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95-459: The Avedøre Power Station was designed by the architects Claus Bjarrum and Jørgen Hauxner. Having been built in 1990 this is the oldest unit. Coal was the primary fuel used in this unit, but oil can also be used. By utilising the excess heat from the power production for district heating , Avedøre unit 1 attained an energy conversion efficiency of up to 91%. This made Avedøre 1 one of the world's most efficient coal-fired power plants. As of 2015, it

190-418: A socialist economy (such as in the former Eastern Bloc ) which lacked heat metering and means to adjust the heat delivery to each apartment. This led to great inefficiencies – users had to simply open windows when too hot – wasting energy and minimising the numbers of connectable customers. District heating systems can vary in size. Some systems cover entire cities such as Stockholm or Flensburg , using

285-513: A consistent heat output day to day and between summer and winter. Good examples are in Vojens at 50 MW, Dronninglund at 27 MW and Marstal at 13 MW in Denmark. These systems have been incrementally expanded to supply 10% to 40% of their villages' annual space heating needs. The solar-thermal panels are ground-mounted in fields. The heat storage is pit storage, borehole cluster and

380-712: A hot water resource outside of Boise, Idaho. In 1892, after routing the water to homes and businesses in the area via a wooden pipeline, the first geothermal district heating system was created. As of a 2007 study, there were 22 geothermal district heating systems (GDHS) in the United States. As of 2010, two of those systems have shut down. The table below describes the 20 GDHS currently operational in America. Use of solar heat for district heating has been increasing in Denmark and Germany in recent years. The systems usually include inter seasonal thermal energy storage for

475-522: A low-temperature internal heat distribution system can install an efficient heat pump delivering heat output at 45 °C. An older building with a higher-temperature internal distribution system e.g. using radiators will require a high-temperature heat pump to deliver heat output. A larger example of a fifth generation heating and cooling grid is Mijnwater in Heerlen, the Netherlands. In this case

570-474: A network of large 1000 mm diameter primary pipes linked to secondary pipes – e.g. 200 mm diameter, which in turn link to tertiary pipes that might be of 25 mm diameter which might connect to 10 to 50 houses. Annapolis Annapolis ( / ə ˈ n æ p əl ɪ s / ə- NAP -əl-iss ) is the capital of the U.S. state of Maryland . It is the county seat of Anne Arundel County and its only incorporated city. Situated on

665-499: A steel heat service pipe, an insulating layer ( polyurethane foam) and a polyethylene (PE) casing, which are bonded by the insulating material. While polyurethane has outstanding mechanical and thermal properties, the high toxicity of the diisocyanates required for its manufacturing has caused a restriction on their use. This has triggered research on alternative insulating foam fitting the application, which include polyethylene terephthalate (PET) and polybutylene (PB-1). Within

760-750: A suburb of the country's capital between 1964 and 1974. The Beznau Nuclear Power Plant in Switzerland has been generating electricity since 1969 and supplying district heating since 1984. The Haiyang Nuclear Power Plant in China started operating in 2018 and started supplying small scale heat to the Haiyang city area in 2020. By November 2022, the plant used 345 MW-thermal effect to heat 200,000 homes, replacing 12 coal heating plants. Recent years have seen renewed interest in small modular reactors (SMRs) and their potential to supply district heating. Speaking on

855-531: A super critical boiler , built by the Danish company Burmeister & Wain Energy. The Avedøre unit 2 has a production capacity of 585 MW of electricity and 570 MW of heat and is the most efficient of the two units. The Avedøre unit 2 also consists of multiple sub-units. The main sub-unit, the 80 metres (260 ft) super critical boiler is linked to a steam turbine and an electrical generator . One of

950-572: Is "the best single portrait of men and manners, of rural and urban life, of the wide range of society and scenery in colonial America." Annapolis became the temporary capital of the United States after the signing of the Treaty of Paris in 1783. Congress was in session in the state house from November 26, 1783, to August 19, 1784, and it was in Annapolis on December 23, 1783, that General Washington resigned his commission as commander-in-chief of

1045-423: Is being converted from coal to wood pellets at a price of DKK 740 million. It will burn 1.2 million tonnes of wood pellets per year, reducing CO 2 emissions with about a million tonnes. Having been built in 2001 this is the newest and most efficient unit at Avedøre Power Station. It is able to burn a wide variety of fuels like natural gas , heavy fuel oil , straw and wood pellets in the same burners. It has

