Två olika värmesystem i två flerbostadshus har analyserats. Målet med analysen är att få en uppfattning om vilket värmesystem som är mest fördelaktigt i flerbostadshus. I analysen jämförs två olika värmesystem. I värmesystemen används två olika sorters frånluftsvärmepumpar för att återvinna värme ur frånluften. När värmepumparna inte klarar av att producera tillräckligt med värme för att täcka fastighetens värmebehov används fjärrvärme som spetsning. Värmepumparna är fastighetens huvudvärmekälla. I den ena fastigheten, Gäddan 1, används en luft-vatten frånluftvärmepump. Kylbatteriet som finns i frånluftsvärmepumpen är placerat i frånluftkammaren. Den andra fastigheten, Gäddan 2, använder sig av två utomhusvärmepumpar. Dessa två är placerade i en frånluftskammare för att kunna återvinna den varma luften.  Under analysen har en sammanställning av egna mätningar och prognoser tagits fram ur en mätningsperiod på tre veckor. I analysen jämförs de olika värmesystemen utifrån tre olika faktorer; energi, miljö och ekonomi. De parametrar som beräknats är värmefaktor (COP), energiförbrukning (kWh), livscykelkostnad (LCC), återbetalningstid (år) och kostnad för producerad värmeenergi (kr/kWh). Resultaten utgår från statistiken och jämförs mellan varandra. Resultatet av analysen visar att värmesystemet i fastigheten Gäddan 1 är mest fördelaktig enligt de metoder som har använts som berör både energi och ekonomi.  Det resultat som visats är att Gäddan 1 har 20 % högre värmefaktor, 12 % lägre driftskostnad och 50 % snabbare återbetalningstid för värmesystemet. Dock har värmesystemet 36 % högre koldioxidsutsläpp under systemets levnadslängd, som är baserat på 20 år.  I slutsatsen kan fastigheternas storlek påverka resultaten. Gäddan 1 är en större byggnad och har fler lägenheter jämfört med Gäddan 2. Detta påverkar förbrukningen av fjärrvärme i värmesystemen som ökar koldioxidsutsläppen, vilket kan vara en bidragande faktor till att Gäddan 1 har högre koldioxidsutsläpps resultat (36 %) än Gäddan 2. / Two different heating systems in two apartment buildings have been analyzed. The goal of this analysis is to get an idea of which heating system is most beneficial in apartment buildings. The analysis compares two different heating systems. Two different kinds of exhaust air heat pumps are used to recover heat from exhaust air. When heat pumps are unable to produce enough heat to cover the heating demand of the buildings, district heating is used. The heat pumps are the property's main source of heat. In one property, Gäddan 1, an air-water heat pump is used. The cooling coil located in the exhaust air heat pump is placed in the exhaust chamber. The other property, Gäddan 2, features two outdoor heat pumps. These two pumps are disposed in an exhaust chamber in order to recover the hot air. During analysis, a compilation of measurements and predictions from a measurement period of three weeks has been analyzed in order to calculate the various parameters. The analysis compares the different heating systems based on three different factors including energy, environment and economy. The parameters that are calculated are the coefficient of performance (COP), energy consumption (kWh), life cycle cost (LCC), payback period (years) and cost of the produced thermal energy (SEK / kWh). The results are based on statistics and compared between each other. The result of the analysis shows that the heating system in the property Gäddan 1 is the most beneficial, according to the methods used concerning both energy and economy. The result shows that Gäddan 1 has a 20 % higher coefficient of performance, 12 % lower operating cost and 50 % faster payback time for the heating system. However, this heating system has 36 % higher carbon dioxide emissions during its life span, which is based on 20 years. In conclusion the properties size may also affect the results. Gäddan 1 is a larger building and has more flats than Gäddan 2. This affects the consumption of district heating in the heating systems with increase carbon emissions. This may be a contributing factor to a higher carbon dioxide emission in Gäddan 1 (36 %) compare to Gäddan 2.

