RU2183802C1 - Method of generation of cold and heat in ecologically pure refrigerating plant and increase of refrigerating and heating coefficients - Google Patents

Abstract

FIELD: power engineering; transport, aviation and space engineering where generation of cold and heat is required. SUBSTANCE: proposed method consists in generation of cold and heat in ecologically pure gas- operated refrigerating plant through multi-stage expansion, heating, compression and cooling of cooling agent of main reverse thermal cycle working in closed circuit and generation of additional cold by means of auxiliary reverse thermal cycle working in closed or open circuit; operation in main cycle is ensure by operation of turbine-expander of auxiliary reverse thermal cycle; stage heating of cooling agent of main reverse thermal cycle between expansion stages is effected by removal of heat from cold source; stage cooling of cooling agent between compression stages of main reverse thermal cycle is effected by partial removal of heat to hot source and partially, at temperatures below hot source temperature, by removal of heat from cooling agent of main reverse thermal cycle to cooling agent of auxiliary reverse thermal cycle due to additional cold generated in auxiliary cycle. At two-stage expansion and compression, refrigerating factor in first approximation increases from ε_in== q_2in/1_c.in to

; heat factor

increases respectively; three-stage expansion and compression, refrigerating factor increases from ε_in= q_2ic/1_c.in to

and heating factor

Description

 The invention is intended for use in the field of energy, transport, aviation and astronautics, where cold and heat are required.

A known method of producing cold using refrigeration units operating in the reverse heat cycle. In the reverse cycle, the work of compression L _k exceeds the work of expansion L _t, and due to the summed work L _c, heat Q ₂ is taken from the cold source, and heat Q _l is given to the hot source (respectively 1 kg of working medium l _k , l _t , 1 _c , q ₂ , q ₁ ). Work L _{C is} supplied from any external engine. To characterize the efficiency of the refrigeration unit, the so-called refrigeration coefficient ε is used, defined as follows:
ε = q ₂ / l _c ,
and the heating coefficient ε _heat = ε + 1 (see Kirillin V.A., Sychev V.V., Sheindlin A. E. Technical thermodynamics. - M .: Energia, 1974, p. 370-371, 392).

- Common disadvantages of refrigeration units are:
-low values of refrigeration, heating factors;
- toxicity of refrigerants;
- violation of the ecology of the environment, etc.

A known method of producing cold and heat using a gas (air) refrigeration unit. The cycle of this refrigeration unit in T, s = diagram is shown in FIG. 4. The refrigerant - gas (air) - expands in the expander from pressure p ₁ to pressure p ₂ , performing the work given by the expander to an external consumer (for example, by generating electricity using an electric generator connected to the expander). Air cooled as a result of the adiabatic expansion process in the expander from temperature T _l to temperature T ₂ enters the cooled volume from which it draws heat. The process of heat transfer from the cooled volume to the air occurs at a constant air pressure (p ₂ = const). Heat removal from the cooled volume is possible only if the air temperature during the entire isobaric process of heat extraction is less than the temperature of the cooled volume. In principle, the air temperature at the outlet of the cooled volume T ₃ can be equal to the temperature of the cooled bodies, but in practice it is always lower than this temperature.

From the cooled volume, air is directed to a compressor (turbocharger), where its pressure rises from p ₂ to p ₁ (while the air temperature rises from T ₃ to T ₄ ). Compressed air enters the cooler-heat exchanger. The process in the cooler occurs at a constant air pressure (p ₁ = const).

 The disadvantage of a gas (air) refrigeration unit is the very significant difference between the refrigeration coefficient ε and ε of the Carnot reverse cycle. This is determined by the fact that the processes of heat extraction from the cooled volume and air heat transfer in the cooler are carried out not by the isotherm, but by the isobar. The refrigeration cycle becomes theoretically more efficient in the case of less overcooling of the air leaving the expander, compared with the cooled volume.

 The subcooling of the air leaving the expander depends on the degree of decrease in pressure in the expander turbine, and the lower the degree of decrease in pressure, the theoretically higher the efficiency of the refrigeration cycle. But in this case, the cooling capacity decreases and to ensure it at the same level, it is necessary to increase the air flow in the installation circuit. In addition, the "narrow" cycle is much more affected by the irreversibility of the real processes of adnat compression and expansion in a real installation (see Kirillin V.A., Sychev V.V., Sheindlin A.E. Technical Thermodynamics. - M.: Energy, 1974, p. 373-374).

 A known method of operation of a turbo-refrigerating machine (see SU 524051, class F 25 B 11/00, 11/11/1977) by compressing air in the compressor, which is then cooled in two successively installed heat exchangers and expanded in two stages of the turbine (expander).

 The disadvantage of this method of operation of a turbo-refrigeration machine is not high enough efficiency.

