A solar energy auxiliary combined heat and power system and operation method

Abstract

A solar energy auxiliary combined heat and power system and operation method, the system comprises a boiler, a high, medium and low pressure cylinder of a steam turbine, a condenser, a heat recovery system connected in sequence; further comprising a trough type solar heat collection system, a high and low temperature heat storage tank, an oil-water heat exchanger, a peak heater, a waste heat heater, an auxiliary heater, an absorption heat pump and various valves. During the daytime power peak and heat valley period, the solar energy drives the absorption heat pump and the peak heater, recovers the steam turbine exhaust and the waste heat of the heat network return water, under the premise of meeting the heat supply load, auxiliary improves the steam turbine power output; the excess solar heat is stored through the high temperature tank. During the night power valley and heat peak period, the high temperature tank releases heat to drive the absorption heat pump and the peak heater to recover the steam turbine exhaust and the waste heat of the heat network return water, which is used for heat supply of the heat network. The present application realizes the pure condensing condition operation of the combined heat and power unit in the heating season, and greatly improves the power output of the unit in the power peak period, and the peak regulation capacity is obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of combined heat and power, power station peak shaving and solar photothermal utilization, in particular to a solar auxiliary combined heat and power system and an operation method thereof. BACKGROUND

[0002] New energy power generation such as solar energy and wind energy has strong volatility and anti-peak shaving characteristics. The increase of new energy power generation in the grid brings great challenges to power grid peak shaving. With the rapid development of China's clean energy industry, the consumption of new energy power generation is still severe, and phenomena such as wind and light abandonment are widespread. At present, China's thermal power capacity is surplus, and the annual utilization hours of power generation equipment are low. In the future, the continuous low-load operation or deep peak shaving operation of thermal power units will become a normal state. The proportion of combined heat and power units in thermal power generation is large and wide, and improving the deep peak shaving capacity of combined heat and power units is a key technology for the consumption of renewable energy power generation. The current deep peak shaving technology of conventional combined heat and power units has the following problems:

[0003] (1) The peak shaving modes such as electric boiler, bypass main steam and cylinder cutting only reduce the power generation capacity of the unit during the power valley period. In order to improve the heating capacity, the unit extracts steam for heating during the power peak period, which affects the power generation capacity during the peak period.

[0004] (2) The existing combined heat and power peak shaving system has the problems of insufficient flexibility in parameter adjustment and insufficient flexibility in selection of heat source steam. The conventional unit peak shaving technology faces the actual problems of low energy utilization efficiency and small peak shaving depth. SUMMARY

