KR20180017752A - Combined heat and power system with multiple expanders - Google Patents

Abstract

The present invention relates to a cogeneration system, and more specifically, relates to a cogeneration system with a plurality of expanders, which is able to respond to changes in a load. According to the present invention, the cogeneration system with the plurality of expanders comprises: a circulation pipe; a circulation pump installed on the circulation pipe to circulate a working fluid; a heat source to heat the working fluid flowing in the circulation pipe to convert the working fluid into high-temperature, high-pressure gas; a plurality of expanders to convert an expansion force of the working fluid in the high-temperature, high-pressure gas status into a rotatory power, which are connected in parallel; a condenser to exchange heat with the working fluid in a low-temperature, low-pressure gas status discharged from the expanders and to convert the working fluid into a low-temperature, low-pressure liquid status; a blocking valve installed to block the working fluid introduced into one or more of the expanders; a bypass line to connect a circulation pipe on a lower stream of the heat source and a circulation pipe on an upper stream of the condenser to allow the working fluid in the high-temperature, high-pressure gas status to circumvent the expanders; a differential pressure valve installed on the bypass line; and a controller to control the blocking valve, differential pressure valve, and circulation pump in accordance with the heat quantity required by a hot water load connected to the condenser.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a cogeneration system having a plurality of inflators,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cogeneration system, and more particularly, to a cogeneration system having a plurality of inflators to cope with fluctuations in load.

The heating system of apartment complexes such as apartment complexes has central heating, district heating, and individual heating depending on the way of supplying calories to a heating place.

The central heating is a method of heating a boiler or other heat source in a basement or a separate place from which a heating medium such as steam, hot water or hot air is supplied to each home.

Local heating is a type of heating system that supplies hot water produced in a large scale heat production facility such as a cogeneration power plant and a garbage incinerator to an apartment complex in a certain area through pipelines buried underground, instead of having individual heat production facilities in apartment complexes .

Individual heating is a method in which individual heaters are used in each house to heat them individually. Individual heating can be adjusted to allow each family to heat at the desired time, and it has the advantage of paying only as much as it uses. However, since the individual heating uses a small boiler, it has a disadvantage that the heat efficiency is lowered and the fuel cost is higher than the district heating.

To solve these drawbacks, a combined heat and power system with high energy efficiency has been proposed. A cogeneration system is a total energy system that simultaneously generates power and heat from a single energy source. Generally, a high temperature unit is used as a power source for generating electric power and a low temperature unit is used as a heat source. The domestic micro-cogeneration system using LPG or city gas as a heat source generates electricity by heating the working fluid by using the heat energy obtained by burning the gas, and supplies the heating or hot water by the remaining heat.

1 is a conceptual diagram briefly showing a conventional cogeneration system. 1, after heating a working fluid in a boiler 1, an inflator 2 connected to an alternator 4 is operated using a working fluid in a gaseous state at a high temperature and a high pressure to produce electricity The hot water stored in the hot water tank 3 is heated by a heat exchange method using the low-temperature and low-pressure working fluid discharged from the expander 2. The alternator 4 is connected to the rectifier circuit 5 and the rectifier circuit 5 is connected to the inverter 6. Since the inverter 6 requires a direct current as an input, the electricity generated in the alternator 4 is first converted into DC through the rectifying circuit 5, and then converted into AC that can be used at home in the inverter 6 again.

Patent Registration No. 10-1596485 Patent Registration No. 10-1596486 Patent Registration No. 10-1587253 Patent Registration No. 10-1264249 Patent Registration No. 10-1249445 Patent Registration No. 10-1587256

In the cogeneration system, the size of the load is not constant, and there is a problem that it is difficult to operate the single power generation module with high efficiency. SUMMARY OF THE INVENTION It is an object of the present invention to provide a cogeneration system having a plurality of power generation modules and capable of controlling the number of power generation modules according to load variations.

In order to achieve the above-mentioned object, the present invention provides a circulation pump for circulating a working fluid, a circulation pump installed in the circulation pipe for circulating the working fluid, and a circulation pump for circulating the working fluid flowing in the circulation pipe, A plurality of expanders connected in parallel to convert the expansion force of the working fluid in a gaseous state at a high temperature and a high pressure into a rotational force; A shutoff valve installed to shut off a working fluid flowing into at least one of the inflators, and a control valve for controlling the operation of the high-temperature and high- A circulation pipe on the downstream side of the heat source and an circulation pipe on the upstream side of the condenser are arranged so as to bypass the inflator And a controller for controlling the shut-off valve, the differential pressure valve, and the circulation pump in accordance with the amount of heat required in the hot water load connected to the condenser, and a plurality of expanders A cogeneration system is provided.