 Of the known methods for producing cold, the closest is the method of producing cold and heat in an environmentally friendly gas refrigeration unit by multi-stage expansion, heating, compression, and cooling of the refrigerant of the first reverse heat cycle (OTC), operating in a closed circuit, and obtaining additional cold using the second OTC, working in a closed or open circuit (see US 4777805 A, CL F 25 B 7 / 00,18.10.1988).

 The disadvantage of this method is the lack of efficiency at sufficiently large temperature zones of cooling and heating due to the strong increase in irreversible heat loss and a decrease in the thermodynamic efficiency of the plant’s operating cycle.

 The technical result to which the present invention is directed is to obtain additional cold and heat and increase refrigeration and heating coefficients in environmentally friendly gas refrigeration units that can work with any gaseous working fluid. In addition, the problem is solved by reducing the freezing of air and a corresponding increase in air flow.

и соответственно увеличивается отопительный коэффициент

при трехступенчатом расширении и сжатии холодильный коэффициент увеличивается с ε_исх= q_{2 исх}/l_{ц исх} до

и соответственно увеличивается отопительный коэффициент

и эти коэффициенты увеличиваются с ростом величины n, а для многоступенчатого охлаждения используется дополнительный холод, полученный во вспомогательном цикле.With two-stage expansion and contraction, the refrigeration coefficient in a first approximation increases from ε _ref = q _{2 ref} / l _{c ref} to

and accordingly the heating coefficient increases

during three-stage expansion and contraction, the refrigeration coefficient increases from ε _ref = q _{2 ref} / l _{c ref} to

and accordingly the heating coefficient increases

and these coefficients increase with increasing n, and for multi-stage cooling, additional cold obtained in the auxiliary cycle is used.

 The technical result is achieved by the fact that in the method of producing cold and heat in an environmentally friendly gas refrigeration unit by multi-stage expansion, heating, compression and cooling of the refrigerant, the total OTC is used, consisting of the main OTC operating in a closed circuit and an auxiliary OTC operating in a closed or open circuit, to obtain additional cold using auxiliary OTC, the work necessary in the main cycle is provided by the operation of the turbine-expander of the auxiliary OTC, steps the first heating of the main OTC refrigerant between the stages of expansion is carried out by heat removal from a cold source, and the stepwise cooling of the refrigerant between the compression stages of the main OTC is carried out by partial heat removal to the hot source and partially at temperatures below the hot source temperature, heat is removed from the main OTC refrigerant to the auxiliary OTC refrigerant after account received additional cold in the auxiliary cycle.

 The technical result is also achieved by the fact that the same refrigerant is used as the refrigerant of the main and auxiliary OTC.

 The technical result is also achieved by the fact that at given temperatures of hot and cold sources and at specified degrees of compression and expansion to increase or decrease the flow of refrigerant in the main and auxiliary OTC, respectively, increase or decrease the pressure of the refrigerant.

 In FIG. 1 shows a schematic diagram of an installation for implementing the proposed method.

 Figure 2 shows the TS diagram of a two-stage cycle of heat and cold production according to the proposed method.

 Figure 3 shows the TS diagram of a three-stage cycle of heat and cold production according to the proposed method.

 4 is a TS diagram of a known cold production cycle.

 The installation for producing cold contains in series connected the first stage of the compressor 1, the heat exchanger 2, the second stage of the compressor 3, the heat exchanger 4, the first stage of the turbine 5, the heat exchanger 6, the second stage of the turbine 7 and the heat exchanger 8 of the main OTC. The shafts of the compressor and turbine stages are combined and connected to the shaft of the auxiliary OTT expander turbine 9, which also includes the compressor 10 and two heat exchangers 11 and 12. It is also possible to use an open auxiliary cycle. Heat exchangers 6 and 8 are located in the cooled volume 13, and heat exchangers 2 and 4 are located in the heated volume 14.

 The method of producing cold is as follows.

In a two-stage process of compression, cooling (see figure 2), the refrigerant of the main OTC expands (adiabat a ₁ -3) in the first expander (in the first turbine) 5 from pressure P _al (P _al = 4) to pressure P ₃ (P ₃ = 2), doing the work given by the expander to the compressor shaft of the main OTC.

The refrigerant of the main OTC, cooled as a result of adiabatic expansion in expander 5 (adiabat a _l -3), enters the heat exchanger 6 of the cooled volume 13, from which it removes heat (isobar 3rd).

The refrigerant of the main OTC expands (adiabat e-r) in the second expander (in the second turbine) 7 from the pressure P _e (P _e = 2) to the pressure Pr (Pr = 1), doing the work given by the expander to the compressor shaft of the main OTC.

The refrigerant of the main OTC, cooled as a result of adiabatic expansion in expander 7 (adiabat e-r), enters the heat exchanger 8 of the cooled volume 13, from which it removes heat (isobar r-a ₃ ).

