what is the difference between refrigerators and heat pumps?
415115
good question. refrigerators eject heat with work input. but heat pumps gives heat with work input.\n example. we use a normal refrigerators for cooling our food stuffs. but usually in cold countries they use a heat pump in the hall or in the bed room for heating up the room at the desired temperature to keep the room warm enough. both works on same principle but action are different.
473977
deliberate. AC uses same principle as the refridgerator, so after the fridges caught on, it was only a matter of time till somebody found a new use for technology.
836069
Cold falls so the cold created in the freezer helps to keep the fridge part cool also.\n\nCoach
330377
It was hard to obtain even this information (ref. 1) on the web. Apparently lithium absorption technology is quite similar to that using ammonia which has several useful web descriptions (e.g., ref. 2). Both types use a heat source to operate, and have a complicated means of condensing and circulating refrigerant. Following is an earlier answer I gave to a question on absorption refrigerators which deals with the ammonia type:\nThere are two types of these refrigerators.  One operates in a "batch" like cycle having a generation phase and a refrigeration phase, with a check valve to ensure unidirectional flow.  The other system operates in a continuous cycle, has no moving parts and still achieves unidirectional flow in an intriguing way. \nBoth types use heat to drive the ammonia gas out of its water solution at one point in the loop, pass the gas through a condenser and an evaporator, and redissolve it at another point.\nIn the two-phase system the generation phase drives the ammonia out of solution, and the ammonia cools, condenses and flows through the check valve into a receiver.  The refrigeration phase removes the heat which reduces system pressure, allowing the liquid ammonia to evaporate, cool the refrigerator, and be reabsorbed by the water.\nThe continuous cycle performs the same operations concurrently in a similar loop without a check valve and with constant pressure throughout the loop.  What enables the refrigerant to circulate is the addition of hydrogen gas into the ammonia gas in the evaporator and the gaseous space of the absorber which follows the evaporator.  In the words of ref. 2, each of the two gases in the evaporator, according to Dalton's law, "behaves as if it occupies the space alone. [...] Total pressure in the system is the sum of the vapor pressure of the ammonia plus the hydrogen pressure.  When the pressure of the ammonia vapor is below the pressure corresponding to the vapor pressure for ammonia alone, the ammonia continues to evaporate. It tries to reach a vapor pressure corresponding to the temperature in the absorber."\nNote that the flow of the ammonia keeps the hydrogen in the evaporator and absorber and out of the condenser.  What the quote above means is that flow occurs because both the condensation and the subsequent evaporation of the ammonia occur at nearly the same temperature and at just the same total pressure.  How is this possible?  Because the ammonia pressure is 100% of the pressure in the condenser but a smaller percentage of that same pressure when in the evaporator due to the added hydrogen.  This creates a continuous movement of the ammonia around the loop!  The diagram in the ref. 2 page clarifies this and provides many practical details omitted from this description.\nEDIT: Found another page with good comparison between ammonia and lithium bromide systems with diagrams, ref. 3.
1049759
mechanical engineers deals with machines to be more precise the moving parts of any machine while electrical engineers deal with the electrical circuitry o any machine. for example the gears of any machine will be under the purview of mechanical engineers while all the electrical on off switches are dealt by electrical engineers. In an air conditioner , the compressor willl be designed by mechanical engineers while electrical engineers wil design the temparature control circuits.
333197
Yes, there is.  It's a silicon chip that becomes cold on one side and hot on the other.  However, they use a lot of energy compared to environ compressors.
370121
an air conditioner helps to maintain the room at  ambient conditions suitable for human comfort by monitoring the parameters like humidity,temperature,dust etc where as a refrigerator keeps the temperature within the system lower than that of the surroundings by using 2nd law of thermodynamics.
301581
It is not a pump like a centrifugal or axial pump that we used to transfer fluids but actually we used the term HEAT PUMP to a system which transfer heat from a low temperature reservoir to a hot temperature reservoir through supply of work. It consists of component such as condenser, compressor, expansion valve and evaporator. \n\nThere are several types of heat pump system such as gas compression heat pump and phase change heat pump. \n\nApplication of heat pump can be found normally in domestic air-conditioning system. In a four seasons country the system normally has a valve that can "switch" to become a heater or cooler by reversing the flow of refrigerant.
271632
A heat engine typically uses energy provided in the form of heat to do work and then exhausts the heat which cannot be used to do work. Thermodynamics is the study of the relationships between heat and work. The first law and second law of thermodynamics constrain the operation of a heat engine. The first law is the application of conservation of energy to the system, and the second sets limits on the possible efficiency of the machine and determines the direction of energy flow. \nHeat engines are typically illustrated on a PV diagram  Heat engines such as automobile engines operate in a cyclic manner, adding energy in the form of heat in one part of the cycle and using that energy to do useful work in another part of the cycle.
