Combined solar and pellet heating systems for single-family houses : How to achieve decreased electricity usage, increased system efficiency and increased solar gains

In Sweden, there are about 0.5 million single-family houses that are heated by electricity alone, and rising electricity costs force the conversion to other heating sources such as heat pumps and wood pellet heating systems. Pellet heating systems for single-family houses are currently a strongly growing market. Future lack of wood fuels is possible even in Sweden, and combining wood pellet heating with solar heating will help to save the bio-fuel resources. The objectives of this thesis are to investigate how the electrically heated single-family houses can be converted to pellet and solar heating systems, and how the annual efficiency and solar gains can be increased in such systems. The possible reduction of CO-emissions by combining pellet heating with solar heating has also been investigated. Systems with pellet stoves (both with and without a water jacket), pellet boilers and solar heating have been simulated. Different system concepts have been compared in order to investigate the most promising solutions. Modifications in system design and control strategies have been carried out in order to increase the system efficiency and the solar gains. Possibilities for increasing the solar gains have been limited to investigation of DHW-units for hot water production and the use of hot water for heating of dishwashers and washing machines via a heat exchanger instead of electricity (heat-fed appliances). Computer models of pellet stoves, boilers, DHW-units and heat-fed appliances have been developed and the parameters for the models have been identified from measurements on real components. The conformity between the models and the measurements has been checked. The systems with wood pellet stoves have been simulated in three different multi-zone buildings, simulated in detail with heat distribution through door openings between the zones. For the other simulations, either a single-zone house model or a load file has been used. Simulations were carried out for Stockholm, Sweden, but for the simulations with heat-fed machines also for Miami, USA. The foremost result of this thesis is the increased understanding of the dynamic operation of combined pellet and solar heating systems for single-family houses. The results show that electricity savings and annual system efficiency is strongly affected by the system design and the control strategy. Large reductions in pellet consumption are possible by combining pellet boilers with solar heating (a reduction larger than the solar gains if the system is properly designed). In addition, large reductions in carbon monoxide emissions are possible. To achieve these reductions it is required that the hot water production and the connection of the radiator circuit is moved to a well insulated, solar heated buffer store so that the boiler can be turned off during the periods when the solar collectors cover the heating demand. The amount of electricity replaced using systems with pellet stoves is very dependant on the house plan, the system design, if internal doors are open or closed and the comfort requirements. Proper system design and control strategies are crucial to obtain high electricity savings and high comfort with pellet stove systems. The investigated technologies for increasing the solar gains (DHW-units and heat-fed appliances) significantly increase the solar gains, but for the heat-fed appliances the market introduction is difficult due to the limited financial savings and the need for a new heat distribution system. The applications closest to market introduction could be for communal laundries and for use in sunny climates where the dominating part of the heat can be covered by solar heating. The DHW-unit is economical but competes with the internal finned-tube heat exchanger which is the totally dominating technology for hot water preparation in solar combisystems for single-family houses.

Elbesparing med pelletkaminer och solvärme i direktelvärmda småhus

The aim of this study was to investigate how electricallyheated houses can be converted to using wood pellet and solarheating. There are a large number of wood pellet stoves on themarket. Many stoves have a water jacket, which gives anopportunity to distribute the heat to domestic hot water and aradiator heating system. Three typical Swedish houses with electric resistanceheating have been studied. Fourteen different system conceptsusing wood pellet stoves and solar heating systems have beenevaluated. The systems and the houses have been simulated indetail using TRNSYS. The houses have been divided in up to 10different zones and heat transfer by air circulation throughdoorways and open doors have been simulated. The pellet stoveswere simulated using a recently developed TRNSYS component,which models the start- and stop phases, emissions and thedynamic behaviour of the stoves. The model also calculates theCO-emissions. Simulations were made with one stove without awater jacket and two stoves with different fractions of thegenerated heat distributed in the water circuit. Simulations show that the electricity savings using a pelletstove are greatly affected by the house plan, the systemchoice, if the internal doors are open or closed and thedesired level of comfort. Installing a stove with awater-jacket connected to a radiator system and a hot waterstorage has the advantage that heat can be transferred todomestic hot water and be distributed to other rooms. Suchsystems lead to greater electricity savings, especially inhouses having a traditional layout. It was found that not allrooms needed radiators and that it was more effective in mostcases t use a stove with a higher fraction of the heatdistributed by the water circuit. The economic investigation shows that installing a woodpellet stove without a water jacket gives the lowest totalenergy- and capital costs in the house with an open plan (fortoday's energy prices and the simulated comfort criteria). Inthe houses with a traditional layout a pellet stove givesslightly higher costs than the reference house having onlyelectrical resistance heating due to the fact that less heatingcan be replaced. The concepts including stoves with a waterjacket all give higher costs than the reference system, but theconcept closest to be economical is a system with a bufferstore, a stove with a high fraction of the heat distributed bythe water circuit, a new water radiator heating system and asolar collector. Losses from stoves can be divided into: flue gas lossesincluding leakage air flow when the stove is not in operation;losses during start and stop phases; and losses due to a highair factor. An increased efficiency of the stoves is importantboth from a private economical point of view, but also from theperspective that there can be a lack of bio fuel in the nearfuture also in Sweden. From this point of view it is alsoimportant to utilize as much solar heat as possible. Theutilization of solar heat is low in the simulated systems,depending on the lack of space for a large buffer store. The simulations have shown that the annual efficiency ismuch lower that the nominal efficiency at full power. Thesimulations have also shown that changing the control principlefor the stove can improve efficiency and reduce theCO-emissions. Today's most common control principle for stovesis the on/off control, which results in many starts and stopsand thereby high CO-emissions. A more advanced control varyingthe heating rate from maximum to minimum to keep a constantroom temperature reduces the number of starts and stops andthereby the emissions. Also the efficiency can be higher withsuch a control, and the room temperature will be kept at a moreconstant temperature providing a higher comfort.

