JPS61110849A - Heat pump system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improving the performance of a heat pump system, and more specifically, the present invention relates to improving the performance of a heat pump system. By increasing the pressure of the fluid supplied to the positive displacement compressor and increasing the fluid density,
The present invention relates to a heat pump system that increases the capacity of a positive displacement compressor.

[Prior art]

A heat pump system is a system that transfers thermal energy from a low-temperature heat source to a high-temperature heat source, and is widely used in various fields as an air-conditioning device and also as a waste heat recovery device due to the demand for energy saving. A widely known type of heat pump system is a compression type heat pump system that has a compression process using a compressor.

This compression heat pump system consists of an evaporator that absorbs thermal energy from a low-temperature heat source, a compressor that adiabatically compresses the heat medium vapor from the evaporator, and a compressor that increases the temperature and
It consists of a condenser that provides thermal energy from a pressurized heat medium to a high-temperature heat source, and a throttle mechanism such as an expansion valve that adiabatically expands the liquefied heat medium in the condenser. It is returned to the evaporator and is supplied for circulation.

When the compressor has a relatively low output (approximately 500
Reciprocating displacement type, rotary displacement type (including screw set), etc. positive displacement compressors are used, and for relatively large output, velocity type (centrifugal type, axial flow type) compressors are used. has been done. This is because the speed expansion compressor has the characteristic of processing a large amount of steam. Although positive displacement compressors have advantages such as a simple structure and the ability to obtain high pressure, they have the disadvantage that the capacity of the fluid that can be processed is small, which is one of the bottlenecks in increasing the output of heat pump systems.

On the other hand, the steam generated from the expansion valve is directly introduced into the compressor, resulting in a decrease in heat pump performance.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and a part of the compression is performed by a velocity expansion compressor placed before a positive displacement compressor, and the pressure of the fluid supplied to the positive displacement compressor is increased to increase the fluid density. By increasing the capacity of the fluid that can be processed by the positive displacement compressor, and by using the recovered thermal energy from the condensate discharged from the condenser to drive the speed expansion compressor. The aim is to improve the performance of heat pump systems.

[Structure of the invention]

The heat pump system of the present invention that achieves the above object is as follows:
An evaporator that absorbs thermal energy from a low-temperature heat source, a positive displacement compressor that boosts the pressure of heat medium vapor from the evaporator, and condensation that provides thermal energy from the heat medium pressurized by the positive displacement compressor to a high-temperature heat source. In a heat pump system consisting of a heat transfer vessel and an expansion valve that expands the heat medium liquefied in the condenser, a velocity expansion compressor is installed upstream of the positive displacement compressor to increase the density of the heat medium vapor and then expand the heat medium vapor. It is characterized by being supplied to a positive displacement compressor. Further, in the heat pump system of the present invention, in the heat pump system described above, the gas-liquid mixed heat medium drawn out from the expansion valve is guided to a gas-liquid separator that separates the vapor and liquid, and the heat separated by the gas-liquid separator is The present invention is characterized in that the medium vapor is guided to a vapor expander, and the velocity expansion compressor is driven by the power generated in the vapor expander.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a system of a heat pump system according to a first embodiment of the present invention, in which a heat medium liquid is supplied from a pipe 2 to an evaporator 1 that absorbs thermal energy from a low-temperature heat source. It absorbs heat and evaporates from the heat exchanger 3 to become steam S,
The vapor S is supplied to the positive displacement compressor 5 via a pipe 4, and a turbo compressor 22, which is a speed expansion compressor, is disposed upstream of the positive displacement compressor 5 in the pipe 4. It is supplied to the positive displacement compressor 5 in a high state. In addition, since the flow of steam in a reciprocating compressor is intermittent, there are pressure accumulators 23 at the front and rear.
Install 24.

The steam sucked into the displacement compressor 5 is compressed into high-temperature, high-pressure steam S, which is supplied to the condenser 7 via a pipe 6. Then, high-temperature thermal energy is supplied to the high-temperature heat source via the heat exchanger 8 in the condenser 7, and the steam S is condensed.

The heat medium condensed in the condenser 7 is transferred to a pipe 10
The gas is expanded at the expansion valve 11, and returned to the evaporator 1 as a gas-liquid mixed heat medium, where it is circulated and supplied.

