkna energiförbrukning, drifttider och total kostnad så har Microsoft Excel använts. Framförallt för kylproduktion med kompressor, där det givna referensaggregatet har fyra olika driftfall beroende på kylbehov, varav ett är kylproduktion med frikyla. För att vikta frikylans andel har klimatdata från SMHI (2020) använts. Programmet har även använts för att sammanställa de tabeller och figurer som presenteras i resultatet. Prisförslag har givits efter personliga kommunikation per e-mail och telefonintervjuer med energiproducenter och tillverkare av kylaggregat. Resultatet visade att fjärrkyla var det för studieobjektet mest lönsamma alternativet, det står även för det system som är lämpligast då det är helt underhållsfritt för kunden. Anledningen till dess lönsamhet tillskrevs framförallt dess låga investeringskostnad. Att använda Gavleån för ren frikyla visade sig inte vara möjligt då temperaturen i ån är för hög sommartid. Även absorptionskyla visade sig vara olämpligt för studieobjektet då temperaturen i det lokala fjärrvärmenätet är för låg samtidigt som investeringskostnaden blivit hög. För absorptionskyla hade ett extra system behövts installeras, vilket rapporten inte kunnat prissätta. Rapporten visar däremot att metoden att producera kyla med absorptionsaggregat har potential att under rätt förutsättningar ersätta kompressorkyla. Detta för att minska dels belastningen på elnätet samt som ett sätt att minska CO2-utsläpp globalt, genom export av elektricitet till Europa. Detta arbete visar att dagens teknik är begränsad men att framtida teknik visar sig ha potential. Rapporten fann även att vidare arbete med vinning kunnat utföras för att identifiera absorptionskylas expansionspotential. / Cooling is produced with several completely differentiated methods. This report and case study considers four different methods of cooling, vapor-compression-, absorption-, free- and district cooling. A part of the problem is that the systems have vastly different technical configuration and requirement of a facility, such as geography and vicinity to other big technical system such as district cooling and district heating. The cooling systems are compared to find the method that is most suitable and has the most beneficial assessment. The different methods suitablitiy was graded based on, noise level, size and required maintenance. The facility that constitutes this thesis study has a cooling demand of 150kW, which is attributed to a bakery, a restaurant, an office and cooling benches etc. These have a cooling demand during four summer months, where cooling benches etc also have a demand during the rest of the year. Multiple studies showcase and point out that the cooling demand will grow in the future, even if a precise prognosis is not made. It is also clear that these above-mentioned cooling systems have a continuing role to play going forward. This thesis has foremostly used a literature review to answer the research questions. For the review webpages such as Discovery and ScienceDirect was used. To calculate the energy consumption, running hours and total yearly cost Microsoft Excel was used. Especially when cool produced with the compressor unit. The reference unit has four different operating modes depending on the cooling demand, one of the modes is production with free cooling. To value the share and impact that free cooling has, Microsoft Excel is used in combination with statistical data from SMHI (2020). Microsoft Excel is also used to compile the tables and figures in the “results” section. The pricing published in this report is based on personal communications per e-mail and phone interviews with energy producers and manufacturers of different cooling units. The result of the thesis show that district cooling is the most beneficial solution for cooling the facility. As well as the most suitable system since it is completely maintenance free for a customer. The reason for its profitability is attributed to its low investment cost. Using the nearby river for free cooling was deemed impossible because of its high temperature during the summers. Using absorption cooling was also considered unsuitable for the case object because of the low temperature in the local district heating network during summer times, as well as the high investment cost required because of it. To make absorption cooling suitable an additional system for cooling the processes would have to be installed, which this report has not been able to price.

