Electric power peak-shaving and combined heat and power waste heat recovery device and operation method thereof

An inner power plant portion and a heat exchange station portion. The inner power plant portion includes a heat exchanger, a waste heat recovery electric heat pump, an energy-storing electric heat pump, high/low temperature water storing tanks, a heating network heater, a valve and a circulating water pump; the heat exchange station portion includes high/low temperature water storing tanks, an electric heat pump, a heat exchanger, a valve and a circulating water pump; as for the operating method of the device, the device can operate in periods of an electrical load trough, an electrical load flat and an electrical load peak respectively through combination of different valve switches, the high temperature water storing tank is used for balancing the difference between system heat supply amount and heating load, the low temperature water storing tank is used for stabilizing steam exhaust waste heat recovery amount.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a Continuation of international patent application PCT/CN2014/000187 filed Aug. 28, 2014, the disclosures of which are incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a heat exchanging device and operating method thereof, and in particularly, to an electric peaking combined heat and power (CHP) waste heat recovery device and an operating method thereof by using heat storing technology in combination with combined heat and power (CHP) and waste heat recovery. The present invention belongs to the technical field of energy and power.

BACKGROUND

Northern China belongs to areas that are rich in wind energy, and the wind power generation is growing rapidly in these regions; in addition, the installed capacity of wind energy is increasing year by year, and the proportion of the installed capacity of wind energy in the total installed capacity is also increasing year by year. However, the wind power has an anti-load characteristic, i.e., during the electrical load trough in the power grid at night, the wind power output is large, and during the electrical load peak in the power grid at daytime, the wind power output is small. Meanwhile, the difference between electrical load peak and electrical load trough is also expanding year by year, thus it is difficult to regulate the peak load.

Currently, the cities and towns in Northern China are still dependent on coal-fired boiler technology, which supplies the heat with high energy consumption and high pollution. Combined heat and power (CHP) is an efficient heating supply mode. However, the heat power plants in China operate in the way of ‘heat determines electricity’. In order to ensure heat supply, regulation ranges of the power output for many heat power plants are greatly limited, and the energy production cannot be reduced during the electrical load trough, thereby occupying the room of the wind generated electricity in the electrical grid, thus the wind power station has to limit its power output, which leads to phenomena of “fan suspending” in the areas that are rich in wind energy in Northern China.

Applying heat pump technology to recover exhaust waste heat of the combined heat and power (CHP) unit may further improve the heat supply efficiency of the combined heat and power (CHP), but it still cannot change the operating mode of ‘heat determines electricity’. The combined heat and power (CHP) may operate in the mode of ‘electricity determines heat’ by combining heat storage and the combined heat and power (CHP) unit through the heat storage stabilizing fluctuation of heat output, however, when in combination with the exhaust waste heat recovery technology in power plants, it still cannot ensure the stable recovery for the exhaust waste heat of the power plant.

SUMMARY

To solve the above problems, an object of the invention is to provide an electric peaking combined heat and power (CHP) waste heat recovery device and an operating method thereof by using heat storing technology in combination with combined heat and power (CHP) and waste heat recovery, so as to realize electric peaking combined heat and power (CHP) unit on the basis of realization of waste heat recovery.

In order to realize the above object, the invention adopts the following technical solution: an electric peaking combined heat and power (CHP) waste heat recovery device, characterized in that, the device comprises an inner power plant portion and a heat exchange station portion,

wherein the inner power plant portion mainly comprises a heat exchanger (1), a waste heat recovery electric heat pump (2), an energy-storing electric heat pump (3), a high temperature water storing tank (4), a low temperature water storing tank (5), a heating network heater (6), valves (11-19) and circulating water pumps (20-23); wherein an inlet of the heat exchanger (1) is connected to a primary network backwater pipe (1-1), and an outlet of the heat exchanger (1) is connected to inlets of the valve (11), the valve (12) and the circulating water pump (20) in parallel, respectively; an inlet of the waste heat recovery electric heat pump (2) is connected to an outlet of the valve (12), and an outlet of the waste heat recovery electric heat pump (2) is connected to an inlet of the heating network heater (6); a top inlet/outlet of the high temperature water storing tank (4) is connected to an outlet of the valve (13) and an inlet of the valve (14) in parallel, respectively, an inlet of the valve (13) is connected to an outlet of a condenser of the energy-storing electric heat pump (3) and an outlet of the valve (14) is connected to the inlet of the heating network heater (6); a bottom inlet/outlet of the high temperature water storing tank is connected to an outlet of the valve (15) and an inlet of the circulating water pump (21) in parallel, respectively, an inlet of the valve (15) is connected to an outlet of the circulating water pump (20), and an outlet of the circulating water pump (21) is connected to an inlet of the condenser of the energy-storing electric heat pump (3) via the valve (16); a top inlet/outlet of the low temperature water storing tank (5) is connected to an outlet of the valve (11) and an inlet of the valve (17) in parallel, respectively, and an outlet of the valve (17) is connected to an inlet of an evaporator of the energy-storing electric heat pump (3); a bottom inlet/outlet of the low temperature water storing tank (5) is connected to an outlet of the valve (18) and an inlet of the circulating water pump (22) in parallel, respectively, an inlet of the valve (18) is connected to an outlet of the evaporator of the energy-storing electric heat pump (3) via the circulating water pump (23), and an outlet of the circulating water pump (22) is connected to the inlet of the heat exchanger (1) in parallel via the valve (19);

