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Several major US businesses failed in the 1990s due to factors like increased competition, failure to adapt to market changes, and poor management, including the iconic department store chain Woolworth's and PC manufacturer Compaq. Other notable failures include the defunct toy retailer KB Toys and Frito-Lay's fat-free "WOW! Chips" line, which failed due to digestive side effects.
Retail and department stores
Woolworth's: Faced increasing competition from stores like Walmart and Target, leading to the closure of its U.S. five-and-dime stores in 1997 before the parent company rebranded as Foot Locker.
KB Toys: Went bankrupt and vanished due to competition from big-box retailers and the rise of e-commerce.
Gantos: A women's clothing chain that filed for bankruptcy and liquidated its stores by the end of the decade.
Technology
Compaq: Once the largest PC supplier, it faltered due to product quality issues and an inability to keep up with low-cost competitors like Dell. The company was eventually acquired by Hewlett-Packard in 2002.
Etoys.com: An early online toy store that collapsed when the dot-com bubble burst.
Tiger Electronics: Its "Arzone" portable gaming device failed due to its blurry screen and clunky gameplay.
Food and drink
Frito-Lay WOW! Chips: The "fat-free" chips, made with Olestra, caused severe digestive issues for many consumers, leading to the product's failure.
Zima: This clear, carbonated malt beverage was marketed as a sophisticated alternative to beer but failed to gain traction with consumers.
Other
Blockbuster Video: While its collapse occurred in the early 2000s, its failure to adapt to streaming and buy Netflix was rooted in the 1990s, making it a notable example of a 90s-era business failing to look ahead

Several major US businesses failed in the 2000s due to issues like accounting scandals, failure to adapt to new technology, and a lack of innovation. Prominent examples include Enron and WorldCom (accounting fraud), Blockbuster and Polaroid (failure to adapt to digital streaming and photography, respectively), and the dot-com bubble failures like Pets.com and Webvan.
Failed due to accounting scandals
Enron: Once a leading energy company, its collapse in 2001 was one of the largest accounting scandals in history, says the FBI.
WorldCom: The telecommunications giant also collapsed due to a massive accounting scandal in 2002.

During the 2010s, many long-standing US businesses failed due to a combination of new technology, shifting consumer behavior, and heavy debt. The "retail apocalypse" was a primary driver, as e-commerce giants like Amazon displaced traditional brick-and-mortar stores.
Prominent failures in the 2010s
Retail
Toys "R" Us: Filed for bankruptcy in 2017 and closed all US stores in 2018. It struggled to compete with Amazon and Walmart and was burdened with massive debt from a leveraged buyout in 2005. The brand later attempted a comeback with a smaller footprint.
Sears Holdings Corp: The parent company of Sears and Kmart filed for bankruptcy in 2018. The iconic department store chain suffered a slow decline from intense competition from big-box and online retailers.
Borders: The bookstore giant filed for bankruptcy in 2011 and liquidated its remaining stores. It failed to adapt to the shift to online bookselling and e-readers, leaving its customers and website to its competitor, Barnes & Noble.
Payless ShoeSource: The discount shoe retailer filed for bankruptcy in 2017 and 2019, closing all 4,400 stores across 30 countries. It was unable to compete with online retailers and other discount stores.
RadioShack: Known for electronics and batteries, RadioShack filed for bankruptcy twice during the decade (2015 and 2017). It was a victim of changing tech trends and fierce online competition.
The Bon-Ton: The regional department store chain, which operated stores like Carson's and Younkers, filed for bankruptcy in 2018 and liquidated after not turning a profit since 2010.
American Apparel: The clothing retailer filed for bankruptcy in 2015 and 2016, weighed down by debt and sales declines. The brand now operates as an online-only business.
Entertainment
Blockbuster: The video rental chain, which once had over 9,000 stores, filed for bankruptcy in 2010. The company failed to adapt to the new competitive landscape of Netflix, Redbox kiosks, and streaming services.
Movie Gallery: This competitor to Blockbuster and parent of Hollywood Video filed for bankruptcy in 2010, resulting in the closure of all its 2,400 US locations.
Technology and others
Theranos: The blood-testing startup, founded by Elizabeth Holmes, was one of the most high-profile tech failures of the decade. The company, which was valued at $9 billion at its peak, dissolved in 2018 after it was exposed as fraudulent.
Eastman Kodak Co.: The film photography giant filed for Chapter 11 bankruptcy in 2012. The company, which invented the first digital camera, failed to capitalize on the digital revolution and was a "corporate America poster child" for a company that resisted transition.
BlackBerry: Once a leader in mobile devices, BlackBerry's popularity waned in the 2010s due to its slow adoption of touchscreen technology and app ecosystems. The company exited the smartphone business in 2016 to focus on cybersecurity.
Hummer: The SUV brand was discontinued in 2010 after parent company General Motors filed for bankruptcy the year before. The brand fell out of favor following the 2008 oil price spike and a shift toward fuel-efficient vehicles

