The method of operation of the heat pump and the heat pump for its implementation

 

(57) Abstract:

The invention relates to a process of converting thermal energy and can be used in the design and manufacture of heat pumps, refrigeration machines and heat transformers. The method of operation of a heat pump includes heating the working substance by heat from the cooling medium, the subsequent compression with increasing temperature in the adjacent vessel, the heat and pushing the working substance of the adjacent vessel. The proposed method differs that define the range of temperatures of the cooling medium, as a working substance, use the substance, which has a critical temperature greater than the minimum temperature Tminbut less than a maximum temperature Tmaxtemperature range cooling medium, while non-adiabatic compression of the working substance is subjected to a condition corresponding to the time of disappearance of the phase boundary, to a density of not less than 2 times the critical density, while working substance before compression result in one of the States with parameters satisfying the following conditions: TminTTkrfor any Tthe OHL.cfpre opredelennongo substances, Tkr, RkrVkrtemperature, pressure and volume of the working substance at the critical point, Tthe OHL.cf- the temperature of the cooled medium, Rminthe pressure corresponding to the plot of constant pressure on the isotherm with temperature TminVmax- the maximum volume of the working substance in the process boundary, where R=const and T=const at the same time when R=Rminand T=Tminafter which before compression increase the volume of the working substance until the disappearance of the phase boundary at P=const and T=const, and before pushing the pressure in the pressure device equalize with the pressure in the rest of the heat pump and the pressure exercised by the promotion. The heat pump includes a gripping device with the piston and the cylinder, adjacent the vessel, heat exchangers and working substance. Different proposed heat pump is the fact that it also includes a circulation pump connected to the heat exchanger cooling medium adjacent the vessel and the cylinder gripping device in a closed circulation loop variable volume and a maximum volume flow circuit is equal to the volume, allowing the working substance at T= Tminto make the state consistent with the positive coefficient on the current temperature of the cooling medium in the case of heat sources with variable temperature in a wide temperature range. 2 S. p. f-crystals, 1 Il.

The invention relates to a process of converting thermal energy and can be used in the design and manufacture of heat pumps, refrigeration machines and heat transformers.

The known method of operation of a heat pump /1/, which includes heating of the working substance by heat from the environment, its absorption and subsequent compression in the compressor with increasing temperature, the heat in the heated room, expansion of the working substance with decreasing temperature, while the working substance is chosen from the critical temperature is close to or equal to the ambient temperature, and the absorption of the working substance in the compressor to be done in the settings of his critical condition and compression lead to parameters for which the compressibility factor equal to one.

The disadvantage of this method is that the maximum heating coefficient is achieved only if a cooled environment as a source of heat, has a constant temperature. If a cooled environment has a variable temperature, for maximum heating coefficient in this way requires a change of the working substance. However, the A.

A device of the heat pump /2/ close to the claimed containing the compressor performs the functions of the gripping device, the heat exchangers, the two are not related circulation circuit with liquid carriers, each of which consists of two heat exchangers and heat exchanger of the primary circuit is placed in a cooled environment, and one heat exchanger of the secondary circuit is placed in a heated environment, the second heat exchangers placed in a vessel with a working substance, and the compressor is made so that the working volume of the cylinder is equal to half the volume of the working substance in the adjacent vessel.

The disadvantages of the known device should include the fact that the increase in the power of the device leads to a rapid increase in the volume of the cylinder and the adjacent vessel. In addition, the working medium after compression is heated directly in the adjacent vessel, so in this period the installation pauses. This circumstance with increasing plant capacity makes it necessary to manufacture and connection of new facilities for parallel operation. These drawbacks reduce the efficiency of the installation.

Solved the technical problem consisted in the development of the method and the device for its realizacijata the temperature of the cooling medium in the case of heat sources with variable temperature in a wide temperature range.

