AU2019216253A1 - Enhanced air conditioner using waste heat for fixed or mobile applications - Google Patents

Abstract

There is disclosed an air conditioner for a system having at least one heat source comprising: a working fluid for transferring energy about the system; an ejector for receiving waste heat from exhaust gases of the at least one heat source to heat the working fluid; a vapour generator for converting the working fluid from a liquid to a vapour; a condenser for removing heat from the working fluid to convert the working fluid from a vapour to a liquid; and a receiver for accumulating working fluid during load variation of the system; wherein, the vapour generator comprises a pressure amplifier and the working fluid is delivered to the vapour generator from the ejector to provide a prolonged supply of working fluid without pressure drop and the working fluid is delivered by pressure pulses which are correlated with a chosen boiling temperature of between 5-10°c and with a pressure difference of between 0.01-0.04 MPa, such that the heat transfer from the waste heat of the exhaust gases to the working fluid is performed in the vapour generator by boiling the working fluid whereby phase conversion of the working fluid from liquid to gas causes the most effective heat absorption.

Description

ENHANCED AIR CONDITIONER USING WASTE HEAT FOR FIXED OR MOBILE APPLICATIONS

RELATED APPLICATIONS

The present invention claims priority from Australian provisional patent application no. 2018902935, filed 10 August 2018, the entire contents of which are incorporated herein by reference.

FIELD OF INVENTION

The present invention relates generally to the field of air conditioning and more particularly to stationary or mobile air conditioning systems, in particular, automotive air conditioning systems. The present invention also relates to ejector conditioner systems that use waste heat from the exhaust gases of internal combustion engines, or similar heat sources, to create the refrigerated cycle. The invention relates to an air conditioner that enables a reduction in the fuel consumption of the internal combustion engine or similar heat source by as much as 10-30%.

BACKGROUND OF THE INVENTION

Refrigeration systems are known that operate as ejector conditioner systems in vehicles. Such systems are air conditioners that use the ejected exhaust gases from an internal combustion engine to generate a refrigeration cycle. Due to the common use of internal combustion engines on vehicles, such air conditioning systems are more commonly found in automotive transport applications but can be found in static air conditioning systems which employ an internal combustion engine, such as a generator or the like.

Whilst such ejector conditioner systems have proven effective, they do suffer from a number of drawbacks. Most such systems require a hermetic pump for liquid refrigerant supply from a condenser to a vapour generator. As liquid refrigerant in the vapour generator is heated to boiling temperature, considerably high pressure is created inside the vapour generator. This pressure is typically twice as much as the pressure in the condenser. By way of example, for an accepted condensation temperature equal to 50°C for the refrigerant “R-134a” (maximum accepted ambient temperature is equal to 42°C) pressure in the liquid refrigerant is equal to 13.2 bars. However, in order to heat the liquid refrigerant to boiling temperature, the temperature of the vapour generator needs to be around 80°C, at such a temperature the pressure will be 26 bars, i.e. twice more

2019216253 12 Aug 2019 than it is after a condenser. As a result, the hermetic pumps used in such systems require a complex design to accommodate such pressures. Such hermetic pumps are electric-driven and require a special device for start-up and slowdown and maintenance work. This results in a device that is complicated and expensive.

Further, in existing refrigeration systems for performing refrigeration cycle (boiling of the refrigerant in an evaporator under low pressure), the pressure of the refrigerant should be reduced by an expansion valve. As a result, the need for such a valve lowers cold-productivity and increases the cycle work. As the boiling temperature changes with load variation, an additional area of the io condenser and the evaporator is required thereby increasing metal consumption within the system.

Thus, existing vapour generators generally suffer from having low efficiency and high hydraulic resistance and the overall system is generally too complicated for manufacturing. Further to this, existing ejector conditioner systems have a is low heat transfer coefficient and so they have large overall dimensions.

Connection between the vapor generator load (vapor generator pressure) and pressure in the condenser (condensation pressure) is generally absent, as is any matching between the vapor generator load and the evaporator.

This, there is a need to provide an ejector refrigeration system for air 20 conditioning applications that overcomes the need for a hermetic pump or liquid refrigerant transfer and obviates the requirement for an expansion valve. There is also a need to provide a more efficient ejector system that uses high efficiency vapour generators and heat exchangers. And which is more highly adaptable for manufacturing.

The above references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. In particular, the above prior art discussion does not relate to what is commonly or well known by the person skilled in the art, but assists in the understanding of the inventive step of the 30 present invention of which the identification of pertinent prior art proposals is but one part.

STATEMENT OF INVENTION

The invention according to one or more aspects is as defined in the independent claims. Some optional and/or preferred features of the invention are defined in 35 the dependent claims.