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1140-452: Is expected to be able to cover approximately 20% of the district heating demand in Aarhus. United States Direct use geothermal district heating systems, which tap geothermal reservoirs and distribute the hot water to multiple buildings for a variety of uses, are uncommon in the United States, but have existed in America for over a century. In 1890, the first wells were drilled to access

1235-593: Is extracted from seawater (from 60-foot (18 m) depth) that is 8 to 9 °C all year round, giving an average coefficient of performance (COP) of about 3.15. In the process the seawater is chilled to 4 °C; however, this resource is not used. In a district system where the chilled water could be used for air conditioning, the effective COP would be considerably higher. In the future, industrial heat pumps will be further de-carbonised by using, on one side, excess renewable electrical energy (otherwise spilled due to meeting of grid demand) from wind, solar, etc. and, on

1330-485: Is generally regarded as the first real district heating system. It used geothermal energy to provide heat for about 30 houses and started operation in the 14th century. The U.S. Naval Academy in Annapolis began steam district heating service in 1853. MIT began coal -fired steam district heating in 1916 when it moved to Cambridge, Massachusetts . Although these and numerous other systems have operated over

1425-419: Is generally reported to be relatively low, such as 1% (compared to 25% for supermarket cooling systems). A 30-megawatt heatpump could therefore leak (annually) around 75 kg of R134a or other working fluid. However, recent technical advances allow the use of natural heat pump refrigerants that have very low global warming potential (GWP). CO 2 refrigerant (R744, GWP=1) or ammonia (R717, GWP=0) also have

1520-706: Is land and 0.92 square miles (2.38 km ) is water. Annapolis lies within the humid subtropical climate zone ( Köppen Cfa ), with hot, humid summers, cool winters, and generous precipitation year-round. Low elevation and proximity to the Chesapeake Bay give the area more moderate spring and summertime temperatures and slightly less extreme winter lows than locations further inland, such as Washington, D.C. See or edit raw graph data . In November 2020, NASA reported that Annapolis had 18 days of high-tide (non-storm-related) flooding from May 2019 to April 2020, an increase over 2018's 12 days, and higher than

1615-498: Is much wind energy or providing electricity from biomass plants when back-up power is needed. Therefore, large scale heat pumps are regarded as a key technology for smart energy systems with high shares of renewable energy up to 100% and advanced fourth generation district heating systems. A fifth generation district heating and cooling network (5GDHC), also called cold district heating , distributes heat at near ambient ground temperature: this in principle minimizes heat losses to

1710-465: Is often obtained from a cogeneration plant burning fossil fuels or biomass , but heat-only boiler stations , geothermal heating , heat pumps and central solar heating are also used, as well as heat waste from factories and nuclear power electricity generation. District heating plants can provide higher efficiencies and better pollution control than localized boilers. According to some research, district heating with combined heat and power (CHPDH)

1805-566: Is the Drammen Fjernvarme District Heating project in Norway which produces 14 MW from water at just 8 °C, industrial heat pumps are demonstrated heat sources for district heating networks. Among the ways that industrial heat pumps can be used are: Concerns have existed about the use of hydrofluorocarbons as the working fluid (refrigerant) for large heat pumps. Whilst leakage is not usually measured, it

1900-447: Is the burning of hydrocarbons . As the supply of renewable fuels is insufficient, the fossil fuels coal and gas are massively used for district heating. This burning of fossil hydrocarbons usually contributes to climate change , as the use of systems to capture and store the CO 2 instead of releasing it into the atmosphere is rare. In the case of a cogeneration plant, the heat output

1995-586: Is the cheapest method of cutting carbon emissions, and has one of the lowest carbon footprints of all fossil generation plants. District heating is ranked number 27 in Project Drawdown 's 100 solutions to global warming . District heating traces its roots to the hot water-heated baths and greenhouses of the ancient Roman Empire . A hot water distribution system in Chaudes-Aigues in France

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2090-406: Is typically sized to meet half of the peak winter heat load, but over the year will provide 90% of the heat supplied. Much of the heat produced in summer will generally be wasted. The boiler capacity will be able to meet the entire heat demand unaided and can cover for breakdowns in the cogeneration plant. It is not economic to size the cogeneration plant alone to be able to meet the full heat load. In

2185-796: The Chesapeake Bay at the mouth of the Severn River , 25 miles (40 km) south of Baltimore and about 30 miles (50 km) east of Washington, D.C. , Annapolis forms part of the Baltimore–Washington metropolitan area . The 2020 census recorded its population as 40,812, an increase of 6.3% since 2010. This city served as the seat of the Confederation Congress , formerly the Second Continental Congress , and temporary national capital of

