System Integration of PV/T Collectors in Solar Cooling Systems

The demand for cooling and air-conditioning of building is increasingly ever growing. This increase is mostly due to population and economic growth in developing countries, and also desire for a higher quality of thermal comfort. Increase in the use of conventional cooling systems results in larger carbon footprint and more greenhouse gases considering their higher electricity consumption, and it occasionally creates peaks in electricity demand from power supply grid. Solar energy as a renewable energy source is an alternative to drive the cooling machines since the cooling load is generally high when solar radiation is high. This thesis examines the performance of PV/T solar collector manufactured by Solarus company in a solar cooling system for an office building in Dubai, New Delhi, Los Angeles and Cape Town. The study is carried out by analyzing climate data and the requirements for thermal comfort in office buildings. Cooling systems strongly depend on weather conditions and local climate. Cooling load of buildings depend on many parameters such as ambient temperature, indoor comfort temperature, solar gain to the building and internal gains including; number of occupant and electrical devices. The simulations were carried out by selecting a suitable thermally driven chiller and modeling it with PV/T solar collector in Polysun software. Fractional primary energy saving and solar fraction were introduced as key figures of the project to evaluate the performance of cooling system. Several parametric studies and simulations were determined according to PV/T aperture area and hot water storage tank volume. The fractional primary energy saving analysis revealed that thermally driven chillers, particularly adsorption chillers are not suitable to be utilizing in small size of solar cooling systems in hot and tropic climates such as Dubai and New Delhi. Adsorption chillers require more thermal energy to meet the cooling load in hot and dry climates. The adsorption chillers operate in their full capacity and in higher coefficient of performance when they run in a moderate climate since they can properly reject the exhaust heat. The simulation results also indicated that PV/T solar collector have higher efficiency in warmer climates, however it requires a larger size of PV/T collectors to supply the thermally driven chillers for providing cooling in hot climates. Therefore using an electrical chiller as backup gives much better results in terms of primary energy savings, since PV/T electrical production also can be used for backup electrical chiller in a net metering mechanism.

Frånluftsåtervinning i ett äldre flerfamiljehus : Hovgården - Borlänge

I detta examensarbete undersöktes möjligheten att installera värmeåtervinningssystem för ett flerfamiljehus i Hovgården som ligger en bit utanför Borlänge. I rapporten redovisas två olika sätt för energibesparingar som är aktuella för att ersätta borttagning av oljepannan som används i huset i dag. En rad svårigheter dök upp under undersökningen för installation av nytt värmesystem. Lämpliga lösningar kunde hittas efter mycket analys. Syftet med rapporten var att undersöka möjligheten och lönsamheten för installation av något av följande system; FVP eller VBX-modul som kan återvinna värme ur frånluften. Undersökningen visade att varken VBX eller FVP kan ersätta oljepannans värmeavgivning på ett tillfredsställande sätt. Med VBX ökas COP från 2,8 till 3,11 vilket leder till 17 MWh/år elbesparing. Däremot FVP kan försörja huset med 59 MWh/år men kan inte täcka effektbehovet för gården under kallaste dagarna. Resultatet blev att de båda undersökta systemen inte har möjlighet att ersätta oljeeldning.

Essays on growth and environment

This thesis consists of a summary and four self-contained papers. Paper [I] Following the 1987 report by The World Commission on Environment and Development, the genuine saving has come to play a key role in the context of sustainable development, and the World Bank regularly publishes numbers for genuine saving on a national basis. However, these numbers are typically calculated as if the tax system is non-distortionary. This paper presents an analogue to genuine saving in a second best economy, where the government raises revenue by means of distortionary taxation. We show how the social cost of public debt, which depends on the marginal excess burden, ought to be reflected in the genuine saving. We also illustrate by presenting calculations for Greece, Japan, Portugal, U.K., U.S. and OECD average, showing that the numbers published by the World Bank are likely to be biased and may even give incorrect information as to whether the economy is locally sustainable. Paper [II] This paper examines the relationships among per capita CO2 emissions, per capita GDP and international trade based on panel data spanning the period 1960-2008 for 150 countries. A distinction is also made between OECD and Non-OECD countries to capture the differences of this relationship between developed and developing economies. We apply panel unit root and cointegration tests, and estimate a panel error correction model. The results from the error correction model suggest that there are long-term relationships between the variables for the whole sample and for Non-OECD countries. Finally, Granger causality tests show that there is bi-directional short-term causality between per capita GDP and international trade for the whole sample and between per capita GDP and CO2 emissions for OECD countries. Paper [III] Fundamental questions in economics are why some regions are richer than others, why their growth rates differ, whether their growth rates tend to converge, and what key factors contribute to explain economic growth. This paper deals with the average income growth, net migration, and changes in unemployment rates at the municipal level in Sweden. The aim is to explore in depth the effects of possible underlying determinants with a particular focus on local policy variables. The analysis is based on a three-equation model. Our results show, among other things, that increases in the local public expenditure and income taxe rate have negative effects on subsequent income income growth. In addition, the results show conditional convergence, i.e. that the average income among the municipal residents tends to grow more rapidly in relatively poor local jurisdictions than in initially “richer” jurisdictions, conditional on the other explanatory variables. Paper [IV] This paper explores the relationship between income growth and income inequality using data at the municipal level in Sweden for the period 1992-2007. We estimate a fixed effects panel data growth model, where the within-municipality income inequality is one of the explanatory variables. Different inequality measures (Gini coefficient, top income shares, and measures of inequality in the lower and upper part of the income distribution) are examined. We find a positive and significant relationship between income growth and income inequality measured as the Gini coefficient and top income shares, respectively. In addition, while inequality in the upper part of the income distribution is positively associated with the income growth rate, inequality in the lower part of the income distribution seems to be negatively related to the income growth. Our findings also suggest that increased income inequality enhances growth more in municipalities with a high level of average income than in municipalities with a low level of average income.