[0005] In order to solve the problems existing in the prior art, the present application aims to provide a solar energy auxiliary combined heat and power system and operation method, in which, during the daytime power peak and low heat valley period, the solar energy is used to drive an absorption heat pump, to recover the exhaust steam waste heat and the heat network backwater waste heat of a steam turbine, and a sharp peak heater is used to heat the water at the outlet of the absorption heat pump evaporator to a specified temperature. Under the premise of meeting the heat supply load, the excess hot water is used to assist in heating the steam turbine regenerative system water, so as to improve the steam turbine power output; the excess solar energy in the daytime is stored through a high-temperature tank, and is used as a heat source at night. During the night power valley and high heat peak period, the high-temperature tank releases heat to drive the absorption heat pump, to recover the exhaust steam waste heat and the heat network backwater waste heat of the steam turbine, and the sharp peak heater is used to heat the water at the outlet of the absorption heat pump evaporator to a specified temperature, which is finally all used for heat network heating. The present application can operate in a pure condensing condition in the heating season, and the peak regulation flexibility is greatly improved, and the solar energy is used as an auxiliary heat source to further improve the power output of the unit during the power peak period, the solar energy driven absorption heat pump recovery system recovers waste heat, and the energy comprehensive utilization efficiency of the system is greatly improved. The present application realizes the flexible and rapid switching of the power station system peak-valley period working mode, and realizes the energy cascade and orderly utilization in the peak regulation process, and has high energy utilization efficiency, large peak regulation depth and flexible parameter regulation.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0007] The application relates to a solar energy auxiliary combined heat and power system, which comprises a boiler 201 main steam side, a turbine high-pressure cylinder 202, a boiler 201 reheat steam side, a turbine medium-pressure cylinder 203, a turbine low-pressure cylinder 204, a condenser 206, a seventh-stage regenerative heater 216 tube side, a sixth-stage regenerative heater 215 tube side, a fifth-stage regenerative heater 214 tube side, a fourth-stage regenerative heater 213 tube side, a deaerator 212, a second-stage regenerative heater 211 tube side, a first-stage regenerative heater 210 tube side and the boiler 201 main steam side which are sequentially connected in sequence; a groove type solar energy heat collecting system 101 heat conducting oil outlet pipeline is divided into two routes through a three-way switch valve A 105, one route sequentially passes through the oil side of an oil-water heat exchanger A 102, a three-way switch valve B 106 and is connected with the groove type solar energy heat collecting system 101 heat conducting oil inlet pipeline, and the other route sequentially passes through the oil side of an oil-water heat exchanger B 109, the three-way switch valve B 106 and is connected with the groove type solar energy heat collecting system 101 heat conducting oil inlet pipeline; a high-temperature heat storage tank 104 is connected with a regulating valve 107, the water side of the oil-water heat exchanger A 102, a water pump 108 and a low-temperature heat storage tank 103 in sequence through pipelines; the water side outlet of the oil-water heat exchanger B 109 is connected with a three-way control valve A 111, the generator of an absorption heat pump 118, a three-way control valve B 112 and the water side inlet of the oil-water heat exchanger B 109 in sequence through pipelines; the three-way control valve A 111 is connected with the three-way control valve B 112 through the shell side of a peak heater 110; the condenser outlet of the absorption heat pump 118 is connected with the tube side of the peak heater 110, a three-way switch valve C 113, the shell side of an auxiliary heater 116, a three-way switch valve D 114, the absorber of the absorption heat pump 118 and the condenser inlet of the absorption heat pump 118 in sequence; the three-way switch valve C 113 is connected with a heat network 115, the shell side of a waste heat heater 117 and the three-way switch valve D 114 in sequence through pipelines; the seventh-stage regenerative heater 216 tube side inlet is connected with the fourth-stage regenerative heater 213 tube side inlet in sequence through a three-way control valve C 207, the tube side of the auxiliary heater 116, a three-way control valve D 208; the condenser 206 tube side outlet is connected with a three-way control valve E 121, a three-way control valve G 120, the evaporator of the absorption heat pump 118, a three-way control valve G 119, a three-way control valve H 122 and the condenser 206 tube side inlet in sequence through pipelines; the three-way control valve G 120 is connected with the tube side of the waste heat heater 117 and the three-way control valve G 119 in sequence through pipelines; the three-way control valve E 121 is connected with a cooling tower 209 and the three-way control valve H 122 in sequence through pipelines; a generator 205 is connected with the turbine high-pressure cylinder 202, the turbine medium-pressure cylinder 203 and the turbine low-pressure cylinder 202 through a mechanical rotating shaft.The steam turbine 1# to 7# stage extraction pipeline from high to low is communicated with the first stage regenerative heater 210 shell side inlet, the second stage regenerative heater 211 shell side inlet, the deaerator 212 inlet, the fourth stage regenerative heater 213 shell side inlet, the fifth stage regenerative heater 214 shell side inlet, the sixth stage regenerative heater 215 shell side inlet, the seventh stage regenerative heater 216 shell side inlet respectively; the first stage regenerative heater 210 shell side is communicated with the second stage regenerative heater 211 shell side and the deaerator 212 in turn, the fourth stage regenerative heater 213 shell side is communicated with the fifth stage regenerative heater 214 shell side, the sixth stage regenerative heater 215 shell side, the seventh stage regenerative heater 216 shell side and the condenser 206 in turn.