2280-471: The Energy Impact Center 's (EIC) podcast, Titans of Nuclear , principal engineer at GE Hitachi Nuclear Energy Christer Dahlgren noted that district heating could be the impetus for the construction of new nuclear power plants in the future. EIC's own open-source SMR blueprint design, OPEN100 , could be incorporated into a district heating system. History Geothermal district heating

2375-632: The English Commonwealth period. In 1660, he was replaced by Phillip Calvert (1626–1682) as fifth/sixth Governor of Maryland , after the restoration of Charles II (1630–1685) as King in England . In 1694, soon after the overthrow of the Catholic government of second Royal Governor Thomas Lawrence (1645–1714, in office for a few months in 1693), the third Royal Governor Francis Nicholson (1655-1727/28, in office: 1694–1698), moved

2470-629: The New York City steam system , that is around 2.5 GW. Germany has the largest amount of CHP in Europe. A simple thermal power station can be 20–35% efficient, whereas a more advanced facility with the ability to recover waste heat can reach total energy efficiency of nearly 80%. Some may approach 100% based on the lower heating value by condensing the flue gas as well. The heat produced by nuclear chain reactions can be injected into district heating networks. This does not contaminate

2565-581: The Province of Maryland named "Providence" was founded on the north shore of the Severn River on the middle Western Shore of the Chesapeake Bay in 1649 by Puritan exiles from the Province/Dominion of Virginia led by the third Proprietary Governor of Maryland , William Stone (1603–1660). The settlers later moved to a better-protected harbor on the Severn's southern shore. The settlement on

2660-557: The Severn River . Students that attend the Naval Academy are enrolled for four years with a following five year commitment to serving on active duty in the Marine Corps or Navy. Students hold the naval rank of Midshipman , and on average about 4,500 are enrolled. St. John's College is a non-sectarian private college that was once supported by the state. It was opened in 1789 as the successor of King William's School, which

2755-554: The Treaty of Paris was ratified there on January 14, 1784, so Annapolis became the first peacetime capital of the U.S. It was in the Maryland State House that George Washington famously resigned his commission before the Continental Congress on December 23, 1783. The United States Naval Academy was founded in 1845 on the site of Fort Severn , and now occupies an area of land reclaimed from

2850-421: The thermal efficiency of cogeneration plants is significantly lower if the cooling medium is high-temperature steam, reducing electric power generation. Heat transfer oils are generally not used for district heating, although they have higher heat capacities than water, as they are expensive and have environmental issues. At customer level the heat network is usually connected to the central heating system of

2945-491: The 1930s and was built until the 1970s. It burned coal and oil, and the energy was transmitted through pressurized hot water as the heat carrier. The systems usually had supply temperatures above 100 °C, and used water pipes in concrete ducts, mostly assembled on site, and heavy equipment. A main reason for these systems was the primary energy savings, which arose from using combined heat and power plants. While also used in other countries, typical systems of this generation were

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3040-426: The 1995-2005 average of 2 days annually. The increase is attributed to sea level rise caused by climate change . Resultant flood damages caused local businesses to lose as much as $ 172,000 a year. On Naval Academy grounds, seawater came out of storm drains, with McNair Road and Ramsay Road flooding 20 times in 2020 and more than 40 times each in 2018 and 2019. Adaptation approaches such as sea walls and building up

3135-572: The Colonial Players theater in 1981. Based on the play by Charles Dickens , the 90-minute production by the Colonial Players is an original musical adaptation, with play and lyrics by Richard Wade and music by Dick Gessner. Colonial Players, Inc. is a nonprofit organization founded in 1949. Its first production, The Male Animal , was performed in 1949 at the Annapolis Recreation Center on Compromise Street. In 1955,

3230-561: The Continental Army. For the 1783 Congress, the Governor of Maryland commissioned John Shaw , a local cabinetmaker, to create an American flag . Shaw's flag is slightly different from other designs of the time: the blue field extends over the entire height of the hoist. Shaw developed two versions of the flag: one which started with a red stripe and another that started with a white one. In 1786, delegates from all states of

3325-709: The Korean and Vietnam wars. It was at Annapolis in July 1940 that Grand Duchess Charlotte of Luxembourg arrived in exile during World War II. In the summer of 1984, the Navy Marine Corps Memorial Stadium in Annapolis hosted soccer games as part of the XXIII Olympiad . During September 18–19, 2003, Hurricane Isabel created the largest storm surge known in Annapolis's history, cresting at 7.58 feet (2.31 m). Much of downtown Annapolis