wherein the heat exchange station portion mainly comprises a high temperature water storing tank (7), a low temperature water storing tank (8), an electric heat pump (9), a heat exchanger (10), valves (24-35) and a circulating water pump (36-37); wherein a top inlet/outlet of the high temperature water storing tank (7) is connected to an outlet of a valve (24) and an inlet of the circulating water pump (36) in parallel, respectively, an inlet of the valve (24) is connected to an outlet of the heating network heater (6) via a primary network water supply pipe (1-2), an outlet of the circulating water pump (36) connected to the primary network water supply pipe (1-2) in parallel via the valve (25) is connected to an inlet of the valve (26), and an outlet of the valve (26) is connected to an inlet of a primary network of the heat exchanger (10); a bottom inlet/outlet of the high temperature water storing tank (7) is connected to an outlet of the valve (27) and an inlet of the valve (28) in parallel, respectively, an inlet of the valve (27) is connected to an outlet of the primary network of the heat exchanger (10), and an outlet of the valve (28) is connected to an inlet of an evaporator of the electric heat pump (9); a top inlet/outlet of the low temperature water storing tank (8) is also connected to the outlet of the valve (27) and the inlet of the valve (28) in parallel, respectively, a bottom inlet/outlet of the low temperature water storing tank (8) is connected to an outlet of the valve (29) and an inlet of the valve (30) in parallel, respectively, and an outlet of the valve (30) is connected to the primary network backwater pipe (1-1); an outlet of the evaporator of the electric heat pump (9) is connected to an inlet of the circulating water pump (37) and the primary network backwater pipe (1-1) in parallel via the valve (31), respectively, and an outlet of the circulating water pump (37) is connected to an inlet of the valve (29); a secondary network backwater pipe (1-3) is connected to inlets of the valve (32) and the valve (33) in parallel, respectively, an outlet of the valve (32) is connected to an inlet of the secondary network of the heat exchanger (10), both outlets of the valve (33) and the secondary network of the heat exchanger (10) are connected to inlets of the valve (34) and the valve (35) in parallel, respectively, an outlet of the valve (35) is connected to a secondary network water supply pipe (1-4), an outlet of the valve (34) is connected to an inlet of a condenser of the electric heat pump (9), and an outlet of the condenser of the electric heat pump (9) is connected to the secondary network water supply pipe (1-4).

In a preferred embodiment, the heat exchanger (1) adopts a condenser or a water-water heat exchanger.

In a preferred embodiment, the heat exchanger (10) adopts a plate-type heat exchanger or an absorption-type heat exchanger unit.

An operating method for the electric peaking combined heat and power (CHP) waste heat recovery device described above, characterized in that, the operating method adjusts operating modes of the device through combination of different valve switches such that the device can operate in periods of an electrical load trough, an electrical load flat and an electrical load peak respectively:

1) during electrical load trough period: in the inner power plant portion, the valve (11), the valve (14), the valve (15), the valve (19), the circulating water pump (20) and the circulating water pump (22) are closed; the valve (12), the valve (13), the valve (16), the valve (17), the valve (18), the circulating water pump (21) and the circulating water pump (23) are open; primary network low temperature backwater provided by the primary network backwater pipe (1-1) flows into the heat exchanger (1) and the waste heat recovery electric heat pump (2) successively; the heat exchanger (1) and the waste heat recovery electric heat pump (2) recover exhaust waste heat of the combined heat and power (CHP) unit to heat the primary network low temperature backwater; the heated heating network water from the waste heat recovery electric heat pump (4) flows into the heating network heater (6), wherein the heated heating network water is steam extracted and heated by the combined heat and power (CHP) unit to a heating network design temperature to obtain primary network high temperature supply water flowing into the primary network water supply pipe (1-2) which supplies the primary network high temperature supply water; meanwhile, water stored in the high temperature water storing tank (4) is drawn from the bottom outlet via the circulating water pump (21) and flows into the condenser of the energy-storing electric heat pump (3); and after heat exchanged and heated, the water flows back into the high temperature water storing tank (4) from the top inlet; water stored in the low temperature water storing tank (5) is pressed from the top outlet and flows into the evaporator of the energy-storing electric heat pump (3), and after heat exchanged and cooled, the water is directed into the low temperature water storing tank (5) from the bottom inlet via the circulating water pump (23);