2019216253 12 Aug 2019

Accordingly, in one aspect of the invention there is provided an air conditioner for a system having at least one heat source comprising: a working fluid for transferring energy about the system; an ejector for receiving waste heat from exhaust gases of the at least one heat source to heat the working fluid; a vapour 5 generator for converting the working fluid from a liquid to a vapour; a condenser for removing heat from the working fluid to convert the working fluid from a vapour to a liquid; and a receiver for accumulating working fluid during load variation of the system; wherein, the vapour generator comprises a pressure amplifier and the working fluid is delivered to the vapour generator from the io ejector to provide a prolonged supply of working fluid without pressure drop and the working fluid is delivered by pressure pulses which are correlated with a chosen boiling temperature of between 5-10°c and with a pressure difference of between 0.01-0.04 MPa, such that the heat transfer from the waste heat of the exhaust gases to the working fluid is performed in the vapour generator by is boiling the working fluid whereby phase conversion of the working fluid from liquid to gas causes the most effective heat absorption.

The pressure amplifier comprises a case having cylindrical spaces formed therein, the cylindrical spaces have two different diameters extending along their length and in these spaces two cylinders with corresponding different diameters are 20 located, inlet and outlet orifices are provided in walls of the spaces with each having a spring-and-ball stop valves controlling the opening and closing of the orifices, the stop valves being controllable such that during motion of the cylinders the vapour spaces are in turn connected with to increase the pressure from condensation pressure of around 1.35 MPa for condensation pressure of the 25 working fluid of around 50°C to a vapour generator pressure of around 2.6 MPa for a vapour temperature equal to around 80°C.

The heat source may be an internal combustion engine.

The vapour generator is formed as an integral unit from materials of high heat conductivity, or aluminium alloys.

The integral unit has a solid case and is a heat accumulator having a channel formed in its centre for the exhaust products and a flow rectifier is located in the central channel and at a bottom of the case there is a receiver for receiving the liquid working fluid.

A cover is provided that also has free space that serves as a super-heater and a 35 ratio of liquid and vapour volumes of the working fluid is equal to 1/3 to 2/3 and the case has two rows of channels formed along its perimeter to form an inner

2019216253 12 Aug 2019 and outer channel, wherein the inner channel has inserts where film boiling occurs and outer channel operates as a heat exchanger; in addition, in the case there are channels which connect the vapour space with the pressure amplifier and control instruments.

The flow rectifier has rod fairing with uniformly located plates that provide reliable contact with an outer surface of the orifice, the plates having a length not less than the length of the vapour generator and provide improved heat contact of exhaust gases with the working fluid to reduce hydraulic resistance by 20-30%.

The vapour generator has a built-in exhaust manifold by tandem and its 10 connection is performed by quick-joint connectors, which enable it to be positioned to provide the required working fluid temperature and easy maintenance and replacement of the vapour generator.

The ejector comprises an inlet chamber with a removable ejecting nozzle and an ejected nozzle which is designed as an integral part of the inlet chamber, the is mixing chamber having a cylindrical or conical shape with an inlet to outlet diameter ratio equal to around 1.22:1 and the diffuser having an exit diameter equal to around 2.5 of the conical diameter and its length is equal to around 10-12 of the conical diameters and all these parts are connected in common assembly by mounting device.

The ejecting and ejected ejector nozzles have a conoid inlet which increases the ejector efficiency by 20-30%.

The end of the ejecting nozzle is located upstream of a mixing chamber at a distance approximately equal to 3.6 times the critical diameter of the ejecting nozzle.

The heat exchanger is formed from high conductivity materials, such as aluminium alloys, and has a case that is an integral unit and which has a central annular (inner) channel for heating or cooling media and it has also channels located concentrically and uniformly along perimeter and bottoms of these channels has free spaces for uniform liquid refrigerant distribution inside 30 channels and inside the central channel there is a flow rectifier formed by uniformly distributed fins along the channel perimeter and their length is equal to the heat exchanger length and the fins provide reliable heat contact with the heat exchanger case, improve heat transfer and reduce hydraulic resistance of the refrigerant vapour flow.

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The condenser and the vaporizer have air fins and are combined with a fan and drive means.

The condenser and the vaporiser have a triple-stopped drive and its switch over is matched with load by pressure relay or micro-processor, for example.

A connection with the condenser and the vaporiser is performed by dampers and pipe-lines and separate parts that have heat and sound insulation.

The working fluid is refrigerant R 134a (1,1,1,2- tetrafluoroethane).