På grund av höga uppvärmningskostnader vill Lycksele kommun utreda de ekonomiska aspekterna av att investera i bergvärme till en fastighet som huserar vård- och omsorgsverksamhet. Fastigheten är belägen utanför Lycksele tätort vilket utesluter fjärrvärme som ett alternativ till uppvärmning. I nuläget sker uppvärmningen av fastigheten med hjälp av ett luftburet golvvärmesystem av typ Legalett som värms med elaggregat. Det huvudsakliga syftet med projektet är att avgöra om ett byte av värmesystem från direktverkande el till bergvärme är ett bra alternativ för kommunen att investera i. Genom att utföra en lönsamhetsanalys kommer lönsamheten av denna energieffektiviserande åtgärd utredas, med en förhoppning om att rapporten ska kunna hjälpa kommunen att fatta beslut angående denna typ av åtgärder även i framtiden. Genom att sammanställa fastighetsdata som samlats in med hjälp av fastighetsavdelningen på Lycksele kommun kunde fastighetens värmebehov fastställas och bergvärmesystemet dimensioneras. En varvtalsstyrd värmepump valdes för att täcka 100% av energibehovet vilket innebär ett i stort sett obefintligt behov av spetsvärme. Kostnader för bland annat borrning av bergvärme, anskaffning av värmepump samt nya vattenburna värmeaggregat beräknades och låg till grund för den lönsamhetsanalys som genomfördes. Två alternativa investeringar togs fram där skillnaden låg i värmeavgivarna. Alternativ 1 innefattar bergvärme samt anpassning av befintligt golvvärmesystem medan alternativ 2 innefattar bergvärme samt kostnader för ett nytt radiatorsystem. Uppskattningen av kostnaderna av att investera i ett nytt radiatorsystem gjordes för att ge ett alternativ som kan motverka viss problematik som upplevts med det befintliga golvvärmesystemet. Lönsamheten av de två alternativen uppskattades med hjälp av nuvärdesmetoden samt payback-metoden. Resultatet av beräkningarna innebar att kostnaden för borrning av bergvärme uppgick till ca 785 tkr, till detta tillkommer kostnaden av en värmepump, referenspumpens anskaffningsvärde var 166 tkr. Priset på nya aggregat till Legalettsystemet var 14 200 kr per aggregat. Uppskattningen av radiatorsystemets kostnad uppgick till 1,05 Mkr. Detta innebär totala investeringskostnader på just under 1,4 Mkr för alternativ 1 och på ca 2 Mkr för alternativ 2. Den lägre energianvändningen som bergvärmen möjliggör beräknades innebära ekonomiska besparingar på ca 227 tkr per år vilket innebär att payback-tiden för de två alternativens grundinvesteringar uppgår till 6,02 år för alternativ 1 och 8,8 år för alternativ 2. Då borrhålen har en längre livslängd än värmepumpen så uppskattades att värmepumpen kommer att behöva bytas två gånger under investeringens livslängd. De två alternativens nettonuvärden uppgick till ca 3,4 Mkr för alternativ 1 medan det för alternativ 2 uppgick till ca 2,7 Mkr över hela investeringens livslängd. Både nuvärdesmetoden och payback-metoden tyder på att investeringen bör vara lönsam då nettonuvärdena för de båda alternativen är positiva och payback-tiden är lägre än 20% av investeringens uppskattade livslängd. Det alternativ som ger bäst lönsamhet är alternativ 1 vilket beror på den lägre investeringskostnaden då det befintliga systemet anpassas. / Due to high heating costs, the municipality of Lycksele wants to investigate the economic aspects of investing in geothermal heating for a property that houses healthcare and care operations. The property is located outside urban area Lycksele, which excludes district heating as an alternative. At present, the property is heated by means of an air-based floor heating system of the type Legalett, which is heated by electric heaters. The main purpose of the project is to determine if a change of heating system from electrical heating to geothermal heating is a good alternative for the municipality to invest in. By conducting a profitability analysis, the profitability of the action of investing in geothermal heating will be investigated with the hope that the report will be able to help the municipality make decisions regarding these types of actions in the future. By compiling property data collected with the help of the property department of Lycksele municipality, the property's heating needs could be determined and the geothermal heating system dimensioned. An inverter-controlled ground heat pump was chosen to cover 100% of the energy demand, which means a virtually non-existent need for peak heat.  Costs for, among other things, drilling of geothermal heat, the procurement of heat pumps and new water-borne heaters were calculated and formed the basis for the profitability analysis carried out. Two alternative investment options were made where the difference were the heat emitters. Option 1 includes geothermal heating and adaptation of existing underfloor heating system, while option 2 includes geothermal heating and costs for a new radiator system. The estimate of the cost of investing in a new radiator system was made to provide an alternative that could counteract some of the problems experienced with the existing underfloor heating system. The profitability of the two alternatives was estimated using the net present value method and the payback method. The result of the calculations meant that the cost of drilling for the geothermal heat amounted to about SEK 785,000, to which the cost of a heat pump is added, the reference pump's value was SEK 166,000. The price of new units for the Legalett system was SEK 14200 per unit. The estimate of the cost of the conversion to a radiator system amounted to SEK 1.05 million. This means total investment costs of just under SEK 1.4 million for option 1 and about SEK 2 million for option 2. The lower energy consumption made possible by the geothermal heating was estimated to amount to approximately SEK 227,000 per year in economic savings, which means that the payback time for the two alternatives' basic investments is 6.02 years for options 1 and 8.8 years for option 2. Since the boreholes have a longer lifespan than the heat pump it was estimated that the heat pump will need to be replaced twice during the entire lifespan of the investment. The net present value of the two alternatives amounted to approximately SEK 3.4 million for alternative 1, while for alternative 2 it amounted to approximately SEK 2.7 million over the entire lifespan of the investment. Both the present value method and the payback method indicate that the investment should be profitable as the net present values ​​for both alternatives are positive and the payback time is less than 20% of the estimated lifespan of the investment. The alternative that provides the best profitability is option 1, which is due to the lower investment cost when adapting the existing system.