Many US businesses failed in the 2020s, especially during the initial COVID-19 pandemic, including retailers like J.C. Penney, Neiman Marcus, J. Crew, and Brooks Brothers. Other significant failures included Bed Bath & Beyond, which went bankrupt in 2023, and Pier 1 Imports, Modell's Sporting Goods, and Art Van Furniture, which all filed for bankruptcy in 2020. Financial institutions like First Republic Bancorp and SVB Financial Group also failed.
Major retail bankruptcies in the 2020s
Bed Bath & Beyond: Filed for bankruptcy in 2023.
J.C. Penney: Filed for bankruptcy in 2020.
Neiman Marcus: Filed for bankruptcy in 2020.
J. Crew: Filed for bankruptcy in 2020.
Pier 1 Imports: Closed all stores after filing for bankruptcy in 2020.
Modell's Sporting Goods: Filed for bankruptcy in 2020.
Art Van Furniture: Filed for bankruptcy in 2020.
Brooks Brothers: Filed for bankruptcy in 2020.
Tuesday Morning: Filed for bankruptcy in 2020.
Sur La Table: Closed many stores during its 2020 bankruptcy process.
Lord & Taylor: Filed for bankruptcy in 2020.
Financial sector failures
First Republic Bancorp: Failed during the banking turmoil in 2023.
SVB Financial Group: Failed during the banking turmoil in 2023

Since 2020, the U.S. has experienced a historic surge in new business applications, with record-breaking numbers filed in 2021 and 2023. This sustained period of high business creation is a significant shift from previous decades and was primarily driven by pandemic-induced disruptions and a changing labor market.
New business applications per year
Data based on information from the U.S. Census Bureau.
Year     Business Applications    Change vs. Prior Year    Notes
2020    4.4 million    +24.5%    A sharp increase during the first year of the pandemic, with applications soaring 51% higher than the 2010–2019 average.
2021    5.4 million    +23.5%    A new annual record for business applications, largely influenced by pandemic-era economic and labor shifts.
2022    5.0 million    -6.0%    A slight dip from the 2021 peak, but applications remained well above pre-pandemic levels.
2023    5.5 million    +8.1%    The highest number of new business applications ever recorded in a calendar year.
2024    5.21 million    -4.77%    A moderation from the 2023 peak, though still a period of robust entrepreneurship.
2025    Projected millions    +3.15% (partial data)    As of August 2025, over 3.5 million applications had been submitted, indicating that a high level of business formation is continuing.
Key drivers and characteristics of the boom
Pandemic as a catalyst: The COVID-19 pandemic fueled entrepreneurship by necessity, as many people who lost their jobs started their own businesses.
Shift in work: The rise of remote work and the gig economy gave people more flexibility to pursue entrepreneurial ventures.
Growth in specific sectors: Initial growth was most significant in sectors that supported the "home-based economy," such as e-commerce (retail trade), transportation, and personal services.
Increased diversity: New entrepreneurs in the 2020s have been more diverse than in the past, with women, Black, Asian, and Hispanic shares of self-employed Americans near all-time highs.
Mix of high and low-propensity businesses: The surge included both "high-propensity" businesses, which are likely to hire employees, and a large number of sole proprietorships and ventures less likely to have a payroll.
Long-term outlook
This era of heightened business creation marks a new, higher "plateau" for entrepreneurship in the United States. The surge has proven to be more than a temporary blip, representing a lasting shift in the country's economic landscape

The 1960s saw the rise of new businesses in various sectors, including fast food franchises like Domino's Pizza and the first discount retailers such as Kmart, Walmart, and Target. The decade was also characterized by the growth of large conglomerates, the development of shopping centers, and the establishment of tech and service companies like Medtronic, Dolby Laboratories, and Instinet.
Retail and consumer goods
Discount Retailers: Kmart was the first, opening in 1962, followed by Walmart and Target in the same year, which introduced a new model of bulk purchasing to offer lower prices.
Franchises: The franchise boom was in full swing, with chains like Domino's Pizza, McDonald's, and Holiday Inn expanding rapidly.
Shopping Centers: More than 8,000 shopping centers were built during the decade, changing how and where people shopped.
Technology and services
Tech and Manufacturing: Companies like Medtronic, Teradyne, and Dolby Laboratories were founded.
Financial Services: NationsBank, Duane Reade, and Jackson Hewitt were among the new financial and service businesses.
Logistics and communication: Sea-Land Service pioneered containerized shipping, and Instinet launched an electronic system for institutional investors.
Conglomerates and hospitality
Conglomerates: A wave of business acquisitions led to the formation of large, diversified conglomerates like ITT Corp. and Litton Industries.
Hospitality: New hotels were built to accommodate the growing population, and new restaurant chains emerged, such as the Playboy Club

he 1970s saw the establishment of many new US businesses, particularly in the tech sector with the rise of semiconductors and venture capital firms like Sequoia Capital and Kleiner Perkins. Other notable companies started in this decade include retail giants like Days Inn, Chili's, and Chi-Chi's; technology and software companies such as Atari and Microsoft; and others like Intel and Acadian Ambulance. The business landscape also reflected broader societal changes, with the emergence of niche stores catering to specific subcultures, such as record stores and boutiques.
Technology and computing
Intel: A major player in the semiconductor industry, which saw significant growth in memory products like the Intel 1103 DRAM.
Microsoft: Founded in 1975 by Bill Gates and Paul Allen.
Atari, Inc.: Founded in 1972, it became a major force in the video game industry.
Venture capital firms: The decade saw the founding of Silicon Valley's top venture capital firms, such as Sequoia Capital and Kleiner Perkins Caufield & Byers, both established in 1972.
Retail and services
Days Inn: A hotel chain that began in the 1970s.
Chili's and Chi-Chi's: Two popular restaurant chains that were established during this period.
Apple Computers: Though not a business startup in the 1970s, the company was founded in 1976.
Specialty stores: A rise in niche stores, including record stores and boutiques, reflected the segmentation of the market and counterculture movements.
American Home Shield: A company that was established in 1971.
Other notable businesses
Amdahl Corporation: A computer company established in the 1970s.
Acadian Ambulance: A company that was established in 1971.
DeLorean Motor Company: A car company established in 1975