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be better understood from the following non-limiting description of preferred embodiments, in which:

Fig. 1 shows a schematic of a vapour-jet ejector refrigerating machine (air conditioner) with pressure amplifier in accordance with an embodiment of the present invention;

is Fig. 2 shows a schematic of an alternative embodiment of a vapour-jet ejector refrigerating machine (air conditioner) of the present invention with two vapour generators and two ejectors;

Fig. 3 shows a cycle diagram of the vapour-jet ejector refrigerating machine (air conditioner) in accordance with an embodiment of the present invention;

Fig. 4 shows a schematic drawing of a vapour generator in accordance with an embodiment of the present invention;

Fig. 5 shows a schematic drawing of a pressure amplifier in accordance with an embodiment of the present invention;

Fig. 6 shows an ejector schematic drawing in accordance with an embodiment of 25 the present invention;

Fig. 7 shows a heat exchanger schematic drawing in accordance with an embodiment of the present invention;

Fig. 8 shows a time chart of the refrigerant delivery to the evaporator of the aircooler 6 by pulses;

Fig. 9 is a chart tracking the operation of pressure amplifier 2 of the vapour-jet

2019216253 12 Aug 2019 ejector refrigerating machine (air conditioner) of Fig. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

Preferred features of the present invention will now be described with particular reference to the accompanying drawings. However, it is to be understood that the 5 features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention.

It will be appreciated that the present invention will be described below in relation to a vapour-jet ejector refrigerating machine (air conditioner) using refrigerant R-134a, which is accepted as the most favourable refrigerant on the 10 market and recommended by the International Institute of Cold. However, it will be appreciated that the type of refrigerant used may vary as will be appreciated by those skilled in the art.

It will also be appreciated that the invention will be described below in relation to use with an internal combustion engine. However, it will be appreciated that the is invention could be equally applied for use with any heat source, and is not limited to merely internal combustion engines.

Referring to Fig. 1, a vapour-jet ejector refrigerating machine 100 in accordance with an embodiment of the present invention is depicted.

The machine 100 comprises a vapour generator system 1, which includes the 20 vapour generator where refrigerant is converted from liquid to a vapour. The vapour generator system 1 also includes a vapour superheater and a heat exchanger. A pressure amplifier 2 is provided in addition to the vapour generator

1. An ejector 3 is in communication with a condenser 4 with fins for heat transfer intensification and a triple-stepped fan. A receiver 5 is provided for 25 refrigerant accumulation during load variation.

An evaporator 6 with fins for heat transfer intensification and triple-stepped fan is provided in association with a device for pulse feed of the refrigerant which can be designed as an integrated unit or an assembly of separate parts. The device for pulse feed of the refrigerant can, for example, be a solenoid valve 7, in 30 association with a two-stepped pressure relay 8. Heat exchangers 9, 12 function to decrease the refrigerant temperature upstream of the condenser and to increase temperature downstream of the vapour generator 1, i.e. for liquid refrigerant supercooling before feeding it to the evaporator 6 and super-heating after the vapour generator 1 via non-retum valves 13. A solenoid valve 11 with its two6

2019216253 12 Aug 2019 stepped relay 10 which has a feedback in pressure and associated temperature are installed at the vapour generator 1 exit.

Fig. 2 depicts and alternative embodiment of a vapour-jet ejector refrigerating machine 110. This alternative embodiment comprises two vapour generators 1, 5 and two ejectors 3, with all the other parts of the system marked by the same reference numerals as the embodiment of Fig. 1.

Referring to Fig. 3 a schematic theoretical cycle in p-I” (pressure-enthalpy) diagram of the vapour-jet ejector refrigerating machine of the present invention is depicted. As previously discussed, this analysis of the present invention is io conducted with the refrigerant R-134a. The vapour-jet ejector refrigerating machine of the present invention uses a combined cycle. Here, the vapour cycle (Rankine cycle) 5-6-7-1'-10'-5 and the inverse cycle, cycle of the refrigerating machine 5-8-8-9-4-5 are combined.

In the present analysis, the pulse feed of the refrigerant to the evaporator 6 is instead of throttle feed is used. The Rankine cycle part includes the vapour generator 1, the ejector 3, and the condenser 4 and instead of accepted throttle device, pulse feed of the refrigerant to evaporator 6 is applied, and for this purpose solenoid valve 7 with a two-stage pressure relay 8 are used.

The developed and tested pulse system has the following benefits:

- In comparison with the existing throttle systems which all use expansion devices it decreases significantly hydraulic and heat losses.

- Evaporation temperature of the refrigerant is kept constant and does not depend on heat load. This means that pulse frequency increases with load rise and it reduces when heat load decreases.

- Work of cooling cycle decreases.

- Heat transfer process increases

- Refrigeration capacity increases.

It will be appreciated that these qualities are especially important for the low heat 30 loads.

According to the p-I” diagram of Fig. 3, the process in the vapour-jet ejector refrigerating machine has the following order:

1. Liquid refrigerant is heated by the heat of the exhaust gases until boiling

2019216253 12 Aug 2019 is achieved, thus generating a high pressure vapour. For example, for achieving a temperature equal to 80°C, vapour pressure is 2.6 Mpa. This process corresponds to the line 6-1 in Fig. 3.