The controller also includes a plurality of inflators for controlling the circulation pump so as to maintain the differential pressure between both ends of the inflator by regulating the discharge pressure and the discharge flow rate of the working fluid discharged from the circulation pump.

The controller is further configured to control the shut-off valve to reduce the number of inflator activated when the amount of heat required in the hot water load increases, and to control the shut-off valve to control the differential pressure valve to increase the flow rate of the working fluid flowing through the bypass line The present invention provides a cogeneration system having an inflator of the present invention.

A second temperature sensor for transmitting an electric signal according to the temperature of the hot water recovered from the hot water load; a second temperature sensor for transmitting an electric signal according to the temperature of the hot water supplied to the hot water load; And a flow rate sensor for transmitting an electric signal corresponding to the flow rate of the hot water flowing through the first temperature sensor, the second temperature sensor and the flow rate sensor, wherein the controller calculates the heat quantity required in the hot water load through the electric signal received from the first temperature sensor, And a plurality of inflator for supplying the heat to the cogeneration system.

In addition, the controller provides a cogeneration system having a plurality of inflators that regulate the differential pressure valve to maintain differential pressure across the inflator.

The circulation pipe is provided with a first pressure sensor for transmitting an electric signal according to the pressure of the working fluid in the front end of the inflator and a second pressure sensor for transmitting an electric signal according to the pressure of the working fluid at the rear end of the inflator, The controller provides a cogeneration system having a plurality of inflators for measuring differential pressure across the inflator through electrical signals received at the first pressure sensor and the second pressure sensor.

The cogeneration system having a plurality of inflators according to the present invention can control the number of inflator drives according to load variations. Therefore, even if the amount of heat required by the load is not constant, it can be operated with high efficiency.

Further, there is an advantage that, even in the event of failure of some inflators, only the failed inflator can be replaced or repaired without stopping the entire system.

Another advantage is that alternate operation is possible when a part of inflator is operated.

1 is a conceptual diagram briefly showing a conventional cogeneration system.
2 and 3 are conceptual diagrams schematically showing an embodiment of the cogeneration system according to the present invention.
4 is a conceptual view briefly showing the inflator shown in Fig.

Hereinafter, preferred embodiments of the cogeneration system according to the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

2 and 3 are conceptual diagrams schematically showing an embodiment of the cogeneration system according to the present invention. 2 and 3, an embodiment of the cogeneration system according to the present invention includes a circulation pipe 10 and a circulation pump 11 through which a working fluid flows, a heat source 20 for heating a working fluid, (30), a condenser (40), and a controller (50).

The working fluid is responsible for absorbing and releasing heat energy by temperature and phase change. The working fluid transfers heat energy while utilizing the circulation line 10 connecting the respective components of the cogeneration system to each other.

In the present invention, methanol, ethanol, HFC refrigerant or HCFC refrigerant is preferably used as the working fluid.

In the cogeneration system according to the present invention, since the hot water tank is mainly used as the condenser 40, the condensation temperature of the working fluid must be higher than the temperature of the hot water stored in the hot water tank, so that the working fluid condenses through heat exchange in the condenser 40 Because. Since the circulating pump 11 can only pump liquid, the working fluid must be condensed after expansion. If another working fluid with a low condensation temperature is used, a separate condenser may be required in addition to the hot water tank.

The circulation pipe (10) is provided with a circulation pump (11) for circulating the working fluid. The circulation pump 11 needs oil to lubricate the circulation pump 11. The circulation pump 11 may be an inverter pump which can electronically control the discharge pressure and the discharge flow rate of the working fluid.

The heat source 20 may be a boiler including a tank in which water or oil is stored and a heating device for heating the tank. The heating device is disposed under the tank and heats the tank by burning fuel such as oil or gas supplied to the heating device 22. [ The heat source 20 may be an engine exhaust heat, a combustion gas exhaust heat, a waste heat discarded in various processes, or the like.