The 1980s saw the establishment of many new US businesses, spanning various sectors like technology, retail, and direct sales. Notable tech companies founded during this decade include Adobe Inc. and Synnex. Retail and service-based companies like The UPS Store and ShowBiz Pizza Place also emerged. The direct selling industry experienced significant growth, with companies like Herbalife and The Pampered Chef being founded in the 1980s.
Technology and software
Adobe Inc.: A company that would become a giant in the software industry.
Synnex: A technology services company.
Access Software: A video game developer.
Symbolics: A computer company specializing in Lisp machines.
Retail and food service
ShowBiz Pizza Place: A family entertainment center and restaurant chain.
The UPS Store: A retail franchise focused on packing and shipping services.
Amy's Kitchen: A company that prepares and sells frozen organic meals.
Sierra Nevada Brewing Co.: A craft brewery.
Direct sales
Herbalife: A company that sells nutrition, weight management, and skincare products.
The Pampered Chef: A company specializing in kitchen tools.
Nu Skin: A company in the beauty and wellness sector.
Stampin' Up!: A company focused on paper crafting supplies.
Other sectors
Aéropostale: An American lifestyle clothing company.
Airgas: A distributor of industrial gases.
American Graphics Institute: A company providing design and technology training

Several major U.S. businesses either left or went out of business in the 1990s, often due to bankruptcy or acquisition. Examples include the major retailer Montgomery Ward and the electronics company Compaq Computers, which was bought by Hewlett-Packard in 2002. The decade also saw major shifts in retail, leading to the bankruptcy and closure of numerous smaller chains and the decline of large department stores like Montgomery Ward, according to this Quora post and this Facebook post. 
Montgomery Ward: A major department store that struggled with competition from big-box retailers and filed for bankruptcy, eventually closing all stores in 2001.
Compaq: A computer company that was a dominant force in the 1990s but was acquired by Hewlett-Packard in 2002, effectively ending its independent existence.
Edison Brothers Stores: A parent company to many 90s retailers like Coconuts and Sam Goody's, it went bankrupt in the 1990s and sold off its various brands.
Circuit City: The electronics retailer struggled with competition and filed for bankruptcy in 2008, closing all its stores.
Tower Records: The once-dominant music retailer filed for bankruptcy in 2006.
Radio Shack: The electronics chain filed for bankruptcy in 2015, marking the end of an era for the company.
Blockbuster: The video rental giant was unable to compete with the rise of streaming services and filed for bankruptcy in 2010.
Toys "R" Us: The toy retailer, once a symbol of childhood, filed for bankruptcy in 2017 and closed its stores, though the brand has since made a comeback.
Other businesses that left in the 90s
Pan Am: The airline ceased operations in 1991.
Kodak: The photography giant struggled to adapt to the digital age, filing for bankruptcy in 2012.
Enron: The energy company was involved in a massive accounting scandal that led to its collapse in 2001.
Polaroid: The instant photography company filed for bankruptcy in 2001.

Some of the most prominent U.S. businesses to leave or disappear during the 2000s were major brands in technology, retail, and manufacturing. The reasons they left varied, including failure to adapt to new technology, poor management, intense competition, and—in the case of companies that relocated overseas—corporate tax inversions.
Companies that went out of business
Blockbuster: The video rental giant failed to adapt to the rise of online DVD rentals (like Netflix) and streaming services. The company filed for bankruptcy in 2010.
Compaq: Once the largest personal computer supplier, Compaq was acquired by Hewlett-Packard in 2002. Internal conflicts and poor strategy weakened the brand, which was phased out by HP.
Enron: The energy company collapsed in 2001 due to a massive accounting fraud scandal that hid billions in debt.
Lehman Brothers: The 150-year-old investment bank declared bankruptcy in 2008, holding over $600 billion in assets. Its collapse is considered a significant event that contributed to the global financial crisis.
Limewire: This popular peer-to-peer file-sharing software was shut down in 2010 after a U.S. federal court ruled that it had committed copyright infringement.
WorldCom: This telecommunications rival to AT&T was undone by a major accounting fraud scandal in the early 2000s. It filed for bankruptcy and was later acquired by Verizon.
Borders: The book and music retailer struggled to compete with online competitors and filed for bankruptcy in 2011.
Companies that moved overseas
Anheuser-Busch: The St. Louis-based beer maker was acquired by the Belgian company InBev for $52 billion in 2008. The new parent company, AB InBev, is headquartered in Belgium.
Seagate Technology: The hard-drive manufacturer moved its global headquarters to the Cayman Islands in 2000 and then to Ireland in 2010.
Tyco International: This diversified manufacturing conglomerate relocated its incorporation to Bermuda in 1997. It faced a major scandal in the early 2000s involving its top executives, who were convicted of looting the company.
Accenture: The consulting firm, spun off from the accounting firm Arthur Andersen, reincorporated in Bermuda in 2001.
IBM's Personal Computer division: In 2005, IBM sold its PC division to the Chinese company Lenovo. This move enabled IBM to focus on software and services.
Cooper Industries: This electrical products manufacturer reincorporated in Bermuda in 2002. It was acquired by Eaton in 2012.
Ingersoll-Rand: The industrial manufacturer moved its incorporation to Bermuda in 2002. It has since relocated its official domicile to Ireland.
Factors that drove companies to leave the US
Acquisitions and foreign ownership: Many American brands, such as Sunglass Hut, Ben & Jerry's, and Anheuser-Busch, were acquired by foreign companies during this era.
Corporate tax inversions: To lower their corporate tax burdens, some companies reincorporated their businesses overseas, often in countries with lower tax rates.
Failure to innovate: Companies like Blockbuster and Compaq were unable to adapt to new technologies and market shifts, leading to their demise.
Financial crisis and poor management: The 2008 financial crisis devastated many businesses, including Lehman Brothers. Other companies, like WorldCom and Enron, suffered from corporate misconduct and accounting scandals.
Shifting manufacturing overseas: The trend of outsourcing manufacturing accelerated in the 2000s. Companies seeking lower labor costs and less regulation moved production to countries like China and Mexico

