RU2125688C1 - Osmotic absorption heat machine - Google Patents

Abstract

FIELD: refrigerating engineering. SUBSTANCE: spaces of generator and absorber communicate through semipermeable partition made of heat insulating material. Use of proposed invention makes it possible to increase efficiency and reduce power losses for recirculation of cooling agent with absorbent between absorber and generator and dispense with recirculation pumps. EFFECT: reduced noise, simplified design. 1 dwg

Description

 The invention relates to mechanical engineering, namely to refrigeration machines. Known absorption chillers containing a generator, condenser, evaporator, absorber, pipe fittings, pumps, interconnected by pipelines in a single unit. /1. UDC 621.56 Dossat Roy J. Fundamentals of refrigeration. Per. from English M .: Light and food industry, 1984, p. 466.

 2. UDC 620.92 Twidell J., Weir A. Renewable energy sources. Per. from Eng.-M .: Energoatomizdat, 1990, p. 125.

 3. UDC 536.7, 621.036 Nashchokin V.V. Technical thermodynamics and heat transfer. Textbook for non-energy specialties of universities.-M .: "Higher School", 1975, p.303.

 4. UDC 621.1 Thermal Engineering Reference. Ed. 2nd, rev. Ed. V.N. Yureneva and P.D. Lebedev. T.1-M. "Energy", 1975, p. 286.

5. PCT Application N 89/11071, Cl. F 25 B 15/14, 1989. Osmotic heat engine. /
These chillers use the property of certain liquids / absorbents / to absorb other liquids / refrigerants /, which are relatively low boiling.

 The disadvantages of the device include: low efficiency, the presence of mechanical rubbing parts, namely in pumps for recirculating a refrigerant solution with an absorbent between the absorber and the generator, the complexity of the device and regulation, and the presence of some noise, albeit small compared to compressor refrigeration machines.

 The closest in technical essence is an osmotic heat engine containing an absorber, generator, condenser, a throttle device, an evaporator and a semi-permeable baffle that passes refrigerant vapor and traps absorbent and located between the evaporator and the absorber, all devices are interconnected by pipelines in which the refrigerant circulates , absorbent or their solution / PCT Application N89 / 11071, cl. F 25 B 15/14, 1989. Osmotic heat engine.

 However, this heat engine, by the principle of operation, differs little from conventional absorption machines and, like all absorption machines, uses bar-gradient diffusion caused by the pressure gradient of the saturated vapor of the refrigerant over the pure liquid refrigerant / evaporator / and over its solution in the absorbent / absorber / . In this case, the semi-permeable partition only allows the absorber to be positioned above the evaporator.

 Instead of the commonly used pump for recirculating the refrigerant and absorbent solution between the absorber and the generator, the gravitational circulation principle is used due to the difference in densities of the weak and concentrated solution. This is a disadvantage of the known engine, since it cannot work in the absence of gravity, for example in space.

 In addition, the specified engine, called osmotic, in fact is not, based on the definition of the osmosis process.

 The purpose of the invention is to increase the efficiency and reduce energy losses for recirculation of the refrigerant solution with the absorbent between the absorber and the generator, the exclusion of mechanical rubbing parts and recirculation pumps, noise reduction, simplification of design, the rejection of the use of electricity.

 The goal is achieved in that the internal cavities of the generator and the absorber are made communicating with each other, but at the same time they are separated by a semi-permeable, heat-insulating partition / membrane, hollow fibers, etc. /, which allows the refrigerant to pass through and retain the absorbent.

 The invention is illustrated in the drawing, which shows schematically a General view of the refrigeration machine.

 The chiller contains the following main components: on the high pressure side - generator 1, compensator 2; on the low pressure side, an evaporator 3, an absorber 4 connected by pipelines 5, a semi-permeable partition 6 separating the internal cavities of the generator 1 and absorber 4, while the generator 1 and the absorber 4 are interconnected through this partition 6, as well as coolant and cooling water pipelines / conventionally not shown in the diagram /. The partition 6 has the ability to pass the refrigerant and retain the absorbent, while it also has thermal insulation properties.

