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Climate Control
Heating, ventilation, and air conditioning (HVAC ) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation as HVAC&R or HVACR, or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers). HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels, and senior living facilities; medium to large industrial and office buildings such as skyscrapers and hospitals; vehicles such as cars, trains, airplanes, ships and submarines; and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASHRAE Handbook
The ASHRAE Handbook is the four-volume flagship publication of the nonprofit technical organization ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers). This Handbook is considered the most comprehensive and authoritative repository of practical knowledge on the various topics that form the field of heating, ventilation, air-conditioning, and refrigeration ( HVAC&R). The four volumes are ''Fundamentals'', ''Refrigeration'', ''HVAC Applications'' ("Applications"), and ''HVAC Systems and Equipment'' ("Systems and Equipment"). Members of ASHRAE receive the current volume, in both print and CD-ROM form, each year as a basic membership benefit. An enhanced electronic version, known as ''ASHRAE Handbook Online'' is a web-based version updated annually that contains the four latest volumes as well as extra content such as calculations, demonstration videos, and spreadsheets. The various versions of the Handbook are typically available to the public v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nikolay Lvov
Nikolay Aleksandrovich Lvov (; May 4, 1753 – December 21, 1803) was a Russian Empire, Russian artist of the Age of Enlightenment. Lvov, an amateur of noble lineage, was a polymathBohlman, p. 45. who contributed to geology, history, graphic arts and poetry, but is known primarily as an architect and ethnography, ethnographer, compiler of the first significant collection of Russian folk songs (the Lvov-Prach collection). Lvov's architecture represented the second, "strict" generation of neoclassical architecture, neoclassicism stylistically close to Giacomo Quarenghi.Shuisky, p. 128. Lvov worked in Saint Petersburg but his best works survived in the countryside, especially his native Tver Oblast, Tver Governorate. He redesigned the external appearance of Peter and Paul Fortress and created an unprecedented Trinity Church combining a Roman architecture, Roman rotunda (architecture), rotunda with one-of-a-kind pyramidal bell tower. He adapted rammed earth technology to the environmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seasonal Thermal Energy Storage
Seasonal thermal energy storage (STES), also known as inter-seasonal thermal energy storage,is the storage of heat or cold for periods of up to several months. The thermal energy can be collected whenever it is available and be used whenever needed, such as in the opposing season. For example, heat from solar collectors or waste heat from air conditioning equipment can be gathered in hot months for space heating use when needed, including during winter months. Waste heat from industrial process can similarly be stored and be used much lateror the natural cold of winter air can be stored for summertime air conditioning. STES stores can serve district heating systems, as well as single buildings or complexes. Among seasonal storages used for heating, the design peak annual temperatures generally are in the range of , and the temperature difference occurring in the storage over the course of a year can be several tens of degrees. Some systems use a heat pump to help charge and discha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Cooling
Free cooling is an economical method of using low external air temperatures to assist in chilling water, which can then be used for industrial processes, or air conditioning systems. The chilled water can either be used immediately or be stored for the short- or long-term. When outdoor temperatures are lower relative to indoor temperatures, this system utilizes the cool outdoor air as a free cooling source. In this manner, the system replaces the chiller in traditional air conditioning systems while achieving the same cooling result. Such systems can be made for single buildings or district cooling networks. Operation For a human-powered version, see yakhchal. When the ambient air temperature drops to a set temperature, a modulating valve allows all or part of the chilled water to by-pass an existing chiller and run through the free cooling system, which uses less power and uses the lower ambient air temperature to cool the water in the system. This can be achieved by installing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Cooling
Deep water source cooling (DWSC) or deep water air cooling is a form of air cooling for process and comfort space cooling which uses a large body of naturally cold water as a heat sink. It uses water at 4 to 10 degrees Celsius drawn from deep areas within lakes, oceans, aquifers or rivers, which is pumped through the one side of a heat exchanger. On the other side of the heat exchanger, cooled water is produced. Basic concept Water is most dense at at standard atmospheric pressure (not true for seawater). Thus as water cools below 3.98 °C it increases in density and will settle below. As the temperature climbs above 3.98 °C, water density also decreases and causes the water to rise, which is why lakes are warmer on the surface during the summer. The combination of these two effects means that the bottom of most deep bodies of water located well away from the equatorial regions is at a constant 3.98 °C. Air conditioners are heat pumps. During the summer, when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renewable Energy