The essence of the proposed method is that the operation of the heat pump, including the heating of the working substance by heat from the cooling medium, the subsequent compression with increasing temperature, the heat and pushing the working substance is performed with the use of the working substance, which has a critical temperature greater than the minimum temperature Tminbut less than a maximum temperature Tmaxa predetermined temperature range cooling medium, while non-adiabatic compression of the working substance is subjected to a condition corresponding to the time of disappearance of the phase boundary, to a density of not less than 2 times the critical density, while working substance before compression result in one of the States with parameters satisfying the following conditions

TminTTkrfor any Tthe OHL.cf< / BR>
a predetermined temperature range,

PminPPkr,

VkrVmax,

where T, P, V temperature, pressure and volume of the working substance,

Tkr, RkrVkrtemperature, pressure and volume of the working substance at the critical point,

Tthe OHL.cftemperature is a temperature Tmin,

Vmax- the maximum volume of the working substance at the boundary of the process in which T=const and P=const simultaneously when P=Pminand T=Tmin,

then before compression increase the volume of the working substance until the disappearance of the phase boundary at T=const and P=const, and before pushing the pressure in the pressure device equalize with the pressure in the rest of the heat pump and pushing carried out at this pressure.

The invention is related to a heat pump, carrying out the proposed method, is that a heat pump, comprising a gripping device with the piston and the cylinder, adjacent the vessel, heat exchangers and working substance, also includes a circulation pump connected to the heat exchanger cooling medium adjacent the vessel and the cylinder gripping device in a closed circulation loop variable volume and a maximum volume flow circuit is equal to the volume, allowing the working substance at T= Tminto assume the state corresponding to the disappearance of the phase boundary.

When the cylinder gripping device and the adjacent vessel heat exchanger are heated environment.

At the same time, siege substance to the required density at any initial density, but not less than 2 times the density of the working medium at the critical point.

The technical result is achieved due to the fact that the produce selection of the working substance having a critical temperature between Tminand Tmaxtemperature range cooling medium, bringing the working substance before compression in the state with the maximum total internal energy, the compression of the working substance to the density at which the potential energy is completely converted into heat, and by a process of pushing after equalization of the pressure in the adjacent vessel and the pressure in the rest of the circulation circuit of the heat pump.

Selection of the working substance allows a significant reduction of the heating coefficient to use the working substance at a variable temperature of the cooled environment without replacement.

Bringing the working substance before compression in a state of maximum potential energy allows you to turn this energy into heat with only a slight increase of the work of compression.

The process of integrating the working substance in the balanced pressure in the compressing device and the rest of cicirello to simplify the design of the heat pump.

The heat extraction from the environment outside the volume of the adjacent vessel allows to increase the capacity of the heat pump by increasing the cycle frequency.

Temperatures below the critical temperature of the working substance reaches the state with the maximum total internal energy at the boundary of the process in which both P= const and T=const. In this case, the total internal energy equal to the latent energy of vaporization and kinetic energy, which is determined by the temperature of the working substance.

In the process, when P=const and T=const at the same time, the increase in the internal energy is only possible by increasing volume. But since T=const, then the kinetic energy of the working substance does not change when increasing the volume, therefore, the increase in the internal energy can occur only due to the increase in potential energy.

It is known that the vanishing point of the phase boundary (meniscus) of the liquid is converted into gas. In this state, the potential energy reaches its maximum value, this energy is equal to the latent heat of vaporization. The energy of vaporization depends on the individual properties of the working substance. To determine the need rassm*Vkr/Tkr=1/3. This means that at the critical point one third of the total energy is kinetic energy, and two - thirds of potential. As the critical point is a condition in which the boundary between liquid and gas, it is possible to conclude that the boundary of any process in which T=const and P=const at the same time, the internal potential energy equal to the energy of vaporization and, therefore, this energy is equal to two thirds of the total energy of the critical state. If the working substance with maximum potential energy to compress to a state in which the compressibility factor equal to one, then the potential energy is completely converted into kinetic energy.