Ubiquitous computing in education : a SWOT analysis by students and teachers

Learning from anywhere anytime is a contemporary phenomenon in the field of education that is thought to be flexible, time and cost saving. The phenomenon is evident in the way computer technology mediates knowledge processes among learners. Computer technology is however, in some instances, faulted. There are studies that highlight drawbacks of computer technology use in learning. In this study we aimed at conducting a SWOT analysis on ubiquitous computing and computer-mediated social interaction and their affect on education. Students and teachers were interviewed on the mentioned concepts using focus group interviews. Our contribution in this study is, identifying what teachers and students perceive to be the strength, weaknesses, opportunities and threats of ubiquitous computing and computer-mediated social interaction in education. We also relate the findings with literature and present a common understanding on the SWOT of these concepts. Results show positive perceptions. Respondents revealed that ubiquitous computing and computer-mediated social interaction are important in their education due to advantages such as flexibility, efficiency in terms of cost and time, ability to acquire computer skills. Nevertheless disadvantages where also mentioned for example health effects, privacy and security issues, noise in the learning environment, to mention but a few. This paper gives suggestions on how to overcome threats mentioned.

Strategier som kan förbättra sjuksköterskors kommunikation vid överrapportering inom somatisk slutenvård : En litteraturöversikt

Bakgrund: Sjuksköterskor har i sitt dagliga arbete till uppgift att ge och ta emot rapport om patienterna hen vårdar. En god kommunikation krävs för att säkerställa att relevant information förmedlas och inte patientsäkerheten hotas. Syfte: Att beskriva strategier för hur kommunikationen kan förbättras vid överrapportering mellan sjuksköterskor inom den somatiska slutenvården. Metod: Litteraturöversikten är baserad på 15 vetenskapliga artiklar med kvalitativ, kvantitativ och mixad ansats. Artiklarna identifierades via sökningar i databaserna Cinahl, PubMed och Web of Science. Resultat: Tre strategier framkom: personlig överrapportering, användandet av standardiserade formulär och överrapportering vid patientens säng. Strategierna gav en effektivare, säkrare och mer tidssparande överrapportering. Slutsats: En god kommunikation mellan sjuksköterskorna är oerhört viktigt för att bibehålla en trygg och säker vård för patienterna. För att få en förbättrad kommunikation mellan sjuksköterskor vid överrapportering kan olika strategier användas. Då sjuksköterskorna ofta har en hög arbetsbelastning så krävs det att överrapporteringarna är strukturerade för att inte tappa bort viktig information.

Evaluation of a thermally driven heat pump for solar heating and cooling applications