2. The working vapour is then allowed to expand isentropically in the 5 ejecting nozzle from the vapour generator pressure P_w until the evaporator-air-cooler pressure P_o For example, for an evaporation temperature equal to 7°C, the pressure is equal to 0.375 Mpa. As can be seen from Fig. 3, this process line is parallel to constant entropy line - line l'-2S. In a real cycle the point 2S is lower due to losses. The cold vapour io is then mixed with the working vapour in the mixing chamber which is located after the ejected nozzle. The result of this process is marked by point 9. Upstream, the diffuser parameters of the refrigerant are defined by point 3.

3. The mixture of working and cold vapours is compressed until the 15 condensation pressure P_o is achieved, represented by line 3-4. Due to cooling by ambient air, the mixture converts to a liquid refrigerant in the condenser 4 (pressure and temperature of condensation depends on ambient air temperature), and this is represented by line 4-5 of Fig. 3. For example, if maximum ambient temperature is equal to 42°C, the expected 20 condensation temperature is 50°C and pressure P_o is equal approximately 1.32 Mpa. The major fraction of the refrigerant feeds the vapour generator, as depicted by line 5-6, and the minor one is directed by pulses to the evaporator 6 - as depicted by line 5-8'. Due to the pulse feed of the refrigerant, the refrigerating capacity q_o rises at the value Aq’ which is 25 represented by line 8-8'. This means q_o=q_o'+Aq_o. For the ejector parameters calculation it is convenient to use the gas dynamic functions, which connect adiabatic (isentropic) velocity with vapour thermodynamic parameters. For this purpose, dimensionless adiabatic velocity, λ is used:

³⁰ λ·=ω_αΙα„

2019216253 12 Aug 2019 (i) where ω_α -adiabatic velocity, m/s, a_cr - critical velocity, m/s.

Critical vapour velocity, a_cr, which is equal to local sound velocity, can be found from the equation:

^a A·⁵ cr= (^2fe/_fe+1P_fcF₆J where:

io k ^ration of specific heats, & ~ ^cp/^cv

P_b total pressure, P_a

V_b - specific volume calculated according to total vapour parameters

As the refrigerant is real gas, value is not constant. So the Laplace is equation should be applied.

a = (ΔΡ/Δρ)^ where:

a - average sound velocity for the range of pressure difference

ΔΡ small pressure difference of isentropic process

Δρ - density difference for corresponding pressure difference

Due to low air velocity before the ejector it can be neglected and air velocity in adiabatic process can be found as:

ω_α = 72(Δε)₃ where: (Ai)_s- enthalpy differences in isentropic process

From the condition ω_β = a. = a_cr ~ ίΔΡ\ ~ An ) 's and critical velocity is

O-cr V 2 (Δί^)^

Δϊςγ can be found as set out below.

2019216253 12 Aug 2019

In the “p-i” diagram of Fig. 3, an isentropic line is drawn from the point with initial total parameters Po, io. This line is parallel to the line S=_constant· Then several isobars P|, P₂, P3.. ..P_n in the range [P_w > P_o] are drawn and values

ΔΡ= (P_rP₂); (P₂ - P₃) etc are calculated. This enables the values J to be found. Such values are then compared with

Δί₅ = ίο — ς where . _ Oi + fy) _ O2 + ^3)

Go- 2 or^is0 “ 2 etc.

Then, from the equation — Ο.Β^ΔΡ^/Δρ^) p_ressure p_{cr can} b_e found and it is the isobar which together with i_cr defines the critical parameters.

With regard to Fig. 4, a schematic drawing of a vapour generator system 1 in accordance with an embodiment of the present invention is shown. The vapour generator system 1 includes a vapour super-heater and a heat exchanger. The vapour generator system comprises a case 15, which can be manufactured as a single-piece unit made from a high heat conductivity material, such as aluminium 15 alloy. Inside the case 15 there is a central channel 16 with a tube 17. The tube 17 and part 18 together form the free space 18' for the liquid refrigerant. Similarly, the tube 17 with part 19 forms free space 19' for the vapour super-heating. The Liquid to vapour volume ratio is equal to 1/3:2/3 respectively.

A flow rectifier 20 is located in the central channel and has a rod-fairing 21 with 20 uniformly located plates 22 which provide reliable contact with outer surface of an orifice. The plates 22 have a length not more than the length of the vapour generator system 1 and they function to improve heat contact of exhaust gases with the refrigerant and reduce hydraulic resistance of the exhaust manifold. The vapour generator system 1 is built inside the exhaust manifold and its connection 25 is performed by quick-joint connectors 28, which enable repair and replacement to be carried out on the system without system depressurisation occurring.

The central part 15 of the vapour generator system 1 is an integral unit located in two rows. The first or inner row has inserts 25 located where the film boiling takes place. The second or outer row 26 is provided for heat transfer 30 intensification and comprises channels 27 which are configured for connection with pressure amplifier and control instruments. Orifice 24 is used as the refrigerant outlet and orifice 23 for gas outlet.