3420-681: The Soviet-style district heating systems that were built after WW2 in several countries in Eastern Europe. In the 1970s the third generation was developed and was subsequently used in most of the following systems all over the world. This generation is also called the "Scandinavian district heating technology", because many of the district heating component manufacturers are based in Scandinavia. The third generation uses prefabricated, pre-insulated pipes, which are directly buried into

3515-621: The Union were invited to meet in Annapolis to consider measures for the better regulation of commerce. Delegates from only five states—New York, Pennsylvania, Virginia, New Jersey, and Delaware—actually attended the September 1786 gathering, known afterward as the Annapolis Convention . Without proceeding to the business for which they had met, the delegates passed a resolution calling for another convention to meet at Philadelphia in

3610-616: The United States in 1783–1784. At that time, General George Washington came before the body convened in the new Maryland State House and resigned his commission as commander of the Continental Army . A month later, the Congress ratified the Treaty of Paris of 1783 , ending the American Revolutionary War , with Great Britain recognizing the independence of the United States. The city and state capitol

3705-552: The academy's English curriculum. The King William Players, a student theater group at St. John's College , holds two performances each semester in the college's Francis Scott Key Auditorium. Admission is usually free and open to the public. The Banneker-Douglass Museum , located in the historic Mount Moriah Church at 87 Franklin Street, documents the history of African Americans in Maryland. Since its opening on February 24, 1984,

3800-430: The ambient circuit is preferably controlled by heat exchange with an aquifer or another low temperature water source to remain within a temperature range from 10 °C to 25 °C. While network piping for ambient ground temperature networks is less expensive to install per pipe diameter than in earlier generations, as it does not need the same degree of insulation for the piping circuits, it has to be kept in mind that

3895-454: The benefit, depending on operating conditions, of resulting in higher heat pump efficiency than conventional refrigerants. An example is a 14 MW(thermal) district heating network in Drammen , Norway, which is supplied by seawater-source heatpumps that use R717 refrigerant, and has been operating since 2011. 90 °C water is delivered to the district loop (and returns at 65 °C). Heat

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3990-435: The benefits of biomass. As a by-product, high quality plaster is made when cleaning the flue gas . Avedøre Holme Offshore Wind Farm District heating District heating (also known as heat networks ) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating and water heating . The heat

4085-482: The capital of the royal colony, the Province of Maryland , to Anne Arundel's Towne and renamed the town "Annapolis" after Princess Anne of Denmark and Norway , soon to become Queen Anne of Great Britain (1665–1714, reigned 1702–1714). Annapolis was incorporated as a city in 1708. Colonel John Seymour, the Governor of Maryland from 1704 to 1709, wrote Queen Anne on March 16, 1709, with qualifications for municipal officials and provisions for fairs and market days for

4180-522: The census of 2010, there were 38,394 people, 16,136 households, and 8,776 families residing in the city. The population density was 5,347.4 inhabitants per square mile (2,064.6/km ). There were 17,845 housing units at an average density of 2,485.4 units per square mile (959.6 units/km ). The racial makeup of the city was 60.1% White , 26.0% African American , 0.3% Native American , 2.1% Asian , 9.0% from other races , and 2.6% from two or more races. Hispanic or Latino people of any race were 16.8% of

4275-493: The centuries, the first commercially successful district heating system was launched in Lockport , New York , in 1877 by American hydraulic engineer Birdsill Holly , considered the founder of modern district heating. Generally, all modern district heating systems are demand driven, meaning that the heat supplier reacts to the demand from the consumers and ensures that there is sufficient temperature and water pressure to deliver

4370-568: The city celebrated the 300th anniversary of its 1708 Royal Charter, which established democratic self-governance. The many cultural events of this celebration were organized by Annapolis Charter 300. Annapolis was home of the Anne Arundel County Battle of the Bands, which was held at Maryland Hall from 1999 to 2015. The event was a competition between musical groups from each high school in the county; it raised over $ 100,000 for

4465-563: The city is still referred to as Parole . The soldiers who did not survive were buried in the Annapolis National Cemetery . In 1900, Annapolis had a population of 8,585. On December 21, 1906, Henry Davis was lynched in the city. He was suspected of assaulting a local woman. Nobody was ever tried for the crime. During World War II , shipyards in Annapolis built a number of PT Boats, and military vessels such as minesweepers and patrol boats were built in Annapolis during

