Detta arbete uppstod från ett samarbetsprojekt mellan Högskolan i Gävle, Radarbolaget och Gävle Energi. Arbetet har syftet att för Gävle Energis kraftvärmeverk Johannes skapa PLC-program för skattning av momentana värden på effekt och utsläpp, samt skapa ett HMI som återger de skattade värdena i diagram och har reglage för fukthaltsändring. PLC-programmet skrevs med ABB Compact Control Builder och baserades på matematiska Z-transformmodeller framtagna av handledaren Niclas Björsell. Modellerna ska omvandla insignalerna bränsleinmatning, primärfläkt, sekundärfläkt, tertiärfläkt och fukthalt till utsignalerna effekt och NOx-utsläpp. HMI:t konstruerades i programmet ABB Plant Explorer Workplace och kopplade signaler för fukthalt, effekt och NOx-utsläpp till reglage och trenddiagram. Reglaget och trenddiagrammen lades in i en s.k. Faceplate som ska kunna läggas in i operatörernas existerande processbild på kraftvärmeverket. De matematiska modellerna för signalerna från PLC:n blev lite konstiga och kommer troligtvis åtgärdas i projektets fortsatta arbete. Det fortsatta arbetet innefattar även att skapa överföringsfunktioner, PLC-program och diagram för skattning av CO-utsläpp och stoftutsläpp, att skatta av framtida värden för uteffekt och utsläpp, att skapa avancerade modellfunktioner (i.e. MPC-funktioner) för beräkning av rekommenderad fukthalt i bränslet med avseende på uteffekt, NOx-utsläpp, CO-utsläpp eller stoft-utsläpp, samt att eventuellt skapa styrsignaler till värmeverkets process.

På det kommunalägda energiföretaget Sala Heby Energi AB pågår arbetet med att konvertera styrningen av en värmepanna från relästyrning och analog övervakning till digital styrning med PLC. Inom ramarna för detta examensarbete studeras tre specifika delar av denna konvertering: en teoretisk studie med syfte att kartlägga fördelar och nackdelar med konverteringen, en undersökning huruvida det finns möjlighet att förbättra en-skilda styrfunktioner i samband med konverteringen och upprättande av ett principschema eller översiktsbild över värmepannan som ska fungera som underlag till dess implementering i kraftvärmeverkets SCADA-system. En fördel med relästyrningen är att den kan vara kostnadseffektiv för att klara enskilda enkla styruppgifter. Dock, överlag och i synnerhet för styrning av större mer komplexa processer talar det mesta till den digitala styrningens fördel. Detta i form av kostnadseffektivitet för större system, möjligheter till mer effektiv larmhantering och möjligheten till loggning av driftdata. Två enskilda funktioner studeras: reglering av värmepannans siktskärm i förhållande till ångdomstrycket och styrning för bränslehanteringen. För reglering av siktskärmens höjd jämförs två alter-nativ med hjälp av simuleringar i Simulink. Konventionell PID-reglering jämförs mot en egenkonstruerad fuzzy-regulator. Mycket på grund av en bristfälligt underbyggd modellering av processen går inte fuzzy-regulatorns eventuella fördelar mot PID-regulatorn att fastställa. Framtida studier av fuzzy-regulatorn skulle potentiellt kunna ändra på detta förhållande. Vidare diskuteras styrningen av funktioner i bränslehantering och då främst autentisering av chaufförer som ska bränslefylla. För att de ska få tillgång till bränslehanteringens funktioner när kraftvärmeverket är obemannat föreslås det en lösning med nyckelbrytare för att aktivera aktuella styrfunktioner. Slutligen tas en ny digital översiktsbild fram över systemet för värmepannan. Denna innehåller mindre uppdateringar och anpassningar jämfört med två översiktsbilder som finns uppritade på de gamla styrskåpen. / At the municipality-owned energy company Sala Heby Energi AB work is underway to convert the control of a heating-pan from relay control and analog monitoring to digital control with PLC. Within the framework of this degree project, three specific parts of this conversion are studied: a theoretical study aimed at mapping the pros and cons of the conversion, an examination of the possibility of improving individual control functions in conjunction with the conversion and the establishment of a schematic diagram or overview of the heat boiler that will serve as a basis for its implementation in the SCADA-system of the combined power and heating plant. An advantage of relay control is that it can be cost-effective to handle individual simple control tasks. However, overall and in particular for controlling major more complex processes the benefits of digital control is large. This in terms of cost-effectiveness for larger systems, possibilities for more efficient alarm management and the ability to log operational data. Two individual functions are studied: control of the heating pans damper in relation to the steam pressure and fuel management control. To adjust the height of the damper, two control options are compared using Simulink simulations. Conventional PID control is com-pared to a self-configured