2019216253 12 Aug 2019

Fig. 5 depicts a schematic drawing of the pressure amplifier 2 of a vapour jet ejector refrigerating machine according to the present invention. The pressure amplifier 2 functions to deliver refrigerant from the condenser 4 to the vapour generator system 1 described above. The pressure amplified 2 is configured to 5 replace a conventional hermetic pump.

In the condenser 4, the liquid refrigerant is at pressure which is lower than the pressure in the vapour generator. For example, for the considered system the liquid refrigerant pressure is equal to 1.32 MPa (for maximum condensation pressure 50° C for ambient temperature 42° C) whereas in the vapour generator, io pressure is equal to 2.6 MPa for accepted temperature of the refrigerant vapour equal to 80°.

In conventional systems, in order to raise the pressure of the liquid refrigerant, a hermetic pump has been employed. However, such a devicehas significant drawbacks as it is complex in design, requires an in-drive device for startup, slowdown and is protection control system, has short life expectancy due to rotating parts, and requires ongoing maintenance.

Thus, the design of the present device depicted in Fig. 5 overcomes mentioned above drawbacks. The device uses the pressure inside the vapour generator for pressure augmentation of liquid refrigerant from condensation pressure until the required value, 20 such that the liquid refrigerant can be delivered to the vapour generator (or heat absorber). As a result the need for such a complex and expensive device as the hermetic pump is avoided.

The pressure amplified of Fig. 5 consists of a case 2 having cylindrical spaces 50, 51, 54, 55, have two different diameters. Inside the spaces 50, 51, 54, 55 there 25 are cylinders 52, 53, 56 and 57 with two different diameters along their length.

The length and diameters of cylinders is calculated according to given operating conditions of the refrigeration system and refrigerant properties. Thus, free spaces 50, 51, 54, 55 have inlet and outlet orifices 58, 59, 61, 62, 63 with springand-ball stop valves 64, 65, 66, 67, 68, 69 with springs 70, 71, 72, 73, 74, 75.

The spaces of the case 2 are connected with the vapour generator 1 vapour space by holes 58, 6land accompanying pipe-lines, so as to deliver fluid refrigerant from the condenser to the vaporizer.

The pressure amplifier of Fig. 5, operates as following. Cylinders 50, 5land 54, 55 are configured to move in opposite direction. For this purpose holes in the 35 case 2 are located in such a way that during motion of the cylinder pairs 52, 53 and 56, 57 they are connected in turn with the vapour space of the vapour

2019216253 12 Aug 2019 generator. As a result high pressure is created in this space and the liquid refrigerant is delivered to the vapour generator uninterruptedly and at a constant pressure. The timing of the process is determined in such a way that total time, ^Tt, is the sum of the following times as show in Fig. 9, ^τί ⁼ A + ^τ'ΐ + A + where ^τ'ι = filling time of space for liquid, τ'₂ = time of pressure rise from condenser pressure, Pc, till pressure in vapour generator, Pw, τ'₃ io = release time of liquid portion, _τ' = time of pressure reduction in the vapour space from pressure in vapour generator, Pw, till condenser pressure, Pc·

The motion of the cylinders 52, 53, 56, 57 facilitates the suction and pumping processes of the system. This is achieved by the solid parts of the cylinders is functioning to open/close valves 58, 59, 60, 61, at regular intervals. When the cylinders 52, 53, 56, 57 are moved to the large cylinder diameter direction, the suction process takes place, and when the cylinders are moved in the opposite direction, the pumping process is achieved.

During the suction process, liquid refrigerant is drawn into the cylinder through 20 spaces 50, 51, whilst in the second cylinder with the spaces 54, 55, a pumping process is performed. These two processes go on concurrently and are organized in such a manner to ensure that liquid refrigerant is delivered into the vapour generator without intervals. This process is maintained due to the presence of hole 76. Hole 76 enables vapour residue confined between the large diameters of 25 the cylinder bodies to serve as damper as the other cylinder body is returned to its’ initial position. Such a design avoids pressure pulsation from occurring.

Figure 6 is a schematic drawing of the ejectors 3 of the vapour-jet ejector refrigerating machine 100. The ejector has two main parts: an inlet chamber 30 with removable ejecting nozzle 31 (critical diameter of the nozzle is calculated so by the procedure described above), and the ejected nozzle 32, which is designed as integral unit with the inlet chamber 30 and the mixing chamber 31. The mixing chamber 31 may have a cylindrical or conical shape with an inlet and outlet diameter ratio of 1.22:1. The diffuser 34 has a diameter equal to

2019216253 12 Aug 2019 approximately 2.5 diameters of the conical portion and its length is equal to approximately 10-12 diameters of the mixing chamber. All of these parts are connected in common assembly by mounting device 35. To reduce losses in the ejecting and ejected nozzle, either of these nozzles could include a conoid inlet.