The refrigerant of the main OTC with a temperature corresponding to point a ₃ is compressed (adiabat a3-d) in the first compressor 1 from a pressure P _a3 (P _a3 = 1) to a pressure P _d (P _d = 2). The compressor receives operation from expanders 5 and 7.

The refrigerant of the main OTC, heated as a result of adiabatic compression in compressor 1 (adiabat a ₃ -e), enters the heat exchangers 2 and 12 and is cooled (isobar d-e), transferring heat partially to the hot source (heat exchanger 2) and partially to the refrigerant cooled in the result of adiabatic expansion, auxiliary OTC (heat exchanger 12).

Refrigerant main OTC at a temperature corresponding to the point e, compressed (adiabatic e-g) in a second compressor 3 of the pressure P _f (P _e = 2) to the pressure P _x (P _x = 4). The compressor receives work from the expanders 5 and 7, and receives the missing work from the expander 9 of the auxiliary OTC.

The refrigerant of the main OTC, heated as a result of adiabatic compression in compressor 3 (adiabat e-g), enters the heat exchanger 4 and is cooled (isobar g- _l ), giving off heat to the hot source.

 The cycle diagram for three-stage processes of compression, cooling, expansion and heating is shown in Fig.3. The order of operations in a three-step process is similar.

 The cycle diagram of the auxiliary OTC is shown in Fig.4.

 The electric motor (heat engine) 15 drives the compressor 10 used in the auxiliary OTTS.

The auxiliary OTC refrigerant is compressed from a pressure of P ₃ (P ₃ = 1) to a pressure of P ₄ (P ₄ = 2) to create π _{to cp} = P ₄ / P ₃ = π _{t cp} required to get the work 1 _{t cf} = 1 _{c main}

 The auxiliary OTC refrigerant heated as a result of adiabatic compression in the compressor 10 (adiabat 3-4) enters the heat exchanger 11 and cools, transferring heat to the hot source of the auxiliary OTC (isobar 4-1).

The auxiliary OTC refrigerant cooled in the heat exchanger 11 to a temperature T _l expands in the expander (turbine) 9 from a pressure P _l (P _l = 2) to a pressure P ₂ (P ₂ = 1) (adiabat 1-2) and is cooled to a temperature T _2, performing the work is equal to 1 _{q DOS} (l _{t i aux} 1 = _core), and giving it to the main compressor shaft OTC.

 The auxiliary OTC refrigerant cooled as a result of adiabatic expansion in the expander 9 (adiabat 1-2) enters the heat exchanger 12 and removes heat (isobar 2-3) from the refrigerant of the main OTC (isobar d-e).

и соответственно увеличивается отопительный коэффициент

при трехступенчатом расширении и сжатии холодильный коэффициент увеличивается с ε_исх= q_{2 исх}/l_{ц исх} до

и соответственно увеличивается отопительный коэффициент

Указанные коэффициенты увеличиваются с ростом величины n.As a result of the implementation of the method of producing cold and heat in an environmentally friendly gas refrigeration unit with two-stage expansion and compression, the refrigeration coefficient in the first approximation increases from ε _ref = q _{2 ref} / l _{c ref} to

and accordingly the heating coefficient increases

during three-stage expansion and contraction, the refrigeration coefficient increases from ε _ref = q _{2 ref} / l _{c ref} to

and accordingly the heating coefficient increases

The indicated coefficients increase with increasing n.

 The method can be used in steam refrigeration units.

Claims (3)

 1. The method of producing cold and heat in an environmentally friendly gas refrigeration unit by multi-stage expansion, heating, compression and cooling of the refrigerant of the first reverse heat cycle (OTC) operating in a closed circuit and obtaining additional cold using a second OTC operating in a closed or open circuit , characterized in that the total OTC is used, consisting of the main OTC operating in a closed circuit and an auxiliary OTC operating in a closed or open circuit; cold with the help of auxiliary OTC, necessary in the main cycle of operation is provided by the operation of the auxiliary OTC expander turbine, the main OTC coolant between the expansion stages is heated by heat removal from a cold source, and the refrigerant is cooled in steps between the main OTC compression stages by partial heat removal to hot to the source and partially, at temperatures below the temperature of the hot spring, heat removal from the refrigerant of the main OTC to the refrigerant of the auxiliary OTC s by obtaining additional cooling in the secondary cycle.  2. The method according to p. 1, characterized in that the same refrigerant is used as the refrigerant of the main and auxiliary OTC.  3. The method according to p. 1, characterized in that at given temperatures of hot and cold sources and at given degrees of compression and expansion to increase or decrease the flow rate of the refrigerant in the main and auxiliary OTC, respectively, increase or decrease the pressure of the refrigerant.

Images