With that said, for a rough estimation of the maximum value of the heating factor of the heat pump we can use the equality

< / BR>
where Q is the heat transferred in a heated environment,

And - work nonadiabatic compression

Tnathe temperature of the working substance at the beginning of compression,

Tkr- the critical temperature of the working substance,

TCCthe temperature of the working substance at the end of compression (in the ideal case, the temperature nagra in the beginning of the compression,

Vmin- the volume of the working substance at the end of compression.

From (1) it follows that the heating factor has the maximum value, if the compression process occurs when P=const. If TCC=Tnathen the heating rate is equal to the ratio of the energy of vaporization to the work of compression. All quantities in equation (1) can be measured directly.

The design feature of the proposed heat pump is that its path has a variable volume, which allows for a certain position of the piston to ensure the equality of the volume of the circulation loop volume, which is the mass of the working substance in a critical state of the working substance, and has the ability to grow to such a size that the working substance is heated to a temperature of cooling medium Tthe OHL.cfat Tthe OHL.cf<T krit was possible to put in the condition with the maximum internal energy (translate in a state of disappearance of the meniscus).

When this compressive device and adjacent the vessel made so that they provide the necessary increase circulation circuit and simultaneously provide compression of the working substance to a predetermined density. In addition, the shift of the air traffic management working substance.

The drawing shows a diagram of a heat pump that implements the proposed method. The heat pump contains 1 - heat exchanger, 2, 3, respectively, the cylinder and the piston compressing device, 4 - adjacent receptacle, 5 - thermometer, 6 - gauge, 7 - valve, 8 - heat exchanger, 9 - circulating pump, 10 - valve, 11 - oil pump high pressure, 12 - valve, oil pump, 13 - oil tank, 14 - bravamar 15 - valve, 16 - gauge, 17 - thermometer, 18 - gauge.

The heat pump is closed recirculation circuit, which sequentially includes: a valve 7, the heat exchanger 8, the circulation pump 9, the valve 10 adjacent the vessel 4 is connected to the gripping device consisting of a cylinder 2 and piston 3. The piston 3, the cylinder 2 and the adjacent vessel is placed in the vessel 1, which is a heat exchanger heated environment. The compressive device is equipped with a hydraulic compression system consisting of valves 12 and 15 oil high-pressure pump 11, the oil tank 13 with uravneniya 14 and 16 gauge. The operation of the heat pump control pressure gauges 6, 16, 18 and thermometers 5 and 17.

The heat pump operates as follows.

In the initial state, the piston 3 is at the position at which the volume of the circus is the banks of the process, where P=const and T= const at the same time. The cylinder 2 and the adjacent vessel 4 filled with the working substance in a state with the maximum internal energy. Before compression, the valves 10 and 7 are closed. Then the hydraulic system is activated, providing the compression process. The amount of displacement of the piston is determined by considering the initial and final density of the working substance. The compression process is controlled by the magnitude of the pumped oil from the oil tank uravneniya 14, and pressure gauges 6 and 16. At the end of the compression process opens the valve 7, and then the valve 10, the circulation pump 9. Under the action of the circulation pump 9 is pushing pressed the working substance and replace it with a new portion of the working substance in a state with the maximum internal energy. The process of pushing ends when the following sequence of operations: opens the valve 15 to reset the oil in the tank, closes the valve 7, the circulation pump 9 and pumps the working substance in the cavity adjacent the vessel and the cylinder gripping device and moves the piston to its original state. When the piston reaches the initial state closes the valve 10, the hydraulic system is activated and the cycle would repeat the boron heat.

In the drawing adjacent the vessel 4 is made as a continuation of the cylinder 2. With this design is the process of loading can be accomplished by displacement of the piston. However, if an adjacent vessel to produce from a set of tubes to the surface of the heat exchanger, the process of loading can be carried out only by the circulation pump. Shown in the drawing, the construction of the heat pump provides thermodynamic cycle without circulation pump. In this mode, the pushing is done by the piston, and the filling of the working substance related vessel and cylinder occurs under the action of internal pressure in the circuit.