The end of the ejecting nozzle 31 is upstream of the mixing chamber in a distance approximately equal to 3.6 of the ejecting nozzle critical diameters. The cross-section area of the mixing chamber is the sum of the exit cross-section areas of the ejecting nozzle 31 and the ejected nozzles 32.

Figure 7 is a schematic drawing of an embodiment of the heat exchanger 9 of the io vapour-jet ejector refrigerating machine of the present invention. The heat exchanger 9 can be formed from high heat conductivity materials, such as aluminium alloys or copper, and the main part of which, may be manufactured as an integral unit. In such an arrangement a central annular (inner) channel 41 is provided for cooling media and within the main part 40 there are channels 43 is located uniformly and concentrically along perimeter thereof. The main part 49 has a cover 44 and bottom 45 with holes formed therein forming the inlet and exit ports, which communicate with the free spaces 46, 47 of the the main part of the heat exchanger 40. Such an arrangement creates conditions for uniform distribution of the liquid refrigerant inside the channels 43. The central channel 20 41 has uniformly distributed fins provided therein and their length is equal to the overall length of the heat exchanger. The fins provide reliable heat contact with the main part 49 of the heat exchanger 40 and reduce hydraulic resistance of the refrigerant vapour.

Figure 8 is a chart of the refrigerant delivery to the evaporator of the air-cooler 6 25 by pulses. The refrigerant delivery is performed with a pressure difference

ΔΡ0 = 0.01-0.04 bars according to a given boiling temperature of 7° C, for example, i.e. Ρ₀₂' = P03 + ΔΡ₀.

When the load rises (lower part of the chart in Fig. 8) the refrigerant delivery frequency Ar_b Δτ₂... Δτ_η increases and when the load reduces (upper part of the 30 chart in Fig. 8) the refrigerant delivery frequency Δτι, Δτ₂. Δτ_η decreases.

It should be appreciated that response time is very short and this has an important benefit when comparing this system with expansion valves, where feedback is performed by a temperature boiling sensor which has large response time. In such situations, where low load fibrillation of the expansion valves is observed, 35 monitoring can be lost. The refrigerant delivery by pulses overcomes this problem; resulting in an operation that is stable for all loads.

2019216253 12 Aug 2019

Referring to Figure 9 an operation chart tracking the operation of the pressure amplifier 2 of the system 100 of Fig. 1, and of the two vapour generators system 110 of Fig.2, is depicted. The chart shows how the control system should be tuned for use with the system 110 of Fig. 2, or how the system operates when the 5 pressure amplifier 2 of the system 100 of Fig. 1, is used.

For the pressure amplifier 2 of system 100 of Fig. 1:

During opposing motion of the cylinders a lowered pressure is created in the one free space and the liquid refrigerant under condensation pressure, Pc, is sucked. At the second free space the pressure is increased until the vapour generator io pressure Pw is achieved, due to vapour delivery from the vapour space of the vapour generator.

For the system 110 of Fig. 2 having two vapour generators:

One of the solenoid valves 11 is closed and vapour is sucked off by two-staged pressure relay use to create the low pressure. After that, delivery line from the is condenser is switched on and the liquid refrigerant is fed under condensation pressure, Pc, and the vapour generator operator time τ/ + τ₂ί

The control system is tuned in such a way that covering time till constant pressure attainment is τ/ + τ/⁷ The tuning is performed by test.

With reference to Figs. 1 and 2, the proposed vapour-jet ejector refrigeration 20 machine air conditioner 100, 110 of the present invention operates as follows:

Heat generator (generators) 1, absorb heat from the combustion engine exhaust products or other similar heat source and transfers this heat to the refrigerant. As a result, the refrigerant boils and generates a high pressure vapour (for the present situation the boiling temperature is 80°C and the resultant vapour 25 pressure is 2.6 MPa).

The working vapour with pressure P_w flows to the ejector 3 (system 100) or ejectors 3 (system 110). The vapour leaves the ejector nozzle with high velocity, and functions to suck cold vapour from the evaporator (air cooler) 6 which is delivered at the beginning to the inlet chamber of the ejector. Then, with the 30 vapour pressure slightly below the evaporation pressure, there is a mixture of working and cold vapours being fed into the mixing chamber 32 of the ejector where they are then delivered to the diffuser 34 where the pressure raises till condensation pressure, Pc, is achieved. The condensation pressure will be dependent on the ambient temperature.

2019216253 12 Aug 2019

Liquid refrigerant is then delivered from the condenser to the receiver 5, which is a compensation volume for liquid refrigerant storage during load change. After the receiver 5, a minor fraction of liquid refrigerant, Go, which is required for car cooling is delivered to the pulse supply device of the refrigerant.