4560-430: The city was $ 49,243, and the median income for a family was $ 56,984 (these figures had risen to $ 70,140 and $ 84,573 respectively, according to a 2007 estimate ). Males had a median income of $ 39,548 versus $ 30,741 for females. The per capita income for the city was $ 27,180. About 9.5% of families and 12.7% of the population were living in poverty, of which 20.8% were under age 18 and 10.4% were age 65 or over. According to

4655-416: The city's 2018 Comprehensive Annual Financial Report, the top employers in the city, excluding state and local government, are: Annapolis has a thriving community theater scene which includes two venues in the historic district. On East Street, Colonial Players produces approximately six shows a year in its 180-seat theater. A Christmas Carol has been a seasonal tradition in Annapolis since it opened at

4750-417: The city. The population density was 5,326.0 inhabitants per square mile (2,056.4/km ). There were 16,165 housing units at an average density of 2,402.3 units per square mile (927.5 units/km ). The racial makeup of the city was 62.66% White , 31.44% Black or African American , 0.17% Native American , 1.81% Asian , 0.03% Pacific Islander , 2.22% from other races, and 1.67% from two or more races. 8.42% of

4845-549: The combustion of fossil hydrocarbons. However, only a small minority of the nuclear reactors currently in operation around the world are connected to a district heating network. These reactors are in Bulgaria, China, Hungary, Romania, Russia, Slovakia, Slovenia, Switzerland and Ukraine. The Ågesta Nuclear Power Plant in Sweden was an early example of nuclear cogeneration, providing small quantities of both heat and electricity to

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4940-558: The commerce was considerable, but it declined rapidly after Baltimore, with its deeper harbor, was made a port of entry in 1780. Water trades such as oyster-packing, boatbuilding and sailmaking became the city's chief industries. Annapolis is home to a large number of recreational boats that have largely replaced the seafood industry in the city. Dr. Alexander Hamilton (1712–1756), a Scottish-born doctor and writer, lived and worked in Annapolis. Leo Lemay says his 1744 travel diary Gentleman's Progress: The Itinerarium of Dr. Alexander Hamilton

5035-467: The county's high school music programs during its 17-year run. On June 28, 2018, at the Capital Gazette , a gunman opened fire, killing five journalists and injuring two more. An EF-2 tornado struck the western edge of the city on September 1, 2021, during the remnants of Hurricane Ida . Homes, businesses, and restaurants had significant damage near Maryland Route 450 , where EF-2 damage

5130-471: The demanded heat to the users. The five generations have defining features that sets them apart from the prior generations. The feature of each generation can be used to give an indication of the development status of an existing district heating system. The first generation was a steam-based system fueled by coal and was first introduced in the US in the 1880s and became popular in some European countries, too. It

5225-670: The distinguishing feature is a unique access to an abandoned water-filled coal mine within the city boundary that provides a stable heat source for the system. A fifth generation network ("Balanced Energy Network", BEN) was installed in 2016 at two large buildings of the London South Bank University as a research and development project. District heating networks exploit various energy sources, sometimes indirectly through multipurpose infrastructure such as combined heat and power plants (CHP, also called co-generation). The most used energy source for district heating

5320-966: The district heating by providing high flexibility to the electricity system. According to the review by Lund et al. those systems have to have the following abilities: Compared to the previous generations the temperature levels have been reduced to increase the energy efficiency of the system, with supply side temperatures of 70 °C and lower. Potential heat sources are waste heat from industry, CHP plants burning waste, biomass power plants , geothermal and solar thermal energy (central solar heating), large scale heat pumps , waste heat from cooling purposes and data centers and other sustainable energy sources. With those energy sources and large scale thermal energy storage , including seasonal thermal energy storage , fourth generation district heating systems are expected to provide flexibility for balancing wind and solar power generation, for example by using heat pumps to integrate surplus electric power as heat when there

5415-497: The district pipes with radioactive elements, as the heat is transferred to the network through heat exchangers . It is not technically necessary for the nuclear reactor to be very close to the district heating network, as heat can be transported over significant distances (exceeding 200 km) with affordable losses, using insulated pipes . Since nuclear reactors do not significantly contribute to either air pollution or global warming , they can be an advantageous alternative to

5510-484: The dwellings via heat exchangers (heat substations): the working fluids of both networks (generally water or steam) do not mix. However, direct connection is used in the Odense system. Typical annual loss of thermal energy through distribution is around 10%, as seen in Norway's district heating network. The amount of heat provided to customers is often recorded with a heat meter to encourage conservation and maximize