fuzzy controller. Much due to a poorly substantiated modelling of the process, the fuzzy regulator's possible benefits to the PID regulator can not be determined. Future studies of the fuzzy regulator could potentially change this circumstance. Furthermore, the control of functions for the fuel management are discussed, mainly authorship of drivers who will fill fuel to the fuel storage. In order for them to have access to the fuel management functions when the combined power and heating plant is unmanned, a key switch solution is proposed to activate the control functions. Finally, a new digital overview picture is produced for the system of the heating pan. This contains minor up-dates and adjustments compared to two overview images depicted on the old control cabinets.

A TPV-system consists of a hot surface emitting heat radiation on a solar cell with a narrow bandgap.  A unit consisting of a boiler and a TPV-system has been constructed for testing of the performance of TPV cells. The emitter is heated by a fuel consisting of RME-oil. The radiation is collected and concentrated through two reflecting cones formed like a Faberge-egg, with an edge-type optical filter between the cones. The Faberge-egg is treated with electro-polishing in order to obtain a high reflectance of radiation. The edge filter transmits radiation of short wavelengths towards the solar cells and reflects long wavelengths back to the emitter. This increase the temperature of the emitter to prevent the TPV-cells to be overheated. The construction made was working as expected and can be used for further experiments. The performance of the TPV-cells were however very poor because of a low emitter temperature. The main problem was to obtain a good heat transport from the flame to the emitter. It is required that the emitter temperature is considerably increased for justifying a continued work on TPV-systems in combination with boilers.

<p>The goal of this project was to evaluate three main proposals, by the Property Management Department (PMD) of St. Louis County, which the department hoped would reduce energy consumption at their Duluth Jail facility. This particular facility was opened in 1995 and houses approximately 170 inmates. Despite its relatively new construction, the building produces some of the highest utility bills of all of the County’s buildings.</p><p>The proposals put forth by the PMD were the following: to reduce natural gas consumption by using solar water heating for the domestic hot water; to reduce heating and cooling costs by enclosing a light well which is currently open to the sky with a transparent, insulated roof; and to utilize a white roof to reduce cooling demand during the summertime.</p><p>The solar water heating proposal was evaluated by determining the energy the solar system could provide annually and comparing these energy- and monetary savings to the cost of the system. Two solar options were evaluated; one system with 20 collectors and another with 50. Both systems also included condensing boilers to provide supplementary heating during times of low solar output. The annual savings of the 20- and 50 collector systems were 128 and 173 MWh, respectively. This led to a payback period of approximately 17 years for the 20 collector system and 16 years for the 50 collector system.</p><p>Enclosing the open light well, which is an open area inside the perimeter of the building which is designed to give rooms on the inside of the building natural daylight, was evaluated by performing an energy flow analysis comparing the existing condition with one in which a roof topped the well. This involved calculating the U-values of the walls before the skyroof and then using heating and cooling degree days to determine the heat flows through the walls. The enclosed light well was evaluated by performing an energy balance on the well to determine the temperature of the enclosed well. This temperature could then be used to calculate the heat flow through the enclosed light well’s walls. The difference in these heat flows between the two options was then converted to an economic cost to evaluate a payback period. Two grades of Kalwall-brand insulation were evaluated; the “Nanogel” grade and a mid-range grade. The Nanogel-enclosed light well reduced the heating demand by 16 MWh but increased the cooling load by 9 MWh, while the mid-grade enclosed well decreased the heating load by 11 MWh but increased the cooling load by 4 MWh. These added up to net annual savings of $650 for the Nanogel roof and $470 for the mid-grade skyroof. However, the investment costs were so high that the payback periods were between 450 and 550 years.