Exploiting solar energy technology for both heating and cooling purposes has the potential of meeting an appreciable portion of the energy demand in buildings throughout the year. By developing an integrated, multi-purpose solar energy system, that can operate all twelve months of the year, a high utilisation factor can be achieved which translates to more economical systems. However, there are still some techno-economic barriers to the general commercialisation and market penetration of such technologies. These are associated with high system and installation costs, significant system complexity, and lack of knowledge of system implementation and expected performance. A sorption heat pump module that can be integrated directly into a solar thermal collector has thus been developed in order to tackle the aforementioned market barriers. This has been designed for the development of cost-effective pre-engineered solar energy system kits that can provide both heating and cooling. This thesis summarises the characterisation studies of the operation of individual sorption modules, sorption module integrated solar collectors and a full solar heating and cooling system employing sorption module integrated collectors. Key performance indicators for the individual sorption modules showed cooling delivery for 6 hours at an average power of 40 W and a temperature lift of 21°C. Upon integration of the sorption modules into a solar collector, measured solar radiation energy to cooling energy conversion efficiencies (solar cooling COP) were between 0.10 and 0.25 with average cooling powers between 90 and 200 W/m2 collector aperture area. Further investigations of the sorption module integrated collectors implementation in a full solar heating and cooling system yielded electrical cooling COP ranging from 1.7 to 12.6 with an average of 10.6 for the test period. Additionally, simulations were performed to determine system energy and cost saving potential for various system sizes over a full year of operation for a 140 m2 single-family dwelling located in Madrid, Spain. Simulations yielded an annual solar fraction of 42% and potential cost savings of €386 per annum for a solar heating and cooling installation employing 20m2 of sorption integrated collectors.

Making Energy Interventions more Effective : Situation, Interaction, and Precondition

A main purpose of this paper is to propose to policy makers, building professionals, and other non-social scientists a way to make energy interventions more culturally informed and, thereby, more effective. The case study on house purchasers gives an ample illustration of the richer results that can be achieved by paying attention to three aspects of energy efficiency initiatives: the contexts and situations of choice in each particular case, the interaction among relevant social actors, and the culture-specific preconditions for choice. Research on how purchasers of new pre-fabricated houses in Sweden choose their heating system show how such decisions tend to fall between two stools. Furthermore, the organizational structure of housing companies frames house purchasers' decision making. An important result is that energy saving or conversion measures must be promoted at an early stage amongst those who plan and construct buildings (rather than later amongst dwellers and energy end users).

Effective Data Management Enables Intelligent Utility Management

Instrumentation and automation plays a vital role to managing the water industry. These systems generate vast amounts of data that must be effectively managed in order to enable intelligent decision making. Time series data management software, commonly known as data historians are used for collecting and managing real-time (time series) information. More advanced software solutions provide a data infrastructure or utility wide Operations Data Management System (ODMS) that stores, manages, calculates, displays, shares, and integrates data from multiple disparate automation and business systems that are used daily in water utilities. These ODMS solutions are proven and have the ability to manage data from smart water meters to the collaboration of data across third party corporations. This paper focuses on practical, utility successes in the water industry where utility managers are leveraging instantaneous access to data from proven, commercial off-the-shelf ODMS solutions to enable better real-time decision making. Successes include saving $650,000 / year in water loss control, safeguarding water quality, saving millions of dollars in energy management and asset management. Immediate opportunities exist to integrate the research being done in academia with these ODMS solutions in the field and to leverage these successes to utilities around the world.

Can Open Access Save Us?

Just about every time I open a journal or read a blog online, I see something about e-books saving newspapers and magazines. Both magazines and newspapers–and really all scholalry communication–are going the way of all flesh, we’re told, but e-book reading may provide a stay of execution, however short that may be. It got me to thinking if there might be something else that would provide a similarDies Irae proroguement for scholarly communication in general. That’s when it occurred to me it could well be open access (OA), or at least as I envision it here.

Consumption smoothing in Latin America: an empirical assessment of present value models

The study aims to assess the empirical adherence of the permanent income theory and the consumption smoothing view in Latin America. Two present value models are considered, one describing household behavior and the other open economy macroeconomics. Following the methodology developed in Campbell and Schiller (1987), Bivariate Vector Autoregressions are estimated for the saving ratio and the real growth rate of income concerning the household behavior model and for the current account and the change in national cash ‡ow regarding the open economy model. The countries in the sample are considered separately in the estimation process (individual system estimation) as well as jointly (joint system estimation). Ordinary Least Squares (OLS) and Seemingly Unrelated Regressions (SURE) estimates of the coe¢cients are generated. Wald Tests are then conducted to verify if the VAR coe¢cient estimates are in conformity with those predicted by the theory. While the empirical results are sensitive to the estimation method and discount factors used, there is only weak evidence in favor of the permanent income theory and consumption smoothing view in the group of countries analyzed.