Due to desirable emission reductions and population growth, an increasing energy demand isidentified as a dire issue for energy systems. The introduction of low energy building districtsenables an increased energy system efficiency. This study’s aim is twofold. Firstly, an extensive urban building energy model is used to simulatethe yearly use and geographic distribution of the heat demand for residential and commercialbuildings that are to be supplied by a low-temperature district heating system. Two buildingenergy performance cases are studied; one where all buildings are assumed to be of PassiveHouse standard, and one where the building energy performance is in line with conventionalnew-building regulations in Sweden. The study showed that that Passive Houses will generatethe lowest yearly heat demand and that implementation of ventilation heat recovery has a bigimpact. Furthermore, the results showed that a variation of building energy performance mightbe advantageous when planning a new city district with district heating. Secondly, one specific building is in detail modeled as Passive House and according to BBR-standards and simulated in the building energy simulation software IDA ICE to investigate whatbuilding heating system is best suited for low-temperature heat supply. The temperaturedemands for floor heating and low tempered radiators is investigated and compared toconventional water-based radiators. Results showed that floor heating requires lowertemperature’s than low temperature radiators, but both are well suited for low temperaturedistrict heating. The study’s results will be used as an example for future city district planning aswell as presenting relevant heating systems for low-temperature district heating.

Valhalla is an old school building constructed in the beginning of the 20th century. Originally designed to be used as a school for girls, the building is now being used for cultural purposes and decaying. The municipality of Falun, who owns the building, wishes to restore it to the point where it meets todays modern standards and amenities, regarding indoor climate and comfort. The idea is to convert Valhalla into an office building for the employees of the municipality. Whilst doing this, a refurbishment goal set by the municipality of Falun applies where the annual amount of bought energy for the building shall be reduced by half when the refurbishment is complete. This report will evaluate the optimal solutions for Valhalla to meet the municipality’s goal. Due to the cultural protection of the building a package of appropriate suggestions will also be displayed. These suggestions are applied with the preservation of Valhalla in focus. A replica of Valhalla will be constructed in IDA ICE which is a simulation software where different energy measures can be investigated and evaluated. This is done to decide which kind of measures is profitable. By only focusing on improving the insulation to Valhalla a total energy reduction of 37.5% is achieved, which is not enough. This report will find out if the goal of reducing the annual amount of bought energy by half is achievable if geothermal heat pumps are introduced. Modern heating and ventilation systems will be installed to ensure that the indoor climate and comfort of Valhalla meets the regulations. Investigating the impact from insulation of the façade, external walls, roof, and windows and how it will improve the building. As well as applying smart controlling of the appliances and lighting, how the occupants can affect the annual electricity usage. By changing the primary heating source to a geothermal heat pump instead of the district heating already installed at Valhalla, to see the total impact in terms of both bought- and primary energy.