[0008] The solar auxiliary combined heat and power system operation method, during the low heating valley period of the daytime power peak, operates in the following manner: the trough type solar heat collection system 101 is put into work, the three-way switching valve A 105 and the three-way switching valve B 106 are adjusted according to the electrical load and the heat load, so that the high-temperature heat conduction oil flow from the trough type solar heat collection system 101 is reasonably divided into two paths; the direction of the water pump 108 is adjusted and the opening degree of the valve 107 is adjusted, so that the low-temperature water in the low-temperature heat storage tank 103 is heated to become high-temperature water of a specified temperature by the oil-water heat exchanger A 102, and is stored into the high-temperature heat storage tank 104; the high-temperature hot water flowing out of the oil-water heat exchanger B 109 is divided into two paths, and is used as the heat source of the peak heater 110 and the generator of the absorption heat pump 118 respectively; the three-way control valve A 111 and the three-way control valve B 112 are adjusted, so that the outlet hot water of the peak heater 110 reaches the required temperature of the heat network 115; the three-way switching valve C 113 and the three-way switching valve D 114 are adjusted, under the premise of ensuring the water flow and the heat load of the heat network 115, the steam turbine regenerative system feedwater is heated by the auxiliary heater 116, and the three-way control valve C 207 and the three-way control valve D 208 are adjusted, so that the outlet water temperature of the auxiliary heater 116 pipe side is consistent with the outlet water temperature of the fifth stage regenerative heater 214 pipe side; the three-way control valve G 120 and the three-way control valve H 119 are adjusted, so that the temperature difference between the outlet heat network backwater temperature of the waste heat heater 117 shell side and the outlet water temperature of the auxiliary heater 116 shell side is kept within a preset temperature difference, and the temperature difference between the outlet water temperature of the waste heat heater 117 pipe side and the outlet water temperature of the absorption heat pump 118 evaporator is kept within a preset temperature difference; the three-way control valve E 121 and the three-way control valve I 122 are adjusted, so that the outlet warm water of the cooling tower 209 is consistent with the pipe water temperature between the three-way control valve H 119 and the three-way control valve I 122.

[0009] The operation method of the solar energy auxiliary combined heat and power system is as follows: during the power low valley and heat peak period at night, the trough type solar energy heat collection system 101 does not work, the pipe line where the trough type solar energy heat collection system 101 is located is closed by adjusting the three-way switching valve A 105 and the three-way switching valve B 106, the direction of the water pump 108 is adjusted, and the opening degree of the night heat load adjusting valve 107 is adjusted according to the night heat load, so that the high-temperature water in the high-temperature heat storage tank 104 becomes low-temperature water after releasing heat through the oil-water heat exchanger A 102, and is stored into the low-temperature heat storage tank 103; the three-way switching valve C 113, the three-way switching valve D 114, the three-way regulating valve C 207 and the three-way regulating valve D 208 are adjusted, so that the shell side and the tube side of the auxiliary heater 116 do not work; the three-way regulating valve A 111 and the three-way regulating valve B 112 are adjusted, so that the outlet water temperature of the peak heater 110 tube side is consistent with the required water temperature of the night heat network 115; the three-way regulating valve E 121, the three-way regulating valve G 120, the three-way regulating valve H 119 and the three-way regulating valve I 122 are adjusted, so that the temperature difference between the outlet water temperature of the evaporator of the absorption heat pump 118, the outlet water temperature of the tube side of the waste heat heater 117 and the warm water at the tube side inlet of the condenser 206 is kept within a preset temperature difference.

[0010] Compared with the prior art, the present application has the following advantages:

[0011] (1) During the power peak period, the peak heater is heated in stages, and the absorption heat pump fully recovers the steam turbine exhaust waste heat, achieving orderly utilization of energy in stages.

[0012] (2) During the power peak period, the solar energy auxiliary unit generates power, improving the power output of the unit during the power peak period and expanding the power peak shaving interval.

[0013] (3) Solar energy is used as the driving heat source of the peak heater and the absorption heat pump, greatly improving the primary energy saving rate of the system.