The Brazilian 1994 stabilization plan: an analytical view

The Real Plan has succeeded in stabilizing the Brazilian inflation. The consumer price inflation has been reduced from 11260 percent per year, in June 1994, to an estimate of 8 percent in 1997. The lower inflation resulted in a remarkable income distribution, and in an increased private consumption. The plan managed to control the inflationary effects of the increased demand with some traditional measures: A more liberalized economy, a moving (and overvalued) exchange rate band, high interest rate differentials, and a tight domestic credit policy. The government has, so far failed to accomplish the fiscal adjustment. The price stabilization has largely depended on the current account deficit. However, macroeconomic indicators do not present reasons for concern about the current account sustainability, in the medium-run. The economy may be trapped in a low-growth vicious cycle, represented by a stop-and-go trend, due to the two-way endogencity between domestic saving and growth. Economic growth depends on policies in increase the public sector saving, to secure the privatization of the State enterprises, and to promote investments. The major problem for the government action is, as always, in the political sphere. Approximately 80 percent of the Central Government net revenue are allocated to the social sectors. Consequently, the fiscal reform will hue to deal with the problem of re-designing the public sector’s intervention in the social area. Most probably, it will be inevitable to cut the social area budget. This is politically unpleasant.

Os efeitos da política monetária sobre a poupança financeira, o emprego, a produção e o consumo: 1990-1996

Este trabalho tem por objetivo estimar o tempo que diferentes segmentos econômicos levam para responder a mudanças na taxa de juros. A investigação abrangeu o período de janeiro de 1990 a junho de 1996, compreendendo, portanto, o Plano Collor e os dois anos iniciais do Plano Real. O intuito de medir essa defasagem temporal prende-se ao fato de que, no Brasil, tornou-se hábito adotar, como parâmetros de tempo de resposta à política monetária, aqueles encontrados nos Estados Unidos. Naquele país, o tempo de reação da sociedade à política monetária tem sido estimado, freqüentemente, entre 6 e 12 meses. Este estudo encontrou que, no Brasil, dependendo do segmento (poupança, consumo ou produção), o tempo de resposta é imediato, podendo chegar a 2 ou 3 meses. Para estimar a defasagem de tempo, foi usada a técnica de correlações cruzadas entre variáveis pré-filtradas pelos respectivos ARIMAS.

Efeitos dinâmicos de programas de estabilização

Com o emprego do modelo de dois setores de acumulação ótima de capital em economia aberta, determina-se o impacto sobre a trajetória do câmbio, dos salários, do investimento, da poupança e, portanto, da dívida externa e do estoque de capital, de uma elevação permanente e não antecipada da produtividade da economia. Em geral, após um choque positivo permanente de produtividade há redução da poupança, piora do balanço de pagamentos em transações correntes e valorização do câmbio. Todos fenômenos que do ponto de vista do modelo são de equilíbrio intertemporal, conseqüência da elevação da renda permanente e do excesso de demanda por bens domésticos que sucede o ganho de produtividade. Supondo que os programas de estabilização elevaram a produtividade da economia é possível com a estrutura analítica construída racionalizar qualitativamente os fenômenos observados após estes planos.

Estabilidade institucional, credibilidade e poupança privada: uma análise de economia política

O objetivo desta pesquisa é mostrar que há uma relação positiva entre a estabilidade política-institucional, a credibilidade e a taxa de poupança privada. Parte da literatura recente sobre disparidades entre taxas de poupança usa um argumento de economia política para explicar como a instabilidade política-institucional pode afetar as decisões públicas que determinam a poupança pública, mas não sugere da mesma forma que tal instabilidade pode atingir negativamente a poupança privada. Analisar-se-á esta lacuna da teoria partindo-se do referencial teórico da Nova Economia Institucional (NEI), onde salienta-se, nos processos de decisão privada de acumulação de ativos, o papel do governo gartantindo (i) a estabilidade das regras de mercado e (ii) os direitos de propriedade. A pesquisa envolverá uma análise teórica microeconômica da determinação da poupança privada usando a visão da NEI. O interesse prático fundamental da pesquisa é tentar justificar, em parte, os baixos níveis de poupança na América Latina usando um argumento institucionalista e, desta forma, propor ações de governo e reformas.

Estabilidade política, poupança privada e crescimento: teoria e evidência

O objetivo desta pesquisa é mostrar empiricamente que há uma relação positiva entre a estabilidade política-institucional e a poupança. Em primeiro lugar, a pesquisa procura aprofundar, vis-à-vis a literatura contemporânea sobre o tema, a análise teórica microeconômica da determinação da poupança privada, levando em consideração argumentos derivados da Nova Economia Institucional. Em segundo lugar, a pesquisa envolve seis testes em cross-section, considerando economias em desenvolvimento e desenvolvidas, dentro de um modelo de determinação de poupança que incorpora um índice de satisfação do direito de propriedade (PROP) como uma das variáveis explicativas. A principal conclusão, empírica, reforça a recomendação normativa segundo a qual direitos de propriedade bem definidos e garantidos pelo Estado são fundamentais para assegurar a estabilidade institucional necessária para fomentar a formação de poupança na economia.