This work deals with the problem of choosing the correct heating curve for a certain building package (envelope plus distribution system). This topic is particularly relevant in countries like Sweden where heating curve is the most common way to control heat pumps. The analysis, involving four building models with respective distribution systems (two have floor heating and two radiators) and a variable speed GSHP, shows how, for a fixed location, the proper heating curve changes considering different building envelopes and different emitters. It is highlighted, therefore, how the adoption of a generic heating curve for all the buildings can cause discomfort and energy inefficiency. An algorithm to adjust the curve is then presented, and the results are compared with the reference case. The algorithm manages to improve comfort considerably and, for the A-class building, also SPF increases a lot (12.5%). The whole study was performed by means of TRNSYS® neglecting the DHW demand. / EffSys Expand P18: Smart Control Strategies for Heat Pump Systems

Background: Electricity tariffs charged by Eskom have sharply increased over the past three years, with a 25% annual increase approved by Nersa until April 2012. There is no indication on what to expect in the future with regard to electricity tariffs. Many South Africans are searching for ways to save on their monthly electricity bills by seeking out alternative water heating systems. Solar geysers became a popular investment option, but this might not be the best options available on the market. Purpose: The purpose of this study is to determine the most financially viable investment option in order to reduce electricity cost when it comes to water heating systems for use in households. This is done by comparing the capital expenditure and operational cost needed with the financial benefits generated by the investment, taking into consideration the size of the household. Design and method: A literature study was done on the different alternative water heating systems in order to obtain a better understanding of how these systems operate and what savings they can generate. Different investment appraisals were identified and a literature review was performed in order to identify the most appropriate investment appraisals for the purpose of this study. It was found that the net present value, equivalent annual annuity, internal rate of return, modified internal rate of return, accounting rate of return, discounted payback period and the economic value added were the best investment appraisal methods to use for the purpose of this study. Findings and conclusion: It was found that the five investment options identified in the literature review would all, to some extent, be financially viable to implement within households with high as well as low volume hot water consumption. All the investment appraisals gave positive outcomes. The conclusion was made that a saving will be generated on the monthly electricity bill no matter what alternative water heating system were to be installed in the place of a conventional geyser. Recommendations: It is recommended that a household with low volume hot water consumption should install a time switch as this investment option renders the highest IRR, MIRR, ARR and discounted payback period. The second best investment option for a household with low volume hot water consumption is a heat pump and the third best option is a gas geyser. For a household with high volume hot water consumption, the best investment options is again a time switch, as this renders the best IRR, MIRR, ARR and discounted payback period. The second best investment option is a heat pump, with a gas geyser as the third best investment option. Value of the research: This study focuses on five alternative water heating systems for a household within South Africa in times where electricity charges sharply increase. The financial viability of each of the alternatives is determined through various investment appraisals and the best option can be identified by comparing the outcomes of the alternatives. Furthermore, each individual is able to determine the viability of the alternatives by using the Excel model attached to this study and by inputting his/her own variables, where applicable. Research limitation: Limited literature was available on the different alternative water heating systems. No indication could be found of the maintenance cost of the different water heating systems. Assumptions had to be made with regard to households, although no two households are the same. Areas for further research: The same study could be performed, but with the focus on small businesses and large organisations. Furthermore, a study could be performed to determine the appropriate discount rate for individuals as well as the maintenance cost for water heating systems. / Thesis (MCom (Management Accountancy))--North-West University, Potchefstroom Campus, 2012

Den nuvarande EU-strategin för hållbar utveckling har som övergripande syfte att fastställa och utveckla åtgärder så att livskvaliteten ständigt kan förbättras, både för nuvarande och kommande generationer. En del i strategin är klimatmål som i första skedet sträcker sig till år 2020, dess medlemsstater ska då bland annat ha reducerat både sin energianvändning och sina utsläpp av växthusgaser med 20 %. I Sverige står bostad- och servicesektorn för 40 % av landets energianvändning, de har själva satt målet till 25 % besparing. Nya strategier och höjd energieffektivitet ska leda till att målet nås. Ett viktigt utvecklingsområde är uppvärmning av byggnader som står för 60 % av sektorns energianvändning. En stor del av bostadsbeståndet anses ha en energisparpotential på 20-50 %. Vid sidan av förbättringsåtgärder på bostäders klimatskal är val av värmesystem av stor vikt. Bland flerbostadshus står fjärrvärme för över 90 % av levererad värmeenergi. Genom att komplettera fjärrvärme med frånluftsvärmepump kan byggnadens energieffektivitet höjas och fastighetsägare kan göra en ekonomisk vinst i minskad mängd köpt energi. Fjärrvärmeleverantörer har svarat mot denna utveckling genom att förändra sina abonnemang så att värmesystemet blir överdimensionerat en stor del av året, därigenom blir värmepumpen överflödig. I denna fallstudie undersöks ett