[0014] (4) The present application realizes the operation of the combined heat and power unit in pure condensing conditions in the heating season, improves the flexible switching speed of the power station system during the peak-low period, and has large peak shaving depth and flexible parameter adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a schematic diagram of a solar energy auxiliary combined heat and power system and an operation method of the present application. DETAILED DESCRIPTION

[0016] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0017] In order to realize efficient and flexible coupling of solar energy and combined heat and power units, the present application provides a solar energy auxiliary combined heat and power system, as shown in Figure 1As shown, the system comprises, in sequence, the boiler 201 main steam side, the turbine high-pressure cylinder 202, the boiler 201 reheat steam side, the turbine intermediate-pressure cylinder 203, the turbine low-pressure cylinder 204, the condenser 206, the seventh-stage regenerative heater 216 tube side, the sixth-stage regenerative heater 215 tube side, the fifth-stage regenerative heater 214 tube side, the fourth-stage regenerative heater 213 tube side, the deaerator 212, the second-stage regenerative heater 211 tube side, the first-stage regenerative heater 210 tube side, and the boiler 201 main steam side; the heat transfer oil outlet pipeline of the trough-type solar thermal collector system 101 is divided into two routes by the three-way switching valve A 105, one route sequentially passes through the oil side of the oil-water heat exchanger A 102, the three-way switching valve B 106, and the trough-type solar thermal collector system 101 heat transfer oil inlet pipeline, and the other route sequentially passes through the oil side of the oil-water heat exchanger B 109, the three-way switching valve B 106, and the trough-type solar thermal collector system 101 heat transfer oil inlet pipeline; the high-temperature thermal storage tank 104 is connected in sequence with the regulating valve 107, the water side of the oil-water heat exchanger A 102, the water pump 108, and the low-temperature thermal storage tank 103 through pipelines; the water side outlet of the oil-water heat exchanger B 109 is connected in sequence with the three-way control valve A 111, the generator of the absorption heat pump 118, the three-way control valve B 112, and the water side inlet of the oil-water heat exchanger B 109 through pipelines; the three-way control valve A 111 is connected with the three-way control valve B 112 through the shell side of the peak heater 110; the condenser outlet of the absorption heat pump 118 is connected in sequence with the tube side of the peak heater 110, the three-way switching valve C 113, the shell side of the auxiliary heater 116, the three-way switching valve D 114, the absorber of the absorption heat pump 118, and the condenser inlet of the absorption heat pump 118; the three-way switching valve C 113 is connected in sequence with the heat network 115, the shell side of the waste heat heater 117, and the three-way switching valve D 114 through pipelines; the seventh-stage regenerative heater 216 tube side inlet is connected in sequence with the three-way control valve C 207, the tube side of the auxiliary heater 116, the three-way control valve D 208, and the fourth-stage regenerative heater 213 tube side inlet through pipelines; the condenser 206 tube side outlet is connected in sequence with the three-way control valve E 121, the three-way control valve G 120, the evaporator of the absorption heat pump 118, the three-way control valve H 119, the three-way control valve I 122, and the condenser 206 tube side inlet through pipelines; the three-way control valve G 120 is connected in sequence with the tube side of the waste heat heater 117 and the three-way control valve H 119 through pipelines; the three-way control valve E 121 is connected in sequence with the cooling tower 209 and the three-way control valve I 122 through pipelines; the generator 205 is connected with the turbine high-pressure cylinder 202, the turbine intermediate-pressure cylinder 203, and the turbine low-pressure cylinder 202 through a mechanical rotating shaft;The steam turbine 1# to 7# stage extraction pipe with high to low pressure is communicated with the first stage regenerative heater 210 shell side inlet, the second stage regenerative heater 211 shell side inlet, the deaerator 212 inlet, the fourth stage regenerative heater 213 shell side inlet, the fifth stage regenerative heater 214 shell side inlet, the sixth stage regenerative heater 215 shell side inlet, the seventh stage regenerative heater 216 shell side inlet respectively; the first stage regenerative heater 210 shell side is communicated with the second stage regenerative heater 211 shell side and the deaerator 212 in turn, the fourth stage regenerative heater 213 shell side is communicated with the fifth stage regenerative heater 214 shell side, the sixth stage regenerative heater 215 shell side, the seventh stage regenerative heater 216 shell side and the condenser 206 in turn.According to the above system configuration, solar energy can be used as a peak heater and an absorption heat pump driving heat source, which can greatly improve the primary energy saving rate of the system.

