Load and Season Adapted Solar Collectors

In Sweden solar irradiation and space heating loads are unevenly distributed over the year. Domestic hot water loads may be nearly constant. Test results on solar collector performance are often reported as yearly output of a certain collector at fixed temperatures, e g 25, 50 and 75 C. These data are not suitable for dimensioning of solar systems, because the actual performance of the collector depends heavily on solar fraction and load distribution over the year.At higher latitudes it is difficult to attain high solar fractions for buildings, due to overheating in summer and small marginal output for added collector area. Solar collectors with internal reflectors offer possibilities to evade overheating problems and deliver more energy at seasons when the load is higher. There are methods for estimating the yearly angular irradiation distribution, but there is a lack of methods for describing the load and the storage in such a way as to enable optical design of season and load adapted collectors.This report describes two methods for estimation of solar system performance with relevance for season and load adaption. Results regarding attainable solar fractions as a function of collector features, load profiles, load levels and storage characteristics are reported. The first method uses monthly collector output data at fixed temperatures from the simulation program MINSUN for estimating solar fractions for different load profiles and load levels. The load level is defined as estimated yearly collector output at constant collector temperature divided be yearly load. This table may examplify the results:CollectorLoadLoadSolar Improvementtypeprofile levelfractionover flat plateFlat plateDHW 75 %59 %Load adaptedDHW 75 %66 %12 %Flat plateSpace heating 50 %22 %Load adaptedSpace heating 50 %28 %29 %The second method utilises simulations with one-hour timesteps for collectors connected to a simplified storage and a variable load. Collector output, optical and thermal losses, heat overproduction, load level and storage temperature are presented as functions of solar incidence angles. These data are suitable for optical design of load adapted solar collectors. Results for a Stockholm location indicate that a solar combisystem with a solar fraction around 30 % should have collectors that reduce heat production at solar heights above 30 degrees and have optimum efficiency for solar heights between 8 and 30 degrees.

Active cooling of low-concentrating hybrid PV/Thermal collectors

A series of measurements on the performance of solar cell string modules with low-concentrating CPC reflectors with a concentration factor C ˜ 4X have been carried out. To minimise the reduction in efficiency due to high cell temperatures, the modules were cooled. Four different way of cooling were tested:1) The thermal mass of the module was increased, 2) passive air cooling was used by introducing a small air gap between the module and the reflector, 3) the PV cells were cooled by a large cooling fin, 4) the module was actively cooled by circulating cold water on the back. The best performance was given with the actively cooled PV module which gave 2,2 times the output from a reference module while for the output from the module with a cooling fin the value was 1,8.Active cooling is also interesting due to the possibility of co-generation of thermal and electrical energy which is discussed in the paper. Simulations, based on climate data from Stockholm, latitude 59.4°N, show that there are good prospects for producing useful temperatures of the cooling fluid with only a slightly reduced performance of the electrical fraction of the PV thermal hybrid system.

Experimental performance of a string module in a CPC reflector cavity

The purpose of the work is to develop a cost effective semistationary CPC concentrator for a string PV-module. A novel method of using annual irradiation distribution diagram projected in a north-south vertical plane is developed. This method allows us easily to determine the optimum acceptance angle of the concentrator and the required number of annual tilts. Concentration ranges of 2-5x are investigated with corresponding acceptance angles between 5 and 15°. The concentrator should be tilted 2-6 times per year. Experiments has been performed on a string module of 10 cells connected in a series and equipped with a compound parabolic concentrator with C = 3.3X. Measurement show that the output will increase with a factor of 2-2.5 for the concentrator module, compared to a reference module without concentrator. If very cheap aluminium reflectors are used the costs for the PV-module can be decreased nearly by a factor of two.