flerbostadshus i orten Grums, där frånluftsvärmepump redan installerats innan fjärrvärmeabonnemanget förändrades. Det nya abonnemanget innebär att fastighetsägare måste välja vilken maximal baseffekt de kan få levererad under året. En utredning är nödvändig för att säkerställa vilket val som ger en stabil och låg kostnad vid olika temperaturvariationer. Ur fastighetsägares perspektiv är problemet av ekonomisk karaktär, men denna studie undersöker även kombinationen fjärrvärme med värmepump med hänsyn till energianvändning och hållbarhetsmässig aspekt. Drivs värmesystemet på bästa sätt idag eller går det att hitta alternativa driftsätt som fungerar bättre? Målsättningen är primärt att reducera bränsleanvändning med 25 %, sekundärt minska koldioxidalstring och samtidigt sänka livscykelkostnaden för värmepumpen samt att i tredje hand reducera mängd köpt energi. Målen ska nås vid årsmedeltemperatur 5-7 ºC. För närvarande används frånluftsvärmepump som basvärme till radiatorkrets och varmvatten medan fjärrvärme täcker underskott av husets värmebehov. Nuvarande driftsätt jämförs med två alternativ. Alternativ 1 innebär byte till värmepump med mer effekt samt att fjärrvärme värmer tappvarmvatten, i övrigt körs värmesystem på samma sätt som förut. I Alternativ 2 ändras driftsätt så att fjärrvärmes baseffekt utnyttjas maximalt och värmepump körs då vald baseffekt inte täcker värmebehov. Frånsett att värmepump byts i ena fallet är inga ominstallationer nödvändiga. I studien används Microsoft Excel och varaktighetsdiagram för att utföra beräkningar. Resultaten visar att ingen av alternativen når fullständig måluppfyllelse, dock når alternativ 1 högre måluppfyllelse i och med att det primära målet (resursbesparing) i vart fall nås delvis. Studien visar att flerbostadshus, liknande referensobjektet, kan anpassa både drift av befintligt värmesystem och val av baseffekt (fjärrvärme) för att nå ekonomisk vinst. Ökad användning av fjärrvärme minskar indirekt koldioxidalstring men ökar resursanvändning. Byte av frånluftsvärmepump reducerar köpt energi vilket leder till minskad resursanvändning och bättre ekonomi, dock ökar elanvändning vilket ger marginellt tillskott av koldioxidalstring. / The overall aim of the current EU strategy Sustainable Development is to identify and develop measures to ensure that quality of life can be constantly improved, both for present and future generations. A part of the strategy is the climate targets which in the first phase extend to 2020. Its Member States shall then have reduced both their energy use and greenhouse gas emissions by 20 %. In Sweden the residential and service sector stands for 40 % of the country's energy use, they have themselves set the target to 25 % savings. New policies and improved energy efficiency will lead to completion. An important area of development is the heating of buildings, which accounts for 60 % of the sector's energy use. A large part of the housing stock is considered to have an energy savings potential of 20-50 %. Next to the improvement of the building envelope, the selection of heating system is of great importance. More than 90 % of delivered heat energy to the apartment blocks in Sweden comes from district heating. By supplementing district heating with exhaust air heat pumps, the building's energy efficiency can be increased and building owners can make a financial gain in the reduced amount of purchased energy. District heating distributers have responded to this development by changing their subscriptions, making the heating system oversized much of the year, thereby the heat pump becomes more or less redundant. In this case study, the heating system of an apartment building in the town of Grums (Sweden) is of interest. The exhaust air heat pump was already installed before the district heating subscription was changed. The new district heating subscription implicates that property owners have to choose which maximum base effect they can get delivered all year round. An investigation is necessary to ensure that the selected option provides a stable and low cost at different temperature. From the property owner's perspective, the problem is of economic nature. This study however, concentrates on the combination of district heating with heat pumps seen from the energy use and sustainability aspect. Is the heating system working in the best way today, or it is possible to find alternative modes that work better? The target with this study is to find an operational mode that primarily will reduce fuel use by 25%, secondary will lower carbon dioxide generation and cut life-cycle cost of the heat pump and thirdly will reduce the amount of purchased energy. These targets must be achieved within the annual outside temperature of 5-7 ºC. Currently the exhaust air heat pump is used as basic heat, warming up radiators and domestic hot water while district heating covers the deficit of the house's heating demand. Current operating mode is compared with two alternatives. Option 1 involves a change of the heat pump, to one with more power, district heating will heat the domestic hot water and will continuously work as a backup for the heat pump. In Option 2, the operation mode is altered to optimize use of the district heating base effect, the heat pump runs only when the selected base effect does not cover the heating demand. Apart from that the heat pump is replaced in the first case, no reinstallation is required for these options. Study calculations are made by using Microsoft Excel and duration diagrams. The results shows that none of the options reach the targets completely, however, Option 1 is closer considering that the primary goal (saving resources) is reached in part. The study shows that heating systems in apartment buildings, similar to the reference object, can be adjusted as well as the choice of base effect (district heating) in order to successfully reduce environmental effects and/or achieve financial gain. Increased use of district heating indirectly reduces carbon dioxide generation but increases resource use. Replacement of exhaust air heat pump reduces purchased energy which leads to reduced use of resources and better economy, however, will increase electricity consumption, which gives a marginal addition contribution of carbon dioxide generation.

