Table of Contents
What is the vapor compression process?
Vapor-compression uses a circulating liquid refrigerant as the medium which absorbs and removes heat from the space to be cooled and subsequently rejects that heat elsewhere. … That pressure reduction results in the adiabatic flash evaporation of a part of the liquid refrigerant.
What is thermal vapor compression?
2.2. For vapor compression, the feed, after passing through a heat exchanger, is converted to vapor and then compressed by mechanical or thermal means. The compressed vapor, as fresh water, has high temperature and pressure and is circulated through the initial heat exchanger to heat the incoming feed.
How does MVR evaporator work?
MVR evaporators operate on a heat pump principle. The evaporated water vapor is recompressed with a simple, low-speed centrifugal fan or compressor which increases the saturation temperature of the vapor. After the fan, vapor can be used as heating steam in the same unit.
How does a multi effect still work?
Multiple-effect distillation (MED) desalination is a process that includes multiple effects. The feed water is heated in tubes with steam in each effect, usually by spraying saline water on them. Portion of the water evaporates, and afterward the steam enters the tubes of the next effect.
What is solar distillation system?
Solar distillation is a process in which the energy of the sun is directly used to evaporate freshwater from sea or brackish water. The process has been used for many years, usually for small-scale applications. … The passive solar stills use solar energy as the only source of thermal energy.
What is function of compressor in Vapour compression system?
The compressor compresses the refrigerant to a high-pressure vapor, causing it to become superheated. Once the refrigerant is compressed and heated, it leaves the compressor and enters the next stage of the cycle.
Which refrigerant is used in Vapour compression cycle?
The most common include ammonia, Freon (and other chlorofluorocarbon refrigerants, aka CFCs), and HFC-134a (a non-toxic hydrofluorocarbon). The Vapor-Compression Refrigeration Cycle is comprised of four steps.
What is refrigeration effect?
Refrigerating Effect. This is the heat absorbed in the evaporator per lb of refrigerant. It is determined by the difference in enthalpy of a lb or refrigerant vapor leaving the evaporator and that of a lb of liquid just upstream (ahead) of the expansion valve at the evaporator.
What is steam TVR?
Thermal Vapor Recompression (TVR) normally takes place across one or more stages by utilizing medium or high pressure steam in an ejector which recycle a portion of the vapor from the vapor separator and mixing it with the steam. … The steam consumption for a TVR evaporator will vary between approx.
What is TVR in boiler?
The thermal vapor recompression (TVR) builds on the same principle as the mechanical alternative, but uses only a portion of the resulting vapor for heating the system. … A certain amount of steam, the so-called motive steam, is required for the operation of a thermal vapor compressor.
How does multi stage flash distillation work?
The multi-stage flash distillation is a process where incoming seawater is pumped to a higher pressure and heated to near boiling. Through a series of stages, the seawater pressure is decreased to generate vapor that is condensed by the incoming seawater.
What is MVR system?
Mechanical vapor recompression (MVR) is an energy recovery process which can be used to recycle waste heat to improve efficiency. Typically, the compressed vapor is fed back to help heat the mother liquor in order to produce more vapor or steam.
What is an MR evaporator?
What is MEE plant?
Multi Effect Evaporator [MEE] Multi Effect Evaporator is defined as a apparatus for efficiently using the heat from steam to evaporate water. In a multiple-effect evaporator, water is heated in a sequence of vessels, each held at a lower pressure than the last. … Types of industrial evaporators: Falling Film Evaporator.
What is multi effect and vapour compression distillation?
Multi-Effect Distillation (MED) is a thermal desalination technology that produces distilled quality water directly from seawater by using low / medium pressure steam and electricity. With the use of a Thermo Vapour Compressor along with MED, the technology is named MED-TVC.
What are the disadvantages of multistage flash distillation?
Disadvantages of a multi-stage flash distillation system are a high operating cost when waste heat is not available for the distillation process and relatively high rates of corrosion and scale formation due to high operating temperatures.
What is the difference between MSF and MED?
In a MED plant, evaporation is from a seawater film in contact with the heat transfer surface, whereas in the MSF plant only convective heating of seawater occurs within the tubes and evaporation is from a flow of brine flashing in each stage to produce vapour.
Who created the solar still?
Charles Wilson In 1882 Charles Wilson invented the first modern conventional still a massive solar still plant which was used to supply fresh water to a mining community in northern Chile.
Who discovered the solar still?
The roots of modern solar power can be traced back to 1839. It was at this time that a 19 year old French physicist, A.E.Becquerel, whose focus up to that point had been related to phosphorescence and luminescence, discovered the photovoltaic effect.
Is evaporated water distilled?
As water evaporates, it distills, or leaves the salt behind. The pure evaporated water is collected and condensed to form distilled water.
What is the difference between VCRS and VARS?
Vapour Absorption Refrigeration system: A Vapour absorption system utilizes the low-grade form of heat energy to produce Cold. Whereas the VCR system needs work energy to produce cold which is a high-grade form of energy and expensive to produce.
What is ideal Vapour compression cycle?
In an ideal vapor-compression refrigeration cycle, the refrigerant enters the compressor as a saturated vapor and is cooled to the saturated liquid state in the condenser. It is then throttled to the evaporator pressure and vaporizes as it absorbs heat from the refrigerated space.
Why refrigerant is compressed?
To cool a room down, you need to collect the heat and dump it somewhere else. The air in this somewhere else must be a lower temperature than the refrigerant for you to be able to dump the heat. To make sure this is possible, the refrigerant is compressed so that the temperature increases.
What does R22 stand for?
R22 is the short name for the halocarbon compound CHClF2 (monochlorodifluoromethane), which is used as the refrigerant. R stands for the refrigerant. In the number 22 second 2 denotes the number of the fluorine atoms in the compound. The boiling point of R22 is -40.8 degree Celsius (-41.4 degree F).
What is unit of refrigeration?
The unit of refrigeration is expressed in terms of ton of refrigeration (TR). One ton of refrigeration is defined as the amount of refrigeration effect (heat transfer rate) produced during uniform melting of one ton (1000kg) of ice at 0C to the water at the 0C in 24 hours.
What are the four 4 stages of vapor compression refrigeration cycle?
The Vapor Compression Refrigeration Cycle involves four components: compressor, condenser, expansion valve/throttle valve and evaporator. It is a compression process, whose aim is to raise the refrigerant pressure, as it flows from an evaporator.
What is refrigerant capacity?
Cooling capacity is the measure of a cooling system’s ability to remove heat. It is equivalent to the heat supplied to the evaporator/boiler part of the refrigeration cycle and may be called the rate of refrigeration or refrigeration capacity.
What is load in refrigeration?
Cooling load is defined as the average rate at which the heat is removing from the cold space by refrigeration equipment. Similar to the unit of refrigeration it is also expressed in Ton of refrigeration (TR). … Heat emitted by the people occupied in refrigerated space/ objects whose temperature is to be lowered.
Is refrigerant gas or liquid?
A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again.