The operation of the heat pump provides automatic control system that tracks changes in the temperature of the cooled environment, taking into account thermodynamic properties of working substance used on the saturation line.

An example of the method.

First, define the boundaries of the temperature change of the cooling medium Tminand Tmax. Thus there are two options. One option when cooled environment has an almost constant temperature for a sufficiently long time interval (commensurate with glutelin is, the waste heat of nuclear and thermal power plants, heat compressor stations, and geothermal heat. .. The second option is when the temperature of the cooling medium is changed in a certain range. Such heat sources, for example, should include heat atmospheric air, warm water of different water bodies, the heat of solar radiation.

Then, for each heat source is selected working medium to the heat pump.

If a cooled environment has a constant temperature, as the working substance, use the substance, which has a critical temperature equal to the temperature of the cooling medium. In this case, the heating coefficient is maximum and constant.

If the temperature of the cooling medium is changed between the minimum and maximum values, for example, the air temperature during the heating season from October to April, as the working substance is advisable to use such a substance, the critical temperature is close to the average air temperature during the heating season. In this case, the maximum heating factor will be achieved only when the ambient temperature is equal to the critical temperature this working substance.

For example, for climate zone with changing air temperatures from 263 to 293 K, it is advisable to use as the working substance monatomic gas xenon.

To determine the mass of xenon for the specific design of the heat pump it is necessary to determine the amount of part of the circuit, which includes the volume of the connecting piping, valves 7, 10, heat exchanger 8 and the working volume of the circulating pump 9. If the volume of this part of the circuit VtoCHK=10 l, the plunger gripping device is set so that the volume under the piston VPP=5 l In volume under the piston VtoPPpart of the working volume of the cylinder and the volume of the adjacent vessel. Full volume loop in this case will be equal to VtoPC=VtoCHK+VtoPP=15 liters of the Obtained volume is the critical volume. The critical density of the xenon =1.1 kg/L. Therefore, the required mass of xenon for this heat pump is equal to m = VtoPC= 16,5 kg When the critical volume volume under the piston is equal to 1/3(VtoPC)=5 l

To compress the working medium in critical condition to a final density required volume VtoPPreduce by 1/3, i.e. for VtoPP/3=5B>)=2/9(VtoPC).

So, we have obtained values of the volume for a particular heat pump when the critical state of the working substance: VtoPC, VtoCHK, VtoPPand Vcc. Regardless of the volume VCHKany other heat pump is the ratio of the volumes VtoPC, VtoCHK, VtoPPand VSScan't be changed. This circumstance allows, without changing the design of the heat pump to use as the working fluid is any substance having a critical temperature TminTkrTmax. Observed features are due to the law of corresponding ratios /3, 4/.

The knowledge of these volumes and their relationship allow thermodynamic cycle of the heat pump when the volume is more critical. The sequence of the cycle is as follows: the piston is set so that the volume of the circuit is equal to VtoPCthen the working substance is heated to a temperature of cooling medium, with the set pressure P. Then, the displacement of the piston (or the increase in the circuit) until the pressure P will remain constant. The beginning of the pressure drop P oz is the real energy. If this amount is twice the critical, i.e., VPC= 2VtoPC=30 l, in this case, the volume under the piston without adjacent vessel is equal to VPP= 20 l

The density of the working medium in this state equals =16.5 kg/30 l= 0.55 kg/l

Using the obtained results, determine how much you need to reduce the volume under the piston to compress the working medium to a final density.

During compression of the working substance to the critical density, the volume under the piston must be reduced in two times or VPP=10 l, and then the remaining amount be reduced by another 1/3, which is 3.33 liters Final volume will be equal to Vco= 20-10-3.33=6,57 L. Hence we find that the initial volume under the piston VPP= 20 l must be reduced to 13.33 litres.