Multiple U.S. businesses either left the country, went out of business, or moved significant operations overseas during the 2010s due to factors such as globalization, shifting consumer trends, and tax laws.
Iconic companies that went defunct
Blockbuster: The video rental giant declared bankruptcy in 2010. It had failed to compete with the rise of streaming services like Netflix and mail-order rentals.
Borders: The bookstore chain went out of business in 2011. Like Blockbuster, it was unable to adapt to the rapidly changing retail landscape dominated by online sellers like Amazon.
RadioShack: A decades-old electronics retailer, RadioShack began closing stores in 2010 and filed for bankruptcy in 2015.
Toys R Us: After years of competition from big-box retailers and e-commerce, the iconic toy store declared bankruptcy in 2017.
Barneys New York: The luxury department store closed its doors in 2019 after facing financial difficulties throughout the decade.
American Apparel: This apparel retailer, known for its "Made in the USA" manufacturing, lost its cultural relevance and was purchased out of bankruptcy by a Canadian company in the mid-2010s.
Companies that moved their headquarters (corporate inversions)
Corporate inversions were a major trend in the early 2010s, where U.S. companies would merge with smaller foreign firms to reincorporate abroad and reduce their tax burden. The U.S. government put the kibosh on such deals in 2014.
Burger King: In 2014, the fast-food chain merged with Canadian company Tim Hortons to form Restaurant Brands International, which was headquartered in Canada.
Seagate Technology: The hard-drive manufacturer officially moved its global headquarters to Ireland in 2010.
Valient: The pharmaceutical company merged with Canada's Biovail in 2010 and relocated its headquarters to Canada.
Companies that offshored operations
A large number of companies offshored manufacturing and other operations during the 2010s to reduce costs, leading to job losses in the U.S..
Cisco Systems: Between 2010 and 2014, the networking company saw its percentage of overseas workers rise from 25% to 46%, primarily in China and India.
Hewlett-Packard (HP): In 2010, the company laid off human resources employees in the U.S., transferring their functions to Panama.
Hilton Worldwide: Also in 2010, the hotelier moved a reservations center to the Philippines to save money.
Ford Motor Company: A significant portion of Ford's workforce was moved out of North America during the 2010s. By 2009, the North American workforce made up only 37% of its total payroll.
JPMorgan Chase: The bank moved its telephone banking operations to the Philippines in 2010

In concentrated solar power (CSP) systems, thermal oil is used as a heat transfer fluid (HTF) and can also function as a thermal energy storage (TES) medium. There are no standardized, universally applicable charts for the volume of thermal oil, as the required volume is specific to the design of each individual plant and its storage capacity. 

The volume of thermal oil in a CSP plant depends on the system's design and operating parameters, including: 
Total system capacity:
The overall power output of the plant.Collection area:
The size of the solar field (e.g., parabolic troughs) that collects the solar energy.
Storage capacity:
The number of hours the plant can operate on stored thermal energy after the sun sets.
Type of CSP technology:
Parabolic trough systems are most commonly associated with thermal oil, while solar tower systems often use molten salt, which allows for higher operating temperatures.
Thermal oil properties:
The specific heat, density, and operating temperature range of the chosen thermal oil (e.g., Therminol 66). How thermal oil volume is calculated for a CSP plant While no generic chart exists, the total thermal oil volume is derived from several key calculations: 

1. Thermal energy storage (TES) volume: This is the most significant part of the thermal oil volume. It is calculated based on the required storage capacity and the oil's thermal properties. Formula:\(V_{\text{storage}}=\frac{E_{\text{storage}}}{\rho \cdot c_{p}\cdot \Delta T}\) \(V_{\text{storage}}\) = Volume of thermal oil in the storage tanks (m\({}^{3}\))\(E_{\text{storage}}\) = Total thermal energy required for storage (in Joules or kWh)\(\rho \) = Density of the thermal oil (kg/m\({}^{3}\))\(c_{p}\) = Specific heat capacity of the thermal oil (J/kg·K)\(\Delta T\) = The temperature difference between the hot and cold oil in the two-tank storage system (K) 

2. Heat transfer fluid (HTF) volume: This is the volume of oil circulating through the solar collector field, piping, and heat exchangers. Formula:\(V_{\text{HTF}}=V_{\text{collectors}}+V_{\text{piping}}+V_{\text{exchangers}}\) \(V_{\text{collectors}}\) = Volume of oil inside the receiver tubes of the parabolic troughs.\(V_{\text{piping}}\) = Volume of oil in the network of pipes connecting the solar field to the storage and power block.\(V_{\text{exchangers}}\) = Volume of oil within the heat exchangers that transfer heat to the power cycle (e.g., steam generator). 