[0018] In order to develop the economic and flexible potential of the solar energy auxiliary combined heat and power system more scientifically and effectively, the system is operated in the following manner during the daytime power peak and heat valley period: the trough type solar heat collection system 101 is put into operation, the three-way switching valve A 105 and the three-way switching valve B 106 are adjusted according to the electrical load and the heat load, so that the high-temperature heat conduction oil flowing out of the trough type solar heat collection system 101 is reasonably divided into two paths, one of which is used to drive the absorption heat pump 118 and the peak heater 110 to work, and the other of which is used to heat the water in the low-temperature heat storage tank 103 to become high-temperature water of a specified temperature through the oil-water heat exchanger A 102, and then the high-temperature water is stored in the high-temperature heat storage tank 104 and used as a heat source during the power valley period at night; the high-temperature hot water flowing out of the oil-water heat exchanger B 109 is divided into two paths and used as a heat source for the peak heater 110 and the generator of the absorption heat pump 118 respectively; by adjusting the three-way control valve A 111 and the three-way control valve B 112, the working fluid flow in the outlet pipeline of the three-way valve is reasonably distributed, so that the hot water outlet of the peak heater 110 reaches the required temperature of the heat network 115 after sufficient heat exchange; by adjusting the three-way switching valve C 113 and the three-way switching valve D 114, the working fluid flow in the outlet pipeline of the three-way valve is reasonably distributed, and under the premise of ensuring the water flow and heat load of the heat network 115, the steam turbine backheat system feedwater is heated by the auxiliary heater 116, the working fluid heat exchange process adopts an interwall heat exchanger, and the three-way control valve C 207 and the three-way control valve D 208 are adjusted to control the flow of the steam turbine backheat system feedwater in the auxiliary heater 116, so that the outlet water temperature of the auxiliary heater 116 is consistent with the outlet water temperature of the fifth-stage backheat heater 214; the three-way control valve G 120 and the three-way control valve H 119 are adjusted to control the flow of the coolant water into the evaporator of the absorption heat pump 118, so that the temperature difference between the outlet water temperature of the waste heat heater 117 and the outlet water temperature of the auxiliary heater 116 is kept within 3°C, and the temperature difference between the outlet water temperature of the waste heat heater 117 and the outlet water temperature of the absorption heat pump 118 is kept within 3°C; the three-way control valve E 121 and the three-way control valve F 122 are adjusted to control the flow of the circulating water into the cooling tower 209, so that the outlet water temperature of the cooling tower 209 is consistent with the water temperature in the pipeline between the three-way control valve H 119 and the three-way control valve F 122; during the power peak period, the peak heater is step-heated, and the absorption heat pump fully recovers the waste heat of the steam turbine exhaust steam, so that the energy can be used in an orderly manner in stages; at the same time, the solar energy auxiliary unit generates power, which can improve the power output of the unit during the power peak period and expand the power peak shaving interval.

[0019] The operation method of the solar energy auxiliary combined heat and power system operates in the following manner during the power valley and heat peak period at night: the trough type solar heat collection system 101 does not work, the three-way switching valve A 105 and the three-way switching valve B 106 are adjusted, so that the pipe line heat conducting oil working substance of the trough type solar heat collection system 101 does not flow, thereby closing the pipe line of the trough type solar heat collection system 101, the direction of the water pump 108 is adjusted, and the opening of the night heat load adjusting valve 107 is adjusted according to the night heat load, so that the high-temperature water in the high-temperature heat storage tank 104 releases heat through the oil-water heat exchanger A 102 and becomes low-temperature water, and is stored into the low-temperature heat storage tank 103, so that the energy storage device operates in the energy release condition; the three-way switching valve C 113, the three-way switching valve D 114, the three-way control valve C 207 and the three-way control valve D 208 are adjusted, so that the pipe line of the three-way valve is closed, and the high-temperature water working substance flows into the auxiliary heater 116, so that the shell side and the tube side of the auxiliary heater 116 do not work; the opening of each outlet of the three-way control valve A 111 and the three-way control valve B 112 is adjusted, so that the flow of the high-temperature working substance flowing into the absorption heat pump 118 and the peak heater 110 is controlled, and the water temperature at the outlet of the tube side of the peak heater 110 is consistent with the required water temperature of the night heat network 115 after the working substance is fully heat exchanged; the three-way control valve E 121, the three-way control valve G 120, the three-way control valve H 119 and the three-way control valve I 122 are adjusted, the working substance flow of the pipe line of the three-way valve is controlled, so that the temperature difference between the water temperature at the outlet of the evaporator of the absorption heat pump 118, the water temperature at the outlet of the tube side of the waste heat heater 117 and the water temperature at the inlet of the tube side of the condenser 206 is kept within 3 DEG C. Through the reasonable matching of the operation method and the system configuration, the present application can realize the operation of the heating season heat and power unit in the pure condensing condition, improve the flexible switching speed of the power station system in the peak-valley period, and has large peak regulation depth and flexible parameter adjustment.