The major fraction of liquid refrigerant, G_w, arrives at the vapour generator 1. It will be appreciated that the pressure of the liquid refrigerant is significantly lower than the pressure in the vapour generator and it is the reason why a pressure amplifier (instead of a pump) is installed in the systems of the present invention.

io The above described pressure amplifier 2, employs vapour generators 1 as feedback elements, which increases the pressure from condensation pressure P_c to the pressure within the vapour generator. This replaces the hermetic pump of the prior art and provides constant pressure upstream of the ejector.

In the system 110 of Fig. 2, where two vapour generators and two ejectors is 15 applied, one of the vapour generators functions so that when the pressure of the liquid refrigerant decreases below condensation pressure Pc, the liquid refrigerant is delivered to the vapour generator until the pressure achieves the condensation pressure Pc. At this moment the liquid refrigerant supply is stopped and the source heat is heated. At the same time the boiling vapour from the 20 second vapour generator passes through the solenoid valve 11 to the ejector.

When the entirety of the liquid refrigerant converts to vapour inside the first generator, the control system switches off the second generator and switches on the first generator. This process is then repeated. As in the system 100 of Fig. 1, the operation of the system 110 is controlled so as to provide constant pressure 25 upstream of the ejector and excludes pressure pulsation. The required value of refrigerant which is delivered to the vapour generator 1 of Fig. 1, or vapour generators 1 of Fig. 2, is calculated according to refrigerating capacity.

For the refrigerant R-134a the following cycle parameters are accepted.

Heating of refrigerant in the vapour generator till 80°c ±1° corresponds to 30 operating pressure P_w = 2.36 MPa.

The maximum condensation temperature accepted in calculations and tested is 50°C which corresponds to ambient temperature 42°C and condensation pressure equal to Pc = 1.32MPa.

The evaporation temperature in the evaporator (air-cooler) is 7°c (+1) and the

2019216253 12 Aug 2019 desired air temperature at the air-cooler exit is t_e = 10-12°c.

It is known that heat coefficient^ i s equal ζ = Q_O/(Q_C- Q_o)' where Q_o -heat which was extracted from the evaporator, W [BTU],

Q_c - heat which was extracted from the condenser, W [BTU].

An experimental study which was performed with a model of the present invention in a car, enabled heat coefficient, ζ = 0.8-0.9 to be achieved. This was attained using the following system requirements:

- Application of vapour generators-superheaters-heat exchangers;

io - Application of pulse supply of refrigerant, which increases cooling capacity, decreases cycle work and decreases heat which is extracted from the refrigerant in the condenser;

- Application of pressure amplifier or scheme with 2 vapor generator and 2 ej ectors;

- Applying of triple heat regeneration.

These system requirements enabled the exclusion of a hermetic refrigerant pump, thereby reducing the specific quantity of metal present in the system and increasing the reliability and stability of the whole system, and reducing noise by 20 around 20-30 db.

It will be appreciated that the overall dimensions and weight of the device are not more than existing compressor air conditioners and it can be installed at the same place as it is for existing system.

Throughout the specification and claims the word “comprise” and its derivatives 25 are intended to have an inclusive rather than exclusive meaning unless the contrary is expressly stated or the context requires otherwise. That is, the word “comprise” and its derivatives will be taken to indicate the inclusion of not only the listed components, steps or features that it directly references, but also other components, steps or features not specifically listed, unless the contrary is 30 expressly stated or the context requires otherwise.

It will be appreciated by those skilled in the art that many modifications and

2019216253 12 Aug 2019 variations may be made to the methods of the invention described herein without departing from the spirit and scope of the invention.

The invention can be described in terms of provisional claims that can assist the skilled reader in understanding the various aspects and preferments of the 5 invention. However, these provisional claims are not to be construed as defining statements of the invention. It will be appreciated that other forms, aspects and preferred features of the invention and its embodiments described herein may ultimately be included in the claims defining the invention in the specifications of complete, international or national applications (or their subsequent io corresponding patent grants) that may claim priority from the provisional application accompanying this specification. In this context, the following nonlimiting claims assist to better describe the invention:

Claims (17)

1. An air conditioner for a system having at least one heat source comprising:

a working fluid for transferring energy about the system;

5 an ejector for receiving waste heat from exhaust gases of the at least one heat source to heat the working fluid;

a vapour generator for converting the working fluid from a liquid to a vapour;

a condenser for removing heat from the working fluid to convert 10 the working fluid from a vapour to a liquid; and a receiver for accumulating working fluid during load variation of the system;

wherein, the vapour generator comprises a pressure amplifier and the working fluid is delivered to the vapour generator from the ejector to 15 provide a prolonged supply of working fluid without pressure drop and the working fluid is delivered by pressure pulses which are correlated with a chosen boiling temperature of between 5-10°c and with a pressure difference of between 0.01-0.04 MPa, such that the heat transfer from the waste heat of the exhaust gases to the working fluid is performed in the 20 vapour generator by boiling the working fluid whereby phase conversion of the working fluid from liquid to gas causes the most effective heat absorption.