Devido à climatização dos ambientes internos condicionar o bem estar e o conforto térmico das pessoas é que se fazem necessárias novas pesquisas que procurem potencializar as tecnologias existentes e reduzir tanto os custos de instalação quanto o consumo de energia. É sabido que os sistemas convencionais de calefação proporcionam um alto consumo de energia e uma emissão de níveis de ruído muitas vezes inaceitáveis, entretanto os sistemas radiantes ganham, a cada dia, uma maior abrangência como alternativa de climatização devido às suas vantagens comparativas com relação aos sistemas convencionais. O emprego de sistemas de calefação por piso radiante em muitos países é limitada pelo preço da instalação como consequência do elevado custo dos materiais como é o caso da fabricação das tubulações. Estas geralmente são fabricadas de polietileno ou de cobre, sendo este ultimo o que entrega um maior desempenho térmico e, por conseguinte um melhor fornecimento de energia, mas o elevado custo deste material restringe o seu uso principalmente ao setor residencial, podendo atingir um mercado maior que compreenda edifícios públicos, de escritório, escolas, hospitais, etc. Com isso, este trabalho procura reduzir a quantidade de materiais de tubulação necessários para garantir o desempenho do sistema e o conforto térmico de uma habitação aquecida com um sistema radiante. Para isto, foi desenvolvida a resolução numérica do modelo matemático da transferência de calor no interior do piso pelo método dos volumes finitos na formulação implícita e implementada em código computacional na linguagem Matlab. Para isto, foram considerados dois parâmetros fundamentais para garantir o conforto térmico da habitação que correspondem à temperatura da água e a distancia entre os tubos que compõem o sistema. A análise corresponde ao cálculo da temperatura superficial do piso para distintas temperaturas da água e distintas distâncias, obtendo resultados interessantes que permitem reduzir o custo da instalação em até um 40%. / Due to temperature control of interiors conditioning the well-being and the thermal comfort of people, it is necessary to make new researches aiming to improve the existing technologies and to reduce both installation costs and energy consumption. It is known that the use of traditional heating systems involves high energy consumption and, in some cases, unacceptable noise levels; while radiant systems are gaining a wider scope as a heating alternative due to its advantages compared to conventional systems. The use of radiant floor heating systems in Brazil is limited by installation cost due to the high price of required materials. This fact restricts the use of these systems primarily to the residential sector. However, it may be possible for this technology to reach a larger market, including public buildings, offices, schools and hospitals. Therefore, to optimize the most relevant design parameters relating to the thermal performance of the system and reduce both the amount of required materials and the system operating time, this paper elaborates on a method consisting of a high-resolution numerical mathematical model of the heat transfer within a floor using a finite control volume method with an implicit solution scheme. In this work, we consider how the properties of the materials, environmental thermal comfort factors and the performance of the system work together with the theoretical underpinnings of the heat transfer phenomenon to define the design parameters to optimize the materials and provide greater control over the energy consumption. This optimization is achieved without changing any environmental thermal comfort conditions or the well-being of the occupants. Finally, a numerical solution for the heat transfer within the floor is implemented using the computer code Matlab.