5605-522: The electrical efficiency decreases, as the heat exchange is carried out at a higher temperature. If the export of heat energy to district heating is taken into account the energy conversion efficiency reaches 94-96%, making it one of the world's most efficient combined heat and power (CHP) stations. In preparation for conversion to 100% biomass in 2027, the plant has received a 360 tonne crane capable of transferring 800 tonnes of wood pellets per hour from ship to shore, although some environmentalists question

5700-734: The electrical production having much higher rates of return than heat production, whilst storing the excess heat production. It also allows solar heat to be collected in summer and redistributed off season in very large but relatively low-cost in-ground insulated reservoirs or borehole systems. The expected heat loss at the 203,000m³ insulated pond in Vojens is about 8%. With European countries such as Germany and Denmark moving to very high levels (80% and 100% respectively by 2050) of renewable energy for all energy uses there will be increasing periods of excess production of renewable electrical energy. Heat pumps can take advantage of this surplus of cheap electricity to store heat for later use. Such coupling of

5795-540: The electricity sector with the heating sector ( Power-to-X ) is regarded as a key factor for energy systems with high shares of renewable energy. After generation, the heat is distributed to the customer via a network of insulated pipes. District heating systems consist of feed and return lines. Usually the pipes are installed underground but there are also systems with overground pipes. The DH system's start-up and shut downs, as well as fluctuations on heat demand and ambient temperature, induce thermal and mechanical cycling on

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5890-473: The energy mix. For example, Paris has been using geothermal heating from a 55–70 °C source 1–2 km below the surface for domestic heating since the 1970s. Currently, the fourth generation is being developed, with the transition to fourth generation already in process in Denmark . The fourth generation is designed to combat climate change and integrate high shares of variable renewable energy into

5985-519: The following spring at the head of a Cavalier royalist force, loyal to the uncrowned King of England . On March 25, 1655, in what became known as the Battle of the Severn (the first colonial naval battle in North America ), Stone was defeated, taken prisoner, and replaced by Lt. Gen. Josias Fendall (1628–1687) as fifth Proprietary Governor . Fendall governed Maryland during the latter half of

6080-669: The following year to amend the Articles of Confederation . The resulting Philadelphia Convention drafted and approved the Constitution of the United States , which remains in force. On April 24, 1861, the midshipmen of the Naval Academy relocated their base in Annapolis and were temporarily housed in Newport, Rhode Island , until October 1865. In 1861, the first of three camps that were built for holding paroled soldiers

6175-707: The former location of the Shaw Blacksmith Shop, in 1967, and became owner of the property in 1990. The Naval Academy Masqueraders, a theater group at the United States Naval Academy, produces one "main-stage show" each fall and student-directed one-act plays in the spring. Founded in 1847, the Masqueraders is the oldest extracurricular activity at the Naval Academy. Its shows, performed in Mahan Hall, are selected to support

6270-421: The ground and operates with lower temperatures, usually below 100 °C. A primary motivation for building these systems was security of supply by improving the energy efficiency after the two oil crises led to disruption of the oil supply. Therefore, those systems usually used coal, biomass and waste as energy sources, in preference to oil. In some systems, geothermal energy and solar energy are also used in

6365-450: The ground and reduces the need for extensive insulation. Each building on the network uses a heat pump in its own plant room to extract heat from the ambient circuit when it needs heat, and uses the same heat pump in reverse to reject heat when it needs cooling. In periods of simultaneous cooling and heating demands this allows waste heat from cooling to be used in heat pumps at those buildings which need heating. The overall temperature within

6460-411: The height of roadways and athletic fields are predicted to last only a few decades. As of the census of 2020, there were 40,812 people. The racial makeup of the city was 49.4% Non-Hispanic White , 21.7% African American , 0.7% Native American , 2.5% Asian , 14.5% from other races , and 8.1% from two or more races. Hispanic or Latino residents of any race made up 22.9% of the population. As of

6555-466: The individualization of the heat generation. This critical system has a significant impact when comparing the efficiencies between the different generations, as the individualization of the heat generation moves the comparison from being a simple distribution system efficiency comparison to a supply system efficiency comparison, where both the heat generation efficiency as well as the distribution system efficiency needs to be included. A modern building with

6650-430: The lower temperature difference of the pipe network leads to significantly larger pipe diameters than in prior generations. Due to the requirement of each connected building in the fifth generation district heating and cooling systems to have their own heat pump the system can be used both as a heat source or a heat sink for the heat pump, depending on if it is operated in a heating and cooling mode. As with prior generations

