Low-vacuum heating system coupled with large-temperature-difference heat pump and operation method of heating system

Abstract

The invention relates to a low-vacuum heating system coupled with a large-temperature-difference heat pump and an operation method of the heating system, and belongs to the technical field of combinedheat and power generation and energy conservation. The system includes a steam turbine, a condenser, a cooling tower, a heat exchanger of district heat supply network, a hydrophobic heat exchanger and a secondary heat exchanger station. The secondary heat exchanger station comprises a large-temperature-difference heat pump and a water-water heat exchanger. The heat exchanger of district heat supply network, the large-temperature-difference heat pump, the water-water heat exchanger, the hydrophobic heat exchanger and the condenser are sequentially installed on the loop of a primary network water supply and return pipe, and valves and bypasses are arranged at inlets and outlets of different devices. On the primary network side, the hydrophobic heat exchanger and the condenser are connectedin series or in parallel through the on-off states of the valves. On the secondary network side in a secondary heat exchange station, the large-temperature-difference heat pump and the water-water heat exchanger are connected in series or in parallel through the on-off states of the valves. The system and the method are based on the principle of energy cascade utilization, a coupling system is reasonably designed to achieve cascade heating of water in the district heat supply network, irreversible loss of the heat transfer process is reduced, and the system and the method have high practical application value.

Description

technical field [0001] The invention relates to a low-vacuum heating system coupled with a heat pump with a large temperature difference and an operating method, belonging to the technical field of combined heat and power energy saving. Background technique [0002] With the deepening of smog control in China, the development of central heating and the shutdown of small heating boilers have increasingly become the consensus of the government and the people. The development of urban central heating requires a stable heat source. Therefore, it has become an effective method to transform the existing pure condensing unit or heating unit to improve the heating capacity or to tap and release the heating potential. After the steam discharged into the low-pressure cylinder by the steam turbine of the thermal power plant does work, it enters the condenser to form condensation heat. The condensation heat usually accounts for more than 30% of the total input heat of its primary energy...

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Problems solved by technology

The second is the patent "a central heating system with a large temperature difference" with the application number 200810101065.X. The main features of the system are (1) on the heat source side, the steam-type absorption heat pump is used to recover the waste heat of the low-temperature circulating water in the thermal power plant, reducing the waste heat of the thermal power plant. (2) On the secondary network side, the hot water absorption heat pump and the water-to-water heat exchanger are connected in series, and the water supply temperature of the secondary network cannot be changed into the hot water absorption heat pump or the water-to-water heat exchanger Adjust the water flow of the secondary network

[0004] The shortcomings of the above two technical measures are: (1) The absorption heat pump unit is installed close to the heat source to achieve large temperature difference heating, but in the heat exchange station far away from the heat source, it is impossible to effectively use the large temperature difference heat supply; ( 2) The method of using steam absorption heat pump to recover the waste heat of circulating water in thermal power plants requires a large investment, which is much higher than the direct low-vacuum heating method. (3) On the secondary network side, the hot water absorption heat pump and water-to-water heat exchanger For series connection, the water supply temperature of the secondary network cannot be adjusted by adjusting the flow rate

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