In the heat exchange station portion, the valve (25), the valve (26), the valve (27), the valve (30), the valve (32), the valve (35) and the circulating water pump (36) are closed; the other valves and the circulating water pump (37) are open; primary network high temperature supply water provided by the primary network water supply pipe (1-2) flows into the high temperature water storing tank (7) from the top inlet; the high temperature supply water is stored in the high temperature water storing tank (7), thus pressing middle temperature water stored in the high temperature water storing tank (7) from the bottom outlet and is mixed with middle temperature stored water pressed from the top outlet of the low temperature water storing tank (8); then the mixed water flows into the evaporator of the electric heat pump (9); after heat exchanged and cooled, the mixed water is divided into two branches, one of which is directed into the low temperature water storing tank (8) from the bottom inlet via the circulating water pump (37), and the other of which flows into the primary network backwater pipe (1-1); meanwhile, secondary network low temperature backwater provided by the secondary network water supply pipe (1-3) flows through the condenser of the electric heat pump (9); and after heat exchanging and heating the secondary network low temperature backwater, secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe (1-4) for supplying to heat users;

2) during electrical load flat period: in the inner power plant portion, the valve (16), the valve (18), the circulating water pump (21) and the circulating water pump (23) are closed; the energy-storing electric heat pump (3) is shut down; and the other parts operates in the same way as that during the electrical load trough period;

In the heat exchange station portion, the valve (24), the valve (25), the valve (29), the valve (30), the valve (33), the valve (35) and the circulating water pump (37) are closed; the other valves and the circulating water pump (36) are open; primary network high temperature supply water provided by the primary network water supply pipe (1-2) flows through a primary network side of the heat exchanger (10) and the evaporator of the electric heat pump (9) successively; after heat exchanging and cooling the primary network high temperature supply water, primary network low temperature backwater is obtained, which flows into the primary network backwater pipe (1-1); meanwhile, secondary network low temperature backwater provided by the secondary network backwater pipe (1-3) flows through a secondary network side of the heat exchanger (10) and the condenser of the electric heat pump (9) successively; and after heat exchanging and heating the secondary network low temperature backwater, secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe (1-4) for supplying to the heat users;

3) during electrical load peak period: in the inner power plant portion, the valve (12), the valve (13), the valve (16), the valve (17), the valve (18), the circulating water pump (21) and the circulating water pump (23) are closed; the valve (11), the valve (14), the valve (15), the valve (19), the circulating water pump (20) and the circulating water pump (22) are open; low temperature water stored in the low temperature water storing tank (5) is drawn from the bottom outlet and is mixed with the primary network low temperature backwater, and then the low temperature mixed water is sent to heat exchanger (1); the heat exchanger (1) recovers the exhaust waste heat of the combined heat and power (CHP) unit to heat the low temperature mixed water; the heated heating network water by the heat exchanger (1) is divided into two branches, one of which returns back into the low temperature water storing tank (5) from the top inlet, the other of which is directed into the high temperature water storing tank (4) from the bottom inlet via the circulating water pump (20); and high temperature water stored in the high temperature water storing tank (4) is pressed from the top outlet and then is sent to the heating network heater (6); wherein the high temperature water is steam extracted and heated by the combined heat and power (CHP) unit to a heating network design temperature to obtain the primary network high temperature supply water flowing into the primary network water supply pipe (1-2) which supplies the primary network high temperature supply water;

In the heat exchange station portion, the valve (24), the valve (28), the valve (29), the valve (31), the valve (33), the valve (34) and the circulating water pump (37) are closed; the electric heat pump (9) is shut down; the other valves and the circulating water pump (36) are open; high temperature water stored in the high temperature water storing tank (7) is drawn from the top outlet by the circulating water pump (36) and is mixed with the primary network high temperature supply water provided by the primary network water supply pipe (1-2); and then the mixed water flows through the primary network side of the heat exchanger (10); after heat exchanging and cooling the mixed water, middle temperature water is obtained and divided into two branches, one of which flows into the high temperature water storing tank (7) from the bottom inlet, the other of which flows into the low temperature water storing tank (8) from the top inlet, thus pressing low temperature water stored in the low temperature water storing tank (8) from the bottom outlet; the pressed low temperature water flows into the primary network backwater pipe (1-1); meanwhile, the secondary low temperature backwater provided by the secondary network backwater pipe (1-3) flows through the secondary network side of the heat exchanger (10); and after heat exchanging and heating the secondary low temperature backwater, secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe (1-4) for supplying to the heat users.

An electric peaking combined heat and power (CHP) waste heat recovery device, characterized in that, the device comprises an inner power plant portion and a heat exchange station portion,