Claims

1. A solar energy auxiliary combined heat and power system, comprising a boiler (201) main steam side, a steam turbine high pressure cylinder (202), a boiler (201) reheat steam side, a steam turbine intermediate pressure cylinder (203), a steam turbine low pressure cylinder (204), a condenser (206), a seventh stage regenerative heater (216) tube side, a sixth stage regenerative heater (215) tube side, a fifth stage regenerative heater (214) tube side, a fourth stage regenerative heater (213) tube side, a deaerator (212), a second stage regenerative heater (211) tube side, a first stage regenerative heater (210) tube side and a boiler (201) main steam side connected in sequence; a channel type solar energy heat collection system (101) heat conducting oil outlet pipeline is divided into two routes through a three-way switch valve A (105), one route is connected in sequence with the oil side of an oil-water heat exchanger A (102), a three-way switch valve B (106) and a channel type solar energy heat collection system (101) heat conducting oil inlet pipeline, the other route is connected in sequence with the oil side of an oil-water heat exchanger B (109), the three-way switch valve B (106) and the channel type solar energy heat collection system (101) heat conducting oil inlet pipeline; a high temperature heat storage tank (104) is connected in sequence with a regulating valve (107), the water side of the oil-water heat exchanger A (102), a water pump (108) and a low temperature heat storage tank (103) through pipelines; the water side outlet of the oil-water heat exchanger B (109) is connected in sequence with a three-way control valve A (111), an absorptive heat pump (118) generator, a three-way control valve B (112) and the water side inlet of the oil-water heat exchanger B (109) through pipelines; the three-way control valve A (111) is connected with the three-way control valve B (112) through the shell side of a peak heater (110); the condenser outlet of the absorptive heat pump (118) is connected in sequence with the tube side of the peak heater (110), a three-way switch valve C (113), the shell side of an auxiliary heater (116), a three-way switch valve D (114), an absorber of the absorptive heat pump (118) and the condenser inlet of the absorptive heat pump (118); the three-way switch valve C (113) is connected in sequence with a heat network (115), the shell side of a waste heat heater (117) and the three-way switch valve D (114) through pipelines; the seventh stage regenerative heater (216) tube side inlet is connected in sequence with a three-way control valve C (207), the tube side of the auxiliary heater (116), a three-way control valve D (208) and the fourth stage regenerative heater (213) tube side inlet; the condenser (206) tube side outlet is connected in sequence with a three-way control valve E (121), a three-way control valve F (120), an absorptive heat pump (118) evaporator, a three-way control valve G (119), a three-way control valve H (122) and the condenser (206) tube side inlet through pipelines; the three-way control valve F (120) is connected in sequence with the tube side of the waste heat heater (117) and the three-way control valve G (119) through pipelines; the three-way control valve E (121) is connected in sequence with a cooling tower (209) and the three-way control valve H (122) through pipelines;The generator (205) is connected with the high pressure cylinder (202), the middle pressure cylinder (203) and the low pressure cylinder (204) of the steam turbine through a mechanical rotating shaft; the steam extraction pipelines of the steam turbine 1# to 7# stages from high to low are communicated with the shell side inlets of the first stage regenerative heater (210), the second stage regenerative heater (211), the deaerator (212), the fourth stage regenerative heater (213), the fifth stage regenerative heater (214), the sixth stage regenerative heater (215) and the seventh stage regenerative heater (216) respectively; the shell side of the first stage regenerative heater (210) is communicated with the shell side of the second stage regenerative heater (211) and the deaerator (212) in sequence, and the shell side of the fourth stage regenerative heater (213) is communicated with the shell side of the fifth stage regenerative heater (214), the shell side of the sixth stage regenerative heater (215), the shell side of the seventh stage regenerative heater (216) and the condenser (206) in sequence.