Att bli, att vara och att ha varit - om ingångar i och utgångar ur Jehovas vittnen i Sverige

Summary To become, to be and to have been: about the  Jehovah’s Witnesses The Watchtower Bible and Tract Society, in the following text referred to as the Jehovah’s Witnesses or “the organisation”, is a worldwide Christian organisation with about 6.7 million members. The organisation has many times, without any success so far, proclaimed Armageddon when they expect Jehovah to return to Earth. They interpret the Bible in their own, often very literal way, and require their members to live according to these interpretations. Among the consequences of this, members are forbidden to vote, to do military service or to receive blood transfusions. Apart from attending the three weekly meetings, members are expected to be active in missionary work, known as “publishing”. If a member fails to do a certain number of hours’ publishing, he or she risks being deprived of active membership status Sweden in general is considered to be a society where the population is not very religious. The formerly state-governed Lutheran church has lost its influence and the vast majority of ordinary Swedes do not visit church on other occasions than weddings, funerals or christenings. Expressing one’s own religious values has become somewhat of a private matter where publicity is seldom appreciated, which is contrary to the practice of the Jehovah’s Witnesses. This is one of the reasons why the Jehovah’s Witnesses are commonly perceived by average Swedes as a “suspicious” religious organisation. The aim and methods of the study This dissertation seeks to describe and investigate the entering and leaving of a highly structured and hierarchical religious community, exemplified in this case by the Jehovah’s Witnesses. What are the thoughts and aspirations of someone who is considering becoming a Jehovah’s Witness? What are the priorities and what experiences seem important when a person is going through such a process? And when this person has finally reached his or her goal of becoming a member, is it the same motivation that makes him or her stay in the organisation for longer periods of time, possibly for the rest of their lives, or does it change during the process of entering, or does this motivation change its character during the transition from entering to being a regular member? Why do some of the members change their attitude to the Jehovah’s Witnesses from rejoicing to bitterness? And how does this process of exit manifest itself? In what way is it different from the process of entry? The respondents in this study were chosen from both active members of the Jehovah’s Witnesses in Sweden and those who have left the organisation for personal reasons. Repeated interviews with ten active members of the organisation have been conducted in the course of the study and compared to equal numbers of former members. The interviews have been semi-structured to deal with questions of how a person has come into contact with the organisation; how they retrospectively experienced the process of entry; the reasons for becoming a member. Questions have also been asked about life in the organisation. The group of “exiters” have also been asked about the experience of leaving, why they wanted to leave, and how this process was started and carried out. In addition to this I have analysed a four-year diary describing the time inside and the process of leaving the organisation. This has given me an extra psychological insight into the inner experience of someone who has gone through the whole process. The analysis has been done by categorising the content of the transcribed interviews. An attempt to outline a model of an entry and exit process has been made, based on ideas and interpretations presented in the interviews. The analysis of the diary has involved thorough reading, resulting in a division of it into four different parts, where each part has been given a certain key-word, signifying the author’s emotional state when writing it. A great deal of the information about the Jehovah’s Witnesses has been collected through discussion boards on the Internet, informal talks with members and ex-members, interviews with representatives of the organisations during visits to its different offices (Bethels), such as St. Petersburg, Russia, and Brooklyn, New York, USA. The context Each organisation evolves in its own context with its own norms, roles and stories that would not survive outside it. With this as a starting point, there is a chapter dedicated to the description of the organisation’s history, structure and activities. It has been stated that the organisation’s treatment of its critical members and the strategies for recruiting new members have evolved over the years of its history. At the beginning there was an openness allowing members to be critical. As the structure of the organisation has become more rigid and formalised, the treatment of internal critics has become much less tolerated and exclusion has become a frequent option. As a rule many new members have been attracted to the organisation when (1) the day of Armageddon has been pronounced to be approaching; (2) the members of the organisation have been persecuted or threatened with persecution; and (3) the organisation has discovered a “new market”. The processes for entering and exiting How the entering processes manifest themselves depends on whether the person has been brought up in the organisation or not. A person converting as an adult has to pass six phases before being considered a Jehovah’s Witness by the organisation. These are:  Contact with the Jehovah’s Witnesses, Studying the bible with members of the organisation, Questioning, Accepting, Being active as publisher (spreading the belief), Being baptised.  