wherein the inner power plant portion mainly comprises a heat exchanger (1), a waste heat recovery electric heat pump (2), an energy-storing electric heat pump (3), a high temperature water storing tank (4), a low temperature water storing tank (5), a heating network heater (6), valves (11-19) and circulating water pumps (20-23); wherein an inlet of the heat exchanger (1) is connected to a primary network backwater pipe (1-1), and an outlet of the heat exchanger (1) is connected to inlets of the valve (11), the valve (12) and the circulating water pump (20) in parallel, respectively; an inlet of the waste heat recovery electric heat pump (2) is connected to an outlet of the valve (12), and an outlet of the waste heat recovery electric heat pump (2) is connected to an inlet of the heating network heater (6); a top inlet/outlet of the high temperature water storing tank (4) is connected to an outlet of the valve (13) and an inlet of the valve (14) in parallel, respectively, an inlet of the valve (13) is connected to an outlet of a condenser of the energy-storing electric heat pump (3) and an outlet of the valve (14) is connected to the inlet of the heating network heater (6); a bottom inlet/outlet of the high temperature water storing tank is connected to an outlet of the valve (15) and an inlet of the circulating water pump (21) in parallel, respectively, an inlet of the valve (15) is connected to an outlet of the circulating water pump (20), and an outlet of the circulating water pump (21) is connected to an inlet of the condenser of the energy-storing electric heat pump (3) via the valve (16); a top inlet/outlet of the low temperature water storing tank (5) is connected to an outlet of the valve (11) and an inlet of the valve (17) in parallel, respectively, and an outlet of the valve (17) is connected to an inlet of an evaporator of the energy-storing electric heat pump (3); a bottom inlet/outlet of the low temperature water storing tank (5) is connected to an outlet of the valve (18) and an inlet of the circulating water pump (22) in parallel, respectively, an inlet of the valve (18) is connected to an outlet of the evaporator of the energy-storing electric heat pump (3) via the circulating water pump (23), and an outlet of the circulating water pump (22) is connected to the inlet of the heat exchanger (1) in parallel via the valve (19);

wherein the heat exchange station portion mainly comprises a low temperature water storing tank (8), an electric heat pump (9), a heat exchanger (10), valves (26-35) and a circulating water pump (37); wherein an inlet of the valve (26) is connected to an outlet of the heating network heater (6) via a primary network water supply pipe (1-2); an outlet of the valve (26) is connected to an inlet of a primary network of the heat exchanger (10); a top inlet/outlet of the low temperature water storing tank (8) is connected to an outlet of the valve (27) and an inlet of the valve (28) in parallel, respectively; an inlet of the valve (27) is connected to an outlet of the primary network of the heat exchanger (10), and an outlet of the valve (28) is connected to an inlet of an evaporator of the electric heat pump (9); a bottom inlet/outlet of the low temperature water storing tank (8) is connected to an outlet of the valve (29) and an inlet of the valve (30) in parallel, respectively, and an outlet of the valve (30) is connected to the primary network backwater pipe (1-1); an outlet of the evaporator of the electric heat pump (9) is connected to an inlet of the circulating water pump (37) and the primary network backwater pipe (1-1) in parallel via the valve (31), respectively, and an outlet of the circulating water pump (37) is connected to an inlet of the valve (29); a secondary network backwater pipe (1-3) is connected to inlets of the valve (32) and the valve (33) in parallel, respectively, an outlet of the valve (32) is connected to an inlet of a secondary network of the heat exchanger (10), both outlets of the valve (33) and the secondary network of the heat exchanger (10) are connected to inlets of the valve (34) and the valve (35) in parallel, respectively, an outlet of the valve (35) is connected to a secondary network water supply pipe (1-4), an outlet of the valve (34) is connected to an inlet of a condenser of the electric heat pump (9), and an outlet of the condenser of the electric heat pump (9) is connected to the secondary network water supply pipe (1-4).

In a preferred embodiment, the heat exchanger (1) adopts a condenser or a water-water heat exchanger.

In a preferred embodiment, the heat exchanger (10) adopts a plate-type heat exchanger or an absorption-type heat exchanger unit.

An operating method for the electric peaking combined heat and power (CHP) waste heat recovery device described above, characterized in that, the operating method adjusts operating modes of the device through combination of different valve switches such that the device can operate in periods of an electrical load trough, an electrical load flat and an electrical load peak respectively:

1) during electrical load trough period: in the inner power plant portion, the valve (11), the valve (14), the valve (15), the valve (19), the circulating water pump (20) and the circulating water pump (22) are closed; the valve (12), the valve (13), the valve (16), the valve (17), the valve (18), the circulating water pump (21) and the circulating water pump (23) are open; primary network low temperature backwater provided by the primary network backwater pipe (1-1) flows into the heat exchanger (1) and the waste heat recovery electric heat pump (2) successively; the heat exchanger (1) and the waste heat recovery electric heat pump (2) recover exhaust waste heat of the combined heat and power (CHP) unit to heat the primary network low temperature backwater; the heated heating network water from the waste heat recovery electric heat pump (4) flows into the heating network heater (6), wherein the heated heating network water is steam extracted and heated by the combined heat and power (CHP) unit to a heating network design temperature to obtain primary network high temperature supply water flowing into the primary network water supply pipe (1-2) which supplies the primary network high temperature supply water; meanwhile, water stored in the high temperature water storing tank (4) is drawn from the bottom outlet via the circulating water pump (21) and flows into the condenser of the energy-storing electric heat pump (3); and after heat exchanged and heated, the water flows back into the high temperature water storing tank (4) from the top inlet; water stored in the low temperature water storing tank (5) is pressed from the top outlet and flows into the evaporator of the energy-storing electric heat pump (3), and after heat exchanged and cooled, the water is directed into the low temperature water storing tank (5) from the bottom inlet via the circulating water pump (23);