6745-467: The museum has provided educational programs, rotating exhibits, and a research facility. Admission is free. Preble Hall , named for Edward Preble , houses the U.S. Naval Academy Museum, founded in 1845. Its Beverley R. Robinson Collection contains 6,000 prints depicting European and American naval history from 1514 through World War II. It is also home to one of the world's best ship model collections, donated by Henry Huttleston Rogers . Rogers's donation

6840-575: The national capital. In land area Annapolis (proper) is also the smallest of the United States capital cities . The city is a part of the Atlantic Coastal Plain, and is relatively flat, with the highest point being only 50 feet (15 m) above sea level. According to the United States Census Bureau , the city has a total area of 8.10 square miles (20.98 km ), of which 7.18 square miles (18.60 km )

6935-431: The number of customers which can be served, but such meters are expensive. Due to the expense of heat metering, an alternative approach is simply to meter the water – water meters are much cheaper than heat meters, and have the advantage of encouraging consumers to extract as much heat as possible, leading to a very low return temperature, which increases the efficiency of power generation. Many systems were installed under

7030-543: The organization moved to its venue in a former automotive repair shop on East Street. During the warmer months, Annapolis Summer Garden Theatre presents three shows on its outdoor stage, which is visible from the City Dock. A nonprofit organization, Annapolis Summer Garden Theatre has been providing "theatre under the stars" since 1966, when it performed You Can't Take It with You and Brigadoon at Carvel Hall Hotel. It began leasing its site at 143 Compromise Street,

7125-399: The other side, by making more of renewable heat sources (lake and ocean heat, geothermal, etc.). Furthermore, higher efficiency can be expected through operation on the high voltage network. Increasingly large heat stores are being used with district heating networks to maximise efficiency and financial returns. This allows cogeneration units to be run at times of maximum electrical tariff,

7220-414: The pipe network is an infrastructure that in principle provides an open access for various low temperature heat sources, such as ambient heat, ambient water from rivers, lakes, sea, or lagoons, and waste heat from industrial or commercial sources. Based on the above description it is clear that there is a fundamental difference between the 5GDHC and the prior generations of district heating, particularly in

7315-517: The pipes due to the thermal expansion. The axial expansion of the pipes is partially counteracted by frictional forces acting between the ground and the casing, with the shear stresses transferred through the PU foam bond. Therefore, the use of pre- insulated pipes has simplified the laying methods, employing cold laying instead of expansion facilities like compensators or U-bends, being so more cost effective. Pre-insulated pipes sandwich assembly composed of

7410-435: The population were Hispanic or Latino of any race. There were 15,303 households, out of which 24.5% had children under the age of 18 living with them, 36.6% were married couples living together, 16.3% had a female householder with no husband present, and 43.3% were non-families. Of all households, 32.9% were made up of individuals, and 9.2% had someone living alone who was 65 years of age or older. The average household size

7505-442: The population. There were 16,136 households, of which 26.6% had children under the age of 18 living with them, 35.3% were married couples living together, 14.9% had a female householder with no husband present, 4.2% had a male householder with no wife present, and 45.6% were non-families. Of all households, 35.0% were made up of individuals, and 11.1% had someone living alone who was 65 years of age or older. The average household size

7600-554: The region. The conference was held at the United States Naval Academy on November 26, 2007. The Maryland State House is the oldest in continuous legislative use in the United States. Construction started in 1772, and the Maryland legislature first met there in 1779. It is topped by the largest wooden dome built without nails in the country. The Maryland State House housed the workings of the United States government from November 26, 1783, to August 13, 1784, and

7695-666: The south shore, known from 1683 as "Town at Proctor's", then "Town at the Severn", became in 1694 "Anne Arundel's Towne" (after Lady Ann Arundell (1616–1649), the late wife of the late Cecilius Calvert, second Lord Baltimore , 1605–1675). In 1654, after the Third English Civil War , Parliamentary forces assumed control of the Maryland colony and Stone went into exile south across the Potomac River in Virginia. Per orders from Lord Baltimore, Stone returned

7790-399: The system heat storage units may be installed to even out peak load demands. The common medium used for heat distribution is water or superheated water , but steam is also used. The advantage of steam is that in addition to heating purposes it can be used in industrial processes due to its higher temperature. The disadvantage of steam is a higher heat loss due to the high temperature. Also,

7885-485: The town. 17th-century Annapolis was little more than a village, but it grew rapidly for most of the 18th century until the American Revolutionary War as a political and administrative capital, a port of entry , and a major center of the Atlantic slave trade . The Maryland Gazette , which became an important weekly journal, was founded there by Jonas Green in 1745; in 1769 a theatre opened; during this period also