A proposed Model for Country Branding : an experimental Application on Nigeria

In the era of globalization, countries compete with each other for attention, respect and trust of potential consumers, investors, tourists, media and governments of other nations. Branding is the most powerful tool that a nation can utilize for effective differentiation strategies and for creating competitive advantage over other nations. Unfortunately, not every nations or destination marketers have a broad understanding of the concept of branding and how a country can be successfully branded. Hence, this study has proposed a model that could be used as a valuable guide for country branding. Also the model is recommended for countries struggling with image crisis; on the mission to improve the image internationally. Nigeria is a good example of countries with image crisis; it is one of the most populated countries in the world with a population of about 160 million inhabitants and growth rate of 2.553percent annually. Despite the abundant resources (e.g. coal, petroleum, natural gas etc.) that the nation is endowed with, it is quite disappointing that the population below poverty line is still at the alarming rate of 70percent of the total population. The mismanagement and poor leadership of the nation characterised by corruption, fraud, embezzlement of public fund etc. has culminated into serious image crisis that is slowing down the potential for investment and economic growth. However, there has been series of image rebranding campaigns but no tangible achievement has been recorded. It is quite questionable though, if image rebranding will provide the kind of future that Nigeria envisaged, considering the socio-political situation and the economic imbalance; compounded by the obvious fact that the nation has no known brand. Therefore, this paper argues that there is need to redirect the effort invested on image rebranding to the creation of a unique and competitive brand for the country. It was established from the study that a nation’s brand is capable of improving the reputation of the nation as well as stimulate the expectation of the target audience. However, it was also established from the study that a wrong approach to branding could mislead the target audience and attract negative publicity. Hence, as a contribution of the study to the field of branding, a model was proposed as a functional guide for country branding. Also, considering the abysmal performance of Nigeria’s image in the international community and to strengthen the argument that brand creation is required for the country; an experimental application of the proposed model was conducted using Nigeria as the case country. The first phase of the model suggested a major improvement in the society; this is required to further enhance the strengths of the country and to motivate the much needed community participation and confidence in the brand creation. It is the conclusion of the study that a strong nation brand can offset the image problem if it is built on something concrete, genuine, and uniquely identifiable with the country, capable of connecting to the cognitive psychology of the target audience.

Variabeltryck med inkjet i dagspress : Möjligheten att införa anpassade upplagor

På uppdrag av Tidningsutgivarna har en studie utförts angående olika möjligheter att införa tryck av variabeldata med tryckmetoden inkjet i svensk dagspress. Målet var att undersöka tekniska möjligheter och begränsningar samt att utreda om det fanns något intresse på marknaden som skulle kunna ge någon avkastning. Studien utfördes med hjälp av noggranna källstudier och ett fortlöpande samarbete med olika företag med intresse för dagspress. Rapporten beskriver också företag som arbetar med den här typen av innovationer idag och diverse tidigare projekt med variabeltryckta tidningar. Nya teknologier som eventuellt kan vara av intresse för framtida utveckling har också beskrivits och hur tidningens framtid kommer att se ut ur ett kortare och ett längre perspektiv. Studien visar att inkjetpressar inte klarar av den hastighet som de moderna tidningspressarna håller idag. Men i takt med minskade upplagor och utvecklad teknologi, samt ett stort marknadsmässigt intresse så tyder det på att det kommer att finnas möjlighet att tillverka anpassade digitaltryckta tidningsupplagor inom en överskådlig framtid. Inkjet kan fungera som ett bra komplement till offset. Inlinepressar ger möjligheten att införa variabeltryck i stora tidningsupplagor medan separata inkjetpressar passar bra för tryck av mindre lokala upplagor.

Design and assessment of a large commercial Photovoltaic System in Barbados

One of the main aims of this thesis is to design an optimized commercial Photovoltaic (PV) system in Barbados from several variables such as racking type, module type and inverter type based on practicality, technical performance as well as financial returns to the client. Detailed simulations are done in PVSYST and financial models are used to compare different systems and their viability. Once the preeminent system is determined from a financial and performance perspective a detailed design is done using PVSYST and AutoCAD to design the most optimal PV system for the customer. In doing so, suitable engineering drawings are generated which are detailed enough for construction of the system. Detailed cost with quotes from relevant manufacturers, suppliers and estimators become instrumental in determining Balance of System Costs in addition to total project cost. The final simulated system is suggested with a PV capacity of 425kW and an inverter output of 300kW resulting in an array oversizing of 1.42. The PV system has a weighted Performance Ratio of 77 %, a specific yield of 1467 kWh/kWp and a projected annual production of 624 MWh/yr. This system is estimated to offset approximately 28 % of Carlton’s electrical load annually. Over the course of 20 years the PV system is projected to produce electricity at a cost of $0.201USD/kWh which is significantly lower than the $0.35 USD/kWh paid to the utility at the time of writing this thesis. Due to the high cost of electricity on the island, an attractive Feed-In-Tariff is not necessary to warrant the installation of a commercial System which over a lifetime which produces electricity at less than 60% of the cost to the user purchasing electricity from the utility. A simple payback period of 5.4 years, a return on investment of 17 % without incentives, in addition to an estimated diversion of 6840 barrels of oil or 2168 tonnes of CO2 further provides compelling justification for the installation of a commercial Photovoltaic System not only on Carlton A-1 Supermarket, but also island wide as well as regionally where most electricity supplies are from imported fossil fuels.