In the heat exchange station portion, the valve (30), the valve (33), the valve (35) are closed; the other valves and the circulating water pump (37) are open; primary network high temperature supply water provided by the primary network water supply pipe (1-2) first flows through a primary network side of the heat exchanger (10); and after heat exchanged and cooled, the primary network high temperature supply water is mixed with middle temperature stored water pressed from the top outlet of the low temperature water storing tank (8), then the mixed water flows through the evaporator of the electric heat pump (9); after further heat exchanged and cooled, the mixed water is divided into two branches, one of which is directed into the low temperature water storing tank (8) from the bottom inlet by the circulating water pump (37), the other of which flows into the primary network backwater pipe (1-1); meanwhile, secondary network low temperature backwater provided by the secondary network water supply pipe (1-3) first flows through a secondary network side of the heat exchanger (10); after heat exchanged and heated, the secondary network low temperature backwater flows into the condenser of the electric heat pump (9); after further heat exchanging and heating the secondary network low temperature backwater, secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe (1-4) for supplying to heat users;

2) during electrical load flat period: in the inner power plant portion, the valve (16), the valve (18), the circulating water pump (21) and the circulating water pump (23) are closed; the energy-storing electric heat pump (3) is shut down, and the other parts operate in the same way as that during the electrical load trough period;

In the heat exchange station portion, the valve (29), the valve (30), the valve (33), the valve (35) and the circulating water pump (37) are closed; the other valves are open; primary network high temperature supply water provided by the primary network water supply pipe (1-2) flows through the primary network side of the heat exchanger (10) and the evaporator of the electric heat pump (9) successively, after heat exchanging and cooling the primary network high temperature supply water, the primary network low temperature backwater is obtained, which flows into the primary network backwater pipe (1-1); meanwhile, secondary network low temperature backwater provided by the secondary network backwater pipe (1-3) flows through a secondary network side of the heat exchanger (10) and the condenser of the electric heat pump (9) successively; and after heat exchanging and heating the secondary network low temperature backwater, secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe (1-4) for supplying to the heat users;

3) during electrical load peak period: in the inner power plant portion, the valve (12), the valve (13), the valve (16), the valve (17), the valve (18), the circulating water pump (21) and the circulating water pump (23) are closed; the valve (11), the valve (14), the valve (15), the valve (19), the circulating water pump (20) and the circulating water pump (22) are open; low temperature water stored in the low temperature water storing tank (5) is drawn from the bottom outlet and is mixed with the primary network low temperature backwater, and then the low temperature mixed water is sent to heat exchanger (1); the heat exchanger (1) recovers the exhaust waste heat of the combined heat and power (CHP) unit to heat the low temperature mixed water; the heated heating network water by the heat exchanger (1) is divided into two branches, one of which returns back into the low temperature water storing tank (5) from the top inlet, the other of which is directed into the high temperature water storing tank (4) from the bottom inlet via the circulating water pump (20); and high temperature water stored in the high temperature water storing tank (4) is pressed from the top outlet and then is sent to the heating network heater (6); wherein the high temperature water is steam extracted and heated by the combined heat and power (CHP) unit to a heating network design temperature to obtain the primary network high temperature supply water flowing into the primary network water supply pipe (1-2) which supplies the primary network high temperature supply water;

In the heat exchange station portion, the valve (28), the valve (29), the valve (31), the valve (33), the valve (34) and the circulating water pump (37) are closed; the electric heat pump (9) is shut down; the other valves are open; the primary network high temperature supply water provided by the primary network water supply pipe (1-2) flows through the primary network side of the heat exchanger (10), and flows into the low temperature water storing tank (8) after heat exchanged and cooled; the low temperature water stored in the low temperature water storing tank (8) is pressed from the bottom outlet and is sent to the primary network backwater pipe (1-1); meanwhile, the secondary network low temperature backwater provided by the secondary network backwater pipe (1-3) flows through the secondary network side of the heat exchanger (10), and after heat exchanging and heating the secondary network low temperature backwater, the secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe (1-4) for supplying to the heat users.