For a person brought up in the organisation, the process to full membership is much shorter:   Upbringing in the organisation, Taking a stand on the belief, Being baptised. The exit process contains of seven phases:   Different levels of doubts, Testing of doubts, Turning points, Different kinds of decisions, Different steps in executing the decisions, Floating, a period of emotional and cognitive consideration of membership and its experiences, Realtive neutrality.   The process in and the process out are both slow and are accompanied with anguish and doubts. When a person is going through the process in or out of the organisation he or she experiences criticism. This is when people around the adept question the decision to continue in the process. The result of the criticism depends on where in the process the person is. If he or she is at the beginning of the process, the criticism will probably make the person insecure and the process will slow down or stop. If the criticism is pronounced in a later phase, the process will probably speed up. The norms of the organisation affect the behaviour of the members. There are techniques for inclusion that both bind members to the organisation and shield them off from the surrounding society. Examples of techniques for inclusion are the “work situation” and “closed doors”. The work situation signifies that members who do as the organisation recommends – doing simple work – often end up in the same branch of industry as many other Jehovah’s Witnesses. This often means that the person has other witnesses as workmates. If the person is unemployed or moves to another town it is easy to find a new job through connections in the organisation. Doubts and exclusions can lead to problems since they entail a risk of losing one’s job. This can also result in problems getting a new job. Jehovah’s Witnesses are not supposed to talk to excluded members, which of course mean difficulties working together. “Closed doors” means that members who do as the organisation recommends – not pursuing higher education, not engaging in civil society, working with a manual or in other way simple job, putting much time into the organisation – will, after a long life in the organisation, have problems starting a new life outside the Jehovah’s Witnesses. The language used in the organisation shows the community among the members, thus the language is one of the most important symbols. A special way of thinking is created through the language. It binds members to the organisation and sometimes it can work as a way to get back into the normative world of the organisation. Randall Collins’s (1990, 2004) thoughts about “emotional energy” have enabled an understanding of the solidarity and unity in the organisation. This also gives an understanding of the way the members treat doubting and critical members. The members who want to exit have to open up the binding/screening off. A possible way to do that is through language, to become aware of the effect the language might have. Another way is to search for emotional energy in another situation. During the exit process, shame might be of some importance. When members become aware of the shame they feel, because they perceive they are “acting a belief”, the exit process might accelerate.

La cortesía verbal : Un estudio contrastivo entre los saludos y peticiones en los idiomas sueco y español. Författare: Daisy

The purpose of this study is to examine the differences and similarities regarding verbal politeness in greetings and requests in Swedish and the Chilean variety of Spanish. A survey with 12 questions, both open-ended and closed-ended, has been distributed to 20 native speakers of the two languages. Thus, the questions have been analyzed both quantitatively and qualitatively. The results show that the perception that the Swedes and the Chileans have about verbal politeness is similar, since the speakers of both languages see it as a way to show respect towards others. The study also shows that Swedes and Chileans share a similar view upon politeness, i.e. as a social norm that facilitates social interaction between people.

La cortesía verbal : Un estudio contrastivo entre los saludos y peticiones en los idiomas sueco y español

The purpose of this study is to examine the differences and similarities regarding verbal politeness in greetings and requests in Swedish and the Chilean variety of Spanish. A survey with 12 questions, both open-ended and closed-ended, has been distributed to 20 native speakers of the two languages. Thus, the questions have been analyzed both quantitatively and qualitatively. The results show that the perception that the Swedes and the Chileans have about verbal politeness is similar, since the speakers of both languages see it as a way to show respect towards others. The study also shows that Swedes and Chileans share a similar view upon politeness, i.e. as a social norm that facilitates social interaction between people.