2. An air conditioner according to claim 1, wherein the pressure amplifier comprises a case having cylindrical spaces formed therein, the cylindrical

25 spaces have two different diameters extending along their length and in these spaces two cylinders with corresponding different diameters are located, inlet and outlet orifices are provided in walls of the spaces with each having a spring-and-ball stop valves controlling the opening and closing of the orifices, the stop valves being controllable such that during 30 motion of the cylinders the vapour spaces are in turn connected with to increase the pressure from condensation pressure of around 1.35 MPa for condensation pressure of the working fluid of around 50°C to a vapour generator pressure of around 2.6 MPa for a vapour temperature equal to around 80°C.

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3. An air conditioner according to claim 1, wherein the vapour generator is formed as an integral unit from materials of high heat conductivity, such as aluminium alloys.

4. An air conditioner according to claim 3, wherein the integral unit has a

2019216253 12 Aug 2019 solid case and is a heat accumulator having a channel formed in its centre for the exhaust products and a flow rectifier is located in the central channel and at a bottom of the case there is a receiver for receiving the liquid working fluid.

5 5. An air conditioner according to claim 4, wherein a cover is provided that also has free space that serves as a super-heater and a ratio of liquid and vapour volumes of the working fluid is equal to 1/3:2/3 and the case has two rows of channels formed along its perimeter to form an inner and outer channel, wherein the inner channel has inserts where film boiling 10 occurs and outer channel operates as a heat exchanger; in addition, in the case there are channels which connect the vapour space with the pressure amplifier and control instruments.

6. An air conditioner according to any one of the preceding claims, wherein the flow rectifier has rod fairing with uniformly located plates that provide

15 reliable contact with an outer surface of the orifice, the plates having a length not less than the length of the vapour generator and provide improved heat contact of exhaust gases with the working fluid to reduce hydraulic resistance by 20-30%.

7. An air conditioner according to any one of the preceding claims, wherein 20 the vapour generator has a built-in exhaust manifold by tandem and its connection is performed by quick-joint connectors, which enable it to be positioned to provide the required working fluid temperature and easy maintenance and replacement of the vapour generator.

8. An air conditioner according to any one of the preceding claims, wherein 25 the ejector comprises an inlet chamber with a removable ejecting nozzle and an ejected nozzle which is designed as an integral part of the inlet chamber, the mixing chamber having a cylindrical or conical shape with an inlet to outlet diameter ratio equal to around 1.22:1 and the diffuser having an exit diameter equal to around 2.5 of the conical diameter and its length is 30 equal to around 10-12 of the conical diameters and all these parts are connected in common assembly by mounting device.

9. An air conditioner according to claim 8, wherein the ejecting and ejected ejector nozzles have a conoid inlet which increases the ejector efficiency by 20-30%.

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10. An air conditioner according to claim 8, wherein the end of the ejecting nozzle is located upstream of a mixing chamber at a distance approximately equal to 3.6 of the critical diameter of the ejecting nozzle.

2019216253 12 Aug 2019

11. An air conditioner according to claim 1, wherein the heat exchanger is formed from high conductivity materials, such as aluminium alloys, and has a case that is an integral unit and which has a central annular (inner) channel for heating or cooling media and it has also channels located

5 concentrically and uniformly along perimeter and bottoms of these channels has free spaces for uniform liquid refrigerant distribution inside channels and inside the central channel there is a flow rectifier formed by uniformly distributed fms along the channel perimeter and their length is equal to the heat exchanger length and the fms provide reliable heat contact 10 with the heat exchanger case, improve heat transfer and reduce hydraulic resistance of the refrigerant vapour flow.

12. An air conditioner according to claim 1, wherein the condenser and the vaporizer have air fins and are combined with a fan and drive means.

13. An air conditioner according to claim 1, wherein the condenser and the 15 vaporiser have atriple-stopped drive and its switch over is matched with load by pressure relay or micro-processor, for example.

14. An air conditioner according to claim 1, wherein a connection with the condenser and the vaporiser is performed by dampers and pipe-lines and separate parts that have heat and sound insulation.

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15. An air conditioner according to claim 1, wherein the working fluid is refrigerant R 134a (1,1,1,2- tetrafluoroethane).

16. An air conditioner according to claim 1, wherein the atleast one heat source is an internal combustion engine.

17. An air conditioner according to claim 1, wherein the heat exchanger is 25 formed from high conductivity materials, such as aluminium alloys, and has a case that is an integral unit and which has a central annular (inner) channel for heating or cooling media and it has also channels located concentrically and uniformly along perimeter and bottoms of these channels has free spaces for uniform liquid refrigerant distribution inside 30 channels and inside the central channel there is a flow rectifier formed by uniformly distributed fms along the channel perimeter and their length is equal to the heat exchanger length and the fins provide reliable heat contact with the heat exchanger case, improve heat transfer and reduce hydraulic resistance of the refrigerant vapour flow.