By applying the above technical solutions, the invention has the following advantages: 1. the waste heat recovery device of the invention comprises an inner power plant portion and a heat exchange station portion, wherein the inner power plant portion comprises a energy-storing and releasing system including an energy-storing electric heat pump, a high temperature water storing tank, a low temperature water storing tank, valves and circulating water pumps. During periods of the electrical load trough, the electrical load flat and the electrical load peak, the device adjusts the power output of the inner power plant portion and the electrical load of the heat exchanger station portion by intermittently operating the electric heat pumps in the inner power plant portion and the heat exchange station portion. The high temperature water storing tank is used for balancing the difference between system heat supply amount and heating load, the low temperature water storing tank is used for stabilizing steam exhaust waste heat recovery amount, thereby, thereby significantly improving the electric peaking capacity, and the problem that the electricity generation peaking capacity is limited due to mutual coupling of electricity generation and heat supply in traditional operating modes of ‘heat determines electricity’ in the CHP is solved, a CHP unit can adjust the grid power generation thereof and participate in power grid load regulation, the power grid regulating capacity can be improved so as to deal with the condition of constantly increasing of electrical load trough-to-peak difference, and the absorptive capacity of a power grid for wind power generation can be improved so as to reduce phenomena of ‘fan suspending’. 2. The waste heat recovering device of the invention may partially or fully recover the exhaust waste heat of the combined heat and power (CHP) unit, significantly improving the heat supply capacity of heat and power plant and the energy utilization efficiency of the system. 3. The invention also realizes “large temperature difference” heat supply of a primary network, which significantly expands the temperature differences between the supply water and backwater, improves the heat supply capacity of the existing pipe network by 50% without changing the primary network traffic; meanwhile, the present invention also realizes long-distance transportation.

DETAILED DESCRIPTION

The invention will be described in the following in details with reference to drawings and embodiments.

As shown inFIG. 1, the device of the invention comprises an inner power plant portion and a heat exchange station portion.

The inner power plant portion mainly comprises a condenser/water-water heat exchanger1, a waste heat recovery electric heat pump2, an energy-storing electric heat pump3, a high temperature water storing tank4, a low temperature water storing tank5, a heating network heater6, valves11-19and circulating water pumps20-23; wherein the inlet of the condenser/water-water heat exchanger1is connected to the primary network backwater pipe1-1, and the outlet of the condenser/water-water heat exchanger1is connected to the inlets of the valve11, the valve12and the circulating water pump20in parallel, respectively. The inlet of the waste heat recovery electric heat pump2is connected to the outlet of the valve12, and the outlet of the waste heat recovery electric heat pump2is connected to the inlet of the heating network heater6. The top inlet/outlet of the high temperature water storing tank4is connected to the outlet of the valve13and the inlet of the valve14in parallel, respectively, the inlet of the valve13is connected to the outlet of a condenser of the energy-storing electric heat pump3and the outlet of the valve14is connected to the inlet of the heating network heater6. The bottom inlet/outlet of the high temperature water storing tank4is connected to the outlet of the valve15and the inlet of the circulating water pump21in parallel, respectively, the inlet of the valve15is connected to the outlet of the circulating water pump20, and the outlet of the circulating water pump21is connected to inlet of a condenser of the energy-storing electric heat pump3via the valve16. The top inlet/outlet of the low temperature water storing tank5is connected to the outlet of the valve11and the inlet of the valve17in parallel, respectively, and the outlet of the valve17is connected to the inlet of an evaporator of the energy-storing electric heat pump3. The bottom inlet/outlet of the low temperature water storing tank5is connected to the outlet of the valve18and the inlet of the circulating water pump22in parallel, respectively, the inlet of the valve18is connected to the outlet of the evaporator of the energy-storing electric heat pump3via the circulating water pump23, and the outlet of the circulating water pump22is connected to the inlet of the condenser/water-water heat exchanger1in parallel via the valve19.

The heat exchange station portion mainly comprises a high temperature water storing tank7, a low temperature water storing tank8, an electric heat pump9, a plate-type heat exchanger10, valves24-35and circulating water pumps36-37; wherein the top inlet/outlet of the high temperature water storing tank7is connected to the outlet of the valve24and the inlet of the circulating water pump36in parallel, respectively, the inlet of the valve24is connected to the outlet of the heating network heater6via a primary network water supply pipe1-2, the outlet of the circulating water pump36connected to the primary network water supply pipe1-2in parallel via the valve25is connected to the inlet of the valve26, the outlet of the valve26is connected to the inlet of a primary network of the plate-type heat exchanger10. The bottom inlet/outlet of the high temperature water storing tank7is connected to the outlet of the valve27and the inlet of the valve28in parallel, respectively, the inlet of the valve27is connected to the outlet of a primary network of the plate-type heat exchanger10, and the outlet of the valve28is connected to the inlet of the evaporator of the electric heat pump9. The top inlet/outlet of the low temperature water storing tank8is also connected to the outlet of the valve27and the inlet of the valve28in parallel, respectively, the bottom inlet/outlet of the low temperature water storing tank8is connected to the outlet of the valve29and the inlet of the valve30in parallel, respectively, the outlet of the valve30is connected to the primary network backwater pipe1-1. The outlet of the evaporator of the electric heat pump9is connected to the inlet of the circulating water pump37and the primary network backwater pipe1-1in parallel via the valve31, respectively, and the outlet of the circulating water pump37is connected to inlet of the valve29. The secondary network backwater pipe1-3is connected to the inlets of the valve32and the valve33, respectively, the outlet of the valve32is connected to the inlet of the secondary network of the plate-type heat exchanger10, both the outlet of the valve33and the outlet of the secondary network of the plate-type heat exchanger10are connected to the inlets of the valve34and the valve35in parallel, respectively, the outlet of the valve35is connected to the secondary network water supply pipe1-4, the outlet of the valve34is connected to the inlet of the condenser of the electric heat pump9, and the outlet of the condenser of the electric heat pump9is connected to the secondary network water supply pipe1-4.