687659
Multistage cryocoolers are used by nasa to keep sensors and chips mighty cold.  Supercomputers also need cooling and this type of cooler is used today as it is much cheaper than the older option, liquid helium, which required massive gas cryogenic compression tanks to keep cold.\n\nRead up on stage cryocoolers and adiabatic demagnetization refrigerators (these can go below 4K).
225345
All of them acts in cools the air in a household refrigerator, refrigerant gas (e,g Freon, ammonia,..etc) compressed through compressor and evaporated , and during that circle air cools and heat transfer occur.
167294
In refrigerator, there is a fluid gas (previously CFC). this fluid is compressed to become higly compressed gas. this gas is then passed through condenser which converts this gas into liquid. Now the pressure on working liquid is so adjusted (using capillary tubes) so that the boiling point of this liquid is lower than our desiered temperature. This liquid is then passed through evaporator (which is placed inside the refrigerator) this liquid absorbs heat from air within and evaporates which in turn passes through compressor thus completing the cycle.
530322
I agree with the above answer. But I think you will find that freezing damages batteries. It is the refrigerator that extends life. But it does not increase the amount of energy in the battery. It only extends shelf life. That is because all batteries slowly self discharge while sitting on the shelf, so that after a few years, even though you never used them, they are dead. The cooler the temperature the slower they self discharge.
377342
compressor: compresses things\nevaporator: evaporates things\ncondensor: condenses things\nmetering device: meters things\n\ngood luck
380730
The basis of most (more than 95%) refrigeration systems is the ' vapour compression cycle". The media (vapour) is Refrigerant (hydrochlorofluorocarbons - HCFC or hydrofluorocarbons - HFC) or freon which is non-toxic, non-explosive and non-corrosive. These Refrigerants have a boiling point of aprox. Minus 40°C which means that even if the air (outside or inside) temperature is as low as minus 39°C it still has heat to be absorbed by refrigerants. \n\nThe vapour compression cycle requires four components:\n\n1) The compressor: To raise the pressure of low-pressure low temperature gas to high-pressure high temperature gas. There are many types of compressors; the most common are Reciprocating, Rotary, Scroll, Screw and Centrifugal. \n2) The Condenser: To change the state of high-pressure, high temperature gas to high-pressure, high temperature LIQUID. This is achieved by passing ambient air (known as air-cooled) or water (known as water-cooled) over the condenser tubes. \n3) The Expansion Device: The purpose of the device is to change the state of the refrigerant from high-pressure, high temperature liquid to low pressure low temperature saturated liquid. This is achieved by passing the liquid through an orifice. \n4) The Evaporator: To absorb the heat from room air or water, which in the case of a chiller is circulated around the evaporator coil. This will change the state of low-pressure, low temperature saturated liquid to low pressure, low/medium temperature gas. \nThese components are common to the vast majority of domestic refrigerators and appear in slightly different forms in 95% of air conditioning and refrigeration systems, Domestic, commercial or industrial. This vapour compression cycle if reversed (condenser becomes evaporator and visa versa) can now absorb heat from outside and transfer it to inside, hence saving energy. This is called Reverse Cycle Heat Pump. Energy savings can be as high as 4 to 1 (for every kW input we get 4 kW output).
1037873
Depends on what you mean by types.\n\nDo you mean the type of material used in constuction or the type of activity the building is intended for.\n\nMost large building use a chilled water system where they use chillers to cool water down to about 42 deg F then pump the water throught the building to air handler units which blow air across the coils filled with the water.  This heats the water, but cools the air.  As the air is circulated throughout the area the water is returned to the chiller to be recooled and the process starts all over again.\n\nHowever, an important point is capacity.  That will be determined by both what the intended use of the building is and what sort of material is used.
834930
I answered your previous post....  It seems like you don't understand the process of evaporation (turning from liquid to gas).  For example:\nAt 100 degreesC, water can be a gas, a liquid, or both.  However, as a gas at 100C, water vapor contains more energy than liquid water at 100C.  The process of evaporation (turning liquid into gas) requires energy that is not registered as an increase in temperature.  Each change in state (solid to liquid, liquid to gas) requires and "extra boost" of energy not registered as temperature to the material changing states. (Also think about ice water...)\nSo, when the the compressed liquid refrigerant is allowed to expand and turn into gas (evaporation) the surrounding energy within the refrigerator "boils" the the refrigerant giving the refrigerant the energy to turn into a gas...\nThis whole process would not be possible without the compressor.\nThe refrigerant gas, normally pure ammonia, boils at       -27C @ ambient pressure.  But through compression it is turned into liquid at room temp.  But when it is allowed to expand in the coils within the refrigerator it quickly boils turning into a gas "absorbing" the required energy from interior of the refrigerator....  So, if some how the inside of the refrigerator was -30C the liquid ammonia would fail to turn into a gas and the liquid amonia would actually be warming the interior since it was initially a liquid at room temp....