In order to reduce emissions from the building sector, which stands for than a fifth of the global energy consumption today, efficient and fossil free heating and cooling systems are of importance. This study investigates the combination of solar photovoltaic thermal collectors and ground source heat pump systems in order to regenerate energy to the ground in combination with free cooling. Research questions investigated was how techno-economically efficient a system with photovoltaic thermal collectors, ground source heat pumps and free cooling in a commercial building is. Moreover, the study evaluates what benefits and challenges such system can have. In addition, Polysun as a modeling tool was evaluated for modeling a system includingthese components. Polysun was used as a model tool to first set up a replication of an existing system in TRNSYS provided by researchers at KTH. The model was then scaled and adjusted with parameters to represent a commercial building using free cooling from Vasakronan, a Swedish property company. Photovoltaic thermal collectors were added to the model of the existing building, with two different configurations, and the heating and cooling demand of the building was varied. The results showed that a configuration with photovoltaic thermal collectors added after the evaporator side of the heat pump generated more energy to the system compared with an installation before the evaporator side of the heat pump. The possibilities of free cooling decreased with increasing number of solar collectors, due to the rise of temperature in the ground. From an economic perspective, photovoltaic thermal collectors are more expensive than photovoltaic modules, since it has an additional cost for the hydraulic system that depends on the building. However, photovoltaic thermal collectors also provide thermal energy that can help balancing borehole systems and reduce the risk for a need of additional drilling. The study performed an uncertainty and sensitivity analysis of the results, showing that the electricity price is the most sensitive parameter to the net present value of investing in photovoltaic thermal collectors. With the electricity price assumed in this study, the net present values were positive for all cases for the given interest rate and lifetime of 25 years. It was also concluded that the modeling tool Polysun has a user friendly interface where energy systems easily can be modeled. In terms of borehole configurations, there is a lack of modeling alternatives which resulted in unexpected temperature rises in the ground for the model. / Byggnadssektorn står idag för mer än en femtedel av den globala energiförbrukningen, där över hälften av energin kommer från fossila bränslen. Därför är det viktigt med effektiva och fossilfria uppvärmnings- och kylsystem för att minska utsläppen, där värmepumpar är ett bra alternativ. Denna studie undersöker kombinationen av termiska solceller och bergvärmepumpssystem i kommersiella fastigheter, med syfte att återladda energi till marken i kombination med frikyla. Syftet var att undersöka hur teknoekonomiskt effektivt ett sådant system är och vilka fördelar samt nackdelar som finns. Dessutom utvärderades modelleringsverktyget Polysun som användes föratt modellera systemen. Arbetet inleddes med att efterlikna ett befintligt system i Polysun från en tidigare studie från KTH som använt modelleringsverktyget TRNSYS. Därefter justerades detta system så att det skulle efterlikna en av Vasakronans byggnader som idag använder bergvärme och frikyla. Tre scenarier konstruerades till basmodellen där samtliga innefattade termiska solceller. Resultaten visade att antalet termiska solceller kunde minska i antal då dessa var kopplade efter förångarsidan av värmepumpen, jämfört med om de är installerade före förångarsidan av värmepumpen. Genom att öka antalet termiska solceller i systemet ökade temperaturen i borrhålen, vilket ledde till en minskad möjlig användning av frikyla. Ur ett ekonomiskt perspektiv är termiska solceller dyrare än solceller som enbart genererar elektricitet, med en extra kostnad för det hydrauliska systemet som även beror på byggnadens utformning. Dock finns det andra fördelar med termiska solceller såsom att de kan hjälpa till att balansera borrhålssystem och minska behovet för att borra ytterligare borrhål. I studien utfördes en osäkerhets- och känslighetsanalys av resultaten, vilken visade att elpriset har stor påverkan på nettonuvärdet av en investering i termiska solceller. Med det elpris som antogs i denna studie var nettovärdet positivt för alla fall med den givna kalkylräntan och livstiden för systemet. Polysun visade sig vara ett modelleringsverktyg med ett användarvänligt gränssnitt där energisystem lätt kan modelleras. När det gäller konfigurationer av borrhål finns det begränsade modelleringsalternativ, där resultaten visade oväntade temperaturstegringar för marken i modellen.