Renewable energy (also called green energy) is energy made from renewable resource, renewable natural resources that are replenished on a human lifetime, human timescale. The most widely used renewable energy types are solar energy, wind power, and hydropower. Bioenergy and geothermal power are also significant in some countries. Some also consider Nuclear power proposed as renewable energy, nuclear power a renewable power source, although this is controversial, as nuclear energy requires mining uranium, a nonrenewable resource. Renewable energy installations can be large or small and are suited for both urban and rural areas. Renewable energy is often deployed together with further electrification. This has several benefits: electricity can heat pump, move heat and Electric vehicle, vehicles efficiently and is clean at the point of consumption. Variable renewable energy sources are those that have a fluctuating nature, such as wind power and solar power. In contrast, ''contro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
District Cooling
A district is a type of administrative division that in some countries is managed by the local government. Across the world, areas known as "districts" vary greatly in size, spanning regions or counties, several municipalities, subdivisions of municipalities, school district, or political district. Etymology The word "district" in English is a loan word from French. It comes from Medieval Latin districtus–"exercising of justice, restraining of offenders". The earliest known English-language usage dates to 1611, in the work of lexicographer Randle Cotgrave. By country or territory Afghanistan In Afghanistan, a district ( Persian ) is a subdivision of a province. There are almost 400 districts in the country. Australia Electoral districts are used in state elections. Districts were also used in several states as cadastral units for land titles. Some were used as squatting districts. New South Wales had several different types of districts used in the 21st cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 heater, space heating and water heating. The heat is often obtained from a cogeneration plant burning fossil fuels or biomass, but heating plant, 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) 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 Drawdown (climate), Project Drawdown's 100 solutions to climate change, global warming. His ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Aerospace Defense Command
North American Aerospace Defense Command (NORAD ; , CDAAN), known until March 1981 as the North American Air Defense Command, is a Combined operations, combined organization of the United States and Canada that provides aerospace warning, air sovereignty, and protection for Canada and the continental United States. Headquarters for NORAD and the NORAD/United States Northern Command (USNORTHCOM) center are located at Peterson Space Force Base in El Paso County, Colorado, El Paso County, near Colorado Springs, Colorado. The nearby Cheyenne Mountain Complex has the Alternate Command Center. The Commander of the North American Aerospace Defense Command, NORAD commander and deputy commander are, respectively, a General (United States), United States four-star general or equivalent and a Lieutenant-general (Canada), Canadian lieutenant-general or equivalent. Command NORAD is headed by its Commander of NORAD, commander, who is a Four-star rank, four-star General (United States), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Building Engineering
Architectural engineering or architecture engineering, also known as building engineering, is a Academic discipline, discipline that deals with the engineering and construction of buildings, such as environmental, structural, mechanical, electrical, computational, embeddable, and other research domains. It is related to Architecture, Mechatronics Engineering, Computer engineering, Computer Engineering, Aerospace engineering, Aerospace Engineering, and civil engineering, Civil Engineering, but distinguished from Interior design, Interior Design and architectural design, Architectural Design as an art and science of designing infrastructure through these various engineering disciplines, from which properly align with many related surrounding engineering advancements. From reduction of greenhouse gas emissions to the construction of resilient buildings, architectural engineers are at the forefront of addressing several major challenges of the 21st century. They apply the latest scie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HVAC Control System
HVAC (Heating, Ventilation and Air Conditioning) equipment needs a control system to regulate the operation of a heating and/or air conditioning system. Usually a sensing device is used to compare the actual state (e.g. temperature) with a target state. Then the control system draws a conclusion what action has to be taken (e.g. start the blower). Direct digital control Central controllers and most terminal unit controllers are programmable, meaning the direct digital control program code may be customized for the intended use. The program features include time schedules, set points, controllers, logic, timers, trend logs, and alarms. The unit controllers typically have analog and digital inputs that allow measurement of the variable (temperature, humidity, or pressure) and analog and digital outputs for control of the transport medium (hot/cold water and/or steam). Digital inputs are typically (dry) contacts from a control device, and analog inputs are typically a voltage or cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