3. Expansion volume: Thermal oil, like any fluid, expands and contracts with temperature changes. An expansion vessel is required to accommodate this volume change and maintain system pressure. 

Example:
Thermal storage volume calculation The following example illustrates the calculation for a 100 MW CSP plant with 6 hours of thermal oil storage. 

Assumptions: 
Storage capacity: 6 hoursHeat transfer fluid:

Therminol 66

Thermal power rating:
100 MWth (assuming a 100 MW electric power output, the thermal power is higher due to turbine efficiency)Temperature difference (\(\Delta T\)): 390°C (hot oil) - 290°C (cold oil) = 100 KOil density (\(\rho \)): ~780 kg/m³ at the average temperatureSpecific heat (\(c_{p}\)): ~2.3 kJ/kg·K Calculation: Total thermal energy (\(E_{\text{storage}}\)):\(E_{\text{storage}}=\text{Power}\times \text{Time}=100\text{\ MWth}\times 6\text{\ h}=600\text{\ MWh}\)Convert to Joules:\(600\text{\ MWh}\times 3.6\times 10^{9}\text{\ J/MWh}=2.16\times 10^{12}\text{\ J}\)Required storage volume (\(V_{\text{storage}}\)):\(V_{\text{storage}}=\frac{E_{\text{storage}}}{\rho \cdot c_{p}\cdot \Delta T}=\frac{2.16\times 10^{12}\text{\ J}}{(780\text{\ kg/m}^{3})(2300\text{\ J/kg\cdotp K})(100\text{\ K})}\approx 12,000\text{\ m}^{3}\) This is the volume for the thermal energy storage tanks alone.

The total volume would also include the fluid in the collector field and piping, which could add another 10% to 20% to the total.

Factors that determine the quantity of solar oil include:

System scale:
The quantity of thermal oil is a function of the solar collector area and the thermal energy storage tank volume. Larger systems require significantly more oil.

Thermal energy storage (TES):
If the system uses thermal oil for energy storage, a large tank is required, which dramatically increases the oil quantity. Some studies use storage tanks ranging from 8 m³ to 30 m³ or more. Other designs use different storage media, like molten salt or ceramic rocks, which would eliminate or reduce the need for thermal oil.

Specific project design:
Research and project reports involving solar ORC systems often mention the specific quantities used for their particular setup. For example, a 2017 study mentions a 10 m³ thermal oil storage tank used with a 160 m² collector area.

AI Overview
In an experimental ORC (Organic Rankine Cycle) solar car, the alternator or generator can run at very high speeds. In one specific study by ORC Orosz, a maximum generated power of 6.3 kW was produced at a speed of 20,000 RPM.

Factors that influence the alternator's RPM

The rotational speed is not fixed and depends on several factors:

System optimization:
The control system of the ORC balances the variable heat input from the solar field with the fixed characteristics of the expander and alternator. This dynamic control is used to maintain optimal operating parameters, which can influence the RPM.

Optimal operating point:
The alternator RPM can be controlled to maintain efficiency. In the ORC Orosz study, the isentropic efficiency of the expander peaked at 35.2% at 20,000 RPM and was 27% at 15,000 RPM.

Load and power output:
The speed will also vary based on the electrical load and the desired power output. In the example given, the peak power was generated at 20,000 RPM, but the system would run at different speeds to meet lower power demands.
This high-speed operation is a characteristic of some specialized generators used in ORC systems, which are very different from the standard alternators found in conventional combustion engine vehicles.

AI Overview
To size a solar thermal expansion tank, first calculate the total volume of the solar loop, including pipes, collectors, and heat exchanger. Next, determine the expected thermal expansion of the fluid, which is a percentage of the total volume based on the temperature difference. Finally, select a tank with an acceptance volume that is at least the calculated amount of expansion, and a total tank volume that is greater than the total system volume, using manufacturer's guidelines or a formula like the one provided by SunMaxx Solar to ensure proper pressure management.

This video explains how to size and select an expansion tank, including factors like system volume and pressure:

1. Calculate total system volume     Add the volume of the fluid in the pipes to the volume of the solar collectors and the heat exchanger. Use manufacturer data sheets for the collectors and heat exchanger. Calculate pipe volume by multiplying the total length of the pipe runs by the fluid capacity per 100 feet (found in tables) based on pipe size and type.  .CM8kHf text{fill:var(--m3c11)}.CM8kHf{font-size:1.15em}.j86kh{display:inline-block;max-width:100%}            2. Calculate the required acceptance volume     This is the volume the tank needs to accommodate as the fluid expands.  Fluid expansion is calculated based on the fluid type and the temperature change. For example, a common propylene glycol solution expands by slightly less than 5% between \(35^{\circ }F\) and \(200^{\circ }F\).  You can use the following formula to estimate the acceptance volume: Acceptance Volume = System Volume: (\(V\)) x Coefficient of Thermal Expansion (\(\Delta T\) between max and min temp) x Safety Factor              3. Select the expansion tank     Acceptance Volume: Choose a tank whose "acceptance volume" is greater than the calculated acceptance volume from the previous step.  Total Volume: The "total volume" of the selected tank must be greater than the total system volume you calculated in step 1.  It is better to slightly oversize the tank than to undersize it.  If you are unsure, consider selecting a tank one size larger than what the calculations suggest, especially in high-temperature systems. 