The vaporizer 21 may be a heat exchanger in which heat exchange between the heated water supplied from the heat source 20, oil or the like, and the working fluid occurs. The working fluid that has passed through the vaporizer 21 absorbs heat from water or oil heated by the heat source 20 and is converted into a high-temperature and high-pressure gas. Further, the vaporizer 21 may be integrally formed with the heat source 20. For example, the vaporizer 21 may be installed as a coil type pipe for heat exchange inside the tank of the boiler.

The circulation piping 10 is separated into four parts on the downstream side of the vaporizer 21. The divided circulation pipes 10a to 10d are provided with inflators 30a to 30d, respectively. Rotating alternators (not shown) are connected to the inflators 30a to 30d, respectively, so as to convert rotational kinetic energy of the inflators 30a to 30d into electric energy. At the upstream side of each inflator 30a to 30d, one shutoff valve 15a to 15d is provided.

4 is a conceptual view briefly showing the inflator shown in Fig. Referring to Figure 4, the inflator 30 includes a housing 33 and a rotor 34.

The housing 33 forms an internal space 35 divided into a working fluid inflow region 351 and a working fluid outflow region 352. The housing 33 is connected to the circulation pipe 10 on the upstream side of the inflator 30 to form an inlet 36 for supplying a working fluid in a gaseous state at a high temperature and a high pressure to the working fluid inflow region 351. The outlet 37 is connected to the waste working fluid outlet region 352 to supply the working fluid changed to the low temperature and low pressure gas state to the circulation pipe 10 on the downstream side of the inflator 30.

The rotor 34 is installed in the inner space 35 of the housing 33 and consumes thermal energy of the working fluid while rotating by the thermal energy of the working fluid in the gaseous state of high temperature and high pressure, . The rotor 34 includes a rotor 341 and a blade 342 installed along the longitudinal direction of the rotor shaft 341. [

In order for the rotor 34 to smoothly rotate, oil that maintains viscosity even under high-temperature and high-pressure conditions must be supplied to the interior of the inflator 30 together with the working fluid. The oil is supplied to the interior of the inflator (30) together with the working fluid through the inlet (36). And is discharged together with the working fluid through the outlet (37).

Referring again to FIGS. 2 and 3, a bypass line 14 bypassing the inflator 30 is provided in the circulation pipe 10. One end of the bypass line 14 is connected to the circulation pipe 10 between the evaporator 21 and the inflator 30 and the other end is connected to the circulation pipe 10 between the inflator 30 and the condenser 40.

The bypass line (14) is provided with a differential pressure valve (19). The differential pressure valve 19 is opened and closed in accordance with the differential pressure between the first pressure sensor 12 provided at the front end of the inflator 30 and the second pressure sensor 13 provided at the rear end of the inflator 30.

The working fluid discharged from the expander 30 passes through the condenser 40 to transfer the heat energy to the hot water load 1 while causing a phase change to a low temperature and low pressure liquid state.

A first temperature sensor 16 is installed in the supply pipe 41 connecting the condenser 40 and the inlet of the hot water load 1 and a return pipe 42 for connecting the outlet of the hot water load 1 to the condenser 40 The second temperature sensor 17 is provided. A flow rate sensor 18 is also installed in the return pipe 42.

The controller 50 serves to control the shutoff valve 15 and the differential pressure valve 19 in accordance with the variation of the hot water load 1. The variation of the hot water load 1 is determined by the temperature of the hot water supplied to the hot water load 1 received from the first temperature sensor 16, the second temperature sensor 17 and the flow sensor 18, Flow rate can be confirmed. That is, the controller can calculate the amount of heat required in the hot water load 1 through the temperature difference and the flow rate.

When the amount of heat required in the hot water load 1 is not particularly large, all of the four inflators 30a to 30d are operated and the bypass line 19 is shut off as shown in Fig.

If it is determined that the temperature difference between the hot water supplied to the hot water load 1 and the hot water recovered is large and the flow rate is large and the expansion device 30 is running all the time, As shown in FIG. 3, a portion of the shutoff valve 15 is closed to reduce the number of expanders 30 that are activated. In Fig. 3, the upper two shut-off valves 15a and 15b are shown as being closed. The differential pressure valve 19 is opened so that a part of the high temperature and high pressure gaseous working fluid discharged from the vaporizer 21 is directly supplied to the condenser 40 instead of the inflator 30 through the bypass line 14 Thereby corresponding to the demand of the hot water load 1.