</p><p>Two white roofing options were considered and corresponded to a newly installed roof and one that had weathered for 3 years, thereby reducing its reflectivity. These options were evaluated by determining the mean monthly roof temperatures throughout a typical year and calculating the heat flows through the roofs based on these temperatures. The temperatures were determined by performing a heat balance on the roofs’ surfaces and considering the solar radiation incident on the roofs. The heat flows with the existing black colored roof and the proposed white roofs were thencompared and converted into heating and cooling costs. The white roofs led to summertime air-conditioning savings but created more wintertime heat losses and therefore caused net annual energy cost increases of $560 and $240 for the new and weathered roofs, respectively.</p><p>The recommendations therefore were to implement the solar thermal system but not the other two proposals. Other areas which might benefit from additional investigations include lighting efficiency improvements, water use reductions, and replacement of the existing boilers with either more efficient natural gas units or wood-pellet/biomass boilers.</p>

The goal of this project was to evaluate three main proposals, by the Property Management Department (PMD) of St. Louis County, which the department hoped would reduce energy consumption at their Duluth Jail facility. This particular facility was opened in 1995 and houses approximately 170 inmates. Despite its relatively new construction, the building produces some of the highest utility bills of all of the County’s buildings. The proposals put forth by the PMD were the following: to reduce natural gas consumption by using solar water heating for the domestic hot water; to reduce heating and cooling costs by enclosing a light well which is currently open to the sky with a transparent, insulated roof; and to utilize a white roof to reduce cooling demand during the summertime. The solar water heating proposal was evaluated by determining the energy the solar system could provide annually and comparing these energy- and monetary savings to the cost of the system. Two solar options were evaluated; one system with 20 collectors and another with 50. Both systems also included condensing boilers to provide supplementary heating during times of low solar output. The annual savings of the 20- and 50 collector systems were 128 and 173 MWh, respectively. This led to a payback period of approximately 17 years for the 20 collector system and 16 years for the 50 collector system. Enclosing the open light well, which is an open area inside the perimeter of the building which is designed to give rooms on the inside of the building natural daylight, was evaluated by performing an energy flow analysis comparing the existing condition with one in which a roof topped the well. This involved calculating the U-values of the walls before the skyroof and then using heating and cooling degree days to determine the heat flows through the walls. The enclosed light well was evaluated by performing an energy balance on the well to determine the temperature of the enclosed well. This temperature could then be used to calculate the heat flow through the enclosed light well’s walls. The difference in these heat flows between the two options was then converted to an economic cost to evaluate a payback period. Two grades of Kalwall-brand insulation were evaluated; the “Nanogel” grade and a mid-range grade. The Nanogel-enclosed light well reduced the heating demand by 16 MWh but increased the cooling load by 9 MWh, while the mid-grade enclosed well decreased the heating load by 11 MWh but increased the cooling load by 4 MWh. These added up to net annual savings of $650 for the Nanogel roof and $470 for the mid-grade skyroof. However, the investment costs were so high that the payback periods were between 450 and 550 years. Two white roofing options were considered and corresponded to a newly installed roof and one that had weathered for 3 years, thereby reducing its reflectivity. These options were evaluated by determining the mean monthly roof temperatures throughout a typical year and calculating the heat flows through the roofs based on these temperatures. The temperatures were determined by performing a heat balance on the roofs’ surfaces and considering the solar radiation incident on the roofs. The heat flows with the existing black colored roof and the proposed white roofs were thencompared and converted into heating and cooling costs. The white roofs led to summertime air-conditioning savings but created more wintertime heat losses and therefore caused net annual energy cost increases of $560 and $240 for the new and weathered roofs, respectively. The recommendations therefore were to implement the solar thermal system but not the other two proposals. Other areas which might benefit from additional investigations include lighting efficiency improvements, water use reductions, and replacement of the existing boilers with either more efficient natural gas units or wood-pellet/biomass boilers.