7980-621: The traditional water tank. In Alberta, Canada the Drake Landing Solar Community has achieved a world record 97% annual solar fraction for heating needs, using solar-thermal panels on the garage roofs and thermal storage in a borehole cluster. In Stockholm, the first heat pump was installed in 1977 to deliver district heating sourced from IBM servers. Today the installed capacity is about 660 MW heat, using treated sewage water, sea water, district cooling, data centers and grocery stores as heat sources. Another example

8075-425: The world's biggest biomass boilers also is connected to this in parallel to the turbine. Furthermore, unit 2 comprises two separate gas turbines with a capacity of 110 MW each. Avedøre unit 2 has an electrical efficiency of 49%, which makes it one of the world's most efficient. This record high efficiency is obtained when the unit is only producing electricity. When also producing heat for district heating

8170-403: Was 2.30 and the average family size was 2.93. In the city, 21.7% of the population was under the age of 18, 9.3% from 18 to 24, 33.4% from 25 to 44, 23.7% from 45 to 64, and 11.9% was 65 years of age or older. The median age was 36 years. For every 100 females, there were 90.0 males. For every 100 females age 18 and over there were 86.8 males age 18 and over. The median income for a household in

8265-434: Was 2.34 and the average family size was 3.02. The median age in the city was 36 years. 20.8% of residents were under the age of 18; 9.9% were between the ages of 18 and 24; 31.1% were from 25 to 44; 25.3% were from 45 to 64; and 13% were 65 years of age or older. The gender makeup of the city was 47.8% male and 52.2% female. As of the census of 2000, there were 35,838 people, 15,303 households, and 8,676 families residing in

8360-547: Was also the site of the 1786 Annapolis Convention , which issued a call to the states to send delegates for the Constitutional Convention to be held the following year in Philadelphia . The Annapolis Peace Conference took place in 2007. Annapolis is the home of St. John's College , founded 1696. The United States Naval Academy , established 1845, is adjacent to the city limits. A settlement in

8455-480: Was created on the campus of St. John's College . The second location of Camp Parole would house over 20,000 and would be located where Forest Drive is currently. The third and final location was finished in late 1863 and would be placed near the Elkridge Railroad, as to make transportation of soldiers and resources easier before and allowing the camp to grow to its highest numbers. This area just west of

8550-437: Was flooded and many businesses and homes in outlying areas were damaged. The previous record was 6.35 feet (1.94 m) during a hurricane in 1933, and 5.5 feet (1.7 m) during Hurricane Hazel in 1954. Downtown Annapolis has high-tide "sunny day" flooding. A Stanford University study found that this resulted in 3,000 less visits and $ 172,000 in lost revenue for local business in 2017. From mid-2007 through December 2008,

8645-475: Was founded by an act of the Maryland legislature in 1696 and was opened in 1701. Its principal building, McDowell Hall, was originally to be the governor's mansion; although £4,000 was appropriated to build it in 1742, it was not completed until after the War of Independence. Located 25 miles (40 km) south of Baltimore and 30 miles (48 km) east of Washington, D.C. , Annapolis is the closest state capital to

8740-511: Was observed with estimated winds of 125 mph. The tornado dissipated immediately past U.S. Route 50 and U.S. Route 301. As announced by United States Secretary of State Condoleezza Rice , Annapolis was the venue for a Middle East summit dealing with the Israeli–Palestinian peace process , with the participation of Israeli Prime Minister Ehud Olmert , Palestinian President Mahmoud Abbas (" Abu Mazen ") and various other leaders from

8835-467: Was state of the art until the 1930s. These systems piped very high-temperature steam through concrete ducts, and were therefore not very efficient, reliable, or safe. Nowadays, this generation is technologically outdated. However, some of these systems are still in use, for example in New York or Paris. Other systems originally built have subsequently been upgraded. The second generation was developed in

8930-406: Was the impetus for the construction of Preble Hall. The museum has approximately 100,000 visitors each year. The Hammond-Harwood House , located at 19 Maryland Avenue, was built in 1774 for Matthias Hammond, a wealthy Maryland farmer. Its design was adapted by William Buckland from Andrea Palladio 's Villa Pisani to accommodate American Colonial regional preferences. Since 1940, when the house

9025-568: Was used in Pompeii , and in Chaudes-Aigues since the 14th century. Denmark Denmark has one geothermal plant in operation in Thisted since 1984. Two other plants are now closed, located in Copenhagen (2005-2019), and Sønderborg (2013-2018). Both suffered issues with fine sand and blockages The country's first large-scale plant is being developed near Aarhus, and by the end of 2030, it

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