In addition, the controller 50 serves to finely control the differential pressure valve 19 in accordance with the differential pressure across the inflator 30. The controller 50 can primarily control the differential pressure by controlling the discharge pressure and the discharge flow rate of the circulation pump 11 to control the flow of the working fluid in the liquid state, Through a differential pressure valve (19) for controlling the flow rate. The controller 50 calculates the differential pressure across the inflator 30 through the electrical signal received at the first pressure sensor 12 and the second pressure sensor 13 and adjusts the differential pressure valve 19 therewith, 30) to maintain the differential pressure at both ends constant. When the differential pressure increases, the differential pressure can be reduced by partially opening the differential pressure valve 19 and allowing the working fluid to flow through the bypass line 14 by lowering the pressure at the front end of the expander 30. [ Maintaining a constant pressure differential has the advantage of producing substantially constant electricity in an alternator connected to the inflator 30. It is also possible to prevent damage to the rectifier circuit (not shown) and the inverter (not shown) connected to the alternator.

2, the differential pressure valve 19 is shown as completely closed, but a portion of the differential pressure valve 19 may be opened to maintain the differential pressure.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

For example, although it has been described that the boiler is used as the heat source 20, a heat source in which the circulation pipe 10 is directly heated can also be used. At this time, a pin may be installed in the circulation pipe 10 at a heated position to improve heat transfer efficiency.

10: Circulating piping 11: Pump
12: first pressure sensor 13: second pressure sensor
14: bypass line 15: shutoff valve
16: first temperature sensor 17: second temperature sensor
18: Flow sensor 19: Differential pressure valve
20: heat source 21: vaporizer
30: inflator 40: condenser
50:

Claims (6)

A circulation pump installed in the circulation pipe for circulating the working fluid,
A heat source for heating the working fluid flowing through the circulation pipe and converting the working fluid to a high-temperature and high-pressure gas state,
A plurality of expanders connected in parallel to convert the expansion force of the working fluid in a gaseous state at a high temperature and a high pressure into rotational force,
A condenser for performing heat exchange with the working fluid in a low-temperature and low-pressure gaseous state discharged from the inflator and converting the working fluid to a low-temperature and low-pressure liquid state;
A shutoff valve installed to shut off the working fluid flowing into at least one of the inflators,
A bypass line connecting the circulation pipe on the downstream side of the heat source and the circulation pipe on the upstream side of the condenser so that the working fluid in a gaseous state at a high temperature and a high pressure bypasses the inflator,
A differential pressure valve installed in the bypass line,
And a controller for controlling the shut-off valve, the differential pressure valve, and the circulation pump according to the amount of heat required in the hot water load connected to the condenser. The method according to claim 1,
Wherein the controller controls the circulation pump so as to maintain the differential pressure between both ends of the expansion device by regulating the discharge pressure and the discharge flow rate of the working fluid discharged from the circulation pump. The method according to claim 1,
Wherein the controller controls the shut-off valve to reduce the number of inflator actuations when the amount of heat required in the hot water load increases, and controls the plurality of inflator valves to adjust the differential pressure valve to increase the flow rate of the working fluid flowing through the bypass line And a cogeneration system. The method of claim 3,
A second temperature sensor for transmitting an electric signal according to the temperature of the hot water recovered from the hot water load; a second temperature sensor for transmitting an electric signal according to the temperature of the hot water supplied to the hot water load; Further comprising a flow sensor for transmitting an electrical signal according to the flow rate of the fluid,
Wherein the controller comprises a plurality of expanders for calculating the amount of heat required in the hot water load through the electrical signals received from the first temperature sensor, the second temperature sensor and the flow rate sensor. The method according to claim 1,
Wherein the controller comprises a plurality of inflators for adjusting the differential pressure valve to maintain a differential pressure across the inflator. 6. The method of claim 5,
Wherein the circulation pipe is provided with a first pressure sensor for transmitting an electric signal according to the pressure of the working fluid in the front end of the inflator and a second pressure sensor for transmitting an electric signal according to the pressure of the working fluid at the rear end of the inflator, And a plurality of inflators for measuring a pressure difference across the inflator through electrical signals received at the first pressure sensor and the second pressure sensor.

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