 The working substance for the implementation of the refrigeration cycle of the absorption machine is a solution consisting of two components with different boiling points at the same pressure. One of them with a lower boiling point serves as a refrigerant, and the other as an absorbent.

 The refrigerant flows from condenser 2 to evaporator 3, absorber 4, generator 1 and returns to condenser 2, and the absorbent, unlike a conventional absorption chiller, does not circulate from absorber 4 to generator 1 and vice versa, but is constantly located in generator 1 and absorber 4, but in different concentrations in solution with a refrigerant.

 The circulation of the refrigerant is carried out, in contrast to the traditional absorption refrigeration machine, through the use of the effect of osmosis. Osmosis is a spontaneous process of transition of a solvent through a semipermeable membrane into a solution. If a pure solvent and a solution of a substance in this solvent or two solutions of different concentrations are placed in two compartments, on both sides of a semipermeable partition capable of passing only solvent molecules, the following will be observed in such a system. Due to the difference in pressure / concentration / solvent molecules in different compartments, the transition of the solvent molecules into the volume with their lower concentration, i.e. into the concentrated solution compartment.

 The sequence of the operation of the absorption osmotic machine is as follows. Liquid refrigerant / high pressure / is supplied from the condenser 2 to the evaporator 3, while due to pressure losses during its movement through the pipe 5 / or in the butterfly valve / the pressure of the refrigerant decreases.

 The liquid refrigerant in the evaporator 3 turns into steam, taking heat from the medium to be cooled. The resulting low-pressure steam is piped 5 from the evaporator 3 to the absorber 4, where this vapor is absorbed by the absorbent.

 The refrigerant flows from the evaporator 3 to the absorber 4, since the vapor pressure above the solution in the latter is somewhat lower.

 The pressure of the solution in the absorber 4 determines the pressure and, therefore, the boiling point of the refrigerant in the evaporator 3.

 In turn, the pressure of the solution depends on the properties of the absorbent, its temperature and concentration.

 When the absorbent absorbs vapor of the refrigerant coming from the evaporator 3, the volume of the refrigerant decreases and the heat of absorption is released.

 To maintain the temperature and pressure of the solution at a given level, the heat released in the absorber 4 / is equal to the sum of the latent heat of vaporization and the heat of dissolution of the refrigerant in the absorbent /, is removed to the environment in the condenser 2. This process is carried out as follows.

 The refrigerant vapor absorbed by the absorbent increases the pressure of the solution in the absorbent 4. Therefore, it is necessary to continuously increase the concentration of the absorbent in the solution to maintain its pressure at a sufficiently low level with respect to the pressure in the generator 1. This is necessary to ensure a given pressure and temperature in the evaporator 3. Increase the concentration of absorbent in the solution located in the absorber 4, is carried out by the flow of refrigerant through a semi-permeable partition 6 under the action of osmotic pressure from ab sorber 4 to the generator 1. An increase in the concentration of absorbent in the solution located in the generator 1 is provided by boiling off most of the refrigerant when heated.

 The refrigerant, constantly flowing due to the difference in concentration from the absorber 4 through the partition 6, lowers the concentration of the absorbent, and therefore increases the pressure in the solution located in the generator 1.

 The process takes place without refrigerant compression.

 The refrigerant is separated in the generator 1 from the absorbent when the solution is heated and boils away. The resulting high pressure steam enters the condenser 2, where it is liquefied, giving the latent heat of vaporization to the environment. Then the cycle repeats again.

 This ensures a cycle of the refrigeration machine, which for the implementation of this cycle can use low-grade heat of ventilation exhausts, blowing boilers, solar energy, etc. without the use of electricity.

Claims (1)

 An absorption heat engine comprising an absorber, a generator, a condenser, a throttle device, an evaporator and a semi-permeable baffle that allows refrigerant to pass through and traps absorbent material, all devices being connected by pipelines in which refrigerant, absorbent or their solution circulate, characterized in that the cavity of the generator and the absorber communicate through a semi-permeable partition made of heat-insulating material.