To boil liquid Freon at atmospheric pressure, the required temperature depends on the specific type of refrigerant, as "Freon" refers to a family of different chemicals.
Common Freon refrigerants and their boiling points at atmospheric pressure:

• [] Freon-12 (R-12): Boils at approximately -29.8°C (-21.6°F). This refrigerant is an ozone-depleting substance and has been largely phased out.
  [] Freon-22 (R-22): Has a boiling point of around -40.8°C (-41.4°F). Like R-12, this refrigerant is a hydrochlorofluorocarbon (HCFC) and is being phased out.

• Freon 410A (R-410A): A blend that boils at approximately -51.6°C (-60.8°F). It is an HFC refrigerant and a common replacement for R-22.

Key considerations
Boiling temperature is dependent on pressure. The boiling points listed above are specifically for atmospheric pressure. In a refrigeration system, the refrigerant's pressure is varied to control the boiling and condensing temperatures. For example, to raise Freon's boiling point, its pressure must be increased

The temperature required to boil liquid "freon" varies significantly based on the specific type of refrigerant and, most importantly, the system's pressure. For example, at atmospheric pressure, R-22 boils at approximately \(-40^{\circ }F\) (\(-40^{\circ }C\)). However, in a typical HVAC system, pressure is much higher in the condenser, which raises the boiling point to a much higher temperature, allowing it to release heat. Pressure is the key factor: The temperature at which a refrigerant boils is called its saturation temperature, and it changes drastically with pressure. Higher pressure leads to a higher boiling point.Examples of boiling points:R-22: Boils at about \(-40^{\circ }F\) (\(-40^{\circ }C\)) at atmospheric pressure, but can boil at a higher temperature of \(+20^{\circ }C\) at a pressure of 6 atmospheres.R-410A: Boils at \(-51^{\circ }C\) at atmospheric pressure.R-134a: Boils at \(-26^{\circ }C\) at atmospheric pressure.Evaporator vs. condenser: A refrigerant enters the evaporator as a cold, low-pressure liquid and boils at a very low temperature to absorb heat. In the condenser, pressure is increased, which raises the boiling point to a higher temperature so the refrigerant can release heat to the surroundings. 

AI Overview     Based on your query, here is an explanation of solar thermal power for hot water, how "watts" and "watt-hours" apply, and how to represent this information using BBCode for a forum or web page. Solar thermal power for hot water Solar thermal systems heat water directly using sunlight, rather than converting it to electricity first. Because of this, the energy output is measured in heat units, not electrical units. How it works: Solar thermal collectors (flat-plate or evacuated-tube panels) on a roof absorb solar radiation to heat a fluid. This fluid then circulates through a heat exchanger to transfer the heat to a domestic hot water tank.High efficiency: Solar thermal collectors can convert up to 80% of the sun's energy into heat for water, which is a much higher conversion rate than typical photovoltaic (PV) panels. However, this is not an apples-to-apples comparison, as PV produces electricity, which can be used for a wider variety of purposes."Watts" in context: When discussing solar thermal systems, the term "watts" (\(W\)) is used to describe the instantaneous rate of heat transfer, typically expressed as thermal kilowatts (\(kW_{th}\)). A common conversion factor is \(0.7\) \(kW_{th}\) per square meter of collector area. Electrical watts (\(W\)) are only relevant for the small amount of power needed to run pumps and system controls. Calculating and expressing energy output For solar thermal, it is most accurate to measure the total energy output over time. Watt-hours (\(Wh\)): This is a unit of energy equal to the power in watts multiplied by the time in hours. For solar thermal, this would represent the total thermal energy (\(Wh_{th}\)) produced. For example, a system with a peak thermal output of 3.5 \(kW_{th}\) that runs for 5 hours would produce \(3,500\) \(W_{th}\) * \(5\) hours = \(17,500\) \(Wh_{th}\), or \(17.5\) \(kWh_{th}\) of thermal energy.Standard ratings: The Solar Rating & Certification Corporation (ICC-SRCC) provides standard ratings for collectors in both thermal kilowatt-hours per day and thousands of BTU per day. A typical system might produce 10–15 \(kWh_{th}\) per panel per day. BBCode for formatting BBCode is a simple markup language used on many web forums. Here is how to format text related to solar thermal power calculations for a forum post. Bold: Thermal Power:Italic: Energy output can vary based on conditions.List:bbcode

• Panel Type: Evacuated Tube

• Peak Output: 3.5 kW[sub]th[/sub]

• Total Daily Energy: 17.5 kWh[sub]th[/sub] (over 5 sun-hours)

Formatted example:bbcodeMy Solar Thermal System Performance

This is an example of the output from a solar thermal system used for hot water.

• Collector Type: Evacuated Tube

• Gross Area: 3.5 m[sup]2[/sup]

• Rated Thermal Power: ~2.5 kW[sub]th[/sub] (Standard conditions)

• Typical Daily Energy Output:

  • Summer (High Radiation): 15-20 kWh[sub]th[/sub]

  • Winter (Low Radiation): 5-10 kWh[sub]th[/sub]