O objetivo deste trabalho é investigar o desempenho energético de dois diferentes tipos de sistemas de aquecimento de piscinas: á gás natural e por bomba de calor elétrica. Foi realizada instrumentação em duas piscinas localizadas em uma mesma academia, cada uma delas dotada de um dos tipos de sistema de aquecimento. Além destas duas piscinas, que são objeto de investigação desta pesquisa, outras quatro piscinas, localizadas cada uma em um local distinto na cidade de São Paulo, também receberam instrumentação e a coleta de dados está sendo executada através de sistemas de aquisição de dados, para posterior análise e novos trabalhos de pesquisa. Como resultados da análise das duas piscinas, obteve-se um coeficiente de desempenho - COP, médio para o sistema de aquecimento por bomba de calor igual a 4. Para o sistema a gás natural, os resultados para a eficiência global do sistema indicaram 76%, ao passo que o rendimento apenas dos aquecedores foi de 82%. As análises dos dados permitiram comprovar a influência da temperatura ambiente sobre o COP da bomba de calor. Quanto menor a temperatura do ar, menor o COP. A Temperatura do ar também mostrou forte influência sobre o consumo de energia. / The aim of this research is to investigate the energetic performance of two distinct kinds of swimming pool heating systems: gas-fired and electric heat pump. A practical instrumentation research was prepared in these two indoor swimming pools, placed in the same location. Besides these, other four swimming pool, placed each in a different ambient in the city of São Paulo also received the instrumentation so that it will be possible to run future researches, once the data is already being collected by the data loggers installed. As a result of the data analysis, it was found that the average coefficient of performance of the heat pumps studied is 4. For the natural gas fired system, the global efficiency factor was found to be 76%. The efficiency of the heaters isolated was found to be 82%. This research showed that the COP of heat pump systems has strong correlation with the air temperature. The lower the air temperature, the lower the COP. Temperature also has strong influence on the consumption of energy.

Background: Electricity tariffs charged by Eskom have sharply increased over the past three years, with a 25% annual increase approved by Nersa until April 2012. There is no indication on what to expect in the future with regard to electricity tariffs. Many South Africans are searching for ways to save on their monthly electricity bills by seeking out alternative water heating systems. Solar geysers became a popular investment option, but this might not be the best options available on the market. Purpose: The purpose of this study is to determine the most financially viable investment option in order to reduce electricity cost when it comes to water heating systems for use in households. This is done by comparing the capital expenditure and operational cost needed with the financial benefits generated by the investment, taking into consideration the size of the household. Design and method: A literature study was done on the different alternative water heating systems in order to obtain a better understanding of how these systems operate and what savings they can generate. Different investment appraisals were identified and a literature review was performed in order to identify the most appropriate investment appraisals for the purpose of this study. It was found that the net present value, equivalent annual annuity, internal rate of return, modified internal rate of return, accounting rate of return, discounted payback period and the economic value added were the best investment appraisal methods to use for the purpose of this study. Findings and conclusion: It was found that the five investment options identified in the literature review would all, to some extent, be financially viable to implement within households with high as well as low volume hot water consumption. All the investment appraisals gave positive outcomes. The conclusion was made that a saving will be generated on the monthly electricity bill no matter what alternative water heating system were to be installed in the place of a conventional geyser. Recommendations: It is recommended that a household with low volume hot water consumption should install a time switch as this investment option renders the highest IRR, MIRR, ARR and discounted payback period. The second best investment option for a household with low volume hot water consumption is a heat pump and the third best option is a gas geyser. For a household with high volume hot water consumption, the best investment options is again a time switch, as this renders the best IRR, MIRR, ARR and discounted payback period. The second best investment option is a heat pump, with a gas geyser as the third best investment option. Value of the research: This study focuses on five alternative water heating systems for a household within South Africa in times where electricity charges sharply increase. The financial viability of each of the alternatives is determined through various investment appraisals and the best option can be identified by comparing the outcomes of the alternatives. Furthermore, each individual is able to determine the viability of the alternatives by using the Excel model attached to this study and by inputting his/her own variables, where applicable. Research limitation: Limited literature was available on the different alternative water heating systems. No indication could be found of the maintenance cost of the different water heating systems. Assumptions had to be made with regard to households, although no two households are the same. Areas for further research: The same study could be performed, but with the focus on small businesses and large organisations. Furthermore, a study could be performed to determine the appropriate discount rate for individuals as well as the maintenance cost for water heating systems. / Thesis (MCom (Management Accountancy))--North-West University, Potchefstroom Campus, 2012