In the automatic control mode of operation of the heat pump, the volume of the circuit is determined by the temperature of the cooled environment, taking into account thermodynamic properties of the working substance at saturation line and the piston is set immediately to its original state. Compression from initial to final density in this case is performed in one stage. When this compression is carried out at the maximum intensity of the heat from the cylinder wall SG is the same that is pushing the plunger gripping device at one stage. If adjacent vessel performed with the developed heat exchange surface, pushing up the volume of the adjacent vessel is carried out by the piston compressing device, and pushing the working substance of the adjacent vessel by circulating pump. To ensure that the promotion was made only by the circulation pump, to the input end of the pipe gripping device to attach the fixed end of the telescopic tube, and a movable end with the outlet mounted on the piston (not shown).

Examples of selection of the working substance.

If the cooling medium uses atmospheric air with Tmin= 253 K and Tmax=313 K, as the working substance choose one of the following substances: CO2or He or CF3Cl.

If as a cooled environment using geothermal water in natural sources with Tmin=293 K and Tmax=393 K, as the working substance choose one of the following substances CO2or CHF2Cl.

If as a cooling medium water use of natural and artificial reservoirs with Tmin THE2H4.

If as a cooling medium use and waste water nuclear or thermal power plants, or other industrial thermal plants with Tmin= 293 K and Tmax=393 K, as the working substance choose one of the following substances:2H3F2CL or Fl3or CH3CL.

The basis of operation of the proposed heat pump lies maximum effect mutual transformations of two types of internal energy - kinetic and potential, which occurs during the compression and expansion of the working substance.

This effect can be used in the development of high-efficiency transformers, heat and refrigeration.

Sources of information

1. RF patent 2083932 on the Way to achieve maximum heating rate of the heat pumps and installation for its implementation".

2. RF patent 2153133 on the Way to achieve maximum heating rate of the heat pumps and installation for its implementation".

3. L. D. Landau, E. N. Lifshitz Statistical physics Part 1, Nauka, 1976, pp. 286-288.

4. I. I. Novikov, "Thermodynamics". Engineering, 1984, pp. 402-406.

environment, subsequent compression with increasing temperature in the adjacent vessel, the heat and pushing the working substance of the adjacent vessel, characterized in that the determined temperature range cooling medium, as a working substance, use the substance, which has a critical temperature greater than the minimum temperature Tminbut less than a maximum temperature Tmaxtemperature range cooling medium, while non-adiabatic compression of the working substance is subjected to a condition corresponding to the time of disappearance of the phase boundary, to a density of not less than 2 times the critical density, while working substance before compression result in one of the States with parameters satisfying the following conditions:

TminTTkr< / BR>
for any Tthe OHL.cfa predefined temperature range;

PminPPkr;

VkrVVmax,

where T, P, V temperature, pressure and volume of the working substance;

Tkr, RkrVkrtemperature, pressure and volume of the working substance at the critical point;

Tthe OHL.cf- the temperature of the cooled environment;

Pminthe pressure corresponding to the area patwa on the border of the process, where P=const and T=const at the same time when R=Rminand T=Tmin,

then before compression increase the volume of the working substance until the disappearance of the phase boundary at P=const and T=const, and before pushing the pressure in the pressure device equalize with the pressure in the rest of the heat pump and the pressure exercised by the push.

2. A heat pump including a compression device with the piston and the cylinder, adjacent the vessel, heat exchangers and working medium, characterized in that it also includes a circulation pump connected to the heat exchanger cooling medium adjacent the vessel and the cylinder gripping device in a closed circulation loop variable volume and a maximum volume flow circuit is equal to the volume, allowing the working substance at T= Tminto assume the state corresponding to the disappearance of the phase boundary.

 

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FIELD: combined cooling and refrigeration systems.

SUBSTANCE: method comprises expanding air in the turbine up to a low temperature, heating air in the first heat exchanger with utilized heat, compressing air to the initial pressure in the compressor, withdrawing heat in the second feeding heat exchanger, and supplying compressed dry air to the receiver where the air is heated.

EFFECT: enhanced efficiency.

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