AI Overview     To calculate the energy output of a solar thermal hot water system, use the specific heat formula to find the thermal energy needed to heat the water. Then, account for the system's efficiency and BBCode units. Step 1: Calculate the thermal energy needed Use the specific heat formula to determine the energy required to heat a specific volume of water:Energy (in Joules) = mass (m) × specific heat of water (c) × change in temperature (ΔT) Variables: Mass (m): The mass of water you need to heat. A common conversion is 1 kilogram (kg) per liter (L) of water.Specific heat of water (\(c\)): A constant value of approximately 4.186 Joules per gram per degree Celsius (\(4186\text{\ J/kg}\degree \text{C}\)).Change in temperature (\(\Delta T\)): The desired hot water temperature minus the incoming cold water temperature, in degrees Celsius. Example calculation:To find the energy (in Joules) required to heat 100 liters of water from 10°C to 55°C: Mass (m): \(100\text{\ L}\times 1\text{\ kg/L}=100\text{\ kg}\)Specific heat (\(c\)): \(4186\text{\ J/kg}\degree \text{C}\)Change in temperature (\(\Delta T\)): \(55\degree \text{C}-10\degree \text{C}=45\degree \text{C}\) Equation:Energy (J) = \(100\text{\ kg}\times 4186\text{\ J/kg}\degree \text{C}\times 45\degree \text{C}\)Energy (J) = \(18,837,000\text{\ J}\) Step 2: Convert to Watt-hours (Wh) Energy is commonly measured in kilowatt-hours (kWh) or watt-hours (Wh). There are 3.6 million Joules in a kilowatt-hour. Convert from Joules to Watt-hours:1 Watt-hour = 3600 Joules Equation:Energy (Wh) = \(18,837,000\text{\ J}\div 3600\text{\ J/Wh}\)Energy (Wh) = \(5232.5\text{\ Wh}\) Step 3: Estimate for BBCode formatting To represent this calculation in BBCode format, which is often used on forums and is a variation of HTML, you would structure the output with bolding for emphasis, and use code blocks if available for formulas. Example BBCode: Calculating Solar Thermal Power for Hot Water

1. Calculate Thermal Energy Needed
Energy (in Joules) = mass * specific heat * temperature change
- Mass: 100kg (for 100L of water)
- Specific Heat: 4186 J/kg°C
- Temperature Change: 45°C (from 10°C to 55°C)

Energy (J) = 100 * 4186 * 45 = 18,837,000 J

2. Convert to Watt-hours (Wh)
1 Wh = 3600 J

Energy (Wh) = 18,837,000 / 3600 = 5232.5 Wh
Additional factors affecting output The calculation above is for the thermal energy required, not the solar panel output. To get a more realistic estimate of the solar thermal system's performance, you must also consider: System efficiency: Real-world systems lose energy. A factor should be applied to account for these losses.Irradiation: The amount of available sunshine, which varies by location, time of day, and weather.Collector area: The size of the solar collector panels directly impacts the amount of heat absorbed.Solar fraction: The percentage of the total hot water load that the solar thermal system is expected to provide. For a more comprehensive analysis, you can use specialized software or online calculators, such as the one offered by the U.S. Department of Energ

BTU (British Thermal Unit) Calculations

1 BTU=1 DEGREE FARENHEIT INCREASE IN ONE POUND OF WATER.

8.34 POUNDS IN ONE GALLON

BTU EXAMPLE:
Incoming water 50F outgoing water 120F 120 - 50 = DELTA T 70F
BTU's for 1 gallon of water is 70 (delta T) * 8.34 (pounds per gallon) = 583.8 BTU's
Flow Rate 2 Gallons per Minute
2 Gallons * 60 minutes = 120 Gallons per hour
120 Gallons * 583.8 BTU's per Gallon = 70,056 BTU's per Hour

Solar Constant (measured outside the earth's atmosphere by satellite) is about 1.3 kilowatts (1,366 watts) per square meter (kW/m²)
The maximum value is about 1 Kw (1,000 watts) per sq meter, measured at the earth's exposed surface, when the sun is directly overhead.

Solar Insolation Maximum sun energy (irradiance) reaching the surface of the earth over a given time period.

kWh (kiloWatt hour) to BTU examples:
1 kWh = 3,412 btu's (per square meter when the sun is directly overhead)
90,000 btu's x 0.00029307108 = 26.37 kWh

Correct Flow Rates for Evacuated Tube Collector

0.026 to 0.066 Gallons per Minute per Tube
0.1 to 0.25 Liters per Minute per Tube

Volume Equivalents

231 CUBIC INCHES PER GALLON

7.481 GALLONS PER CUBIC FOOT

1.02 GALLONS PER 100' OF ½" PIPE

2.29 GALLONS PER 100' OF ¾" PIPE

4.08 GALLONS PER 100' OF 1" PIPE

Energy Conversions

1 kWh (kilo watt hours) = 3412.1415 BTU's

1 BTU = 0.00029307108 kWh

Btu Content of Common Energy Units

1 barrel (42 gallons) of crude oil = 5,800,000 Btu
1 gallon of gasoline = 124,000 Btu (based on U.S. consumption, 2008)
1 gallon of diesel fuel = 139,000 Btu
1 gallon of heating oil = 139,000 Btu
1 barrel of residual fuel oil = 6,287,000 Btu
1 cubic foot of natural gas = 1,028 Btu (based on U.S. consumption, 2008)
1 gallon of propane = 91,000 Btu
1 short ton of coal = 19,988,000 Btu (based on U.S. consumption, 2008)
1 kilowatthour of electricity = 3,412 Btu
Formulas

DELTA T = TEMPERATURE DIFFERENCE BETWEEN TWO VALUES (100F-90F = 10F DELTA T)

C TO F CONVERSION (C*1.8) + 32 = F

F TO C CONVERSION (F - 32.0) / 1.8 = C

LBS * 0.453592 = KILOGRAMS

KILOGRAMS * 2.204623 = POUNDS

GALLONS * 3.785412 = LITERS

LITERS * 0.264272 = GALLONS

QUARTS * 0.946353 = LITERS

LITERS * 1.056688 = QUARTS

Following the Space Shuttle Columbia disaster in 2003, President George W. Bush announced the Vision for Space Exploration in 2004, which started the transition away from the Space Shuttle and toward new deep-space exploration programs. However, the program announced in 2004 was the now-canceled Constellation program—not Artemis. The Space Shuttle did not fully retire until 2011, and the Artemis program was not established until 2017.