2. The method of operating a solar assisted combined heat and power system of claim 1, characterized in that: During the day, when the electricity demand is high and the heat demand is low, the trough solar collector (101) works, according to the electricity load and heat load, the three-way switch valve A (105) and the three-way switch valve B (106) are adjusted, so that the high-temperature heat conducting oil flowing out of the trough solar collector (101) is divided into two paths; the direction of the water pump (108) is adjusted and the opening of the valve (107) is adjusted, so that the low-temperature water in the low-temperature heat storage tank (103) absorbs the heat of the heat conducting oil through the oil-water heat exchanger A (102) to become high-temperature water of a specified temperature, and is stored into the high-temperature heat storage tank (104); the high-temperature hot water flowing out of the oil-water heat exchanger B (109) is divided into two paths, which are used as the heat source of the peak heater (110) and the generator of the absorption heat pump (118) respectively; by adjusting the three-way control valve A (111) and the three-way control valve B (112), the outlet hot water of the peak heater (110) reaches the required temperature of the heat network (115); by adjusting the three-way switch valve C (113) and the three-way switch valve D (114), under the premise of ensuring the flow and heat load of the heat network (115), the steam turbine regenerative system feedwater is heated by the auxiliary heater (116), and the three-way control valve C (207) and the three-way control valve D (208) are adjusted so that the outlet water temperature of the auxiliary heater (116) and the outlet water temperature of the fifth-stage regenerative heater (214) are consistent; by adjusting the three-way control valve F (120) and the three-way control valve G (119), the outlet water temperature of the waste heat heater (117) and the outlet water temperature of the auxiliary heater (116) are kept within a preset temperature difference, and the outlet water temperature of the waste heat heater (117) and the outlet water temperature of the absorption heat pump (118) are kept within a preset temperature difference; by adjusting the three-way control valve E (121) and the three-way control valve H (122), the outlet warm water of the cooling tower (209) is consistent with the water temperature between the three-way control valve G (119) and the three-way control valve H (122).

3. The method of operating a solar assisted combined heat and power system of claim 1, wherein: During the night, when the electricity is low and the heat demand is high, the trough solar collector (101) is not working, by adjusting the three-way switch valve A (105) and the three-way switch valve B (106), the pipeline of the trough solar collector (101) is closed, the direction of the water pump (108) is adjusted, and the opening of the night heat load regulating valve (107) is adjusted according to the heat load, so that the high-temperature water in the high-temperature heat storage tank (104) releases heat through the oil-water heat exchanger A (102) and becomes low-temperature water, and is stored in the low-temperature heat storage tank (103); by adjusting the three-way switch valve C (113), the three-way switch valve D (114), the three-way regulating valve C (207) and the three-way regulating valve D (208), the shell side and the tube side of the auxiliary heater (116) are not working; by adjusting the three-way regulating valve A (111) and the three-way regulating valve B (112), the outlet water temperature of the tube side of the peak heater (110) is consistent with the required water temperature of the night heat network (115); by adjusting the three-way regulating valve E (121), the three-way regulating valve F (120), the three-way regulating valve G (119) and the three-way regulating valve H (122), the temperature difference between the outlet water temperature of the evaporator of the absorption heat pump (118), the outlet water temperature of the tube side of the waste heat heater (117) and the inlet water temperature of the tube side of the condenser (206) is kept within a preset temperature difference.

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