In a preferred embodiment, in the heat exchange station portion, the plate-type heat exchanger10may be replaced by absorption-type heat exchanger unit to reduce the water inlet temperature for the evaporator of the electric heat pump9such that the power consumption of the electric heat pump9is reduced.

Based on the electric peaking combined heat and power (CHP) waste heat recovery device provided in the above embodiment, the invention also provides a method for electric peaking combined heat and power (CHP) waste heat recovery, the method adjusts operating modes of the device through combination of different valve switches such that the device can operate in periods of an electrical load trough, an electrical load flat and an electrical load peak respectively:

1. during electrical load trough period: in the inner power plant portion, the valve11, the valve14, the valve15, the valve19, the circulating water pump20and the circulating water pump22are closed; the valve12, the valve13, the valve16, the valve17, the valve18, the circulating water pump21and the circulating water pump23are open; primary network low temperature backwater provided by the primary network backwater pipe1-1flows into the condenser/water-water heat exchanger1and the waste heat recovery electric heat pump2successively; the condenser/water-water heat exchanger1and the waste heat recovery electric heat pump2recover exhaust waste heat of the combined heat and power unit to heat the primary network low temperature backwater; the heated heating network water from the waste heat recovery electric heat pump4flows into the heating network heater6, wherein the heated heating network water is steam extracted and heated by the combined heat and power unit to a heating network design temperature to obtain primary network high temperature supply water flowing into the primary network water supply pipe1-2which supplies the primary network high temperature supply water; meanwhile, water stored in the high temperature water storing tank4is drawn from the bottom outlet via the circulating water pump21and flows into the condenser of the energy-storing electric heat pump3; and after heat exchanged and heated, the water flows back into the high temperature water storing tank4from the top inlet; water stored in the low temperature water storing tank5is pressed from the top outlet and flows into the evaporator of the energy-storing electric heat pump3, and after heat exchanged and cooled, the water is directed into the low temperature water storing tank5from the bottom inlet via the circulating water pump23.

In the heat exchange station portion, the valve25, the valve26, the valve27, the valve30, the valve32, the valve35and the circulating water pump36are closed; the other valves and the circulating water pump37are open; primary network high temperature supply water provided by the primary network water supply pipe1-2flows into the high temperature water storing tank7from the top inlet; the high temperature supply water is stored in the high temperature water storing tank7, thus pressing middle temperature water stored in the high temperature water storing tank7from the bottom outlet and is mixed with middle temperature stored water pressed from the top outlet of the low temperature water storing tank8; then the mixed water flows into the evaporator of the electric heat pump9; after heat exchanged and cooled, the mixed water is divided into two branches, one of which is directed into the low temperature water storing tank8from the bottom inlet via the circulating water pump37, and the other of which flows into the primary network backwater pipe1-1; meanwhile, secondary network low temperature backwater provided by the secondary network water supply pipe1-3flows through the condenser of the electric heat pump9; and after heat exchanging and heating the secondary network low temperature backwater with middle temperature water stored from the high temperature water storing tank7and the low temperature water storing tank8, secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe1-4for supplying to heat users.

2 during electrical load flat period: in the inner power plant portion, the valve16, the valve18, the circulating water pump21and the circulating water pump23are closed; the energy-storing electric heat pump3is shut down; and the other parts operates in the same way as that during the electrical load trough period;

In the heat exchange station portion, the valve24, the valve25, the valve29, the valve30, the valve33, the valve35and the circulating water pump37are closed; the other valves and the circulating water pump36are open; primary network high temperature supply water provided by the primary network water supply pipe1-2flows through a primary network side of the heat exchanger10and the evaporator of the electric heat pump9successively; after heat exchanging and cooling the primary network high temperature supply water, primary network low temperature backwater is obtained, which flows into the primary network backwater pipe1-1; secondary network low temperature backwater provided by the secondary network backwater pipe1-3flows through a secondary network side of the heat exchanger10and the condenser of the electric heat pump9successively; and after heat exchanging and heating the secondary network low temperature backwater with the primary network high temperature supply water, secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe1-4for supplying to the heat users, wherein the boot capacity of the electric heat pump9is less than that of the electric heat pump9during the electrical load trough period.