2004: Vision for Space Exploration and the Constellation program

The decision:
In January 2004, after the loss of Space Shuttle Columbia and its crew, President Bush announced the Vision for Space Exploration. This initiative called for the Space Shuttle fleet to be retired after completing assembly of the International Space Station (ISS).

The goal:
The Vision set out a plan for developing a new crewed vehicle to return humans to the Moon and later travel to Mars and beyond.

The program:
The Constellation program was formed in 2005 to fulfill this vision. It involved the development of two new launch vehicles, the Ares I for crew and the Ares V for cargo, as well as the Orion crew capsule and the Altair lunar lander.
The path from Constellation to Artemis

Constellation's cancellation:
Following an independent review that found Constellation to be over budget and behind schedule, President Barack Obama formally canceled the program in 2010.

The start of Artemis:
In 2017, President Donald Trump established the Artemis program. The new program repurposed the Orion crew capsule from the Constellation program and adapted much of the launch hardware to create the Space Launch System (SLS).

The end of the Space Shuttle
Final flights:
The Space Shuttle program continued flying missions to assemble the ISS after the 2004 announcement.

Official retirement:
The program officially ended with the landing of Space Shuttle Atlantis on July 21, 2011. A six-year gap followed where American astronauts relied on Russian Soyuz vehicles to get to the ISS, before the Commercial Crew Program began.

Duffy's comments follow months of mounting pressure within NASA to speed up its Artemis lunar program and push SpaceX to make greater progress on its Starship lunar lander, while China progresses toward its own goal of sending humans to the moon by 2030.
It represents a major shift in NASA's lunar strategy, starting a new competitive juncture in the program for a crewed moon lander just two years before the scheduled landing date. Blue Origin is widely expected to compete for the mission, while Lockheed Martin (LMT.N), opens new tab has indicated it would convene an industry team to heed NASA's call.
Starship, picked by NASA in 2021 under a contract now worth $4.4 billion, faces a 2027 moon landing deadline that agency advisers estimate could slip years behind schedule, citing competing priorities. Musk sees Starship as crucial to launching larger batches of Starlink satellites to space and eventually ferrying humans to Mars, among other missions.

"They do remarkable things, but they're behind schedule," Duffy said of SpaceX's lunar lander work, adding President Donald Trump wants to see the mission take place before his White House term ends in January 2029.
The move is a significant change under the agency's acting leadership, and as the White House and Duffy begin to reopen the nomination process for a permanent administrator. Billionaire entrepreneur and SpaceX customer-astronaut Jared Isaacman, an ally of Musk's, is in talks to reclaim his nomination that had been yanked by Trump over the summer.
Musk shrugged off the specter of more competition in a social media post.
"SpaceX is moving like lightning compared to the rest of the space industry," the SpaceX CEO wrote on X, replying to a user on Monday. "Moreover, Starship will end up doing the whole Moon mission. Mark my words."

The mission involving SpaceX, Artemis 3, would be the first human lunar landing since Apollo 17 in 1972.
Bezos' space company Blue Origin, with its Blue Moon lander in development, has a similar lunar landing contract awarded by NASA in 2023 but for later Artemis moon missions. The company had protested NASA's initial decision to only pick SpaceX in 2021 and fought for years to convince the agency and lawmakers to select another proposal as a redundancy.
Duffy's reference to Blue Origin on Monday suggests Bezos' space company could contend for Artemis 3.
Blue Origin has been developing its Blue Moon lander in Florida with relatively little public attention under a contract worth roughly $3 billion. SpaceX has been developing Starship in Texas in a whirlwind campaign of test-to-failure demonstration missions, but NASA has grown uneasy with a lack of progress on lunar lander-specific development milestones.

NASA's multibillion-dollar Artemis program is a series of missions involving multiple contractors aimed at returning humans to the moon for a long-term presence there. Artemis 3 has been planned for 2027 with SpaceX's Starship.
Artemis 2, opens new tab, a 10-day flight around the moon and back involving systems built by Boeing (BA.N), opens new tab, Northrop Grumman (NOC.N), opens new tab and Lockheed Martin (LMT.N), opens new tab, is on track for April and could get moved up to February, he added.
Bezos and Blue Origin CEO Dave Limp reportedly spoke with Trump over the summer when the Republican president was feuding with Musk, a supporter in the 2024 election who was tapped to lead efforts to cut the federal government known as DOGE.

The current approved annual Starship launch rate is 25, following an approval by the FAA in May 2025. This is a significant increase from the previous limit of five, and SpaceX's goal is to increase this further to a weekly launch cadence, which could be achieved in 2026. However, the actual launch rate has been much lower than the approved maximum, with a total of five orbital flights by mid-October 2025.

Approved rate:
The FAA has approved up to 25 annual Starship/Super Heavy orbital launches from the Boca Chica launch site.
Previous rate: Before the recent approval, the limit was five launches per year.

Actual rate:
By mid-October 2025, only five Starship orbital launch attempts had been made, and no further launches were planned for the remainder of 2025.

Future goal:
SpaceX aims for a launch rate of up to 48 per year (one launch per week), potentially starting in April 2026, contingent on resolving technical issues and achieving full reusability.