The present invention is particularly characterized in that the heat medium vapor S from the evaporator 1 is supplied to the positive displacement compressor 5 via the turbo compressor 22. That is, by using the turbo compressor 22, the heat medium vapor S can be supplied to the positive displacement compressor 5 in a high density state, so the capacity that can be processed by the positive displacement compressor 5 can be increased, and the volume can be increased accordingly. The compact compressor 5 can be made smaller, and costs can be reduced.

FIG. 2 is a system diagram of a heat pump system according to a second embodiment of the present invention, and the differences from the first embodiment are as follows.
The driving power of the speed expansion compressor 22 is replaced by an electric motor, and the recovered thermal energy from the condensed liquid discharged from the condenser 7 is used, that is, the expansion valve 11 in the first embodiment is used.
As shown in FIG. 2, the gas-liquid mixed heat medium derived from the above is led to a gas-liquid separator 12 that separates it into vapor and liquid, and the heat medium vapor separated by the gas-liquid separator 12 is subjected to vapor expansion. Machine 1
4, and the velocity expansion compressor 22 is driven by the power generated in the steam expander 14.

That is, in FIG. 2, the heat medium supplied from the evaporator 1 to the condenser 7 and condensed in the condenser 7 expands via the pipe 10. It expands at the valve 11 and becomes liquid at the gas-liquid separator 12! , and steam S1. The steam S1 separated by the gas-liquid separator 12 is supplied to the steam expansion 1414 via the pipe 13, where it is expanded to below the evaporation pressure in the evaporator 1, becomes low-pressure steam S2, and is sent via the pipe 17. , low pressure condenser 18
It condenses here to become a low-temperature liquid 12, and is sent to the pipe 1.
9, the pressure is increased by a pump 20, and the mixture is supplied to a mixer 21. On the other hand, the liquid 2 separated in the gas-liquid separator 12 is supplied to the mixer 21 via the pipe 15, and is mixed with the liquid 12 to become liquid 1 at a predetermined temperature, which causes the pressure reducing valve 16 and the pipe 2 to be It is circulated and supplied to the evaporator 1 via the evaporator 1.

As mentioned above, the output of the vapor expander 14 is transferred to the turbo compressor 2.
2 (velocity expansion compressor), and by supplying the heat medium vapor S from the evaporator 1 to the positive displacement compressor 5 via the turbo compressor 22, As in the case of the first embodiment, the turbo compressor 22
Since the heat medium vapor S can be supplied to the positive displacement compressor 5 in a high-density state by using , the capacity that can be processed by the positive displacement compressor 5 can be increased, and the positive displacement compressor 5 can be made smaller accordingly. Therefore, costs can be reduced, and since the turbo compressor 22 uses the output of the vapor expander 14 as the driving force, it can operate independently and only use part of the power for compressing the heat medium vapor. can cover parts.

Although not carried out in the above embodiment, intermediate cooling can also be carried out by spraying the condensate onto the steam discharged from the turbo compressor 22.

An example of the performance of the heat pump system according to the above embodiment is specifically shown below using numerical values. Note that in this specific example, water is used as the heat medium.

(1) Condition of liquid l supplied to evaporator 1: 157°C +1
5ata, (158,3Kcal/kg) (2) State of steam S at the outlet of evaporator 1; 150°C, 4.85
ata, 1kg/hr, (655Kcal/kg)
(3) The state of steam S at the outlet of the turbo compressor 22! Q
: 235'C, 10ata, (698Kcal/
kg) (4) Condition of high temperature/high pressure steam S supplied to WE compressor 7: 355°C + 90ata, (713Kca
l/kg) (5) Condition of liquid discharged from condenser 7 = 300°C, 90ata, (321Kcal/kg
) (6) Condition after expansion valve 11: 197℃+15a
ta (7) Condition of liquid 11 at the outlet of gas-liquid separator 12: 197°C, 15ata, 0.74 kg/hr,
(201Kcal/kg) (8) State of steam S1 supplied to steam expander 14: 1
97℃, 15ata, 0.26 kg/hr, (6
66Kcal/kg) (9) Condition of steam S2 discharged from steam expander 14! @
: 32℃, 0.05ata, 0.26kg/hr
, (501Kcal/kg) α0) State of liquid l pressurized by pump 20: 32
°C, 15ata, (32Kcal/kg) (11)
Amount of heat supplied to evaporator 1: 505 Kcal/hr
'(12) Amount of heat obtained by the turbo compressor 22: 43
Kcal/hr (13) Amount of heat obtained by positive displacement compressor 5: 160 K
cal/hr (14) Amount of heat obtained in condenser 7: 520 Kcal
/hr (15) Thermal efficiency of steam expander 14: 0.9 (16
) Thermal efficiency of the turbo compressor 22: 0.75 (17) Thermal efficiency of the displacement compressor 5 = 1.0 Note that the capacity of the reciprocating compressor (displacement compressor 5) in the above specific example is compared with the conventional technology (
The results of comparison with the speed expansion compressor 22 (without speed expansion compressor 22) are shown in the table below.