3 during electrical load peak period: in the inner power plant portion, the valve12, the valve13, the valve16, the valve17, the valve18, the circulating water pump21and the circulating water pump23are closed; the valve11, the valve14, the valve15, the valve19, the circulating water pump20and the circulating water pump22are open; low temperature water stored in the low temperature water storing tank5is drawn from the bottom outlet and is mixed with the primary network low temperature backwater, and then the low temperature mixed water is sent to the condenser/water-water heat exchanger1; the condenser/water-water heat exchanger1recovers the exhaust waste heat of the combined heat and power unit to heat the low temperature mixed water, wherein the amount of exhaust waste heat recovered by the condenser/water-water heat exchanger1is larger than that of the exhaust waste heat recovered by the condenser/water-water heat exchanger1during the electrical load trough period; the heated heating network water by the condenser/water-water heat exchanger1is divided into two branches, one of which returns back into the low temperature water storing tank5from the top inlet, the other of which is directed into the high temperature water storing tank4from the bottom inlet via the circulating water pump20; and high temperature water stored in the high temperature water storing tank4is pressed from the top outlet and then is sent to the heating network heater6; wherein the high temperature water is steam extracted and heated by the combined heat and power unit to a heating network design temperature to obtain the primary network high temperature supply water flowing into the primary network water supply pipe1-2which supplies the primary network high temperature supply water;

In the heat exchange station portion, the valve24, the valve28, the valve29, the valve31, the valve33, the valve34and the circulating water pump37are closed; the electric heat pump9is shut down; the other valves and the circulating water pump36are open; high temperature water stored in the high temperature water storing tank7is drawn from the top outlet by the circulating water pump36and is mixed with the primary network high temperature supply water provided by the primary network water supply pipe1-2; and then the mixed water flows through the primary network side of the heat exchanger10; after heat exchanging and cooling the mixed water, middle temperature water is obtained and divided into two branches, one of which flows into the high temperature water storing tank7from the bottom inlet, the other of which flows into the low temperature water storing tank8from the top inlet, thus pressing low temperature water stored in the low temperature water storing tank8from the bottom outlet; the pressed low temperature water flows into the primary network backwater pipe1-1; the secondary low temperature backwater provided by the secondary network backwater pipe1-3flows through the secondary network side of the heat exchanger10; and after heat exchanging and heating the secondary low temperature backwater, secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe1-4for supplying to the heat users.

In a preferred embodiment, as shown inFIG. 2, the heat exchange station portion may not contain the high temperature water storing tank7, at this operating mode, although during the periods of the electrical load trough, electrical load peak and electrical load peak, the heat exchange station portion provides different amount of heat supply, the thermal inertia of buildings may be used to maintain indoor temperature for human body comfort:

During the electrical load trough period: in the heat exchange station portion, the valve30, the valve33, the valve35are closed; the other valves and the circulating water pump37are open; the heat exchange station portion no longer stores the primary network high temperature supply water; the primary network high temperature supply water directly flows through the plat-type heat exchanger10and is mixed with the middle temperature water stored in the low temperature water storing tank8that is pressed from the top outlet, and then the mixed water flows into the evaporator of the electric heat pump9; after heat exchanged and cooled, the mixed water is divided into two branches, one of which is directed into the low temperature water storing tank8from the bottom inlet by the circulating water pump37, the other of which flows into the primary network backwater pipe1-1. Meanwhile, the secondary network low temperature backwater provided by the secondary network water supply pipe1-3firstly flows through the secondary network side of the plat-type heat exchanger10; after heat exchanged and heated, the secondary network low temperature backwater flows into the condenser of the electric heat pump9; after further heat exchanging and heating the secondary network low temperature backwater, the secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe1-4for supplying to the heat users, wherein the electric heat pump9operates at full capacity.

During the electrical load flat period, in the heat exchange station portion, the valve29, the valve30, the valve33, the valve35and the circulating water pump37are closed and the other valves are open; the low temperature water storing tank8no longer participate in heat storing or exothermic process; the primary network high temperature supply water provided by the primary network water supply pipe1-2flows through the primary network side of the plate-type heat exchanger10and the evaporator of the electric heat pump9successively; after heat exchanging and cooling the primary network high temperature supply water, the primary network low temperature backwater is obtained, which flows into the primary network backwater pipe1-1. Meanwhile, the secondary network low temperature backwater provided by the secondary network backwater pipe1-3flows through the secondary network side of the plate-type heat exchanger10and the condenser of the electric heat pump9successively; after heat exchanging and heating the primary network high temperature supply water, the secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe1-4for supplying to the heat users, now the electric heat pump9operates at part of capacity.

During electrical load peak period, in the heat exchange station portion, the valve28, the valve29, the valve31, the valve33, the valve34and the circulating water pump37are closed; the electric heat pump9is shut down; and the other valves are open; the primary network high temperature supply water provided by the primary network water supply pipe1-2flows through the primary network side of the plate-type heat exchanger10, and after heat exchanged and cooled, all of which flows into the low temperature water storing tank8; in turn the low temperature water stored in the low temperature water storing tank8is pressed from the bottom outlet and is sent to the primary network backwater pipe1-1. Meanwhile, the secondary network low temperature backwater provided by the secondary network backwater pipe1-3flows through the secondary network side of the plate-type heat exchanger10; and after heat exchanging and heating the secondary network low temperature backwater, the secondary network high temperature supply water is obtained, which flows into the secondary network water supply pipe1-4for supplying to the heat users.

The embodiments described above are only intended to further illustrate the object, technical solution and benefits of the invention in details, not for limiting the invention. Any modification, equivalent replacement and improvement that are made within the spirit and principle of the invention should be included within the scope of the invention.