Capacity of reciprocating compressor (processing steam amount 1 kg/hr) Conventional technology Condition of the present invention suction steam 150°C/4, 85a ta
235℃/10ata Suction steam flow rate 0.392 n
r/hr O,23Onr/hr Driving power (160+43) -203160Kcal/
hrKcal/hr As shown in the table, the amount of air flow to be processed by the reciprocating compressor can be reduced by about 40%, and the driving power can be reduced by about 20%.

Although water was used as the heat medium in the above specific example, any heat medium may be used in accordance with the spirit of the present invention, such as fluorocarbon-based heat media, Florinol 85, etc., and hydrocarbon-based heat media. Further, it goes without saying that the temperature, pressure, amount of heat, etc. in the above specific examples can also be set according to conditions.

〔Effect of the invention〕

As described above, the heat pump system of the present invention includes an evaporator that absorbs thermal energy from a low-temperature heat source, a positive displacement compressor that increases the pressure of the heat medium vapor from the evaporator, and a positive displacement compressor that increases the pressure of the heat medium vapor from the evaporator. In a heat pump system comprising a condenser that supplies thermal energy from a heat medium to a high-temperature heat source, and an expansion valve that expands the heat medium liquefied in the condenser, a velocity type compressor is provided in the front stage of the positive displacement compressor. The velocity expansion compressor increases the density of the heat medium vapor before supplying it to the positive displacement compressor. The capacity that can be processed by the compressor can be increased, and the positive displacement compressor can be made smaller to that extent, thereby reducing costs. Further, in the present invention, the gas-liquid mixed heat medium drawn out from the expansion valve is guided to a gas-liquid separator that separates it into vapor and liquid, and the heat medium vapor separated by the gas-liquid separator is guided to the vapor expander. Since the velocity expansion compressor is driven by the power generated in the vapor expander, the velocity expansion compressor operates independently and can cover part of the power for compressing the heat medium vapor. As described above, according to the present invention, part of the compression is performed by the velocity expansion compressor disposed upstream of the positive displacement compressor, and the heat medium vapor to be supplied to the positive displacement compressor is supplied in a high-density state, The performance of the heat pump system can be further improved by increasing the capacity that can be processed by the positive displacement compressor, and by using the recovered thermal energy from the condensate discharged from the condenser as the driving force for the speed expansion compressor. The practical effects of the present invention are extremely significant.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are system diagrams showing an embodiment of a heat pump system according to the present invention. DESCRIPTION OF SYMBOLS 1... Evaporator, 5... Positive displacement compressor, 7... Condenser, 11... Expansion valve, 12... Gas-liquid separator, 14...
...Steam expander, 22...Turbo compressor.

Claims (1)

[Claims] 1. An evaporator that absorbs thermal energy from a low-temperature heat source, a positive displacement compressor that increases the pressure of heat medium vapor from the evaporator, and a high-temperature compressor that increases the pressure of the heat medium vapor from the positive displacement compressor. In a heat pump system consisting of a condenser that provides thermal energy to a heat source and an expansion valve that expands the heat medium liquefied in the condenser, a velocity compressor is installed upstream of the positive displacement compressor, and the heat medium is A heat pump system characterized in that vapor is supplied to the positive displacement compressor after increasing its density. 2. In the heat pump system according to claim 1, the gas-liquid mixed heat medium derived from the expansion valve is guided to a gas-liquid separator that separates vapor and liquid, and the gas-liquid separator separates the vapor and liquid. A heat pump system characterized in that heat medium vapor is guided to a steam expander, and the speed type compressor is driven by the power generated in the steam expander.